Abstract：
Increasing time spent on the task (i.e., the time-on-task (ToT) effect) often results in mental fatigue. Typical effects of ToT are decreasing levels of task-related motivation and the deterioration of cognitive performance. However, a massive body of research indicates that the detrimental effects can be reversed by extrinsic motivators, for example, providing rewards to fatigued participants. Although several attempts have been made to identify brain areas involved in mental fatigue and related reward processing, the neural correlates are still less understood. In this study, we used the psychomotor vigilance task to induce mental fatigue and blood oxygen-level-dependent functional magnetic resonance imaging to investigate the neural correlates of the ToT effect and the reward effect (i.e., providing extra monetary reward after fatigue induction) in a healthy young sample. Our results were interpreted in a recently proposed neurocognitive framework. The activation of the right middle frontal gyrus, right insula and right anterior cingulate gyrus decreased as fatigue emerged and the cognitive performance dropped. However, after providing an extra reward, the cognitive performance, as well as activation of these areas, increased. Moreover, the activation levels of all of the mentioned areas were negatively associated with reaction times. Our results confirm that the middle frontal gyrus, insula and anterior cingulate cortex play crucial roles in cost-benefit evaluations, a potential background mechanism underlying fatigue, as suggested by the neurocognitive framework.
摘要：
增加在任务上花费的时间(即，任务时间（ToT）效应）通常会导致精神疲劳。ToT的典型影响是与任务相关的动机水平降低和认知表现恶化。然而,大量的研究表明，有害的影响可以被外在的动机逆转，例如,为疲劳的参与者提供奖励。尽管已经进行了一些尝试来识别与精神疲劳和相关奖励处理有关的大脑区域，神经相关性仍然知之甚少。在这项研究中,我们使用精神运动警觉任务来诱发精神疲劳和血氧水平依赖性功能磁共振成像，以研究ToT效应和奖励效应的神经相关性（即，在疲劳诱导后提供额外的金钱奖励)在健康的年轻样本中。我们的结果在最近提出的神经认知框架中得到了解释。右额中回的激活,右岛和右前扣带回随着疲劳的出现而减少，认知能力下降。然而,在提供额外奖励后，认知表现，以及激活这些区域，增加。此外，所有上述区域的激活水平与反应时间呈负相关。我们的结果证实了中额回，脑岛和前扣带皮质在成本效益评估中起着至关重要的作用，潜在的疲劳背景机制，正如神经认知框架所建议的那样。
