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Question 1
Incorrect
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What is the causative agent of progressive multifocal leukoencephalopathy (PML), a common opportunistic CNS infection seen in individuals with AIDS?
Your Answer: Cytomegalovirus (CMV)
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.
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This question is part of the following fields:
- Neurosciences
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Question 2
Correct
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Which area of the cerebellum is responsible for regulating precise and delicate movements of the body?
Your Answer: Spinocerebellum
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.
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This question is part of the following fields:
- Neurosciences
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Question 3
Correct
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Which cranial nerve travels through the cribriform plate of the ethmoid bone on its way to the brain?
Your 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.
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This question is part of the following fields:
- Neurosciences
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Question 4
Correct
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What are the consequences of damage to the arcuate fasciculus?
Your 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.
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This question is part of the following fields:
- Neurosciences
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Question 5
Correct
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What is another term for 'intrinsic activity' when referring to drug/receptor interactions?
Your 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.
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This question is part of the following fields:
- Neurosciences
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Question 6
Incorrect
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What EEG waveform corresponds to a frequency range of 12-30Hz?
Your Answer: Alpha
Correct Answer: Beta
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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This question is part of the following fields:
- Neurosciences
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Question 7
Correct
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What is the cause of Balint's syndrome?
Your Answer: Bilateral parieto-occipital lobe dysfunction
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.
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This question is part of the following fields:
- Neurosciences
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Question 8
Incorrect
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What is a true statement about histamine?
Your Answer: H1 receptors are found on the parietal cells of the stomach
Correct Answer: It is metabolised by histamine methyltransferase
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.
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This question is part of the following fields:
- Neurosciences
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Question 9
Incorrect
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What is the most effective method for distinguishing between Alzheimer's disease and Lewy body dementia?
Your Answer:
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.
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This question is part of the following fields:
- Neurosciences
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Question 10
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 11
Incorrect
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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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This question is part of the following fields:
- Neurosciences
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Question 12
Incorrect
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What are the roles of purposes of the amygdala?
Your Answer:
Correct Answer: All of the above
Explanation:The Amygdala: A Key Player in Emotional Processing
The amygdala is a small, almond-shaped structure located in the anterior temporal lobe of the brain. As a core component of the limbic system, it plays a crucial role in emotional processing and regulation.
To better understand its function, we can use the metaphor of a car being driven on the road. The frontal lobe of the brain acts as the driver, making decisions and navigating the environment. The amygdala, on the other hand, serves as the dashboard, providing the driver with important information about the car’s status, such as temperature and fuel levels. In this way, the amygdala gives emotional meaning to sensory input, allowing us to respond appropriately to potential threats of opportunities.
One of the amygdala’s primary functions is to activate the fight or flight response in response to perceived danger. It does this by sending signals to the hypothalamus, which in turn triggers the release of stress hormones like adrenaline and cortisol. This prepares the body to either confront the threat of flee from it.
In addition to its role in the fight or flight response, the amygdala also plays a role in regulating appetite and eating behavior. Studies have shown that damage to the amygdala can lead to overeating and obesity, suggesting that it may be involved in the hypothalamic control of feeding behavior.
Overall, the amygdala is a key player in emotional processing and regulation, helping us to respond appropriately to the world around us.
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This question is part of the following fields:
- Neurosciences
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Question 13
Incorrect
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Which of these is a feature of Balint's syndrome?
Your Answer:
Correct Answer: Simultagnosia
Explanation:Simultagnosia is a condition where an individual is unable to focus on more than one aspect of a complex scene at a time. This condition, along with optic ataxia and oculomotor apraxia, is part of Balint’s syndrome.
Gerstmann syndrome is characterized by four symptoms: dysgraphia/agraphia, dyscalculia/acalculia, finger agnosia, and left-right disorientation. This syndrome is linked to a lesion in the dominant parietal lobe, specifically the left side of the angular and supramarginal gyri. It is rare for an individual to present with all four symptoms of the tetrad.
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This question is part of the following fields:
- Neurosciences
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Question 14
Incorrect
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Which symptom is most commonly associated with occlusion of the anterior cerebral artery?
Your Answer:
Correct Answer: Transcortical motor aphasia
Explanation:Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 15
Incorrect
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In which type of condition of disease are Hirano bodies typically observed?
Your Answer:
Correct Answer: Alzheimer's
Explanation:Hirano bodies are a nonspecific indication of neurodegeneration and are primarily observed in.
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.
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This question is part of the following fields:
- Neurosciences
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Question 16
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 17
Incorrect
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Who received the Nobel prize for their discovery of dopamine's function as a neurotransmitter?
Your Answer:
Correct Answer: Carlsson
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.
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This question is part of the following fields:
- Neurosciences
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Question 18
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 19
Incorrect
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What is a true statement about the endocannabinoid system?
Your Answer:
Correct Answer: CB2 receptors are expressed at much lower levels in the central nervous system compared to CB1
Explanation:The Endocannabinoid System and its Role in Psychosis
The endocannabinoid system (ECS) plays a crucial role in regulating various physiological functions in the body, including cognition, sleep, energy metabolism, and inflammation. It is composed of endogenous cannabinoids, cannabinoid receptors, and proteins that transport, synthesize, and degrade endocannabinoids. The two best-characterized cannabinoid receptors are CB1 and CB2, which primarily couple to inhibitory G proteins and modulate different neurotransmitter systems in the brain.
Impairment of the ECS after cannabis consumption has been linked to an increased risk of psychotic illness. However, enhancing the ECS with cannabidiol (CBD) has shown anti-inflammatory and antipsychotic outcomes in both healthy study participants and in preliminary clinical trials on people with psychotic illness of at high risk of developing psychosis. Studies have also found increased anandamide levels in the cerebrospinal fluid and blood, as well as increased CB1 expression in peripheral immune cells of people with psychotic illness compared to healthy controls. Overall, understanding the role of the ECS in psychosis may lead to new therapeutic approaches for treating this condition.
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This question is part of the following fields:
- Neurosciences
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Question 20
Incorrect
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What waveform represents a frequency range of 4-8 Hz?
Your Answer:
Correct Answer: Theta
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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This question is part of the following fields:
- Neurosciences
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Question 21
Incorrect
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Which of the following is not considered a characteristic of Klüver-Bucy syndrome?
Your Answer:
Correct Answer: Visual apraxia
Explanation: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.
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This question is part of the following fields:
- Neurosciences
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Question 22
Incorrect
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Which symptom is most commonly associated with occlusion of the posterior cerebral artery?
Your Answer:
Correct Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 23
Incorrect
-
What is a true statement about sigma waves in relation to EEG?
Your Answer:
Correct 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.
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This question is part of the following fields:
- Neurosciences
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Question 24
Incorrect
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In which sleep stage are K complexes mostly observed?
Your Answer:
Correct Answer: 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
CommentI
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 erectionDeafness:
(No information provided on deafness in relation to sleep stages)
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This question is part of the following fields:
- Neurosciences
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Question 25
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.
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This question is part of the following fields:
- Neurosciences
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Question 26
Incorrect
-
What is the most likely diagnosis when an MRI shows high signal in the medial aspects of both thalami that is bilateral and symmetrical?
Your Answer:
Correct Answer: Variant CJD
Explanation:The pulvinar sign seen on radiological imaging can indicate several possible conditions, including Alper’s Syndrome, cat-scratch disease, and post-infectious encephalitis. It may also be present in cases of M/V2 subtype of sporadic CJD, thalamic infarctions, and top-of-the-basilar ischemia. However, when considering vCJD, the pulvinar sign should be evaluated in the appropriate clinical context.
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.
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This question is part of the following fields:
- Neurosciences
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Question 27
Incorrect
-
In which hypothalamic nuclei are leptin receptors found in the highest concentration?
Your Answer:
Correct Answer: Arcuate
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.
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This question is part of the following fields:
- Neurosciences
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Question 28
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.
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This question is part of the following fields:
- Neurosciences
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Question 29
Incorrect
-
A middle-aged patient comes to your clinic with a complaint of double vision that they believe is caused by a new medication you prescribed. They report experiencing both vertical and torsional diplopia. During the examination, you observe that they are unable to move their left eye downwards and outwards. Which cranial nerve is most likely affected?
Your Answer:
Correct Answer: IV
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.
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This question is part of the following fields:
- Neurosciences
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Question 30
Incorrect
-
Which component is included in the Papez circuit?
