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  • Question 1 - What is a true statement about the prion protein (PrPc)? ...

    Incorrect

    • What is a true statement about the prion protein (PrPc)?

      Your Answer: It is predominantly a beta-sheet structure

      Correct Answer: It can be broken down by protease

      Explanation:

      The prion protein has two forms: the normal form (PrPc) and the infectious form (PrPSc). The normal form can be broken down by proteases, while the infectious form is resistant to proteases.

      Prion Protein and its Role in Disease

      Prion protein is a type of infective agent that is composed of protein. It is made up of proteins called PrP, which exist in two forms: a normal form (PrPC) and an abnormal form (PrPSc). The abnormal form is resistant to protease, which means it cannot be broken down in the body. This abnormal form can change adjacent normal PrPC into the abnormal form, which is how the infection spreads.

      PrPC is a normal component of cell membranes and has an alpha-helical structure. However, in PrPSc, much of the alpha-helical structure is replaced by a beta-sheet structure. This change in structure causes PrPSc to aggregate into plaques in the extracellular space of the central nervous system, disrupting normal tissue structure.

      Prions cause disease by this disruption of normal tissue structure, leading to neurological symptoms and ultimately death. Understanding the structure and behavior of prion proteins is crucial in developing treatments and preventative measures for prion diseases.

    • This question is part of the following fields:

      • Neurosciences
      24.7
      Seconds
  • Question 2 - What is a true statement about sigma waves in relation to EEG? ...

    Correct

    • What is a true statement about sigma waves in relation to EEG?

      Your Answer: They are absent in familial fatal insomnia

      Explanation:

      Sigma waves are typically observed during stage 2 sleep and are considered a normal occurrence during sleep. They usually follow muscle twitches and are believed to help maintain a peaceful state during sleep. These waves are produced in the reticular nucleus of the thalamus and arise from the interplay between the thalamus and the cortex. However, in familial fatal insomnia (a prion disease), the absence of sigma waves is a characteristic feature.

      Electroencephalography

      Electroencephalography (EEG) is a clinical test that records the brain’s spontaneous electrical activity over a short period of time using multiple electrodes placed on the scalp. It is mainly used to rule out organic conditions and can help differentiate dementia from other disorders such as metabolic encephalopathies, CJD, herpes encephalitis, and non-convulsive status epilepticus. EEG can also distinguish possible psychotic episodes and acute confusional states from non-convulsive status epilepticus.

      Not all abnormal EEGs represent an underlying condition, and psychotropic medications can affect EEG findings. EEG abnormalities can also be triggered purposely by activation procedures such as hyperventilation, photic stimulation, certain drugs, and sleep deprivation.

      Specific waveforms are seen in an EEG, including delta, theta, alpha, sigma, beta, and gamma waves. Delta waves are found frontally in adults and posteriorly in children during slow wave sleep, and excessive amounts when awake may indicate pathology. Theta waves are generally seen in young children, drowsy and sleeping adults, and during meditation. Alpha waves are seen posteriorly when relaxed and when the eyes are closed, and are also seen in meditation. Sigma waves are bursts of oscillatory activity that occur in stage 2 sleep. Beta waves are seen frontally when busy of concentrating, and gamma waves are seen in advanced/very experienced meditators.

      Certain conditions are associated with specific EEG changes, such as nonspecific slowing in early CJD, low voltage EEG in Huntington’s, diffuse slowing in encephalopathy, and reduced alpha and beta with increased delta and theta in Alzheimer’s.

      Common epileptiform patterns include spikes, spike/sharp waves, and spike-waves. Medications can have important effects on EEG findings, with clozapine decreasing alpha and increasing delta and theta, lithium increasing all waveforms, lamotrigine decreasing all waveforms, and valproate having inconclusive effects on delta and theta and increasing beta.

      Overall, EEG is a useful tool in clinical contexts for ruling out organic conditions and differentiating between various disorders.

    • This question is part of the following fields:

      • Neurosciences
      15.9
      Seconds
  • Question 3 - What is the most effective method for distinguishing between Alzheimer's disease and Lewy...

    Incorrect

    • What is the most effective method for distinguishing between Alzheimer's disease and Lewy body dementia?

      Your Answer: Functional MRI

      Correct Answer: Dat scan

      Explanation:

      It’s important to note that DaT-SCAN and SPECT are not the same thing. DaT-SCAN specifically refers to the radioactive isotope called Ioflupane, which is utilized in the creation of a SPECT image.

      Alzheimer’s disease can be differentiated from healthy older individuals by using SPECT imaging to detect temporal and parietal hypoperfusion, according to studies such as one conducted by W. Jagust in 2001. Additionally, SPECT imaging has proven to be a useful tool in distinguishing between Alzheimer’s disease and Lewy body dementia, as demonstrated in a study by Vaamonde-Gamo in 2005. The image provided shows a SPECT scan of a patient with Alzheimer’s disease compared to one with Lewy body dementia, with the latter showing lower perfusion in the occipital cortex and the former showing lower perfusion in medial temporal areas.

    • This question is part of the following fields:

      • Neurosciences
      14.3
      Seconds
  • Question 4 - What stage of sleep do most adults spend the majority of their time...

    Incorrect

    • What stage of sleep do most adults spend the majority of their time in during the night?

      Your Answer: Stage 5/REM sleep

      Correct Answer: Stage 2

      Explanation:

      – Dement and Kleitman (1957) classified sleep into five stages.
      – Normal adults spend the majority of their sleep in Stage 2 (55%).
      – Non-REM sleep is divided into four stages: Stage 1 (5%), Stage 2 (55%), Stage 3 (5%), and Stage 4 (10%).
      – REM sleep is Stage 5 and normal adults spend 25% of their sleep in this stage.

    • This question is part of the following fields:

      • Neurosciences
      10.9
      Seconds
  • Question 5 - Which brain system enables the integration of emotional sensory information between the cortex...

    Incorrect

    • Which brain system enables the integration of emotional sensory information between the cortex and hypothalamus?

      Your Answer:

      Correct Answer: Papez circuit

      Explanation:

      In 1937, James Papez proposed a neural circuit that explained how emotional experiences occur in the brain. According to Papez, sensory messages related to emotional stimuli are first received by the thalamus, which then directs them to both the cortex (stream of thinking) and hypothalamus (stream of feeling). The cingulate cortex integrates this information from the hypothalamus and sensory cortex, leading to emotional experiences. The output via the hippocampus and hypothalamus allows cortical control of emotional responses. This circuit has since been reconceptualized as the limbic system.

      The medial longitudinal fasciculus carries fibres from cranial nerves III, IV and IV. The nucleus accumbens plays a major role in the reward circuit, while the somatosensory cortex is involved in processing pain. The basal ganglia are involved in voluntary motor control.

      Overall, the Papez circuit theory provides a framework for understanding the functional neuroanatomy of emotion. It highlights the importance of the limbic system in emotional experiences and the role of various brain regions in processing different aspects of emotional stimuli.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 6 - Which type of cells in the central nervous system are most vulnerable to...

    Incorrect

    • Which type of cells in the central nervous system are most vulnerable to HIV?

      Your Answer:

      Correct Answer: Microglia

      Explanation:

      The vulnerability of microglia to HIV infection is highest among all the cell types in the brain. This is because the CD4 and CCR5 receptors required for HIV cell entry are expressed in both parenchymal microglia and perivascular microglia/macrophages. Although there have been some reports of HIV infection in endothelial cells, neurons, and oligodendrocytes, it is generally accepted that such infections are rare and unlikely to play a significant role in HIV-related CNS disorders. Astrocytes are thought to be capable of only a limited form of HIV infection.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 7 - A 62-year-old man experiences a stroke caused by a ruptured berry aneurysm in...

    Incorrect

    • A 62-year-old man experiences a stroke caused by a ruptured berry aneurysm in the middle cerebral artery, resulting in damage to the temporal lobe. What tests would you anticipate to show abnormalities?

      Your Answer:

      Correct Answer: Copying intersecting pentagons

      Explanation:

      When the parietal lobe is not functioning properly, it can cause constructional apraxia. This condition makes it difficult for individuals to replicate the intersecting pentagons, which is a common cognitive test included in Folstein’s mini-mental state examination.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 8 - In which region of the brain are most dopamine neurons found? ...

    Incorrect

    • In which region of the brain are most dopamine neurons found?

      Your Answer:

      Correct Answer: Substantia nigra

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 9 - What is a common target for deep brain stimulation (DBS) in individuals with...

    Incorrect

    • What is a common target for deep brain stimulation (DBS) in individuals with Parkinson's disease?

      Your Answer:

      Correct Answer: Globus pallidus interna

      Explanation:

      DBS is primarily used to treat Parkinson’s disease by targeting the Globus pallidus interna and subthalamic nucleus. However, for treatment-resistant depression (TRD), the subcallosal cingulate was the first area investigated for DBS, while vagal nerve stimulation has also been used. Psychosurgical treatment for refractory OCD and TRD involves targeting the anterior limb of the internal capsule. Although the caudate nucleus is part of the basal ganglia and associated with Parkinson’s disease, it is not a primary target for DBS.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 10 - What is the closest estimate of the membrane potential of a cell at...

    Incorrect

    • What is the closest estimate of the membrane potential of a cell at rest?

      Your Answer:

      Correct Answer: -70 mV

      Explanation:

      Understanding Action Potentials in Neurons and Muscle Cells

      The membrane potential is a crucial aspect of cell physiology, and it exists across the plasma membrane of most cells. However, in neurons and muscle cells, this membrane potential can change over time. When a cell is not stimulated, it is in a resting state, and the inside of the cell is negatively charged compared to the outside. This resting membrane potential is typically around -70mV, and it is maintained by the Na/K pump, which maintains a high concentration of Na outside and K inside the cell.

      To trigger an action potential, the membrane potential must be raised to around -55mV. This can occur when a neurotransmitter binds to the postsynaptic neuron and opens some ion channels. Once the membrane potential reaches -55mV, a cascade of events is initiated, leading to the opening of a large number of Na channels and causing the cell to depolarize. As the membrane potential reaches around +40 mV, the Na channels close, and the K gates open, allowing K to flood out of the cell and causing the membrane potential to fall back down. This process is irreversible and is critical for the transmission of signals in neurons and the contraction of muscle cells.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 11 - Which imaging technique is not considered functional? ...

    Incorrect

    • Which imaging technique is not considered functional?

      Your Answer:

      Correct Answer: CT

      Explanation:

      Neuroimaging techniques can be divided into structural and functional types, although this distinction is becoming less clear as new techniques emerge. Structural techniques include computed tomography (CT) and magnetic resonance imaging (MRI), which use x-rays and magnetic fields, respectively, to produce images of the brain’s structure. Functional techniques, on the other hand, measure brain activity by detecting changes in blood flow of oxygen consumption. These include functional MRI (fMRI), emission tomography (PET and SPECT), perfusion MRI (pMRI), and magnetic resonance spectroscopy (MRS). Some techniques, such as diffusion tensor imaging (DTI), combine both structural and functional information to provide a more complete picture of the brain’s anatomy and function. DTI, for example, uses MRI to estimate the paths that water takes as it diffuses through white matter, allowing researchers to visualize white matter tracts.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 12 - Which one of these organs is not classified as a circumventricular organ? ...

    Incorrect

    • Which one of these organs is not classified as a circumventricular organ?

      Your Answer:

      Correct Answer: The olive

      Explanation:

      Understanding the Blood Brain Barrier

      The blood brain barrier (BBB) is a crucial component of the brain’s defense system against harmful chemicals and ion imbalances. It is a semi-permeable membrane formed by tight junctions of endothelial cells in the brain’s capillaries, which separates the blood from the cerebrospinal fluid. However, certain areas of the BBB, known as circumventricular organs, are fenestrated to allow neurosecretory products to enter the blood.

      When it comes to MRCPsych questions, the focus is on the following aspects of the BBB: the tight junctions between endothelial cells, the ease with which lipid-soluble molecules pass through compared to water-soluble ones, the difficulty large and highly charged molecules face in passing through, the increased permeability of the BBB during inflammation, and the theoretical ability of nasally administered drugs to bypass the BBB.

      It is important to remember the specific circumventricular organs where the BBB is fenestrated, including the posterior pituitary and the area postrema. Understanding the BBB’s function and characteristics is essential for medical professionals to diagnose and treat neurological disorders effectively.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 13 - What condition is identified by the combination of Parkinsonism, cerebellar ataxia, and autonomic...

    Incorrect

    • What condition is identified by the combination of Parkinsonism, cerebellar ataxia, and autonomic failure?

      Your Answer:

      Correct Answer: Multisystem atrophy

      Explanation:

      Multisystem Atrophy: A Parkinson Plus Syndrome

      Multisystem atrophy is a type of Parkinson plus syndrome that is characterized by three main features: Parkinsonism, autonomic failure, and cerebellar ataxia. It can present in three different ways, including Shy-Drager Syndrome, Striatonigral degeneration, and Olivopontocerebellar atrophy, each with varying degrees of the three main features.

      Macroscopic features of multisystem atrophy include pallor of the substantia nigra, greenish discoloration and atrophy of the putamen, and cerebellar atrophy. Microscopic features include the presence of Papp-Lantos bodies, which are alpha-synuclein inclusions found in oligodendrocytes in the substantia nigra, cerebellum, and basal ganglia.

      Overall, multisystem atrophy is a complex and debilitating condition that affects multiple systems in the body, leading to a range of symptoms and challenges for patients and their caregivers.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 14 - Which CNS histopathological characteristic is the most distinctive for prion diseases? ...

    Incorrect

    • Which CNS histopathological characteristic is the most distinctive for prion diseases?

      Your Answer:

      Correct Answer: Spongiform (vacuolation) change

      Explanation:

      The presence of spongiform (vacuolation) change is a highly specific indicator of prion diseases. While neuronal loss and gliosis are common in many CNS disorders, spongiform change is unique to prion diseases. This change is characterized by the appearance of vacuoles in the deep cortical layers, cerebellar cortex, of subcortical grey matter. Scar formation and acute immune responses are associated with reactive proliferation of astrocytes and microglia, respectively. In contrast, Alzheimer’s dementia is characterized by the presence of amyloid plaques.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 15 - What type of speech disorder is commonly associated with spasticity and would be...

    Incorrect

    • What type of speech disorder is commonly associated with spasticity and would be most likely to be observed in a patient?

      Your Answer:

      Correct Answer: Pseudobulbar palsy

      Explanation:

      Dysarthria is a speech disorder that affects the volume, rate, tone, of quality of spoken language. There are different types of dysarthria, each with its own set of features, associated conditions, and localisation. The types of dysarthria include spastic, flaccid, hypokinetic, hyperkinetic, and ataxic.

      Spastic dysarthria is characterised by explosive and forceful speech at a slow rate and is associated with conditions such as pseudobulbar palsy and spastic hemiplegia.

      Flaccid dysarthria, on the other hand, is characterised by a breathy, nasal voice and imprecise consonants and is associated with conditions such as myasthenia gravis.

      Hypokinetic dysarthria is characterised by slow, quiet speech with a tremor and is associated with conditions such as Parkinson’s disease.

      Hyperkinetic dysarthria is characterised by a variable rate, inappropriate stoppages, and a strained quality and is associated with conditions such as Huntington’s disease, Sydenham’s chorea, and tardive dyskinesia.

      Finally, ataxic dysarthria is characterised by rapid, monopitched, and slurred speech and is associated with conditions such as Friedreich’s ataxia and alcohol abuse. The localisation of each type of dysarthria varies, with spastic and flaccid dysarthria affecting the upper and lower motor neurons, respectively, and hypokinetic, hyperkinetic, and ataxic dysarthria affecting the extrapyramidal and cerebellar regions of the brain.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 16 - What is the neural pathway that links areas of the frontal lobe to...

    Incorrect

    • What is the neural pathway that links areas of the frontal lobe to areas of the temporal lobe within the same hemisphere?

      Your Answer:

      Correct Answer: Superior Longitudinal (arcuate) Fasciculus

      Explanation:

      White matter is the cabling that links different parts of the CNS together. There are three types of white matter cables: projection tracts, commissural tracts, and association tracts. Projection tracts connect higher centers of the brain with lower centers, commissural tracts connect the two hemispheres together, and association tracts connect regions of the same hemisphere. Some common tracts include the corticospinal tract, which connects the motor cortex to the brainstem and spinal cord, and the corpus callosum, which is the largest white matter fiber bundle connecting corresponding areas of cortex between the hemispheres. Other tracts include the cingulum, superior and inferior occipitofrontal fasciculi, and the superior and inferior longitudinal fasciculi.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 17 - A 70-year-old individual presents with a fluent dysphasia and inability to understand instructions....

    Incorrect

    • A 70-year-old individual presents with a fluent dysphasia and inability to understand instructions. What is the probable location of arterial blockage?

      Your Answer:

      Correct Answer: Inferior division of middle cerebral artery (dominant hemisphere)

      Explanation:

      Wernicke’s aphasia is caused by a blockage in the inferior division of the middle cerebral artery, which provides blood to the temporal cortex (specifically, the posterior superior temporal gyrus of ‘Wernicke’s area’). This type of aphasia is characterized by fluent speech, but with significant comprehension difficulties. On the other hand, Broca’s aphasia is considered a non-fluent expressive aphasia, resulting from damage to Brodmann’s area in the frontal lobe.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 18 - Which statement about variant CJD is accurate? ...

    Incorrect

    • Which statement about variant CJD is accurate?

      Your Answer:

      Correct Answer: It is associated with the pulvinar sign on the MRI

      Explanation:

      Creutzfeldt-Jakob Disease: Differences between vCJD and CJD

      Creutzfeldt-Jakob Disease (CJD) is a prion disease that includes scrapie, BSE, and Kuru. However, there are important differences between sporadic (also known as classic) CJD and variant CJD. The table below summarizes these differences.

      vCJD:
      – Longer duration from onset of symptoms to death (a year of more)
      – Presents with psychiatric and behavioral symptoms before neurological symptoms
      – MRI shows pulvinar sign
      – EEG shows generalized slowing
      – Originates from infected meat products
      – Affects younger people (age 25-30)

      CJD:
      – Shorter duration from onset of symptoms to death (a few months)
      – Presents with neurological symptoms
      – MRI shows bilateral anterior basal ganglia high signal
      – EEG shows biphasic and triphasic waves 1-2 per second
      – Originates from genetic mutation (bad luck)
      – Affects older people (age 55-65)

      Overall, understanding the differences between vCJD and CJD is important for diagnosis and treatment.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 19 - A 62-year-old man experiences a stroke caused by a ruptured berry aneurysm in...

    Incorrect

    • A 62-year-old man experiences a stroke caused by a ruptured berry aneurysm in the middle cerebral artery. What is the most sensitive test to assess the affected lobe?

      Your Answer:

      Correct Answer: Verbal fluency

      Explanation:

      Frontal lobe damage can be best detected through tests of verbal fluency, such as the FAS Verbal Fluency Test, as the anterior cerebral artery supplies the frontal lobes and medial aspects of the parietal and occipital lobes, which are responsible for this function.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 20 - What EEG alteration would be anticipated when a patient who is in a...

    Incorrect

    • What EEG alteration would be anticipated when a patient who is in a relaxed state with their eyes shut is instructed to open their eyes and read a text passage in front of them?

      Your Answer:

      Correct Answer: The bilateral disappearance of alpha waves

      Explanation:

      When someone is in a relaxed state with their eyes closed, alpha waves can be detected in the posterior regions of their head. However, these waves will disappear if the person becomes drowsy, concentrates on something, is stimulated, of fixates on a visual object. If the environment is dark, the alpha waves may still be present even with the eyes open.

      Electroencephalography

      Electroencephalography (EEG) is a clinical test that records the brain’s spontaneous electrical activity over a short period of time using multiple electrodes placed on the scalp. It is mainly used to rule out organic conditions and can help differentiate dementia from other disorders such as metabolic encephalopathies, CJD, herpes encephalitis, and non-convulsive status epilepticus. EEG can also distinguish possible psychotic episodes and acute confusional states from non-convulsive status epilepticus.

      Not all abnormal EEGs represent an underlying condition, and psychotropic medications can affect EEG findings. EEG abnormalities can also be triggered purposely by activation procedures such as hyperventilation, photic stimulation, certain drugs, and sleep deprivation.

      Specific waveforms are seen in an EEG, including delta, theta, alpha, sigma, beta, and gamma waves. Delta waves are found frontally in adults and posteriorly in children during slow wave sleep, and excessive amounts when awake may indicate pathology. Theta waves are generally seen in young children, drowsy and sleeping adults, and during meditation. Alpha waves are seen posteriorly when relaxed and when the eyes are closed, and are also seen in meditation. Sigma waves are bursts of oscillatory activity that occur in stage 2 sleep. Beta waves are seen frontally when busy of concentrating, and gamma waves are seen in advanced/very experienced meditators.

      Certain conditions are associated with specific EEG changes, such as nonspecific slowing in early CJD, low voltage EEG in Huntington’s, diffuse slowing in encephalopathy, and reduced alpha and beta with increased delta and theta in Alzheimer’s.

      Common epileptiform patterns include spikes, spike/sharp waves, and spike-waves. Medications can have important effects on EEG findings, with clozapine decreasing alpha and increasing delta and theta, lithium increasing all waveforms, lamotrigine decreasing all waveforms, and valproate having inconclusive effects on delta and theta and increasing beta.

      Overall, EEG is a useful tool in clinical contexts for ruling out organic conditions and differentiating between various disorders.

    • This question is part of the following fields:

      • Neurosciences
      0
      Seconds
  • Question 21 - How can association tracts be defined in relation to white matter? ...

    Incorrect

    • How can association tracts be defined in relation to white matter?

      Your Answer:

      Correct Answer: Cingulum

      Explanation:

      White matter is the cabling that links different parts of the CNS together. There are three types of white matter cables: projection tracts, commissural tracts, and association tracts. Projection tracts connect higher centers of the brain with lower centers, commissural tracts connect the two hemispheres together, and association tracts connect regions of the same hemisphere. Some common tracts include the corticospinal tract, which connects the motor cortex to the brainstem and spinal cord, and the corpus callosum, which is the largest white matter fiber bundle connecting corresponding areas of cortex between the hemispheres. Other tracts include the cingulum, superior and inferior occipitofrontal fasciculi, and the superior and inferior longitudinal fasciculi.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 22 - Which factor is most closely linked to the development of dementia in individuals...

    Incorrect

    • Which factor is most closely linked to the development of dementia in individuals with HIV?

      Your Answer:

      Correct Answer: Monocyte infiltration and microglial activation

      Explanation:

      The strongest association with HIV dementia is the infiltration of monocytes and activation of microglia in the brain. While the presence of HIV encephalopathy is somewhat linked to HIV associated dementia, the extent of monocyte infiltration and microglial activation is the best indicator of AIDS dementia. Microglia can cause damage to neurons by releasing oxidative radicals, nitric oxide, and cytokines. The correlation between viral load and HAD is not significant. Astrocytes have limited susceptibility to HIV infection, and neuronal infection is rare and unlikely to have a significant impact on HIV-related CNS disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 23 - What is the stage of sleep that is identified by hypnic jerks and...

    Incorrect

    • What is the stage of sleep that is identified by hypnic jerks and theta waves on the EEG?

      Your Answer:

      Correct Answer: Stage I

      Explanation:

      Sleep Stages

      Sleep is divided into two distinct states called rapid eye movement (REM) and non-rapid eye movement (NREM). NREM is subdivided into four stages.

      Sleep stage
      Approx % of time spent in stage
      EEG findings
      Comment

      I
      5%
      Theta waves (4-7 Hz)
      The dozing off stage. Characterized by hypnic jerks: spontaneous myoclonic contractions associated with a sensation of twitching of falling.

