Functional reorganization of intra‐ and internetwork connectivity in major depressive disorder after electroconvulsive therapy

Abstract

Electroconvulsive therapy (ECT) is an effective and rapid treatment for major depressive disorder (MDD). However, the neurobiological underpinnings of ECT are still largely unknown. Recent studies have identified dysregulated brain networks in MDD. Therefore, we hypothesized that ECT may improve MDD symptoms through reorganizing these networks. To test this hypothesis, we used resting-state functional connectivity to investigate changes to the intra- and internetwork architecture of five reproducible resting-state networks: the default mode network (DMN), dorsal attention network (DAN), executive control network (CON), salience network (SAL), and sensory-motor network. Twenty-three MDD patients were assessed before and after ECT, along with 25 sex-, age-, and education-matched healthy controls. At the network level, enhanced intranetwork connectivities were found in the CON in MDD patients after ECT. Furthermore, enhanced internetwork connectivities between the DMN and SAL, and between the CON and DMN, DAN, and SAL were also identified. At the nodal level, the posterior cingulate cortex had increased connections with the left posterior cerebellum, right posterior intraparietal sulcus (rpIPS), and right anterior prefrontal cortex. The rpIPS had increased connections with the medial PFC (mPFC) and left anterior cingulate cortex. The left lateral parietal had increased connections with the dorsal mPFC (dmPFC), left anterior prefrontal cortex, and right anterior cingulate cortex. The dmPFC had increased connection with the left anterolateral prefrontal cortex. Our findings indicate that enhanced interactions in intra- and internetworks may contribute to the ECT response in MDD patients. These findings provide novel and important insights into the neurobiological mechanisms underlying ECT.

Functional plasticity of the dorsomedial prefrontal cortex in depression reorganized by electroconvulsive therapy: Validation in two independent samples

“…For example, RS-fMRI findings have implicated decreased functional connectivity between the posterior default mode network and the central executive network (predominantly in the dorsolateral/dorsomedial prefrontal cortex) (Mulders et al, 2015). As an important addition to this work, findings from our previous study suggest that ECT increases the connectivity between the default mode network and the central executive network (Wang et al, 2018). This has been validated by another study that revealed enhanced connectivity between the dorsolateral prefrontal cortex and posterior default mode network following ECT (Abbott et al, 2013).…”

“…Consequently, ALFF is usually thought to reflect local spontaneous neural activity at rest (Zang et al, 2007). As an important addition to this work, findings from our previous study suggest that ECT increases the connectivity between the default mode network and the central executive network (Wang et al, 2018). In addition to being a localized summary measure, ALFF potentially impacts on functional connectivity (Cole, Yang, Murray, Repovs, & Anticevic, 2016).…”

Right inferior frontal gyrus: An integrative hub in tonal bilinguals

“…To further exclude head motion effects, “scrubbing” was employed to eliminate the bad images captured before two time points and after one time points, which exceeded the pre‐set criteria (frame displacement: FD, FD < 0.5) for excessive motion. Because previous studies have shown that global mean signal regression can lead to spurious resting‐state functional correlations and false inferences on the group level inference (Wang et al, ; Wang et al, ; Wang et al, ), thus, the global mean signal was not regressed during the preprocessing in our current study.…”

Effects of Electroconvulsive Therapy on Depression and Its Potential Mechanism

“…In addition, an enhanced feedforward cortical-subcortical connectivity from the fusiform face area to the amygdala was observed in MDD patients who underwent series ECT (Wang et al, 2017). Moreover, Wang et al (2018) demonstrated that ECT may contribute to enhanced interactions in the intra-and inter-networks in MDD patients that result in symptom alleviation. Employed with perfusion MRI, ECT contributed to hippocampal cerebral blood flow increases and declines in specific regions relevant to seizure physiology.…”

“…In short, according to the functional MRI studies mentioned above, ECT studies have brought renewed interest to the neuroplasticity of the brain, not only the hippocampus, but neural networks also showed more profound activity (Cao et al, 2018;Wang et al, 2018;Nuninga et al, 2019;Qiu et al, 2019).…”