Investigating brain connectivity heritability in a twin study using diffusion imaging data

Area of Science:

• Neuroscience
• Genetics
• Medical Imaging

Background:

• Brain anatomical connectivity heritability is typically studied using diffusion-weighted imaging (DWI) with tensor modeling.
• Tensor modeling struggles to accurately represent complex crossing fibers within the brain.
• Previous studies suggest varying heritability across different brain networks.

Purpose of the Study:

• To investigate the heritability of brain connectivity using High Angular Resolution Diffusion Imaging (HARDI).
• To determine if different brain networks exhibit distinct heritability patterns.
• To identify specific brain tracts and regions with significant heritability.

Main Methods:

• Utilized High Angular Resolution Diffusion Imaging (HARDI) in a twin cohort (328 subjects: 70 MZ, 91 DZ pairs).
• Modeled water diffusion using Fiber Orientation Distribution (FOD) functions to capture multiple fiber orientations per voxel.
• Employed an ACE model incorporating test-retest precision to compute heritability of FOD peaks.

Main Results:

• Confirmed overall heritability for major white matter tracts.
• Demonstrated significant differences in heritability between various brain connectivity networks.
• Found inter-hemispheric connections to be more heritable than intra-hemispheric and cortico-spinal connections.
• Identified highly heritable tracts connecting medial frontal cortices, postcentral, paracentral gyri, and the right hippocampus.

Conclusions:

• Brain connectivity exhibits network-specific heritability, influenced by genetic factors.
• HARDI provides a more accurate method for assessing heritability of complex white matter tracts.
• Specific cortical connections, particularly inter-hemispheric ones, are strongly genetically influenced.