If you believe that when you go to sleep your brain takes rest, you are wrong -- it actually strengthens the memories of events that took place during the day.

    Researchers in the United States have carried out a study and found while you sleep, your brain remains busy in strengthening the memories of what you did during the day and it does it in quick spurts, as if your day was being replayed in fast-forward.

    "The brain's medial prefrontal cortex replays daytime activities during sleep six to seven times faster than real time," the WebMD reported, quoting lead researcher Dr David Euston was quoted as saying.

    In fact, Dr Euston and his fellow researchers at the University of Arizona came to the conclusion after monitoring brain activity in rodents that had spent the day learning to scamper around a circular arena in a particular pattern.

    The team found that while the rats slept, their medial prefrontal cortex had spurts of activity that matched brain activity while the rodents had been running around the arena earlier in the day.

    They took that as a sign which the rats' brains were replaying the experience of learning the route around the arena. But during sleep, those brain patterns happened six to seven times faster than the time it had taken the rodents to scurry around the arena while awake.

    "In short, the rats' brain activity kicked into overdrive during sleep to consolidate memories," Dr Euston, who reported the findings in the latest edition of Science journal, was quoted as saying.

    如果你相信当你睡觉的时候你的大脑也在休息，那么你错了——它实际上在强化对白天发生的事情的记忆。

    美国研究者的一项研究显示当你睡眠的时候，你的大脑仍然在忙碌的工作着。它在强化你对自己白天做过的事情的记忆，白天的经历在脑中飞快地重放。

    “睡眠时大脑中部的额叶前部皮质会以实际速度的6到7倍快速重放白天发生的事情。”医学博士韦伯在报告中引述这项研究的领导大卫博士的话如是说。实际上，亚利桑那州立大学的优斯顿博士和他的研究者同事们是通过监视啮齿目动物大脑的活动得出这些结论的，这些啮齿动物在白天学习了以某种特定的方式围绕一个圆形竞技场奔跑。
    
    研究团队发现当老鼠们睡觉的时候，它们大脑中部的额叶前部皮质由和白天在竞技场奔跑时一致的活动表现。

    但是睡眠的时候，那些大脑的图像变化比它们醒着在竞技场绕圈儿时要快6到7倍。

    “总之，在睡眠时老鼠的大脑活动加速了，以巩固记忆。”优斯顿博士说道。最近一期的《科学》杂志上报道了他的这一发现。

    Vocabulary:

    prefrontal cortex：额叶前部皮质