Nature Communications, Published online: 29 August 2026; doi:10.1038/s41467-026-77073-3 This study presents the development and aging principles of myelination in 214 brain regions using large-scale dataset spanning birth through 100 years. The results provide strong evidence for region-specific variability in multiscale brain development, with some areas exhibiting earlier maturation in myelination and others in macrostructural properties.