Thread by @hipposubfields

Today we continue our thread series discussing anatomical variability in the medial temporal lobe (MTL). Today’s topic is anatomical variability in the hippocampal head with a focus on the hippocampal digitations. 🍤🤓📢

#SubfieldWednesday (1/n)

But first, what do we mean by the hippocampal head? We are talking about the anterior part of the hippocampus that contains or is adjacent to the uncus.

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Now what about those “hippocampal digitations” ?

Ding & Van Hoesen (2015) describe external and internal digitations. The external digitations are the “bumps” that extend dorsally and the interior digitations are the “bumps” that extend ventrally.

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According to Ding & Van Hoesen (2015), most hippocampi have 3 digitations, but some people have 2 or 4 (or more).

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Q: Which subfields are contained in the digitations?
A: CA1 and subicular regions.

See figure below to see two examples of hippocampal subfields overlaid onto hippocampi with variable numbers of digitations.

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Quick aside: It is important to remember that hippocampal digitations are different from “dentations” recently describes by Beattie et al, Neuropsychol, 2017.

doi.org/10.1016/j.neur…

We will have a different thread on those!

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Now for the audience participation part! Have you come across any brains that have 4 or more hippocampal digitations? If so, comment below and post a screenshot!

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