Kim Yujin, Woo Jihwan, Woo Minjung
1 Department of Physical Education, Kyungpook National University, South Korea.
2 Department of Biomedical Engineering, 35029 University of Ulsan , South Korea.
Percept Mot Skills. 2017 Dec;124(6):1194-1210. doi: 10.1177/0031512517732851. Epub 2017 Sep 24.
This study investigated interactive effects of stress and task difficulty on working memory and cortico-cortical communication during memory encoding. Thirty-eight adolescent participants (mean age of 15.7 ± 1.5 years) completed easy and hard working memory tasks under low- and high-stress conditions. We analyzed the accuracy and reaction time (RT) of working memory performance and inter- and intrahemispheric electroencephalogram coherences during memory encoding. Working memory accuracy was higher, and RT shorter, in the easy versus the hard task. RT was shorter under the high-stress (TENS) versus low-stress (no-TENS) condition, while there was no difference in memory accuracy between the two stress conditions. For electroencephalogram coherence, we found higher interhemispheric coherence in all bands but only at frontal electrode sites in the easy versus the hard task. On the other hand, intrahemispheric coherence was higher in the left hemisphere in the easy (versus hard task) and higher in the right hemisphere (with one exception) in the hard (versus easy task). Inter- and intracoherences were higher in the low- versus high-stress condition. Significant interactions between task difficulty and stress condition were observed in coherences of the beta frequency band. The difference in coherence between low- and high-stress conditions was greater in the hard compared with the easy task, with lower coherence under the high-stress condition relative to the low-stress condition. Stress seemed to cause a decrease in cortical network communications between memory-relevant cortical areas as task difficulty increased.
本研究调查了压力和任务难度对记忆编码过程中工作记忆及皮质-皮质通信的交互作用。38名青少年参与者（平均年龄15.7±1.5岁）在低压力和高压力条件下完成了简单和困难的工作记忆任务。我们分析了记忆编码过程中工作记忆表现的准确性和反应时间（RT）以及半球间和半球内脑电图相干性。与困难任务相比，简单任务的工作记忆准确性更高，RT更短。高压力（经皮电刺激）条件下的RT比低压力（无经皮电刺激）条件下更短，而两种压力条件下的记忆准确性没有差异。对于脑电图相干性，我们发现在简单任务与困难任务中，除了额叶电极部位外，所有频段的半球间相干性在简单任务中更高。另一方面，半球内相干性在简单任务（与困难任务相比）中左半球更高，在困难任务（与简单任务相比）中右半球更高（有一个例外）。低压力条件下的半球间和半球内相干性高于高压力条件。在β频段的相干性中观察到任务难度和压力条件之间存在显著的交互作用。与简单任务相比，困难任务中低压力和高压力条件下相干性的差异更大，高压力条件下的相干性相对于低压力条件更低。随着任务难度的增加，压力似乎导致与记忆相关的皮质区域之间的皮质网络通信减少。
