Department of Psychology, Center for the Study of Human Cognition, University of Oslo, Oslo, Norway.
Hum Brain Mapp. 2010 Oct;31(10):1609-25. doi: 10.1002/hbm.20962.
Higher-order cognitive functions are supported by distributed networks of multiple interconnected cortical and subcortical regions. Efficient cognitive processing depends on fast communication between these regions, so the integrity of the connections between them is of great importance. It is known that white matter (WM) development is a slow process, continuing into adulthood. While the significance of cortical maturation for intellectual development is described, less is known about the relationships between cognitive functions and maturation of WM connectivity. In this cross-sectional study, we investigated the associations between intellectual abilities and development of diffusion tensor imaging (DTI) derived measures of WM microstructure in 168 right-handed participants aged 8-30 years. Independently of age and sex, both verbal and performance abilities were positively related to fractional anisotropy (FA) and negatively related to mean diffusivity (MD) and radial diffusivity (RD), predominantly in the left hemisphere. Further, verbal, but not performance abilities, were associated with developmental differences in DTI indices in widespread regions in both hemispheres. Regional analyses showed relations with both FA and RD bilaterally in the anterior thalamic radiation and the cortico-spinal tract and in the right superior longitudinal fasciculus. In these regions, our results suggest that participants with high verbal abilities may show accelerated WM development in late childhood and a subsequent earlier developmental plateau, in contrast to a steadier and prolonged development in participants with average verbal abilities. Longitudinal data are needed to validate these interpretations. The results provide insight into the neurobiological underpinnings of intellectual development.
高级认知功能由多个相互连接的皮质和皮质下区域的分布式网络支持。有效的认知处理依赖于这些区域之间的快速通信，因此它们之间连接的完整性非常重要。已知白质（WM）的发育是一个缓慢的过程，一直持续到成年期。虽然描述了皮质成熟对智力发展的重要性，但对于认知功能与 WM 连接成熟之间的关系知之甚少。在这项横断面研究中，我们调查了 168 名右利手参与者的智力能力与基于扩散张量成像（DTI）的 WM 微观结构测量值之间的关系，这些参与者的年龄在 8 至 30 岁之间。独立于年龄和性别，言语和表现能力均与各向异性分数（FA）呈正相关，与平均扩散系数（MD）和辐射扩散系数（RD）呈负相关，主要在左半球。此外，言语能力而不是表现能力与两个半球广泛区域的 DTI 指数的发育差异相关。区域分析显示，在前丘脑辐射和皮质脊髓束以及右侧上纵束中双侧与 FA 和 RD 均存在关系。在这些区域，我们的结果表明，言语能力较高的参与者可能在儿童后期表现出 WM 发育加速，随后出现发育高原，而言语能力一般的参与者的发育则更为稳定和持久。需要纵向数据来验证这些解释。研究结果为智力发展的神经生物学基础提供了深入的了解。
