Objectives: To present initial structural neuroimaging findings from a new cohort of young children with autism using surface-based methods for cortical morphometry that (i) directly measure the two biologically distinct sub-components of cortical volume - cortical thickness and surface area and (ii) map cortical thickness at high spatially resolution throughout the cortical sheet.
Methods: This was a cross-sectional case control neuroimaging study conducted in a Federal clinical research institute. We included 75 male children with autism and 33 typically developing male controls aged 2 through 6 years. Primary outcome measures of interest were (i) Global and lobar cortical volume, thickness and surface area, and (ii) cortical thickness at ~80,000 points.
Results: Children with autism showed age-related global cortical volume excesses relative to TDCs, which were driven by attenuation of age-related cortical thickness reduction relative to TDCs. These thickness-driven volume excesses were apparent in all lobes, but uniquely compounded in frontal lobes by an exaggerated age-related surface area increase in children with autism relative to TDCs. Fine-mapping group differences in cortical thickness identified disruptions of cortical anatomy in autism that were already localized at an early age to regions involved in the processing of language, biological movement and social information, as well as to executive prefrontal systems involved in behavioral regulation.
Conclusions: Our findings (i) parse cortical volume abnormalities in autism into more biologically tractable sub-components, and (ii) show that disease mechanisms in autism can already produce targeted disruption of cortical anatomy by early childhood.
See more of: Brain Imaging: fMRI-Social Cognition and Emotion Perception
See more of: Brain Structure & Function