Neuroscience Test

Question 1

A 43-year-old man sustains a wound to the lateral neck.
This results in weakness of elevation and retraction of the shoulder on the ipsilateral side and difficulty turning the head up and toward the contralateral side.
No sensory changes are present.
Which of the following nerves most likely has been injured?

Accepted Answer

Spinal accessory

Answer

Axillary

Answer

Lateral cord of the brachial plexus

Answer

Phrenic

Answer

Suprascapular

Question 2

An investigator is studying normal sleep patterns in healthy men and women. Saccadic motions of the eyes are seen approximately 90 minutes after the volunteers fall asleep. Which of the following is most likely to be observed in the volunteers during this period of saccadic eye movements?

Accepted Answer

An EEG pattern resembling that of the walking state

Answer

Difficulty awakening

Answer

Hyperactive muscle tone

Answer

Increased movements

Answer

Irregular respiratory rhythm

Question 3

Drug X applied to a nerve axon decreases the duration of the action potential without affecting the resting potential or peak amplitude of the action potential. Which of the following is the most likely mechanism of action of Drug X?

Accepted Answer

Increase in the rate of voltage-dependent changes in K + permeability

Answer

Block of voltage-dependent Na + permeability

Answer

Decrease in the rate of Na + inactivation

Answer

Decrease in voltage-dependent Na + permeability

Answer

Inhibition of the Na + –K + pump

Question 4

A 65-year-old man has loss of pain and temperature sensation on the right side of the face and from the neck down on the left. Examination shows partial paralysis of the soft palate, larynx, and pharynx, and ataxia, all on the right. The most likely cause of these findings is thrombosis to which of the following arteries?

Accepted Answer

Right posterior inferior cerebellar

Answer

Basilar

Answer

Left posterior inferior cerebellar

Answer

Right superior cerebellar

Answer

Left superior cerebellar

Question 5

A 45-year-old man has a progressively severe headache. Funduscopic examination discloses blurred margins and bulging of the optic discs. The retinal veins are engorged and show no pulsatile flow. Which of the following is the mechanism most likely to explain these findings?

Accepted Answer

Increased intracranial pressure

Answer

Acute occlusion of the retinal artery

Answer

Demyelination of the optic nerve

Answer

Inflammation of the anterior chamber

Answer

Inflammation of the optic nerve

Question 6

A 4-month-old boy is brought to the physician by his mother for a well-child examination. He is at the 98th percentile for head circumference. Physical examination shows dilation of the scalp veins and spasticity of the lower extremities. The physician suspects excessive cerebrospinal fluid accumulation in the ventricular system of the brain. The source of this fluid is most likely which of the following?

Accepted Answer

Choroid plexus

Answer

Dura mater

Answer

Pia mater

Answer

Roof of the third ventricle

Question 7

A 68-year-old woman is brought to the physician by her husband because of strange behavior. The previous evening, she had gotten up suddenly from the dinner table and started to undress in front of guests. Further questioning discloses a 1-year history of a progressive change in behavior. She writes everything down on a notepad; otherwise, she forgets. She cannot remember the names of her four grandchildren or the date of her wedding anniversary. These symptoms are most likely associated with a deficit in which of the following?

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Glucose 6-phosphate dehydrogenase

Answer

Insulin

Answer

Serotonin

Question 8

A 50-year-old man has had gradually progressive hand weakness. He has atrophy of the forearm muscles, fasciculations of the muscles of the chest and arms, hyperreflexia of the lower extremities, and extensor plantar reflexes. Sensation is not impaired. Which of the following is the most likely diagnosis?

Accepted Answer

Amyotrophic lateral sclerosis

Answer

Dementia, Alzheimer type

Answer

Guillain-Barré syndrome

Answer

Multiple cerebral infarcts

Answer

Multiple sclerosis

Question 9

An 8-year-old boy is brought to the physician by his mother because he is not paying attention in class. His mother says that his teacher has described his in-school behavior as “frequently stopping what he is doing and then blinking and making chewing movements.” His mother has noticed that he sometimes “stares off into space” and seems to be daydreaming. Physical examination shows no abnormalities. An EEG during one of the episodes shows generalized spike-and-wave bursts at 3 Hz per second. This patient most likely has which of the following types of seizures?

Accepted Answer

Absence

Answer

Akinetic

Answer

Complex partial

Answer

Generalized tonic-clonic

Answer

Myoclonic

Question 10

A previously healthy 18-year-old man is brought to the emergency department because of fever, a poorly localized headache, and a stiff neck for 12 hours. The symptoms were preceded by nasal congestion, muscle aches, and chills 3 days ago. His temperature is 38.7°C (101.6°F). Physical examination shows nuchal rigidity and photophobia. There is no papilledema. Neurologic examination shows no focal findings. Which of the following is the most likely diagnosis?

Accepted Answer

Acute meningitis

Answer

Classic migraine

Answer

Cluster headache

Answer

Idiopathic intracranial hypertension

Answer

Subarachnoid hemorrhage

Answer

Temporal arteritis

Answer

Tension-type headache