New reference models track lifespan changes in brain wiring

Researchers at the USC Mark and Mary Stevens Neuroimaging and Informatics Institute (Stevens INI) at the Keck School of Medicine of USC have created one of the largest reference models ever developed for the human brain, using diffusion MRI scans from more than 54,000 people to chart how the brain's communication pathways develop, mature, and decline across the lifespan.

Published in Nature Communications, the study provides the equivalent of "growth charts" for the brain's white matter - the vast network of neural wiring that allows brain regions to communicate. The new tool offers researchers a new way to detect subtle patterns linked to aging, Alzheimer's disease, schizophrenia risk, and other neurological and psychiatric conditions.

"Just as pediatric growth charts help clinicians determine whether a child's height or weight is developing as expected, these brain charts provide a reference for how the brain's neural pathways typically change over the lifespan," said Julio E. Villalón-Reina, MD, PhD, a postdoctoral researcher at the Stevens INI and the study's first author. "That gives us a powerful new way to identify when an individual's brain wiring falls outside the expected range."

White matter is essential for efficient communication throughout the brain. To study it, the team used diffusion MRI, an imaging method that tracks how water moves through brain tissue. Because water movement is shaped by microscopic features such as nerve fibers and myelin, the protective coating around them, diffusion MRI can reveal subtle changes in tissue organization not visible on standard brain scans. After compiling diffusion MRI data from 54,583 individuals across 19 international datasets, the researchers built statistical "growth and decline charts" for the brain's neural pathways, the network of nerve fibers that connects different regions of the brain and allows them to communicate.