      II
      45%
      Theta waves, K complexes and sleep spindles (short bursts of 12-14 Hz activity)
      Body enters a more subdued state including a drop in temperature, relaxed muscles, and slowed breathing and heart rate. At the same time, brain waves show a new pattern and eye movement stops.

      III
      15%
      Delta waves (0-4 Hz)
      Deepest stage of sleep (high waking threshold). The length of stage 3 decreases over the course of the night.

      IV
      15%
      Mixed, predominantly beta
      High dream activity.

      The percentage of REM sleep decreases with age.

      It takes the average person 15-20 minutes to fall asleep, this is called sleep latency (characterised by the onset of stage I sleep). Once asleep one descends through stages I-II and then III-IV (deep stages). After about 90 minutes of sleep one enters REM. The rest of the sleep comprises of cycles through the stages. As the sleep progresses the periods of REM become greater and the periods of NREM become less. During an average night’s sleep one spends 25% of the sleep in REM and 75% in NREM.

      REM sleep has certain characteristics that separate it from NREM

      Characteristics of REM sleep

      – Autonomic instability (variability in heart rate, respiratory rate, and BP)
      – Loss of muscle tone
      – Dreaming
      – Rapid eye movements
      – Penile erection

      Deafness:

      (No information provided on deafness in relation to sleep stages)

    • This question is part of the following fields:

      • Neurosciences
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  • Question 24 - Which of the following neuropathological findings in young individuals with HIV infection is...

    Incorrect

    • Which of the following neuropathological findings in young individuals with HIV infection is also seen in the brains of drug users who do not have HIV?

      Your Answer:

      Correct Answer: Axonal damage

      Explanation:

      Axonal damage is present in the brains of both individuals with early HIV infection and those who do not have HIV but use drugs. Pre-symptomatic HIV infection has been linked to various neurological changes, including lymphocytic leptomeningitis, perivascular lymphocytic cuffing, and infiltration of T and B lymphocytes in brain tissue, as well as subtle gliosis and microglial activation. While axonal damage has been observed in early HIV infection, it may also be caused by factors such as inflammation, trauma, and hypoxia.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 25 - If a man experiences a severe road traffic accident resulting in substantial damage...

    Incorrect

    • If a man experiences a severe road traffic accident resulting in substantial damage to his frontal lobe, what symptoms would you anticipate him to exhibit?

      Your Answer:

      Correct Answer: Contralateral hemiplegia

      Explanation:

      Cerebral Dysfunction: Lobe-Specific Features

      When the brain experiences dysfunction, it can manifest in various ways depending on the affected lobe. In the frontal lobe, dysfunction can lead to contralateral hemiplegia, impaired problem solving, disinhibition, lack of initiative, Broca’s aphasia, and agraphia (dominant). The temporal lobe dysfunction can result in Wernicke’s aphasia (dominant), homonymous upper quadrantanopia, and auditory agnosia (non-dominant). On the other hand, the non-dominant parietal lobe dysfunction can lead to anosognosia, dressing apraxia, spatial neglect, and constructional apraxia. Meanwhile, the dominant parietal lobe dysfunction can result in Gerstmann’s syndrome. Lastly, occipital lobe dysfunction can lead to visual agnosia, visual illusions, and contralateral homonymous hemianopia.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 26 - Which cranial nerve is solely responsible for sensory functions? ...

    Incorrect

    • Which cranial nerve is solely responsible for sensory functions?

      Your Answer:

      Correct Answer: Vestibulocochlear

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 27 - What is included in the basal ganglia? ...

    Incorrect

    • What is included in the basal ganglia?

      Your Answer:

      Correct Answer: Putamen

      Explanation:

      The Basal Ganglia: Functions and Disorders

      The basal ganglia are a group of subcortical structures that play a crucial role in controlling movement and some cognitive processes. The components of the basal ganglia include the striatum (caudate, putamen, nucleus accumbens), subthalamic nucleus, globus pallidus, and substantia nigra (divided into pars compacta and pars reticulata). The putamen and globus pallidus are collectively referred to as the lenticular nucleus.

      The basal ganglia are connected in a complex loop, with the cortex projecting to the striatum, the striatum to the internal segment of the globus pallidus, the internal segment of the globus pallidus to the thalamus, and the thalamus back to the cortex. This loop is responsible for regulating movement and cognitive processes.

      However, problems with the basal ganglia can lead to several conditions. Huntington’s chorea is caused by degeneration of the caudate nucleus, while Wilson’s disease is characterized by copper deposition in the basal ganglia. Parkinson’s disease is associated with degeneration of the substantia nigra, and hemiballism results from damage to the subthalamic nucleus.

      In summary, the basal ganglia are a crucial part of the brain that regulate movement and some cognitive processes. Disorders of the basal ganglia can lead to significant neurological conditions that affect movement and other functions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 28 - In which part of the body is the nucleus of Meynert situated? ...

    Incorrect

    • In which part of the body is the nucleus of Meynert situated?

      Your Answer:

      Correct Answer: Substantia innominata

      Explanation:

      The nucleus of Meynert, located in the substantia innominata of the basal forebrain beneath the thalamus and lentiform nucleus, is a cluster of neurons that serves as the primary source of acetylcholine in the brain. In Alzheimer’s disease, the nucleus of Meynert undergoes atrophy, resulting in a decrease in acetylcholine levels. This explains why cholinesterase inhibitors, which increase acetylcholine levels, are effective in treating Alzheimer’s.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 29 - A hoarse voice and difficulty swallowing (dysphagia) are symptoms of a lesion in...

    Incorrect

    • A hoarse voice and difficulty swallowing (dysphagia) are symptoms of a lesion in which cranial nerve?

      Your Answer:

      Correct Answer: Vagus

      Explanation:

      Lesions of the vagus nerve commonly result in the following symptoms: a raspy of weak voice, difficulty swallowing, absence of the gag reflex, deviation of the uvula away from the affected side, and an inability to elevate the palate.

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 30 - The histopathological findings from a post-mortem of an older man with long standing...

    Incorrect

    • The histopathological findings from a post-mortem of an older man with long standing memory difficulties reveals neuronal and glial tau aggregation in addition to pronounced atrophy of the frontal and temporal lobes.

      What is the most probable diagnosis for an elderly man with these histopathological findings?

      Your Answer:

      Correct Answer: Pick's disease

      Explanation:

      Alzheimer’s disease is not characterized by significant frontal lobe atrophy, but rather by early medial temporal lobe atrophy (MTA) on MRI, particularly in the hippocampus, entorhinal cortex, amygdala, and parahippocampus. In contrast, frontotemporal lobar degeneration (FTLD) typically affects the frontal and anterior temporal lobes in behavioral variant frontotemporal dementia (bvFTD of Pick’s disease), the left anterior temporal lobe in semantic dementia (SD), and the left perisylvian fissure in progressive nonfluent aphasia (PNFA).

      Frontotemporal Lobar Degeneration (FTLD) is a pathological term that refers to a group of neurodegenerative disorders that affect the frontal and temporal lobes of the brain. FTLD is classified into several subtypes based on the main protein component of neuronal and glial abnormal inclusions and their distribution. The three main proteins associated with FTLD are Tau, TDP-43, and FUS. Each FTD clinical phenotype has been associated with different proportions of these proteins. Macroscopic changes in FTLD include atrophy of the frontal and temporal lobes, with focal gyral atrophy that resembles knives. Microscopic changes in FTLD-Tau include neuronal and glial tau aggregation, with further sub-classification based on the existence of different isoforms of tau protein. FTLD-TDP is characterized by cytoplasmic inclusions of TDP-43 in neurons, while FTLD-FUS is characterized by cytoplasmic inclusions of FUS.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 31 - Which cognitive function is thought to be essential for the ventromedial prefrontal cortex?...

    Incorrect

    • Which cognitive function is thought to be essential for the ventromedial prefrontal cortex?

      Your Answer:

      Correct Answer: Moral judgement

      Explanation:

      The Neuroscience of Morality

      Morality is a process that involves both instinctive feelings and rational judgement. The ventromedial prefrontal cortex (PFC) is responsible for the emotional baseline, while the dorsolateral PFC is involved in cognitive control and problem solving. Studies have shown that the ventromedial PFC is activated during the solving of moral problems, particularly when responding to emotionally charged scenarios. On the other hand, the dorsolateral PFC is involved in tamping down our innate, reactionary moral system. These findings suggest that morality is a dual process event that involves both emotional and cognitive systems in the brain.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 32 - Which neuroimaging technique measures the amount of oxygenated hemoglobin in the blood? ...

    Incorrect

    • Which neuroimaging technique measures the amount of oxygenated hemoglobin in the blood?

      Your Answer:

      Correct Answer: Functional magnetic resonance imaging (fMRI)

      Explanation:

      Functional Imaging Techniques

      Functional imaging techniques are used to study brain activity by detecting changes in blood flow and oxygenation levels. One such technique is functional magnetic resonance imaging (fMRI), which measures the concentration of oxygenated haemoglobin in the blood. When neural activity increases in a specific area of the brain, blood flow to that area increases, leading to a higher concentration of haemoglobin.

      Magnetic resonance imaging (MRI) is another technique that uses magnetic fields to create images of the brain’s structure. Magnetic resonance spectroscopy (MRS) is a related technique that can detect several odd-numbered nuclei.

      To obtain a more accurate anatomical location for functional information, single photon emission computed tomography (SPECT) and positron emission tomography (PET) are used. SPECT and PET both provide information about brain activity by detecting the emission of particles. However, SPECT emits a single particle, while PET emits two particles. These techniques are useful for studying brain function in both healthy individuals and those with neurological disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 33 - What street drug inhibits the monoamine transporter SERT? ...

    Incorrect

    • What street drug inhibits the monoamine transporter SERT?

      Your Answer:

      Correct Answer: Amphetamine

      Explanation:

      Cannabis attaches to cannabinoid receptors, while heroin acts as an opioid agonist and alters the function of dopamine.

      Serotonin: Synthesis and Breakdown

      Serotonin, also known as 5-Hydroxytryptamine (5-HT), is synthesized in the central nervous system (CNS) in the raphe nuclei located in the brainstem, as well as in the gastrointestinal (GI) tract in enterochromaffin cells. The amino acid L-tryptophan, obtained from the diet, is used to synthesize serotonin. L-tryptophan can cross the blood-brain barrier, but serotonin cannot.

      The transformation of L-tryptophan into serotonin involves two steps. First, hydroxylation to 5-hydroxytryptophan is catalyzed by tryptophan hydroxylase. Second, decarboxylation of 5-hydroxytryptophan to serotonin (5-hydroxytryptamine) is catalyzed by L-aromatic amino acid decarboxylase.

      Serotonin is taken up from the synapse by a monoamine transporter (SERT). Substances that block this transporter include MDMA, amphetamine, cocaine, TCAs, and SSRIs. Serotonin is broken down by monoamine oxidase (MAO) and then by aldehyde dehydrogenase to 5-Hydroxyindoleacetic acid (5-HIAA).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 34 - What is another term for 'intrinsic activity' when referring to drug/receptor interactions? ...

    Incorrect

    • What is another term for 'intrinsic activity' when referring to drug/receptor interactions?

      Your Answer:

      Correct Answer: Efficacy

      Explanation:

      Efficacy, also referred to as intrinsic activity, pertains to a drug’s capacity to produce a reaction upon binding to a receptor.

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 35 - In which type of condition of disease are Hirano bodies commonly observed? ...

    Incorrect

    • In which type of condition of disease are Hirano bodies commonly observed?

      Your Answer:

      Correct Answer: Hippocampus

      Explanation:

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 36 - A 65-year-old individual reports a sudden inability to chew food and upon examination,...

    Incorrect

    • A 65-year-old individual reports a sudden inability to chew food and upon examination, displays weakened masseter muscles. What nerve damage do you suspect?

      Your Answer:

      Correct Answer: Cranial nerve V

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 37 - From where does the nerve that originates in the medulla oblongata come? ...

    Incorrect

    • From where does the nerve that originates in the medulla oblongata come?

      Your Answer:

      Correct Answer: Vagus

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 38 - From which amino acid is serotonin synthesized? ...

    Incorrect

    • From which amino acid is serotonin synthesized?

      Your Answer:

      Correct Answer: Tryptophan

      Explanation:

      Serotonin: Synthesis and Breakdown

      Serotonin, also known as 5-Hydroxytryptamine (5-HT), is synthesized in the central nervous system (CNS) in the raphe nuclei located in the brainstem, as well as in the gastrointestinal (GI) tract in enterochromaffin cells. The amino acid L-tryptophan, obtained from the diet, is used to synthesize serotonin. L-tryptophan can cross the blood-brain barrier, but serotonin cannot.

      The transformation of L-tryptophan into serotonin involves two steps. First, hydroxylation to 5-hydroxytryptophan is catalyzed by tryptophan hydroxylase. Second, decarboxylation of 5-hydroxytryptophan to serotonin (5-hydroxytryptamine) is catalyzed by L-aromatic amino acid decarboxylase.

      Serotonin is taken up from the synapse by a monoamine transporter (SERT). Substances that block this transporter include MDMA, amphetamine, cocaine, TCAs, and SSRIs. Serotonin is broken down by monoamine oxidase (MAO) and then by aldehyde dehydrogenase to 5-Hydroxyindoleacetic acid (5-HIAA).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 39 - What is the name of the bundle of association fibers that connects the...

    Incorrect

    • What is the name of the bundle of association fibers that connects the frontal and temporal lobes and is crucial for language repetition?

      Your Answer:

      Correct Answer: Arcuate fasciculus

      Explanation:

      Association fibres refer to axons that link different cortical areas within the same hemisphere of the brain. The middle longitudinal fasciculus is a white matter tract that connects the inferior parietal lobule to the temporal cortices. The uncinate fasciculus is a relatively short pathway that connects the anterior temporal areas to the inferior frontal areas. The inferior longitudinal fasciculus and inferior fronto-occipital fasciculus fibre pathways are believed to connect the occipital cortices to the anterior temporal and inferior frontal cortices (note that the inferior fronto-occipital fasciculus pathway is also known as the inferior occipitofrontal fasciculus). The cingulum is a group of white matter fibres that extend from the cingulate gyrus to the entorhinal cortex, facilitating communication between different parts of the limbic system.

      Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 40 - A 65-year-old woman passed away unexpectedly due to a heart attack. She had...

    Incorrect

    • A 65-year-old woman passed away unexpectedly due to a heart attack. She had been experiencing significant difficulties with her short-term memory, which had been impacting her daily activities. Upon conducting an autopsy of her brain, it was discovered that she had widespread cerebral atrophy, as well as numerous neurofibrillary tangles and neuritic plaques. What is the probable diagnosis?

      Your Answer:

      Correct Answer: Alzheimer's disease

      Explanation:

      Neurofibrillary tangles and neuritic (senile) plaques are commonly found in the brains of elderly individuals, but they are not present in Lewy body dementia. Pick’s disease is characterized by the presence of Pick’s bodies and knife blade atrophy. Creutzfeldt-Jakob disease (CJD) is identified by the spongy appearance of the grey matter in the cerebral cortex due to multiple vacuoles. If an individual experiences short-term memory problems that affect their daily life, it may indicate the presence of dementia. Alzheimer’s disease is characterized by extensive tangles and plaques in the brain.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 41 - What triggers the release of neurotransmitter from presynaptic vesicles into the synaptic cleft?...

    Incorrect

    • What triggers the release of neurotransmitter from presynaptic vesicles into the synaptic cleft?

      Your Answer:

      Correct Answer: Calcium

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 42 - What hormone is secreted by the posterior pituitary gland? ...

    Incorrect

    • What hormone is secreted by the posterior pituitary gland?

      Your Answer:

      Correct Answer: Antidiuretic hormone

      Explanation:

      The hormone ADH (also known as vasopressin) is released from the posterior pituitary gland and promotes water retention and increased blood pressure by constricting arterioles. Conversely, the hormones ACTH, growth hormone, luteinizing hormone, and thyroid stimulating hormone are all released from the anterior pituitary gland and have various effects on the body, such as stimulating hormone production in the adrenal glands, promoting bone and muscle growth, regulating sex gland function, and stimulating the release of thyroxine.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 43 - What is a true statement about the neocortex? ...

    Incorrect

    • What is a true statement about the neocortex?

      Your Answer:

      Correct Answer: It contains both pyramidal and nonpyramidal cells

      Explanation:

      The Cerebral Cortex and Neocortex

      The cerebral cortex is the outermost layer of the cerebral hemispheres and is composed of three parts: the archicortex, paleocortex, and neocortex. The neocortex accounts for 90% of the cortex and is involved in higher functions such as thought and language. It is divided into 6-7 layers, with two main cell types: pyramidal cells and nonpyramidal cells. The surface of the neocortex is divided into separate areas, each given a number by Brodmann (e.g. Brodmann’s area 17 is the primary visual cortex). The surface is folded to increase surface area, with grooves called sulci and ridges called gyri. The neocortex is responsible for higher cognitive functions and is essential for human consciousness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 44 - What is the cause of Kluver-Bucy syndrome, which occurs as a result of...

    Incorrect

    • What is the cause of Kluver-Bucy syndrome, which occurs as a result of damage to which part of the brain?

      Your Answer:

      Correct Answer: Temporal lobe

      Explanation:

      Kluver-Bucy syndrome is a neurological disorder that results from dysfunction in both the right and left medial temporal lobes of the brain. This condition is characterized by a range of symptoms, including docility, altered dietary habits, hyperorality, and changes in sexual behavior. Additionally, individuals with Kluver-Bucy syndrome may experience visual agnosia, which is a condition that impairs their ability to recognize and interpret visual stimuli.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 45 - You are asked to review a child on the ward who the staff...

    Incorrect

    • You are asked to review a child on the ward who the staff noted had a sudden and brief (one minute) episode whereby they went into what they described as a trance-like state. During this time the child was unresponsive and was seen to be picking aimlessly at their clothes. Following this episode the child did not recall being unresponsive but did report that before this happened they felt a strange sense of unfamiliarity. Which of the following epilepsy types would you most suspect?:

      Your Answer:

      Correct Answer: Complex partial seizure

      Explanation:

      The indication of a complex partial seizure is strongly implied by the absence of knowledge regarding aura.

      Epilepsy and Aura

      An aura is a subjective sensation that is a type of simple partial seizure. It typically lasts only a few seconds and can help identify the site of cortical onset. There are eight recognized types of auras, including somatosensory, visual, auditory, gustatory, olfactory, autonomic, abdominal, and psychic.

      In about 80% of cases, auras precede temporal lobe seizures. The most common auras in these seizures are abdominal and psychic, which can cause a rising epigastric sensation of feelings of fear, déjà vu, of jamais vu. Parietal lobe seizures may begin with a contralateral sensation, usually of the positive type, such as an electrical sensation of tingling. Occipital lobe seizures may begin with contralateral visual changes, such as colored lines, spots, of shapes, of even a loss of vision. Temporal-parietal-occipital seizures may produce more formed auras.

      Complex partial seizures are defined by impairment of consciousness, which means decreased responsiveness and awareness of oneself and surroundings. During a complex partial seizure, a patient is unresponsive and does not remember events that occurred.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 46 - Which statement about acetylcholine is incorrect? ...

    Incorrect

    • Which statement about acetylcholine is incorrect?

      Your Answer:

      Correct Answer: Nicotinic receptors are also stimulated by muscarine

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 47 - What is a true statement about Anton-Babinski syndrome? ...

    Incorrect

    • What is a true statement about Anton-Babinski syndrome?

      Your Answer:

      Correct Answer: Confabulation is a characteristic feature

      Explanation:

      Anton’s syndrome, also known as Anton-Babinski syndrome, is a condition that results from damage to the occipital lobe. People with this syndrome are cortically blind, but they are not aware of it and deny having any problem, a condition known as anosognosia. They may start falling over furniture as they cannot see, but they believe they can still see and describe their surroundings in detail, even though their descriptions are incorrect (confabulation). This syndrome is characterized by a lack of awareness of visual impairment, which can lead to significant difficulties in daily life.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 48 - Which process breaks down dopamine? ...

    Incorrect

    • Which process breaks down dopamine?

      Your Answer:

      Correct Answer: Monoamine oxidase

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 49 - What percentage of individuals with Autism exhibit the following condition? ...

    Incorrect

    • What percentage of individuals with Autism exhibit the following condition?

      Your Answer:

      Correct Answer: Macrocephaly

      Explanation:

      Autism and Macrocephaly: A Common Neurobiological Finding

      Macrocephaly, of an abnormally large head circumference, is a common occurrence in individuals with idiopathic autism, with approximately 20% of individuals with autism exhibiting this trait (Fombonne, 1999). This finding has been replicated in numerous studies and is considered one of the most consistent neurobiological findings in autism. However, it is important to note that macrocephaly is typically not present at birth but rather develops during childhood.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 50 - Which of the options below is not classified as a type of motor...

    Incorrect

    • Which of the options below is not classified as a type of motor neuron disease?

      Your Answer:

      Correct Answer: Multisystem atrophy

      Explanation:

      Motor neuron Disease: A Progressive Neurodegenerative Condition

      Motor neuron Disease (MND) is a condition that progressively damages the upper and lower motor neurons. This damage leads to muscle weakness and wasting, resulting in a loss of mobility in the limbs, as well as difficulties with speech, swallowing, and breathing. MND can be classified into four main types, including Amyotrophic lateral sclerosis, Progressive bulbar palsy, Progressive muscular atrophy, and Primary lateral sclerosis.

      Macroscopic pathological features of MND include atrophy of the precentral gyrus and frontotemporal regions, thinning of the spinal cord, and atrophic anterior nerve roots. Microscopic changes involve the loss of motor neurons from the ventral horn of the spinal cord and lower brainstem. MND is a devastating condition that currently has no cure, and treatment is focused on managing symptoms and improving quality of life for those affected.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 51 - Which of the following is classified as a large molecule neurotransmitter? ...

    Incorrect

    • Which of the following is classified as a large molecule neurotransmitter?

      Your Answer:

      Correct Answer: Oxytocin

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 52 - The patient's complaint of being unable to identify objects in their hand without...

    Incorrect

    • The patient's complaint of being unable to identify objects in their hand without visual confirmation is an instance of what?

      Your Answer:

      Correct Answer: Astereognosia

      Explanation:

      Agnosia is a condition where a person loses the ability to recognize objects, persons, sounds, shapes, of smells, despite having no significant memory loss of defective senses. There are different types of agnosia, such as prosopagnosia (inability to recognize familiar faces), anosognosia (inability to recognize one’s own condition/illness), autotopagnosia (inability to orient parts of the body), phonagnosia (inability to recognize familiar voices), simultanagnosia (inability to appreciate two objects in the visual field at the same time), and astereoagnosia (inability to recognize objects by touch).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 53 - What are the consequences of damage to the arcuate fasciculus? ...

    Incorrect

    • What are the consequences of damage to the arcuate fasciculus?

      Your Answer:

      Correct Answer: Conduction aphasia

      Explanation:

      Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 54 - What is the condition that is identified by the presence of Papp-Lantos bodies?...

    Incorrect

    • What is the condition that is identified by the presence of Papp-Lantos bodies?

      Your Answer:

      Correct Answer: Multisystem atrophy

      Explanation:

      Multisystem Atrophy: A Parkinson Plus Syndrome

      Multisystem atrophy is a type of Parkinson plus syndrome that is characterized by three main features: Parkinsonism, autonomic failure, and cerebellar ataxia. It can present in three different ways, including Shy-Drager Syndrome, Striatonigral degeneration, and Olivopontocerebellar atrophy, each with varying degrees of the three main features.

      Macroscopic features of multisystem atrophy include pallor of the substantia nigra, greenish discoloration and atrophy of the putamen, and cerebellar atrophy. Microscopic features include the presence of Papp-Lantos bodies, which are alpha-synuclein inclusions found in oligodendrocytes in the substantia nigra, cerebellum, and basal ganglia.

