Architecture and plasticity of auditory lexical representations in the human brain

考虑到地球仪语言的多样性和丰富性，语音感知可以说是人类大脑的主要成就之一。虽然现在认知神经科学家广泛支持皮层区域的层次结构有助于听觉和语音处理的概念，但对于不同的大脑区域在语音识别中扮演的角色，语音系统如何学习和表示口语单词，以及如何通过一种感觉（例如，通过阅读）可以允许大脑通过另一种感觉（例如，通过听力）。在国家科学基金会的支持下，我们将使用先进的功能性磁共振成像（fMRI）来研究这些问题。具体来说，该项目旨在解决一个主要的持续争议，关于如何以及在哪里的话是在大脑中表示的，第一次，应用功能磁共振成像技术，已成功地用于回答相关的问题，在该领域的书面文字。第二项研究将探索大脑如何学习新的口语单词并将其添加到听觉词典中。 在最后一组研究中，该项目将在我们对听觉和视觉系统如何在阅读中联系以及这种互动如何通过跨感官学习实现的理解中开辟新天地。理解语音处理的神经基础和语言的跨感官学习不仅对基础科学，而且对从教育和语言学习到工程学的其他领域都非常感兴趣（通过阐明用于深层多感官层次的有效学习算法，例如，用于自动语音识别）以及生物医学领域（通过建立一个研究一系列疾病的基础，包括阅读障碍和语言理解缺陷）。该研究项目将成为培养下一代科学家的机会，包括研究生、本科生和高中生。在更科学的细节，拟议的项目的总体目标是研究听觉词汇在人类大脑中的存在和可塑性，并了解耦合的书面和听觉言语表征，允许跨模态迁移的词汇学习。该项目有三个目标：目标1解决了目前的争议，关于听觉词表征在大脑中的存在和位置。我们以前开发的翻译技术，以确定一个“视觉词汇”在“视觉词形区”，我们将使用敏感的fMRI快速适应（fMRI-RA）和其他先进的功能磁共振成像技术来测试的假设（接受）听觉词汇类似的“听觉词形区”在左前上级颞叶皮层。在同一时间，我们将测试是否存在另一个词汇在电机相关的语音领域的听觉背流表示发音词的形式，自动激活的语音感知通过“逆模型”。目标2旨在探讨听觉词汇中加入新词所引起的可塑性。目的3研究书面语与听觉系统的相互作用。先前的研究表明，阅读激活了熟练读者的语音表征，这种语音编码对阅读习得至关重要。我们将测试新的假设，即书面文字引起听觉系统的广泛激活，以及对新的书面文字的培训可以驱动听觉词汇系统中的单词选择性重新布线。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Considering the diversity and richness of languages spoken around the globe, speech perception is arguably one of the main achievements of the human brain. While there is now broad support among cognitive neuroscientists for the concept of a hierarchy of cortical areas subserving auditory and speech processing, there is substantial disagreement about the roles different brain areas play in speech recognition, how the speech system learns and represents spoken words, and how learning words through one sense (e.g., through reading) can allow the brain to recognize the same words through another sense (e.g., through hearing). With support from the National Science Foundation, we will use advanced functional magnetic resonance imaging (fMRI) to investigate these questions. Specifically, the project is designed to resolve a major ongoing controversy regarding how and where words are represented in the brain by, for the first time, applying fMRI techniques to this field that have been used successfully to answer related questions in the domain of written words. A second study will probe how the brain learns new spoken words and adds them to the auditory lexicon. In the final set of studies, the project will break new ground in our understanding of how the auditory and visual systems are linked in reading, and how this interaction is enabled by cross-sensory learning. Understanding the neural bases of speech processing and cross-sensory learning of language are areas of great interest not only for basic science but also other areas ranging from education and language learning to engineering (by elucidating effective learning algorithms for deep multisensory hierarchies, e.g., for automatic speech recognition) as well as biomedical fields (by building a foundation to study a range of disorders, including dyslexia and language comprehension deficits). The research project will form an opportunity to train the next generation of scientists, at the graduate, undergraduate, and high school levels. In more scientific detail, the overarching goal of the proposed project is to study the existence and plasticity of auditory lexica in the human brain, and to understand coupling of written and auditory speech representations that permit cross-modal transfer of lexical learning. The project has three Aims: Aim 1 addresses the current controversy regarding the existence and location of auditory word representations in the brain. Translating techniques we previously developed to identify a "visual lexicon" in the "Visual Word Form Area", we will use sensitive fMRI rapid adaptation (fMRI-RA) and other advanced fMRI techniques to test the hypothesis of a (receptive) auditory lexicon within an analogous "Auditory Word Form Area" in left anterior superior temporal cortex. At the same time, we will test whether another lexicon exists in motor-related speech areas of the auditory dorsal stream representing articulatory word forms that are automatically activated by speech perception via an "inverse model". Aim 2 is designed to probe the plasticity invoked by the addition of novel words to the auditory lexicon. Aim 3 studies the interaction of written language with the auditory system. Prior studies have shown that reading activates phonological representations in proficient readers, and that this phonological recoding is crucial for reading acquisition. We will test the novel hypothesis that written words cause widespread activation of the auditory system and that training on novel written words can drive word-selective rewiring in the auditory lexical system.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.