Neurophysiology: cerebellar climbing fibres: 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: cerebellar climbing fibres

Sample item

In the cerebellum, a single Purkinje cell receives input from one climbing fibre and thousands of parallel fibres. From which structure do climbing fibres arise, and what do they evoke?

ADentate nucleus, evoking simple spike firingBPontine nuclei, evoking simple spike firingCInferior olive, evoking complex spike firingDVestibular nuclei, evoking complex spike firing

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

The answer and the reasoning

C. Inferior olive, evoking complex spike firing

Climbing fibres arise from the contralateral inferior olive and produce large, all-or-none complex spikes in Purkinje cells. Mossy fibres, from the pontine and other nuclei, act through granule cells and parallel fibres to produce simple spikes.

Option by option

A. Dentate nucleus, evoking simple spike firing
The dentate nucleus is a cerebellar output nucleus and not a source of climbing fibres.
B. Pontine nuclei, evoking simple spike firing
Pontine nuclei give rise to mossy fibres, which produce simple spikes.
C. Inferior olive, evoking complex spike firing (correct)
Correct. Olivary climbing fibres evoke the complex spike.
D. Vestibular nuclei, evoking complex spike firing
Vestibular nuclei send mossy-type fibres and do not give rise to climbing fibres.

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, Inferior olive, evoking complex spike firing. Climbing fibres arise from the contralateral inferior olive and produce large, all-or-none complex spikes in Purkinje cells.

Why is "Dentate nucleus, evoking simple spike firing" not the answer?

The dentate nucleus is a cerebellar output nucleus and not a source of climbing fibres.

Why is "Pontine nuclei, evoking simple spike firing" not the answer?

Pontine nuclei give rise to mossy fibres, which produce simple spikes.

Why is "Vestibular nuclei, evoking complex spike firing" not the answer?

Vestibular nuclei send mossy-type fibres and do not give rise to climbing fibres.

What concept does this question test?

It tests Neurophysiology: cerebellar climbing fibres in Physiology. Mossy fibres, from the pontine and other nuclei, act through granule cells and parallel fibres to produce simple spikes.

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: cerebellar climbing fibres?

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.