      Overall, multisystem atrophy is a complex and debilitating condition that affects multiple systems in the body, leading to a range of symptoms and challenges for patients and their caregivers.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 55 - What type of lesion is most likely to cause bitemporal hemianopia? ...

    Incorrect

    • What type of lesion is most likely to cause bitemporal hemianopia?

      Your Answer:

      Correct Answer: Pituitary tumour

      Explanation:

      Bitemporal hemianopia is a condition in which an individual experiences a loss of vision in the outer (temporal of lateral) half of both their left and right visual fields. This condition is typically caused by damage to the optic chiasm.

      Cerebral Dysfunction: Lobe-Specific Features

      When the brain experiences dysfunction, it can manifest in various ways depending on the affected lobe. In the frontal lobe, dysfunction can lead to contralateral hemiplegia, impaired problem solving, disinhibition, lack of initiative, Broca’s aphasia, and agraphia (dominant). The temporal lobe dysfunction can result in Wernicke’s aphasia (dominant), homonymous upper quadrantanopia, and auditory agnosia (non-dominant). On the other hand, the non-dominant parietal lobe dysfunction can lead to anosognosia, dressing apraxia, spatial neglect, and constructional apraxia. Meanwhile, the dominant parietal lobe dysfunction can result in Gerstmann’s syndrome. Lastly, occipital lobe dysfunction can lead to visual agnosia, visual illusions, and contralateral homonymous hemianopia.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 56 - Which of the following does not align with a diagnosis of frontotemporal lobar...

    Incorrect

    • Which of the following does not align with a diagnosis of frontotemporal lobar degeneration?

      Your Answer:

      Correct Answer: Pronounced parietal lobe atrophy

      Explanation:

      Frontotemporal lobar degeneration results in the specific shrinking of the frontal and temporal lobes.

      Frontotemporal Lobar Degeneration (FTLD) is a pathological term that refers to a group of neurodegenerative disorders that affect the frontal and temporal lobes of the brain. FTLD is classified into several subtypes based on the main protein component of neuronal and glial abnormal inclusions and their distribution. The three main proteins associated with FTLD are Tau, TDP-43, and FUS. Each FTD clinical phenotype has been associated with different proportions of these proteins. Macroscopic changes in FTLD include atrophy of the frontal and temporal lobes, with focal gyral atrophy that resembles knives. Microscopic changes in FTLD-Tau include neuronal and glial tau aggregation, with further sub-classification based on the existence of different isoforms of tau protein. FTLD-TDP is characterized by cytoplasmic inclusions of TDP-43 in neurons, while FTLD-FUS is characterized by cytoplasmic inclusions of FUS.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 57 - From which region is the largest amount of norepinephrine released? ...

    Incorrect

    • From which region is the largest amount of norepinephrine released?

      Your Answer:

      Correct Answer: Locus coeruleus

      Explanation:

      Norepinephrine: Synthesis, Release, and Breakdown

      Norepinephrine is synthesized from tyrosine through a series of enzymatic reactions. The first step involves the conversion of tyrosine to L-DOPA by tyrosine hydroxylase. L-DOPA is then converted to dopamine by DOPA decarboxylase. Dopamine is further converted to norepinephrine by dopamine beta-hydroxylase. Finally, norepinephrine is converted to epinephrine by phenylethanolamine-N-methyltransferase.

      The primary site of norepinephrine release is the locus coeruleus, also known as the blue spot, which is located in the pons. Once released, norepinephrine is broken down by two enzymes: catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). These enzymes play a crucial role in regulating the levels of norepinephrine in the body.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 58 - What is the most probable outcome of damage to Broca's area? ...

    Incorrect

    • What is the most probable outcome of damage to Broca's area?

      Your Answer:

      Correct Answer: Non-fluent aphasia

      Explanation:

      Broca’s and Wernicke’s are two types of expressive dysphasia, which is characterized by difficulty producing speech despite intact comprehension. Dysarthria is a type of expressive dysphasia caused by damage to the speech production apparatus, while Broca’s aphasia is caused by damage to the area of the brain responsible for speech production, specifically Broca’s area located in Brodmann areas 44 and 45. On the other hand, Wernicke’s aphasia is a type of receptive of fluent aphasia caused by damage to the comprehension of speech, while the actual production of speech remains normal. Wernicke’s area is located in the posterior part of the superior temporal gyrus in the dominant hemisphere, within Brodmann area 22.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 59 - An agitated elderly patient requires restraint. Following the restraint, your examination of the...

    Incorrect

    • An agitated elderly patient requires restraint. Following the restraint, your examination of the patient reveals an inability to shrug the shoulders. Which nerve is most likely to have been damaged?

      Accessory

      91%

      Hypoglossal

      4%

      Abducent

      4%

      Oculomotor

      0%

      Glossopharyngeal

      1%

      This elderly patient has most likely suffered a traumatic injury to the accessory nerve.

      Your Answer:

      Correct Answer: Accessory

      Explanation:

      It is probable that this individual has experienced a traumatic injury affecting the accessory nerve.

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 60 - Disinhibition is most likely to occur as a result of dysfunction in which...

    Incorrect

    • Disinhibition is most likely to occur as a result of dysfunction in which of the following regions?

      Your Answer:

      Correct Answer: Right frontal lobe

      Explanation:

      Psychiatric and behavioral disturbances in individuals with frontal lobe lesions show a pattern of lateralization. Lesions in the left hemisphere are more commonly linked to depression, especially if they affect the prefrontal cortex’s dorsolateral region. Conversely, lesions in the right hemisphere are linked to impulsivity, disinhibition, and aggression.

      Cerebral Dysfunction: Lobe-Specific Features

      When the brain experiences dysfunction, it can manifest in various ways depending on the affected lobe. In the frontal lobe, dysfunction can lead to contralateral hemiplegia, impaired problem solving, disinhibition, lack of initiative, Broca’s aphasia, and agraphia (dominant). The temporal lobe dysfunction can result in Wernicke’s aphasia (dominant), homonymous upper quadrantanopia, and auditory agnosia (non-dominant). On the other hand, the non-dominant parietal lobe dysfunction can lead to anosognosia, dressing apraxia, spatial neglect, and constructional apraxia. Meanwhile, the dominant parietal lobe dysfunction can result in Gerstmann’s syndrome. Lastly, occipital lobe dysfunction can lead to visual agnosia, visual illusions, and contralateral homonymous hemianopia.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 61 - Which of the following is categorized as a projection tract in relation to...

    Incorrect

    • Which of the following is categorized as a projection tract in relation to white matter?

      Your Answer:

      Correct Answer: Geniculocalcarine tract

      Explanation:

      White matter is the cabling that links different parts of the CNS together. There are three types of white matter cables: projection tracts, commissural tracts, and association tracts. Projection tracts connect higher centers of the brain with lower centers, commissural tracts connect the two hemispheres together, and association tracts connect regions of the same hemisphere. Some common tracts include the corticospinal tract, which connects the motor cortex to the brainstem and spinal cord, and the corpus callosum, which is the largest white matter fiber bundle connecting corresponding areas of cortex between the hemispheres. Other tracts include the cingulum, superior and inferior occipitofrontal fasciculi, and the superior and inferior longitudinal fasciculi.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 62 - From which part of the embryonic brain does the cerebellum originate? ...

    Incorrect

    • From which part of the embryonic brain does the cerebellum originate?

      Your Answer:

      Correct Answer: Metencephalon

      Explanation:

      Development of the cerebellum commences from the metencephalon in the sixth week.

      Neurodevelopment: Understanding Brain Development

      The development of the central nervous system begins with the neuroectoderm, a specialized region of ectoderm. The embryonic brain is divided into three areas: the forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon). The prosencephalon further divides into the telencephalon and diencephalon, while the hindbrain subdivides into the metencephalon and myelencephalon.

      The telencephalon, of cerebrum, consists of the cerebral cortex, underlying white matter, and the basal ganglia. The diencephalon includes the prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum. The mesencephalon comprises the tectum, tegmentum, ventricular mesocoelia, cerebral peduncles, and several nuclei and fasciculi.

      The rhombencephalon includes the medulla, pons, and cerebellum, which can be subdivided into a variable number of transversal swellings called rhombomeres. In humans, eight rhombomeres can be distinguished, from caudal to rostral: Rh7-Rh1 and the isthmus. Rhombomeres Rh7-Rh4 form the myelencephalon, while Rh3-Rh1 form the metencephalon.

      Understanding neurodevelopment is crucial in comprehending brain development and its complexities. By studying the different areas of the embryonic brain, we can gain insight into the formation of the central nervous system and its functions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 63 - What brain structures are responsible for regulating breathing and heart rate? ...

    Incorrect

    • What brain structures are responsible for regulating breathing and heart rate?

      Your Answer:

      Correct Answer: Medulla

      Explanation:

      The medulla governs the rhythm of the heart and respiration. The amygdala regulates emotional reactions and the ability to perceive the emotions of others. The midbrain is linked to vision, hearing, motor coordination, sleep patterns, alertness, and temperature regulation. The cerebellum manages voluntary movement and balance. The thalamus transmits sensory and motor signals to the cerebral cortex.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 64 - In which region of the brain is Broca's area located? ...

    Incorrect

    • In which region of the brain is Broca's area located?

      Your Answer:

      Correct Answer: Brodmann areas 44 and 45

      Explanation:

      Broca’s and Wernicke’s are two types of expressive dysphasia, which is characterized by difficulty producing speech despite intact comprehension. Dysarthria is a type of expressive dysphasia caused by damage to the speech production apparatus, while Broca’s aphasia is caused by damage to the area of the brain responsible for speech production, specifically Broca’s area located in Brodmann areas 44 and 45. On the other hand, Wernicke’s aphasia is a type of receptive of fluent aphasia caused by damage to the comprehension of speech, while the actual production of speech remains normal. Wernicke’s area is located in the posterior part of the superior temporal gyrus in the dominant hemisphere, within Brodmann area 22.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 65 - In which region of the brain is the ventral tegmental area situated? ...

    Incorrect

    • In which region of the brain is the ventral tegmental area situated?

      Your Answer:

      Correct Answer: Midbrain

      Explanation:

      The Role of the Ventral Tegmental Area in Reward and Pleasure

      The midbrain contains a cluster of dopaminergic cells known as the ventral tegmental area (VTA), which plays a crucial role in the experience of reward and pleasure. These cells are involved in the release of dopamine, a neurotransmitter that is associated with feelings of pleasure and motivation. The VTA is activated in response to various stimuli, such as food, sex, and drugs, and is responsible for the pleasurable sensations that accompany these experiences. Dysfunction in the VTA has been linked to addiction and other disorders related to reward processing. Understanding the role of the VTA in reward and pleasure is essential for developing effective treatments for these conditions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 66 - Patients who attempt suicide often have decreased levels of which substance in their...

    Incorrect

    • Patients who attempt suicide often have decreased levels of which substance in their CSF?

      Your Answer:

      Correct Answer: 5-HIAA

      Explanation:

      Depression, suicidality, and aggression have been linked to decreased levels of 5-HIAA in the CSF.

      The Significance of 5-HIAA in Depression and Aggression

      During the 1980s, there was a brief period of interest in 5-hydroxyindoleacetic acid (5-HIAA), a serotonin metabolite. Studies found that up to a third of people with depression had low concentrations of 5-HIAA in their cerebrospinal fluid (CSF), while very few normal controls did. This suggests that 5-HIAA may play a role in depression.

      Furthermore, individuals with low CSF levels of 5-HIAA have been found to respond less effectively to antidepressants and are more likely to commit suicide. This finding has been replicated in multiple studies, indicating the significance of 5-HIAA in depression.

      Low levels of 5-HIAA are also associated with increased levels of aggression. This suggests that 5-HIAA may play a role in regulating aggressive behavior. Overall, the research on 5-HIAA highlights its potential importance in understanding and treating depression and aggression.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 67 - What is the primary component of Hirano bodies? ...

    Incorrect

    • What is the primary component of Hirano bodies?

      Your Answer:

      Correct Answer: Actin

      Explanation:

      Actin is the primary component of Hirano bodies, which are indicative of neurodegeneration but lack specificity.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 68 - What is located within Brodmann area 22? ...

    Incorrect

    • What is located within Brodmann area 22?

      Your Answer:

      Correct Answer: Wernicke's area

      Explanation:

      Broca’s and Wernicke’s are two types of expressive dysphasia, which is characterized by difficulty producing speech despite intact comprehension. Dysarthria is a type of expressive dysphasia caused by damage to the speech production apparatus, while Broca’s aphasia is caused by damage to the area of the brain responsible for speech production, specifically Broca’s area located in Brodmann areas 44 and 45. On the other hand, Wernicke’s aphasia is a type of receptive of fluent aphasia caused by damage to the comprehension of speech, while the actual production of speech remains normal. Wernicke’s area is located in the posterior part of the superior temporal gyrus in the dominant hemisphere, within Brodmann area 22.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 69 - A researcher studying early childhood development is interested in the formation of the...

    Incorrect

    • A researcher studying early childhood development is interested in the formation of the nervous system. What is the initial step in the development of the nervous system?

      Your Answer:

      Correct Answer: Formation of the neural groove

      Explanation:

      The nervous system in embryos develops from the neural plate, which is a thickening of the ectoderm. The first step in this process is the formation of the neural groove, which is then surrounded by neural folds. These folds gradually come together and fuse to form the neural tube. The neural crest, which is made up of parts of the neural ectoderm, is formed from the rolled-up sides of the neural tube and helps in the development of the peripheral nervous system. The mesencephalon, of midbrain, is formed from the second vesicle of the neural tube. This process of neural development is essential for the proper functioning of the nervous system in later life.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 70 - Which type of nerve fiber lacks a myelin sheath? ...

    Incorrect

    • Which type of nerve fiber lacks a myelin sheath?

      Your Answer:

      Correct Answer: C

      Explanation:

      Primary Afferent Axons: Conveying Information about Touch and Pain

      Primary afferent axons play a crucial role in conveying information about touch and pain from the surface of the body to the spinal cord and brain. These axons can be classified into four types based on their functions: A-alpha (proprioception), A-beta (touch), A-delta (pain and temperature), and C (pain, temperature, and itch). While all A axons are myelinated, C fibers are unmyelinated.

      A-delta fibers are responsible for the sharp initial pain, while C fibers are responsible for the slow, dull, longer-lasting second pain. Understanding the different types of primary afferent axons and their functions is essential in diagnosing and treating various sensory disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 71 - A person who struggles with reproducing intersecting pentagons on the MMSE at an...

    Incorrect

    • A person who struggles with reproducing intersecting pentagons on the MMSE at an older age is likely to experience difficulties with which of the following?

      Your Answer:

      Correct Answer: Non dominant parietal lobe

      Explanation:

      The inability to accurately replicate intersecting pentagons may indicate a constructional apraxia, which is a symptom of non-dominant parietal lobe dysfunction.

      Parietal Lobe Dysfunction: Types and Symptoms

      The parietal lobe is a part of the brain that plays a crucial role in processing sensory information and integrating it with other cognitive functions. Dysfunction in this area can lead to various symptoms, depending on the location and extent of the damage.

      Dominant parietal lobe dysfunction, often caused by a stroke, can result in Gerstmann’s syndrome, which includes finger agnosia, dyscalculia, dysgraphia, and right-left disorientation. Non-dominant parietal lobe dysfunction, on the other hand, can cause anosognosia, dressing apraxia, spatial neglect, and constructional apraxia.

      Bilateral damage to the parieto-occipital lobes, a rare condition, can lead to Balint’s syndrome, which is characterized by oculomotor apraxia, optic ataxia, and simultanagnosia. These symptoms can affect a person’s ability to shift gaze, interact with objects, and perceive multiple objects at once.

      In summary, parietal lobe dysfunction can manifest in various ways, and understanding the specific symptoms can help diagnose and treat the underlying condition.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 72 - What characteristic is unique to neurons and not present in other types of...

    Incorrect

    • What characteristic is unique to neurons and not present in other types of cells?

      Your Answer:

      Correct Answer: Nissl substance

      Explanation:

      Nissl bodies are sizable granules present in neurons that contain rough endoplasmic reticulum and free ribosomes, where protein synthesis occurs. These structures were named after Franz Nissl and exhibit a distinctive purple-blue hue when exposed to Cresyl violet solution, although the reason for this selective staining remains unknown.

      Melanin

      Melanin is a pigment found in various parts of the body, including the skin, hair, and eyes. It is produced by specialized cells called melanocytes, which are located in the skin’s basal layer. The function of melanin in the body is not fully understood, but it is thought to play a role in protecting the skin from the harmful effects of ultraviolet (UV) radiation from the sun. Additionally, melanin may be a by-product of neurotransmitter synthesis, although this function is not well established. Overall, the role of melanin in the body is an area of ongoing research.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 73 - What is the neurotransmitter that encourages sleep? ...

    Incorrect

    • What is the neurotransmitter that encourages sleep?

      Your Answer:

      Correct Answer: Acetylcholine

      Explanation:

      REM sleep is facilitated by the presence of acetylcholine (Ach), while dopamine, histamine, noradrenaline, and serotonin act as inhibitors of sleep.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 74 - What is the definition of sleep latency? ...

    Incorrect

    • What is the definition of sleep latency?

      Your Answer:

      Correct Answer: The time taken to fall asleep after going to bed

      Explanation:

      Sleep Stages

      Sleep is divided into two distinct states called rapid eye movement (REM) and non-rapid eye movement (NREM). NREM is subdivided into four stages.

      Sleep stage
      Approx % of time spent in stage
      EEG findings
      Comment

      I
      5%
      Theta waves (4-7 Hz)
      The dozing off stage. Characterized by hypnic jerks: spontaneous myoclonic contractions associated with a sensation of twitching of falling.

      II
      45%
      Theta waves, K complexes and sleep spindles (short bursts of 12-14 Hz activity)
      Body enters a more subdued state including a drop in temperature, relaxed muscles, and slowed breathing and heart rate. At the same time, brain waves show a new pattern and eye movement stops.

      III
      15%
      Delta waves (0-4 Hz)
      Deepest stage of sleep (high waking threshold). The length of stage 3 decreases over the course of the night.

      IV
      15%
      Mixed, predominantly beta
      High dream activity.

      The percentage of REM sleep decreases with age.

      It takes the average person 15-20 minutes to fall asleep, this is called sleep latency (characterised by the onset of stage I sleep). Once asleep one descends through stages I-II and then III-IV (deep stages). After about 90 minutes of sleep one enters REM. The rest of the sleep comprises of cycles through the stages. As the sleep progresses the periods of REM become greater and the periods of NREM become less. During an average night’s sleep one spends 25% of the sleep in REM and 75% in NREM.

      REM sleep has certain characteristics that separate it from NREM

      Characteristics of REM sleep

      – Autonomic instability (variability in heart rate, respiratory rate, and BP)
      – Loss of muscle tone
      – Dreaming
      – Rapid eye movements
      – Penile erection

      Deafness:

      (No information provided on deafness in relation to sleep stages)

    • This question is part of the following fields:

      • Neurosciences
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  • Question 75 - What brain region has been identified as a target for deep brain stimulation...

    Incorrect

    • What brain region has been identified as a target for deep brain stimulation (DBS) in individuals with treatment-resistant depression?

      Your Answer:

      Correct Answer: Nucleus accumbens

      Explanation:

      Deep brain stimulation (DBS) for treatment resistant depression targets specific brain regions based on their known involvement in pleasure, reward, and mood regulation. The nucleus accumbens is targeted due to its role in pleasure and reward processing. The inferior thalamic peduncle is targeted based on PET studies showing hyperactivity in depression. The lateral habenula is chosen due to observed hypermetabolism in depressed patients. The subgenual cingulate gyrus is targeted due to its hyperactivity in depression. The ventral capsule/ventral striatum is chosen based on its association with improved mood and reduced depressive symptoms following ablation treatments for OCD and depression.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 76 - Which of the following indicates the presence of a dominant parietal lobe injury?...

    Incorrect

    • Which of the following indicates the presence of a dominant parietal lobe injury?

      Your Answer:

      Correct Answer: Finger agnosia

      Explanation:

      Parietal Lobe Dysfunction: Types and Symptoms

      The parietal lobe is a part of the brain that plays a crucial role in processing sensory information and integrating it with other cognitive functions. Dysfunction in this area can lead to various symptoms, depending on the location and extent of the damage.

      Dominant parietal lobe dysfunction, often caused by a stroke, can result in Gerstmann’s syndrome, which includes finger agnosia, dyscalculia, dysgraphia, and right-left disorientation. Non-dominant parietal lobe dysfunction, on the other hand, can cause anosognosia, dressing apraxia, spatial neglect, and constructional apraxia.

      Bilateral damage to the parieto-occipital lobes, a rare condition, can lead to Balint’s syndrome, which is characterized by oculomotor apraxia, optic ataxia, and simultanagnosia. These symptoms can affect a person’s ability to shift gaze, interact with objects, and perceive multiple objects at once.

      In summary, parietal lobe dysfunction can manifest in various ways, and understanding the specific symptoms can help diagnose and treat the underlying condition.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 77 - What is the name of the hormone secreted by the gastrointestinal tract that...

    Incorrect

    • What is the name of the hormone secreted by the gastrointestinal tract that triggers the sensation of hunger?

      Your Answer:

      Correct Answer: Ghrelin

      Explanation:

      Appetite Control Hormones

      The regulation of appetite is influenced by various hormones in the body. Neuropeptide Y, which is produced by the hypothalamus, stimulates appetite. On the other hand, leptin, which is produced by adipose tissue, suppresses appetite. Ghrelin, which is mainly produced by the gut, increases appetite. Cholecystokinin (CCK), which is also produced by the gut, reduces appetite. These hormones play a crucial role in maintaining a healthy balance of food intake and energy expenditure.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 78 - What is believed to be the cause of the negative symptoms observed in...

    Incorrect

    • What is believed to be the cause of the negative symptoms observed in individuals with schizophrenia?

      Your Answer:

      Correct Answer: Decreased dopaminergic activity in the frontal lobe

      Explanation:

      Psychosis is associated with heightened dopaminergic activity in the striatum, while negative symptoms are linked to reduced dopaminergic activity in the frontal lobe.

      The Dopamine Hypothesis is a theory that suggests that dopamine and dopaminergic mechanisms are central to schizophrenia. This hypothesis was developed based on observations that antipsychotic drugs provide at least some degree of D2-type dopamine receptor blockade and that it is possible to induce a psychotic episode in healthy subjects with pharmacological dopamine agonists. The hypothesis was further strengthened by the finding that antipsychotic drugs’ clinical effectiveness was directly related to their affinity for dopamine receptors. Initially, the belief was that the problem related to an excess of dopamine in the brain. However, later studies showed that the relationship between hypofrontality and low cerebrospinal fluid (CSF) dopamine metabolite levels indicates low frontal dopamine levels. Thus, there was a move from a one-sided dopamine hypothesis explaining all facets of schizophrenia to a regionally specific prefrontal hypodopaminergia and a subcortical hyperdopaminergia. In summary, psychosis appears to result from excessive dopamine activity in the striatum, while the negative symptoms seen in schizophrenia appear to result from too little dopamine activity in the frontal lobe. Antipsychotic medications appear to help by countering the effects of increased dopamine by blocking postsynaptic D2 receptors in the striatum.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 79 - What is a true statement about the planum temporale? ...

    Incorrect

    • What is a true statement about the planum temporale?

      Your Answer:

      Correct Answer: It consists of secondary auditory cortex

      Explanation:

      Cerebral Asymmetry in Planum Temporale and its Implications in Language and Auditory Processing

      The planum temporale, a triangular region in the posterior superior temporal gyrus, is a highly lateralized brain structure involved in language and music processing. Studies have shown that the planum temporale is up to ten times larger in the left cerebral hemisphere than the right, with this asymmetry being more prominent in men. This asymmetry can be observed in gestation and is present in up to 70% of right-handed individuals.

