Timing and neural bases of complex word recognition: electrophysiological studies

描述（由申请人提供）：了解认知过程和大脑机制，词汇是存储和检索从心理词典是至关重要的，我们了解语言是如何组织在人类大脑。然而，这一进程的基本方面仍不清楚。一个主要的争论是关于像“茶杯”这样的复杂单词是否是以称为词素的较小部分（茶/杯）来存储和检索的，或者是否所有的单词都被视为整个词块。由于这些观点对单词表征的性质做出了根本不同的预测，因此研究复杂的单词变得至关重要。该项目涉及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，允许在任何明显的判断（如反应时间）之前实时测量文字识别的阶段及其大脑水平的实例化。利用这些对时间敏感的大脑水平测量提供了一种新的方法来研究心理词典是否涉及内部结构化表征，时间过程和对它们分解的限制，以及什么皮层机制有助于这些计算。具体来说，复杂的文字处理的时间和神经基础将检查利用复合词的特定语言学特性，允许仔细操纵的变量，可能会限制分解，在检查时，很难或不可能的方式附加（如过去时态）的话只。确定大脑最初是否处理两个已知的复杂单词（例如，“tegram”）和可能具有有意义的词部分的新颖词（例如“drugrack”），将告知我们对有意义的词部分或整个词是词识别中的基本表示单位的理解。此外，测量大脑对具有相对透明的意义关系的复合词（例如“tebalion”）和那些没有意义关系的复合词（如“honeymoon”）的反应，提供了一个直接的测试，可以测试单词是否、何时以及用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了独立于单词形式和单词意义的基本水平的单词表征。开发一个更全面的文字阅读神经认知模型对解决涉及文字识别和阅读缺陷的语言障碍的范围具有直接的健康相关影响，包括阅读障碍、特定语言障碍、失语症和阿尔茨海默氏病，增加了为这些缺陷确定新治疗方法的可能性，其中许多缺陷涉及普遍但知之甚少的文字部分问题。此外，开发的MEG测定可提供用于诊断和直接测量临床干预中治疗的脑水平效应的灵敏的新工具。本研究旨在探讨复杂字词阅读的本质与皮质机制。更好地理解单词阅读中的基本认知过程对我们理解语言障碍有直接影响，对于语言障碍，复杂单词的阅读提出了基本的，但仍然知之甚少的挑战，包括阅读障碍，特定语言障碍，与中风和脑创伤相关的障碍，以及包括阿尔茨海默病和帕金森病在内的疾病。这两个发现和创新的大脑水平的视觉文字识别的测量在这个项目中开发的应用，这些疾病的表征，诊断和补救的直接潜力。

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.