Neuroanatomy: hippocampal vulnerability: practice question

A Anatomy 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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Anatomy · Neuroanatomy: hippocampal vulnerability

Sample item

A man who survives a cardiac arrest has persistent anterograde amnesia. MRI shows selective loss of neurones in the hippocampal sector most vulnerable to hypoxia. Which sector is it?

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

The answer and the reasoning

D. CA1 (Sommer sector)

Pyramidal neurones of CA1 are highly sensitive to ischaemia and hypoxia, and their loss produces memory impairment. This selective vulnerability is called the Sommer sector.

Option by option

  • A. Granule layer of the dentate gyrus

    Dentate granule cells are comparatively resistant to ischaemia.

  • B. Subiculum

    The subiculum is the main output region and is relatively resistant.

  • C. CA3

    CA3 is less vulnerable to hypoxia than CA1 and is the site of mossy fibre input.

  • D. CA1 (Sommer sector) (correct)

    Correct. CA1 pyramidal cells are the most vulnerable to hypoxia.

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.

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Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is D, CA1 (Sommer sector). Pyramidal neurones of CA1 are highly sensitive to ischaemia and hypoxia, and their loss produces memory impairment.

Why is "Granule layer of the dentate gyrus" not the answer?

Dentate granule cells are comparatively resistant to ischaemia.

Why is "Subiculum" not the answer?

The subiculum is the main output region and is relatively resistant.

Why is "CA3" not the answer?

CA3 is less vulnerable to hypoxia than CA1 and is the site of mossy fibre input.

What concept does this question test?

It tests Neuroanatomy: hippocampal vulnerability in Anatomy. This selective vulnerability is called the Sommer sector.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Neuroanatomy: hippocampal vulnerability?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.