Neural Bases of Lexical Effects

词汇效果的神经基础

• 批准号: 6799596
• 负责人: Emily B Myers
• 金额: $ 2.8万
• 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/6799596
• 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（由申请人提供）：本研究旨在探讨词汇对语音类别识别影响的神经基础。这将通过在正常受试者中使用功能性磁共振成像（fMRI）来完成，因为他们对语音标记进行语音判断，这些声学标记在语音歧义程度和词汇状态上都有所不同。本研究旨在阐明两个一般性问题。首先，语音类别感知的神经机制是什么；其次，词汇状态自上而下的影响在多大程度上影响了这些机制。实验将使用与事件相关的功能磁共振成像（fMRI），它避免了阻断刺激的需要，以及稀疏采样扫描技术，它允许在相对沉默的情况下呈现声音标记。假设词汇状态对音素同一性判断的影响可以在语音加工流的知觉阶段看到，支持词汇加工的综合连接主义模型，在该模型中，较高水平的加工直接影响较低水平的知觉。我们还假设，在刺激不确定性和词汇状态下，左侧颞上回、左侧颞下回和前扣带中会出现不同的激活调节模式。一项发现表明，由于自上而下的影响，大脑区域的激活被调节，这可能会揭示在这些区域有损伤的失语症患者的语言缺陷的本质。