Beyond Cognition: Action Simulation Regulates Vicarious Pain Perception Through an Embodied Neural Pathway.

Although cognitive reappraisal is known to regulate pain-related affect, it remains unclear whether vicarious pain perception can also be modulated through behavior-oriented embodied processes. Using fMRI, we compared cognitive reappraisal and action simulation during vicarious pain in a within-subject design. Thirty-one participants completed a vicarious pain regulation task under three conditions: watch, cognitive reappraisal, and action simulation. Behaviorally, both strategies reduced vicarious pain ratings, with cognitive reappraisal producing stronger regulation but longer response times, indicating greater cognitive demands. Neuroimaging analyses revealed a shared regulatory network involving the dorsomedial prefrontal cortex (dmPFC), inferior parietal lobule (IPL), and anterior insula (AI). However, effective connectivity analyses using dynamic causal modeling (DCM) revealed strategy-specific pathways: cognitive reappraisal enhanced IPL-AI coupling while reducing dmPFC-IPL connectivity, suggesting a top-down cognitive control route. In contrast, action simulation primarily increased IPL-AI coupling. Generalized psychophysiological interaction (gPPI) analyses further showed that action simulation strengthened task-dependent functional coupling between the left dmPFC and postcentral gyrus, which was associated with faster regulatory responses, suggesting reliance on an embodied sensorimotor pathway. Additionally, the IPL showed differential lateralization: the left IPL predicted regulation success in cognitive reappraisal, whereas the right IPL was more engaged in action simulation. These findings support a dual-pathway account of pain-empathy regulation, in which action simulation provides a less cognitively demanding route for modulating vicarious pain responses alongside cognitive control, which may inform low-burden strategies for managing such responses in clinical contexts. PERSPECTIVE: Using fMRI with DCM and gPPI analyses, this study suggests that action simulation provides an embodied route for regulating vicarious pain perception, distinct from cognitively demanding reappraisal. These findings extend cognitive accounts of empathy regulation and underscore sensorimotor mechanisms supporting rapid responses to others' pain.