Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder characterized by impaired social communication and restricted and repetitive behaviors (RRBs). Over the past decade, neuroimaging studies have provided considerable insights underlying neurobiological mechanisms of ASD. In this review, we introduce recent findings from brain imaging studies to characterize the brains of ASD across the human lifespan. Results of structural Magnetic Resonance Imaging (MRI) studies dealing with total brain volume, regional brain structure and cortical area are summarized. Using task-based functional MRI (fMRI), many studies have shown dysfunctional activation in critical areas of social communication and RRBs. We also describe several data to show abnormal connectivity in the ASD brains. Finally, we suggest the possible strategies to study ASD brains in the future.
Autistic Disorder* ; Brain* ; Child ; Autism Spectrum Disorder* ; Humans ; Magnetic Resonance Imaging ; Neuroimaging

PURPOSE: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication impairments and repetitive behaviors or restricted interests. Impaired pragmatic language comprehension is a universal feature in individuals with ASD. However, the underlying neural basis of pragmatic language is poorly understood. In the present study, we examined neural activation patterns associated with impaired pragmatic language comprehension in ASD, compared to typically developing children (TDC). MATERIALS AND METHODS: Functional magnetic resonance imaging (fMRI) was applied to 15 children with ASD and 18 TDC using the Korean pragmatic language task. RESULTS: Children with ASD were less accurate than TDC at comprehending idioms, particularly when they were required to interpret idioms with mismatched images (mismatched condition). Children with ASD also showed different patterns of neural activity than TDC in all three conditions (neutral, matched, and mismatched). Specifically, children with ASD showed decreased activation in the right inferior frontal gyrus (IFG) (Brodmann area 47) in the mismatched condition, compared with TDC (IFG; t(31)=3.17, p < 0.001). CONCLUSION: These results suggest that children with ASD face difficulties in comprehending pragmatic expressions and apply different pragmatic language processes at the neural level.
Autism Spectrum Disorder* ; Autistic Disorder* ; Child* ; Comprehension* ; Humans ; Magnetic Resonance Imaging ; Neurodevelopmental Disorders ; Prefrontal Cortex