Your Answer:
Correct Answer: Hippocampus
Explanation: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 cingulate 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.
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This question is part of the following fields:
- Neurosciences
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Question 31
Incorrect
-
When activated, which type of receptor increases the permeability of a plasma membrane to chloride ions?
Your Answer:
Correct Answer: GABA-A
Explanation:GABA-A is the sole ionotropic receptor among the options provided. Its function involves the selective conduction of chloride ions across the cell membrane upon activation by GABA, leading to hyperpolarization of the neuron.
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.
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This question is part of the following fields:
- Neurosciences
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Question 32
Incorrect
-
By which process is dopamine broken down?
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.
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This question is part of the following fields:
- Neurosciences
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Question 33
Incorrect
-
Which of the following is another term for a neuropathic gait?
Your Answer:
Correct Answer: Equine gait
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.
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This question is part of the following fields:
- Neurosciences
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Question 34
Incorrect
-
Which of the following is not a component of the syndrome of frontotemporal lobe degeneration (FTLD)?
Your Answer:
Correct Answer: Posterior cortical atrophy
Explanation:Frontotemporal lobe degeneration (FTLD) encompasses various syndromes, such as Pick’s disease, primary progressive aphasia (which impacts speech), semantic dementia (affecting conceptual knowledge), and corticobasal degeneration (characterized by asymmetrical akinetic-rigid syndrome and apraxia). It is important to note that posterior cortical atrophy, which involves tissue loss in the posterior regions and affects higher visual processing, is not considered a part of the FTLD syndrome.
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This question is part of the following fields:
- Neurosciences
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Question 35
Incorrect
-
What is a true statement about the cingulate gyrus?
Your Answer:
Correct Answer: It is involved in reward-based decision making
Explanation:The fusiform gyrus is essential for recognizing faces and bodies, while damage to the angular gyrus can result in Gerstmann syndrome.
The Cingulate Gyrus: A Hub for Emotions and Decision Making
The cingulate gyrus is a cortical fold located on the medial aspect of the cerebral hemisphere, adjacent to the corpus callosum. As part of the limbic system, it plays a crucial role in processing emotions and regulating the body’s endocrine and autonomic responses to emotional stimuli. Additionally, it is involved in reward-based decision making. Essentially, the cingulate gyrus acts as a hub that connects emotions, sensations, and actions. The term cingulate comes from the Latin word for belt of girdle, which reflects the way in which it wraps around the corpus callosum.
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This question is part of the following fields:
- Neurosciences
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Question 36
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.
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This question is part of the following fields:
- Neurosciences
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Question 37
Incorrect
-
Which receptor's agonist effect is most likely responsible for anorgasmia caused by SSRIs?
Your Answer:
Correct Answer: 5HT2C
Explanation:As an AI language model, I cannot provide a response without knowing the context of the rewrite you are referring to. Please provide more information of context so that I can assist you better.
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).
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This question is part of the following fields:
- Neurosciences
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Question 38
Incorrect
-
Which sensory component is correctly matched with its corresponding cranial nerve reflex?
Your Answer:
Correct Answer: Gag reflex - IX cranial nerve
Explanation:The question specifically requests the sensory aspect.
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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This question is part of the following fields:
- Neurosciences
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Question 39
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.
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This question is part of the following fields:
- Neurosciences
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Question 40
Incorrect
-
Which feature is not very useful in distinguishing between Parkinson's disease and progressive supranuclear palsy?
Your Answer:
Correct Answer: Pallor of the substantia nigra
Explanation:Both conditions exhibit pallor of the substantia nigra. However, in PSP, the locus coeruleus is typically unaffected, whereas in Parkinson’s disease, it shows pallor. Therefore, if there is pallor in this area, it would indicate Parkinson’s disease.
Pathology of Progressive Supranuclear Palsy
Progressive supranuclear palsy is a rare disorder that affects gait and balance, often accompanied by changes in mood, behavior, and dementia. The macroscopic changes observed in this condition include pallor of the substantia nigra (with sparing of the locus coeruleus), mild midbrain atrophy, atrophy of the superior cerebellar peduncles, and discolouration of the dentate nucleus. On a microscopic level, gliosis and the presence of neurofibrillary tangles and tau inclusions in both astrocytes and oligodendrocytes (coiled bodies) are observed, particularly in the substantia nigra, subthalamic nucleus, and globus pallidus.
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This question is part of the following fields:
- Neurosciences
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Question 41
Incorrect
-
Which of the following conditions is not associated with a distinct EEG pattern?
Your Answer:
Correct Answer: Variant CJD
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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This question is part of the following fields:
- Neurosciences
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Question 42
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.
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This question is part of the following fields:
- Neurosciences
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Question 43
Incorrect
-
Which statement about the anatomy of the basal ganglia is accurate?
Your Answer:
Correct Answer: The subthalamic nucleus is part of the basal ganglia
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.
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This question is part of the following fields:
- Neurosciences
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Question 44
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.
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This question is part of the following fields:
- Neurosciences
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Question 45
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.
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This question is part of the following fields:
- Neurosciences
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Question 46
Incorrect
-
What area of the brain is affected in bilateral dysfunction that leads to Klüver-Bucy syndrome?
Your Answer:
Correct Answer: Amygdala
Explanation: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.
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This question is part of the following fields:
- Neurosciences
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Question 47
Incorrect
-
What is the condition that occurs due to the deterioration of the caudate nucleus?
Your Answer:
Correct Answer: Huntington's
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.
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This question is part of the following fields:
- Neurosciences
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Question 48
Incorrect
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At what threshold does the membrane potential of a cell need to reach in order to trigger an action potential?
Your Answer:
Correct Answer: -55 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.
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This question is part of the following fields:
- Neurosciences
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Question 49
Incorrect
-
Which cranial nerve is solely responsible for either sensory of motor functions and does not have a combination of both?
Your Answer:
Correct Answer: Abducens
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.
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This question is part of the following fields:
- Neurosciences
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Question 50
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.
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This question is part of the following fields:
- Neurosciences
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Question 51
Incorrect
-
Which of the following diseases is not considered a prion disease?
Your Answer:
Correct Answer: Dhat
Explanation:Dhat is a syndrome that is specific to Indian culture and affects men. Those who suffer from it experience anxiety about the presence of semen in their urine, which they believe leads to a loss of energy.
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.
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This question is part of the following fields:
- Neurosciences
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Question 52
Incorrect
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Can you identify the neurotransmitter that is often studied and also referred to as prolactin-inhibiting factor (PIF)?
Your Answer:
Correct Answer: Dopamine
Explanation:Prolactin secretion from the anterior pituitary gland is inhibited by dopamine, which is also referred to as prolactin-inhibiting factor (PIF) and prolactin-inhibiting hormone (PIH). The reason why antipsychotic medications are linked to hyperprolactinaemia is due to the antagonism of dopamine receptors. On the other hand, serotonin and melatonin seem to stimulate prolactin secretion. While animal studies have indicated that adrenaline and noradrenaline can decrease prolactin secretion, their effect is not as significant as that of dopamine.
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This question is part of the following fields:
- Neurosciences
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Question 53
Incorrect
-
What is the accurate statement about the pathology of Parkinson's disease?
Your Answer:
Correct Answer: Pallor of the locus coeruleus is seen
Explanation:Lewy bodies are not exclusively indicative of a particular disease, as they can also be present in individuals with Alzheimer’s and even in those who do not exhibit any noticeable symptoms.
Parkinson’s Disease Pathology
Parkinson’s disease is a neurodegenerative disorder that affects the central nervous system. The pathology of Parkinson’s disease is very similar to that of Lewy body dementia. The macroscopic features of Parkinson’s disease include pallor of the substantia nigra (midbrain) and locus coeruleus (pons). The microscopic changes include the presence of Lewy bodies, which are intracellular aggregates of alpha-synuclein. Additionally, there is a loss of dopaminergic cells from the substantia nigra pars compacta. These changes contribute to the motor symptoms of Parkinson’s disease, such as tremors, rigidity, and bradykinesia. Understanding the pathology of Parkinson’s disease is crucial for developing effective treatments and improving the quality of life for those affected by this condition.
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This question is part of the following fields:
- Neurosciences
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Question 54
Incorrect
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Where are Lewy bodies commonly located within the basal ganglia in individuals with Parkinson's disease?
