Thread by @hipposubfields

Drum roll please...it's time for our very first #SubfieldWednesday!

One thing you might be wondering is: How many subfields are there in the human hippocampus and what are they called??

The answer actually depends on who you ask! Let me explain more!

#SubfieldWednesday

Most people who study the hippocampal subfields with high resolution MRI recognize CA1, CA2, CA3, CA4, dentate gyrus (DG), and the subiculum as the major subfields of the hippocampus.

That means there are five...right?

#SubfieldWednesday

Well, some researchers also divide the subicular region into the subiculum (proper), presubiculum, and parasubiculum.

So there are eight...?

#SubfieldWednesday

Another nuance to this story is that the CA4 region is not universally recognized and this subfield is referred to as the “hillus” region of the dentate gyrus by some neuroanatomists.

#SubfieldWednesday

Another subfield that some (but not all) neuroanatomists recognize is the prosubiculum. While some think it should get it's own label, others believe is just a "transition region" between the two "real" subfields CA1 and subiculum

#SubfieldWednesday

Here are all the references for the screenshots:

Parekh, M. B., Rutt, B. K., Purcell, R., Chen, Y., & Zeineh, M. M. (2015). Ultra-high resolution in-vivo 7.0 T structural imaging of the human hippocampus reveals the endfolial pathway. Neuroimage, 112, 1-6.

Insausti, R., & Amaral, D. G. (2003). Hippocampal formation. In The Human Nervous System: Second Edition (pp. 871-914). Elsevier Inc..

Ding, S. L., & Van Hoesen, G. W. (2015). Organization and detailed parcellation of human hippocampal head and body regions based on a combined analysis of cyto‐and chemoarchitecture. Journal of Comparative Neurology, 523(15), 2233-2253.

Zeidman, P., & Maguire, E. A. (2016). Anterior hippocampus: the anatomy of perception, imagination and episodic memory. Nature Reviews Neuroscience, 17(3), 173-182.