Neural Dynamics of Spoken Word Recognition

描述（由申请人提供）：大脑和认知科学的研究提供了压倒性的证据，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）的相互作用。这些相互作用是显著的，因为它们似乎允许听众，包括许多脑区域有局灶性损伤的中风患者，这些脑区域负责表示这些类型的信息，识别口语，即使当语音由于清晰度差、语音合成不完善、嘈杂环境或由于数字减少或滤波导致的信号质量差而不清楚时（例如，当通过人工耳蜗植入、助听器或电话连接不良时）。由于当前行为和单峰成像范式的可解释性的内在局限性，这些相互作用的本质或必要性仍然存在激烈的争论。该提案通过整合MRI、MEG和EEG数据来解决这些限制，以提供在语音感知任务期间不断发展的大脑激活的高时空分辨率图像。这些数据将提交给格兰杰因果分析，这使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关系的因果模式。运用这些技术，本研究探讨了产生以下机制：（1）言语声音的离散分类（分类感知），（2）频率或语音定向对言语声音感知的影响，（3）语义语境对言语感知的影响。在确定了局部功能如何相互作用，以产生强大的语音感知未受损的听众，这些工具将被转向研究如何保存的过程中进行重组和整合后，在18个月的单侧局灶性脑损伤中风后，让失语症患者的功能恢复。这些数据解决了关于大脑功能、人类语音感知的鲁棒性以及支持失语症患者恢复的机制的中心问题，这些问题以前无法解决。作为基础研究，这项工作应该对研究、评估和局部损伤患者的康复具有广泛的意义。 公共卫生相关性：失语症是一种常见的神经系统疾病，影响大约100万美国人使用语言进行交流的能力（国家耳聋和其他交流障碍研究所，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期间表现出不同水平的功能恢复相关和新的大脑激活模式（Heiss & Thiel，2006）。拟议的工作将描述未受损的听众大脑活动的相互作用模式，并研究这些激活模式如何与保留的大脑功能相结合，以随着时间的推移改善失语症患者的语言理解。

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.