School of Human Kinetics, University of Ottawa, 125 University Private, Ottawa, ON, Canada.
Exp Brain Res. 2022 Nov;240(11):3033-3047. doi: 10.1007/s00221-022-06444-1. Epub 2022 Oct 13.
Cognitive fatigue (CF) can result from sustained mental effort, is characterized by subjective feelings of exhaustion and cognitive performance deficits, and is associated with slowed simple reaction time (RT). This study determined whether declines in motor preparation underlie this RT effect. Motor preparation level was indexed using simple RT and the StartReact effect, wherein a prepared movement is involuntarily triggered at short latency by a startling acoustic stimulus (SAS). It was predicted that if decreased motor preparation underlies CF-associated RT increases, then an attenuated StartReact effect would be observed following cognitive task completion. Subjective fatigue assessment and a simple RT task were performed before and after a cognitively fatiguing task or non-fatiguing control intervention. On 25% of RT trials, a SAS replaced the go-signal to assess the StartReact effect. CF inducement was verified by significant declines in cognitive performance (p = 0.003), along with increases in subjective CF (p < 0.001) and control RT (p = 0.018) following the cognitive fatigue intervention, but not the control intervention. No significant pre-to-post-test changes in SAS RT were observed, indicating that RT increases resulting from CF are not substantially associated with declines in motor preparation, and instead may be attributable to other stages of processing during a simple RT task.
认知疲劳（CF）可由持续的脑力劳动引起，其特征是主观疲劳感和认知表现缺陷，并与反应时（RT）减慢有关。本研究旨在确定运动准备的下降是否是这种 RT 效应的基础。运动准备水平通过简单 RT 和 StartReact 效应来衡量，其中准备好的运动在短潜伏期内会被突发的声音刺激（SAS）无意识地触发。如果 CF 相关的 RT 增加是由于运动准备下降引起的，那么在认知任务完成后，应该会观察到减弱的 StartReact 效应。在认知疲劳任务或非疲劳对照干预前后，进行主观疲劳评估和简单 RT 任务。在 25%的 RT 试验中，SAS 取代了 go 信号，以评估 StartReact 效应。认知疲劳干预后，认知表现显著下降（p=0.003），同时主观 CF（p<0.001）和对照 RT（p=0.018）增加，这验证了 CF 的诱导作用，但对照干预后则没有。没有观察到 SAS RT 在测试前后有显著变化，这表明 CF 引起的 RT 增加与运动准备的下降没有明显关联，而是可能归因于简单 RT 任务中的其他处理阶段。
