Surface-based functional brain imaging analysis of major depressive disorder after electroconvulsive therapy

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• The precise neural mechanisms of electroconvulsive therapy (ECT) for major depressive disorder (MDD) are not fully understood.
• Previous neuroimaging studies using voxel-based methods have limitations in spatial localization compared to surface-based approaches.

Purpose of the Study:

• To investigate the antidepressant mechanisms of ECT using advanced surface-based neuroimaging analyses.
• To identify potential neuroimaging markers for predicting ECT efficacy in MDD patients.

Main Methods:

• Longitudinal resting-state functional magnetic resonance imaging (rs-fMRI) was conducted on 46 MDD patients undergoing ECT.
• Surface-based analyses examined alterations in amplitude of low-frequency fluctuations (ALFF) and functional connectivity.
• Correlation and support vector regression (SVR) analyses explored relationships between brain activity, connectivity, and treatment outcomes, with validation in a separate cohort.

Main Results:

• ECT treatment led to increased ALFF in the left dorsolateral prefrontal cortex, orbitofrontal cortex (OFC), and inferior frontal cortex (IFC).
• Significant increases in functional connectivity were observed within the default mode network (DMN) and between the frontoparietal and DMN.
• Higher IFC-OFC functional connectivity correlated with depression remission, and baseline connectivity predicted symptom improvement, findings validated in an independent cohort.

Conclusions:

• Surface-based analysis provides novel insights into the antidepressant effects of ECT.
• Specific patterns of functional connectivity, particularly involving the IFC and OFC, may serve as predictive biomarkers for ECT response in MDD.