一种与N-Back诱发脑力疲劳相关的特异性脑电网络结构

A Specific EEG Network Structure Related to Mental Fatigue Induced by N-back

探究脑力疲劳引起的静息态脑电网络结构的改变,以及体力疲劳的引入对脑力疲劳相关脑电网络的影响。分别以2-back实验和功率自行车诱发脑力、体力疲劳,采集10名被试脑力疲劳前后以及体脑疲劳前后4种状态下20个导联的静息脑电信号(EEG),进行偏定向相干因果性分析。对被试的脑电网络连接逐个进行威尔科克森符号秩检验,选择PDC值显著性大于阈值的连接赋为1,构建出二值化脑电网络。通过对疲劳前后脑电网络的比较与拆分计算,提取出一个N-back实验下与脑力疲劳相关的特异性脑电网络结构,该网络以额区的FP2导联为中枢节点,呈现出由全脑所有导联指向FP2的规律。在脑力疲劳和体脑疲劳两种疲劳状态下,该网络的连接形式基本保持一致,连接系数分别是4.060 3和4.142 1,没有发生显著改变,所以是一种相对独立、稳定并与脑力疲劳密切相关的功能网络。该方法和结果有望为研究脑力疲劳和探索体脑疲劳交互影响机制提供一个新的视角。

The aim of this study was to investigate the changes of resting state EEG network structure caused by mental fatigue, and the influence of physical fatigue on the mental fatigue-related EEG network. Two-back task and cycling were used to induce mental fatigue and physical fatigue, respectively. Twenty channels of resting state EEG of 10 subjects were collected under 4 different fatigue conditions. EEG networks were obtained by calculating the partial directed coherence （PDC） causality between two arbitrary nodes and refined by comparing to a threshold. Only those links significantly higher than the threshold would be reserved, while others dismissed. After a comparison among the four EEG networks, a mental fatigue-related specific EEG network structure in N-back experiments was identified, in which FP2 was the hub while almost other channels had a link with it. The network structure was very stable, and its corresponding linking strength 4. 0603 and 4. 1421 in two fatigue state, which would not be influenced by physical fatigue. Therefore, this study identified an independent and stable functional network related to mental fatigue. The result provided a new perspective on the neural mechanism of mental fatigue and the relationship between mental fatigue and physical fatigue.