Department of Psychology, Philipps-Universität Marburg, Marburg, 35039, Germany.
Center for Mind, Brain and Behavior - CMBB, Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Marburg, 35039, Germany.
Nat Commun. 2022 Feb 22;13(1):997. doi: 10.1038/s41467-022-28326-4.
Development of myelin, a fatty sheath that insulates nerve fibers, is critical for brain function. Myelination during infancy has been studied with histology, but postmortem data cannot evaluate the longitudinal trajectory of white matter development. Here, we obtained longitudinal diffusion MRI and quantitative MRI measures of longitudinal relaxation rate (R1) of white matter in 0, 3 and 6 months-old human infants, and developed an automated method to identify white matter bundles and quantify their properties in each infant's brain. We find that R1 increases from newborns to 6-months-olds in all bundles. R1 development is nonuniform: there is faster development in white matter that is less mature in newborns, and development rate increases along inferior-to-superior as well as anterior-to-posterior spatial gradients. As R1 is linearly related to myelin fraction in white matter bundles, these findings open new avenues to elucidate typical and atypical white matter myelination in early infancy.
髓鞘的发育对于大脑功能至关重要，它是一种包裹神经纤维的脂肪鞘。髓鞘在婴儿期的发育已经通过组织学进行了研究，但死后的数据无法评估白质发育的纵向轨迹。在这里，我们获得了 0、3 和 6 个月大的人类婴儿的纵向扩散 MRI 和纵向弛豫率（R1）的定量 MRI 测量值，并开发了一种自动方法来识别白质束并量化每个婴儿大脑中白质束的特性。我们发现，所有束中的 R1 均从新生儿增加到 6 个月大的婴儿。R1 的发育不均匀：在新生儿中不成熟的白质中发育速度更快，并且发育速度沿从下至上以及从前至后的空间梯度增加。由于 R1 与白质束中的髓鞘分数呈线性相关，这些发现为阐明早期婴儿典型和非典型白质髓鞘化开辟了新途径。
