Network-specific corpus callosum aging and age-moderated cognitive associations using tract-to-region analysis

Area of Science:

• Neuroscience
• Aging Research
• Neuroimaging

Background:

• The corpus callosum (CC), the brain's largest white matter structure, shows age-related atrophy.
• Understanding how CC network-specific connections age and impact cognition is limited.

Purpose of the Study:

• To investigate network-specific aging trajectories of the corpus callosum.
• To examine the relationship between CC integrity, cognitive performance, and aging.

Main Methods:

• Diffusion-weighted imaging data from 718 healthy adults (36-100 years) from the Human Connectome Project-Aging dataset were analyzed.
• A tract-to-region approach quantified CC tract density within seven functional networks.
• Cubic polynomial models and correlation/moderation analyses assessed aging patterns and brain-behavior relationships.

Main Results:

• Distinct aging patterns were observed across CC networks; Somatomotor and Default Mode networks showed the steepest declines.
• Visual and Limbic networks demonstrated relative preservation of CC tract density.
• CC tract density was associated with executive function, memory, and motor performance, with these associations strengthening significantly with age.

Conclusions:

• The corpus callosum exhibits network-specific aging, with accelerated decline in high-order association networks and preservation in sensory networks.
• Callosal integrity becomes increasingly vital for cognitive function maintenance in older age.
• Age-dependent moderation highlights the growing importance of CC connectivity for cognition in later life.