The Neurophysiological Dynamics of Lexical and Sub-Lexical Representations

词汇和亚词汇表征的神经生理学动力学

• 批准号: 8751743
• 负责人: Matthew Kanter Leonard
• 金额: $ 5.6万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8751743
• 关键词: Access to Information; Acoustics; Aphasia; Area; Auditory; Autistic Disorder; Base of the Brain; Bilateral; Brain; Brain imaging; Characteristics; Chronic; Cochlear Implants; Code; Complex; Comprehension; Contralateral; Data; Diagnosis; Dimensions; Disease; Dyslexia; Electrocorticogram; Electrodes; Epilepsy; Feedback; Frequencies; Functional Magnetic Resonance Imaging; Hearing; Human; Image; Implant; Individual; Inferior; Injury; Intractable Epilepsy; Language; Language Development; Language Disorders; Lateral; Lead; Length; Linguistics; Magnetoencephalography; Methods; Modality; Participant; Patients; Pattern; Phonetics; Population; Population Control; Probability; Process; Property; Resolution; Sampling; Self-Help Devices; Semantics; Sensory; Series; Signal Transduction; Speech; Speech Disorders; Speech Perception; Speech Sound; Stimulus; Stream; Structure; Superior temporal gyrus; Surface; Techniques; Temporal Lobe; Time; Training; Translating; abstracting; cognitive function; density; developmental disease; encephalography; healthy volunteer; imaging modality; improved; indexing; language processing; lexical; lexical processing; meetings; millisecond; neurophysiology; prevent; public health relevance; relating to nervous system; response; sensory input; sound; spatiotemporal; specific language impairment; statistics

DESCRIPTION (provided by applicant): The broad objective of this proposal is to investigate how the brain constructs word-form and lexical representations of spoken words from lower-level acoustic-phonetic and phonemic information. The brain's ability to parse meaning from acoustic sensory inputs within a few hundred milliseconds may arise from multiple levels of representation that increase in abstraction as information is processed through local and long-distance cortical circuits in the classical language network. These processes will be studied using an integrated, multimodal neurophysiological approach that combines high-resolution invasive electrocorticography (ECoG) in epilepsy patients implanted with chronic subdural electrodes, and non-invasive magnetoencephalography (MEG), which provides whole-brain coverage of neural activity. The techniques are highly complementary and will provide unprecedented spatiotemporal resolution to characterize lexical processing as it unfolds on the millisecond level across adjacent neural populations. The primary analysis for ECoG and MEG data will involve constructing a neural "state-space", which represents the common activity across electrodes. Recently-developed methods allow the activity to be visualized in the state-space across time as neural trajectories. Participants will hear a list of words, each spoken by four different speakers, and the neural trajectories will be traced from the acoustic onset to the hypothesized lexical and semantic representations between 200-400ms later. It is hypothesized that different instances of the same word will begin in different parts of the state-space (due to acoustic differences across speakers), and will eventually converge into areas that represent neural activity associated with a particular lexical item. These analyses will be performed with data from ECoG in epilepsy patients, and will also be confirmed with healthy controls in MEG. MEG will provide additional information about these trajectories, since it is able to sample the entire cortex, and may detect relevant activity in areas that are not covered by the ECoG grids (for example, areas in the contralateral hemisphere). Finally, since the stimuli will be carefully controlled for linguistic features such as lexical frequency and phonotactic probability, it will b possible to examine how stimulus-level statistical properties are encoded by hypothesized prediction mechanisms in the brain. In general, these approaches will elucidate the processes of abstraction and higher-level representation for words in the brain, and will be among the first studies to characterize the neural code for speech perception from the perspective of dynamic, interactive processes. Understanding how the brain constructs word-level representations that contain a rich, malleable, and complex meaning is crucial for characterizing, diagnosing, and treating disorders that impair language learning and processing. It may also help improve assistive technologies like cochlear implants. The ability to decode neural representations at this level will further our understanding of fundamental brain processes that underlie many aspects of higher cognitive function.

描述（由申请人提供）：该提案的广泛目的是研究大脑如何构建来自低级声音和音素信息的口语单词的单词形式和词汇表示。大脑从几百毫秒内的声学感觉输入中解析含义的能力可能是由于多种级别的表示会引起，随着信息通过经典语言网络中的局部和长距离皮质回路处理，抽象的增加。这些过程将使用综合的多模式神经生理学方法研究，该方法结合了植入慢性硬膜下电极的癫痫患者中的高分辨率侵入性皮肤摄影（ECOG），并提供了非侵入性磁磁性磁通术（MEG）（MEG），可提供全脑活动的全脑活动。这些技术是高度互补的，将提供前所未有的时空分辨率，以表征词汇处理，因为它在相邻神经种群的毫秒内展开。 ECOG和MEG数据的主要分析将涉及构建神经“状态空间”，该神经“状态空间”代表跨电极的共同活性。最近开发的方法允许在整个时间的状态空间中以神经轨迹的形式可视化活动。参与者将听到一系列单词列表，每个说话者都会说出每个扬声器，而神经轨迹将从声学发作到200-400ms之间的假设的词汇和语义表示。假设相同单词的不同实例将从状态空间的不同部分开始（由于扬声器之间的声学​​差异），并最终会汇聚为代表与特定词汇项目相关的神经活动的区域。这些分析将使用来自ECOG的癫痫患者的数据进行，也将通过MEG中的健康对照进行确认。 MEG将提供有关这些轨迹的其他信息，因为它能够采样整个皮层，并且可以检测到ECOG网格未覆盖的区域的相关活动（例如，对侧半球区域）。最后，由于刺激将被仔细控制语言特征，例如词汇频率和音调概率，因此B可以检查刺激级别的统计特性如何通过大脑中假设的预测机制编码。通常，这些方法将阐明大脑单词的抽象过程和更高级别的表示的过程，并将成为最早从动态，互动过程的角度来表征语音感知的神经代码的研究之一。了解大脑如何构建包含丰富，可延展和复杂含义的单词级表示对于表征，诊断和治疗损害语言学习和处理的疾病至关重要。它还可能有助于改善诸如人工耳蜗植入物之类的辅助技术。在此解码神经表示的能力 水平将进一步理解基本的大脑过程，这些过程是较高认知功能的许多方面的基础。