Researchers at the University of North Carolina at Chapel Hill mapped brain-wide myelination across the entire human lifespan, publishing their findings in Nature Communications. The study analyzed magnetic resonance imaging T1w/T2w ratios across 214 brain regions in individuals aged 0 to 100 years.
Sahar Ahmad, Khoi Minh Huynh, Guoye Lin, and Pew-Thian Yap found that changes in the T1w/T2w ratio across all 214 brain regions follow a triphasic pattern. The first stage consists of rapid growth during infancy, termed the primary myelination phase. The second stage brings a reacceleration during adolescence and adulthood, marked as the secondary myelination phase. The final stage is a late-life decline driven by demyelination.
Past studies remained fragmented because they focused either on selected brain structures or on narrow age ranges. By tracking 214 separate regions, the authors mapped local timing differences and regional variation in both myelination and demyelination across a century of human life. The researchers also measured regional brain volume and cortical thickness to evaluate how macroscale structural changes correlate with microscale myelination shifts.
The investigation drew data from several major neuroimaging initiatives. These included the Baby Connectome Project, the developing Human Connectome Project, the Human Connectome Project, HCP Lifespan, and the Adolescent Brain Cognitive Development Study. Computing work ran on infrastructure at the Biomedical Research Imaging Center at UNC Chapel Hill under grants from the National Institutes of Health.
