Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neuropsychology, 04103 Leipzig, Germany.
Cereb Cortex. 2011 Feb;21(2):459-66. doi: 10.1093/cercor/bhq108. Epub 2010 Jun 21.
The 2 major language-relevant cortical regions in the human brain, Broca's area and Wernicke's area, are connected via the fibers of the arcuate fasciculus/superior longitudinal fasciculus (AF/SLF). Here, we compared this pathway in adults and children and its relation to language processing during development. Comparison of fiber properties demonstrated lower anisotropy in children's AF/SLF, arguing for an immature status of this particular pathway with conceivably a lower degree of myelination. Combined diffusion tensor imaging (DTI) data and functional magnetic resonance imaging (fMRI) data indicated that in adults the termination of the AF/SLF fiber projection is compatible with functional activation in Broca's area, that is pars opercularis. In children, activation in Broca's area extended from the pars opercularis into the pars triangularis revealing an alternative connection to the temporal lobe (Wernicke's area) via the ventrally projecting extreme capsule fiber system. fMRI and DTI data converge to indicate that adults make use of a more confined language network than children based on ongoing maturation of the structural network. Our data suggest relations between language development and brain maturation and, moreover, indicate the brain's plasticity to adjust its function to available structural prerequisites.
人类大脑中与语言相关的两个主要皮质区域，布罗卡区和韦尼克区，通过弓状束/上纵束（AF/SLF）的纤维连接。在这里，我们比较了成人和儿童的这条通路及其与发育过程中语言处理的关系。纤维特性的比较表明，儿童的 AF/SLF 各向异性较低，这表明该特定通路的不成熟状态，可能有较低程度的髓鞘形成。弥散张量成像（DTI）数据和功能磁共振成像（fMRI）数据的结合表明，在成人中，AF/SLF 纤维投射的终点与布罗卡区（即三角部）的功能激活相匹配。而在儿童中，布罗卡区的激活从三角部扩展到了三角部，通过腹侧投射的极胶囊纤维系统显示出与颞叶（韦尼克区）的替代连接。fMRI 和 DTI 数据的融合表明，基于结构网络的持续成熟，成人比儿童使用更局限的语言网络。我们的数据表明了语言发展与大脑成熟之间的关系，并且表明大脑具有调整其功能以适应可用结构前提的可塑性。
