Waves of Maturation and Senescence in Micro-structural MRI Markers of Human Cortical Myelination over the Lifespan

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 29; no. 3; pp. 1369 - 1381
• Main Authors: Grydeland, Håkon, Vértes, Petra E, Váša, František, Romero-Garcia, Rafael, Whitaker, Kirstie, Alexander-Bloch, Aaron F, Bjørnerud, Atle, Patel, Ameera X, Sederevičius, Donatas, Tamnes, Christian K, Westlye, Lars T, White, Simon R, Walhovd, Kristine B, Fjell, Anders M, Bullmore, Edward T
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.03.2019
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Cerebral Cortex - growth & development; Child; Connectome; Female; Humans; Longevity; Magnetic Resonance Imaging; Male; Middle Aged; Myelin Sheath - physiology; Original; Young Adult; micro-structure; myelin; magnetic resonance imaging; cortical development; lifespan
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhy330

Abstract Seminal human brain histology work has demonstrated developmental waves of myelination. Here, using a micro-structural magnetic resonance imaging (MRI) marker linked to myelin, we studied fine-grained age differences to deduce waves of growth, stability, and decline of cortical myelination over the life-cycle. In 484 participants, aged 8–85 years, we fitted smooth growth curves to T1- to T2-weighted ratio in each of 360 regions from one of seven cytoarchitectonic classes. From the first derivatives of these generally inverted-U trajectories, we defined three milestones: the age at peak growth; the age at onset of a stable plateau; and the age at the onset of decline. Age at peak growth had a bimodal distribution comprising an early (pre-pubertal) wave of primary sensory and motor cortices and a later (post-pubertal) wave of association, insular and limbic cortices. Most regions reached stability in the 30-s but there was a second wave reaching stability in the 50-s. Age at onset of decline was also bimodal: in some right hemisphere regions, the curve declined from the 60-s, but in other left hemisphere regions, there was no significant decline from the stable plateau. These results are consistent with regionally heterogeneous waves of intracortical myelinogenesis and age-related demyelination.