      Recent research suggests that the planum temporale also plays an important role in auditory processing, specifically in representing the location of sounds in space. However, reduced planum temporale asymmetry has been observed in individuals with dyslexia, stuttering, and schizophrenia. These findings highlight the importance of cerebral asymmetry in the planum temporale and its implications in language and auditory processing.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 80 - With what condition of disease are Hirano bodies commonly linked? ...

    Incorrect

    • With what condition of disease are Hirano bodies commonly linked?

      Your Answer:

      Correct Answer: Alzheimer's

      Explanation:

      Hirano bodies are considered to be a general indication of neuronal degeneration and are primarily observed in cases of Alzheimer’s disease.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 81 - Anomic aphasia is most likely to occur due to a lesion in which...

    Incorrect

    • Anomic aphasia is most likely to occur due to a lesion in which area?

      Your Answer:

      Correct Answer: Angular gyrus

      Explanation:

      The parahippocampal gyrus is located surrounding the hippocampus and is involved in memory processing. Asymmetry in this area has also been observed in individuals with schizophrenia.

      Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 82 - A child presents with symptoms of dyscalculia, dysgraphia, finger agnosia, and right-left disorientation....

    Incorrect

    • A child presents with symptoms of dyscalculia, dysgraphia, finger agnosia, and right-left disorientation. In which of the following structures would you most expect there to be a lesion?

      Your Answer:

      Correct Answer: Angular gyrus

      Explanation:

      Gerstmann’s Syndrome: Symptoms and Brain Lesions

      Gerstmann’s syndrome is a condition that is characterized by several symptoms, including dyscalculia, dysgraphia, finger agnosia, and right-left disorientation. Patients with this syndrome have been found to have lesions in areas such as the left frontal posterior, left parietal, temporal, and occipital lobes. The left angular gyrus, which is located at the junction of the temporal, occipital, and parietal lobes, seems to be the main area of overlap. Although the function of the angular gyrus is not well understood, it is believed to be involved in various functions such as calculation, spatial reasoning, understanding of ordinal concepts, and comprehension of metaphors.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 83 - In a normal, healthy person during stage III sleep, what EEG patterns would...

    Incorrect

    • In a normal, healthy person during stage III sleep, what EEG patterns would be most expected to be observed?

      Your Answer:

      Correct Answer: Delta waves

      Explanation:

      Sleep Stages

      Sleep is divided into two distinct states called rapid eye movement (REM) and non-rapid eye movement (NREM). NREM is subdivided into four stages.

      Sleep stage
      Approx % of time spent in stage
      EEG findings
      Comment

      I
      5%
      Theta waves (4-7 Hz)
      The dozing off stage. Characterized by hypnic jerks: spontaneous myoclonic contractions associated with a sensation of twitching of falling.

      II
      45%
      Theta waves, K complexes and sleep spindles (short bursts of 12-14 Hz activity)
      Body enters a more subdued state including a drop in temperature, relaxed muscles, and slowed breathing and heart rate. At the same time, brain waves show a new pattern and eye movement stops.

      III
      15%
      Delta waves (0-4 Hz)
      Deepest stage of sleep (high waking threshold). The length of stage 3 decreases over the course of the night.

      IV
      15%
      Mixed, predominantly beta
      High dream activity.

      The percentage of REM sleep decreases with age.

      It takes the average person 15-20 minutes to fall asleep, this is called sleep latency (characterised by the onset of stage I sleep). Once asleep one descends through stages I-II and then III-IV (deep stages). After about 90 minutes of sleep one enters REM. The rest of the sleep comprises of cycles through the stages. As the sleep progresses the periods of REM become greater and the periods of NREM become less. During an average night’s sleep one spends 25% of the sleep in REM and 75% in NREM.

      REM sleep has certain characteristics that separate it from NREM

      Characteristics of REM sleep

      – Autonomic instability (variability in heart rate, respiratory rate, and BP)
      – Loss of muscle tone
      – Dreaming
      – Rapid eye movements
      – Penile erection

      Deafness:

      (No information provided on deafness in relation to sleep stages)

    • This question is part of the following fields:

      • Neurosciences
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      Seconds
  • Question 84 - The dopamine hypothesis of schizophrenia suggests that an overabundance of dopamine in which...

    Incorrect

    • The dopamine hypothesis of schizophrenia suggests that an overabundance of dopamine in which specific pathway is accountable for the heightened importance placed on trivial thoughts and events?

      Your Answer:

      Correct Answer: Mesolimbic pathway

      Explanation:

      The mesolimbic pathway is the correct answer, as it is associated with an excess of dopamine in individuals with addiction. This excess is accompanied by a relative deficiency of dopamine in the frontal lobes. The limbopituitary pathway is not a recognized dopamine pathway, so it should not be considered. The other options listed are all established dopamine pathways.

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 85 - What is the cell type that offers structural support in the central nervous...

    Incorrect

    • What is the cell type that offers structural support in the central nervous system?

      Your Answer:

      Correct Answer: Astrocyte

      Explanation:

      Glial Cells: The Support System of the Central Nervous System

      The central nervous system is composed of two basic cell types: neurons and glial cells. Glial cells, also known as support cells, play a crucial role in maintaining the health and function of neurons. There are several types of glial cells, including macroglia (astrocytes and oligodendrocytes), ependymal cells, and microglia.

      Astrocytes are the most abundant type of glial cell and have numerous functions, such as providing structural support, repairing nervous tissue, nourishing neurons, contributing to the blood-brain barrier, and regulating neurotransmission and blood flow. There are two main types of astrocytes: protoplasmic and fibrous.

      Oligodendrocytes are responsible for the formation of myelin sheaths, which insulate and protect axons, allowing for faster and more efficient transmission of nerve impulses.

      Ependymal cells line the ventricular system and are involved in the circulation of cerebrospinal fluid (CSF) and fluid homeostasis in the brain. Specialized ependymal cells called choroid plexus cells produce CSF.

      Microglia are the immune cells of the CNS and play a crucial role in protecting the brain from infection and injury. They also contribute to the maintenance of neuronal health and function.

      In summary, glial cells are essential for the proper functioning of the central nervous system. They provide structural support, nourishment, insulation, and immune defense to neurons, ensuring the health and well-being of the brain and spinal cord.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 86 - Which of the options below does not belong to the category of small...

    Incorrect

    • Which of the options below does not belong to the category of small molecule neurotransmitters?

      Your Answer:

      Correct Answer: Prolactin

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 87 - What condition is identified by the existence of Pick bodies? ...

    Incorrect

    • What condition is identified by the existence of Pick bodies?

      Your Answer:

      Correct Answer: Frontotemporal dementia

      Explanation:

      Frontotemporal Lobar Degeneration (FTLD) is a pathological term that refers to a group of neurodegenerative disorders that affect the frontal and temporal lobes of the brain. FTLD is classified into several subtypes based on the main protein component of neuronal and glial abnormal inclusions and their distribution. The three main proteins associated with FTLD are Tau, TDP-43, and FUS. Each FTD clinical phenotype has been associated with different proportions of these proteins. Macroscopic changes in FTLD include atrophy of the frontal and temporal lobes, with focal gyral atrophy that resembles knives. Microscopic changes in FTLD-Tau include neuronal and glial tau aggregation, with further sub-classification based on the existence of different isoforms of tau protein. FTLD-TDP is characterized by cytoplasmic inclusions of TDP-43 in neurons, while FTLD-FUS is characterized by cytoplasmic inclusions of FUS.

    • This question is part of the following fields:

      • Neurosciences
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      Seconds
  • Question 88 - What is the name of the neurotransmitter that has an inhibitory effect? ...

    Incorrect

    • What is the name of the neurotransmitter that has an inhibitory effect?

      Your Answer:

      Correct Answer: GABA

      Explanation:

      Excitatory neurotransmitters include glutamate, histamine, acetylcholine, and noradrenaline, as they increase ion flow and the likelihood of action potential in neurons. However, GABA functions as an inhibitory neurotransmitter, reducing ion flow and decreasing the probability of action potential.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 89 - What is the entity responsible for producing myelin in the central nervous system?...

    Incorrect

    • What is the entity responsible for producing myelin in the central nervous system?

      Your Answer:

      Correct Answer: Oligodendrocyte

      Explanation:

      Glial Cells: The Support System of the Central Nervous System

      The central nervous system is composed of two basic cell types: neurons and glial cells. Glial cells, also known as support cells, play a crucial role in maintaining the health and function of neurons. There are several types of glial cells, including macroglia (astrocytes and oligodendrocytes), ependymal cells, and microglia.

      Astrocytes are the most abundant type of glial cell and have numerous functions, such as providing structural support, repairing nervous tissue, nourishing neurons, contributing to the blood-brain barrier, and regulating neurotransmission and blood flow. There are two main types of astrocytes: protoplasmic and fibrous.

      Oligodendrocytes are responsible for the formation of myelin sheaths, which insulate and protect axons, allowing for faster and more efficient transmission of nerve impulses.

      Ependymal cells line the ventricular system and are involved in the circulation of cerebrospinal fluid (CSF) and fluid homeostasis in the brain. Specialized ependymal cells called choroid plexus cells produce CSF.

      Microglia are the immune cells of the CNS and play a crucial role in protecting the brain from infection and injury. They also contribute to the maintenance of neuronal health and function.

      In summary, glial cells are essential for the proper functioning of the central nervous system. They provide structural support, nourishment, insulation, and immune defense to neurons, ensuring the health and well-being of the brain and spinal cord.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 90 - A child is referred to a neurologist. On entering the neurologist's room, the...

    Incorrect

    • A child is referred to a neurologist. On entering the neurologist's room, the child is observed to have a broad-based gait. When introduced, the child's speech is noted to be abnormal. When the child attempts to shake the doctor's hand, a tremor is observed. Which area of the brain is likely to be dysfunctional?

      Your Answer:

      Correct Answer: Cerebellum

      Explanation:

      Cerebellar Dysfunction: Symptoms and Signs

      Cerebellar dysfunction is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. The symptoms and signs of cerebellar dysfunction include ataxia, intention tremor, nystagmus, broad-based gait, slurred speech, dysdiadochokinesis, and dysmetria (lack of finger-nose coordination).

      Ataxia refers to the lack of coordination of voluntary movements, resulting in unsteady gait, difficulty with balance, and clumsiness. Intention tremor is a type of tremor that occurs during voluntary movements, such as reaching for an object. Nystagmus is an involuntary movement of the eyes, characterized by rapid, jerky movements.

      Broad-based gait refers to a wide stance while walking, which is often seen in individuals with cerebellar dysfunction. Slurred speech, also known as dysarthria, is a common symptom of cerebellar dysfunction, which affects the ability to articulate words clearly. Dysdiadochokinesis is the inability to perform rapid alternating movements, such as tapping the fingers on the palm of the hand.

      Dysmetria refers to the inability to accurately judge the distance and direction of movements, resulting in errors in reaching for objects of touching the nose with the finger. These symptoms and signs of cerebellar dysfunction can be caused by a variety of conditions, including stroke, multiple sclerosis, and alcoholism. Treatment depends on the underlying cause and may include medications, physical therapy, and surgery.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 91 - An individual's EEG shows widespread flattening with the existence of theta (θ) and...

    Incorrect

    • An individual's EEG shows widespread flattening with the existence of theta (θ) and delta (δ) waves of low amplitude. What is the most probable diagnosis based on this information?

      Your Answer:

      Correct Answer: Huntington's disease

      Explanation:

      The EEG findings for Huntington’s disease typically show a widespread decrease in activity with low amplitude theta (θ) and delta (δ) waves. In contrast, CJD is characterized by bilateral, synchronous generalised irregular spike wave complexes occurring at a rate of 1-2/second, often accompanied by myoclonic jerks. Hepatic encephalopathy is associated with widespread slowing and triphasic waves, while herpes simplex encephalitis is linked to repetitive episodic discharges and temporal lobe focal slow waves. HIV typically demonstrates diffuse slowing on EEG.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 92 - Which structure is most commonly observed to have pallor in individuals with Lewy...

    Incorrect

    • Which structure is most commonly observed to have pallor in individuals with Lewy body dementia?

      Your Answer:

      Correct Answer: Substantia nigra

      Explanation:

      Lewy body dementia is a neurodegenerative disorder that is characterized by both macroscopic and microscopic changes in the brain. Macroscopically, there is cerebral atrophy, but it is less marked than in Alzheimer’s disease, and the brain weight is usually in the normal range. There is also pallor of the substantia nigra and the locus coeruleus, which are regions of the brain that produce dopamine and norepinephrine, respectively.

      Microscopically, Lewy body dementia is characterized by the presence of intracellular protein accumulations called Lewy bodies. The major component of a Lewy body is alpha synuclein, and as they grow, they start to draw in other proteins such as ubiquitin. Lewy bodies are also found in Alzheimer’s disease, but they tend to be in the amygdala. They can also be found in healthy individuals, although it has been suggested that these may be pre-clinical cases of dementia with Lewy bodies. Lewy bodies are also found in other neurodegenerative disorders such as progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy.

      In Lewy body dementia, Lewy bodies are mainly found within the brainstem, but they are also found in non-brainstem regions such as the amygdaloid nucleus, parahippocampal gyrus, cingulate cortex, and cerebral neocortex. Classic brainstem Lewy bodies are spherical intraneuronal cytoplasmic inclusions, characterized by hyaline eosinophilic cores, concentric lamellar bands, narrow pale halos, and immunoreactivity for alpha synuclein and ubiquitin. In contrast, cortical Lewy bodies typically lack a halo.

      Most brains with Lewy body dementia also show some plaques and tangles, although in most instances, the lesions are not nearly as severe as in Alzheimer’s disease. Neuronal loss and gliosis are usually restricted to brainstem regions, particularly the substantia nigra and locus ceruleus.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 93 - What is a true statement about multisystem atrophy? ...

    Incorrect

    • What is a true statement about multisystem atrophy?

      Your Answer:

      Correct Answer: Associated Parkinson's symptoms respond poorly to levodopa

      Explanation:

      Parkinson plus syndromes, including multisystem atrophy, exhibit a limited efficacy towards Parkinson’s treatment, such as levodopa.

      Multisystem Atrophy: A Parkinson Plus Syndrome

      Multisystem atrophy is a type of Parkinson plus syndrome that is characterized by three main features: Parkinsonism, autonomic failure, and cerebellar ataxia. It can present in three different ways, including Shy-Drager Syndrome, Striatonigral degeneration, and Olivopontocerebellar atrophy, each with varying degrees of the three main features.

      Macroscopic features of multisystem atrophy include pallor of the substantia nigra, greenish discoloration and atrophy of the putamen, and cerebellar atrophy. Microscopic features include the presence of Papp-Lantos bodies, which are alpha-synuclein inclusions found in oligodendrocytes in the substantia nigra, cerebellum, and basal ganglia.

      Overall, multisystem atrophy is a complex and debilitating condition that affects multiple systems in the body, leading to a range of symptoms and challenges for patients and their caregivers.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 94 - What is the most common subtype of Creutzfeldt-Jakob disease (CJD) that is responsible...

    Incorrect

    • What is the most common subtype of Creutzfeldt-Jakob disease (CJD) that is responsible for the majority of cases?

      Your Answer:

      Correct Answer: sCJDMM1 and sCJDMV1

      Explanation:

      CJD has several subtypes, including familial (fCJD), iatrogenic (iCJD), sporadic (sCJD), and new variant (vCJD). The most common subtype is sCJD, which makes up 85% of cases. sCJD can be further classified based on the MV polymorphisms at codon 129 of the PRNP gene, with sCJDMM1 and sCJDMV1 being the most prevalent subtypes. fCJD is the most common subtype after sCJD, while vCJD and iCJD are rare and caused by consuming contaminated food of tissue contamination from other humans, respectively.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 95 - Which area is believed to have the primary role in psychosis due to...

    Incorrect

    • Which area is believed to have the primary role in psychosis due to an overabundance of dopaminergic activity?

      Your Answer:

      Correct Answer: Striatum

      Explanation:

      The Dopamine Hypothesis is a theory that suggests that dopamine and dopaminergic mechanisms are central to schizophrenia. This hypothesis was developed based on observations that antipsychotic drugs provide at least some degree of D2-type dopamine receptor blockade and that it is possible to induce a psychotic episode in healthy subjects with pharmacological dopamine agonists. The hypothesis was further strengthened by the finding that antipsychotic drugs’ clinical effectiveness was directly related to their affinity for dopamine receptors. Initially, the belief was that the problem related to an excess of dopamine in the brain. However, later studies showed that the relationship between hypofrontality and low cerebrospinal fluid (CSF) dopamine metabolite levels indicates low frontal dopamine levels. Thus, there was a move from a one-sided dopamine hypothesis explaining all facets of schizophrenia to a regionally specific prefrontal hypodopaminergia and a subcortical hyperdopaminergia. In summary, psychosis appears to result from excessive dopamine activity in the striatum, while the negative symptoms seen in schizophrenia appear to result from too little dopamine activity in the frontal lobe. Antipsychotic medications appear to help by countering the effects of increased dopamine by blocking postsynaptic D2 receptors in the striatum.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 96 - A 70-year-old patient presents with gait instability, urinary incontinence, and memory impairment. What...

    Incorrect

    • A 70-year-old patient presents with gait instability, urinary incontinence, and memory impairment. What is the most likely diagnosis?

      Your Answer:

      Correct Answer: Normal pressure hydrocephalus

      Explanation:

      Normal Pressure Hydrocephalus

      Normal pressure hydrocephalus is a type of chronic communicating hydrocephalus, which occurs due to the impaired reabsorption of cerebrospinal fluid (CSF) by the arachnoid villi. Although the CSF pressure is typically high, it remains within the normal range, and therefore, it does not cause symptoms of high intracranial pressure (ICP) such as headache and nausea. Instead, patients with normal pressure hydrocephalus usually present with a classic triad of symptoms, including incontinence, gait ataxia, and dementia, which is often referred to as wet, wobbly, and wacky. Unfortunately, this condition is often misdiagnosed as Parkinson’s of Alzheimer’s disease.

      The classic triad of normal pressure hydrocephalus, also known as Hakim’s triad, includes gait instability, urinary incontinence, and dementia. On the other hand, non-communicating hydrocephalus results from the obstruction of CSF flow in the third of fourth ventricle, which causes symptoms of raised intracranial pressure, such as headache, vomiting, hypertension, bradycardia, altered consciousness, and papilledema.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 97 - Which statement accurately describes sporadic CJD? ...

    Incorrect

    • Which statement accurately describes sporadic CJD?

      Your Answer:

      Correct Answer: It tends to affect older rather than younger people

      Explanation:

      Variant CJD primarily affects younger individuals, while sporadic CJD is more commonly seen in older individuals.

      Creutzfeldt-Jakob Disease: Differences between vCJD and CJD

      Creutzfeldt-Jakob Disease (CJD) is a prion disease that includes scrapie, BSE, and Kuru. However, there are important differences between sporadic (also known as classic) CJD and variant CJD. The table below summarizes these differences.

      vCJD:
      – Longer duration from onset of symptoms to death (a year of more)
      – Presents with psychiatric and behavioral symptoms before neurological symptoms
      – MRI shows pulvinar sign
      – EEG shows generalized slowing
      – Originates from infected meat products
      – Affects younger people (age 25-30)

      CJD:
      – Shorter duration from onset of symptoms to death (a few months)
      – Presents with neurological symptoms
      – MRI shows bilateral anterior basal ganglia high signal
      – EEG shows biphasic and triphasic waves 1-2 per second
      – Originates from genetic mutation (bad luck)
      – Affects older people (age 55-65)

      Overall, understanding the differences between vCJD and CJD is important for diagnosis and treatment.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 98 - The nomenclature of PrPSc, the disease-linked form of mammalian prion protein PrP, was...

    Incorrect

    • The nomenclature of PrPSc, the disease-linked form of mammalian prion protein PrP, was derived from a long-observed prion disease in which animal?

      Your Answer:

      Correct Answer: Sheep

      Explanation:

      The term PrPSc originated from scrapie, a prion disease that affects sheep. In humans, the normal isoform of prion protein is PrPC, while the abnormal form is known as PrPres (protease-resistant) of PrPSc. Scrapie has been observed in sheep for over 300 years, while BSE in cattle was only identified in the 1980s. Feline spongiform encephalopathy (FSE) is a prion disease that affects cats, and Chronic wasting disease (CWD) is a similar condition that affects deer.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 99 - From which amino acids are the catecholamines derived? ...

    Incorrect

    • From which amino acids are the catecholamines derived?

      Your Answer:

      Correct Answer: Tyrosine

      Explanation:

      Catecholamines are a group of chemical compounds that have a distinct structure consisting of a benzene ring with two hydroxyl groups, an intermediate ethyl chain, and a terminal amine group. These compounds play an important role in the body and are involved in various physiological processes. The three main catecholamines found in the body are dopamine, adrenaline, and noradrenaline. All of these compounds are derived from the amino acid tyrosine. Overall, catecholamines are essential for maintaining proper bodily functions and are involved in a wide range of physiological processes.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 100 - Which part of a neuron is accountable for generating energy? ...

    Incorrect

    • Which part of a neuron is accountable for generating energy?

      Your Answer:

      Correct Answer: Mitochondria

      Explanation:

      Melanin

      Melanin is a pigment found in various parts of the body, including the skin, hair, and eyes. It is produced by specialized cells called melanocytes, which are located in the skin’s basal layer. The function of melanin in the body is not fully understood, but it is thought to play a role in protecting the skin from the harmful effects of ultraviolet (UV) radiation from the sun. Additionally, melanin may be a by-product of neurotransmitter synthesis, although this function is not well established. Overall, the role of melanin in the body is an area of ongoing research.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 101 - Which statement about dementia pugilistica is accurate? ...

    Incorrect

    • Which statement about dementia pugilistica is accurate?

      Your Answer:

      Correct Answer: Symptoms may result from a single traumatic brain injury

      Explanation:

      Dementia pugilistica, also known as CTE, is categorized as a tauopathy, which is a type of neurodegenerative disease that involves the accumulation of tau protein into NFTs of gliofibrillary tangles in the brain. While it commonly occurs due to repeated brain injuries, it can also develop from a single traumatic event, as reported by Smith in 2013.

      Dementia Pugilistica: A Neurodegenerative Condition Resulting from Neurotrauma

      Dementia pugilistica, also known as chronic traumatic encephalopathy (CTE), is a neurodegenerative condition that results from neurotrauma. It is commonly seen in boxers and NFL players, but can also occur in anyone with neurotrauma. The condition is characterized by symptoms such as gait ataxia, slurred speech, impaired hearing, tremors, disequilibrium, neurobehavioral disturbances, and progressive cognitive decline.

      Most cases of dementia pugilistica present with early onset cognitive deficits, and behavioral signs exhibited by patients include aggression, suspiciousness, paranoia, childishness, hypersexuality, depression, and restlessness. The progression of the condition leads to more prominent behavioral symptoms such as difficulty with impulse control, irritability, inappropriateness, and explosive outbursts of aggression.

      Neuropathological abnormalities have been identified in CTE, with the most unique feature being the abnormal accumulation of tau in neurons and glia in an irregular, focal, perivascular distribution and at the depths of cortical sulci. Abnormalities of the septum pellucidum, such as cavum and fenestration, are also a common feature.

      While the condition has become increasingly rare due to the progressive improvement in sports safety, it is important to recognize the potential long-term consequences of repeated head injuries and take steps to prevent them.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 102 - Which of the following neuroanatomical structures is larger on the left in a...

    Incorrect

    • Which of the following neuroanatomical structures is larger on the left in a healthy right-handed female aged 25-30 years?

