持续关注,作为一般认知能力的基础,自然在不同的时间尺度上有所不同,从几个小时开始,例如,从清醒到困倦状态,到秒,例如,任务会话中的逐条试验波动。在这种跨尺度变异性之下是否存在统一的机制尚不清楚。在这里,我们表明,皮质兴奋/抑制(E/I)的波动是人类跨时间尺度持续注意力的强大调节剂。首先,我们观察到不同大脑状态下的注意力能力不同(觉醒,餐后嗜睡,睡眠不足),以及在任何具有较大波动的单个状态中。第二,不管涉及的时间尺度,我们发现高度专注的状态总是与以脑电图(EEG)特征为特征的更平衡的皮质E/I有关,虽然偏离平衡状态会导致注意力暂时下降,提示皮质E/I的波动是跨尺度注意变异性下的常见机制。此外,我们发现持续注意力和皮质E/I指数的变化在时域中表现出分形结构,具有自相似性的特征。一起来看,这些结果表明,持续的注意力在不同的时间尺度上自然会以比以前理解的更复杂的方式变化,皮质E/I作为共享的神经生理调节剂。
Sustained attention, as the basis of general cognitive ability, naturally varies across different time scales, spanning from hours, e.g. from wakefulness to drowsiness state, to seconds, e.g. trial-by-trail fluctuation in a task session. Whether there is a unified mechanism underneath such trans-scale variability remains unclear. Here we show that fluctuation of cortical excitation/inhibition (E/I) is a strong modulator to sustained attention in humans across time scales. First, we observed the ability to attend varied across different brain states (wakefulness, postprandial somnolence, sleep deprived), as well as within any single state with larger swings. Second, regardless of the time scale involved, we found highly attentive state was always linked to more balanced cortical E/I characterized by electroencephalography (EEG) features, while deviations from the balanced state led to temporal decline in attention, suggesting the fluctuation of cortical E/I as a common mechanism underneath trans-scale attentional variability. Furthermore, we found the variations of both sustained attention and cortical E/I indices exhibited fractal structure in the temporal domain, exhibiting features of self-similarity. Taken together, these results demonstrate that sustained attention naturally varies across different time scales in a more complex way than previously appreciated, with the cortical E/I as a shared neurophysiological modulator.