INSERM, U992, Neurospin, 91191 Gif/Yvette, France.
J Neurosci. 2011 Jan 26;31(4):1500-6. doi: 10.1523/JNEUROSCI.4141-10.2011.
Human infants, unlike even closely related primates, exhibit a remarkable capacity for language learning. Yet how the underlying anatomical network matures remains largely unknown. The classical view is that of a largely immature brain comprising only a few islands of maturity in primary cortices. This view has favored a description of learning based on bottom-up algorithms and has tended to discard the role of frontal regions, which were assumed to be barely functional early on. Here, using an index based on the normalized T2-weighted magnetic resonance signal, we have quantified maturation within the linguistic network in fourteen 1- to 4-month-old infants. Our results show first that the ventral superior temporal sulcus (STS), and not the inferior frontal area, is the less mature perisylvian region. A significant difference of maturation in the STS favoring the right side is an early testimony of the distinctive left-right development of this structure observed during the whole life. Second, asymmetries of maturation in Broca's area were correlated with asymmetries in the posterior STS and in the parietal segment of the arcuate fasciculus, suggesting that an efficient frontotemporal dorsal pathway might provide infants with a phonological loop circuitry much earlier than expected.
人类婴儿，与亲缘关系密切的灵长类动物不同，表现出非凡的语言学习能力。然而，基础解剖网络的成熟方式在很大程度上仍然未知。传统观点认为，大脑尚未完全成熟，仅在初级皮质中有几个成熟的岛屿。这种观点支持基于自下而上算法的学习描述，并倾向于排除额叶区域的作用，因为早期假设这些区域几乎没有功能。在这里，我们使用基于归一化 T2 加权磁共振信号的指数，在 1 至 4 个月大的 14 名婴儿中量化了语言网络中的成熟度。我们的结果首先表明，腹侧上颞回（STS），而不是下额叶区域，是语言网络中较不成熟的岛叶区域。成熟度的显著右偏侧化是该结构在整个生命过程中观察到的左右发展独特性的早期证据。其次，布罗卡区的成熟度不对称与后部 STS 和弓状束的顶叶节段的成熟度不对称相关，这表明有效的额颞叶背侧通路可能会更早地为婴儿提供语音环路电路。
