Hemispheric Differences in White Matter Microstructure between Two Profiles of Children with High Intelligence...

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• High intelligence quotient (HIQ) is associated with distinct cognitive profiles.
• Understanding the neural underpinnings of different HIQ profiles is crucial for cognitive development research.
• Previous research has explored brain structure in HIQ, but direct comparisons of homogeneous and heterogeneous profiles are limited.

Purpose of the Study:

• To investigate and compare the white matter (WM) microstructure neural substrate of two distinct high intelligence quotient (HIQ) profiles in children.
• To differentiate the neuroanatomical characteristics of homogeneous (Hom-HIQ) versus heterogeneous (Het-HIQ) IQ profiles.

Main Methods:

• Utilized diffusion tensor imaging (DTI) to assess WM microstructure in children with Hom-HIQ (n=20) and Het-HIQ (n=24) groups, alongside a control group.
• Employed tract-based spatial statistics (TBSS) to analyze regional differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).
• Quantitatively measured microstructural parameters across 48 WM regions and 21 major fiber bundles.

Main Results:

• Hom-HIQ children exhibited higher FA in widespread WM regions, including central and associative intra-hemispheric pathways, compared to Het-HIQ children.
• Both HIQ groups showed increased AD in numerous WM regions relative to controls, with distinct hemispheric lateralization patterns.
• Het-HIQ group displayed leftward lateralization (ratio 1.38), while Hom-HIQ group showed rightward lateralization (ratio 0.78) in AD differences.

Conclusions:

• Enhanced inter- and intra-hemispheric WM integrity is characteristic of children with HIQ.
• Distinct neural substrates differentiate Hom-HIQ and Het-HIQ profiles, particularly in WM microstructure and hemispheric organization.
• The observed lateralization patterns correlate with cognitive profiles: leftward for Het-HIQ (verbal) and rightward for Hom-HIQ (global processing).