In-phase and anti-phase dual-site beta tACS differentially influence functional connectivity and motor inhibition

In this study, we employed dual-site transcranial alternating current stimulation (tACS) targeting the right inferior frontal gyrus (rIFG) and primary motor cortex (M1) to directly manipulate phase relationships in the beta band and assess their effects on both functional connectivity and motor inhibition.

Fifty-two healthy participants received in-phase, anti-phase and sham stimulation while performing a stop-signal task. The results revealed that connectivity between rIFG and lM1 increased following in-phase but decreased after anti-phase stimulation. Although no direct modulation of task performance was observed, the greater connectivity increase between the targets during in-phase stimulation was predictive of faster inhibitory performance.