Combined virtual reality social cognition training and theta transcranial alternating current stimulation: A proof-of-concept study in healthy controls.

Social cognition, particularly theory of mind (ToM) is important for understanding and engaging with the social environment. The continual development and improvement of these skills can be of broad benefit. However, current social cognitive training methods are time intensive and have limited ecological validity. Virtual reality (VR) combined with transcranial alternating current stimulation (tACS) may provide a more ecologically valid and efficient alternative. The current study investigated the effects of theta tACS to the right temporoparietal junction (rTPJ) on VR social cognition training in a group of 21 healthy adults. Outcome measures were behavioural (attribution of intentions ToM task) and neurophysiological (spectral power and event related potentials). Participants completed two identical lab sessions each. One session included VR training concurrent with active theta tACS and the other, with sham theta tACS. Participants completed resting state electroencephalography (EEG) and ToM tasks with concurrent EEG pre and post VR-tACS in each session. tACS condition was randomised and all assessments were double-blinded. VR and active tACS, but not VR and sham tACS, improved ToM task accuracy. ToM task response times improved pre versus post VR-tACS regardless of tACS condition (active vs sham). Resting state theta power increased significantly across the cortex post VR-tACS regardless of tACS condition. This study provides the first evidence for the feasibility of a combined VR-tACS protocol for social cognition. Future research in larger samples, and with multiple sessions, in both healthy and clinical populations are recommended.