Microstructural Characterization of Short Association Fibers Related to Long-Range White Matter Tracts in Normative...

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Neuroimaging

Background:

• Short association fibers (SAFs) are crucial for local cortical connections but are understudied due to tractography limitations.
• Understanding SAF development is key to advancing knowledge of neurodevelopment from childhood to young adulthood.

Purpose of the Study:

• To map SAFs relative to long-range white matter tracts.
• To characterize typical neurodevelopmental changes in these pathways.
• To investigate microstructural relationships between SAFs and long-range tracts.

Main Methods:

• Quantitative diffusion tractography and advanced diffusion modeling (DTI, NODDI) were used.
• A cohort of 616 participants aged 5.6-21.9 years was analyzed.
• Robust linear regression models assessed microstructural features (FA, MD, AD, RD, ICVF, ISOVF, ODI).

Main Results:

• Both SAFs and long-range tracts showed similar age-related patterns in microstructural changes.
• FA, AD, and ODI differed significantly between SAFs and long-range tracts, indicating distinct developmental trajectories.
• Sex-based differences were observed in MD, RD, and ICVF, highlighting neurodevelopmental variations.

Conclusions:

• This normative study reveals typical microstructural development in SAFs and long-range white matter.
• Findings suggest distinct developmental trajectories for superficial and deep white matter.
• Provides a foundation for studying atypical development and neurological disorders.