      Your Answer:

      Correct Answer: Transverse temporal gyrus

      Explanation:

      The Heschl gyrus, also known as the transverse temporal gyrus, is a component of the primary auditory complex located in the temporal lobe. It is noteworthy that the left Heschl gyrus is typically larger than the right. This structure is responsible for processing incoming auditory information and is unique in its mediolateral orientation. The brain hemispheres exhibit structural differences, with the left hemisphere (in over 90% of right-handed individuals) specializing in language function. Another structure within the primary auditory complex, the planum temporale, is also typically larger on the left side (up to ten times larger). Conversely, the amygdala, caudate nucleus, cingulate sulcus, and hippocampus are typically larger on the right side.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 103 - What cell type plays a significant role in the formation of the blood-brain...

    Incorrect

    • What cell type plays a significant role in the formation of the blood-brain barrier?

      Your Answer:

      Correct Answer: Astrocyte

      Explanation:

      Glial Cells: The Support System of the Central Nervous System

      The central nervous system is composed of two basic cell types: neurons and glial cells. Glial cells, also known as support cells, play a crucial role in maintaining the health and function of neurons. There are several types of glial cells, including macroglia (astrocytes and oligodendrocytes), ependymal cells, and microglia.

      Astrocytes are the most abundant type of glial cell and have numerous functions, such as providing structural support, repairing nervous tissue, nourishing neurons, contributing to the blood-brain barrier, and regulating neurotransmission and blood flow. There are two main types of astrocytes: protoplasmic and fibrous.

      Oligodendrocytes are responsible for the formation of myelin sheaths, which insulate and protect axons, allowing for faster and more efficient transmission of nerve impulses.

      Ependymal cells line the ventricular system and are involved in the circulation of cerebrospinal fluid (CSF) and fluid homeostasis in the brain. Specialized ependymal cells called choroid plexus cells produce CSF.

      Microglia are the immune cells of the CNS and play a crucial role in protecting the brain from infection and injury. They also contribute to the maintenance of neuronal health and function.

      In summary, glial cells are essential for the proper functioning of the central nervous system. They provide structural support, nourishment, insulation, and immune defense to neurons, ensuring the health and well-being of the brain and spinal cord.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 104 - Which substance has the highest level of permeability through the blood brain barrier?...

    Incorrect

    • Which substance has the highest level of permeability through the blood brain barrier?

      Your Answer:

      Correct Answer: Lipid soluble molecules

      Explanation:

      Understanding the Blood Brain Barrier

      The blood brain barrier (BBB) is a crucial component of the brain’s defense system against harmful chemicals and ion imbalances. It is a semi-permeable membrane formed by tight junctions of endothelial cells in the brain’s capillaries, which separates the blood from the cerebrospinal fluid. However, certain areas of the BBB, known as circumventricular organs, are fenestrated to allow neurosecretory products to enter the blood.

      When it comes to MRCPsych questions, the focus is on the following aspects of the BBB: the tight junctions between endothelial cells, the ease with which lipid-soluble molecules pass through compared to water-soluble ones, the difficulty large and highly charged molecules face in passing through, the increased permeability of the BBB during inflammation, and the theoretical ability of nasally administered drugs to bypass the BBB.

      It is important to remember the specific circumventricular organs where the BBB is fenestrated, including the posterior pituitary and the area postrema. Understanding the BBB’s function and characteristics is essential for medical professionals to diagnose and treat neurological disorders effectively.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 105 - Who coined the term 'punch drunk syndrome'? ...

    Incorrect

    • Who coined the term 'punch drunk syndrome'?

      Your Answer:

      Correct Answer: Martland

      Explanation:

      Dementia Pugilistica: A Neurodegenerative Condition Resulting from Neurotrauma

      Dementia pugilistica, also known as chronic traumatic encephalopathy (CTE), is a neurodegenerative condition that results from neurotrauma. It is commonly seen in boxers and NFL players, but can also occur in anyone with neurotrauma. The condition is characterized by symptoms such as gait ataxia, slurred speech, impaired hearing, tremors, disequilibrium, neurobehavioral disturbances, and progressive cognitive decline.

      Most cases of dementia pugilistica present with early onset cognitive deficits, and behavioral signs exhibited by patients include aggression, suspiciousness, paranoia, childishness, hypersexuality, depression, and restlessness. The progression of the condition leads to more prominent behavioral symptoms such as difficulty with impulse control, irritability, inappropriateness, and explosive outbursts of aggression.

      Neuropathological abnormalities have been identified in CTE, with the most unique feature being the abnormal accumulation of tau in neurons and glia in an irregular, focal, perivascular distribution and at the depths of cortical sulci. Abnormalities of the septum pellucidum, such as cavum and fenestration, are also a common feature.

      While the condition has become increasingly rare due to the progressive improvement in sports safety, it is important to recognize the potential long-term consequences of repeated head injuries and take steps to prevent them.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 106 - From which embryonic structure does the thalamus originate? ...

    Incorrect

    • From which embryonic structure does the thalamus originate?

      Your Answer:

      Correct Answer: Diencephalon

      Explanation:

      Neurodevelopment: Understanding Brain Development

      The development of the central nervous system begins with the neuroectoderm, a specialized region of ectoderm. The embryonic brain is divided into three areas: the forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon). The prosencephalon further divides into the telencephalon and diencephalon, while the hindbrain subdivides into the metencephalon and myelencephalon.

      The telencephalon, of cerebrum, consists of the cerebral cortex, underlying white matter, and the basal ganglia. The diencephalon includes the prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum. The mesencephalon comprises the tectum, tegmentum, ventricular mesocoelia, cerebral peduncles, and several nuclei and fasciculi.

      The rhombencephalon includes the medulla, pons, and cerebellum, which can be subdivided into a variable number of transversal swellings called rhombomeres. In humans, eight rhombomeres can be distinguished, from caudal to rostral: Rh7-Rh1 and the isthmus. Rhombomeres Rh7-Rh4 form the myelencephalon, while Rh3-Rh1 form the metencephalon.

      Understanding neurodevelopment is crucial in comprehending brain development and its complexities. By studying the different areas of the embryonic brain, we can gain insight into the formation of the central nervous system and its functions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 107 - Which area of the central nervous system is indicated by a positive outcome...

    Incorrect

    • Which area of the central nervous system is indicated by a positive outcome in the finger-to-nose test?

      Your Answer:

      Correct Answer: Cerebellum

      Explanation:

      The finger-nose test requires the patient to touch their nose and then the examiner’s finger consecutively. If the patient is unable to perform this task, it indicates motor dysmetria, which is a lack of coordination and may indicate a cerebellar injury.

      Cerebellar Dysfunction: Symptoms and Signs

      Cerebellar dysfunction is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. The symptoms and signs of cerebellar dysfunction include ataxia, intention tremor, nystagmus, broad-based gait, slurred speech, dysdiadochokinesis, and dysmetria (lack of finger-nose coordination).

      Ataxia refers to the lack of coordination of voluntary movements, resulting in unsteady gait, difficulty with balance, and clumsiness. Intention tremor is a type of tremor that occurs during voluntary movements, such as reaching for an object. Nystagmus is an involuntary movement of the eyes, characterized by rapid, jerky movements.

      Broad-based gait refers to a wide stance while walking, which is often seen in individuals with cerebellar dysfunction. Slurred speech, also known as dysarthria, is a common symptom of cerebellar dysfunction, which affects the ability to articulate words clearly. Dysdiadochokinesis is the inability to perform rapid alternating movements, such as tapping the fingers on the palm of the hand.

      Dysmetria refers to the inability to accurately judge the distance and direction of movements, resulting in errors in reaching for objects of touching the nose with the finger. These symptoms and signs of cerebellar dysfunction can be caused by a variety of conditions, including stroke, multiple sclerosis, and alcoholism. Treatment depends on the underlying cause and may include medications, physical therapy, and surgery.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 108 - If a certain nerve is damaged, which reflex may not occur during the...

    Incorrect

    • If a certain nerve is damaged, which reflex may not occur during the jaw jerk test?

      Your Answer:

      Correct Answer: Trigeminal

      Explanation:

      Cranial Nerve Reflexes

      When it comes to questions on cranial nerve reflexes, it is important to match the reflex to the nerves involved. Here are some examples:

      – Pupillary light reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Accommodation reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Jaw jerk: involves the trigeminal nerve (sensory and motor).
      – Corneal reflex: involves the trigeminal nerve (sensory) and facial nerve (motor).
      – Vestibulo-ocular reflex: involves the vestibulocochlear nerve (sensory) and oculomotor, trochlear, and abducent nerves (motor).

      Another example of a cranial nerve reflex is the gag reflex, which involves the glossopharyngeal nerve (sensory) and the vagus nerve (motor). This reflex is important for protecting the airway from foreign objects of substances that may trigger a gag reflex. It is also used as a diagnostic tool to assess the function of these nerves.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 109 - What statement accurately describes ionotropic receptors? ...

    Incorrect

    • What statement accurately describes ionotropic receptors?

      Your Answer:

      Correct Answer: GABA-A is an example of an ionotropic receptor

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 110 - Which cranial nerve reflex is most likely to be impacted by a vagus...

    Incorrect

    • Which cranial nerve reflex is most likely to be impacted by a vagus nerve lesion?

      Your Answer:

      Correct Answer: Gag

      Explanation:

      Cranial Nerve Reflexes

      When it comes to questions on cranial nerve reflexes, it is important to match the reflex to the nerves involved. Here are some examples:

      – Pupillary light reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Accommodation reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Jaw jerk: involves the trigeminal nerve (sensory and motor).
      – Corneal reflex: involves the trigeminal nerve (sensory) and facial nerve (motor).
      – Vestibulo-ocular reflex: involves the vestibulocochlear nerve (sensory) and oculomotor, trochlear, and abducent nerves (motor).

      Another example of a cranial nerve reflex is the gag reflex, which involves the glossopharyngeal nerve (sensory) and the vagus nerve (motor). This reflex is important for protecting the airway from foreign objects of substances that may trigger a gag reflex. It is also used as a diagnostic tool to assess the function of these nerves.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 111 - Which cranial nerve travels through the cribriform plate of the ethmoid bone on...

    Incorrect

    • Which cranial nerve travels through the cribriform plate of the ethmoid bone on its way to the brain?

      Your Answer:

      Correct Answer: Olfactory nerve

      Explanation:

      The olfactory nerves are responsible for the sense of smell. They originate in the upper part of the nose’s mucous membrane and travel through the ethmoid bone’s cribriform plate. From there, they reach the olfactory bulb, where nerve cells synapse and transmit the impulse to a second neuron. Finally, the nerves travel to the temporal lobe of the cerebrum, where the perception of smell occurs.

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 112 - Which of the following ocular presentations is atypical for multiple sclerosis? ...

    Incorrect

    • Which of the following ocular presentations is atypical for multiple sclerosis?

      Your Answer:

      Correct Answer: Raised intraocular pressure

      Explanation:

      There is no correlation between multiple sclerosis and raised intraocular pressure, which is known as glaucoma when accompanied by visual field loss.

      Multiple Sclerosis: An Overview

      Multiple sclerosis is a neurological disorder that is classified into three categories: primary progressive, relapsing-remitting, and secondary progressive. Primary progressive multiple sclerosis affects 5-10% of patients and is characterized by a steady progression with no remissions. Relapsing-remitting multiple sclerosis affects 20-30% of patients and presents with a relapsing-remitting course but does not lead to serious disability. Secondary progressive multiple sclerosis affects 60% of patients and initially presents with a relapsing-remitting course but is then followed by a phase of progressive deterioration.

      The disorder typically begins between the ages of 20 and 40 and is characterized by multiple demyelinating lesions that have a preference for the optic nerves, cerebellum, brainstem, and spinal cord. Patients with multiple sclerosis present with a variety of neurological signs that reflect the presence and distribution of plaques. Ocular features of multiple sclerosis include optic neuritis, internuclear ophthalmoplegia, and ocular motor cranial neuropathy.

      Multiple sclerosis is more common in women than in men and is seen with increasing frequency as the distance from the equator increases. It is believed to be caused by a combination of genetic and environmental factors, with monozygotic concordance at 25%. Overall, multiple sclerosis is a predominantly white matter disease that can have a significant impact on a patient’s quality of life.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 113 - What hormone is produced by the posterior pituitary gland? ...

    Incorrect

    • What hormone is produced by the posterior pituitary gland?

      Your Answer:

      Correct Answer: Antidiuretic hormone (ADH)

      Explanation:

      The posterior pituitary secretes antidiuretic hormone (ADH) and oxytocin, while the anterior pituitary secretes human growth hormone (HGH), adrenocorticotropic hormone (ACTH), prolactin (PRL), thyroid-stimulating hormone (TSH), luteinising hormone (LH), and follicle-stimulating hormone (FSH).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 114 - If a patient suspected of having a stroke presents with a deviation of...

    Incorrect

    • If a patient suspected of having a stroke presents with a deviation of the tongue towards the right, which nerve is likely to be impacted?

      Your Answer:

      Correct Answer: Right hypoglossal nerve

      Explanation:

      The hypoglossal nerve (nerve XII) is responsible for controlling the motor functions of the tongue and the muscles surrounding the hyoid bone. As a result, when there is a lesion on the right side, the tongue will tend to deviate towards that side. It is important to note that the hypoglossal nerve is purely a motor nerve and does not have any sensory component.

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 115 - An EEG analysis indicates the presence of a mass in the brain. What...

    Incorrect

    • An EEG analysis indicates the presence of a mass in the brain. What were the observed wave patterns?

      Your Answer:

      Correct Answer: Delta activity (δ)

      Explanation:

      While alpha (α) and beta (β) activity are typical in adults who are awake and at rest, delta activity (δ) may suggest the presence of a brain tumor. Mu (μ) activity is linked to movement, and theta activity (θ) is uncommon in the waking adult population, occurring briefly in only 15% of individuals.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 116 - What is the inability of a patient with astereognosia? ...

    Incorrect

    • What is the inability of a patient with astereognosia?

      Your Answer:

      Correct Answer: Recognise objects by touch

      Explanation:

      Agnosia is a condition where a person loses the ability to recognize objects, persons, sounds, shapes, of smells, despite having no significant memory loss of defective senses. There are different types of agnosia, such as prosopagnosia (inability to recognize familiar faces), anosognosia (inability to recognize one’s own condition/illness), autotopagnosia (inability to orient parts of the body), phonagnosia (inability to recognize familiar voices), simultanagnosia (inability to appreciate two objects in the visual field at the same time), and astereoagnosia (inability to recognize objects by touch).

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      • Neurosciences
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  • Question 117 - Which condition is most likely to exhibit a hyperkinetic gait? ...

    Incorrect

    • Which condition is most likely to exhibit a hyperkinetic gait?

      Your Answer:

      Correct Answer: Sydenham chorea

      Explanation:

      Gait disorders can be caused by a variety of conditions, including neurological, muscular, and structural abnormalities. One common gait disorder is hemiplegic gait, which is characterized by unilateral weakness on the affected side, with the arm flexed, adducted, and internally rotated, and the leg on the same side in extension with plantar flexion of the foot and toes. When walking, the patient may hold their arm to one side and drag their affected leg in a semicircle (circumduction) due to weakness of leg flexors and extended foot. Hemiplegic gait is often seen in patients who have suffered a stroke.

      Other gait disorders include ataxic gait, spastic gait, and steppage gait, each with their own unique characteristics and associated conditions. Accurate diagnosis and treatment of gait disorders is important for improving mobility and quality of life for affected individuals.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 118 - Which of the following is believed to be caused by the obstruction of...

    Incorrect

    • Which of the following is believed to be caused by the obstruction of D-2 receptors in the mesolimbic pathway?

      Your Answer:

      Correct Answer: The therapeutic effects of antipsychotics in schizophrenia

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 119 - What neuroimaging result is typically seen in individuals diagnosed with obsessive compulsive disorder?...

    Incorrect

    • What neuroimaging result is typically seen in individuals diagnosed with obsessive compulsive disorder?

      Your Answer:

      Correct Answer: Hypermetabolism of orbitofrontal area

      Explanation:

      This question is a common one, but it is worded in various ways each time.

      Neuroimaging Findings in Obsessive-Compulsive Disorder (OCD)

      Obsessive-compulsive disorder (OCD) is a mental disorder characterized by intrusive thoughts (obsessions) and repetitive behaviors (compulsions). Neuroimaging studies have been conducted to investigate the underlying neural mechanisms of OCD. Two commonly used techniques are 18 Fluorodeoxyglucose PET (FDG-PET) and Technetium-99m (99mTc)-hexamethylpropyleneamine-oxime SPECT (HMPAO-SPECT).

      Studies using FDG-PET have reported increased glucose metabolism in several brain regions among OCD patients, including the orbitofrontal cortex (OFC), caudate, thalamus, prefrontal cortex, and anterior cingulate. These regions are involved in cognitive and emotional processing, decision-making, and motor control. The increased activity in these regions may contribute to the symptoms of OCD, such as repetitive behaviors and difficulty controlling intrusive thoughts.

      On the other hand, studies using HMPAO-SPECT have found both increased and decreased blood flow to various brain regions in OCD patients compared to normal controls. These regions include the OFC, caudate, various areas of the cortex, and thalamus. The inconsistent findings may be due to differences in the severity and subtype of OCD, as well as the specific task of stimulus used in the imaging studies.

      Overall, neuroimaging studies have provided valuable insights into the neural mechanisms of OCD. However, further research is needed to better understand the complex interactions between different brain regions and how they contribute to the development and maintenance of OCD symptoms.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 120 - Through which opening in the skull does the cranial nerve exit that is...

    Incorrect

    • Through which opening in the skull does the cranial nerve exit that is known as the superior orbital fissure?

      Your Answer:

      Correct Answer: Abducens (VI)

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 121 - What is the main producer of serotonin in the brain? ...

    Incorrect

    • What is the main producer of serotonin in the brain?

      Your Answer:

      Correct Answer: Raphe nuclei

      Explanation:

      The pituitary gland is situated in the sella turcica, while the suprachiasmatic nucleus regulates circadian rhythms. Serotonin release in the brain is primarily sourced from the neurons of the raphe nuclei, which are located along the midline of the brainstem. The choroid plexus produces cerebrospinal fluid, and enterochromaffin cells in the gut contain the majority of the body’s serotonin.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 122 - What is the most probable outcome of a blockage in the anterior cerebral...

    Incorrect

    • What is the most probable outcome of a blockage in the anterior cerebral artery?

      Your Answer:

      Correct Answer: Motor aphasia

      Explanation:

      The frontal part of the brain responsible for motor function is supplied by the anterior cerebral artery.

      Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 123 - Are athetoid movements commonly associated with basal ganglia dysfunction rather than cerebellar dysfunction?...

    Incorrect

    • Are athetoid movements commonly associated with basal ganglia dysfunction rather than cerebellar dysfunction?

      Your Answer:

      Correct Answer: Athetoid movements

      Explanation:

      Abnormal movements known as athetoid movements are commonly associated with issues in the basal ganglia.

      Cerebellar Dysfunction: Symptoms and Signs

      Cerebellar dysfunction is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. The symptoms and signs of cerebellar dysfunction include ataxia, intention tremor, nystagmus, broad-based gait, slurred speech, dysdiadochokinesis, and dysmetria (lack of finger-nose coordination).

      Ataxia refers to the lack of coordination of voluntary movements, resulting in unsteady gait, difficulty with balance, and clumsiness. Intention tremor is a type of tremor that occurs during voluntary movements, such as reaching for an object. Nystagmus is an involuntary movement of the eyes, characterized by rapid, jerky movements.

      Broad-based gait refers to a wide stance while walking, which is often seen in individuals with cerebellar dysfunction. Slurred speech, also known as dysarthria, is a common symptom of cerebellar dysfunction, which affects the ability to articulate words clearly. Dysdiadochokinesis is the inability to perform rapid alternating movements, such as tapping the fingers on the palm of the hand.

      Dysmetria refers to the inability to accurately judge the distance and direction of movements, resulting in errors in reaching for objects of touching the nose with the finger. These symptoms and signs of cerebellar dysfunction can be caused by a variety of conditions, including stroke, multiple sclerosis, and alcoholism. Treatment depends on the underlying cause and may include medications, physical therapy, and surgery.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 124 - Which type of injury of damage typically leads to utilization behaviour? ...

    Incorrect

    • Which type of injury of damage typically leads to utilization behaviour?

      Your Answer:

      Correct Answer: Frontal lobe

      Explanation:

      Abnormal Motor Behaviours Associated with Utilization Behaviour

      Utilization behaviour (UB) is a condition where patients exhibit exaggerated and inappropriate motor responses to environmental cues and objects. This behaviour is automatic and instrumentally correct, but not contextually appropriate. For instance, a patient may start brushing their teeth when presented with a toothbrush, even in a setting where it is not expected. UB is caused by frontal lobe lesions that result in a loss of inhibitory control.

      Other motor abnormalities associated with UB include imitation behaviour, where patients tend to imitate the examiner’s behaviour, and the alien hand sign, where patients experience bizarre hand movements that they cannot control. Manual groping behaviour is also observed, where patients automatically manipulate objects placed in front of them. The grasp reflex, which is normal in infants, should not be present in children and adults. It is an automatic tendency to grip objects of stimuli, such as the examiner’s hand.

      Environmental Dependency Syndrome is another condition associated with UB. It describes deficits in personal control of action and an overreliance on social and physical environmental stimuli to guide behaviour in a social context. For example, a patient may start commenting on pictures in an examiner’s office, believing it to be an art gallery.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 125 - The prevention of abnormal amyloid protein formation in senile plaques is achieved through...

    Incorrect

    • The prevention of abnormal amyloid protein formation in senile plaques is achieved through the cleavage of amyloid precursor protein by which of the following?

      Your Answer:

      Correct Answer: Alpha secretase

      Explanation:

      Amyloid Precursor Protein and its Role in Alzheimer’s Disease

      Amyloid precursor protein (APP) is a crucial component of amyloid plaques, which are a hallmark of Alzheimer’s disease. When APP is cleaved by beta-secretase, it produces beta-amyloid (Abeta), the primary component of senile plaques in Alzheimer’s disease. On the other hand, cleavage of APP by alpha-secretase prevents Abeta formation, leading to the production of non amyloidogenic secreted APPs products.

      The accumulation of Abeta in the brain is believed to be a key factor in the development and progression of Alzheimer’s disease. Abeta peptides aggregate to form amyloid plaques, which can disrupt neuronal function and lead to cognitive decline. Therefore, understanding the mechanisms that regulate APP processing and Abeta production is crucial for developing effective treatments for Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 126 - Which lobe of the brain is responsible for causing Gerstmann's syndrome when it...

    Incorrect

    • Which lobe of the brain is responsible for causing Gerstmann's syndrome when it malfunctions?

      Your Answer:

      Correct Answer: Dominant parietal

      Explanation:

      Parietal Lobe Dysfunction: Types and Symptoms

      The parietal lobe is a part of the brain that plays a crucial role in processing sensory information and integrating it with other cognitive functions. Dysfunction in this area can lead to various symptoms, depending on the location and extent of the damage.

      Dominant parietal lobe dysfunction, often caused by a stroke, can result in Gerstmann’s syndrome, which includes finger agnosia, dyscalculia, dysgraphia, and right-left disorientation. Non-dominant parietal lobe dysfunction, on the other hand, can cause anosognosia, dressing apraxia, spatial neglect, and constructional apraxia.

      Bilateral damage to the parieto-occipital lobes, a rare condition, can lead to Balint’s syndrome, which is characterized by oculomotor apraxia, optic ataxia, and simultanagnosia. These symptoms can affect a person’s ability to shift gaze, interact with objects, and perceive multiple objects at once.

      In summary, parietal lobe dysfunction can manifest in various ways, and understanding the specific symptoms can help diagnose and treat the underlying condition.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 127 - What is the entity that carries out phagocytosis in the central nervous system?...

