Neural attunement processes in infants during the acquisition of a language-specific phonemic contrast
Neural attunement processes in infants during the acquisition of a language-specific phonemic contrast
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DOI：
10.1523/jneurosci.1984-06.2007
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发表时间：
2007-01-10
影响因子：
5.3
通讯作者：
Kojima, Shozo
中科院分区：
文献类型：
--
作者：
Minagawa-Kawai, Yasuyo;Mori, Koichi;Kojima, Shozo
为了阐明特定语言音素库中的发育神经调谐过程，使用近红外光谱技术测量了日语婴儿对持续元音对比的脑血流动力学反应。因为只有相对时长信息才能区分这种特殊的元音对比，所以第一语言学习者和第二语言学习者都很难获得这种在语音上至关重要的时长差异。以前对成年人进行的跨语言研究表明，只有母语为日语的人才能观察到音素特定的、左倾占优势的神经反应。使用相同的刺激，我们发现，在6到7个月龄组中，对跨类别变化的反应比对类别内变化的反应更大，然后在12个月以上的组中稳定下来。然而，只有在13个月及以上的组中，才能观察到听觉区域音素特异性反应的左侧优势。因此，作为早期听觉经验的结果，持续音素对比很可能是在6-7个月时由普通听觉回路首先处理的。12个月后，对比的神经处理被切换到更多的语言回路，这一次是类似于本土成年听众的左侧优势。
To elucidate the developmental neural attunement process in the language-specific phonemic repertoire, cerebral hemodynamic responses to a Japanese durational vowel contrast were measured in Japanese infants using near-infrared spectroscopy. Because only relative durational information distinguishes this particular vowel contrast, both first and second language learners have difficulties in acquiring this phonemically crucial durational difference. Previous cross-linguistic studies conducted on adults showed that phoneme-specific, left-dominant neural responses were observed only for native Japanese listeners. Using the same stimuli, we show that a larger response to the across-category changes than to the within-category changes occurred transiently in the 6- to 7-month-old group before stabilizing in the groups older than 12 months. However, the left dominance of the phoneme-specific response in the auditory area was observed only in the groups of 13 months and above. Thus, the durational phonemic contrast is most likely processed first by a generic auditory circuit at 6- 7 months as a result of early auditory experience. The neural processing of the contrast is then switched over to a more linguistic circuit after 12 months, this time with a left dominance similar to native adult listeners.