Improving emotional-action control by targeting long-range phase-amplitude neuronal coupling.

Control over emotional action tendencies is essential for every-day interactions. This cognitive function can fail during socially challenging situations, and is chronically attenuated in social psychopathologies such as social anxiety and aggression. Previous studies have shown that control over social-emotional action tendencies depends on phase-amplitude coupling between prefrontal theta-band (6 Hz) rhythmic activity and broadband gamma-band activity in sensorimotor areas. Here, we delivered dual-site phase-coupled brain stimulation to facilitate theta-gamma phase-amplitude coupling between frontal regions known to implement that form of control, while participants were challenged to control their automatic action tendencies in a social-emotional approach/avoidance-task. Participants had increased control over their emotional action tendencies, depending on the relative phase and dose of the intervention. Concurrently measured fMRI effects of task and stimulation, and estimated changes in effective connectivity, indicated that the intervention improved control by increasing the efficacy of anterior prefrontal inhibition over sensorimotor cortex. This enhancement of emotional action control provides causal evidence for a phase-amplitude coupling mechanism guiding action selection during emotional-action control. More generally, the finding illustrates the potential of physiologically-grounded interventions aimed at reducing neural noise in cerebral circuits where communication relies on phase-amplitude coupling.