    Incorrect

    • What is the entity that carries out phagocytosis in the central nervous system?

      Your Answer:

      Correct Answer: Microglia

      Explanation:

      Glial Cells: The Support System of the Central Nervous System

      The central nervous system is composed of two basic cell types: neurons and glial cells. Glial cells, also known as support cells, play a crucial role in maintaining the health and function of neurons. There are several types of glial cells, including macroglia (astrocytes and oligodendrocytes), ependymal cells, and microglia.

      Astrocytes are the most abundant type of glial cell and have numerous functions, such as providing structural support, repairing nervous tissue, nourishing neurons, contributing to the blood-brain barrier, and regulating neurotransmission and blood flow. There are two main types of astrocytes: protoplasmic and fibrous.

      Oligodendrocytes are responsible for the formation of myelin sheaths, which insulate and protect axons, allowing for faster and more efficient transmission of nerve impulses.

      Ependymal cells line the ventricular system and are involved in the circulation of cerebrospinal fluid (CSF) and fluid homeostasis in the brain. Specialized ependymal cells called choroid plexus cells produce CSF.

      Microglia are the immune cells of the CNS and play a crucial role in protecting the brain from infection and injury. They also contribute to the maintenance of neuronal health and function.

      In summary, glial cells are essential for the proper functioning of the central nervous system. They provide structural support, nourishment, insulation, and immune defense to neurons, ensuring the health and well-being of the brain and spinal cord.

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      • Neurosciences
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  • Question 128 - You are evaluating a 72-year-old man in your office who had a stroke...

    Incorrect

    • You are evaluating a 72-year-old man in your office who had a stroke four weeks ago. His wife reports that he is having difficulty recognizing familiar faces, but is otherwise functioning normally. What is the most appropriate term for his condition?

      Your Answer:

      Correct Answer: Prosopagnosia

      Explanation:

      Prosopagnosia is a condition where individuals are unable to recognize familiar faces, which can be caused by damage to the fusiform area of be congenital. Achromatopsia, on the other hand, is color blindness that can result from thalamus damage. Parietal lobe lesions can cause agraphesthesia, which is the inability to recognize numbers of letters traced on the palm, and astereognosis, which is the inability to recognize an item by touch. Lastly, phonagnosia is the inability to recognize familiar voices and is the auditory equivalent of prosopagnosia, although it is not as well-researched.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 129 - What is a true statement about senile plaques? ...

    Incorrect

    • What is a true statement about senile plaques?

      Your Answer:

      Correct Answer: They consist of beta amyloid

      Explanation:

      Senile plaques are formed by beta amyloid proteins that have folded abnormally and are found in the extracellular space of the grey matter. While they are present in smaller quantities during normal aging, they are insoluble. These plaques are created due to the improper cleavage of Amyloid Precursor Protein (APP), a transmembrane protein whose function is not fully understood.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 130 - Age-related plaques are made up of what substances? ...

    Incorrect

    • Age-related plaques are made up of what substances?

      Your Answer:

      Correct Answer: Beta amyloid

      Explanation:

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 131 - Which interleukin has been consistently found to be present in higher levels in...

    Incorrect

    • Which interleukin has been consistently found to be present in higher levels in individuals with depression compared to those without depression?

      Your Answer:

      Correct Answer: IL-6

      Explanation:

      Inflammatory Cytokines and Mental Health

      Research has suggested that an imbalance in the immune system, particularly the pro-inflammatory cytokines, may play a significant role in the development of common mental disorders. The strongest evidence is found in depression, where studies have shown increased levels of inflammatory markers, such as interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and c-reactive protein (CRP), in depressed individuals compared to healthy controls (Santoft, 2020).

      While most studies have focused on the differences in inflammatory markers between depressed and healthy individuals, some have also found a correlation between higher levels of inflammation and more severe depressive symptoms. The underlying cause of this chronic low-grade inflammation is not yet fully understood, but potential factors include psychosocial stress, physical inactivity, poor diet, smoking, obesity, altered gut permeability, disturbed sleep, and vitamin D deficiency.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 132 - What is the role of the Golgi apparatus in a neuron? ...

    Incorrect

    • What is the role of the Golgi apparatus in a neuron?

      Your Answer:

      Correct Answer: Packaging of macromolecules

      Explanation:

      Melanin

      Melanin is a pigment found in various parts of the body, including the skin, hair, and eyes. It is produced by specialized cells called melanocytes, which are located in the skin’s basal layer. The function of melanin in the body is not fully understood, but it is thought to play a role in protecting the skin from the harmful effects of ultraviolet (UV) radiation from the sun. Additionally, melanin may be a by-product of neurotransmitter synthesis, although this function is not well established. Overall, the role of melanin in the body is an area of ongoing research.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 133 - What is the hypothalamic nucleus that is responsible for regulating heat generation and...

    Incorrect

    • What is the hypothalamic nucleus that is responsible for regulating heat generation and conservation?

      Your Answer:

      Correct Answer: Posterior

      Explanation:

      Functions of the Hypothalamus

      The hypothalamus is a vital part of the brain that plays a crucial role in regulating various bodily functions. It receives and integrates sensory information about the internal environment and directs actions to control internal homeostasis. The hypothalamus contains several nuclei and fiber tracts, each with specific functions.

      The suprachiasmatic nucleus (SCN) is responsible for regulating circadian rhythms. Neurons in the SCN have an intrinsic rhythm of discharge activity and receive input from the retina. The SCN is considered the body’s master clock, but it has multiple connections with other hypothalamic nuclei.

      Body temperature control is mainly under the control of the preoptic, anterior, and posterior nuclei, which have temperature-sensitive neurons. As the temperature goes above 37ºC, warm-sensitive neurons are activated, triggering parasympathetic activity to promote heat loss. As the temperature goes below 37ºC, cold-sensitive neurons are activated, triggering sympathetic activity to promote conservation of heat.

      The hypothalamus also plays a role in regulating prolactin secretion. Dopamine is tonically secreted by dopaminergic neurons that project from the arcuate nucleus of the hypothalamus into the anterior pituitary gland via the tuberoinfundibular pathway. The dopamine that is released acts on lactotrophic cells through D2-receptors, inhibiting prolactin synthesis. In the absence of pregnancy of lactation, prolactin is constitutively inhibited by dopamine. Dopamine antagonists result in hyperprolactinemia, while dopamine agonists inhibit prolactin secretion.

      In summary, the hypothalamus is a complex structure that regulates various bodily functions, including circadian rhythms, body temperature, and prolactin secretion. Dysfunction of the hypothalamus can lead to various disorders, such as sleep-rhythm disorder, diabetes insipidus, hyperprolactinemia, and obesity.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 134 - In what type of epilepsy is it most common to experience an aura?...

    Incorrect

    • In what type of epilepsy is it most common to experience an aura?

      Your Answer:

      Correct Answer: Complex partial

      Explanation:

      This question is presented in two variations on the exam, with one implying that auras are primarily linked to temporal lobe epilepsy and the other to complex partial seizures. In reality, partial seizures are most commonly associated with auras compared to other types of seizures. While partial seizures can originate in any lobe of the brain, those that arise in the temporal lobe are most likely to produce an aura. Therefore, both versions of the question are accurate.

      Epilepsy and Aura

      An aura is a subjective sensation that is a type of simple partial seizure. It typically lasts only a few seconds and can help identify the site of cortical onset. There are eight recognized types of auras, including somatosensory, visual, auditory, gustatory, olfactory, autonomic, abdominal, and psychic.

      In about 80% of cases, auras precede temporal lobe seizures. The most common auras in these seizures are abdominal and psychic, which can cause a rising epigastric sensation of feelings of fear, déjà vu, of jamais vu. Parietal lobe seizures may begin with a contralateral sensation, usually of the positive type, such as an electrical sensation of tingling. Occipital lobe seizures may begin with contralateral visual changes, such as colored lines, spots, of shapes, of even a loss of vision. Temporal-parietal-occipital seizures may produce more formed auras.

      Complex partial seizures are defined by impairment of consciousness, which means decreased responsiveness and awareness of oneself and surroundings. During a complex partial seizure, a patient is unresponsive and does not remember events that occurred.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 135 - From which gland is melatonin secreted? ...

    Incorrect

    • From which gland is melatonin secreted?

      Your Answer:

      Correct Answer: Pineal

      Explanation:

      The pineal gland secretes melatonin, while the adrenal glands secrete cortisol, aldosterone, adrenaline, and noradrenaline. The release of pituitary hormones is regulated by the hypothalamus, which synthesizes and secretes releasing hormones. Additionally, the parathyroid glands secrete parathyroid hormone (PTH).

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      • Neurosciences
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  • Question 136 - A 40-year-old individual who has been struggling with opioid addiction is experiencing symptoms...

    Incorrect

    • A 40-year-old individual who has been struggling with opioid addiction is experiencing symptoms of opioid dependence. What electroencephalographic alterations are commonly observed in cases of opioid dependence?

      Your Answer:

      Correct Answer: Decreased alpha activity

      Explanation:

      Opioid dependence is characterized by a decrease in alpha activity on electroencephalography (EEG). Other drugs have distinct EEG changes, such as increased beta activity with benzodiazepines, decreased alpha activity and increased theta activity with alcohol, and increased beta activity with barbiturates. Marijuana use is associated with increased alpha activity in the frontal area of the brain and overall slow alpha activity. During opioid overdose, slow waves may be observed on EEG, while barbiturate withdrawal may result in generalized paroxysmal activity and spike discharges.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 137 - Which component is excluded from the Papez circuit? ...

    Incorrect

    • Which component is excluded from the Papez circuit?

      Your Answer:

      Correct Answer: Caudate nucleus

      Explanation:

      The basal ganglia includes the caudate nucleus.

      The Papez Circuit: A Neural Pathway for Emotion

      James Papez was the first to describe a neural pathway in the brain that mediates the process of emotion. This pathway is known as the ‘Papez circuit’ and is located on the medial surface of the brain. It is bilateral, symmetrical, and links the cortex to the hypothalamus.

      According to Papez, information about emotion passes through several structures in the brain, including the hippocampus, the Mammillary bodies of the hypothalamus, the anterior nucleus of the thalamus, the cingular cortex, and the entorhinal cortex. Finally, the information passes through the hippocampus again, completing the circuit.

      The Papez circuit was one of the first descriptions of the limbic system, which is responsible for regulating emotions, motivation, and memory. Understanding the Papez circuit and the limbic system has important implications for understanding and treating emotional disorders such as anxiety and depression.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 138 - What substance precedes the production of serotonin? ...

    Incorrect

    • What substance precedes the production of serotonin?

      Your Answer:

      Correct Answer: 5-hydroxytryptophan

      Explanation:

      Serotonin: Synthesis and Breakdown

      Serotonin, also known as 5-Hydroxytryptamine (5-HT), is synthesized in the central nervous system (CNS) in the raphe nuclei located in the brainstem, as well as in the gastrointestinal (GI) tract in enterochromaffin cells. The amino acid L-tryptophan, obtained from the diet, is used to synthesize serotonin. L-tryptophan can cross the blood-brain barrier, but serotonin cannot.

      The transformation of L-tryptophan into serotonin involves two steps. First, hydroxylation to 5-hydroxytryptophan is catalyzed by tryptophan hydroxylase. Second, decarboxylation of 5-hydroxytryptophan to serotonin (5-hydroxytryptamine) is catalyzed by L-aromatic amino acid decarboxylase.

      Serotonin is taken up from the synapse by a monoamine transporter (SERT). Substances that block this transporter include MDMA, amphetamine, cocaine, TCAs, and SSRIs. Serotonin is broken down by monoamine oxidase (MAO) and then by aldehyde dehydrogenase to 5-Hydroxyindoleacetic acid (5-HIAA).

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      • Neurosciences
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  • Question 139 - A 45-year-old man presents with contralateral hemisensory loss and reports experiencing intense burning...

    Incorrect

    • A 45-year-old man presents with contralateral hemisensory loss and reports experiencing intense burning pain in the affected region. What is the probable location of arterial blockage?

      Your Answer:

      Correct Answer: Thalamogeniculate artery

      Explanation:

      When a stroke affects the thalamus, it can cause loss of sensation on the opposite side of the body and intense burning pain that can be treated with tricyclics. This type of sensory loss is commonly seen in conditions that affect the brain stem, thalamus, of cortex. In addition, a stroke in the thalamogeniculate artery can result in temporary paralysis on the opposite side of the body, followed by ataxia, and involuntary movements. Facial expression may also be affected. Treatment for these patients is similar to that for other stroke patients.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 140 - Which of the following is a catecholamine? ...

    Incorrect

    • Which of the following is a catecholamine?

      Your Answer:

      Correct Answer: Adrenaline

      Explanation:

      Catecholamines are a group of chemical compounds that have a distinct structure consisting of a benzene ring with two hydroxyl groups, an intermediate ethyl chain, and a terminal amine group. These compounds play an important role in the body and are involved in various physiological processes. The three main catecholamines found in the body are dopamine, adrenaline, and noradrenaline. All of these compounds are derived from the amino acid tyrosine. Overall, catecholamines are essential for maintaining proper bodily functions and are involved in a wide range of physiological processes.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 141 - Through which structure does the mandibular division of the trigeminal nerve exit the...

    Incorrect

    • Through which structure does the mandibular division of the trigeminal nerve exit the cranial cavity?

      Your Answer:

      Correct Answer: Foramen ovale

      Explanation:

      Cranial Fossae and Foramina

      The cranium is divided into three regions known as fossae, each housing different cranial lobes. The anterior cranial fossa contains the frontal lobes and includes the frontal and ethmoid bones, as well as the lesser wing of the sphenoid. The middle cranial fossa contains the temporal lobes and includes the greater wing of the sphenoid, sella turcica, and most of the temporal bones. The posterior cranial fossa contains the occipital lobes, cerebellum, and medulla and includes the occipital bone.

      There are several foramina in the skull that allow for the passage of various structures. The most important foramina likely to appear in exams are listed below:

      – Foramen spinosum: located in the middle fossa and allows for the passage of the middle meningeal artery.
      – Foramen ovale: located in the middle fossa and allows for the passage of the mandibular division of the trigeminal nerve.
      – Foramen lacerum: located in the middle fossa and allows for the passage of the small meningeal branches of the ascending pharyngeal artery and emissary veins from the cavernous sinus.
      – Foramen magnum: located in the posterior fossa and allows for the passage of the spinal cord.
      – Jugular foramen: located in the posterior fossa and allows for the passage of cranial nerves IX, X, and XI.

      Understanding the location and function of these foramina is essential for medical professionals, as they play a crucial role in the diagnosis and treatment of various neurological conditions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 142 - What is the outcome of bilateral dysfunction in the medial temporal lobes? ...

    Incorrect

    • What is the outcome of bilateral dysfunction in the medial temporal lobes?

      Your Answer:

      Correct Answer: Klüver-Bucy syndrome

      Explanation:

      Periods of hypersomnia and altered behavior are characteristic of Kleine-Levin syndrome.

      Kluver-Bucy Syndrome: Causes and Symptoms

      Kluver-Bucy syndrome is a neurological disorder that results from bilateral medial temporal lobe dysfunction, particularly in the amygdala. This condition is characterized by a range of symptoms, including hyperorality (a tendency to explore objects with the mouth), hypersexuality, docility, visual agnosia, and dietary changes.

      The most common causes of Kluver-Bucy syndrome include herpes, late-stage Alzheimer’s disease, frontotemporal dementia, trauma, and bilateral temporal lobe infarction. In some cases, the condition may be reversible with treatment, but in others, it may be permanent and require ongoing management. If you of someone you know is experiencing symptoms of Kluver-Bucy syndrome, it is important to seek medical attention promptly to determine the underlying cause and develop an appropriate treatment plan.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 143 - Which prion disease exhibits minimal of no spongiform alteration? ...

    Incorrect

    • Which prion disease exhibits minimal of no spongiform alteration?

      Your Answer:

      Correct Answer: Fatal familial insomnia (FFI)

      Explanation:

      Fatal familial insomnia (FFI) is characterized by minimal spongiform change, but notable thalamic atrophy and astrogliosis. Diagnosis of FFI relies heavily on immunohistochemistry and genotyping. In contrast, spongiform change is a hallmark of CJD and Kuru. The majority of CJD cases (85%) are sporadic, while only a small percentage are caused by consuming contaminated food (variant CJD of vCJD).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 144 - The patient, a 25-year-old male who was recently started on risperidone, presents to...

    Incorrect

    • The patient, a 25-year-old male who was recently started on risperidone, presents to the clinic with complaints of decreased libido and gynecomastia. These symptoms may be attributed to the blockade of D-2 receptors in which of the following pathways?

      Your Answer:

      Correct Answer: Tuberoinfundibular

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 145 - Which statement accurately describes neurofibrillary tangles? ...

    Incorrect

    • Which statement accurately describes neurofibrillary tangles?

      Your Answer:

      Correct Answer: They are also seen in dementia pugilistica

      Explanation:

      Amyloid protein is the primary component of amyloid plaques, although they are most commonly linked to Alzheimer’s disease.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 146 - What is a true statement about myelination? ...

    Incorrect

    • What is a true statement about myelination?

      Your Answer:

      Correct Answer: Myelin is produced by glial cells

      Explanation:

      Myelination: The Insulation of Neurons

      Myelin is a fatty material that insulates the axon of a neuron, allowing messages to be sent quickly and without interference. Glial cells, such as oligodendrocytes and Schwann cells, produce myelin in the central and peripheral nervous systems, respectively. Myelination begins in the developing foetus and continues through childhood and adolescence into early adulthood, with the frontal lobes being the last area to myelinate. Myelinated axons appear white, hence the term ‘white matter’ of the brain. Myelination progresses from central to peripheral, caudal to rostral, and dorsal to ventral, with sensory myelination preceding motor myelination.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 147 - Under normal circumstances, which stage of sleep is responsible for the largest portion...

    Incorrect

    • Under normal circumstances, which stage of sleep is responsible for the largest portion of total sleep time?

      Your Answer:

      Correct Answer: Stage II

      Explanation:

      Sleep Stages

      Sleep is divided into two distinct states called rapid eye movement (REM) and non-rapid eye movement (NREM). NREM is subdivided into four stages.

      Sleep stage
      Approx % of time spent in stage
      EEG findings
      Comment

      I
      5%
      Theta waves (4-7 Hz)
      The dozing off stage. Characterized by hypnic jerks: spontaneous myoclonic contractions associated with a sensation of twitching of falling.

      II
      45%
      Theta waves, K complexes and sleep spindles (short bursts of 12-14 Hz activity)
      Body enters a more subdued state including a drop in temperature, relaxed muscles, and slowed breathing and heart rate. At the same time, brain waves show a new pattern and eye movement stops.

      III
      15%
      Delta waves (0-4 Hz)
      Deepest stage of sleep (high waking threshold). The length of stage 3 decreases over the course of the night.

      IV
      15%
      Mixed, predominantly beta
      High dream activity.

      The percentage of REM sleep decreases with age.

      It takes the average person 15-20 minutes to fall asleep, this is called sleep latency (characterised by the onset of stage I sleep). Once asleep one descends through stages I-II and then III-IV (deep stages). After about 90 minutes of sleep one enters REM. The rest of the sleep comprises of cycles through the stages. As the sleep progresses the periods of REM become greater and the periods of NREM become less. During an average night’s sleep one spends 25% of the sleep in REM and 75% in NREM.

      REM sleep has certain characteristics that separate it from NREM

      Characteristics of REM sleep

      – Autonomic instability (variability in heart rate, respiratory rate, and BP)
      – Loss of muscle tone
      – Dreaming
      – Rapid eye movements
      – Penile erection

      Deafness:

      (No information provided on deafness in relation to sleep stages)

    • This question is part of the following fields:

      • Neurosciences
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  • Question 148 - What is the pathway that links the lateral geniculate nucleus to the primary...

    Incorrect

    • What is the pathway that links the lateral geniculate nucleus to the primary visual cortex in the occipital lobe?

      Your Answer:

      Correct Answer: Geniculocalcarine tract

      Explanation:

      White matter is the cabling that links different parts of the CNS together. There are three types of white matter cables: projection tracts, commissural tracts, and association tracts. Projection tracts connect higher centers of the brain with lower centers, commissural tracts connect the two hemispheres together, and association tracts connect regions of the same hemisphere. Some common tracts include the corticospinal tract, which connects the motor cortex to the brainstem and spinal cord, and the corpus callosum, which is the largest white matter fiber bundle connecting corresponding areas of cortex between the hemispheres. Other tracts include the cingulum, superior and inferior occipitofrontal fasciculi, and the superior and inferior longitudinal fasciculi.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 149 - Which enzyme is responsible for the conversion of tyrosine to dihydroxyphenylalanine? ...

    Incorrect

    • Which enzyme is responsible for the conversion of tyrosine to dihydroxyphenylalanine?

      Your Answer:

      Correct Answer: Tyrosine hydroxylase

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 150 - Which of the following is enlarged in individuals with schizophrenia? ...

    Incorrect

    • Which of the following is enlarged in individuals with schizophrenia?

      Your Answer:

      Correct Answer: The ventricles

      Explanation:

      Ventricular enlargement is a common finding in individuals with schizophrenia.

      Schizophrenia is a pathology that is characterized by a number of structural and functional brain alterations. Structural alterations include enlargement of the ventricles, reductions in total brain and gray matter volume, and regional reductions in the amygdala, parahippocampal gyrus, and temporal lobes. Antipsychotic treatment may be associated with gray matter loss over time, and even drug-naïve patients show volume reductions. Cerebral asymmetry is also reduced in affected individuals and healthy relatives. Functional alterations include diminished activation of frontal regions during cognitive tasks and increased activation of temporal regions during hallucinations. These findings suggest that schizophrenia is associated with both macroscopic and functional changes in the brain.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 151 - Which condition is typically associated with a flattened EEG trace? ...

    Incorrect

    • Which condition is typically associated with a flattened EEG trace?

      Your Answer:

      Correct Answer: Huntington's

      Explanation:

      Electroencephalography

      Electroencephalography (EEG) is a clinical test that records the brain’s spontaneous electrical activity over a short period of time using multiple electrodes placed on the scalp. It is mainly used to rule out organic conditions and can help differentiate dementia from other disorders such as metabolic encephalopathies, CJD, herpes encephalitis, and non-convulsive status epilepticus. EEG can also distinguish possible psychotic episodes and acute confusional states from non-convulsive status epilepticus.

      Not all abnormal EEGs represent an underlying condition, and psychotropic medications can affect EEG findings. EEG abnormalities can also be triggered purposely by activation procedures such as hyperventilation, photic stimulation, certain drugs, and sleep deprivation.

      Specific waveforms are seen in an EEG, including delta, theta, alpha, sigma, beta, and gamma waves. Delta waves are found frontally in adults and posteriorly in children during slow wave sleep, and excessive amounts when awake may indicate pathology. Theta waves are generally seen in young children, drowsy and sleeping adults, and during meditation. Alpha waves are seen posteriorly when relaxed and when the eyes are closed, and are also seen in meditation. Sigma waves are bursts of oscillatory activity that occur in stage 2 sleep. Beta waves are seen frontally when busy of concentrating, and gamma waves are seen in advanced/very experienced meditators.

      Certain conditions are associated with specific EEG changes, such as nonspecific slowing in early CJD, low voltage EEG in Huntington’s, diffuse slowing in encephalopathy, and reduced alpha and beta with increased delta and theta in Alzheimer’s.

      Common epileptiform patterns include spikes, spike/sharp waves, and spike-waves. Medications can have important effects on EEG findings, with clozapine decreasing alpha and increasing delta and theta, lithium increasing all waveforms, lamotrigine decreasing all waveforms, and valproate having inconclusive effects on delta and theta and increasing beta.

      Overall, EEG is a useful tool in clinical contexts for ruling out organic conditions and differentiating between various disorders.

