Neural Basis of Lexical and Speech Processing

词汇和语音处理的神经基础

• 批准号: 6771643
• 负责人: Sheila E Blumstein
• 金额: $ 34.51万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6771643
• 关键词: auditory stimulus; behavioral /social science research tag; blood flow measurement; brain electrical activity; cerebral dominance; clinical research; decision making; frontal lobe /cortex; functional magnetic resonance imaging; human subject; interview; neural information processing; neural transmission; neuroanatomy; phonology; semantics; sensory discrimination; sound perception; speech recognition; vocabulary; young adult human (21-34)

DESCRIPTION (provided by applicant): The goal of this research is to understand how the functional architecture of the speech-lexical processing system maps on to the neural systems underlying it using event-related functional magnetic resonance imaging (fMRI). Two hypotheses will be investigated, both exploring the neural systems underlying the computational properties of auditory speech and lexical processing. The first hypothesis explores whether the computational mechanisms of the two hemispheres preferentially process different properties of the speech signal. A series of experiments using both speech discrimination and phonetic categorization tasks will examine a number of acoustic-phonetic parameters underlying both consonant and vowel perception including voice-onset time and formant frequency duration in the perception of consonants, and duration and formant frequency (F l-F2) space in the perception of vowels. It is hypothesized that the acoustic properties corresponding to the phonetic categories of speech will be preferentially processed by the left hemisphere irrespective of their acoustic structure owing to the functional role that sound structure plays in language processing. In contrast, it is hypothesized that activation of the right hemisphere will be modulated by the inherent acoustic properties of the speech signal. The second hypothesis explores how the computational properties of the speech lexical processing system map on to its neural substrate. It is hypothesized that there will be increased left frontal activation under conditions of phonetic-phonological, lexical, and/or semantic competition. Phonetic competition will be investigated by exploring the extent to which acoustic-phonetic structure and the proximity of an exemplar to a contrasting, and hence, competing phonetic category influences frontal activation. Lexical competition will be investigated by exploring the influence of phonetic factors on lexical competition and phonological factors on lexical neighborhood density. Semantic competition will be investigated by exploring the effects of semantically ambiguous words compared to unambiguous words on neural activation patterns.

描述(申请人提供)：这项研究的目标是了解语音-词汇处理系统的功能架构如何通过事件相关功能磁共振成像(FMRI)映射到其下的神经系统。将研究两个假设，都是探索听觉语音和词汇处理的计算特性背后的神经系统。第一个假设探索了两个半球的计算机制是否优先处理语音信号的不同性质。采用语音识别和语音分类任务的一系列实验将考察声母和元音感知的声学参数，包括辅音感知中的语音起始时间和共振峰频率持续时间，以及元音感知中的持续时间和共振峰频率(F L-F2)空间。由于声音结构在语言处理中所起的功能作用，假设与语音的语音类别相对应的声学特性将优先由左半球处理，而与其声学结构无关。相反，假设右半球的激活将由语音信号的固有声学属性来调制。第二个假设探讨了语音词汇处理系统的计算特性如何映射到它的神经底物上。假设在语音-语音、词汇和/或语义竞争的条件下，左额叶激活增加。语音竞争将通过探索声学-语音结构和样本与对比的接近程度来研究，因此，竞争的语音类别影响额叶激活。通过语音因素对词汇竞争的影响和语音因素对词汇邻域密度的影响来研究词汇竞争。语义竞争将通过探索语义模糊的词与无歧义的词对神经激活模式的影响来进行研究。