Interpersonal Brain Synchronization in Social Pain Contexts: An fNIRS-Based Exploration of Empathy.

Social pain is a common occurrence in interpersonal interactions, yet limited research has explored the neural mechanisms underlying both social pain and social pain empathy. Existing studies often focus on the neural processes of individuals experiencing pain, referred to as "subjects," or those empathizing with them, known as "observers." This study examines the neural mechanisms involved in the process of social pain empathy from the perspective of interpersonal brain synchronization (IBS). To do so, we employed functional near-infrared spectroscopy (fNIRS) to simultaneously scan the brains of both subjects and observers in social pain scenarios created using the Cyberball paradigm. The study's findings indicate that in social pain contexts, the IBS among dyads composed of subjects and observers was significantly enhanced in the dorsolateral prefrontal cortex (dlPFC) compared to non-social pain contexts. This brain region is associated with emotion regulation. Furthermore, we found that this enhancement depended on the observers' levels of rejection sensitivity. This study provides the inaugural exploration into the neural mechanisms underlying social pain empathy through the lens of IBS.