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.
人们对睡眠的需求不仅仅是为了每12个小时补充一下体力。实际上，我们睡觉的时候，大脑会改变状态，清除白天神经活动留下的有毒副产物。

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，长期睡眠不足，大脑内也会进行这样的程序，只是它会进入过度清除状态。

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.
研究人员发现，长期睡眠不足会使大脑清除大量神经元和突触连接，而且恢复睡眠也许并不能彻底修复损伤。

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.
意大利马尔理工大学神经科学家米歇尔·贝蕾西带领的团队研究了哺乳动物的大脑对睡眠不足的反应，他们发现休息时间充足的小鼠与睡眠不足的小鼠之间有古怪的相似性。

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.
就像你身体其他部位的细胞一样，你大脑里的神经元也在不断被两种不同的神经胶质细胞所更新，这些支持细胞经常被称为神经系统的粘合剂。

The microglial cells are responsible for clearing out old and worn out cells via a process called phagocytosis - meaning "to devour" in Greek.
这种微神经胶质细胞通过一个被称为吞噬现象（phagocytosis在希腊语中是“吞噬”的意思）的过程来清除老细胞和衰竭的细胞。

The astrocytes' job is to prune unnecessary synapses (connections) in the brain to refresh and reshape its wiring.
星型胶质细胞的作用是清除大脑中不必要的突触（连接）来恢复并重塑它的神经网络。

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.
我们知道，这个程序在我们睡觉的时候进行，以清除神经系统白天的损耗，但目前似乎我们睡眠不足的时候也会进行相同的程序。

But rather than being a good thing, the brain goes overboard with the clearing, and starts to harm itself instead.
然而，这并不是什么好事，大脑会过度清除细胞，而且开始伤害自己。

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，这就像你睡觉的时候垃圾桶被清空了，而在你失眠了几个晚上之后，有人来到你家里，恣意地扔掉了你的电视、冰箱和家里养的小狗。

 

（翻译：Dlacus）