Autistic traits modulate neural responses to social signals during natural vision.

Differences in social perception, a hallmark of autism spectrum disorder (ASD), are also evident at subclinical levels in the general population. However, it remains unclear how such variation in autistic traits relate to neural processing of different types of social information. Here, we investigated whether autistic traits in neurotypical individuals are associated with neural responses to a broad array of social perceptual features during watching naturalistic stimuli using functional magnetic resonance imaging (fMRI). We also tested the generalizability of these effects across two experiments. Ninety-seven participants completed the Autism Spectrum Quotient (AQ) and watched a set of 96 movie clips and a full movie during an fMRI scan. Intensity of 126 social features in the movie stimuli was continuously annotated by independent observers, and 44 most reliably rated features were used to model neural responses. We examined how consistently the responses to each social feature were dependent on the participants' AQ scores. Replicable AQ-dependent neural responses to social features were found in both datasets. The temporal cortex and especially the superior temporal gyrus (STG), served as a central "hub" where autistic traits were consistently associated with neural responses to social features across datasets. Different AQ subscales also revealed distinct association patterns in other brain regions. These findings indicate how autism-related traits broadly relate to neural processing of naturalistic social signals, providing neurobiological evidence for the heterogeneous nature of autism-related traits.