Dissociated Neural Representations of Pain Expressions of Different Races

To investigate whether coding pain expressions of own-race and other-race individuals engages overlapping or distinct neuronal populations, we recorded event-related brain potentials from Chinese and Caucasian adults when viewing an adaptor face (with pain or neutral expressions) and a target face (with only pain expression) presented in rapid succession. If distinct neuronal populations are engaged in coding pain expressions of different races, repetition suppression (RS) of neural activity to pain expressions, that is, decreased neural responses to target faces preceded by pain versus neutral adaptors, should occur when an adaptor and a target are of the same race but not when they are of different races. We found that neural responses to adaptor faces at 128-188 ms (P2) and 200-300 ms (N2) over the frontal/central areas were positively shifted by pain versus neutral expressions. Moreover, RS of neural responses to target faces in the P2/N2 windows occurred when an adaptor and a target were of the same race but not when their racial identities differed, and these effects were observed in both Chinese and Caucasian participants. Our results suggest that perception of pain expressions of different races may recruit distinct neuronal assemblies at a specific stage of the processing stream.