Genc Sila, Seal Marc L, Dhollander Thijs, Malpas Charles B, Hazell Philip, Silk Timothy J
Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia.
Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia.
Neuroimage. 2017 Aug 1;156:286-292. doi: 10.1016/j.neuroimage.2017.05.017. Epub 2017 May 19.
Recent neurodevelopmental research supports the contribution of pubertal stage to local and global grey and white matter remodelling. Little is known, however, about white matter microstructural alterations at pubertal onset. This study investigated differences in white matter properties between pre-pubertal and pubertal children using whole brain fixel-based analysis (FBA) of the microscopic density and macroscopic cross-section of fibre bundles. Diffusion-weighted imaging data were acquired for 74 typically developing children (M=10.4, SD=.43 years, 31 female) at 3.0T (60 diffusion gradient directions, b-value=2800s/mm). Group comparisons of fibre density (FD) and fibre cross-section (FC) were made between age-matched pre-pubertal and pubertal groups, and post-hoc analyses were performed on regions of interest (ROIs) defined in the splenium, body and genu of the corpus callosum. Significant fixel-wise differences in FD were observed between the pubertal groups, where the pubertal group had significantly higher FD compared with age-matched pre-pubertal children, localised to the posterior corpus callosum. Post-hoc analyses on mean FD in the corpus callosum ROIs revealed group differences between the pubertal groups in the splenium, but not body or genu. The observed higher apparent fibre density in the splenium suggests that pubertal onset coincides with white matter differences explained by increasing axon diameter. This may be an important effect to account for over pubertal development, particularly for group studies where age-matched clinical and typical populations may be at various stages of puberty.
近期的神经发育研究支持青春期阶段对局部和整体灰质与白质重塑的作用。然而，对于青春期开始时白质微观结构的改变却知之甚少。本研究使用基于体素的全脑分析（FBA）来研究青春期前和青春期儿童之间白质特性的差异，该分析涉及纤维束的微观密度和宏观横截面积。对74名发育正常的儿童（平均年龄M = 10.4岁，标准差SD = 0.43岁，31名女性）在3.0T磁场下采集扩散加权成像数据（60个扩散梯度方向，b值 = 2800s/mm²）。在年龄匹配的青春期前和青春期组之间进行纤维密度（FD）和纤维横截面积（FC）的组间比较，并对胼胝体压部、体部和膝部定义的感兴趣区域（ROI）进行事后分析。在青春期组之间观察到FD存在显著的体素水平差异，青春期组的FD显著高于年龄匹配的青春期前儿童，主要集中在胼胝体后部。对胼胝体ROI中平均FD的事后分析显示，青春期组在压部存在组间差异，但在体部或膝部没有。在压部观察到的较高表观纤维密度表明，青春期开始与轴突直径增加所解释的白质差异相吻合。这可能是青春期发育过程中的一个重要影响因素，特别是对于年龄匹配的临床和典型人群可能处于青春期不同阶段的分组研究。
