Oxytocin administration tentatively modulates EEG markers of social and cognitive neural activity

Electroencephalography (EEG) is a cost-effective method with excellent temporal precision for investigating neural mechanisms underlying social and cognitive processes. Oxytocin is a neuropeptide known to influence these behaviors, but prior EEG studies evaluating its electrophysiological effects have yielded mixed results. This heterogeneity, likely due to variations in EEG measures, study designs, dosages, and participant samples, necessitates a comprehensive synthesis to clarify oxytocin's neural impact.

Researchers conducted two multilevel random effects meta-analyses to synthesize existing data on oxytocin's effects on EEG measures. The first meta-analysis focused on neural correlates of social and cognitive processing, while the second examined exploratory, less task-specific neural activity, such as microstate modulation. They synthesized 161 effect sizes from 28 randomized controlled trials, encompassing a total of 1361 participants from diverse population groups, comparing oxytocin administration against placebo controls.

The multilevel meta-analyses revealed statistically significant, albeit small, effect sizes for oxytocin administration across various EEG measures. For social and cognitive processes, the effect size was Hedges' g = 0.14, with significant heterogeneity (p < 0.01). For exploratory neural activity, the effect size was Hedges' g = 0.28, also showing significant heterogeneity (p < 0.001).

Moderator analyses indicated that different EEG measurements of interest (e.g., event-related potentials) and the proportion of female participants significantly moderated oxytocin's effect on neural EEG activity. These findings provide tentative evidence that oxytocin modulates a broad spectrum of EEG-based markers of neural activity.