Your Answer:
Correct Answer: The pars compacta
Explanation:The midbrain contains a section called the pars compacta, which is made up of neurons that produce dopamine and is situated next to the pars reticulata. Parkinson’s disease is identified by the loss of these dopamine-producing neurons in this area.
Parkinson’s Disease Pathology
Parkinson’s disease is a neurodegenerative disorder that affects the central nervous system. The pathology of Parkinson’s disease is very similar to that of Lewy body dementia. The macroscopic features of Parkinson’s disease include pallor of the substantia nigra (midbrain) and locus coeruleus (pons). The microscopic changes include the presence of Lewy bodies, which are intracellular aggregates of alpha-synuclein. Additionally, there is a loss of dopaminergic cells from the substantia nigra pars compacta. These changes contribute to the motor symptoms of Parkinson’s disease, such as tremors, rigidity, and bradykinesia. Understanding the pathology of Parkinson’s disease is crucial for developing effective treatments and improving the quality of life for those affected by this condition.
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This question is part of the following fields:
- Neurosciences
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Question 55
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.
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This question is part of the following fields:
- Neurosciences
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Question 56
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.
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This question is part of the following fields:
- Neurosciences
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Question 57
Incorrect
-
What is the most consistently observed pathology in schizophrenia?
Your Answer:
Correct Answer: Reduced total grey matter volume
Explanation:Alzheimer’s disease is associated with the presence of Hirano bodies.
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.
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This question is part of the following fields:
- Neurosciences
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Question 58
Incorrect
-
Which of the following conditions is characterized by an increase in the size of the ventricles on structural neuroimaging over time?
Your Answer:
Correct Answer: Alzheimer's dementia
Explanation:Neuroimaging studies have shown that Alzheimer’s dementia is linked to a gradual increase in ventricular size, while schizophrenia is associated with non-progressive enlargement of the lateral and third ventricles. Although some studies have reported increased ventricular size in individuals with affective disorders, the findings are not consistent. Additionally, individuals with antisocial personality disorder may have reduced prefrontal gray matter volume.
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This question is part of the following fields:
- Neurosciences
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Question 59
Incorrect
-
What is the embryonic structure that gives rise to the cerebellum and pons?
Your Answer:
Correct Answer: Metencephalon
Explanation:During fetal development, the neural tube at the cranial end gives rise to three major parts: the prosencephalon, mesencephalon, and rhombencephalon. The prosencephalon further divides into the telencephalon and diencephalon, forming the forebrain. The mesencephalon forms the midbrain, while the rhombencephalon splits into the metencephalon (which gives rise to the cerebellum and pons) and myelencephalon (which forms the medulla oblongata and spinal cord).
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This question is part of the following fields:
- Neurosciences
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Question 60
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.
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This question is part of the following fields:
- Neurosciences
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Question 61
Incorrect
-
What is the precursor amino acid for dopamine synthesis?
Your Answer:
Correct Answer: Tyrosine
Explanation:Tyrosine is converted to L-DOPA by the enzyme tyrosine hydroxylase. L-DOPA is then converted to dopamine by the enzyme dopa decarboxylase.
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.
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This question is part of the following fields:
- Neurosciences
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Question 62
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.
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This question is part of the following fields:
- Neurosciences
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Question 63
Incorrect
-
Which area of the brain is responsible for causing hemiballismus when it is damaged?
Your Answer:
Correct Answer: Subthalamic nucleus
Explanation:Hemiballismus is an uncommon condition that arises following a stroke affecting the basal ganglia, particularly the subthalamic nucleus. It is typically identified by uncontrolled flinging movements of the limbs, which can be forceful and have a broad range of motion. These movements are unpredictable and ongoing, and may affect either the proximal or distal muscles on one side of the body.
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.
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This question is part of the following fields:
- Neurosciences
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Question 64
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
CommentI
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 erectionDeafness:
(No information provided on deafness in relation to sleep stages)
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This question is part of the following fields:
- Neurosciences
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Question 65
Incorrect
-
In what conditions are Kuru plaques occasionally observed?
Your Answer:
Correct Answer: Creutzfeldt-Jakob disease
Explanation:Pathology Findings in Psychiatry
There are several pathology findings that are associated with various psychiatric conditions. Papp-Lantos bodies, for example, are visible in the CNS and are associated with multisystem atrophy. Pick bodies, on the other hand, are large, dark-staining aggregates of proteins in neurological tissue and are associated with frontotemporal dementia.
Lewy bodies are another common pathology finding in psychiatry and are associated with Parkinson’s disease and Lewy Body dementia. These are round, concentrically laminated, pale eosinophilic cytoplasmic inclusions that are aggregates of alpha-synuclein.
Other pathology findings include asteroid bodies, which are associated with sarcoidosis and berylliosis, and are acidophilic, stellate inclusions in giant cells. Barr bodies are associated with stains of X chromosomes and are inactivated X chromosomes that appear as a dark staining mass in contact with the nuclear membrane.
Mallory bodies are another common pathology finding and are associated with alcoholic hepatitis, alcoholic cirrhosis, Wilson’s disease, and primary-biliary cirrhosis. These are eosinophilic intracytoplasmic inclusions in hepatocytes that are made up of intermediate filaments, predominantly prekeratin.
Other pathology findings include Schaumann bodies, which are associated with sarcoidosis and berylliosis, and are concentrically laminated inclusions in giant cells. Zebra bodies are associated with Niemann-Pick disease, Tay-Sachs disease, of any of the mucopolysaccharidoses and are palisaded lamellated membranous cytoplasmic bodies seen in macrophages.
LE bodies, also known as hematoxylin bodies, are associated with SLE (lupus) and are nuclei of damaged cells with bound anti-nuclear antibodies that become homogeneous and loose chromatin pattern. Verocay bodies are associated with Schwannoma (Neurilemoma) and are palisades of nuclei at the end of a fibrillar bundle.
Hirano bodies are associated with normal aging but are more numerous in Alzheimer’s disease. These are eosinophilic, football-shaped inclusions seen in neurons of the brain. Neurofibrillary tangles are another common pathology finding in Alzheimer’s disease and are made up of microtubule-associated proteins and neurofilaments.
Kayser-Fleischer rings are associated with Wilson’s disease and are rings of discoloration on the cornea. Finally, Kuru plaques are associated with Kuru and Gerstmann-Sträussler syndrome and are sometimes present in patients with Creutzfeldt-Jakob disease (CJD). These are composed partly of a host-encoded prion protein.
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This question is part of the following fields:
- Neurosciences
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Question 66
Incorrect
-
What is the most effective tool to use when suspecting a brain hemorrhage in an emergency situation?
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.
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This question is part of the following fields:
- Neurosciences
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Question 67
Incorrect
-
Which condition is most commonly associated with fast, generalized spike and wave activity on the EEG?
Your Answer:
Correct Answer: Myoclonic epilepsy
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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This question is part of the following fields:
- Neurosciences
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Question 68
Incorrect
-
What is the most probable outcome of the occlusion of the main trunk of the middle cerebral artery?
Your Answer:
Correct Answer: Hemiparesis of the contralateral face and limbs
Explanation:Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 69
Incorrect
-
What is the main structural component of alpha-synuclein?
Your Answer:
Correct Answer: Lewy bodies
Explanation:Parkinson’s Disease Pathology
Parkinson’s disease is a neurodegenerative disorder that affects the central nervous system. The pathology of Parkinson’s disease is very similar to that of Lewy body dementia. The macroscopic features of Parkinson’s disease include pallor of the substantia nigra (midbrain) and locus coeruleus (pons). The microscopic changes include the presence of Lewy bodies, which are intracellular aggregates of alpha-synuclein. Additionally, there is a loss of dopaminergic cells from the substantia nigra pars compacta. These changes contribute to the motor symptoms of Parkinson’s disease, such as tremors, rigidity, and bradykinesia. Understanding the pathology of Parkinson’s disease is crucial for developing effective treatments and improving the quality of life for those affected by this condition.
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This question is part of the following fields:
- Neurosciences
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Question 70
Incorrect
-
What is the main component of pick bodies?
Your Answer:
Correct Answer: Tau
Explanation:Pyramidal cell neurons known as Betz cells are situated in the grey matter of the motor cortex.
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.
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This question is part of the following fields:
- Neurosciences
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Question 71
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.
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This question is part of the following fields:
- Neurosciences
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Question 72
Incorrect
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What is a true statement about Broca's aphasia?
Your Answer:
Correct Answer: Main areas affected are Brodmann areas 44 and 45
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.
