Lifespan trajectories of the morphology and tractography of the corpus callosum: A 5.0 T MRI study.

Abstract

The corpus callosum (CC) is the largest white matter fiber bundle connecting the two hemispheres, facilitating interhemispheric integration and hemispheric specialization. Neuroimaging studies have identified the CC as a marker for aging and various neuropsychiatric disorders. However, high-resolution imaging and detailed lifespan characterizations of CC morphology and connectivity remain limited. Utilizing the high-resolution brain imaging capabilities of 5.0 T ultra-high-field MRI, we collected lifespan data from 266 healthy adults aged 18-89. We segmented and measured the midsagittal area, circularity, thickness, and tractography of the CC using linear and nonlinear models. Our analysis revealed that, despite regional variations, these measures generally exhibited a brief initial increase followed by a rapid decline. Coupling analysis further indicated that the correlation between CC morphology and tractography strengthens with age. External validation and correlation with cognitive-behavioral tests showed that CC subregions with significant age-related changes predominantly involve areas connecting the frontal and parietal networks. These findings provide new insights into the lifespan evolution of CC morphology and tractography, as well as their degeneration associated with specific functions.