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@INPROCEEDINGS{Kedo:1048666,
author = {Kedo, Olga and Lothmann, Kimberley and Schiffer, Christian
and Mohlberg, Hartmut and Dickscheid, Timo and Amunts,
Katrin},
title = {{T}he hippocampal formation mapped in the {B}ig{B}rain:
{T}he deep-learning supported high-resolution mapping and
3{D} reconstruction},
reportid = {FZJ-2025-04794},
year = {2025},
abstract = {The hippocampal formation (HF) plays an important role in
memory, with its subdivisions being involved in its differnt
functions and neuropathologies. The hippocampus has been
parcellated in different ways both in histological and MRI
studies [1, 2]. In the BigBrain, 3D rendering of the
hippocampus was performed, based on the main hippocampal
subdivisions, which were revealed through unfolding and
unsupervised clustering of laminar and morphological
features [3]. However, this parcellation was not detailed
enough, e.g. in the field of the subicular complex.We
cytoarchitectonically identified and mapped in 10 postmortem
brains and generated probabilistic maps of CA1, CA2, CA3,
CA4, Fascia dentata (FD), prosubiculum (ProS), subiculum
(Sub), presubiculum (PreS), parasubiculum (PaS),
transsubiculum (TrS), hippocampal-amygdaloid transition area
(HATA) and entorhinal cortex (EC) [4]. Based on this
research, we mapped HF in the BigBrain and generated the 3D
maps of HF in the BigBrain template [5].Cytoarchitectonic
mapping of 12 structures was performed in at least each 15th
serial histological sections in the web-based annotation
tool MicroDraw at 1-micron resolution in-plane in the
BigBrain. Subsequently, a Deep Learning Workflow was
utilized to 3D-reconstruct the structures. Convolutional
Neural Networks were trained for image segmentation in the
sections lying between those manually mapped using ATLaSUI
[6]. The annotations of each structure were non-linearly
transformed to the sections of the 3D reconstructed BigBrain
space at 20-micron isotropic resolution, and was further
visualized using the Neuroglancer.We have identified 12
cytoarchitectonic structures of HF in the BigBrain and
analyzed their macroanatomy. The volumes of HF in the
BigBrain were compared with those from the previous sample
of 10 brains.Fasciola cinerea (FD in its mediocaudal
extension) was larger in the left hemisphere, while it was
minuscule on the right. Left ProS extended onto dorsomedial
surface of the parahippocampal gyrus (PHG), while the right
ProS almost does not appear on the surface. Caudally, PreS
occupied medial surface of the PHG. TrS abutted on PreS
ventrally. Caudal TrS bordered the temporo-parieto-occipital
proisocortex laterally, while rostral TrS abutted upon area
35. PaS replaced TrS rostrally. Rostrally, both hemispheres
had three Digitationes hippocampi respectively.The
high-resolution (20 μm) whole-brain histological references
of HF were generated on the basis of the BigBrain. These
maps allow styding and exploring neighborhood relationships
between the structures. They will be publicly available on
the EBRAINS platform and integrated with the BigBrain model
(https://go.fzj.de/bigbrain/). The maps can extend those of
the piriform cortex in the BigBrain [7] to represent two
hubs of limbic system [8]. Wisse L.E.M. et al. (2017)
Hippocampus, 27(1): p. 3-11. Yushkevich P.A. et al. (2015),
Neuroimage, 111: p. 526-41. DeKraker J. et al. (2020),
Neuroimage, 206: p. 116328. Palomero-Gallagher N. et al.
(2020), Brain Struct Funct, 225(3): p. 881-907. Amunts K. et
al. (2013), Science, 340(6139): p. 1472-5. Schiffer C. et
al. (2021), Neuroimage, 240: p. 118327. Kedo O. et al.
(2024), Anatomia, 3(2): p. 68–92. Catani M. et al. (2013),
Neurosci Biobehav Rev, 2013. 37(8): p. 1724-37.},
month = {Nov},
date = {2025-11-28},
organization = {INM Retreat 2025, Jülich (Germany),
28 Nov 2025 - 28 Nov 2025},
subtyp = {After Call},
cin = {INM-1},
cid = {I:(DE-Juel1)INM-1-20090406},
pnm = {5251 - Multilevel Brain Organization and Variability
(POF4-525)},
pid = {G:(DE-HGF)POF4-5251},
typ = {PUB:(DE-HGF)24},
doi = {10.34734/FZJ-2025-04794},
url = {https://juser.fz-juelich.de/record/1048666},
}