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This question is part of the following fields:
- Neurosciences
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Question 73
Incorrect
-
A 40 year old female is admitted to the ward with a diagnosis of depression. On admission the doctor notes skin changes consistent with erythema nodosum and also notes that the patient complains of being short of breath. Unfortunately the lady commits suicide shortly after admission. A post-mortem biopsy reveals Asteroid bodies. Which of the following diagnosis would you most suspect?:
Your Answer:
Correct Answer: Sarcoidosis
Explanation:Pathology Findings in Psychiatry
There are several pathology findings that are associated with various psychiatric conditions. Papp-Lantos bodies, for example, are visible in the CNS and are associated with multisystem atrophy. Pick bodies, on the other hand, are large, dark-staining aggregates of proteins in neurological tissue and are associated with frontotemporal dementia.
Lewy bodies are another common pathology finding in psychiatry and are associated with Parkinson’s disease and Lewy Body dementia. These are round, concentrically laminated, pale eosinophilic cytoplasmic inclusions that are aggregates of alpha-synuclein.
Other pathology findings include asteroid bodies, which are associated with sarcoidosis and berylliosis, and are acidophilic, stellate inclusions in giant cells. Barr bodies are associated with stains of X chromosomes and are inactivated X chromosomes that appear as a dark staining mass in contact with the nuclear membrane.
Mallory bodies are another common pathology finding and are associated with alcoholic hepatitis, alcoholic cirrhosis, Wilson’s disease, and primary-biliary cirrhosis. These are eosinophilic intracytoplasmic inclusions in hepatocytes that are made up of intermediate filaments, predominantly prekeratin.
Other pathology findings include Schaumann bodies, which are associated with sarcoidosis and berylliosis, and are concentrically laminated inclusions in giant cells. Zebra bodies are associated with Niemann-Pick disease, Tay-Sachs disease, of any of the mucopolysaccharidoses and are palisaded lamellated membranous cytoplasmic bodies seen in macrophages.
LE bodies, also known as hematoxylin bodies, are associated with SLE (lupus) and are nuclei of damaged cells with bound anti-nuclear antibodies that become homogeneous and loose chromatin pattern. Verocay bodies are associated with Schwannoma (Neurilemoma) and are palisades of nuclei at the end of a fibrillar bundle.
Hirano bodies are associated with normal aging but are more numerous in Alzheimer’s disease. These are eosinophilic, football-shaped inclusions seen in neurons of the brain. Neurofibrillary tangles are another common pathology finding in Alzheimer’s disease and are made up of microtubule-associated proteins and neurofilaments.
Kayser-Fleischer rings are associated with Wilson’s disease and are rings of discoloration on the cornea. Finally, Kuru plaques are associated with Kuru and Gerstmann-Sträussler syndrome and are sometimes present in patients with Creutzfeldt-Jakob disease (CJD). These are composed partly of a host-encoded prion protein.
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This question is part of the following fields:
- Neurosciences
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Question 74
Incorrect
-
What pathological finding is indicative of multisystem atrophy?
Your Answer:
Correct Answer: Shrinkage of the putamen
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.
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This question is part of the following fields:
- Neurosciences
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Question 75
Incorrect
-
In the basal ganglia, what structures make up the lenticular nucleus, including the globus pallidus and which other component?
Your Answer:
Correct Answer: Putamen
Explanation:Located in the epithalamus at the center of the brain, the pineal gland is an endocrine gland. The basal ganglia, also known as basal nuclei, consist of four primary components: the caudate, nucleus accumbens, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. The lenticular (of lentiform) nucleus is formed by the globus pallidus and putamen.
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This question is part of the following fields:
- Neurosciences
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Question 76
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.
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This question is part of the following fields:
- Neurosciences
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Question 77
Incorrect
-
Which serotonin receptor is associated with regulating circadian rhythms?
Your Answer:
Correct Answer: 5HT-7
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).
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This question is part of the following fields:
- Neurosciences
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Question 78
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.
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This question is part of the following fields:
- Neurosciences
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Question 79
Incorrect
-
What structure has been found to exhibit excessive activity in individuals with depression?
Your Answer:
Correct Answer: Amygdala
Explanation:Neuroimaging and Depression
Research on depression using neuroimaging has revealed several important findings. One such finding is that the volume of the amygdala decreases with an increasing number of depressive episodes. Additionally, studies using positron emission tomography (PET) have shown that individuals with depression have elevated baseline amygdala activity that is positively correlated with the severity of their depression. Furthermore, depressed individuals exhibit greater amygdala reactivity to negative emotional stimuli compared to healthy controls.
Another area of interest is the subgenual anterior cingulate cortex (ACC), where increased levels of activity have been observed in depressed individuals. Several studies have also reported decreased volume in the subgenual ACC associated with depression. Finally, researchers have found that depressed individuals exhibit less reactivity in the dorsolateral prefrontal cortex (DLPFC) to affective stimuli compared to healthy controls.
In summary, neuroimaging research suggests that the amygdala and subgenual ACC are overactive in depression, while the DLPFC is underactive. These findings provide important insights into the neural mechanisms underlying depression and may inform the development of more effective treatments.
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This question is part of the following fields:
- Neurosciences
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Question 80
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 rightNon-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 81
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 82
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 83
Incorrect
-
How would you describe Broca's aphasia in a speech?
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.
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This question is part of the following fields:
- Neurosciences
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Question 84
Incorrect
-
What neuropathological evidence would provide the strongest support for a diagnosis of chronic traumatic encephalopathy?
Your Answer:
Correct Answer: Tau accumulations, predominantly around small intracortical blood vessels
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.
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This question is part of the following fields:
- Neurosciences
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Question 85
Incorrect
-
What neurotransmitter is recognized for its significant role in triggering hunger?
Your Answer:
Correct Answer: Orexin
Explanation:Neurotransmitters and their functions:
Orexin, which is derived from the Greek word for ‘appetite’, is responsible for regulating arousal, wakefulness, and appetite. It is also known as hypocretin and is produced in the hypothalamus. Orexin increases the craving for food.
Glutamate is an excitatory amino acid that plays a crucial role in the nervous system. It is responsible for transmitting signals between nerve cells and is involved in learning and memory.
Prolactin is a neurotransmitter produced by the hypothalamus. It is also known as ‘dopamine inhibitory factor’ and is important in the regulation of sexual function. Prolactin levels increase during pregnancy and breastfeeding.
Serotonin is a monoamine neurotransmitter that has a range of actions, including decreasing appetite. It is involved in regulating mood, sleep, and appetite. Low levels of serotonin have been linked to depression and anxiety.
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This question is part of the following fields:
- Neurosciences
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Question 86
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 87
Incorrect
-
What statement accurately describes the trigeminal nerve?
Your Answer:
Correct Answer: It is a mixed nerve with both sensory and motor functions
Explanation:The trigeminal nerve, which is the largest cranial nerve, serves both sensory and motor functions. It is composed of three primary branches, namely the ophthalmic, maxillary, and mandibular branches. This nerve is responsible for providing sensory information to the face and head, while also controlling the muscles involved in chewing. On the other hand, the facial nerve is responsible for controlling the muscles that enable facial expressions and transmitting information from the front two-thirds of the tongue.
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.
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This question is part of the following fields:
- Neurosciences
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Question 88
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.
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This question is part of the following fields:
- Neurosciences
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Question 89
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.
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This question is part of the following fields:
- Neurosciences
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Question 90
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.
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This question is part of the following fields:
- Neurosciences
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Question 91
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 92
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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Question 93
Incorrect
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What type of dysarthria is typically caused by damage to the lower motor neurons related to a tumor?
Your Answer:
Correct Answer: Flaccid 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.
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This question is part of the following fields:
- Neurosciences
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Question 94
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.
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This question is part of the following fields:
- Neurosciences
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Question 95
Incorrect
-
Which artery is likely to be affected if a patient is unable to read but can still write after experiencing a stroke?
Your Answer:
Correct Answer: Left posterior cerebral
Explanation:An infarction to the left posterior cerebral artery typically results in pure alexia, also known as alexia without agraphia, which is characterized by the inability to read but the ability to write.
Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 96
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
CommentI
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 erectionDeafness:
(No information provided on deafness in relation to sleep stages)
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This question is part of the following fields:
- Neurosciences
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Question 97
Incorrect
-
A woman comes to the clinic with a sudden loss of vision in both eyes. There are no abnormalities in the front part of the eye of the back part of the eye, and her pupils react normally to light. What is the most probable location of the blockage in the artery?
