Disgust processing differences and their neural correlates in autistic youth

While there is some data indicating increased pica behaviors in autism, disgust processing differences in autism (ASD) have been less explored. Here, we examined disgust processing behaviorally and neurally in autistic youth. Participants (25 ASD; 24 typically developing [TD]; aged 8-17) completed disgust proneness measures and underwent fMRI scans while viewing pictures depicting physical disgust (disgusting food), or social vicarious disgust (disgust facial expressions). Behaviorally, the ASD group reported significantly higher disgust proneness compared to the TD group. Neurally, during physical disgust conditions, the ASD group versus the TD group showed significantly less activity in emotion-related regions (anterior [AI] and mid-insula [MI], amygdala, ventromedial prefrontal cortex [vmPFC], medial orbitofrontal cortex [mOFC]) and more activity in the posterior insula (PI). During social disgust conditions, the ASD group showed significantly more activity in the amygdala, AI, anterior cingulate, vmPFC/mOFC, and less activity in the MI, PI, and fusiform areas. Across participants, right MI and bilateral mOFC activity was associated with disgust processing and connectivity patterns during both conditions were significantly correlated with individual differences in disgust proneness. Altogether, these results indicate that the ASD group has increased disgust proneness and differences in numerous emotion-related brain regions when visually processing disgust. Further, differences in disgust processing may result from MI and mOFC activity and connectivity differences.