Neural Basis of Lexical and Speech Processing

词汇和语音处理的神经基础

基本信息

批准号：
6898833
负责人：
Sheila E Blumstein
金额：
$ 34.84万
依托单位：
BROWN UNIVERSITY
依托单位国家：
美国
项目类别：
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

项目摘要

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（由申请人提供）：这项研究的目的是了解如何使用与事件相关的功能磁共振成像（fMRI）的语音 - 循环处理系统映射到其基础神经系统的功能结构。将研究两个假设，既探讨了听觉语音和词汇处理的计算特性的基础神经系统。第一个假设探讨了两个半球的计算机制是否优先处理语音信号的不同特性。一系列使用语音歧视和语音分类任务的实验将检查辅音和元音感知的基础的许多声音 - 表达参数，包括辅音感知的语音发作时间和共振剂频率持续时间，以及持续时间和持久性和共振剂频率（F L-F2）空间中的载体。假设，与左半球相对应的声学特性将优先处理，无论其声学作用在语言处理中起着功能性的作用而不论其声学结构如何。相反，假设右半球的激活将由语音信号的固有声学特性调节。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其神经底物。假设在语音表达，词语和/或语义竞争的条件下，将增加左额激活。语音竞争将通过探索声音 - 语音结构以及典范与对比鲜明的距离的距离以及竞争性语音类别影响额叶激活的程度进行研究。词汇竞争将通过探索语音因素对词汇竞争和语音因素对词汇邻域密度的影响进行研究。语义竞争将通过探索语义上模棱两可的单词与明确的单词对神经激活模式相比的影响进行研究。