Your Answer:
Correct Answer: Posterior cerebral arteries
Explanation:Bilateral infarction in the territory supplied by the distal posterior cerebral arteries can lead to cortical blindness with preserved pupillary reflex. This condition is often accompanied by Anton’s syndrome, where patients are unaware of their blindness.
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This question is part of the following fields:
- Neurosciences
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Question 98
Incorrect
-
In what type of epilepsy is it most common to experience an aura?
Your Answer:
Correct Answer: Temporal lobe
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.
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This question is part of the following fields:
- Neurosciences
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Question 99
Incorrect
-
Where do macroscopic abnormalities typically appear in the brains of individuals with dyslexia?
Your Answer:
Correct Answer: Planum temporale
Explanation:Brain Abnormalities in Dyslexia
Individuals with dyslexia often exhibit a loss of the typical left-right asymmetry at the planum temporale in the temporal lobe. However, this abnormality can also be observed in the brains of individuals without dyslexia, making it a sensitive but not specific marker for the disorder. None of the other brain regions mentioned are associated with dyslexia. The pineal gland, located in the epithalamus, secretes melatonin. The third interstitial nucleus of the anterior hypothalamus is larger in heterosexual men compared to homosexual men and heterosexual women. The medulla oblongata is located in the brainstem, and the lateral geniculate nucleus in the thalamus relays visual information from the retina to the occipital cortex.
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This question is part of the following fields:
- Neurosciences
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Question 100
Incorrect
-
From which amino acid is noradrenaline (norepinephrine) 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.
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This question is part of the following fields:
- Neurosciences
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Question 101
Incorrect
-
Which of the following binds to metabotropic receptors but not ionotropic receptors?
Your Answer:
Correct Answer: Dopaminergic
Explanation:Dopamine receptors are classified as metabotropic receptors rather than ionotropic receptors.
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.
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This question is part of the following fields:
- Neurosciences
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Question 102
Incorrect
-
A 3-year-old girl wakes up crying in the middle of the night. This typically occurs shortly after she has fallen asleep. Her parents report that she sits up in bed and appears to be awake but does not acknowledge them. The episodes last for a few minutes before the child falls back asleep. The parents have checked her pulse during these episodes and note that it is very rapid. This started happening around six months ago and lasted for about two weeks before resolving on its own. What is the likely diagnosis?
Your Answer:
Correct Answer: Night terrors
Explanation:Night terrors are a type of sleep disorder that typically occur during the first few hours of sleep. They are characterized by sudden and intense feelings of fear, panic, of terror that can cause the person to scream, thrash around, of even try to escape from their bed. Unlike nightmares, which occur during REM sleep and are often remembered upon waking, night terrors occur during non-REM sleep and are usually not remembered. Night terrors are most common in children, but can also occur in adults. They are thought to be caused by a combination of genetic and environmental factors, and may be triggered by stress, anxiety, of sleep deprivation. Treatment for night terrors may include improving sleep hygiene, reducing stress, and in some cases, medication.
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This question is part of the following fields:
- Neurosciences
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Question 103
Incorrect
-
Which of the following is an exocannabinoid?
Your Answer:
Correct Answer: Delta-9-tetrahydrocannabinol
Explanation:The Endocannabinoid System and its Role in Psychosis
The endocannabinoid system (ECS) plays a crucial role in regulating various physiological functions in the body, including cognition, sleep, energy metabolism, and inflammation. It is composed of endogenous cannabinoids, cannabinoid receptors, and proteins that transport, synthesize, and degrade endocannabinoids. The two best-characterized cannabinoid receptors are CB1 and CB2, which primarily couple to inhibitory G proteins and modulate different neurotransmitter systems in the brain.
Impairment of the ECS after cannabis consumption has been linked to an increased risk of psychotic illness. However, enhancing the ECS with cannabidiol (CBD) has shown anti-inflammatory and antipsychotic outcomes in both healthy study participants and in preliminary clinical trials on people with psychotic illness of at high risk of developing psychosis. Studies have also found increased anandamide levels in the cerebrospinal fluid and blood, as well as increased CB1 expression in peripheral immune cells of people with psychotic illness compared to healthy controls. Overall, understanding the role of the ECS in psychosis may lead to new therapeutic approaches for treating this condition.
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This question is part of the following fields:
- Neurosciences
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Question 104
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.
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This question is part of the following fields:
- Neurosciences
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Question 105
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.
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This question is part of the following fields:
- Neurosciences
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Question 106
Incorrect
-
Which condition can be diagnosed based on an atypical tonsillar biopsy result?
Your Answer:
Correct Answer: Variant CJD
Explanation:To confirm a diagnosis of variant CJD, a tonsillar biopsy is performed as it is the only form of CJD that impacts the lymph nodes.
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.
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This question is part of the following fields:
- Neurosciences
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Question 107
Incorrect
-
Which process breaks down dopamine?
Your Answer:
Correct Answer: COMT and both forms of MAO
Explanation:COMT and both types of MAO are responsible for the metabolism of dopamine.
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.
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This question is part of the following fields:
- Neurosciences
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Question 108
Incorrect
-
Which receptor functions as an ionotropic receptor?
Your Answer:
Correct Answer: 5HT-3
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.
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This question is part of the following fields:
- Neurosciences
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Question 109
Incorrect
-
Where is serotonin primarily produced in the body?
Your Answer:
Correct Answer: Raphe nuclei
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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This question is part of the following fields:
- Neurosciences
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Question 110
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.
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This question is part of the following fields:
- Neurosciences
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Question 111
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.
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This question is part of the following fields:
- Neurosciences
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Question 112
Incorrect
-
What is a true statement about Lewy bodies?
Your Answer:
Correct Answer: Cortical Lewy bodies typically lack a halo on staining
Explanation:The absence of a halo distinguishes the Lewy bodies found in the brainstem from those found in the cortex. These bodies consist of alpha-synuclein protein, along with other proteins like ubiquitin, neurofilament protein, and alpha B crystallin. Additionally, they may contain tau proteins and are sometimes encircled by neurofibrillary tangles.
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.
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This question is part of the following fields:
- Neurosciences
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Question 113
Incorrect
-
From which substance is melatonin produced?
Your Answer:
Correct Answer: Serotonin
Explanation:Melatonin: The Hormone of Darkness
Melatonin is a hormone that is produced in the pineal gland from serotonin. This hormone is known to be released in higher amounts during the night, especially in dark environments. Melatonin plays a crucial role in regulating the sleep-wake cycle and is often referred to as the hormone of darkness.
The production of melatonin is influenced by the amount of light that enters the eyes. When it is dark, the pineal gland releases more melatonin, which helps to promote sleep. On the other hand, when it is light, the production of melatonin is suppressed, which helps to keep us awake and alert.
Melatonin is also known to have antioxidant properties and may help to protect the body against oxidative stress. It has been suggested that melatonin may have a role in the prevention of certain diseases, such as cancer and neurodegenerative disorders.
Overall, melatonin is an important hormone that plays a crucial role in regulating our sleep-wake cycle and may have other health benefits as well.
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This question is part of the following fields:
- Neurosciences
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Question 114
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.
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This question is part of the following fields:
- Neurosciences
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Question 115
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.
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This question is part of the following fields:
- Neurosciences
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Question 116
Incorrect
-
What is the primary neurotransmitter responsible for excitatory signals in the brain?
Your Answer:
Correct Answer: Glutamate
Explanation:Glutamate is the primary neurotransmitter responsible for excitatory signaling in the brain.
Glutamate: The Most Abundant Neurotransmitter in the Brain
Glutamate is a neurotransmitter that is found in abundance in the brain. It is always excitatory and can act through both ionotropic and metabotropic receptors. This neurotransmitter is believed to play a crucial role in learning and memory processes. Its ability to stimulate neurons and enhance synaptic plasticity is thought to be responsible for its role in memory formation. Glutamate is also involved in various other brain functions, including motor control, sensory perception, and emotional regulation. Its importance in the brain makes it a target for various neurological disorders, including Alzheimer’s disease, Parkinson’s disease, and epilepsy.
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This question is part of the following fields:
- Neurosciences
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Question 117
Incorrect
-
An older woman presents to the emergency department with sudden onset of left leg dysfunction, urinary incontinence, and abulia. As her time in the department progresses, her left arm also becomes affected. She has a history of vascular disease. Which artery do you suspect is involved?
