大腦在夜晚也繼續工作？

熊子云

Why do we need sleep？ Is bedtime just a time for dreaming？ Do our brains turn off for the night？ What if I told you that scientists recently discovered that our brains may be just as busy at night as they are during the day？

為什么我們需要睡眠呢？睡覺的這段時間僅僅是為了做夢嗎？我們的大腦在夜間是否處于休息狀態呢？如果我告訴你，據最近的科學研究，我們的大腦在夜間也像白天一樣忙碌，你對此有何看法？

While we sleep， our brains are doing much more than getting ready for the next day. Researchers at the University of Rochester found that the brain may be busy cleaning house— cleaning out harmful waste materials.

當我們處于睡眠狀態時，大腦不僅僅只是為明天做準備。羅切斯特大學的研究人員發現，大腦在夜間也許正忙于清理房子——掃除有害的垃圾。

They studied mice that had colored dye injected1 into their brains. They observed the mice brains as they slept and when they were awake. The researchers say they saw that the brains of sleeping mice were hard at work.

研究人員將彩色染料注入老鼠的腦內并在它們睡眠和清醒時觀察他們的大腦。結果發現，老鼠的大腦在它們睡眠時也在忙碌地工作。

Working Double Duty

雙重任務

Dr. Maiken Nedergaard led the study. The brain expert says our brains perform two very different jobs. It seems they have daytime jobs. Later they “moonlight” at a nighttime job.

麥肯·尼達加特博士負責這項研究。腦專家認為我們的大腦執行著兩項十分不同的工作，不僅有日間的工作，之后還要“兼職”做一些夜間的工作。

“When we are awake， the brain cells2 are working very hard at processing all the information about our surroundings3. Whereas when we are asleep， they work very， very hard at removing4 all the waste that builds up when we are awake.”

當我們醒著時，大腦細胞拼命工作，處理關于我們四周環境的信息。但是，當我們睡覺時，它們也仍然拼命掃除我們醒著時在腦中積累的垃圾。

The researchers say that the waste material includes poisons， or toxins， responsible for brain disorders5 such as Alzheimers disease.

研究人員認為這些垃圾包括各種毒素。這些毒素是一些大腦疾病——如老年癡呆癥的誘因。

They also found that during sleep， the brains cells shrink， or become smaller. This shrinking permits waste to be removed more effectively.

研究人員也發現，大腦細胞在睡眠中會收縮或變小。這種收縮運動可以更有效的清理垃圾。

Dr. Nedergaard says these toxins end up in the liver. There， they are broken down and then removed from the body.

麥肯·尼達加特博士說這些毒素會轉移到肝臟。在肝臟中，這些毒素被分解，然后被排出。

“So our study suggests we need to sleep because we have a macroscopic cleaning system that removes many of the toxic waste products from the brain.”

“所以我們的研究證明了睡眠對于人們的重要性。因為我們有一個微觀的清理系統來清除大腦中的很多有害物質。”

The brains cleaning system could only be studied with new imaging technologies. The test animal must be alive in order to see for this brain process to be seen as it happens.

研究人員只能利用最新的成像技術來觀察大腦的清理系統。試驗中的動物必須是活的，以保證這一大腦運行過程能被觀察到。

Dr. Nedergaard says the next step is to look for the process in human brains. She said the results demonstrate6 just how important sleep is to health and fighting disease. The research may also one day lead to treatments to prevent or help fight neurological disorders.

尼達加特博士表示下一步的工作將是觀察人腦的運行過程。她指出目前的實驗結果僅僅證明了睡眠對于健康和預防疾病的重要性。這一研究將來也許有助于預防和治療神經性疾病。

7 Tips for Better Sleeping

7條保持良好睡眠的建議

Do you have trouble sleeping？ Not being able to sleep is called insomnia. According to the United States National Sleep Foundation， here are some tips for a good nights sleep：

你入睡困難嗎？我們用“失眠”來定義人們無法入睡的情況。為了保證一夜的睡眠，美國國家睡眠基金會提出了以下建議：

1. Go to bed about the same time each night， even on weekends. This helps to“set” your bodys “sleep clock.”

每晚在同一時間上床睡覺，即使是周末也要如此。這一方法有助于“設定”身體的“睡眠生物鐘。”

2. Exercise every day.

每天運動。

3. Have a calm， relaxing bedtime routine7—Take a warm bath or drink a hot cup of tea.

擁有一個平靜、放松的睡前習慣——洗個熱水澡或喝杯熱茶。

4. Try not to take long naps during the day. Periods of sleep during the daytime can interfere8 with sleep at night.

白天小睡時間不宜過長。白天的睡眠時長會影響夜晚的睡眠。

5. Make sure you have a pleasant environment where you sleep. For most people， a cool， quiet and dark room is best for sleeping.

確保你有一個舒適的睡眠環境。對于大多數人來說，一個涼爽、安靜和黑暗的房間最適合睡眠。

6. Avoid using television， computers and other electronic screens before bedtime.

睡前避免盯著電視，電腦和其它電子屏幕。

7. Also avoid alcohol， cigarettes and heavy meals before bedtime.

睡前避免喝酒、吸煙和飲食過量。

——英語原文摘自VOA Special

[1] inject vt. 注入；注射 [2] cell n. 細胞 [3] surrounding n. 環境，周圍的事物

[4] remove vt. 移動，遷移；調動 [5] disorder n. 混亂 [6] demonstrate vt. 證明；展示；論證

[7] routine n. 例行公事 [8] interfere vi. 干涉；妨礙；打擾