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Categorical perception mechanism in the auditory cortex and its plasticity

听觉皮层的分类感知机制及其可塑性

基本信息

批准号：
09470370
负责人：
NAITO Yasushi
金额：
$ 3.84万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09470370/
关键词：
Auditory language Categorical perception Postron emission tomography plasticity Hearing loss Cochlear implant Speech coding Coarse coding 時間情報臨界期

项目摘要

Based on PET (positron emission tomography) findings on central mechanisms for spoken language processing in normal hearing subjects, those with inner ear hearing loss and in profoundly deaf cochlear implant (CI) users, it has been suggested that the neuronal networks for categorical perception in the auditory cortex may be located in the mid portion of the superior and middle temporal cortex. Perception of distorted and incomplete speech signals coded by cochlear implant may require excessive activity of speech processing networks, and the mid portion of the middle temporal gyrus, that is strongly activated under such condition, may play an important role in categorical perception. It was reported that the excitatory responses of neurons in the middle temporal gyrus had no close links to certain phonemic or prosodic features, and the degraded and incomplete speech signals may be recognized as speech on the basis of coarse coding, in which a profile of responses from a population of co … More arsely tuned units accurately specify a value. A coarse coding strategy may require extensive recruitment of neurons in the auditory cortex during processing degraded and ambiguous acoustic stimuli, which possibly underlie strong speech activation of the temporal cortex in CI users. Under such condition, the Broca's area and the supplementary motor area (SMA) exhibited strong speech activation. The SMA is a higher-order motor area and is known to be activated by pure internal rehearsal of motor sequences. This area is connected by long tracts with Broca's area, and is commonly activated when establishing programs for motor sequences including speech and daily skills. Broca's area has connections with the auditory association area via the arcuate fascicles. A hypothetical microcircuit consisting of the SMA, Broca's area and the auditory association area is supposed to establish working memory for language decoding and encoding, enabling the brain to maintain an internal copy of the original auditory message. Such an internal playback mechanism might be activated more to accomplish accurate categorical perception of incomplete speech signals, recognizing phonemes or words coded by damaged inner ear or by CI is often difficult, and requires comparison of the heard message several times with the stored versions of similar words. More studies focused on the functional anatomy of each area are necessary to verify this hypothesis. Less

基于PET（正电子发射断层扫描）对听力正常者、内耳听力损失者和极聋人工耳蜗植入者的口语加工中枢机制的研究结果，提出听觉皮层中分类知觉的神经元网络可能位于上级和中颞叶皮层的中部。对人工耳蜗编码的失真和不完整的语音信号的感知可能需要语音处理网络的过度活动，在这种情况下强烈激活的颞中回中部可能在分类感知中起重要作用。已有研究表明，颞中回神经元的兴奋性反应与某些音位或韵律特征没有密切联系，退化和不完整的语音信号可以在粗编码的基础上被识别为语音，在粗编码中，来自一个群体的反应轮廓可以被识别为语音。 ...更多信息粗调单元精确地指定一个值。粗编码策略可能需要在处理退化和模糊的声刺激过程中广泛招募听觉皮层中的神经元，这可能是CI用户颞叶皮层的强烈语音激活的基础。在这种条件下，Broca区和辅助运动区（SMA）表现出较强的言语激活。SMA是一个高阶运动区，并且已知由运动序列的纯内部排练激活。这个区域与布罗卡区有很长的联系，通常在建立包括语言和日常技能在内的运动序列程序时被激活。布罗卡区与听觉联合区之间通过弓状神经束有联系。一个假设的微回路由SMA，布罗卡区和听觉关联区组成，应该建立语言解码和编码的工作记忆，使大脑能够保持原始听觉信息的内部副本。这种内部回放机制可能会被更多地激活，以实现对不完整语音信号的准确分类感知，识别由受损的内耳或CI编码的音素或单词通常很困难，并且需要将听到的消息与存储的版本进行多次比较类似的话。更多的研究集中在每个区域的功能解剖是必要的，以验证这一假设。少