Electrocorticographic Analysis of Phonological and Lexical Processing

描述(由申请人提供)：语言感知和产生背后的皮质活动的时空动力学没有被很好地描绘出来。目前的神经成像技术如fMRI和PET提供了高的空间分辨率，但缺乏足够的时间分辨率来处理语言的时间动态。相比之下，EEG和MEG等电生理学技术提供了高时间分辨率，但缺乏确定哪些皮质网络对语音感知和产生起关键作用所需的空间分辨率。这一建议旨在通过分析在语言处理任务中获得的具有高时间分辨率和良好空间分辨率的电信号来弥补文献中的这一差距。这些实验包括直接从接受难治性癫痫治疗的患者的大脑皮层记录皮质脑电活动(ECoG)。在神经外科手术中，多个电极网被放置在大脑表面，提供了对左侧大脑皮质的广泛覆盖。高保真的ECoG信号包含丰富的信息频谱。除了经典的事件相关电位(ERP)分析外，时频分析技术还提供了一个了解本地和全球网络连接的窗口。我们将使用最近描述的高伽马振荡反应(HG：60-200赫兹)以及其他频段和事件相关电位作为神经活动的皮质标志物。我们将采用两项任务来阐明基本语音和词汇加工的时空动态。其中一项任务将包括听听音，然后重现它们，而另一项任务将使用相同实验结构中的单词。比较这两项任务将为确定参与语音和词汇加工的大脑皮层区域的时序动态奠定基础。此外，我们将研究额叶下回(IFG)在接受性加工中的作用。具体地说，我们将解决IFG在语音加工中的有争议的角色。除了提供与语言学理论相关的数据外，确定语言处理的空间和时间动态可能会导致公共卫生的进步。新的脑定位技术可能会在神经外科手术中为几种疾病(如癫痫、肿瘤切除)提供更短、更安全的程序，以其与癫痫诱导和标测过程的长度相关的发病率取代传统的皮质刺激标测。 与公共健康相关：这项提议将有助于创建一张大脑皮层地图，显示在理解和产生语言的过程中，不同的大脑区域何时何地活跃。这将扩展目前关于大脑如何处理语言的理论，并提供新的大脑成像技术。这种标测技术可以在神经外科手术中为几种疾病(如癫痫、肿瘤切除)提供更短、更安全的程序，以与癫痫诱导和标测程序的长度相关的发病率取代传统的皮质刺激标测。

DESCRIPTION (provided by applicant): The spatiotemporal dynamics of cortical activity underlying speech perception and production are not well delineated. Current neuroimaging techniques such as fMRI and PET provide high spatial resolution but lack sufficient temporal resolution to address the temporal dynamics of language. In contrast, electrophysiological techniques such as EEG and MEG offer high temporal resolution but lack the spatial resolution needed to ascertain what cortical networks are critically involved in speech perception and production. This proposal aims to address this gap in the literature by analyzing electrical signals with both high temporal resolution and excellent spatial resolution acquired during language processing tasks. The experiments involve recording electrocorticogrpahic activity (ECoG) directly from the cortex of patients undergoing treatment for refractory epilepsy. Multiple electrode grids are neurosurgically placed on the surface of the brain providing extensive coverage of left perisylvian language cortices. The high fidelity ECoG signal contains a rich spectrum of information. In addition to classical event related potential (ERP) analysis, time- frequency analysis techniques offer a window into local and global network connectivity. We will use the recently described high gamma oscillatory response (HG: 60-200 Hz) together with other frequency bands and ERPs as cortical markers for neural activity. We will employ two tasks aimed at elucidating the spatiotemporal dynamics of basic phonological and lexical processing. One task will consist of hearing auditorily-presented phonemes and then re-producing them while the other will use words in the same experimental structure. Comparing the two tasks will serve as a basis for ascertaining the timing dynamics of cortical regions involved in phonological and lexical processing. Furthermore, we will examine the role of the inferior frontal gyrus (IFG) in receptive processing. Specifically, we will address the controversial role of IFG in phonological processing. In addition to providing data relevant to linguistic theory, determining the spatial and temporal dynamics of language processing may lead to advances in public health. New brain mapping techniques may permit shorter and safer procedures during neurosurgery for several disorders (i.e. epilepsy, tumor resection) replacing the traditional cortical stimulation mapping with its associated morbidity related to seizure induction and length of the mapping procedure. PUBLIC HEALTH RELEVANCE: This proposal will help create a cortical map of where and when different brain regions are active during comprehension and production of language. This will expand current theories of how the brain processes language as well provides new brain mapping techniques. Such mapping techniques may permit shorter and safer procedures during neurosurgery for several disorders (i.e. epilepsy, tumor resection) replacing the traditional cortical stimulation mapping with its associated morbidity related to seizure induction and length of the mapping procedure.