ANS: aberrant neurodevelopment of the social cognition network in adolescents with autism spectrum disorders

Abstract

Background: Autism spectrum disorders (ASD) are characterized by aberrant neurodevelopment. Although the ASD brain undergoes precocious growth followed by decelerated maturation during early postnatal period of childhood, the neuroimaging approach has not been empirically applied to investigate how the ASD brain develops during adolescence.

Methodology/principal findings: We enrolled 25 male adolescents with high functioning ASD and 25 typically developing controls for voxel-based morphometric analysis of structural magnetic resonance image. Results indicate that there is an imbalance of regional gray matter volumes and concentrations along with no global brain enlargement in adolescents with high functioning ASD relative to controls. Notably, the right inferior parietal lobule, a role in social cognition, have a significant interaction of age by groups as indicated by absence of an age-related gain of regional gray matter volume and concentration for neurodevelopmental maturation during adolescence.

Conclusions/significance: The findings indicate the neural correlates of social cognition exhibits aberrant neurodevelopment during adolescence in ASD, which may cast some light on the brain growth dysregulation hypothesis. The period of abnormal brain growth during adolescence may be characteristic of ASD. Age effects must be taken into account while measures of structural neuroimaging have been clinically put forward as potential phenotypes for ASD.

Figure 1. Direct comparison between groups controlling for age, IQ, and total gray matter volume.

The gray matter regions showing significant group differences between individuals with ASD and TDC are rendered onto the averaged coronal images of the whole sample (N = 50) (Voxel threshold: uncorrected P<0.001). The y-coordinate for each coronal slice in the Montreal Neurological Institute space is given in millimeters. L: left, R: right. Abbreviations: LG, lingual gyrus; SPL, superior parietal lobule; FG, fusiform gyrus; IFG, inferior frontal gyrus; MFG, medial frontal gyrus.

Figure 2. Significant interaction of age by group in the relative gray matter content.

a. Inferior parietal Lobule. There is an age-related loss in the adolescents with ASD whilst an age-related gain in the TDC. b. Posterior cingulate. There is no age-related change in ASD but an age-related gain in the TDC.