Statistical segmentation of tone sequences activates the left inferior frontal cortex: A near-infrared spectroscopy study
Statistical segmentation of tone sequences activates the left inferior frontal cortex: A near-infrared spectroscopy study
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DOI：
10.1016/j.neuropsychologia.2008.05.012
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发表时间：
2008-09-01
期刊：
影响因子：
2.6
通讯作者：
Okanoya, Kazuo
中科院分区：
文献类型：
--
作者：
Abla, Dilshat;Okanoya, Kazuo
词汇切分，即发现嵌入连续语音流中的单词之间的边界，是语言学习者的一项重要能力；人类部分通过计算语音之间的转换概率来完成这一任务。行为学和事件相关电位（ERP）研究表明，对顺序概率（统计学习）的检测在词汇切分过程中起着重要作用。为了确定在声调序列的统计切分过程中起作用的大脑区域，我们在参与者接触连续的、非语言的听觉序列时，使用多通道近红外光谱（NIRS）测量了血氧变化，这些听觉序列的元素被组织成固定的“声调词”，但以随机顺序排列。我们通过在呈现连续声调序列之前的训练阶段呈现刺激，使参与者习惯这些声调词。训练后，在近红外光谱记录期间，包含六个声调词的统计序列和包含11个随机排列声调的随机序列交替呈现。在统计序列条件下，观察到左侧额下回（IFC）的氧合血红蛋白浓度大幅增加，但在随机序列条件下没有。这表明左侧额下回在声调序列的统计切分中起着重要作用，在此过程中，参与者将在训练阶段获得的知识应用于后续的连续序列。（C）2008爱思唯尔有限公司。保留所有权利。
Word segmentation, that is, discovering the boundaries between words that are embedded in a continuous speech stream, is an important faculty for language learners; humans solve this task partly by calculating transitional probabilities between sounds. Behavioral and ERP studies suggest that detection of sequential probabilities (statistical learning) plays an important role in the process of word segmentation. To identify the brain regions that are engaged during statistical segmentation of tone sequences, we measured changes in blood oxygenation using multichannel near-infrared spectroscopy (NIRS) while participants were exposed to continuous, nonlinguistic auditory sequences, the elements of which were organized into fixed "tone-words," but sequenced in random order. We habituated the participants to the tone-words by presenting the stimuli in a training phase prior to the presentation of the continuous tone sequences. After training, the statistical sequences, which included six tone-words, and the random sequences, which included 11 tones in random order, were presented alternately during NIRS recording. A large increase in the oxygenated hemoglobin concentration was observed in the left inferior frontal cortex (IFC) during the statistical sequence condition, but not during the random sequence condition. This suggests that the left IFC plays an important role in statistical segmentation of tone sequences, during which participants deploy the knowledge obtained in the training phase on the subsequent continuous sequence. (C) 2008 Elsevier Ltd. All rights reserved.