Block 5 Neuro Blood Supply And Diencephalon MCQ's

Olfaction is the correct answer because the sense of smell does not rely heavily on the thalamus for sensory relay to the cortex. Unlike other sensory modalities such as pain, light touch, proprioception, and vibratory sense, which all involve the thalamus in relaying sensory information to the cortex, olfaction bypasses the thalamus and sends signals directly to the olfactory cortex. This direct pathway allows for a faster and more direct processing of smells, which is why smells can evoke strong emotional and memory responses.

The pacinian corpuscles are responsible for detecting vibrations and pressure in the skin. The VPL nucleus of the thalamus receives sensory input from the body, including proprioception and touch. Since the activation of pacinian corpuscles in the left hand would be considered touch sensation, the VPL nucleus on the right side would be primarily responsible for processing this input.

Based on the information given, the occlusion of the Anterior Cerebral Artery supplying the right hemisphere would result in a deficit in motor and sensory function in the left lower limb. This is because the Anterior Cerebral Artery supplies blood to the motor and sensory areas of the brain that control the opposite side of the body. Therefore, if the right hemisphere is affected, it will lead to deficits in the left side of the body, including the left lower limb.

The posterior inferior cerebellar artery (PICA) is an arterial branch of the vertebral system that supplies the brain. It is responsible for providing blood to the inferior surface of the cerebellum, as well as portions of the medulla and the posterior part of the brainstem. The other options listed are also arteries that supply blood to the brain, but they are not branches of the vertebral system. The anterior cerebral artery and middle cerebral artery are branches of the internal carotid artery, while the posterior communicating artery and anterior communicating artery are branches of the circle of Willis.

The ventral anterior nucleus receives neuronal inputs from the basal ganglia which includes the substantia nigra and the globus pallidus. It also has inputs from the cerebellum it sends out neuronal input to the supplementary motor cortex AND to primary motor cortex.

The nuclei of the hypothalamus that regulate feeding behaviors are the dorsomedial nucleus, lateral nucleus, and ventromedial nucleus. These specific nuclei are involved in the control of hunger and satiety, as well as the regulation of food intake and energy balance. They receive input from various hormonal and neural signals related to appetite and play a crucial role in the overall regulation of feeding behaviors.

The symptoms described in the patient suggest a lesion in the brainstem, specifically in the lateral medulla. This is known as lateral medullary syndrome or Wallenberg syndrome. The PICA supplies blood to the lateral medulla, and occlusion of this artery can lead to the symptoms observed in the patient, including loss of pain and temperature sense on the right side of the body (contralateral to the lesion), decreased sense of taste on the left side, hoarseness of voice, dizziness, and nausea. Therefore, the occlusion of the Posterior Inferior Cerebellar Artery (PICA) is the most likely cause of the patient's symptoms.

The paraventricular nucleus of the hypothalamus is responsible for regulating thirst and water balance in the body. Damage to this structure can lead to excessive thirst and drinking, as seen in the patient's symptoms of polyuria and excessive thirst. The infarcted area in the diencephalon, as revealed by the CT scan, suggests a lesion in the paraventricular nucleus of the hypothalamus, further supporting this explanation.

The correct answer is Middle Cerebral Artery - Deficits to right upper limb. This is because the middle cerebral artery supplies blood to the motor and sensory areas of the brain that control movement and sensation in the upper limb. Therefore, a severe stroke in the middle cerebral artery would result in deficits in the right upper limb.

The symptoms described in the question, including loss of taste, loss of pain and temperature on the left side below the neck, hoarseness of voice, and slight ataxia, are consistent with a small stroke in the right posterior inferior cerebellar artery (PICA). The PICA supplies blood to the lateral medulla, which controls sensory and motor functions in the head and neck. A stroke in this artery can result in a variety of symptoms, including those described in the question.

The middle cerebral artery supplies blood to the lateral surface of the brain, including the areas responsible for language comprehension. Since the patient has difficulty comprehending spoken language, it suggests that the branches of the middle cerebral artery have been compromised.

The correct answer is the Spinal nucleus of V (trigeminal). The trigeminal nerve is responsible for transmitting sensory information from the face, including temperature perception, to the brain. The Spinal nucleus of V specifically relays this information to the thalamus, which then processes and interprets the sensory input. Since the question mentions the perception of temperature on the tongue, it is likely that the trigeminal nerve, specifically the Spinal nucleus of V, is involved in relaying this information.

The anterior nucleus of the thalamus has both afferent and efferent limbic connections. It receives inputs from various limbic structures, such as the hippocampus and amygdala, and sends outputs to the cingulate gyrus and other limbic regions. These connections play a crucial role in emotional processing, memory, and behavior. Therefore, damage to the limbic thalamus, specifically the anterior nucleus, can result in impairments in these functions.

If the lateral nucleus of the hypothalamus is lesioned or destroyed, it would cause starvation. The lateral nucleus is responsible for stimulating hunger and increasing food intake. When this nucleus is damaged, it disrupts the normal regulation of appetite and leads to a decrease in food consumption, ultimately resulting in starvation.

The Dorsomedial nucleus may be related to her problem because it is involved in regulating sleep and wakefulness. This nucleus is part of the hypothalamus, which plays a crucial role in controlling sleep and wake cycles. If there is a dysfunction or imbalance in the Dorsomedial nucleus, it could lead to excessive sleepiness or difficulty staying awake, as observed in the friend falling asleep during lectures and group activities.

An occlusion of the posterior cerebral artery would result in a loss of voluntary motor function and an oculomotor nerve palsy. The posterior cerebral artery supplies blood to the occipital lobe, which is responsible for processing visual information, and the oculomotor nerve controls eye movement. Therefore, a blockage in this artery would lead to a loss of voluntary motor function and an oculomotor nerve palsy.

The dark shaded area in the diagram represents a lesion resulting from an embolus. The location of the lesion in the lower pons suggests that the artery affected is a branch of the basilar artery. Among the given options, the only artery that is a branch of the basilar artery is the paramedian branch. Therefore, the correct answer is the paramedian branch of the basilar artery.

The posterior area of the hypothalamus contains nuclei that are important for learning and memory circuits. These nuclei play a role in the consolidation and retrieval of memories.

An infarct involving the hypothalamus would most likely result from occlusion of the anterior cerebral artery. The anterior cerebral artery supplies blood to the frontal lobes, corpus callosum, and the medial aspects of the cerebral hemispheres, including the hypothalamus. Therefore, occlusion of this artery would lead to a lack of blood supply to the hypothalamus, resulting in an infarct in this region.