Network localization of brain structural and functional alterations induced by electroconvulsive therapy for depression

Extensive longitudinal neuroimaging research has investigated brain structural and functional changes following electroconvulsive therapy (ECT) for depression. However, neither the regional nor the global brain effects reported in previous research can satisfactorily explain all aspects of the antidepressant efficacy of ECT, pointing to a potentially more refined network-specific mechanism. We initially identified the locations of brain structural and functional alterations induced by ECT for depression from 34 published studies, including 15 voxel-based morphometry studies with 596 depressed individuals and 19 resting-state functional magnetic resonance imaging studies with 436 depressed individuals. By combining these affected brain locations with large-scale brain functional connectome datasets (1113 healthy and 255 clinical individuals), we then adopted a novel functional connectivity network mapping approach to construct ECT-modulated structural and functional alteration networks. Our data showed different and specific ECT-modulated structural and functional alteration networks, with the former predominantly involving the subcortical (hippocampus and amygdala), ventral attention (insula and operculum and temporoparietal junction) and somatomotor (precentral and postcentral gyrus) networks, while the latter mainly implicating the default network (medial prefrontal cortex and posterior cingulate cortex). These findings may not only reconcile prior discrepancy between the ECT-induced regional and global brain changes from a network perspective, but also suggest a dissociation between the brain structural and functional effects of ECT.