Department of Psychology and Stanford Center for Cognitive and Neurobiological Imaging, Stanford University, Stanford, CA 94035, USA.
Proc Natl Acad Sci U S A. 2012 Oct 30;109(44):E3045-53. doi: 10.1073/pnas.1206792109. Epub 2012 Oct 8.
White matter tissue properties are highly correlated with reading proficiency; we would like to have a model that relates the dynamics of an individual's white matter development to their acquisition of skilled reading. The development of cerebral white matter involves multiple biological processes, and the balance between these processes differs between individuals. Cross-sectional measures of white matter mask the interplay between these processes and their connection to an individual's cognitive development. Hence, we performed a longitudinal study to measure white-matter development (diffusion-weighted imaging) and reading development (behavioral testing) in individual children (age 7-15 y). The pattern of white-matter development differed significantly among children. In the left arcuate and left inferior longitudinal fasciculus, children with above-average reading skills initially had low fractional anisotropy (FA) that increased over the 3-y period, whereas children with below-average reading skills had higher initial FA that declined over time. We describe a dual-process model of white matter development comprising biological processes with opposing effects on FA, such as axonal myelination and pruning, to explain the pattern of results.
大脑白质组织的性质与阅读能力高度相关；我们希望建立一个模型，将个体白质发展的动态与其熟练阅读能力的获得联系起来。大脑白质的发育涉及多个生物学过程，个体之间这些过程的平衡也有所不同。白质的横断面测量掩盖了这些过程之间的相互作用及其与个体认知发展的联系。因此，我们进行了一项纵向研究，以测量个体儿童（7-15 岁）的白质发育（弥散加权成像）和阅读能力发展（行为测试）。白质发育的模式在儿童中存在显著差异。在左侧弓状束和左侧下纵束中，阅读能力高于平均水平的儿童最初的各向异性分数（FA）较低，在 3 年期间逐渐增加，而阅读能力低于平均水平的儿童最初的 FA 较高，且随时间逐渐下降。我们描述了一个白质发育的双过程模型，该模型包含了对 FA 具有相反影响的生物过程，如轴突髓鞘形成和修剪，以解释结果的模式。
