Abstract
Autism spectrum disorder (ASD) is a neuro-developmental disorder characterized by socio-emotional impairment, but the neural substrate is unknown. One characteristic of ASD is the lack of empathy and emotional engagement with others. Individuals with ASD have difficulty in relating others and recognizing their emotions when other people demonstrate angry, happy or sad feeling. This study aimed at investigating brain activity during perception of facial expression using functional MRI (fMRI) . Thirteen subjects who were diagnosed as ASD according to DSM-IV-TR and 13 age-matched healthy controls were examined. The subjects were watching photographs with happy, sad, angry and neutral facial expression. BOLD signals were obtained during these visual stimuli with GRE-EPI T2* imaging. Region of Interest (ROI) was determined with MarsBar, and comparison was made between the activity in ASD and controls regarding each facial expression with ANOVA. ASD group showed significantly reduced activity in right fusiform gyrus and right mirror neuron system (rMNS) in the frontal cortex. Interaction with facial expression was shown in rMNS. Autism spectrum quotient (AQ) values in ASD subjects were significantly correlated with hypoactivity of rMNs. These results suggest that the disturbance of MNS in the frontal cortex involves in the impairment in perception of facial expression in ASD subjects.
