A shared hippocampal hub for anxiety and memory contrasts with depression-specific circuitry: A high-resolution 7T...

Hippocampal dysfunction is implicated in both memory and emotion processing, but the precise functional organization of these processes across hippocampal subdivisions and their interactions with various brain networks remain unresolved. Leveraging high-resolution 7T fMRI data from the Human Connectome Project (n = 158), we calculated the voxel-wise and brain-wide functional connectivity to reveal the functional gradient of the hippocampus. Functional subregions were identified by contrasting gradient values between high- and low-functioning groups stratified by either emotional symptoms (anxiety/depression) or memory performances (working/episodic memory). ROI-level contributions were assessed via correlations between the brain-wide connectivity of the hippocampal-subregions and behavioral measures. A primary longitudinal functional gradient spanned the hippocampus, revealing both shared and distinct emotion-memory mappings. After FDR correction, anxiety, working memory and episodic memory converged on the left middle-medial hippocampus, while depression localized specifically to the right anterior-lateral subregion. Strikingly, hippocampal-subregion connectivity to the visual network exhibited opposing associations: stronger connectivity correlated with fewer emotional symptoms but better memory performances. We delineate a fine-grained functional map within the hippocampus, identifying the left middle-medial hub for anxiety and memory and the right anterior-lateral locus specific to depression. Strengthening the connectivity of different subregions to the visual network might promote mental health in terms of both emotion and memory.