Cortical oscillatory mechanisms supporting the control of human social-emotional actions

The human anterior prefrontal cortex (aPFC) is involved in regulating social-emotional behavior, presumably by modulating effective connectivity with down-stream parietal, limbic, and motor cortices. Regulating that connectivity might rely on theta-band oscillations (4-8 Hz), a brain rhythm known to create overlapping periods of excitability between distant regions by temporally releasing neurons from inhibition. Here, we use magnetoencephalography (MEG) to understand how aPFC theta-band oscillations implement control over prepotent social-emotional behaviors, i.e. the control over automatically elicited approach and avoidance actions.Forty human male participants performed a social approach-avoidance task, in which they approached or avoided visually displayed emotional faces (happy or angry) by pulling or pushing a joystick. Approaching angry and avoiding happy faces (incongruent condition) requires rapid application of cognitive control to override prepotent habitual action tendencies to approach appetitive and to avoid aversive situations. In the time window prior to response delivery, trial-by-trial variations in aPFC theta-band power (6 Hz) predicted reaction time increases during emotional control, and were inversely related to beta-band power (14-22 Hz) over parieto-frontal cortex. In sensorimotor areas contralateral to the moving hand, pre-movement gamma-band rhythms (60-90 Hz) were stronger during incongruent than congruent trials, with power increases phase-locked to peaks of the aPFC theta-band oscillations.These findings define a mechanistic relation between cortical areas involved in implementing rapid control over human social-emotional behavior. The aPFC may bias neural processing towards rule-driven actions and away from automatic emotional tendencies by coordinating tonic disinhibition and phasic enhancement of parieto-frontal circuits involved in action selection