Timing and neural bases of complex word recognition: electrophysiological studies

描述（由申请人提供）：了解词汇存储和检索的认知过程和大脑机制对我们理解人类大脑中语言的组织方式至关重要。然而，这一进程的基本方面仍不清楚。一个主要的争论是，像“茶杯”这样的复杂单词是按照被称为语素（tea/cup）的更小的部分来存储和检索的，还是所有的单词都被当作完整的单词块来对待。由于这些观点对单词表征的本质做出了截然不同的预测，因此研究复杂单词变得至关重要。这个项目包括在复杂的文字处理过程中使用高时间分辨率脑磁图（MEG）记录大脑活动，允许在任何公开的判断（如反应时间）之前，实时测量单词识别的阶段及其大脑层面的实例化。利用这些时间敏感的大脑水平测量为研究心理词汇是否涉及内部结构表征、它们分解的时间过程和限制，以及支持这些计算的皮层机制提供了一种新的方法。具体来说，复杂文字处理的时间和神经基础将通过利用复合词的特定语言特性进行检查，允许仔细操纵可能限制分解的变量，以仅在检查固定（例如过去时）单词时难以或不可能的方式。确定大脑最初是否同时处理已知的复杂单词（如“茶杯”）和可能包含有意义的单词部分的新单词（如“茶杯”）。“药品”)，这将告诉我们，在单词识别中，有意义的单词部分还是整个单词是基本的表征单位。此外，测量大脑对具有相对透明意义关系的复合词的反应(例如：（如“茶杯”）和那些没有的（如“蜜月”），提供了一个直接的测试，以确定单词是否，何时以及以什么样的潜在神经机制被识别，特别是有意义的单词部分是否构成独立于单词形式和单词含义水平的单词表征的基本水平。开发一个更完整的单词阅读神经认知模型对解决包括单词识别和阅读缺陷在内的语言障碍具有直接的健康影响，包括阅读障碍，特殊语言障碍，失语症和阿尔茨海默病，增加了识别这些缺陷的新治疗方法的潜力，其中许多涉及普遍存在但知之甚少的单词部分问题。此外，开发的脑磁图分析可能为诊断和直接测量临床干预治疗的脑水平效应提供敏感的新工具。本研究项目探讨复杂词汇阅读的本质和皮层机制。更好地理解单词阅读的基本认知过程对我们对语言障碍的理解有直接的影响，对于复杂单词的阅读是基本的，尽管仍然知之甚少的挑战，包括阅读障碍，特定语言障碍，与中风和脑外伤相关的障碍，以及包括阿尔茨海默病和帕金森病在内的疾病。研究结果和在这个项目中开发的视觉单词识别的创新脑水平测量都有直接应用于这些疾病的表征、诊断和补救的潜力。

DESCRIPTION (provided by applicant): Understanding the cognitive processes and brain mechanisms with which words are stored and retrieved from the mental lexicon is critical to our understanding of how language is organized in the human brain. Fundamental aspects of this process, however, remain unclear. A major debate concerns whether complex words like 'teacup' are stored and retrieved in terms of smaller parts called morphemes (tea/cup), or whether all words are treated alike as whole-word chunks. As these views make fundamentally distinct predictions regarding the nature of word representations, investigating complex words becomes crucial. This project involves recording brain activity using high temporal resolution magnetoencephalography (MEG) during complex word processing, allowing real-time measurement of the stages of word recognition and their brain- level instantiation, prior to any overt judgment such as reaction time. Utilizing these time-sensitive brain-level measurements provides a new way forward in investigating whether the mental lexicon involves internally- structured representations, the time course and constraints on their decomposition, and what cortical mechanisms subserve these computations. Specifically, the timing and neural bases of complex word processing will be examined by taking advantage of the specific linguistic properties of compound words, allowing careful manipulation of variables that may constrain decomposition, in ways difficult or impossible when examining affixed (e.g. past-tense) words only. Establishing whether the brain initially processes both known complex words (e.g., 'teacup') and novel words which may have meaningful word parts (e.g. 'drugrack') in terms of those meaningful word parts will inform our understanding of whether the meaningful word part or the whole-word is the basic unit of representation in word recognition. Further, measuring brain responses to compound words with relatively transparent meaning relations (e.g. 'teacup') and those without (like 'honeymoon'), provides a direct test of whether, when, and with what underlying neural mechanisms words are recognized, and in particular whether meaningful word parts constitute a fundamental level of word representation independent of the levels of word form and word meaning. Developing a fuller neurocognitive model of word reading has direct health-related impact for addressing the range of language disorders involving word recognition and reading deficits, including dyslexia, Specific Language Impairment, aphasias, and Alzheimer's disease, increasing the potential for identifying new treatments for these deficits, many of which involve pervasive yet poorly understood problems with word parts. Further, the MEG assays developed may provide sensitive new tools for diagnosing and directly measuring brain-level effects of therapy in clinical intervention. This research project investigates the nature and cortical mechanisms underlying the reading of complex words. Better understanding the basic cognitive processes in word reading has direct impact for our understanding of language disorders, for which the reading of complex words presents fundamental, though still poorly understood challenges, including dyslexia, Specific Language Impairment, disorders associated with stroke and brain trauma, and diseases including Alzheimer's Disease and Parkinson's Disease. Both the findings and the innovative brain-level measurements of visual word recognition developed in this project have direct potential for application to the characterization, diagnosis, and remediation of these disorders.