A causal and dissociable role for the right inferior frontal gyrus 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 of the rIFG increased ratings of physical pain but decreased ratings of social pain, suggesting distinct roles in empathic processing for these two pain types. However, the nonspecific response to physical images indicates that the effect may reflect enhanced attentional capture rather than empathy per se. In contrast, dmPFC stimulation did not modulate ratings, potentially reflecting its role in higher-order social cognitive processes rather than affective empathy. These results provide causal evidence for the rIFG's role in shaping responses to others' pain, with effects differing across pain types. While some of these effects may reflect enhanced salience or attentional capture rather than empathy alone, the findings nonetheless support the idea that distinct neural processes contribute to empathy for social versus physical pain.