Postictal resting-state connectivity changes after electroconvulsive therapy-induced seizures

Electroconvulsive therapy (ECT) leads to temporary changes of brain function. It is unclear what changes take place shortly after the induced seizures. Here, we present the first human study on resting-state network (RSN) changes in the immediate postictal state. The objective was to investigate brain-wide RSNs connectivity changes shortly after ECT-induced seizures. We analyzed prospectively collected resting-state functional magnetic resonance imaging scans from 17 patients with major depression at baseline and one hour after ECT-sessions. RSNs were extracted and changes in mean and voxel-wise RSN connectivity strength were calculated. Data were compared to 27 age, sex, and level of education matched healthy individuals to account for test-retest effects. Clinical postictal recovery was measured using the reorientation time questionnaire. Group by time interaction analyses showed postictal decreases in mean connectivity strength in the left central executive network and the auditory network in patients, compared to retest in healthy controls (β = - 0.18 [CrI95 - 0.27, - 0.09] and (β = - 0.22 [CrI95 - 0.36, - 0.07], respectively). Voxel-wise analyses revealed increased between-network connectivity in the salience network with cerebellar regions compared to healthy controls, along with decreased within-network connectivity in the default mode network and left central executive network. No significant associations with clinical recovery or other variables were observed. In this cohort, ECT-induced seizures were followed by postictal decreases of connectivity strength in the left central executive network and the auditory network and increase of connectivity between the salience network and cerebellum. Postictal network changes were not associated with clinical postictal recovery.Clinical trial registration: ClinicalTrials.gov NCT04028596.