Your Answer:
Correct Answer: Anterior cerebral artery
Explanation:When there is a blockage in the anterior cerebral artery, the legs are typically impacted more than the arms. Additionally, a common symptom is abulia, which is a lack of determination of difficulty making firm decisions.
Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 118
Incorrect
-
What are the eosinophilic inclusion bodies observed in Alzheimer's Disease?
Your Answer:
Correct Answer: Hirano bodies
Explanation:Pathology Findings in Psychiatry
There are several pathology findings that are associated with various psychiatric conditions. Papp-Lantos bodies, for example, are visible in the CNS and are associated with multisystem atrophy. Pick bodies, on the other hand, are large, dark-staining aggregates of proteins in neurological tissue and are associated with frontotemporal dementia.
Lewy bodies are another common pathology finding in psychiatry and are associated with Parkinson’s disease and Lewy Body dementia. These are round, concentrically laminated, pale eosinophilic cytoplasmic inclusions that are aggregates of alpha-synuclein.
Other pathology findings include asteroid bodies, which are associated with sarcoidosis and berylliosis, and are acidophilic, stellate inclusions in giant cells. Barr bodies are associated with stains of X chromosomes and are inactivated X chromosomes that appear as a dark staining mass in contact with the nuclear membrane.
Mallory bodies are another common pathology finding and are associated with alcoholic hepatitis, alcoholic cirrhosis, Wilson’s disease, and primary-biliary cirrhosis. These are eosinophilic intracytoplasmic inclusions in hepatocytes that are made up of intermediate filaments, predominantly prekeratin.
Other pathology findings include Schaumann bodies, which are associated with sarcoidosis and berylliosis, and are concentrically laminated inclusions in giant cells. Zebra bodies are associated with Niemann-Pick disease, Tay-Sachs disease, of any of the mucopolysaccharidoses and are palisaded lamellated membranous cytoplasmic bodies seen in macrophages.
LE bodies, also known as hematoxylin bodies, are associated with SLE (lupus) and are nuclei of damaged cells with bound anti-nuclear antibodies that become homogeneous and loose chromatin pattern. Verocay bodies are associated with Schwannoma (Neurilemoma) and are palisades of nuclei at the end of a fibrillar bundle.
Hirano bodies are associated with normal aging but are more numerous in Alzheimer’s disease. These are eosinophilic, football-shaped inclusions seen in neurons of the brain. Neurofibrillary tangles are another common pathology finding in Alzheimer’s disease and are made up of microtubule-associated proteins and neurofilaments.
Kayser-Fleischer rings are associated with Wilson’s disease and are rings of discoloration on the cornea. Finally, Kuru plaques are associated with Kuru and Gerstmann-Sträussler syndrome and are sometimes present in patients with Creutzfeldt-Jakob disease (CJD). These are composed partly of a host-encoded prion protein.
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This question is part of the following fields:
- Neurosciences
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Question 119
Incorrect
-
A 62-year-old woman is referred to your clinic.
Her daughter has noticed a progressive behavioural change in her mother. She is more aggressive whilst demanding attention. She giggles uncontrollably for no apparent reason, and has been seen wandering outside their house without proper clothing. She has also become more forgetful over the last six months.
She is physically well and has no problems with her heart, blood pressure of diabetes. She is on no medication. You conduct cognitive testing and refer the woman for an EEG.
What is the most probable EEG finding?Your Answer:
Correct Answer: Normal EEG
Explanation:The individual’s age, behavioral changes, disinhibition, and fatuous giggling suggest a diagnosis of frontal lobe dementia, which is further supported by their physical examination. The absence of focal abnormalities on EEG rules out the possibility of vascular dementia. Typically, EEG results are normal during the early stages of this condition and remain so until the advanced stages.
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This question is part of the following fields:
- Neurosciences
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Question 120
Incorrect
-
What is the breakdown product of serotonin?
Your Answer:
Correct Answer: 5-Hydroxyindoleacetic acid
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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This question is part of the following fields:
- Neurosciences
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Question 121
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.
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This question is part of the following fields:
- Neurosciences
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Question 122
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.
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This question is part of the following fields:
- Neurosciences
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Question 123
Incorrect
-
The sella turcica is a saddle-shaped depression in which bone that houses the pituitary gland?
Your Answer:
Correct Answer: Sphenoid
Explanation:The sphenoid bone contains a saddle-shaped depression known as the sella turcica. The anterior cranial fossa is formed by the frontal, ethmoid, and a portion of the sphenoid bones. The middle cranial fossa is formed by the sphenoid and temporal bones, while the posterior cranial fossa is formed by the occipital and temporal bones.
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This question is part of the following fields:
- Neurosciences
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Question 124
Incorrect
-
Which pathway's dopamine blockade is responsible for the antipsychotic-induced extrapyramidal side effects?
Your Answer:
Correct Answer: Nigrostriatal
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.
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This question is part of the following fields:
- Neurosciences
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Question 125
Incorrect
-
What is the most probable outcome of damage to Broca's area?
Your Answer:
Correct Answer: Non-fluent aphasia
Explanation:Broca’s aphasia is also known as non-fluent aphasia, while Wernicke’s aphasia is referred to as fluent aphasia.
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.
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This question is part of the following fields:
- Neurosciences
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Question 126
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.
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This question is part of the following fields:
- Neurosciences
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Question 127
Incorrect
-
What is a typical EEG finding in individuals with Creutzfeldt-Jakob disease?
Your Answer:
Correct Answer: Slow background rhythm with paroxysmal sharp waves
Explanation:Creutzfeldt-Jakob disease is characterized by a slow background rhythm accompanied by paroxysmal sharp waves on EEG, while the remaining options are typical EEG features of the aging process.
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This question is part of the following fields:
- Neurosciences
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Question 128
Incorrect
-
In addition to alcohol, what other substance is metabolized by aldehyde dehydrogenase?
Your Answer:
Correct Answer: Serotonin
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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This question is part of the following fields:
- Neurosciences
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Question 129
Incorrect
-
Which waves are present at the onset of stage 2 sleep, in addition to k-complexes?
Your Answer:
Correct Answer: Sigma
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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This question is part of the following fields:
- Neurosciences
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Question 130
Incorrect
-
What is the accuracy of the dopamine hypothesis in explaining schizophrenia?
Your Answer:
Correct Answer: Cannabinoid agonists have been shown in animals to increase striatal dopamine release
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.
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This question is part of the following fields:
- Neurosciences
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Question 131
Incorrect
-
What structure is situated in the middle cranial fossa?
Your Answer:
Correct Answer: Foramen lacerum
Explanation:The foramen lacerum is a opening located in the middle cranial fossa at the base of the skull.
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.
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This question is part of the following fields:
- Neurosciences
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Question 132
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.
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This question is part of the following fields:
- Neurosciences
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Question 133
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.
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This question is part of the following fields:
- Neurosciences
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Question 134
Incorrect
-
A 42 year old, overweight woman presents with recurring episodes of one-sided vision loss accompanied by pain over the last 24 months. She is curious if her use of fluoxetine, which you prescribed for her depression, could be a contributing factor. What is your primary suspicion regarding her symptoms?
Your Answer:
Correct Answer: Multiple sclerosis
Explanation:The symptoms experienced by the woman are most indicative of optic neuritis, which is characterized by inflammation of the optic nerve where it connects to the eye. This typically results in temporary loss of vision in one eye, accompanied by pain during eye movement. Optic neuritis is commonly associated with multiple sclerosis. It is unlikely that the woman is experiencing an arterial occlusion, as this would cause permanent and painless vision loss. A pituitary adenoma would affect both eyes and result in permanent vision loss. The possibility of a somatoform disorder is unlikely, as the women’s symptoms align with a recognized medical diagnosis. Endophthalmitis is a serious condition that can cause permanent vision loss and requires immediate medical attention.
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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This question is part of the following fields:
- Neurosciences
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Question 135
Incorrect
-
What is a true statement about microglia?
Your Answer:
Correct Answer: It is mesodermal in origin
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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This question is part of the following fields:
- Neurosciences
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Question 136
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.
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This question is part of the following fields:
- Neurosciences
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Question 137
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.
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This question is part of the following fields:
- Neurosciences
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Question 138
Incorrect
-
What is the area of the brain that is responsible for causing the Klüver-Bucy syndrome when it experiences dysfunction on both sides?