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      • Neurosciences
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  • Question 152 - A 65-year-old individual presents with a sudden onset of horizontal diplopia. Upon examination,...

    Incorrect

    • A 65-year-old individual presents with a sudden onset of horizontal diplopia. Upon examination, you note that they have an inability to move their left eye laterally. Which cranial nerve is most likely affected?

      Your Answer:

      Correct Answer: VI

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 153 - What is a component of the hypothalamus in terms of neuroanatomy? ...

    Incorrect

    • What is a component of the hypothalamus in terms of neuroanatomy?

      Your Answer:

      Correct Answer: Mammillary bodies

      Explanation:

      The striatum is composed of the caudate nucleus and putamen, which are part of the basal ganglia. The basal ganglia is the largest subcortical structure in the brain and consists of a group of grey matter nuclei located in the subcortical area. In contrast, the mammillary bodies are small round bodies that are part of the hypothalamus and play a crucial role in the Papez circuit as a component of the limbic system.

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      • Neurosciences
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  • Question 154 - Which reflex involves the oculomotor, trochlear, and abducent nerve in its motor component?...

    Incorrect

    • Which reflex involves the oculomotor, trochlear, and abducent nerve in its motor component?

      Your Answer:

      Correct Answer: Vestibulo-ocular

      Explanation:

      Cranial Nerve Reflexes

      When it comes to questions on cranial nerve reflexes, it is important to match the reflex to the nerves involved. Here are some examples:

      – Pupillary light reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Accommodation reflex: involves the optic nerve (sensory) and oculomotor nerve (motor).
      – Jaw jerk: involves the trigeminal nerve (sensory and motor).
      – Corneal reflex: involves the trigeminal nerve (sensory) and facial nerve (motor).
      – Vestibulo-ocular reflex: involves the vestibulocochlear nerve (sensory) and oculomotor, trochlear, and abducent nerves (motor).

      Another example of a cranial nerve reflex is the gag reflex, which involves the glossopharyngeal nerve (sensory) and the vagus nerve (motor). This reflex is important for protecting the airway from foreign objects of substances that may trigger a gag reflex. It is also used as a diagnostic tool to assess the function of these nerves.

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      • Neurosciences
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  • Question 155 - What is the term used to describe an intense and brief emotional reaction...

    Incorrect

    • What is the term used to describe an intense and brief emotional reaction to a minor trigger?

      Your Answer:

      Correct Answer: Emotional lability

      Explanation:

      Multiple Sclerosis: An Overview

      Multiple sclerosis is a neurological disorder that is classified into three categories: primary progressive, relapsing-remitting, and secondary progressive. Primary progressive multiple sclerosis affects 5-10% of patients and is characterized by a steady progression with no remissions. Relapsing-remitting multiple sclerosis affects 20-30% of patients and presents with a relapsing-remitting course but does not lead to serious disability. Secondary progressive multiple sclerosis affects 60% of patients and initially presents with a relapsing-remitting course but is then followed by a phase of progressive deterioration.

      The disorder typically begins between the ages of 20 and 40 and is characterized by multiple demyelinating lesions that have a preference for the optic nerves, cerebellum, brainstem, and spinal cord. Patients with multiple sclerosis present with a variety of neurological signs that reflect the presence and distribution of plaques. Ocular features of multiple sclerosis include optic neuritis, internuclear ophthalmoplegia, and ocular motor cranial neuropathy.

      Multiple sclerosis is more common in women than in men and is seen with increasing frequency as the distance from the equator increases. It is believed to be caused by a combination of genetic and environmental factors, with monozygotic concordance at 25%. Overall, multiple sclerosis is a predominantly white matter disease that can have a significant impact on a patient’s quality of life.

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      • Neurosciences
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  • Question 156 - What is the typical artery that is blocked in cases of Alexia without...

    Incorrect

    • What is the typical artery that is blocked in cases of Alexia without agraphia?

      Your Answer:

      Correct Answer: Posterior cerebral artery

      Explanation:

      Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 157 - Which neuroimaging technique that maps cortical activation uses the non-invasive BOLD method? ...

    Incorrect

    • Which neuroimaging technique that maps cortical activation uses the non-invasive BOLD method?

      Your Answer:

      Correct Answer: Functional MRI (fMRI)

      Explanation:

      The BOLD technique is used by fMRI to non-invasively map cortical activation, while PET and SPECT require the administration of a radioactive isotope and are invasive. Although all three magnetic imaging techniques are non-invasive, fMRI stands out for its use of the BOLD technique.

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      • Neurosciences
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  • Question 158 - Through which opening in the skull does the cranial nerve exit, which is...

    Incorrect

    • Through which opening in the skull does the cranial nerve exit, which is known as the internal auditory canal?

      Your Answer:

      Correct Answer: Vestibulocochlear (VIII)

      Explanation:

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 159 - What is a true statement about the neocortex? ...

    Incorrect

    • What is a true statement about the neocortex?

      Your Answer:

      Correct Answer: It contains both pyramidal and nonpyramidal cells

      Explanation:

      The Cerebral Cortex and Neocortex

      The cerebral cortex is the outermost layer of the cerebral hemispheres and is composed of three parts: the archicortex, paleocortex, and neocortex. The neocortex accounts for 90% of the cortex and is involved in higher functions such as thought and language. It is divided into 6-7 layers, with two main cell types: pyramidal cells and nonpyramidal cells. The surface of the neocortex is divided into separate areas, each given a number by Brodmann (e.g. Brodmann’s area 17 is the primary visual cortex). The surface is folded to increase surface area, with grooves called sulci and ridges called gyri. The neocortex is responsible for higher cognitive functions and is essential for human consciousness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 160 - What is a true statement about the planum temporale? ...

    Incorrect

    • What is a true statement about the planum temporale?

      Your Answer:

      Correct Answer: Planum temporale asymmetry is more prominent in males than in females

      Explanation:

      Cerebral Asymmetry in Planum Temporale and its Implications in Language and Auditory Processing

      The planum temporale, a triangular region in the posterior superior temporal gyrus, is a highly lateralized brain structure involved in language and music processing. Studies have shown that the planum temporale is up to ten times larger in the left cerebral hemisphere than the right, with this asymmetry being more prominent in men. This asymmetry can be observed in gestation and is present in up to 70% of right-handed individuals.

      Recent research suggests that the planum temporale also plays an important role in auditory processing, specifically in representing the location of sounds in space. However, reduced planum temporale asymmetry has been observed in individuals with dyslexia, stuttering, and schizophrenia. These findings highlight the importance of cerebral asymmetry in the planum temporale and its implications in language and auditory processing.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 161 - What type of apraxia is indicated when a patient is given a pencil...

    Incorrect

    • What type of apraxia is indicated when a patient is given a pencil during a neurological examination and they attempt to use it to brush their teeth after looking at it for a minute?

      Your Answer:

      Correct Answer: Ideomotor

      Explanation:

      The inability to carry out complex instructions is referred to as Ideational Apraxia, while the inability to perform previously learned actions with the appropriate tools is known as Ideomotor Apraxia.

      Apraxia: Understanding the Inability to Carry Out Learned Voluntary Movements

      Apraxia is a neurological condition that affects a person’s ability to carry out learned voluntary movements. It is important to note that this condition assumes that everything works and the person is not paralyzed. There are different types of apraxia, each with its own set of symptoms and characteristics.

      Limb kinetic apraxia is a type of apraxia that affects a person’s ability to make fine of delicate movements. This can include tasks such as buttoning a shirt of tying shoelaces.

      Ideomotor apraxia, on the other hand, is an inability to carry out learned tasks when given the necessary objects. For example, a person with ideomotor apraxia may try to write with a hairbrush instead of using it to brush their hair.

      Constructional apraxia affects a person’s ability to copy a picture of combine parts of something to form a whole. This can include tasks such as building a puzzle of drawing a picture.

      Ideational apraxia is an inability to follow a sequence of actions in the correct order. For example, a person with ideational apraxia may struggle to take a match out of a box and strike it with their left hand.

      Finally, oculomotor apraxia affects a person’s ability to control eye movements. This can make it difficult for them to track moving objects of read smoothly.

      Overall, apraxia can have a significant impact on a person’s ability to carry out everyday tasks. However, with the right support and treatment, many people with apraxia are able to improve their abilities and maintain their independence.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 162 - What is the extracellular ion that contributes to the resting membrane potential of...

    Incorrect

    • What is the extracellular ion that contributes to the resting membrane potential of a neuron due to its high concentration?

      Your Answer:

      Correct Answer: Na

      Explanation:

      Understanding Action Potentials in Neurons and Muscle Cells

      The membrane potential is a crucial aspect of cell physiology, and it exists across the plasma membrane of most cells. However, in neurons and muscle cells, this membrane potential can change over time. When a cell is not stimulated, it is in a resting state, and the inside of the cell is negatively charged compared to the outside. This resting membrane potential is typically around -70mV, and it is maintained by the Na/K pump, which maintains a high concentration of Na outside and K inside the cell.

      To trigger an action potential, the membrane potential must be raised to around -55mV. This can occur when a neurotransmitter binds to the postsynaptic neuron and opens some ion channels. Once the membrane potential reaches -55mV, a cascade of events is initiated, leading to the opening of a large number of Na channels and causing the cell to depolarize. As the membrane potential reaches around +40 mV, the Na channels close, and the K gates open, allowing K to flood out of the cell and causing the membrane potential to fall back down. This process is irreversible and is critical for the transmission of signals in neurons and the contraction of muscle cells.

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      • Neurosciences
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  • Question 163 - A 50-year-old woman presents to you with concerns that she may be losing...

    Incorrect

    • A 50-year-old woman presents to you with concerns that she may be losing her mind. She reports experiencing peculiar odors, such as burnt rubber, and frequently experiences feelings of 'jamais vu'. However, no one else detects any unusual smells during these episodes. She remains fully conscious and can recall the events vividly. What is the probable diagnosis?

      Your Answer:

      Correct Answer: Simple partial seizure

      Explanation:

      If the individual were to experience impaired consciousness during the attack, this would be classified as a complex partial seizure. However, based on the current symptoms, it appears to be a simple partial seizure with retained consciousness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 164 - What is the causative agent of progressive multifocal leukoencephalopathy (PML), a common opportunistic...

    Incorrect

    • What is the causative agent of progressive multifocal leukoencephalopathy (PML), a common opportunistic CNS infection seen in individuals with AIDS?

      Your Answer:

      Correct Answer: John Cunningham virus (JCV)

      Explanation:

      JCV is the cause of progressive multifocal leukoencephalopathy (PML) and typically affects individuals with weakened immune systems. Cryptococcus is a fungus that can lead to meningitis and meningoencephalitis in those with HIV/AIDS. CMV infection can be extremely dangerous for those who are immunocompromised. EBV is responsible for infectious mononucleosis, also known as glandular fever. Herpes simplex virus has two variations, HSV-1 and HSV-2, which can cause oral lesions (commonly known as cold sores) of genital lesions, respectively.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 165 - To which category does the dentate gyrus belong? ...

    Incorrect

    • To which category does the dentate gyrus belong?

      Your Answer:

      Correct Answer: Hippocampus

      Explanation:

      The dentate gyrus is a component of the hippocampal formation.

      A gyrus is a ridge on the cerebral cortex, and there are several important gyri to be aware of in exams. These include the angular gyrus in the parietal lobe for language, mathematics, and cognition; the cingulate gyrus adjacent to the corpus callosum for emotion, learning, and memory; the fusiform gyrus in the temporal lobe for face and body recognition, as well as word and number recognition; the precentral gyrus in the frontal lobe for voluntary movement control; the postcentral gyrus in the parietal lobe for touch; the lingual gyrus in the occipital lobe for dreaming and word recognition; the superior frontal gyrus in the frontal lobe for laughter and self-awareness; the superior temporal gyrus in the temporal lobe for language and sensation of sound; the parahippocampal gyrus surrounding the hippocampus for memory; and the dentate gyrus in the hippocampus for the formation of episodic memory.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 166 - What is a true statement about the cerebellum? ...

    Incorrect

    • What is a true statement about the cerebellum?

      Your Answer:

      Correct Answer: The vestibulocerebellum controls balance and spatial orientation

      Explanation:

      The Cerebellum: Anatomy and Function

      The cerebellum is a part of the brain that consists of two hemispheres and a median vermis. It is separated from the cerebral hemispheres by the tentorium cerebelli and connected to the brain stem by the cerebellar peduncles. Anatomically, it is divided into three lobes: the flocculonodular lobe, anterior lobe, and posterior lobe. Functionally, it is divided into three regions: the vestibulocerebellum, spinocerebellum, and cerebrocerebellum.

      The vestibulocerebellum, located in the flocculonodular lobe, is responsible for balance and spatial orientation. The spinocerebellum, located in the medial section of the anterior and posterior lobes, is involved in fine-tuned body movements. The cerebrocerebellum, located in the lateral section of the anterior and posterior lobes, is involved in planning movement and the conscious assessment of movement.

      Overall, the cerebellum plays a crucial role in motor coordination and control. Its different regions and lobes work together to ensure smooth and precise movements of the body.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 167 - What is a true statement about cerebrovascular accidents? ...

    Incorrect

    • What is a true statement about cerebrovascular accidents?

      Your Answer:

      Correct Answer: Cerebral infarction commonly occurs during sleep

      Explanation:

      It is widely acknowledged that women who have pre-existing cardiovascular disease should avoid taking oral contraceptives due to the increased risk of stroke and DVTs.

      Cerebrovascular accidents (CVA), also known as strokes, are defined by the World Health Organization as a sudden onset of focal neurological symptoms lasting more than 24 hours and presumed to be of vascular origin. Strokes can be caused by either infarction of hemorrhage, with infarction being more common. Hemorrhagic strokes tend to be more severe. Intracranial hemorrhage can be primary, caused mainly by hypertension, of subarachnoid, caused by the rupture of an aneurysm of angioma. Primary intracranial hemorrhage is most common in individuals aged 60-80 and often occurs during exertion. Infarction can be caused by thrombosis of embolism, with thrombosis being more common. Atherosclerosis, often caused by hypertension, is the main cause of infarction. CT scanning is the preferred diagnostic tool during the first 48 hours after a stroke as it can distinguish between infarcts and hemorrhages. Recovery from embolism is generally quicker and more complete than from thrombosis due to the availability of collateral channels.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 168 - What is a minimally invasive method that utilizes radioisotopes? ...

    Incorrect

    • What is a minimally invasive method that utilizes radioisotopes?

      Your Answer:

      Correct Answer: SPECT

      Explanation:

      Neuroimaging techniques can be divided into structural and functional types, although this distinction is becoming less clear as new techniques emerge. Structural techniques include computed tomography (CT) and magnetic resonance imaging (MRI), which use x-rays and magnetic fields, respectively, to produce images of the brain’s structure. Functional techniques, on the other hand, measure brain activity by detecting changes in blood flow of oxygen consumption. These include functional MRI (fMRI), emission tomography (PET and SPECT), perfusion MRI (pMRI), and magnetic resonance spectroscopy (MRS). Some techniques, such as diffusion tensor imaging (DTI), combine both structural and functional information to provide a more complete picture of the brain’s anatomy and function. DTI, for example, uses MRI to estimate the paths that water takes as it diffuses through white matter, allowing researchers to visualize white matter tracts.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 169 - Which statement about the glossopharyngeal nerve is false? ...

    Incorrect

    • Which statement about the glossopharyngeal nerve is false?

      Your Answer:

      Correct Answer: Controls the muscles of mastication

      Explanation:

      The trigeminal nerve is responsible for controlling the muscles involved in chewing, while the glossopharyngeal nerves consist of both motor and sensory fibers that originate from nuclei in the medulla oblongata. The motor fibers of the glossopharyngeal nerves stimulate the pharyngeal muscles and parotid gland secretory cells, while the sensory fibers transmit impulses from the posterior third of the tongue, tonsils, and pharynx to the cerebral cortex.

      Overview of Cranial Nerves and Their Functions

      The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

      The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

      The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

      The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

      The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

      The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

      The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

      The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 170 - What is the name of the dural reflection that acts as a boundary...

    Incorrect

    • What is the name of the dural reflection that acts as a boundary between the cerebellum and the occipital lobes of the cerebrum?

      Your Answer:

      Correct Answer: Tentorium cerebelli

      Explanation:

      Dura Mater

      The dura mater is one of the three membranes, known as meninges, that cover the brain and spinal cord. It is the outermost and most fibrous layer, with the pia mater and arachnoid mater making up the remaining layers. The pia mater is the innermost layer.

      The dura mater is folded at certain points, including the falx cerebri, which separates the two cerebral hemispheres of the brain, the tentorium cerebelli, which separates the cerebellum from the cerebrum, the falx cerebelli, which separates the cerebellar hemispheres, and the sellar diaphragm, which covers the pituitary gland and forms a roof over the hypophyseal fossa.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 171 - Which symptom is unlikely to be the first one noticed in a person...

    Incorrect

    • Which symptom is unlikely to be the first one noticed in a person with normal pressure hydrocephalus?

      Your Answer:

      Correct Answer: Headache

      Explanation:

      Headache and other symptoms commonly associated with hydrocephalus may not be present in normal pressure hydrocephalus due to the fact that intracranial pressure does not typically remain elevated.

      Normal Pressure Hydrocephalus

      Normal pressure hydrocephalus is a type of chronic communicating hydrocephalus, which occurs due to the impaired reabsorption of cerebrospinal fluid (CSF) by the arachnoid villi. Although the CSF pressure is typically high, it remains within the normal range, and therefore, it does not cause symptoms of high intracranial pressure (ICP) such as headache and nausea. Instead, patients with normal pressure hydrocephalus usually present with a classic triad of symptoms, including incontinence, gait ataxia, and dementia, which is often referred to as wet, wobbly, and wacky. Unfortunately, this condition is often misdiagnosed as Parkinson’s of Alzheimer’s disease.

      The classic triad of normal pressure hydrocephalus, also known as Hakim’s triad, includes gait instability, urinary incontinence, and dementia. On the other hand, non-communicating hydrocephalus results from the obstruction of CSF flow in the third of fourth ventricle, which causes symptoms of raised intracranial pressure, such as headache, vomiting, hypertension, bradycardia, altered consciousness, and papilledema.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 172 - What substance hinders the secretion of growth hormone in the brain? ...

    Incorrect

    • What substance hinders the secretion of growth hormone in the brain?

      Your Answer:

      Correct Answer: Somatostatin

      Explanation:

      Pancreatic Hormones: Functions and Production

      The pancreas serves as both an exocrine and endocrine gland. Its endocrine function involves the production of four distinct hormones from the islets of Langerhans. These hormones include somatostatin, insulin, pancreatic polypeptide, and glucagon. Somatostatin is also produced by the brain, specifically the hypothalamus, where it inhibits the secretion of thyroid-stimulating hormone and growth hormone from somatotroph cells.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 173 - What type of dysarthria is typically caused by widespread damage to the upper...

    Incorrect

    • What type of dysarthria is typically caused by widespread damage to the upper motor neurons?

      Your Answer:

      Correct Answer: Spastic dysarthria

      Explanation:

      Dysarthria is a speech disorder that affects the volume, rate, tone, of quality of spoken language. There are different types of dysarthria, each with its own set of features, associated conditions, and localisation. The types of dysarthria include spastic, flaccid, hypokinetic, hyperkinetic, and ataxic.

      Spastic dysarthria is characterised by explosive and forceful speech at a slow rate and is associated with conditions such as pseudobulbar palsy and spastic hemiplegia.

      Flaccid dysarthria, on the other hand, is characterised by a breathy, nasal voice and imprecise consonants and is associated with conditions such as myasthenia gravis.

      Hypokinetic dysarthria is characterised by slow, quiet speech with a tremor and is associated with conditions such as Parkinson’s disease.

      Hyperkinetic dysarthria is characterised by a variable rate, inappropriate stoppages, and a strained quality and is associated with conditions such as Huntington’s disease, Sydenham’s chorea, and tardive dyskinesia.

      Finally, ataxic dysarthria is characterised by rapid, monopitched, and slurred speech and is associated with conditions such as Friedreich’s ataxia and alcohol abuse. The localisation of each type of dysarthria varies, with spastic and flaccid dysarthria affecting the upper and lower motor neurons, respectively, and hypokinetic, hyperkinetic, and ataxic dysarthria affecting the extrapyramidal and cerebellar regions of the brain.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 174 - From which structure does the mesolimbic pathway project to the nucleus accumbens? ...

    Incorrect

    • From which structure does the mesolimbic pathway project to the nucleus accumbens?

      Your Answer:

      Correct Answer: Midbrain

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 175 - Which of the following is not a characteristic of non-dominant parietal lesions? ...

    Incorrect

    • Which of the following is not a characteristic of non-dominant parietal lesions?

      Your Answer:

      Correct Answer: Agraphia

      Explanation:

      Non-Dominant Parietal Lobe Dysfunction

      The non-dominant parietal lobe is typically the right lobe in most individuals. Dysfunction in this area can lead to various symptoms, including the inability to recognize one’s own illness (anosognosia), neglect of half the body (hemiasomatognosia), difficulty dressing (dressing apraxia), trouble with spatial awareness and construction (constructional dyspraxia), difficulty recognizing familiar places (geographical agnosia), and altered perception of sensory stimuli (allesthesia). It’s important to note that agraphia, a symptom seen in Gerstmann’s syndrome, is caused by dysfunction in the dominant parietal lobe, not the non-dominant lobe.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 176 - A 65-year-old woman is experiencing memory difficulties and has been diagnosed with Alzheimer's...

    Incorrect

    • A 65-year-old woman is experiencing memory difficulties and has been diagnosed with Alzheimer's disease. Which anatomical structure is most likely to exhibit atrophy in this scenario?

      Your Answer:

      Correct Answer: Hippocampus

      Explanation:

      The frontal lobe is located at the front of the cerebrum and is responsible for managing executive functions and working memory. The hippocampus plays a role in spatial navigation and the consolidation of short term memory to long term memory, but is often the first region of the brain to suffer damage in Alzheimer’s disease. The corpus callosum is a bundle of nerve fibers that connects the left and right cerebral hemispheres, facilitating communication between them. The thalamus is a symmetrical midline structure that relays sensory and motor signals to the cerebral cortex, while also regulating consciousness, alertness, and sleep. Broca’s area, which is typically located in the inferior frontal gyrus, is a key region involved in language production.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 177 - Which receptors are affected by fluoxetine that are believed to be responsible for...

    Incorrect

    • Which receptors are affected by fluoxetine that are believed to be responsible for causing insomnia?

      Your Answer:

      Correct Answer: 5-HT2

      Explanation:

      Serotonin (5-hydroxytryptamine, 5-HT) receptors are primarily G protein receptors, except for 5-HT3, which is a ligand-gated receptor. It is important to remember that 5-HT3 is most commonly associated with nausea. Additionally, 5-HT7 is linked to circadian rhythms. The stimulation of 5-HT2 receptors is believed to be responsible for the side effects of insomnia, agitation, and sexual dysfunction that are associated with the use of selective serotonin reuptake inhibitors (SSRIs).

    • This question is part of the following fields:

      • Neurosciences
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  • Question 178 - Which condition is commonly linked to pronator drift? ...

    Incorrect

    • Which condition is commonly linked to pronator drift?

      Your Answer:

      Correct Answer: Spasticity

      Explanation:

      Spasticity is the correct answer as pronator drift is a sign of upper motor neuron lesions, while the other options are indicative of lower motor neuron lesions.

      Understanding Pronator Drift in Neurological Examinations

      Pronator drift is a neurological sign that is commonly observed during a medical examination. This sign is elicited by asking the patient to flex their arms forward at a 90-degree angle to the shoulders, supinate their forearms, close their eyes, and maintain the position. In a normal scenario, the position should remain unchanged. However, in some cases, one arm may be seen to pronate.

