Liu Xinyang, Liu Juntao, Duan Feng, Liu Rui, Gai Shuping, Xu Shengwei, Sun Jianhui, Cai Xinxia
State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100190, China.
State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
Neurosci Lett. 2017 Jul 13;653:326-331. doi: 10.1016/j.neulet.2017.06.008. Epub 2017 Jun 9.
Mental fatigue is often associated with continuous brain activities in our daily life. It can diminish efficiency and increase errors. However, the related physiological features are still not clear and under exploration. The present study investigated changes of inter-hemispheric synchronization in event-related potentials (ERPs) due to mental fatigue during sustained memory processing. Twenty-six participants performed a continuous two-back memory task for around 2.5h. Prefrontal and frontal synchronies in the alpha frequency band (8-13Hz) were analyzed because of their close relationships with memory functions. Coherence was used to examine bilateral synchronization changes of ERP power and phase. We compared ERP coherences in both non-fatigued and fatigued states. We also observed the variation of ERP coherences during the continuous task. High overlaps of inter-hemispheric ERP waveforms were observed at prefrontal and frontal cortex in both non-fatigued and fatigued conditions. During the whole experimental procedure, ERP alpha coherences at frontal regions (FP1-FP2 and F3-F4) were significantly higher than at central (C3-C4), parietal (P3-P4) and occipital (O1-O2) regions. Alpha synchronization in anterior electrode pairs showed significant declines with increasing mental fatigue during the memory task. Our findings about changes in frontal ERP alpha synchronization might be used as biomarkers to assess mental fatigue induced by prolonged memory demands.
精神疲劳在我们日常生活中常与持续的大脑活动相关。它会降低效率并增加错误。然而，相关的生理特征仍不明确，尚在探索之中。本研究调查了在持续记忆处理过程中，由于精神疲劳导致的事件相关电位（ERP）半球间同步性的变化。26名参与者进行了约2.5小时的连续双任务记忆测试。由于前额叶和额叶的α频段（8 - 13Hz）与记忆功能密切相关，因此对其同步性进行了分析。采用相干性来检测ERP功率和相位的双侧同步变化。我们比较了非疲劳状态和疲劳状态下的ERP相干性。我们还观察了连续任务过程中ERP相干性的变化。在非疲劳和疲劳状态下，在前额叶和额叶皮层均观察到半球间ERP波形的高度重叠。在整个实验过程中，额叶区域（FP1 - FP2和F3 - F4）的ERPα相干性显著高于中央（C3 - C4）、顶叶（P3 - P4）和枕叶（O1 - O2）区域。在记忆任务中，随着精神疲劳程度的增加，前部电极对之间的α同步性显著下降。我们关于额叶ERPα同步性变化的研究结果可能用作生物标志物，以评估由长期记忆需求引起的精神疲劳。
