Differences in age-dependent neural correlates of semantic processing between youths with autism spectrum disorder and typically developing youths.

Individuals with autism spectrum disorders (ASD) have aberrant neural activity during semantic judgments. We aimed to examine age-dependent neural correlates of semantic processing in boys with ASD as compared to typically developing boys (TD). We used functional MRI to investigate 37 boys with ASD (mean age = 13.3 years, standard deviation = 2.4) and 35 age-, sex-, Intelligence quotient (IQ)- and handedness-matched TD boys (mean age = 13.3 years, standard deviation = 2.7) from age 8 to 18 years. Participants had to indicate whether pairs of Chinese characters presented visually were related in meaning. Group (ASD, TD) × Age (Old, Young) ANOVA was used to examine the difference of age-related changes. Direct comparisons between the adolescent group and the child group were also performed. The behavioral results showed that the ASD group had lower accuracy in the related condition relative to the TD group. The neuroimaging results showed greater activation in the cuneus and less activation in the left inferior frontal gyrus in boys with ASD than TD boys. Children with ASD produced greater activation in the cuneus than TD children. Adolescents with ASD showed reduced left IFG activation as compared to TD adolescents. Our findings suggest that TD boys may engage more in higher-level processing of retrieving or selecting semantic features while boys with ASD may rely more on lower-level visual processing during semantic judgments. The findings imply different functional organizations of the semantic system between the two groups. Autism Res 2016, 9: 1263-1273.