Modulatory effects of ketamine on EEG source-based resting state connectivity in treatment resistant depression.
Translational psychiatry March 6, 2026 Ty Lees, Jason N Scott, Brian W Boyle et al.
A single low dose of ketamine (0.5 mg/kg) reduced depressive, anhedonic, and ruminative symptoms 24 hours later in 24 people with treatment-resistant depression. The symptom improvement was not linked to changes in brain connectivity but was associated with connectivity patterns present before the infusion. After ketamine, participants showed broad increases in resting-state functional connectivity within and between the default mode and frontoparietal networks, as measured by EEG. The authors suggest these connectivity increases may reflect ketamine's synaptogenic effects, which can be short-lived. The study included 34 healthy controls who did not receive ketamine.