Neural correlates of emotional inhibitory control in autism spectrum disorders.

Atypical inhibitory function is often present in individuals with autism spectrum disorder (ASD), who may have difficulty suppressing context-inappropriate behaviors. We investigated the neural correlates of inhibition in ASD in response to both emotional and non-emotional stimuli using an fMRI Go/NoGo inhibition task with human faces and letters. We also related neural activation to behavioral dysfunction in ASD. Our sample consisted of 19 individuals with ASD (mean age=25.84) and 22 typically developing (TD) control participants (mean age=29.03). As expected, no group differences in task performance (inhibition accuracy and response time) were found. However, adults with ASD exhibited greater angular gyrus activation in face response inhibition blocks, as well as greater fusiform gyrus activation than controls, in a condition comparing face inhibition to letter inhibition. In contrast, control participants yielded significantly greater anterior cingulate cortex (ACC) activation in letter inhibition blocks. A positive relationship between communication and language impairment and angular gyrus activation during face inhibition was also found. Group activation differences during inhibition tasks in the context of comparable task performance and the relationship between activation and dysfunction highlight brain regions that may be related to ASD-specific dysfunction.