The pubertal period involves dynamic white matter development. This period also corresponds with rapid gains in higher cognitive functions including attention, as well as increased risk of developing mental health difficulties. This longitudinal study comprised children aged 9–13 years (n = 130). Diffusion magnetic resonance imaging (dMRI) data were acquired (b = 2800s/mm², 60 directions) at two time-points. We derived measures of fibre density and morphology using the fixel-based analysis framework and performed a tract-based mixed-effects modelling analysis to understand patterns of white matter development with respect to age, sex, pubertal stage, and the change in pubertal stage. We observed significant increases in apparent fibre density across a large number of white matter pathways, including major association and commissural pathways. We observed a linear relationship between pubertal stage and fibre density and morphology in the right superior longitudinal fasciculus, and fibre morphology in the right inferior longitudinal fasciculus. Finally, we report a significant interaction between the change in pubertal stage and age in the development of fibre density, for left-lateralised association tracts. Overall, white matter development across ages 9–13 years involves the expansion of major white matter fibre pathways, with key association pathways linked with pubertal stage.

青春期涉及白质的动态发育。这一时期还伴随着包括注意力在内的高级认知功能的快速增强，以及出现心理健康问题的风险增加。这项纵向研究包括 9-13 岁的儿童 (n = 130)。在两个时间点采集扩散磁共振成像（dMRI）数据（b = 2800s/mm ² ，60个方向）。我们使用基于固定的分析框架得出纤维密度和形态的测量，并进行基于束的混合效应建模分析，以了解白质发育相对于年龄、性别、青春期阶段和青春期阶段变化的模式。我们观察到大量白质通路（包括主要关联通路和连合通路）的表观纤维密度显着增加。我们观察到青春期与右上纵束的纤维密度和形态以及右下纵束的纤维形态之间存在线性关系。最后，我们报告了青春期阶段和年龄的变化在左偏关联束的纤维密度发育中存在显着的相互作用。总体而言，9-13 岁年龄段的白质发育涉及主要白质纤维通路的扩展，其中关键关联通路与青春期阶段相关。