Somatic and vicarious pain are represented by dissociable multivariate brain patterns

TLDR

Understanding how humans represent others’ pain is critical for pro‑social behavior, yet while shared‑experience theories posit common brain representations for somatic and vicarious pain, evidence indicates specialized circuits are required to experience others’ suffering. Multivariate pattern analyses of fMRI data revealed distinct, highly accurate brain patterns for somatic and vicarious pain that were mutually exclusive, somatotopically organized, generalize across pain modalities, and provide specific neural targets for studying pain empathy.

Abstract

Understanding how humans represent others’ pain is critical for understanding pro-social behavior. ‘Shared experience’ theories propose common brain representations for somatic and vicarious pain, but other evidence suggests that specialized circuits are required to experience others’ suffering. Combining functional neuroimaging with multivariate pattern analyses, we identified dissociable patterns that predicted somatic (high versus low: 100%) and vicarious (high versus low: 100%) pain intensity in out-of-sample individuals. Critically, each pattern was at chance in predicting the other experience, demonstrating separate modifiability of both patterns. Somatotopy (upper versus lower limb: 93% accuracy for both conditions) was also distinct, located in somatosensory versus mentalizing-related circuits for somatic and vicarious pain, respectively. Two additional studies demonstrated the generalizability of the somatic pain pattern (which was originally developed on thermal pain) to mechanical and electrical pain, and also demonstrated the replicability of the somatic/vicarious dissociation. These findings suggest possible mechanisms underlying limitations in feeling others’ pain, and present new, more specific, brain targets for studying pain empathy.