Mental fatigue is the subjective state of people after excessive consumption of information resources. Its impact on cognitive activities is mainly manifested as decreased alertness, poor memory and inattention, which is highly related to the performance after impaired working memory. In this paper, the partial directional coherence method was used to calculate the coherence coefficient of scalp electroencephalogram (EEG) of each electrode. The analysis of brain network and its attribute parameters was used to explore the changes of information resource allocation of working memory under mental fatigue. Mental fatigue was quickly induced by the experimental paradigm of adaptive N-back working memory. Twenty-five healthy college students were randomly recruited as subjects, including 14 males and 11 females, aged from 20 to 27 years old, all right-handed. The behavioral data and resting scalp EEG data were collected simultaneously. The results showed that the main information transmission pathway of the brain changed under mental fatigue, mainly in the frontal lobe and parietal lobe. The significant changes in brain network parameters indicated that the information transmission path of the brain decreased and the efficiency of information transmission decreased significantly. In the causal flow of each electrode and the information flow of each brain region, the inflow of information resources in the frontal lobe decreased under mental fatigue. Although the parietal lobe region and occipital lobe region became the main functional connection areas in the fatigue state, the inflow of information resources in these two regions was still reduced as a whole. These results indicated that mental fatigue affected the information resources allocation of working memory, especially in the frontal and parietal regions which were closely related to working memory.
精神疲劳是人们信息资源过度消耗后的主观状态，其对认知活动的影响主要表现为警觉性降低、记忆力变差和注意力不集中，与工作记忆受损后的表现高度相关。本文采用部分定向相干法计算各电极头皮脑电信号的相干性系数，利用对脑网络及其属性参数的分析，探索精神疲劳状态下工作记忆信息资源分配的变化情况。实验采用自适应 N-back 工作记忆的实验范式快速诱发精神疲劳，随机招募 25 名身体健康的在校大学生作为被试，其中男性 14 名，女性 11 名，年龄在 20～27 岁，均为右利手，同步采集被试的行为学数据和静息态头皮脑电数据。结果显示，疲劳状态下大脑主要信息传输路径发生变化，主要表现在额叶区域和顶叶区域；脑网络参数的显著变化说明大脑的信息传输路径减少，信息传输效率显著下降；各电极因果流和各脑区间信息流中，疲劳状态下额叶区域信息资源流入减少，顶叶区域和枕叶区域虽然在疲劳状态下成为主要功能连接区域，但从整体来看这两个区域信息资源流入仍然是减少的。这些结果说明精神疲劳影响了工作记忆功能的信息资源分配，尤其是与工作记忆功能联系紧密的额叶区域和顶叶区域。.
Keywords: brain network; information resources; mental fatigue; working memory.