Facultad de Psicología, Universidad de Murcia, Campus de Espinardo, 30100, Murcia, Spain.
Sci Rep. 2022 Jan 11;12(1):547. doi: 10.1038/s41598-021-04607-8.
Current theoretical accounts on the oscillatory nature of sustained attention predict that entrainment via transcranial alternating current stimulation (tACS) at alpha and theta frequencies on specific areas of the prefrontal cortex could prevent the drops in vigilance across time-on-task. Nonetheless, most previous studies have neglected both the fact that vigilance comprises two dissociable components (i.e., arousal and executive vigilance) and the potential role of differences in arousal levels. We examined the effects of theta- and alpha-tACS over the right dorsolateral prefrontal cortex in both components of vigilance and in participants who differed in arousal level according to their chronotype and time of testing. Intermediate-types performed the vigilance tasks when their arousal level was optimal, whereas evening-types performed the vigilance tasks when their arousal levels were non-optimal. Both theta- and alpha-tACS improved arousal vigilance in the psychomotor vigilance task (PVT), whereas alpha-tACS, but not theta-tACS, improved executive vigilance in the sustained attention to response task (SART), and counteracted the typical vigilance decrement usually observed in this task. Importantly, these stimulation effects were only found when arousal was low (i.e., with evening-types performing the tasks at their non-optimal time of day). The results support the multicomponent view of vigilance, the relevance of heeding individual differences in arousal, and the role of alpha oscillations as a long-range cortical scale synchronization mechanism that compensates the decrements in performance as a function of time-on-task by exerting and maintaining cognitive control attributed to activation of the right dorsolateral prefrontal cortex.
目前关于持续注意力的波动性质的理论解释预测，经颅交流电刺激（tACS）在额前皮质特定区域的阿尔法和 theta 频率的同步作用，可以防止警觉度随着任务时间的推移而下降。然而，大多数先前的研究都忽略了一个事实，即警觉度包括两个可分离的成分（即觉醒和执行警觉），以及觉醒水平差异的潜在作用。我们研究了 theta 和 alpha-tACS 对右背外侧前额叶皮质在警觉度的两个成分中的作用，以及根据他们的昼夜类型和测试时间在觉醒水平上存在差异的参与者。中间型在他们的觉醒水平最佳时执行警觉任务，而晚上型在他们的觉醒水平不佳时执行警觉任务。theta 和 alpha-tACS 都改善了精神运动警觉任务（PVT）中的觉醒警觉，而 alpha-tACS 但不是 theta-tACS 改善了持续注意力反应任务（SART）中的执行警觉，并抵消了在这项任务中通常观察到的典型警觉度下降。重要的是，只有当觉醒度较低时（即晚上型在他们一天中不最佳的时间执行任务时）才会出现这些刺激效应。这些结果支持了警觉的多成分观点，以及注意个体觉醒差异的重要性，以及 alpha 振荡作为一种长程皮质尺度同步机制的作用，该机制通过发挥和维持归因于右背外侧前额叶皮质激活的认知控制来补偿随着任务时间的推移而导致的表现下降。
