Reduced reward-related neural response to mimicry in individuals with autism

Mimicry is a facilitator of social bonds in humans, from infancy. This facilitation is made possible through changing the rewardvalue of social stimuli; for example, we like and affiliate more with people who mimic us. Autism spectrum disorders (ASD) aremarked by difficulties in forming social bonds. In this study, we investigate whether the reward-related neural response to beingmimicked is altered in individuals with ASD, using a simple conditioning paradigm. Multiple studies in humans and nonhuman pri-mates have established a crucial role for the ventral striatal (VS) region in responding to rewards. In this study, adults with ASDand matched controls first underwent a conditioning task outside the scanner, where they were mimicked by one face and‘anti-mimicked’ by another. In the second part, participants passively viewed the conditioned faces in a 3T MRI scanner using amulti-echo sequence. The differential neural response towards mimicking vs. anti-mimicking faces in the VS was tested for groupdifferences as well as an association with self-reported autistic traits. Multiple regression analysis revealed lower left VS responseto mimicry (mimicking > anti-mimicking faces) in the ASD group compared to controls. The VS response to mimicry was nega-tively correlated with autistic traits across the whole sample. Our results suggest that for individuals with ASD and high autistictraits, being mimicked is associated with lower reward-related neural response. This result points to a potential mechanism under-lying the difficulties reported by many of individuals with ASD in building social rapport.