Mapping hippocampus structure and function by the Cognitive NeuroInformatics Lab

From a phylogenesis standpoint, the hippocampus is among the oldest brain regions.

From histological work, the hippocampus is known to be organized into different subfields arranged along a medial-lateral and a ventro-dorsal axis as illustrated in the figure below:

In line with their different microstructural profiles, the different subfields are also known to have different anatomical connections (white matter tracts).

However, functional studies (such as fMRI studies) primarily highlight a differentiation within the hippocampus along the longitudinal axis (that is, the anterior-posterior axis in the human brain).

This functional organization appears to relate to behavioral dimensions. Our work using data-driven approaches support two hypotheses: an emotion-cognition gradient and a self-centric-word-centric processing dimension.

Hence, several organizational dimensions can be seen in the hippocampus. Our work in the healthy adult population shows that the patterns of co-plasticity (that is covariance in morphological measurements between the hippocampus and other brain region) reflect these multiples dimensions:

Nevertheless, neurodenegeration in dementia appears to follows functional differentiation along the longitudinal axis, with posterior regions together differentiating from anterior regions in their co-atrophy patterns in Alzheimer’s disease (Plachti et al., 2020):