Longy School of Music of Bard College, 27 Garden Street, Cambridge, MA 02138, United States.
Center for Evolutionary Cognitive Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Cereb Cortex. 2024 Apr 1;34(4). doi: 10.1093/cercor/bhae124.
This study investigates neural processes in infant speech processing, with a focus on left frontal brain regions and hemispheric lateralization in Mandarin-speaking infants' acquisition of native tonal categories. We tested 2- to 6-month-old Mandarin learners to explore age-related improvements in tone discrimination, the role of inferior frontal regions in abstract speech category representation, and left hemisphere lateralization during tone processing. Using a block design, we presented four Mandarin tones via [ta] and measured oxygenated hemoglobin concentration with functional near-infrared spectroscopy. Results showed age-related improvements in tone discrimination, greater involvement of frontal regions in older infants indicating abstract tonal representation development and increased bilateral activation mirroring native adult Mandarin speakers. These findings contribute to our broader understanding of the relationship between native speech acquisition and infant brain development during the critical period of early language learning.
本研究调查了婴儿言语处理中的神经过程，重点关注左额区和普通话婴儿在获得母语声调范畴时的大脑半球偏侧化。我们测试了 2 至 6 个月大的普通话学习者，以探讨年龄相关的声调辨别能力的提高、下额叶区域在抽象言语范畴表示中的作用，以及在声调处理过程中的左半球偏侧化。我们使用块设计，通过 [ta] 呈现了四个普通话声调，并使用功能近红外光谱测量了含氧血红蛋白浓度。结果表明，随着年龄的增长，声调辨别能力有所提高，年龄较大的婴儿中额区的参与度更高，表明抽象声调表示的发展以及双侧激活的增加，与母语普通话使用者相匹配。这些发现有助于我们更深入地了解母语习得与早期语言学习关键期婴儿大脑发育之间的关系。