Your Answer:
Correct Answer: Temporal lobe
Explanation: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.
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This question is part of the following fields:
- Neurosciences
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Question 139
Incorrect
-
What EEG finding has consistently been associated with the use of clozapine?
Your Answer:
Correct Answer: Decreased alpha, increased theta, increased delta
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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This question is part of the following fields:
- Neurosciences
-
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Question 140
Incorrect
-
What is a distinguishing characteristic of normal pressure hydrocephalus?
Your Answer:
Correct Answer: Incontinence
Explanation:Headache, nausea, vomiting, papilledema, and ocular palsies are symptoms of increased intracranial pressure, which are not typically present in cases of normal pressure hydrocephalus.
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.
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This question is part of the following fields:
- Neurosciences
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Question 141
Incorrect
-
What is a true statement about Wernicke's aphasia?
Your Answer:
Correct Answer: Speech is characteristically meaningless
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.
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This question is part of the following fields:
- Neurosciences
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Question 142
Incorrect
-
What substance belongs to the category of catecholamines?
Your Answer:
Correct Answer: Dopamine
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.
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This question is part of the following fields:
- Neurosciences
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Question 143
Incorrect
-
Your consultant calls you into his room to show you an interesting case. When you enter you see a middle-aged female sat in a chair. The consultant places a hairbrush next to her which she immediately picks up and starts brushing her hair with. Which of the following terms best describes this observation?:
Your Answer:
Correct Answer: Utilization behaviour
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.
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This question is part of the following fields:
- Neurosciences
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Question 144
Incorrect
-
Which one of these pathways is not associated with dopamine?
Your Answer:
Correct Answer: Limbostriatal pathway
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.
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This question is part of the following fields:
- Neurosciences
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Question 145
Incorrect
-
What is the neuroanatomical structure that was named after a seahorse due to its alleged resemblance?
Your Answer:
Correct Answer: Hippocampus
Explanation:Brain Structures and Their Etymologies
The hippocampus, with its swirling shape, was named after the seahorse, combining the Greek words ‘hippos’ (horse) and ‘kampos’ (sea-monster). Meanwhile, the cerebellum, which resembles a smaller version of the brain, was named after the Latin word for ‘little brain’. The corpus callosum, a bundle of nerve fibers connecting the two hemispheres of the brain, was named after the Latin for ‘tough body’. The hypothalamus, located below the thalamus, was named after its position. Finally, the putamen, a structure involved in movement control, comes from the Latin word for ‘that which falls off in pruning’. These etymologies provide insight into the history and development of our understanding of the brain’s structures.
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This question is part of the following fields:
- Neurosciences
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Question 146
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.
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This question is part of the following fields:
- Neurosciences
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Question 147
Incorrect
-
What is another name for the forebrain in the developing embryo?
Your Answer:
Correct Answer: Prosencephalon
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.
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This question is part of the following fields:
- Neurosciences
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Question 148
Incorrect
-
Which condition has been eliminated due to the use of highly active antiretroviral therapy (HAART) in individuals who are HIV positive?
Your Answer:
Correct Answer: Toxoplasmosis
Explanation:The use of HAART has led to a complete elimination of new cases of toxoplasmosis in individuals who are HIV positive. Studies conducted on the Edinburgh cohort have revealed a significant decrease in the occurrence of CMV by 50% during autopsy, a 68% reduction in HIVE, and complete eradication of toxoplasmosis. However, there has been a slight increase in the incidence of PML and lymphoma in this group and other samples.
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This question is part of the following fields:
- Neurosciences
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Question 149
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.
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This question is part of the following fields:
- Neurosciences
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Question 150
Incorrect
-
Which nuclei in the hypothalamus are responsible for the production and release of dopamine that is transported to the pituitary gland through the infundibulum?
Your Answer:
Correct Answer: Arcuate
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.
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This question is part of the following fields:
- Neurosciences
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Question 151
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.
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This question is part of the following fields:
- Neurosciences
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Question 152
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.
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This question is part of the following fields:
- Neurosciences
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Question 153
Incorrect
-
Which process breaks down dopamine?
Your Answer:
Correct Answer: COMT, MAO-B and MAO-A
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.
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This question is part of the following fields:
- Neurosciences
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Question 154
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.
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This question is part of the following fields:
- Neurosciences
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Question 155
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.
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This question is part of the following fields:
- Neurosciences
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Question 156
Incorrect
-
In which region of the brain is the 'Arbor vitae' situated?
Your Answer:
Correct Answer: Cerebellum
Explanation:Brain Anatomy
The brain is a complex organ with various regions responsible for different functions. The major areas of the cerebrum (telencephalon) include the frontal lobe, parietal lobe, occipital lobe, temporal lobe, insula, corpus callosum, fornix, anterior commissure, and striatum. The cerebrum is responsible for complex learning, language acquisition, visual and auditory processing, memory, and emotion processing.
The diencephalon includes the thalamus, hypothalamus and pituitary, pineal gland, and mammillary body. The thalamus is a major relay point and processing center for all sensory impulses (excluding olfaction). The hypothalamus and pituitary are involved in homeostasis and hormone release. The pineal gland secretes melatonin to regulate circadian rhythms. The mammillary body is a relay point involved in memory.
The cerebellum is primarily concerned with movement and has two major hemispheres with an outer cortex made up of gray matter and an inner region of white matter. The cerebellum provides precise timing and appropriate patterns of skeletal muscle contraction for smooth, coordinated movements and agility needed for daily life.
The brainstem includes the substantia nigra, which is involved in controlling and regulating activities of the motor and premotor cortical areas for smooth voluntary movements, eye movement, reward seeking, the pleasurable effects of substance misuse, and learning.
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This question is part of the following fields:
- Neurosciences
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Question 157
Incorrect
-
In what area of the brain does the Anton-Babinski syndrome cause damage?
Your Answer:
Correct Answer: Occipital lobe
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.
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This question is part of the following fields:
- Neurosciences
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Question 158
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.
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This question is part of the following fields:
- Neurosciences
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Question 159
Incorrect
-
Which reflex involves the motor component of cranial nerve VII?
Your Answer:
Correct Answer: Corneal reflex
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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This question is part of the following fields:
- Neurosciences
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Question 160
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.
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This question is part of the following fields:
- Neurosciences
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Question 161
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.
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This question is part of the following fields:
- Neurosciences
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Question 162
Incorrect
-
A 30-year-old woman is diagnosed with damage to the Broca's area after experiencing expressive aphasia following a car accident. Where is the Broca's area located in the brain?
Your Answer:
Correct Answer: Inferior frontal gyrus
Explanation:Broca’s area, located in the inferior frontal gyrus of the dominant hemisphere, is a crucial region for language production. It controls the motor functions necessary for speech production, and damage to this area can result in difficulties forming words and speaking. While language comprehension remains intact, the individual may experience expressive dysphasia, struggling to produce speech.
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This question is part of the following fields:
- Neurosciences
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Question 163
Incorrect
-
What is the structure that carries the middle meningeal artery?
Your Answer:
Correct Answer: Foramen spinosum
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.
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This question is part of the following fields:
- Neurosciences
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Question 164
Incorrect
-
Which structure does the spinal cord pass through to enter the cranial cavity?
Your Answer:
Correct Answer: Foramen magnum
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.
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This question is part of the following fields:
- Neurosciences
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Question 165
Incorrect
-
What EEG alterations are observed in individuals with Creutzfeldt-Jakob disease?
Your Answer:
Correct Answer: Periodic sharp wave complexes
Explanation:The typical EEG pattern for CJD includes periodic sharp wave complexes, which is a diagnostic criterion. Lewy body dementia may show generalized slow wave activity, but if it is more prominent in the temporal and parietal regions, it may indicate Alzheimer’s disease. Toxic encephalopathies, such as lithium toxicity, may show periodic triphasic waves on EEG. For more information, see Smith SJ’s article EEG in neurological conditions other than epilepsy: when does it help, what does it add? (2005).
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This question is part of the following fields:
- Neurosciences
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Question 166
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.
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This question is part of the following fields:
- Neurosciences
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Question 167
Incorrect
-
Which structure's degeneration is believed to cause the absence of cholinergic innervation observed in Alzheimer's disease?
Your Answer:
Correct Answer: Nucleus of Meynert
Explanation:The primary origin of acetylcholine in the brain is the Meynert nucleus, which is observed to be atrophied in individuals with Alzheimer’s disease. This clarifies the deficiency of acetylcholine in this disorder and the effectiveness of cholinesterase inhibitors.
