Pain modulates early sensory brain responses to task-irrelevant emotional faces

Pain can significantly impact our lives, and it has both cognitive and affective consequences for individuals. Nevertheless, our understanding of the effects of pain on social cognition remains limited. We investigated how pain affected the perception of facial emotions by recording brain responses to task-irrelevant faces in healthy participants. Event-related potentials (ERPs), which can reveal the time course of brain activity, were measured in response to neutral, sad, and happy faces prior to, during, and after a cold pressor pain. Early ERPs (P1, N170, and P2) reflecting early visual processing were analyzed. Pain significantly decreased the P1 amplitude to happy faces and increased the N170 amplitude to happy and sad faces compared to the pre-pain phase. The effect of pain on N170 was also observable in the post-pain phase. No effect of pain on face perception was found for the P2 component. These results suggest that pain alters feature and structure encoding of emotional faces even when they are task irrelevant. Further research is required to investigate how pain alters other aspects of social cognition, such as face perception in social interactions.