Characterizing the temporal processing of speech in the human auditory cortex

项目摘要 时间是声音的基本维度，因此时间整合是语音感知的基础。 为了识别一个复杂的结构，比如流利的语音中的一个单词，大脑必须整合许多不同的信息。 时间跨度从几十毫秒到几百毫秒。这些时间尺度比 听觉神经反应的持续时间。因此，听觉皮层必须整合声学信息 来编码语言单位。另一方面，中间单元的性质 声音和意义之间的关系仍然存在争议。局部脑损伤显示出选择性 所有级别的语言处理（音素、音素定位和语义）都有障碍，但目前的模型 口语单词识别不同意这些表征水平的存在和类型。的神经基础 时间和语言处理仍然是推测性的，部分原因是有限的时空分辨率， 非侵入性的人类神经成像技术，这是研究流利语音编码所需的。我们的多- PI提案通过组建一个研究人员和临床医生团队来克服这些挑战， 纽约大学和哥伦比亚大学的互补专业知识。我们建议从大量的 这提供了一个罕见的和独特的机会，收集直接的皮层记录， 几个听觉区域我们提出了新的实验范式和分析方法， 何时以及如何随着时间的推移整合语音的声学特征以对语言单位进行编码。我们的实验 范式将决定刺激整合期的功能和解剖组织在小学 和非初级听觉皮层区域，并将这些区域的时间处理与出现联系起来， 音位、音位和语义层面的表征。最后，我们将确定非线性 使听觉皮层能够在长时间内整合快速特征的计算机制， 在语音识别中至关重要。小学生和初中生对言语时间加工的理解 非初级听觉皮层对于开发人脑中的语音感知的完整模型是至关重要的， 这对于理解这些过程在言语和交流障碍中是如何分解的至关重要。

Project Summary Time is the fundamental dimension of sound, and temporal integration is thus fundamental to speech perception. To recognize a complex structure such as a word in fluent speech, the brain must integrate across many different timescales spanning tens to hundreds of milliseconds. These timescales are considerably longer than the duration of responses at the auditory nerve. Therefore, the auditory cortex must integrate acoustic information over long and varied timescales to encode linguistic units. On the other hand, the nature of the intermediate units of representation between sound and meaning remains debated. Focal brain injuries have shown selective impairment at all levels of linguistic processing (phonemic, phonotactic, and semantic) but current models of spoken word recognition disagree on the existence and type of these representational levels. The neural basis of temporal and linguistic processing remains speculative partly due to the limited spatiotemporal resolution of noninvasive human neuroimaging techniques which is needed to study the encoding of fluent speech. Our multi- PI proposal overcomes these challenges by assembling a team of researchers and clinicians with complementary expertise at NYU and Columbia University. We propose to record invasively from a large number of neurosurgical patients, which provides a rare and unique opportunity to collect direct cortical recordings across several auditory regions. We propose novel experimental paradigms and analysis methods to investigate where, when, and how acoustic features of speech are integrated over time to encode linguistic units. Our experimental paradigms will determine the functional and anatomical organization of stimulus integration periods in primary and nonprimary auditory cortical regions and relate the temporal processing in these regions to the emergence of phonemic-, phonotactic-, and semantic-level representations. Finally, we will determine the nonlinear computational mechanisms that enable the auditory cortex to integrate fast features over long durations, which is essential in speech recognition. Understanding of the temporal processing of speech in primary and nonprimary auditory cortex is critical for developing complete models of speech perception in the human brain, which is essential to understanding of how these processes break down in speech and communication disorders.