Modulating social feedback processing by deep TMS targeting the medial prefrontal cortex: Behavioral and electrophysiological manifestations.

Neuroimaging studies have suggested that the medial prefrontal cortex (mPFC) is a key brain region for social feedback processing, but previous findings are largely based on correlational approaches. In this study, we use the deep transcranial magnetic stimulation (dTMS) to manipulate mPFC activity, then investigate participants' behavioral performance and event-related potentials (ERPs) during the Social Judgment Paradigm. A between-subject design was applied, such that both the active dTMS group and the sham group consisted of 30 participants. We found that the sham group was more likely to predict that they would be socially accepted (rather than rejected) by peers, but the same was not true in the active group. Additionally, this study is the first one to observe ERP signal changes in response to dTMS manipulation. ERP results show that both the expectation stage and the experience stage of social feedback processing were modulated by dTMS: (1) at the expectation stage, the P1 component was smaller in the active group than the sham group, while the stimulus-preceding negativity showed a stronger differentiating effect between positive and negative prediction in the sham group than the active group; (2) at the experience stage, the sensitivity of the late positive potential to the valence and predictability of social feedback was stronger in the sham group than the active group. These results improve our understanding about the relationship between the mPFC and social feedback processing.