Functional Alterations Associated with Structural Abnormalities in Adults with High-Functioning Autism Spectrum...

Area of Science:

• Neuroimaging science
• Autism Spectrum Disorder (ASD) research
• Brain structure and function

Background:

• Combining structural and functional neuroimaging provides methodological advantages for understanding autism spectrum disorder (ASD).
• A knowledge gap exists regarding studies that integrate both structural and functional analyses in ASD.
• Investigating these integrated approaches is crucial for a comprehensive understanding of ASD neurobiology.

Purpose of the Study:

• To investigate structural abnormalities and their associated functional differences in a developmentally homogeneous cohort of individuals with ASD.
• To identify specific brain regions with structural differences using voxel-based morphometry (VBM).
• To explore the functional connectivity patterns associated with these structural differences using resting-state functional connectivity (RsFc).

Main Methods:

• Whole-brain voxel-based morphometry (VBM) was used to analyze gray matter (GM) volume differences between 28 ASD participants and 38 healthy controls (HC).
• VBM-identified clusters served as regions of interest (ROIs) for subsequent resting-state functional connectivity (RsFc) analysis.
• RsFc analysis examined brain connectivity patterns in high-functioning ASD (HF-ASD) participants.

Main Results:

• VBM revealed right-lateralized GM abnormalities in ASD, including reduced volume in cerebellar lobules VIIb/VIIIa and increased volume in posterior middle/superior temporal gyri (BA 21/22).
• RsFc analysis in HF-ASD showed hypoconnectivity between the cerebellar VBM cluster and right cerebral cortical regions (superior parietal lobule, occipital pole).
• The temporal lobe VBM cluster showed hypoconnectivity with prefrontal cortex and insula, and altered connectivity with default mode network regions.

Conclusions:

• Cerebro-cerebellar intrinsic functional dysconnectivity in ASD, identified through VBM-derived ROIs, may elucidate compensatory mechanisms.
• Findings suggest the cerebellum as a potential target for ASD diagnostic, predictive, prognostic, and therapeutic interventions.
• The study supports the existence of functional abnormalities in ASD and highlights a likely relationship between structural and functional brain differences.