Hitachi, Ltd., Advanced Research Laboratory, Saitama, Japan; JST (Japan Science and Technology Agency)/CREST (Core Research for Evolutional Science and Technology), Saitama, Japan.
Hum Brain Mapp. 2012 Sep;33(9):2092-103. doi: 10.1002/hbm.21350. Epub 2011 Jun 28.
Considerable knowledge on neural development related to speech perception has been obtained by functional imaging studies using near-infrared spectroscopy (optical topography). In particular, a pioneering study showed stronger left-dominant activation in the temporal lobe for (normal) forward speech (FW) than for (reversed) backward speech (BW) in neonates. However, it is unclear whether this stronger left-dominant activation for FW is equally observed for any language or is clearer for the mother tongue. We hypothesized that the maternal language elicits clearer activation than a foreign language in newborns because of their prenatal and/or few-day postnatal exposure to the maternal language. To test this hypothesis, we developed a whole-head optode cap for 72-channel optical topography and visualized the spatiotemporal hemodynamics in the brains of 17 Japanese newborns when they were exposed to FW and BW in their maternal language (Japanese) and in a foreign language (English). Statistical analysis showed that all sound stimuli together induced significant activation in the bilateral temporal regions and the frontal region. They also showed that the left temporal-parietal region was significantly more active for Japanese FW than Japanese BW or English FW, while no significant difference between FW and BW was shown for English. This supports our hypothesis and suggests that the few-day-old brain begins to become attuned to the maternal language. Together with a finding of equivalent activation for all sound stimuli in the adjacent measurement positions in the temporal region, these findings further clarify the functional organization of the neonatal brain.
通过使用近红外光谱（光学拓扑）的功能成像研究，已经获得了大量与语音感知相关的神经发育知识。特别是，一项开创性的研究表明，在新生儿中，正常的前向语音（FW）比反向语音（BW）在颞叶中引起更强的左优势激活。然而，FW 的这种更强的左优势激活是否同样适用于任何语言，或者母语是否更清晰，尚不清楚。我们假设，由于新生儿在产前和/或出生后几天内接触母语，因此母语会引起比外语更清晰的激活。为了验证这一假设，我们开发了一种用于 72 通道光学拓扑的全头光导帽，并在 17 名日本新生儿暴露于母语（日语）和外语（英语）的 FW 和 BW 时，可视化了他们大脑中的时空血液动力学。统计分析表明，所有声音刺激一起在双侧颞区和额区引起显著激活。它们还表明，日语 FW 比日语 BW 或英语 FW 在左颞顶区更活跃，而英语 FW 和 BW 之间没有显著差异。这支持了我们的假设，并表明几天大的大脑开始适应母语。结合颞区相邻测量位置对所有声音刺激的等效激活发现，这些发现进一步阐明了新生儿大脑的功能组织。
