Comparison of histological delineations of medial temporal lobe cortices by four independent neuroanatomy laboratories
Creators: name: Dalton, Marshall A.
name: Bakker, Arnold
name: Denning, Amanda
name: del Mar Arroyo‐Jiménez, María
name: Baumeister, Hannah
name: Lim, Sydney
name: Schuck, Theresa
name: Berron, David
name: Olsen, Rosanna K.
name: del Pilar Marcos‐Rabal, María
name: Insausti, Ricardo
name: La Joie, Renaud
name: Ding, Song‐Lin
name: Lee, Edward B.
name: de la Rosa Prieto, Carlos
name: Augustinack, Jean C.
name: Amunts, Katrin
name: Wisse, Laura E. M.
name: Tran, Tammy T.
name: Bedard, Madigan L.
name: Ittyerah, Ranjit
name: Irwin, David J.
name: Trotman, Winifred
name: Yushkevich, Paul
name: Puliyadi, Vyash
name: Mazloum‐Farzaghi, Negar
name: Adams, Jenna N.
name: Wuestefeld, Anika
name: Wang, Lei
name: Buendia, Esther
name: Artacho‐Pérula, Emilio
name: Daugherty, Ana M.
name: Vela, Alicia
name: Canada, Kelsey L.
name: de Flores, Robin
name: Chung, Eunice
name: Hodgetts, Carl J.
name: Lopez, Monica Munoz
name: de Onzoño Martin, Maria Mercedes Iñiguez
name: Kedo, Olga
Publisher: name: Wiley
Year: 2024

description: The medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimer's disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical schools rely on different cytoarchitectonic definitions of these subregions, it is unclear to what extent their delineations of MTL cortex subregions overlap. Here, we provide an overview of cytoarchitectonic definitions of the entorhinal and parahippocampal cortices as well as Brodmann areas (BA) 35 and 36, as provided by four neuroanatomists from different laboratories, aiming to identify the rationale for overlapping and diverging delineations. Nissl-stained series were acquired from the temporal lobes of three human specimens (two right and one left hemisphere). Slices (50 μm thick) were prepared perpendicular to the long axis of the hippocampus spanning the entire longitudinal extent of the MTL cortex. Four neuroanatomists annotated MTL cortex subregions on digitized slices spaced 5 mm apart (pixel size 0.4 μm at 20× magnification). Parcellations, terminology, and border placement were compared among neuroanatomists. Cytoarchitectonic features of each subregion are described in detail. Qualitative analysis of the annotations showed higher agreement in the definitions of the entorhinal cortex and BA35, while the definitions of BA36 and the parahippocampal cortex exhibited less overlap among neuroanatomists. The degree of overlap of cytoarchitectonic definitions was partially reflected in the neuroanatomists' agreement on the respective delineations. Lower agreement in annotations was observed in transitional zones between structures where seminal cytoarchitectonic features are expressed less saliently. The results highlight that definitions and parcellations of the MTL cortex differ among neuroanatomical schools and thereby increase understanding of why these differences may arise. This work sets a crucial foundation to further advance anatomically-informed neuroimaging research on the human MTL cortex.