PT  - JOURNAL ARTICLE
AU  - Håkon Grydeland
AU  - Petra E. Vértes
AU  - František Váša
AU  - Rafael Romero-Garcia
AU  - Kirstie Whitaker
AU  - Aaron F. Alexander-Bloch
AU  - Atle Bjørnerud
AU  - Ameera X. Patel
AU  - Donatas Sedervicius
AU  - Christian K. Tamnes
AU  - Lars T. Westlye
AU  - Simon R. White
AU  - Kristine B. Walhovd
AU  - Anders M. Fjell
AU  - Edward T. Bullmore
TI  - Waves of Maturation and Senescence in Micro-Structural MRI Markers of Human Cortical Myelination over the Lifespan
AID  - 10.1101/314195
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 314195
4099  - http://biorxiv.org/content/early/2018/10/23/314195.short
4100  - http://biorxiv.org/content/early/2018/10/23/314195.full
AB  - 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 7 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 30s but there was a second wave reaching stability in the 50s. Age at onset of decline was also bimodal: in some right hemisphere regions, the curve declined from the 60s, 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.