Neural Bases of Lexical Effects

词汇效果的神经基础

• 批准号: 6737865
• 负责人: Emily B Myers
• 金额: $ 2.72万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6737865
• 关键词: behavioral /social science research tag; bioimaging /biomedical imaging; cerebrovascular imaging /visualization; clinical research; functional magnetic resonance imaging; human subject; judgment; magnetic resonance imaging; neural information processing; phonology; predoctoral investigator; speech recognition

DESCRIPTION (provided by applicant): The goal of this research is to investigate the neural basis of lexical effects on the identification of phonetic categories. This will be accomplished by using functional magnetic resonance imaging (fMRI) in normal subjects as they make phonetic judgments to acoustic tokens which vary in both their degree of phonetic ambiguity as well as their lexical status. This research is expected to elucidate two general issues. First, what are the neural mechanisms which underlie perception of phonetic categories, and second, to what extent do top-down effects of lexical status influence those mechanisms. Experiments will use event-related fMRI, which obviates the need to block stimuli, and a sparse-sampling scanning technique, which allows for the presentation of acoustic tokens in relative silence. It is hypothesized that effects of lexical status on judgments of phoneme identity can be seen at perceptual stages of the speech processing stream, supporting an integrative, connectionist model of lexical processing in which upper levels of processing directly influence perception at lower levels. It is also hypothesized that differential patterns of modulation of activation will emerge in the left superior temporal gyrus, the left inferior temporal gyrus and anterior cingulate as a function of both stimulus uncertainty and lexical status. A discovery of brain areas which show modulation of activation due to top-down effects may shed light on the nature of language deficits in aphasic patients who have lesions in these areas.

描述（申请人提供）：本研究的目的是探讨词汇效应对语音类别识别的神经基础。这将通过使用功能性磁共振成像（fMRI）在正常受试者，因为他们作出语音判断的声学标记，这在他们的语音歧义程度以及他们的词汇状态。这项研究预计将阐明两个一般性问题。首先，是什么神经机制的语音类别的感知，第二，在何种程度上做自上而下的词汇地位的影响这些机制。实验将使用与事件相关的功能性磁共振成像，这避免了需要阻止刺激，和一个稀疏采样扫描技术，这允许在相对沉默的声音令牌的介绍。据推测，可以看出，在语音处理流的感知阶段的音素身份的判断词汇状态的影响，支持一个综合的，连接主义的词汇处理模型，在该模型中，上层处理直接影响感知在较低的水平。我们还假设，激活调制的差异模式将出现在左上级颞回，左颞下回和前扣带回作为刺激的不确定性和词汇状态的函数。由于自上而下的效应，大脑区域显示出激活的调制，这一发现可能会揭示失语症患者在这些区域有病变的语言缺陷的性质。