Constrained spherical deconvolution-based tractography and tract-based spatial statistics show abnormal...

Area of Science:

• Neuroimaging
• Autism Spectrum Disorder Research
• White Matter Microstructure

Background:

• Asperger syndrome (AS), a form of autism spectrum disorder (ASD), is characterized by social interaction impairments and restricted behaviors.
• Understanding the neural underpinnings of AS is crucial for developing targeted interventions.

Purpose of the Study:

• To investigate differences in white matter (WM) neural structure between adults with AS and neurotypical controls.
• To explore correlations between WM microstructural changes and symptom severity in AS.

Main Methods:

• Diffusion-weighted magnetic resonance imaging (dMRI) was used to acquire data from 14 adult males with AS and 19 matched controls.
• Tract-based spatial statistics (TBSS) and constrained spherical deconvolution (CSD)-based tractography analyzed voxelwise and tract-level differences in fractional anisotropy (FA).
• Correlations between FA and Autism Spectrum Quotient (AQ), Empathy Quotient, and Systemizing Quotient were examined.

Main Results:

• TBSS revealed widespread bilateral increases in FA in individuals with AS, notably in the superior longitudinal fasciculus and inferior longitudinal fasciculus (ILF).
• CSD-based tractography confirmed FA increases, with the left ILF showing statistical significance after Bonferroni correction.
• A correlation was found between higher AQ scores and increased FA in the right inferior fronto-occipital fasciculus (IFO) across the entire group.

Conclusions:

• Adults with AS exhibit local and tract-level abnormalities in white matter microstructure.
• The left ILF is a key area showing significant microstructural differences in this AS cohort.
• These findings contribute to understanding the neurobiology of Asperger syndrome.