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Updated: Jun 1, 2025
Individualized rTMS Treatment for Depression using an fMRI-Based Targeting Method
Published on: August 2, 2021
Functional connectivity analyses of individual hippocampal subregions in major depressive disorder with
Hui Sun1, Dundi Xu1, Qinyao Sun2
1College of Electrical Engineering, Sichuan University, Chengdu 610065, China.
Insights
Major depressive disorder (MDD) involves altered hippocampus connectivity, particularly in the left tail region. Electroconvulsive therapy (ECT) normalized these connections, which were linked to synaptic and neurogenesis pathways.
Area of Science:
- Neuroscience
- Psychiatry
- Genomics
Background:
- The hippocampus is implicated in major depressive disorder (MDD) neuropathology.
- Previous studies used group-level atlases, missing individual variability in hippocampal subregions.
- The molecular basis of hippocampal functional impairments in MDD is not well understood.
Purpose of the Study:
- To investigate functional disruptions and recovery in individual hippocampal subregions in MDD patients before and after electroconvulsive therapy (ECT).
- To link functional connectivity differences to transcriptomic profiles for understanding molecular mechanisms.
Main Methods:
- Employed a group-guided individual functional parcellation for precise hippocampal subregion definition.
- Conducted resting-state functional connectivity (FC) analysis on individual hippocampal subregions.
- Utilized spatial association between FC differences and transcriptomic profiles to explore molecular underpinnings.
Main Results:
- MDD patients exhibited altered FCs in the left hippocampus tail with prefrontal cortex and temporal/visual cortices.
- These abnormal FCs normalized after ECT treatment.
- Functional disruptions in MDD were associated with synaptic signaling, ion transport, cell-cell signaling, and neurogenesis.
Conclusions:
- This study provides novel insights into the functional connectome disruption of individual hippocampal subregions in MDD.
- It offers initial evidence for the molecular basis of these functional impairments.
Background:
The hippocampus has been widely reported to be involved in the neuropathology of major depressive disorder (MDD). All the previous researches adopted group-level hippocampus subregions atlas to investigate abnormal functional connectivities in MDD in absence of capturing individual variability. In addition, the molecular basis of functional impairments of hippocampal subregions in MDD remains elusive.
Objective:
We aimed to reveal functional disruptions and recovery of individual hippocampal subregions in MDD patients before and after ECT and linked these functional connectivity differences to transcriptomic profiles to reveal molecular mechanism.
Methods:
we used group guided individual functional parcellation approach to define individual subregions of hippocampus for each participant. Resting-state functional connectivity (FC) analysis of individual hippocampal subregions was conducted to investigate functional disruptions and recovery in MDD patients before and after ECT. Spatial association between functional connectivity differences and transcriptomic profiles was employed to reveal molecular mechanism.
Results:
MDD patients showed increased FCs of the left tail part of hippocampus with dorsolateral prefrontal cortex and middle temporal gyrus while decreased FC with primary visual cortex. These abnormal FCs in MDD patients were normalized after ECT. In addition, we found that functional disruptions of the left tail part of hippocampus in MDD were mainly related to synaptic signaling and transmission, ion transport, cell-cell signaling and neurogenesis.
Conclusion:
Our findings provide initial evidence for functional connectome disruption of individual hippocampal subregions and their molecular basis in MDD.
