Brain oscillatory dynamics in lexical-semantic processing

当大脑获取一个单词的意思时，它会经历两种类型的词汇语义处理：自动和控制。自动过程不受意识控制，而受控过程则可以。涉及这两种过程的语言网络的不同之处在于，自动过程主要使用左颞叶的区域，而受控过程同时使用左颞叶和左前额叶皮层的区域。但是描述与某些过程有关的解剖区域只能给我们一种支持这些过程的静态网络的感觉。我们建议研究如何通过大脑振荡的同步机制创建词汇语义加工的动态网络。有人提出，脑振荡的同步能够动态地招募局部神经群，并连接远处的神经群进行交流。振荡的同步可以测量使用脑电图和分析时间，频率，相位，和幅度的数据。我们建议将这些方法应用于自动和受控词汇语义加工的研究中。本研究的目的是研究自动和控制（特别是控制单一意义选择）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远距离同步；在这项工作中，我们将使用两种语义上下文范式。我们还将研究词汇-语义网络的动态形成如何在失语症中被破坏，以了解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.