White matter asymmetry in the human brain: a diffusion tensor MRI study.

Area of Science:

• Neuroimaging
• Neuroscience
• Brain Anatomy

Background:

• Cerebral cortex asymmetry (grey matter) and connectivity (white matter) are linked to language and handedness.
• Voxel-based morphometry (VBM) using T1-weighted images has identified grey matter asymmetry but shows inconsistent results for white matter.
• Previous VBM studies have not detected handedness-related differences in grey or white matter.

Purpose of the Study:

• To investigate white matter asymmetries and handedness-related differences using Diffusion Tensor Imaging (DTI).
• To overcome the limitations of VBM in detecting white matter microstructural differences.

Main Methods:

• Utilized Diffusion Tensor Imaging (DTI) on two independent subject groups.
• Applied voxel-based statistical analyses to examine white matter composition and asymmetry.
• Focused on fractional anisotropy (FA) as a measure of white matter integrity.

Main Results:

• Observed a significant asymmetry in the arcuate fascicle, with higher fractional anisotropy (FA) in the left hemisphere.
• Identified handedness-related differences in white matter beneath the precentral gyrus contralateral to the dominant hand.
• Demonstrated robust findings even with small sample sizes, highlighting DTI's sensitivity.

Conclusions:

• DTI is a sensitive tool for detecting white matter microstructural differences and asymmetries.
• The study provides evidence for white matter correlates of language (arcuate fascicle) and handedness.
• DTI is effective for studying small patient populations due to its high sensitivity.