A reduced ability to discriminate social from non-social touch at the circuit level may underlie social avoidance in autism.

Scientists studied how mouse brains process different types of touch - social touch from other mice versus touching objects. Normal mice preferred social interactions and their brains could tell the difference between the two types of touch. Mice with autism-like traits avoided both social and non-social touch equally and their brains had trouble distinguishing between them. This suggests that difficulties processing social touch in the brain might explain why some autistic people avoid social contact.

This preclinical study used advanced neural recording techniques to investigate touch processing differences in a mouse model of autism (Fmr1 knockout mice). Researchers recorded neural activity in brain regions involved in touch processing while mice interacted with social (other mice) and non-social (objects) stimuli. Wild-type mice showed typical social preferences and neural discrimination between social and non-social touch. In contrast, the autism mouse model showed equal aversion to both social and non-social interactions, particularly at close proximity.

Importantly, their brain circuits showed reduced ability to distinguish between social and non-social touch contexts. The findings suggest that impaired neural processing of social touch may contribute to social avoidance behaviors observed in autism.

These findings provide neurobiological insights into touch sensitivities and social avoidance in autism. Understanding these brain circuit differences could inform development of targeted interventions for sensory processing difficulties and social engagement challenges in autism.

This is a preclinical study using mouse models, so findings may not directly translate to humans. Sample sizes are not reported. The study uses one specific autism model (Fmr1 knockout) which may not represent all forms of autism.

Social touch is critical for communication to impart emotions and intentions. However, certain autistic individuals experience aversion to social touch. Here, we used Neuropixels probes to record neural responses to social vs. non-social interactions in somatosensory cortex, tail of striatum, and basolateral amygdala. We find that wild type mice show aversion to repeated presentations of an inanimate object but not of another mouse.

Cortical neurons are modulated especially by touch context (social vs. object), while striatal neurons change their preference depending on whether mice could choose or not to interact. In contrast, Fmr1 knockout (KO) mice, a model of autism, find social and non-social interactions equally aversive, especially at close proximity, and their cortical/striatal neurons are less able to discriminate social valence. A linear model shows that the encoding of certain avoidance/aversive behaviors in cortical neuron activity differed between genotypes. Thus, a reduced capacity to represent social stimuli at the circuit level may underlie social avoidance in autism.