Background Mental fatigue is usually caused by long-term cognitive activities, mainly manifested as drowsiness, difficulty in concentrating, decreased alertness, disordered thinking, slow reaction, lethargy, reduced work efficiency, error-prone and so on. Mental fatigue has become a widespread sub-health condition, and has a serious impact on the cognitive function of the brain. However, seldom studies investigate the differences of mental fatigue on electrophysiological activity both in resting state and task state at the same time. Here, twenty healthy male participants were recruited to do a consecutive mental arithmetic tasks for mental fatigue induction, and electroencephalogram (EEG) data were collected before and after each tasks. The power and relative power of five EEG rhythms both in resting state and task state were analyzed statistically. Results The results of brain topographies and statistical analysis indicated that mental arithmetic task can successfully induce mental fatigue in the enrolled subjects. The relative power index was more sensitive than the power index in response to mental fatigue, and the relative power for assessing mental fatigue was better in resting state than in task state. Furthermore, we found that it is of great physiological significance to divide alpha frequency band into alpha1 band and alpha2 band in fatigue related studies, and at the same time improve the statistical differences of sub-bands. Conclusions Our current results suggested that the brain activity in mental fatigue state has great differences in resting state and task state, and it is imperative to select the appropriate state in EEG data acquisition and divide alpha band into alpha1 and alpha2 bands in mental fatigue related researches.

中文翻译：

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精神疲劳对大脑活动的影响：利用脑电图进行静息状态和任务状态的比较研究


背景精神疲劳通常是由长期认知活动引起的，主要表现为嗜睡、注意力不集中、警觉性下降、思维紊乱、反应迟钝、嗜睡、工作效率降低、容易出错等。精神疲劳已成为一种普遍存在的亚健康状态，严重影响大脑的认知功能。然而，很少有研究同时探讨精神疲劳对静息状态和任务状态下电生理活动的差异。在这里，招募了 20 名健康男性参与者，进行连续的心算任务以诱导精神疲劳，并在每个任务之前和之后收集脑电图 (EEG) 数据。对静息状态和任务状态下五种脑电节律的功率和相对功率进行统计分析。结果脑拓扑图和统计分析结果表明，心算任务能够成功诱导入组受试者的精神疲劳。相对功率指数对心理疲劳的反应比功率指数更敏感，并且相对功率指数在静息状态下比在任务状态下更能评估心理疲劳。此外，我们发现在疲劳相关研究中将α频段分为α1频段和α2频段，同时改善子频段的统计差异具有重要的生理意义。结论 我们目前的研究结果表明，精神疲劳状态下的大脑活动在静息状态和任务状态下存在较大差异，在精神疲劳相关研究中，选择合适的脑电数据采集状态并将α波段划分为α1和α2波段势在必行。 。