A Causal and Dissociable Role for the Right Inferior Prefrontal Cortex in Empathy for Physical and Social Pain

The right inferior frontal gyrus (rIFG) and dorsomedial prefrontal cortex (dmPFC) are key nodes in the social brain, implicated in empathy for physical and social pain. However, their causal and dissociable contributions remain unclear. In this study, 52 young adults underwent focal transcranial direct current stimulation (f-tDCS) targeting the rIFG or dmPFC in a sham-controlled, double-blind, crossover design. Participants rated the intensity of pain in images depicting social or physical pain during stimulation. Anodal stimulation to the rIFG increased ratings of physical pain and decreased ratings of social pain, suggesting dissociable roles in processing empathy for these two pain types. In contrast, dmPFC stimulation did not modulate ratings, potentially reflecting its role in higher-order social cognitive processes rather than affective empathy. The effects of rIFG stimulation on social pain were significantly stronger in the initial trials, suggesting potential habituation within the rIFG or stimulation-specific effects. These results provide causal, dissociable evidence for the rIFG's involvement in empathy, with its effects differing based on the type of pain. This supports the proposal that distinct neural processes underlie empathy for social versus physical pain.