Age-Related Cortical Thinning is Associated with Layer-Specific Changes in T1w/T2w Profiles

Motivation: Myelination across cortical layers may change differently with cortical thinning as a result of aging. Identifying layer-specific changes could provide insights into mechanisms underlying age-related structural changes in the brain. Goal(s): We examined cortical T1w/T2w profiles to detect changes associated with cortical thinning. Approach: We conducted regressions to identify layer-specific relationships with age and cortical thickness, utilizing T1w/T2w cortical profiles across multiple ROIs from 412 older adults. Results: Cortical thickness negatively correlated with T1w/T2w ratios in middle-upper layers, suggesting cortical thinning is associated with increased myelination. Impact: Regions with significant age-related cortical thinning show pronounced T1w/T2w changes, suggesting myelination's role in cortical thinning. This enhances understanding of aging-related brain changes, with myelin preservation as a potential target for interventions to mitigate age-related cognitive decline.