      Pronator drift is typically caused by an upper motor neuron lesion. There are various underlying conditions that can lead to this type of lesion, including stroke, multiple sclerosis, and brain tumors. The presence of pronator drift can help healthcare professionals to identify the location and severity of the lesion, as well as to determine the appropriate course of treatment.

      Overall, understanding pronator drift is an important aspect of neurological examinations. By recognizing this sign and its underlying causes, healthcare professionals can provide more accurate diagnoses and develop effective treatment plans for their patients.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 179 - What are some common symptoms that are typically observed in the initial phases...

    Incorrect

    • What are some common symptoms that are typically observed in the initial phases of Alzheimer's disease?

      Your Answer:

      Correct Answer: Hippocampal atrophy

      Explanation:

      The medial temporal lobe, comprising the hippocampus and parahippocampal gyrus, exhibits the earliest neuropathological alterations.

      Alzheimer’s disease is characterized by both macroscopic and microscopic changes in the brain. Macroscopic changes include cortical atrophy, ventricular dilation, and depigmentation of the locus coeruleus. Microscopic changes include the presence of senile plaques, neurofibrillary tangles, gliosis, degeneration of the nucleus of Meynert, and Hirano bodies. Senile plaques are extracellular deposits of beta amyloid in the gray matter of the brain, while neurofibrillary tangles are intracellular inclusion bodies that consist primarily of hyperphosphorylated tau. Gliosis is marked by increases in activated microglia and reactive astrocytes near the sites of amyloid plaques. The nucleus of Meynert degenerates in Alzheimer’s, resulting in a decrease in acetylcholine in the brain. Hirano bodies are actin-rich, eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure and are regarded as a nonspecific manifestation of neuronal degeneration. These changes in the brain contribute to the cognitive decline and memory loss seen in Alzheimer’s disease.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 180 - A 56-year-old woman experiences a stroke caused by a ruptured berry aneurysm in...

    Incorrect

    • A 56-year-old woman experiences a stroke caused by a ruptured berry aneurysm in the right middle cerebral artery. She frequently collides with objects but denies any visual impairment.
      What is the probable diagnosis?

      Your Answer:

      Correct Answer: Anton syndrome

      Explanation:

      Anton-Babinski syndrome, also known as Anton syndrome of Anton’s blindness, is a rare condition caused by brain damage in the occipital lobe. Individuals with this syndrome are unable to see due to cortical blindness, but they insist that they can see despite evidence to the contrary. This is because they confabulate, of make up explanations for their inability to see. The syndrome is typically a result of a stroke, but can also occur after a head injury.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 181 - What are the potential consequences of damage to the dominant cerebral hemisphere? ...

    Incorrect

    • What are the potential consequences of damage to the dominant cerebral hemisphere?

      Your Answer:

      Correct Answer: Right-left disorientation

      Explanation:

      Hemispheric Damage: Selected Deficits in Dominant and Non-Dominant Hemispheres

      Many functions are performed by both the right and left cerebral hemispheres. However, certain functions are localized, and damage to a specific hemisphere can result in deficits in specific areas. The following table outlines selected deficits seen in hemispheric damage.

      Dominant Hemisphere (usually left):
      – Aphasia: difficulty with language and communication
      – Limb apraxia: difficulty with skilled movements of limbs
      – Finger agnosia: difficulty recognizing fingers
      – Dysgraphia (aphasic): difficulty with writing and spelling
      – Dyscalculia (number alexia): difficulty with reading and understanding numbers
      – Constructional apraxia: difficulty with constructing objects of copying designs
      – Right-left disorientation: difficulty distinguishing left from right

      Non-Dominant Hemisphere (usually right):
      – Visuospatial deficits: difficulty with spatial perception and orientation
      – Impaired visual perception: difficulty with recognizing and interpreting visual information
      – Neglect: lack of awareness of one side of the body of environment
      – Dysgraphia (spatial neglect): difficulty with writing on one side of the page
      – Dyscalculia (spatial): difficulty with spatial reasoning and understanding of shapes and sizes
      – Constructional apraxia (Gestalt): difficulty with assembling parts into a whole
      – Dressing apraxia: difficulty with dressing oneself
      – Anosognosia: lack of awareness of denial of one’s own deficits of condition.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 182 - A 60-year-old patient complains of headaches which are worse in the morning and...

    Incorrect

    • A 60-year-old patient complains of headaches which are worse in the morning and have been present for 2 months. They have been told by their GP it is probably 'tension headache'. Which of the following symptoms is suggestive of a more sinister pathology?

      Your Answer:

      Correct Answer: Pain worse on bending down

      Explanation:

      Indicators of a potentially serious headache are:

      – Developing a headache for the first time after the age of 50
      – Sudden and severe headache (often described as a thunderclap headache)
      – Accompanying symptoms such as redness in the eye and seeing halos around lights
      – Headache that gets worse with physical activity of straining (such as during a Valsalva maneuver)

      Cerebral Tumours

      The most common brain tumours in adults, listed in order of frequency, are metastatic tumours, glioblastoma multiforme, anaplastic astrocytoma, and meningioma. On the other hand, the most common brain tumours in children, listed in order of frequency, are astrocytoma, medulloblastoma, and ependymoma.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 183 - A senior citizen is experiencing sedation during lurasidone dose titration. What is the...

    Incorrect

    • A senior citizen is experiencing sedation during lurasidone dose titration. What is the medication's minimum effective dose?

      Your Answer:

      Correct Answer: 37 mg

      Explanation:

      Lurasidone may cause akathisia and sedation as common side effects, which can vary based on the dosage. Its metabolic profile is neutral. However, doses lower than 37 mg are unlikely to produce desired results.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 184 - What illness is brought about by prions? ...

    Incorrect

    • What illness is brought about by prions?

      Your Answer:

      Correct Answer: Creutzfeldt-Jakob disease

      Explanation:

      Prions are responsible for causing Creutzfeldt-Jakob disease (CJD), a fatal and uncommon condition that leads to progressive neurodegeneration. The disease is characterized by swiftly advancing dementia as one of its primary symptoms.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 185 - What is the function of the Nissl substance within a neuron? ...

    Incorrect

    • What is the function of the Nissl substance within a neuron?

      Your Answer:

      Correct Answer: Protein synthesis

      Explanation:

      Melanin

      Melanin is a pigment found in various parts of the body, including the skin, hair, and eyes. It is produced by specialized cells called melanocytes, which are located in the skin’s basal layer. The function of melanin in the body is not fully understood, but it is thought to play a role in protecting the skin from the harmful effects of ultraviolet (UV) radiation from the sun. Additionally, melanin may be a by-product of neurotransmitter synthesis, although this function is not well established. Overall, the role of melanin in the body is an area of ongoing research.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 186 - What substances are found at higher levels in individuals with depression and bipolar...

    Incorrect

    • What substances are found at higher levels in individuals with depression and bipolar affective disorder?

      Your Answer:

      Correct Answer: Cortisol

      Explanation:

      HPA Axis Dysfunction in Mood Disorders

      The HPA axis, which includes regulatory neural inputs and a feedback loop involving the hypothalamus, pituitary, and adrenal glands, plays a central role in the stress response. Excessive secretion of cortisol, a glucocorticoid hormone, can lead to disruptions in cellular functioning and widespread physiologic dysfunction. Dysregulation of the HPA axis is implicated in mood disorders such as depression and bipolar affective disorder.

      In depressed patients, cortisol levels often do not decrease as expected in response to the administration of dexamethasone, a synthetic corticosteroid. This abnormality in the dexamethasone suppression test is thought to be linked to genetic of acquired defects of glucocorticoid receptors. Tricyclic antidepressants have been shown to increase expression of glucocorticoid receptors, whereas this is not the case for SSRIs.

      Early adverse experiences can produce long standing changes in HPA axis regulation, indicating a possible neurobiological mechanism whereby childhood trauma could be translated into increased vulnerability to mood disorder. In major depression, there is hypersecretion of cortisol, corticotropin-releasing factor (CRF), and ACTH, and associated adrenocortical enlargement. HPA abnormalities have also been found in other psychiatric disorders including Alzheimer’s and PTSD.

      In bipolar disorder, dysregulation of ACTH and cortisol response after CRH stimulation have been reported. Abnormal DST results are found more often during depressive episodes in the course of bipolar disorder than in unipolar disorder. Reduced pituitary volume secondary to LHPA stimulation, resulting in pituitary hypoactivity, has been observed in bipolar patients.

      Overall, HPA axis dysfunction is implicated in mood disorders, and understanding the underlying mechanisms may lead to new opportunities for treatments.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 187 - What is a substance that activates GABA-B receptors called? ...

    Incorrect

    • What is a substance that activates GABA-B receptors called?

      Your Answer:

      Correct Answer: Baclofen

      Explanation:

      Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 188 - Which structure is thought to play a major role in processing rewards? ...

    Incorrect

    • Which structure is thought to play a major role in processing rewards?

      Your Answer:

      Correct Answer: Nucleus accumbens

      Explanation:

      Drug addiction is closely linked to reward processing, which is primarily regulated by the nucleus accumbens and the ventral tegmental area (VTA).

      The Basal Ganglia: Functions and Disorders

      The basal ganglia are a group of subcortical structures that play a crucial role in controlling movement and some cognitive processes. The components of the basal ganglia include the striatum (caudate, putamen, nucleus accumbens), subthalamic nucleus, globus pallidus, and substantia nigra (divided into pars compacta and pars reticulata). The putamen and globus pallidus are collectively referred to as the lenticular nucleus.

      The basal ganglia are connected in a complex loop, with the cortex projecting to the striatum, the striatum to the internal segment of the globus pallidus, the internal segment of the globus pallidus to the thalamus, and the thalamus back to the cortex. This loop is responsible for regulating movement and cognitive processes.

      However, problems with the basal ganglia can lead to several conditions. Huntington’s chorea is caused by degeneration of the caudate nucleus, while Wilson’s disease is characterized by copper deposition in the basal ganglia. Parkinson’s disease is associated with degeneration of the substantia nigra, and hemiballism results from damage to the subthalamic nucleus.

      In summary, the basal ganglia are a crucial part of the brain that regulate movement and some cognitive processes. Disorders of the basal ganglia can lead to significant neurological conditions that affect movement and other functions.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 189 - In which region of the CNS do serotonergic neurons have the highest concentration...

    Incorrect

    • In which region of the CNS do serotonergic neurons have the highest concentration of cell bodies?

      Your Answer:

      Correct Answer: Raphe nuclei

      Explanation:

      The raphe nuclei in the brainstem are the primary location of serotonergic neuronal cell bodies in the central nervous system (CNS), which project to the brain and spinal cord. Noradrenaline is synthesised by the locus coeruleus, located in the pons. Dopamine is produced in the substantia nigra and ventral tegmental area in the midbrain. While the majority of serotonin is found in enterochromaffin cells in the gastrointestinal (GI) tract, this is not considered part of the CNS. These neurotransmitters play important roles in various physiological and psychological processes.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 190 - What is the structure that divides which parts of the brain? ...

    Incorrect

    • What is the structure that divides which parts of the brain?

      Your Answer:

      Correct Answer: The lateral ventricles

      Explanation:

      The septum pellucidum is a thin layer that divides the front sections of the left and right lateral ventricles in the brain. It extends as a flat structure from the corpus callosum to the fornix.

      Dementia Pugilistica: A Neurodegenerative Condition Resulting from Neurotrauma

      Dementia pugilistica, also known as chronic traumatic encephalopathy (CTE), is a neurodegenerative condition that results from neurotrauma. It is commonly seen in boxers and NFL players, but can also occur in anyone with neurotrauma. The condition is characterized by symptoms such as gait ataxia, slurred speech, impaired hearing, tremors, disequilibrium, neurobehavioral disturbances, and progressive cognitive decline.

      Most cases of dementia pugilistica present with early onset cognitive deficits, and behavioral signs exhibited by patients include aggression, suspiciousness, paranoia, childishness, hypersexuality, depression, and restlessness. The progression of the condition leads to more prominent behavioral symptoms such as difficulty with impulse control, irritability, inappropriateness, and explosive outbursts of aggression.

      Neuropathological abnormalities have been identified in CTE, with the most unique feature being the abnormal accumulation of tau in neurons and glia in an irregular, focal, perivascular distribution and at the depths of cortical sulci. Abnormalities of the septum pellucidum, such as cavum and fenestration, are also a common feature.

      While the condition has become increasingly rare due to the progressive improvement in sports safety, it is important to recognize the potential long-term consequences of repeated head injuries and take steps to prevent them.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 191 - What evidence indicates a diagnosis of dementia pugilistica? ...

    Incorrect

    • What evidence indicates a diagnosis of dementia pugilistica?

      Your Answer:

      Correct Answer: A history of recurrent head injury

      Explanation:

      Dementia Pugilistica: A Neurodegenerative Condition Resulting from Neurotrauma

      Dementia pugilistica, also known as chronic traumatic encephalopathy (CTE), is a neurodegenerative condition that results from neurotrauma. It is commonly seen in boxers and NFL players, but can also occur in anyone with neurotrauma. The condition is characterized by symptoms such as gait ataxia, slurred speech, impaired hearing, tremors, disequilibrium, neurobehavioral disturbances, and progressive cognitive decline.

      Most cases of dementia pugilistica present with early onset cognitive deficits, and behavioral signs exhibited by patients include aggression, suspiciousness, paranoia, childishness, hypersexuality, depression, and restlessness. The progression of the condition leads to more prominent behavioral symptoms such as difficulty with impulse control, irritability, inappropriateness, and explosive outbursts of aggression.

      Neuropathological abnormalities have been identified in CTE, with the most unique feature being the abnormal accumulation of tau in neurons and glia in an irregular, focal, perivascular distribution and at the depths of cortical sulci. Abnormalities of the septum pellucidum, such as cavum and fenestration, are also a common feature.

      While the condition has become increasingly rare due to the progressive improvement in sports safety, it is important to recognize the potential long-term consequences of repeated head injuries and take steps to prevent them.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 192 - In which condition is focal slowing observed in the left temporal region on...

    Incorrect

    • In which condition is focal slowing observed in the left temporal region on electroencephalography?

      Your Answer:

      Correct Answer: Normal aging

      Explanation:

      Electroencephalography

      Electroencephalography (EEG) is a clinical test that records the brain’s spontaneous electrical activity over a short period of time using multiple electrodes placed on the scalp. It is mainly used to rule out organic conditions and can help differentiate dementia from other disorders such as metabolic encephalopathies, CJD, herpes encephalitis, and non-convulsive status epilepticus. EEG can also distinguish possible psychotic episodes and acute confusional states from non-convulsive status epilepticus.

      Not all abnormal EEGs represent an underlying condition, and psychotropic medications can affect EEG findings. EEG abnormalities can also be triggered purposely by activation procedures such as hyperventilation, photic stimulation, certain drugs, and sleep deprivation.

      Specific waveforms are seen in an EEG, including delta, theta, alpha, sigma, beta, and gamma waves. Delta waves are found frontally in adults and posteriorly in children during slow wave sleep, and excessive amounts when awake may indicate pathology. Theta waves are generally seen in young children, drowsy and sleeping adults, and during meditation. Alpha waves are seen posteriorly when relaxed and when the eyes are closed, and are also seen in meditation. Sigma waves are bursts of oscillatory activity that occur in stage 2 sleep. Beta waves are seen frontally when busy of concentrating, and gamma waves are seen in advanced/very experienced meditators.

      Certain conditions are associated with specific EEG changes, such as nonspecific slowing in early CJD, low voltage EEG in Huntington’s, diffuse slowing in encephalopathy, and reduced alpha and beta with increased delta and theta in Alzheimer’s.

      Common epileptiform patterns include spikes, spike/sharp waves, and spike-waves. Medications can have important effects on EEG findings, with clozapine decreasing alpha and increasing delta and theta, lithium increasing all waveforms, lamotrigine decreasing all waveforms, and valproate having inconclusive effects on delta and theta and increasing beta.

      Overall, EEG is a useful tool in clinical contexts for ruling out organic conditions and differentiating between various disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 193 - What waveform represents a frequency range of 8-12Hz? ...

    Incorrect

    • What waveform represents a frequency range of 8-12Hz?

      Your Answer:

      Correct Answer: Alpha

      Explanation:

      Electroencephalography

      Electroencephalography (EEG) is a clinical test that records the brain’s spontaneous electrical activity over a short period of time using multiple electrodes placed on the scalp. It is mainly used to rule out organic conditions and can help differentiate dementia from other disorders such as metabolic encephalopathies, CJD, herpes encephalitis, and non-convulsive status epilepticus. EEG can also distinguish possible psychotic episodes and acute confusional states from non-convulsive status epilepticus.

      Not all abnormal EEGs represent an underlying condition, and psychotropic medications can affect EEG findings. EEG abnormalities can also be triggered purposely by activation procedures such as hyperventilation, photic stimulation, certain drugs, and sleep deprivation.

      Specific waveforms are seen in an EEG, including delta, theta, alpha, sigma, beta, and gamma waves. Delta waves are found frontally in adults and posteriorly in children during slow wave sleep, and excessive amounts when awake may indicate pathology. Theta waves are generally seen in young children, drowsy and sleeping adults, and during meditation. Alpha waves are seen posteriorly when relaxed and when the eyes are closed, and are also seen in meditation. Sigma waves are bursts of oscillatory activity that occur in stage 2 sleep. Beta waves are seen frontally when busy of concentrating, and gamma waves are seen in advanced/very experienced meditators.

      Certain conditions are associated with specific EEG changes, such as nonspecific slowing in early CJD, low voltage EEG in Huntington’s, diffuse slowing in encephalopathy, and reduced alpha and beta with increased delta and theta in Alzheimer’s.

      Common epileptiform patterns include spikes, spike/sharp waves, and spike-waves. Medications can have important effects on EEG findings, with clozapine decreasing alpha and increasing delta and theta, lithium increasing all waveforms, lamotrigine decreasing all waveforms, and valproate having inconclusive effects on delta and theta and increasing beta.

      Overall, EEG is a useful tool in clinical contexts for ruling out organic conditions and differentiating between various disorders.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 194 - What is located within Brodmann area 22? ...

    Incorrect

    • What is located within Brodmann area 22?

      Your Answer:

      Correct Answer: Wernicke's area

      Explanation:

      Broca’s and Wernicke’s are two types of expressive dysphasia, which is characterized by difficulty producing speech despite intact comprehension. Dysarthria is a type of expressive dysphasia caused by damage to the speech production apparatus, while Broca’s aphasia is caused by damage to the area of the brain responsible for speech production, specifically Broca’s area located in Brodmann areas 44 and 45. On the other hand, Wernicke’s aphasia is a type of receptive of fluent aphasia caused by damage to the comprehension of speech, while the actual production of speech remains normal. Wernicke’s area is located in the posterior part of the superior temporal gyrus in the dominant hemisphere, within Brodmann area 22.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 195 - Which of the following eosinophilic inclusion bodies are observed as a neuropathological discovery...

    Incorrect

    • Which of the following eosinophilic inclusion bodies are observed as a neuropathological discovery in individuals with Alzheimer's disease?

      Your Answer:

      Correct Answer: Hirano bodies

      Explanation:

      Hirano bodies, Pick bodies, Lewy bodies, Negri bodies, and Barr bodies are all types of inclusion bodies that can be seen in various cells. Hirano bodies are rod-shaped structures found in the cytoplasm of neurons, composed of actin and other proteins. They are commonly seen in the hippocampus, along with granulovacuolar degeneration, which may represent lysosomal accumulations within neuronal cytoplasm. The clinical significance of these microscopic features is not yet fully understood. Pick bodies are masses of cytoskeletal elements seen in Pick’s disease, while Lewy bodies are abnormal protein aggregates that develop in nerve cells in Lewy body disease. Negri bodies are inclusion bodies seen in rabies, and Barr bodies are inactive X chromosomes in a female somatic cell.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 196 - What is a characteristic that is shared by both upper and lower motor...

    Incorrect

    • What is a characteristic that is shared by both upper and lower motor neuron lesions?

      Your Answer:

      Correct Answer: Weakness

      Explanation:

      Motor Neuron Lesions

      Signs of an upper motor neuron lesion include weakness, increased reflexes, increased tone (spasticity), mild atrophy, an upgoing plantar response (Babinski reflex), and clonus. On the other hand, signs of a lower motor neuron lesion include atrophy, weakness, fasciculations, decreased reflexes, and decreased tone. It is important to differentiate between the two types of lesions as they have different underlying causes and require different treatment approaches. A thorough neurological examination can help identify the location and extent of the lesion, which can guide further diagnostic testing and management.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 197 - What is a true statement about the cerebral cortex? ...

    Incorrect

    • What is a true statement about the cerebral cortex?

      Your Answer:

      Correct Answer: The neocortex contains pyramidal cells

      Explanation:

      The cortex is composed of neurons, with the majority being pyramidal neurons that are excitatory and contain glutamate. Grey matter is where neural cell bodies are located, while white matter mainly consists of myelinated axon tracts. The color contrast between the two is due to the white appearance of myelin.

      The Cerebral Cortex and Neocortex

      The cerebral cortex is the outermost layer of the cerebral hemispheres and is composed of three parts: the archicortex, paleocortex, and neocortex. The neocortex accounts for 90% of the cortex and is involved in higher functions such as thought and language. It is divided into 6-7 layers, with two main cell types: pyramidal cells and nonpyramidal cells. The surface of the neocortex is divided into separate areas, each given a number by Brodmann (e.g. Brodmann’s area 17 is the primary visual cortex). The surface is folded to increase surface area, with grooves called sulci and ridges called gyri. The neocortex is responsible for higher cognitive functions and is essential for human consciousness.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 198 - What type of brain tumor is commonly located on the ventricular walls? ...

    Incorrect

    • What type of brain tumor is commonly located on the ventricular walls?

      Your Answer:

      Correct Answer: Ependymoma

      Explanation:

      Cerebral Tumours

      The most common brain tumours in adults, listed in order of frequency, are metastatic tumours, glioblastoma multiforme, anaplastic astrocytoma, and meningioma. On the other hand, the most common brain tumours in children, listed in order of frequency, are astrocytoma, medulloblastoma, and ependymoma.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 199 - Which area of the brain can be damaged to cause expressive dysphasia? ...

    Incorrect

    • Which area of the brain can be damaged to cause expressive dysphasia?

      Your Answer:

      Correct Answer: Frontal lobe

      Explanation:

      Broca’s and Wernicke’s are two types of expressive dysphasia, which is characterized by difficulty producing speech despite intact comprehension. Dysarthria is a type of expressive dysphasia caused by damage to the speech production apparatus, while Broca’s aphasia is caused by damage to the area of the brain responsible for speech production, specifically Broca’s area located in Brodmann areas 44 and 45. On the other hand, Wernicke’s aphasia is a type of receptive of fluent aphasia caused by damage to the comprehension of speech, while the actual production of speech remains normal. Wernicke’s area is located in the posterior part of the superior temporal gyrus in the dominant hemisphere, within Brodmann area 22.

    • This question is part of the following fields:

      • Neurosciences
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  • Question 200 - Which symptom is atypical for individuals with Kluver-Bucy syndrome? ...

    Incorrect

    • Which symptom is atypical for individuals with Kluver-Bucy syndrome?

      Your Answer:

      Correct Answer: Prosopagnosia

      Explanation:

      Kluver-Bucy syndrome is a neurological disorder that results from dysfunction in both the right and left medial temporal lobes of the brain. This condition is characterized by a range of symptoms, including docility, altered dietary habits, hyperorality, and changes in sexual behavior. Additionally, individuals with Kluver-Bucy syndrome may experience visual agnosia, which is a condition that impairs their ability to recognize and interpret visual stimuli.

    • This question is part of the following fields:

      • Neurosciences
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