Decoding affect in emotional body language: valence representation in the action observation network.

Humans are highly adept at inferring emotional states from body movements in social interactions. Nonetheless, it is under debate how this process is facilitated by neural activations across multiple brain regions. The specific contributions of various brain areas to the perception of valence in biological motion remain poorly understood, particularly those within the action observation network (AON) and those involved in processing emotional valence. This study explores which cortical regions involved in processing emotional body language depicted by kinematic stimuli contain valence information, and whether this is reflected either in the magnitude of activation or in distinct activation patterns. Results showed that neural patterns within the AON, notably the inferior parietal lobule (IPL), exhibit a neural geometry that reflects the valence impressions of the observed stimuli. However, the representational geometry of valence-sensitive areas mirrors these impressions to a lesser degree. Our findings also reveal that the activation magnitude in both AON and valence-sensitive regions does not correlate with the perceived valence of emotional interactions. Results underscore the critical role of the AON, particularly the IPL, in interpreting the valence of emotional interactions, indicating its essential function in the perception of valence, especially when observing biological movements.