Modulation of interhemispheric functional coordination in electroconvulsive therapy for depression

Abstract

Considerable evidence suggests that depression is related to interhemispheric functional coordination deficits. For depression, electroconvulsive therapy (ECT) is the most rapid and effective therapy, but its underlying mechanism remains unknown. The aim of this study was to explore the impact of ECT on the interhemispheric functional coordination in depression patients. We used resting-state functional magnetic resonance imaging to observe the change of interhemispheric functional coordination with the method of voxel-mirrored homotopic connectivity (VMHC) in 11 depressed patients before and after ECT, compared with 15 healthy controls. The results showed that, compared with depression patients before ECT, VMHC was significantly increased in superior frontal gyri (BA 8), middle frontal gyri (two clusters: BA 8/9 and BA 10) and angular gyri (BA 39) in depression patients after ECT. Compared with healthy controls, VMHC in those areas was significantly lower in the middle frontal gyri (BA 8/9) and angular gyri (BA 39) in depression patients before ECT, but no significant difference was observed in the superior frontal gyri (BA 8) and middle frontal gyri (BA 10). There was no significant correlation between the changes of Hamilton Depression Rating Scale scores and changed VMHC values in those four areas in depression patients. The results suggest that ECT selectively modulated interhemispheric functional coordination in depression patients. Such may play an important mechanistic role in the treatment of depression, and may afford a useful avenue for optimizing treatment.

Modulation of Intrinsic Brain Activity by Electroconvulsive Therapy in Major Depression

“…Previous studies have reported ECT-related changes in RSFC in dorsolateral PFC (19; 20). In the current study, we identified ΔMD effects in dorsolateral PFC in partial conjunction analyses; however, dorsolateral PFC did not exhibit ΔECT effects, meaning that RSFC did not change on average across all patients in this region.…”

“…Therefore, brain networks affected by ECT-induced seizures in all patients may differ or only partially overlap with networks supporting improved depressive symptoms in patients that respond to ECT. To date, very few neuroimaging studies address the contributions of ECT-induced seizures and symptom improvement to structural or functional neuroplasticity, relying instead on post hoc analyses of symptoms in regions already showing ECT effects (11; 18), or restricting analyses to treatment responders (12; 19; 20). Therefore, some ECT-related effects reported previously may not underlie clinical outcome, but instead reflect nonspecific physiological effects of ECT unrelated to depressive symptoms.…”

Electroconvulsive Therapy Modulates the Structural and Functional Architecture of Frontal Pole in Major Depressive Disorder

“…The left ANG was reported to be involved in MDD patients such as decreased regional cerebral blood flow [38], decreased amplitude of lowfrequency fluctuation, and increased fractional amplitude of low-frequency fluctuation [39]. In a previous study, Wei and his colleagues also identified significantly increased voxelmirrored homotopic connectivity in the ANG, which indicated that the rebalance of ANG may contribute to the therapeutic mechanism of ECT for depression [7]. Our finding was consistent with the previous study highlighting the important role of the left but not the right ANG.…”

“…During each ECT procedure, patients were under propofol anesthesia. We administered succinylcholine and atropine to relax muscles and suppress the secretion of glands, and monitored seizure activity with electroencephalography [7]. Detailed information can be found in the paper by Wei, et al [7].…”

“…Indeed, cognitive changes, especially the retrograde and anterograde memory deficits, have been widely reported due to ECT [4]. Although several previous studies were performed to uncover the mechanism of the ECT in the MDD patients [5][6][7], the mechanism underlying the therapeutic efficacy and side effects of ECT in MDD patients is still under debate, which hinders the optimization of ECT procedures for improving therapeutic efficacy and reducing side effects.…”