Mapping brain abnormalities in boys with autism.

Area of Science:

• Neuroscience
• Developmental Psychology
• Radiology

Background:

• Autism spectrum disorder (ASD) presents with cognitive and behavioral variations, but consistent neuroanatomical patterns remain elusive.
• Neurodevelopmental models suggest abnormal early white matter growth in some autistic children, though findings vary.
• Previous research shows conflicting results regarding regional brain tissue excesses and deficits in autism.

Purpose of the Study:

• To investigate 3D brain volumetric differences in children with ASD using tensor-based morphometry.
• To map specific patterns of gray and white matter volume alterations in the brains of young autistic males.
• To explore potential links between observed brain volume patterns and impaired neuronal connectivity.

Main Methods:

• Utilized tensor-based morphometry on 3D T1-weighted brain MRIs from 24 male children with ASD and 26 healthy controls.
• Employed fluid registration to align all brain scans to a common anatomical template for precise comparison.
• Conducted statistical point-by-point analysis of deformation fields to identify significant volumetric differences.

Main Results:

• Autistic children exhibited significantly enlarged frontal lobes (left: 3.6%, right: 5.1%) and enlarged or trending larger volumes in all other lobes.
• Detected significant gray matter volume deficits in bilateral parietal, left temporal, and left occipital lobes (P = 0.038, corrected).
• Observed trend-level excesses in cerebral white matter volume alongside deficits in the cerebellar vermis and excesses in other cerebellar regions.

Conclusions:

• The observed pattern of regional brain volume excesses and deficits suggests impaired neuronal connectivity in children with ASD.
• Aberrant myelination or inflammatory processes may underlie these observed volumetric alterations.
• These findings contribute to understanding the heterogeneity of neuroanatomical findings in autism research.