Neurophysiology and special senses: cerebellar laterality: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Neurophysiology and special senses: cerebellar laterality

Sample item

A patient has an infarct of the right cerebellar hemisphere. Limb ataxia appears on which side, and why?

ABoth sides equally, because the cerebellum is bilateralBThe left side, because the cerebellum controls the opposite limbsCThe right side, because the cerebellar pathways cross twiceDThe left side, because the cerebellar pathways cross once

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. The right side, because the cerebellar pathways cross twice

Cerebellar outflow crosses in the superior cerebellar peduncle on its way to the red nucleus and thalamus, and the corticospinal tract crosses again, so each hemisphere affects the same side of the body. A right hemisphere lesion causes right limb ataxia.

Option by option

A. Both sides equally, because the cerebellum is bilateral
Hemisphere lesions give mainly unilateral, same-sided limb signs, not bilateral equal signs.
B. The left side, because the cerebellum controls the opposite limbs
The cerebellum does not control the opposite limbs.
C. The right side, because the cerebellar pathways cross twice (correct)
Correct. Double crossing means a cerebellar lesion affects the ipsilateral limbs.
D. The left side, because the cerebellar pathways cross once
A single crossing would give a contralateral effect, which does not occur.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, The right side, because the cerebellar pathways cross twice. Cerebellar outflow crosses in the superior cerebellar peduncle on its way to the red nucleus and thalamus, and the corticospinal tract crosses again, so each hemisphere affects the same side of the body.

Why is "Both sides equally, because the cerebellum is bilateral" not the answer?

Hemisphere lesions give mainly unilateral, same-sided limb signs, not bilateral equal signs.

Why is "The left side, because the cerebellum controls the opposite limbs" not the answer?

The cerebellum does not control the opposite limbs.

Why is "The left side, because the cerebellar pathways cross once" not the answer?

A single crossing would give a contralateral effect, which does not occur.

What concept does this question test?

It tests Neurophysiology and special senses: cerebellar laterality in Physiology. A right hemisphere lesion causes right limb ataxia.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neurophysiology and special senses: cerebellar laterality?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.