Lim Julian, Teng James, Wong Kian Foong, Chee Michael W L
Center for Cognitive Neuroscience, Duke-NUS Medical School, Singapore 169857, Singapore.
Center for Cognitive Neuroscience, Duke-NUS Medical School, Singapore 169857, Singapore.
Neuroimage. 2016 Jul 1;134:64-73. doi: 10.1016/j.neuroimage.2016.03.077. Epub 2016 Mar 31.
Rest breaks are commonly administered as a countermeasure to reduce on-the-job fatigue, both physical and mental. However, this practice makes the assumption that recovery from fatigue, as measured by the reversal of performance declines, is the sole effect of taking a break on behavior. Here, through administering rest breaks of differing lengths in between blocks of a mentally demanding symbol decoding task, we show that this assumption may not be strictly true. First, we replicate previous work by showing that taking a longer break leads to two correlated effects: greater immediate rebound in performance, and greater subsequent time-on-task decline. Using fMRI, we reveal that time-on-task in this paradigm is associated with increasing recruitment of fronto-parietal areas associated with top-down control, and decreasing deactivation in the default-mode network. Finally, by analyzing individual differences, we reveal a potential neural basis for our behavioral observation: greater recovery following long breaks is associated with greater activity in the putamen, an area associated with the automatic generation of motor responses, followed by greater activity in left middle frontal gyrus by the end of those task periods. Taken together, this suggests a shift in the implicit engagement of automatic and controlled attentional processing following longer breaks. This shift may be undesirable or detrimental in real-world situations where maintaining a stable level of attention over time is necessary.
休息时段通常作为一种对策来减轻工作中的身体和精神疲劳。然而，这种做法假定通过绩效下降的逆转来衡量的疲劳恢复是休息对行为的唯一影响。在此，通过在一项要求较高的符号解码任务的各块之间安排不同时长的休息时段，我们表明这一假设可能并不完全正确。首先，我们重复了之前的研究，结果表明休息时间更长会导致两种相关效应：绩效的即时反弹更大，以及随后任务执行时间的下降幅度更大。使用功能磁共振成像（fMRI），我们发现该范式下的任务执行时间与与自上而下控制相关的额顶叶区域的募集增加以及默认模式网络中的失活减少有关。最后，通过分析个体差异，我们揭示了我们行为观察的潜在神经基础：长时间休息后的更大恢复与壳核（与运动反应的自动生成相关的区域）中更大的活动有关，随后在那些任务阶段结束时左中额叶回有更大的活动。综合来看，这表明长时间休息后自动和受控注意力加工的隐性参与发生了转变。在需要长时间保持稳定注意力水平的现实世界情境中，这种转变可能是不利的或有害的。
