Perceptual and Neural Response to Affective Tactile Texture Stimulation in Adults with Autism Spectrum Disorders

<jats:p>Autism spectrum disorders (<jats:styled-content style="fixed-case">ASD</jats:styled-content>) are associated with differences in sensory sensitivity and affective response to sensory stimuli, the neural basis of which is still largely unknown. We used psychophysics and functional magnetic resonance imaging (<jats:styled-content style="fixed-case">fMRI</jats:styled-content>) to investigate responses to somatosensory stimulation with three textured surfaces that spanned a range of roughness and pleasantness in a sample of adults with <jats:styled-content style="fixed-case">ASD</jats:styled-content> and a control group. While psychophysical ratings of roughness and pleasantness were largely similar across the two groups, the <jats:styled-content style="fixed-case">ASD</jats:styled-content> group gave pleasant and unpleasant textures more extreme average ratings than did controls. In addition, their ratings for a neutral texture were more variable than controls, indicating they are less consistent in evaluating a stimulus that is affectively ambiguous. Changes in brain blood oxygenation level‐dependent (<jats:styled-content style="fixed-case">BOLD</jats:styled-content>) signal in response to stimulation with these textures differed substantially between the groups, with the <jats:styled-content style="fixed-case">ASD</jats:styled-content> group exhibiting diminished responses compared to the control group, particularly for pleasant and neutral textures. For the most unpleasant texture, the <jats:styled-content style="fixed-case">ASD</jats:styled-content> group exhibited greater <jats:styled-content style="fixed-case">BOLD</jats:styled-content> response than controls in affective somatosensory processing areas such as the posterior cingulate cortex and the insula. The amplitude of response in the insula in response to the unpleasant texture was positively correlated with social impairment as measured by the Autism Diagnostic Interview‐Revised (<jats:styled-content style="fixed-case">ADI‐R</jats:styled-content>). These results suggest that people with <jats:styled-content style="fixed-case">ASD</jats:styled-content> tend to show diminished response to pleasant and neutral stimuli, and exaggerated limbic responses to unpleasant stimuli, which may contribute to diminished social reward associated with touch, perpetuating social withdrawal, and aberrant social development. <jats:italic><jats:bold>Autism Res</jats:bold> 2012,5:231–244</jats:italic>. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.</jats:p>