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.

    如果你相信當你睡覺的時候你的大腦也在休息，那么你錯了——它實際上在強化對白天發生的事情的記憶。

    美國研究者的一項研究顯示當你睡眠的時候，你的大腦仍然在忙碌的工作著。它在強化你對自己白天做過的事情的記憶，白天的經歷在腦中飛快地重放。

    “睡眠時大腦中部的額葉前部皮質會以實際速度的6到7倍快速重放白天發生的事情。”醫學博士韋伯在報告中引述這項研究的領導大衛博士的話如是說。實際上，亞利桑那州立大學的優斯頓博士和他的研究者同事們是通過監視嚙齒目動物大腦的活動得出這些結論的，這些嚙齒動物在白天學習了以某種特定的方式圍繞一個圓形競技場奔跑。
    
    研究團隊發現當老鼠們睡覺的時候，它們大腦中部的額葉前部皮質由和白天在競技場奔跑時一致的活動表現。

    但是睡眠的時候，那些大腦的圖像變化比它們醒著在競技場繞圈兒時要快6到7倍。

    “總之，在睡眠時老鼠的大腦活動加速了，以鞏固記憶。”優斯頓博士說道。最近一期的《科學》雜志上報道了他的這一發現。

    Vocabulary:

    prefrontal cortex：額葉前部皮質