英语听力文摘 English Digest 729 为什么我们要睡觉？（在线收听）

Why Do We Sleep?

Dear A Moment of Science,

Why do we sleep? I know this question has been debated by scientists and philosophers for centuries, but are there any hard and fast answers?

Good question! First, it’s true that scientists have long pondered the mystery of sleep why we do it and why it’s necessary. We know that going without sleep for too long can seriously damage health, so there’s good reason to believe that getting enough sleep is important for our well-being.

But exactly how and why that’s the case is still an open question. Some research, though, may shed a little light on the problem. For instance, scientists at the University of Rochester Medical Center in New York did a study with mice, and found that during sleep their brains flush out toxins that accumulate during the day.

More specifically, the study found that sleep sort of changes the brain’s cellular structure. When the mice were asleep or anesthetized, the researchers found that there was more space between their brain cells, allowing a sort of brain plumbing apparatus called the glymphatic system to open wide and allow fluid to flow quickly through the brain.

Other studies have shown that toxic molecules build up in the space between brain cells. Researchers at the University of Rochester found that those molecules vanished faster from the brain when the mice were asleep.

So what does this mean? Well, it could give scientists new ways to study and potentially treat brain disorders like Alzheimer’s by targeting the glymphatic system and helping it better flush away brain toxins.

我们为什么要睡觉？

亲爱的科学时刻：

我们为什么要睡觉？我知道这个问题已经被科学家和哲学家们争论了几个世纪，但有什么快速而有力的答案吗？

好问题！首先，科学家们长期以来一直在思考睡眠的奥秘，为什么我们要这样做，为什么有必要这样做。我们知道长时间不睡觉会严重损害健康，所以有充分的理由相信充足的睡眠对我们的健康很重要。

但究竟是如何以及为什么会这样，仍然是一个悬而未决的问题。不过，一些研究可能会对这个问题有一点帮助。例如，纽约罗切斯特大学医学中心的科学家对老鼠进行了一项研究，发现在睡眠中，老鼠的大脑会排出白天积聚的毒素。

更具体地说，研究发现睡眠会改变大脑的细胞结构。当小鼠处于睡眠或麻醉状态时，研究人员发现它们的脑细胞之间有更多的空间，这使得一种叫做glymphatic系统的大脑管道设备能够打开得很宽，让液体快速流过大脑。

其他研究表明，有毒分子在脑细胞之间的空间中积聚。罗切斯特大学的研究人员发现，当老鼠睡着时，这些分子从大脑中消失得更快。

那么这意味着什么呢？好吧，它可以为科学家提供新的方法来研究和潜在地治疗阿尔茨海默病等大脑疾病，通过靶向glymphatic系统，帮助其更好地清除大脑毒素。