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.
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This question is part of the following fields:
- Neurosciences
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Question 168
Incorrect
-
Which structure secretes adrenocorticotropic hormone in the HPA axis?
Your Answer:
Correct Answer: Pituitary
Explanation:The anterior lobe of the pituitary gland secretes adrenocorticotropic hormone.
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.
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This question is part of the following fields:
- Neurosciences
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Question 169
Incorrect
-
What is the enzyme responsible for converting 5-hydroxytryptophan into serotonin?
Your Answer:
Correct Answer: L-aromatic amino acid decarboxylase
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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This question is part of the following fields:
- Neurosciences
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Question 170
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.
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This question is part of the following fields:
- Neurosciences
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Question 171
Incorrect
-
The pineal gland secretes which of the following?
Your Answer:
Correct Answer: Melatonin
Explanation:Melatonin: The Hormone of Darkness
Melatonin is a hormone that is produced in the pineal gland from serotonin. This hormone is known to be released in higher amounts during the night, especially in dark environments. Melatonin plays a crucial role in regulating the sleep-wake cycle and is often referred to as the hormone of darkness.
The production of melatonin is influenced by the amount of light that enters the eyes. When it is dark, the pineal gland releases more melatonin, which helps to promote sleep. On the other hand, when it is light, the production of melatonin is suppressed, which helps to keep us awake and alert.
Melatonin is also known to have antioxidant properties and may help to protect the body against oxidative stress. It has been suggested that melatonin may have a role in the prevention of certain diseases, such as cancer and neurodegenerative disorders.
Overall, melatonin is an important hormone that plays a crucial role in regulating our sleep-wake cycle and may have other health benefits as well.
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This question is part of the following fields:
- Neurosciences
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Question 172
Incorrect
-
What is the term used to describe the inability to perceive multiple objects in the visual field simultaneously?
Your Answer:
Correct Answer: Simultanagnosia
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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This question is part of the following fields:
- Neurosciences
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Question 173
Incorrect
-
During which stage of sleep do sleep spindles appear on an EEG in a typical individual?
Your Answer:
Correct Answer: Stage 2
Explanation:Sleep is a complex process that involves different stages. These stages are categorized into Non-REM (NREM) and Rapid Eye Movement (REM) sleep. Each cycle of NREM and REM sleep takes around 90 to 110 minutes.
Stage 1 is the lightest stage of sleep, where the sleeper may experience sudden muscle contractions and a sense of falling. The brain waves during this stage are called theta waves.
In Stage 2, eye movement stops, and brain waves become lower. Sleep spindles and K complexes, which are rapid bursts of 12-14 Hz waves, are seen during this stage.
Stages 3 and 4 are referred to as deep sleep of delta sleep. There is no eye movement of muscle activity during these stages. Children may experience night terrors of somnambulism during these stages.
REM sleep is characterized by rapid, shallow breathing and rapid, jerky eye movements. Most dreaming occurs during REM sleep.
Overall, the different stages of sleep are important for the body to rest and rejuvenate. Understanding these stages can help individuals improve their sleep quality and overall health.
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This question is part of the following fields:
- Neurosciences
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Question 174
Incorrect
-
Which statement about 5-Hydroxyindoleacetic acid (5-HIAA) is accurate?
Your Answer:
Correct Answer: Low CSF levels are found in people with depression
Explanation:Depression, suicidality, and aggression have been linked to low 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.
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This question is part of the following fields:
- Neurosciences
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Question 175
Incorrect
-
Which artery blockage is most likely to cause Broca's aphasia?
Your Answer:
Correct Answer: Middle cerebral
Explanation:Brain Blood Supply and Consequences of Occlusion
The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.
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This question is part of the following fields:
- Neurosciences
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Question 176
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.
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This question is part of the following fields:
- Neurosciences
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Question 177
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.
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This question is part of the following fields:
- Neurosciences
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Question 178
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.
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This question is part of the following fields:
- Neurosciences
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Question 179
Incorrect
-
In what circumstances are neurofibrillary tangles less commonly observed?
Your Answer:
Correct Answer: Vascular dementia
Explanation:Tauopathies exhibit tangles, but vascular dementia is not classified as one.
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.
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This question is part of the following fields:
- Neurosciences
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Question 180
Incorrect
-
Which substance is 5-HIAA a metabolite of?
Your Answer:
Correct Answer: Serotonin
Explanation: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.
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This question is part of the following fields:
- Neurosciences
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Question 181
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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This question is part of the following fields:
- Neurosciences
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Question 182
Incorrect
-
What gas functions as a neurotransmitter?
Your Answer:
Correct Answer: Carbon monoxide
Explanation:It’s important to differentiate between nitrogen and nitrous oxide, as they have distinct properties. Nitrogen is not a neurotransmitter, while nitrous oxide is sometimes used for its anesthetic and analgesic effects.
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.
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This question is part of the following fields:
- Neurosciences
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Question 183
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.
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This question is part of the following fields:
- Neurosciences
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Question 184
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.
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This question is part of the following fields:
- Neurosciences
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Question 185
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.
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This question is part of the following fields:
- Neurosciences
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Question 186
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.
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This question is part of the following fields:
- Neurosciences
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Question 187
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.
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This question is part of the following fields:
- Neurosciences
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Question 188
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.
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This question is part of the following fields:
- Neurosciences
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Question 189
Incorrect
-
A 45-year-old man experiences a stroke caused by a ruptured berry aneurysm in the middle cerebral artery.
What tests would you anticipate to show abnormalities?Your Answer:
Correct Answer: Luria's motor test
Explanation:Damage to the frontal lobe can impact sequencing abilities, as evidenced by Luria’s motor test which involves performing a sequence of fist-edge-palm movements. Additionally, the anterior cerebral artery is responsible for supplying blood to the frontal lobes.
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This question is part of the following fields:
- Neurosciences
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Question 190
Incorrect
-
Which type of seizure is most commonly associated with a polyspike and wave discharge pattern in the range of 3-6 Hz?
Your Answer:
Correct Answer: Myoclonic
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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This question is part of the following fields:
- Neurosciences
-
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Question 191
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).
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This question is part of the following fields:
- Neurosciences
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Question 192
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.
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This question is part of the following fields:
- Neurosciences
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Question 193
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.
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This question is part of the following fields:
- Neurosciences
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Question 194
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.
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This question is part of the following fields:
- Neurosciences
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Question 195
Incorrect
-
Which symptom would indicate a hydrocephalus that is communicating rather than non-communicating?
Your Answer:
Correct Answer: Ataxia
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.
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This question is part of the following fields:
- Neurosciences
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Question 196
Incorrect
-
Which of the following is not a description of a dopamine pathway in the brain that is relevant to schizophrenia?
Your Answer:
Correct Answer: Median raphe nucleus to VTA
Explanation:The median raphe nucleus is a group of neurons located in the brainstem that plays a crucial role in regulating mood, anxiety, and stress. It is connected to various brain regions, including the ventral tegmental area (VTA), which is a key component of the brain’s reward system.
The connection between the median raphe nucleus and the VTA is important because it allows for the modulation of reward-related behaviors and emotions. The median raphe nucleus sends serotonergic projections to the VTA, which can influence the release of dopamine, a neurotransmitter that is associated with pleasure and reward.
Studies have shown that disruptions in the communication between the median raphe nucleus and the VTA can lead to various psychiatric disorders, such as depression and addiction. Therefore, understanding the mechanisms underlying this connection is crucial for developing effective treatments for these conditions.
In summary, the connection between the median raphe nucleus and the VTA is an important pathway for regulating reward-related behaviors and emotions, and disruptions in this pathway can lead to psychiatric disorders.
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This question is part of the following fields:
- Neurosciences
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Question 197
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.
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This question is part of the following fields:
- Neurosciences
-
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Question 198
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.
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This question is part of the following fields:
- Neurosciences
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Question 199
Incorrect
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What is the accurate statement about the pathology of schizophrenia?
Your Answer:
Correct Answer: Brain volume of affected individuals is often reduced
Explanation:While ventricular enlargement is often observed in individuals with schizophrenia, it is not a definitive indicator of the condition as it can also be present in other disorders.
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.
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This question is part of the following fields:
- Neurosciences
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Question 200
Incorrect
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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.
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This question is part of the following fields:
- Neurosciences
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