The majority of children with autism spectrum disorders (ASD) experience some form of sensitivity to sensory stimuli, but how exactly is that manifested in the brain? Researchers from the University of California Los Angeles examined the reactions of children with ASD to auditory and visual stimuli and monitored their brains’ reactions. They found that children with ASD were more responsive to sensory stimuli, especially in areas of the brain that manage sensory and emotional processing.

Using fMRI scans, the researchers observed the response of 25 children with ASD and 25 age- and IQ-matched typically developing children. Both sets of children were exposed to mildly irritating sounds like white noise, visuals like rotating spirals of color, or a combination of auditory and visual stimuli. The fMRI was able to detect changes in blood flow as the children’s brains responded. In addition to the fMRI, the participants’ parents completed three questionnaires. The Sensory Overresponsitivity Inventory and Short Sensory Profile were used to identify atypical sensory responses and the Child Behavior Checklist helped the researchers inventory the children’s problem behaviors.

The brains of the children with ASD responded more strongly to the sensory stimuli than those of their neurotypical peers. The amygdala, hippocampus, and prefrontal cortex—related to processing emotions—all exhibited heightened responses. The visual cortex and thalamus, which process sensory information, also produced a stronger response. Finally, the researchers found that elevated fMRI responses to stimuli may correlate with sensory sensitivity, but are not associated with anxiety.

The results suggest that sensory overresponsitivity may affect emotional regulation in addition to the sensory processing regions of the brain.

This research is published in the Journal of the American Academy of Child and Adolescent Psychiatry and is available on PubMed.

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