Fig. 2. Topological representations of hippocampal functional organisation and their heritability.

A. Connectivity gradients of subfield-isocortical FC for SUB (left), CA (middle) and DG (right). Gradient 1 ($G{1}_{FC}$) depicts an anterior-posterior (A-P) connectivity axis, whereas Gradient 2 ($G{2}_{FC}$) displays a medial-lateral axis. B. Variations in hippocampal-isocortical FC across the $G{1}_{FC}$ projected on the isocortex (Pearson’s r-values). Lower r-values (blue) indicate FC similarity between the anterior subfield portions and isocortex, whereas higher r-values (yellow) that of the posterior subfield portions and isocortex. C. Subfield-isocortical FC-heritability decomposed into its gradient representations. Primary gradient of FC-heritability $G1\left(h_{FC}^2\right)$ depicts an A-P separation of the $h^2$ profiles for all subfields. D. Heritability of primary and secondary functional gradient loadings ($h^2\left(G{1}_{FC}\right)$ and $h^2\left(G{2}_{FC}\right)$) for each subfield vertex. Heritability analysis was run on $G{1}_{FC}$ and $G{2}_{FC}$ from Panel A and revealed a $h^2$ score for gradient loadings for each vertex.