Brain oscillatory dynamics in lexical-semantic processing

当大脑理解一个词的意义时，它会经历两种类型的词汇语义处理：自动的和受控的。自动化过程不受意识控制，而受控过程可以。这些类型的加工过程所涉及的语言网络的不同之处在于，自动加工过程主要在左颞叶中招募区域，而控制加工过程则在左颞叶和左前额叶皮层中招募区域。但是，描述参与某些过程的解剖区域只能让我们对支持这些过程的静态网络有一种感觉。我们建议研究如何通过大脑振荡的同步机制来创建词汇语义处理的动态网络。已经提出，脑振荡的同步能够动态地招募本地神经群体并连接遥远的群体进行通信。振荡的同步可以使用EEG并分析数据的时间、频率、相位和幅度来测量。我们建议使用这些方法在新的应用研究自动和控制词汇语义处理。本项目的目的是研究自动和受控（特别是受控的单一意义选择）词汇语义过程中左颞叶和前额叶皮层的局部同步和左额颞叶网络的长距离同步;在这项奋进中，我们将利用两种语义语境范式。我们还将研究如何动态形成的词汇语义网络可能会中断失语症作为一个可能的洞察他们的语言理解障碍。

When the brain accesses the meaning of a word, it undergoes two types of lexical-semantic processing: automatic and controlled. Automatic processes are not under conscious control, while controlled processes can be. The language networks involved in these types of processes differ in that automatic processes mostly recruit areas in the left temporal lobe while controlled processes recruit areas in both the left temporal lobe and the left prefrontal cortex. But describing the anatomical areas involved in certain processes can only give us a sense of the static network that supports these processes. We propose to investigate how a dynamic network for lexical-semantic processing may be created through the mechanism of synchronization of brain oscillations. It has been proposed that synchronization of brain oscillations is able to dynamically recruit local neural populations and connect far away populations for communication. Synchronization of oscillations can be measured using EEG and analyzing the time, frequency, phase, and amplitude of the data. We propose to use these methods in the novel application of studying automatic and controlled lexical-semantic processing. The aims of this project are to study local synchronization in the left temporal and prefrontal cortices and long- distance synchronization over the left fronto-temporal network in automatic and controlled (specifically controlled single meaning selection) lexical-semantic processes; in this endeavor, we will utilize two semantic context paradigms. We will also examine how the dynamic formation of the lexical-semantic network may be disrupted in aphasics as a possible insight into their language comprehension impairments.