Imaging research shows people who are sleep-deprived experience periods of near-normal brain function, but these periods are interspersed with severe drops in attention, akin to power failure.

The study, published in the Journal of Neuroscience, highlights the importance of preventing sleep deprivation in people doing critical tasks, such as night driving.

The research team, from the Duke-National University of Singapore Graduate Medical School, used functional magnetic resonance imaging to measure brain blood flow in people who were either kept awake all night or allowed a good night's sleep.

During imaging, researchers showed participants large letters made up of many smaller letters. Participants were then asked to identify either the large or small letters and to indicate their responses by pushing a button.

Those participants with the fastest responses, both in sleep-deprived and well-rested conditions, showed similar patterns of brain activity.

However, those well-rested and sleep-deprived participants with the slowest responses – also known as attentional lapses – showed varying patterns of brain activity.

During attentional lapses, researchers discovered diminished activity in the brain command centres in sleep-deprived compared to well-rested volunteers. This finding suggests that sleep deprivation reduces the brain's ability to compensate for lost focus.

Sleep-deprived people also showed reduced activity in brain regions involved in visual processing during attention lapses.

Because the brain becomes less responsive to sensory stimuli during sleep, reduced activity in these regions indicates that, during attention lapses, the sleep-deprived brain enters a sleep-like state.

成像研究表明，缺乏睡眠的人会经历大脑功能接近正常水平的时期，但这些时期会被注意力严重下降所打断，这类似于停电。

刊载于《神经科学杂志》(Journal of Neuroscience)的这篇研究，突出表明从事重要工作的人防范睡眠缺乏的重要性，例如夜间驾驶。

来自新加坡研究生医学院杜克—国立大学(Duke-National University of Singapore Graduate Medical School)的研究小组，利用功能性磁共振成像技术，对整夜不睡或夜间睡眠很好的人的大脑血液流量进行了测试。

在成像过程中，研究人员向参与者展示了由许多较小字母组成的大字母。然后，要求参与者识别大的或小的字母，并通过按按钮来显示他们的反应。

不管是在缺乏睡眠还是得到良好休息的状态下，那些反应最为迅速的参与者都显示出了相似的大脑活动模式。

然而，那些得到很好休息和缺乏睡眠的反应最慢（也被称为注意力缺失）的参与者，显示出各种各样的大脑活动模式。

研究人员发现，在注意力缺失期间，与休息良好的志愿者相比，缺乏睡眠的志愿者大脑指令中心的活动减少。这项发现表明，缺乏睡眠会降低大脑补偿注意力缺失的能力。

缺乏睡眠的人还显示出，在注意力缺失期间，包括视觉处理在内的大脑区域的活动也会降低。

由于在睡眠过程中，大脑对感官刺激的反应会下降，这些区域大脑活动的降低表明，在注意力缺失期间，缺乏睡眠的大脑进入了一种类似于睡眠的状态。