Characterizing Subcortical Structural Heterogeneity in Autism.

Area of Science:

• Neuroimaging
• Developmental neuroscience
• Autism spectrum disorder research

Background:

• Autism spectrum disorder (ASD) exhibits significant heterogeneity in brain structure and function.
• Previous neuroimaging studies on subcortical structures like the thalamus, globus pallidus, and striatum in ASD have yielded inconsistent findings.
• These subcortical regions are crucial for sensory processing and motor control, functions often atypical in ASD.

Approach:

• Utilized a large, cross-sectional dataset (n=3145, 1045-1318 after QC) of T1-weighted MRI scans from 32 sites.
• Examined both volumetric and localized shape differences in the thalamus, globus pallidus, and striatum in individuals with ASD.
• Investigated potential heterogeneity sources: sex, age, and intelligence quotient (IQ), employing a meta-analytic technique with strict quality control.

Key Points:

• No significant volumetric differences were found in the thalamus, globus pallidus, or striatum in ASD.
• Identified localized, fine-grained shape differences across all three investigated subcortical structures in ASD.
• Age, but not sex or IQ, significantly improved statistical models for pallidum and striatum shape analysis, indicating age-dependent effects.

Conclusions:

• Neurodevelopment of the striatum, globus pallidus, and thalamus is atypically altered in ASD.
• These alterations manifest as subtle, location-dependent shape variations rather than overall volume changes.
• The observed neuroanatomical differences are non-uniform across the lifespan, highlighting age as a critical factor in ASD neurobiology.