Development of Hemispheric Specialization for Lexical Pitch-Accent in Japanese Infants
Development of Hemispheric Specialization for Lexical Pitch-Accent in Japanese Infants
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DOI：
10.1162/jocn.2009.21377
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发表时间：
2010-11-01
影响因子：
3.2
通讯作者：
Mazuka, Reiko
中科院分区：
文献类型：
--
作者：
Sato, Yutaka;Sogabe, Yuko;Mazuka, Reiko
婴儿的语言感知能力在一岁内发生变化，从广泛的敏感性到广泛的语言对比，再到更好地适应母语。然而，目前尚不清楚的是，这种感知变化如何与大脑对母语对比的反应有关，即左右半球的功能专业化。在这里，为了阐明伴随这种感知变化的功能偏侧化的发展变化，我们进行了两个实验对日本婴儿使用日本词汇音高口音，改变单词的意义与音高模式的话。在第一个行为实验中，使用视觉习惯化，我们证实了口音模式的变化嵌入在双音节词。在第二个实验中，近红外光谱被用来测量皮质血流动力学反应的左右半球相同的词汇音高重音模式的变化和他们的纯音对应。我们发现，4个月和10个月大的婴儿对单词中音高变化的大脑反应在功能侧化方面有所不同：只有10个月大的婴儿才能看到左半球对单词中音高变化的感知优势。这些结果表明，日语词汇音高重音的知觉变化可能与功能侧化从双侧向左半球优势的转变有关。
Infants' speech perception abilities change through the first year of life, from broad sensitivity to a wide range of speech contrasts to becoming more finely attuned to their native language. What remains unclear, however, is how this perceptual change relates to brain responses to native language contrasts in terms of the functional specialization of the left and right hemispheres. Here, to elucidate the developmental changes in functional lateralization accompanying this perceptual change, we conducted two experiments on Japanese infants using Japanese lexical pitch-accent, which changes word meanings with the pitch pattern within words. In the first behavioral experiment, using visual habituation, we confirmed that accent pattern change embedded in disyllabic words. In the second experiment, near-infrared spectroscopy was used to measure cortical hemodynamic responses in the left and right hemispheres to the same lexical pitch-accent pattern changes and their pure tone counterparts. We found that brain responses to the pitch change within words differed between 4- and 10-month-old infants in terms of functional lateralization: Left hemisphere dominance for the perception of the pitch change embedded in words was seen only in the 10-month-olds. These results suggest that the perceptual change in Japanese lexical pitch-accent may be related to a shift in functional lateralization from bilateral to left hemisphere dominance.