The brain’s white matter, consisting of nerve fibers and their protective myelin coating essential for relaying signals between different brain regions, changes significantly with age, and can be studied using a noninvasive magnetic resonance imaging method called diffusion MRI.
Kurt Schilling, PhD, Bennett Landman, PhD, and colleagues examined white matter diffusion MRI data from 1,218 subjects ages 50-97 in three well-established cohorts including the Vanderbilt Memory & Aging Project. They quantified, for the first time, 11 macrostructure-based properties (volume, area and length) of nerve fiber bundles across 120 white matter pathways.
Fibers in the thalamic and striatal areas that are involved in the regulation of consciousness, alertness, procedural learning and memory showed the most age-related decline, compared to those in the limbic region, which is involved in behavioral and emotional responses.
These findings, published in Brain Structure and Function, indicate that macrostructural features can be useful for studying aging and could be a sensitive marker for neurodegenerative disorders such as Alzheimer’s disease.
Major funding for this project was provided by a National Science Foundation Career Award and National Institutes of Health grants EB017230 and AG073584.