The perception of voice onset time: An fMRI investigation of phonetic category structure
The perception of voice onset time: An fMRI investigation of phonetic category structure
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DOI：
10.1162/0898929054985473
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发表时间：
2005-09-01
影响因子：
3.2
通讯作者：
Rissman, J
中科院分区：
文献类型：
--
作者：
Blumstein, SE;Myers, EB;Rissman, J
本研究通过考察语音分类任务中对语音起始时间（VOT）连续体的感知，探讨了语音类别结构感知的神经系统。刺激包括五个合成语音刺激，其VOT范围从0毫秒（[da]）到40毫秒（[ta]）。从12名受试者的结果表明，神经系统是敏感的VOT的差异为10毫秒，语音类别结构的细节保留在整个语音处理流。左额下回（IFG）和扣带回都表现出等级激活作为类别成员的函数，随着刺激接近语音类别边界，激活增加。这些结果是一致的，认为左IFG参与语音决策过程，与激活的程度的影响，增加资源致力于解决语音类别成员资格和/或竞争语音类别之间的选择。扣带回的激活模式表明，它是敏感的刺激困难和解决反应冲突。相反，左颞中回后部和左角回的激活只对语音类别的“最佳匹配”进行调制，这表明这些区域参与了将声音结构映射到其语音表征的过程。双侧上级颞回（STG）对语音范畴结构差异的敏感性较弱，进一步证明STG参与了语音感觉特性的早期分析。
This study explored the neural systems underlying the perception of phonetic category structure by investigating the perception of a voice onset time (VOT) continuum in a phonetic categorization task. Stimuli consisted of five synthetic speech stimuli which ranged in VOT from 0 msec ([da]) to 40 msec ([ta]). Results from 12 subjects showed that the neural system is sensitive to VOT differences of 10 msec and that details of phonetic category structure are retained throughout the phonetic processing stream. Both the left inferior frontal gyrus (IFG) and cingulate showed graded activation as a function of category membership with increasing activation as stimuli approached the phonetic category boundary. These results are consistent with the view that the left IFG is involved in phonetic decision processes, with the extent of activation influenced by increased resources devoted to resolving phonetic category membership and/or selecting between competing phonetic categories. Activation patterns in the cingulate suggest that it is sensitive to stimulus difficulty and resolving response conflict. in contrast, activation in the posterior left middle temporal gyrus and the left angular gyrus showed modulation of activation only to the "best fit" of the phonetic category, suggesting that these areas are involved in mapping sound structure to its phonetic representation. The superior temporal gyrus (STG) bilaterally showed weaker sensitivity to the differences in phonetic category structure, providing further evidence that the STG is involved in the early analysis of the sensory properties of speech.