Neural correlates of inhibition of socially relevant stimuli in adults with autism spectrum disorder.

Adults with autism spectrum disorder (ASD) can demonstrate difficulties with inhibiting inappropriate social responses. Presently, little research has utilized socially relevant stimuli to explore the modulatory effects of emotion on cognitive control in this population. To assess neural mechanisms of inhibiting social stimuli, we presented images of happy or sad facial expressions in a Go/NoGo task to unmedicated adults with ASD and to controls during functional magnetic resonance imaging (fMRI). Groups did not differ on behavioral measures. Brain activation in response to NoGo vs. Go trials revealed differing regional patterns of activation within groups. Controls recruited brain regions involved in inhibition (dorsal- [DLPFC] and ventro-lateral prefrontal cortices [VLPFC], anterior cingulate cortex [ACC]), response suppression (parietal lobe), interoceptive awareness (insula), and also the fusiform and middle temporal gyri. Adults with ASD only recruited the VLPFC and right fusiform gyrus, and weakly activated the ACC and insula. Between-group comparisons indicated that controls activated the DLPFC, while adults with ASD relied on the VLPFC and the fusiform gyrus to inhibit responses. Adults with ASD may have relied more on visual association cortex, possibly as a means of recruiting additional neural processes that could act as a compensatory mechanism.