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，缺乏睡眠的人會經(jīng)歷大腦功能接近正常水平的時期，但這些時期會被注意力嚴(yán)重下降所打斷，這類似于停電。

刊載于《神經(jīng)科學(xué)雜志》(Journal of Neuroscience)的這篇研究，突出表明從事重要工作的人防范睡眠缺乏的重要性，例如夜間駕駛。

來自新加坡研究生醫(yī)學(xué)院杜克—國立大學(xué)(Duke-National University of Singapore Graduate Medical School)的研究小組，利用功能性磁共振成像技術(shù)，對整夜不睡或夜間睡眠很好的人的大腦血液流量進(jìn)行了測試。

在成像過程中，研究人員向參與者展示了由許多較小字母組成的大字母。然后，要求參與者識別大的或小的字母，并通過按按鈕來顯示他們的反應(yīng)。

不管是在缺乏睡眠還是得到良好休息的狀態(tài)下，那些反應(yīng)最為迅速的參與者都顯示出了相似的大腦活動模式。

然而，那些得到很好休息和缺乏睡眠的反應(yīng)最慢（也被稱為注意力缺失）的參與者，顯示出各種各樣的大腦活動模式。

研究人員發(fā)現(xiàn)，在注意力缺失期間，與休息良好的志愿者相比，缺乏睡眠的志愿者大腦指令中心的活動減少。這項發(fā)現(xiàn)表明，缺乏睡眠會降低大腦補償注意力缺失的能力。

缺乏睡眠的人還顯示出，在注意力缺失期間，包括視覺處理在內(nèi)的大腦區(qū)域的活動也會降低。

由于在睡眠過程中，大腦對感官刺激的反應(yīng)會下降，這些區(qū)域大腦活動的降低表明，在注意力缺失期間，缺乏睡眠的大腦進(jìn)入了一種類似于睡眠的狀態(tài)。