Social avoidance is a hallmark of social anxiety disorder. Difficulties in controlling avoidance behavior are the core maintaining factor of this impairing condition, hampering the efficacy of existing therapies. This preregistered study tested a physiologically-grounded non-invasive enhancement of control over social approach and avoidance behavior in socially anxious individuals. Participants received dual-site phase-coupled electrical stimulation aimed at enhancing endogenous inter-regional theta-gamma phase-amplitude coupling between prefrontal and sensorimotor cortex, a mechanism known to support emotional-action control in non-anxious individuals. We measured behavioral and fMRI-BOLD responses during in-phase, anti-phase, and sham stimulations, while participants of either sex performed a social approach-avoidance task, involving either automatic or controlled emotional actions. In-phase stimulation selectively enhanced control over approach-avoidance actions. Notably, in-phase stimulation modulated neural responses in the same prefrontal region where target engagement increased as a function of trait anxiety. These findings illustrate how human neurophysiological connectivity can be leveraged to improve control over social avoidance, opening the way for mechanistically grounded clinical interventions of persistent avoidance in anxiety disorders. Significance statement Controlling automatic approach-avoid behavior is essential for human social interactions. This ability is impaired in social anxiety, and recent evidence suggests that neurotypical brains use endogenous rhythmic coupling for social emotion control. In a preregistered study, we used noninvasive electrical brain stimulation to enhance endogenous rhythmic coupling between prefrontal theta- and sensorimotor gamma-band rhythms, while highly socially anxious individuals solved an emotional control challenge. In-phase stimulation selectively enhanced emotional action control and modulated neural activity in a prefrontal cortex region where brain stimulation reactivity increased as a function of trait anxiety. These findings provide evidence for the clinical potential of this interventional approach to social anxiety.
Meijer et al. (Thu,) studied this question.