PT  - JOURNAL ARTICLE
AU  - Mareike Grotheer
AU  - Mona Rosenke
AU  - Hua Wu
AU  - Holly Kular
AU  - Francesca R. Querdasi
AU  - Vaidehi Natu
AU  - Jason D. Yeatman
AU  - Kalanit Grill-Spector
TI  - Catch me if you can: Least myelinated white matter develops fastest during early infancy
AID  - 10.1101/2021.03.29.437583
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.03.29.437583
4099  - http://biorxiv.org/content/early/2021/03/30/2021.03.29.437583.short
4100  - http://biorxiv.org/content/early/2021/03/30/2021.03.29.437583.full
AB  - Development of myelin, a fatty sheath that insulates nerve fibers, is critical for brain function. Myelination during infancy has been studied in postmortem histology, but such data cannot evaluate the developmental trajectory of the white matter bundles of the brain. To address this gap in knowledge, we (i) obtained longitudinal diffusion MRI measures and quantitative MRI measures of T1, which is sensitive to myelin, from newborns to 6-months-old infants, and (ii) developed an automated fiber quantification method that identifies bundles from dMRI and quantifies their T1 development in infants. Here we show that both along the length of each bundle and across bundles, T1 decreases from newborns to 6 months-old’s and the rate of T1 decrease is inversely correlated with T1 at birth. As lower T1 indicates more myelin, these data suggest that in early infancy white matter bundles myelinate at different rates such that less mature bundles at birth develop faster to catch-up with the other bundles. We hypothesize that this development reflects experience-dependent myelination, which may promote efficient and coordinated neural communication. These findings open new avenues to measure typical and atypical white matter development in early infancy, which has important implications for early identification of neurodevelopmental disorders.Competing Interest StatementThe authors have declared no competing interest.