新研究：如果睡眠不足，大腦就會開始吃自己

The need for sleep goes far beyond simply replenishing our energy levels every 12 hours. Our brains actually change states when we sleep to clear away the toxic byproducts of neural activity left behind during the day.

人們對睡眠的需求不僅僅是爲了每12個小時補充一下體力。實際上，我們睡覺的時候，大腦會改變狀態，清除白天神經活動留下的有毒副產物。

Weirdly enough, the same process starts to occur in brains that are chronically sleep-deprived too - except it's kicked into hyperdrive.

奇怪的是，長期睡眠不足，大腦內也會進行這樣的程序，只是它會進入過度清除狀態。

Researchers have found that persistently poor sleep causes the brain to clear a significant amount of neurons and synaptic connections, and recovering sleep might not be able to reverse the damage.

研究人員發現，長期睡眠不足會使大腦清除大量神經元和突觸連接，而且恢復睡眠也許並不能徹底修復損傷。

A team led by neuroscientist Michele Bellesi from the Marche Polytechnic University in Italy examined the mammalian brain's response to poor sleeping habits, and found a bizarre similarity between the well-rested and sleepless mice.

意大利馬爾理工大學神經科學家米歇爾·貝蕾西帶領的團隊研究了哺乳動物的大腦對睡眠不足的反應，他們發現休息時間充足的小鼠與睡眠不足的小鼠之間有古怪的相似性。

Like the cells elsewhere in your body, the neurons in your brain are being constantly refreshed by two different types of glial cell - support cells that are often called the glue of the nervous system.

就像你身體其他部位的細胞一樣，你大腦裏的神經元也在不斷被兩種不同的神經膠質細胞所更新，這些支持細胞經常被稱爲神經系統的粘合劑。

The microglial cells are responsible for clearing out old and worn out cells via a process called phagocytosis - meaning "to devour" in Greek.

這種微神經膠質細胞通過一個被稱爲吞噬現象（phagocytosis在希臘語中是“吞噬”的意思）的過程來清除老細胞和衰竭的細胞。

The astrocytes' job is to prune unnecessary synapses (connections) in the brain to refresh and reshape its wiring.

星型膠質細胞的作用是清除大腦中不必要的突觸（連接）來恢復並重塑它的神經網絡。

We've known that this process occurs when we sleep to clear away the neurological wear and tear of the day, but now it appears that the same thing happens when we start to lose sleep.

我們知道，這個程序在我們睡覺的時候進行，以清除神經系統白天的損耗，但目前似乎我們睡眠不足的時候也會進行相同的程序。

But rather than being a good thing, the brain goes overboard with the clearing, and starts to harm itself instead.

然而，這並不是什麼好事，大腦會過度清除細胞，而且開始傷害自己。

Think of it like the garbage being cleared out while you're asleep, versus someone coming into your house after several sleepless nights and indiscriminately tossing out your television, fridge, and family dog.

想一想，這就像你睡覺的時候垃圾桶被清空了，而在你失眠了幾個晚上之後，有人來到你家裏，恣意地扔掉了你的電視、冰箱和家裏養的小狗。

（翻譯：Dlacus）