Neural Dynamics of Spoken Word Recognition

描述(申请人提供)：大脑和认知科学的研究提供了压倒性的证据，表明即使是看似简单的任务，如理解口语单词，也依赖于各种不同类型的信息(例如，听觉、语音、语音、词汇、语义等)的交互作用。这些交互作用的显著之处在于，它们似乎允许听者，包括许多中风患者，在负责代表这些类型的信息的大脑区域受到局灶性损伤，即使在由于发音不佳、语音合成不完善、噪声环境或由于数字减少或过滤而导致的信号质量差(例如，通过人工耳蜗植入、助听器或电话连接不良而经历)而导致语音不清楚的情况下，也能够识别口语。由于当前行为成像和单峰成像范式的可解释性的内在局限性，许多这种相互作用的性质或必要性仍然存在激烈的争论。这项建议通过整合MRI、MEG和EEG数据来解决这些限制，以提供在语音感知任务中进化的大脑激活的高时空分辨率图像。这些数据将被提交给格兰杰因果分析，这使得研究人员能够直接检查与处理特定类型信息相关的不同大脑区域激活之间的因果关系模式。通过使用这些技术，本研究考察了以下机制：(1)语音的离散分类(范畴知觉)，(2)频率或音位效应对语音知觉的影响，(3)语义语境对言语知觉的影响。在确定了局部功能如何相互作用以在未受损的听者中产生强大的言语感知后，这些工具将被用于研究中风后18个月内单侧局灶性脑损伤后保留的过程是如何重组和整合的，以使失语症患者的功能恢复。这些数据解决了关于大脑功能、人类语言感知的稳健性以及支持失语症患者康复的机制的核心问题，这些问题以前是无法解决的。作为基础研究，这项工作应该对局灶性损伤患者的研究、评估和康复具有广泛的影响。 公共卫生相关性：失语症是一种常见的神经疾病，影响大约100万美国人使用语言进行交流的能力(国家耳聋和其他沟通障碍研究所，1997)。尽管失语症通常是不可逆的脑损伤的结果，但失语症患者在语言任务中表现出不同程度的功能恢复和新的大脑激活模式(Heiss&Thiel，2006)。这项拟议的工作将描述未受损的听者大脑活动的相互作用模式，并研究这些激活模式如何与失语症患者保留的大脑功能相结合，从而随着时间的推移改善语言理解。

DESCRIPTION (provided by applicant): Research in the brain and cognitive sciences provides overwhelming evidence that even seemingly simple tasks like understanding spoken words rely on the interaction of a variety different types of information (e.g. auditory, phonetic, phonological, lexical, semantic etc.). These interactions are remarkable in that they appear to allow listeners, including many stroke patients with focal damage to brain regions that are responsible representing these types of information, to recognize spoken language, even when speech is unclear due to poor articulation, imperfect speech synthesis, noisy environments, or poor signal quality due to digital reduction or filtering (e.g. when experienced via cochlear implant, hearing aids, or a poor phone connection). There is still vigorous debate about the nature or necessity of many of these interactions due to intrinsic limitations in the interpretability of current behavioral and unimodal imaging paradigms. This proposal addresses these limitations by integrating MRI, MEG and EEG data to provide high spatiotemporal resolution images of evolving brain activation during speech perception tasks. These data will be submitted to Granger causality analysis, which allows researchers to directly examine patterns of cause and effect in the relationship between activation of different brain regions associated with the processing of specific types of information. Using these techniques, the proposed research examines the mechanisms that give rise to: (1) the discrete categorization of speech sounds (categorical perception), (2) frequency or phonotactic effects on the perception of speech sounds, (3) the influence of semantic context on speech perception. Having identified how localized functions interact to produce robust speech perception in unimpaired listeners, these tools will then be turned to examine how preserved processes are reorganized and integrated after unilateral focal brain damage in the 18 months following stroke, to allow the recovery of function in aphasic patients. These data address central, previously irresolvable questions about brain function, the robustness of human speech perception, and the mechanisms that support recovery in aphasic patients. As basic research, the work should have wide-reaching implications for the study, assessment, and rehabilitation of patients with focal damage. PUBLIC HEALTH RELEVANCE: Aphasia is a common neurological condition affecting the ability of roughly one million Americans to communicate using language (National Institute on Deafness and Other Communication Disorders, 1997). Despite the fact that aphasia is generally the result of irreversible brain damage, aphasics show differing levels of functional recovery associated and new patterns of brain activation during language tasks (Heiss & Thiel, 2006). The proposed work will characterize patterns of interaction in brain activity in unimpaired listeners and examine how these patterns of activation are integrated with preserved brain function to produce improved language understanding over time in people with aphasia.