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  • Sleep. It's something we spend about a third of our lives doing,

    睡眠,我們花三分之一的人生在睡覺

  • but do any of us really understand what it's all about?

    但有人知道睡眠到底對我們有什麼幫助嗎?

  • Two thousand years ago, Galen, one of the most prominent medical researchers of the ancient world,

    兩千年前,世界醫學研究權威,Galen

  • proposed that while we're awake, our brain's motive force, its juice, would flow out to all the other parts of the body,

    曾提出人類清醒時,頭腦的動力來源,腦汁,會擴散到全身各部位

  • animating them but leaving the brain all dried up,

    讓全身活起來,只剩腦部沒有腦汁

  • and he thought that when we sleep, all this moisture that filled the rest of the body would come rushing back,

    他還提出,人類睡覺時,分布全身的腦汁都會流回腦部

  • rehydrating the brain and refreshing the mind. Now, that sounds completely ridiculous to us now,

    使腦部再次濕潤,提起精神。我們現在聽了會覺得非常荒謬

  • but Galen was simply trying to explain something about sleep that we all deal with every day.

    但Galen只是在解釋我們每天都需要的睡眠

  • See, we all know based on our own experience that when you sleep, it clears your mind,

    我們都知道睡覺可以消除疲累

  • and when you don't sleep, it leaves your mind murky.

    但如果不睡覺,你的思緒就會不清楚

  • But while we know a great deal more about sleep now than when Galen was around,

    但我們比Galen更了解睡眠時

  • we still haven't understood why it is that sleep, of all of our activities, has this incredible restorative function for the mind.

    我們其實還搞不清楚人類為什麼需要睡眠,才能恢復體力,完成所有工作

  • So today I want to tell you about some recent research that may shed new light on this question.

    今天,我想要告訴你有關這個問題的近期研究

  • We've found that sleep may actually be a kind of elegant design solution to some of the brain's most basic needs,

    我們已經發現睡眠是提供腦部最基本需求的一種方法

  • a unique way that the brain meets the high demands and the narrow margins that set it apart from all the other organs of the body.

    大腦用這種獨特的方式滿足需求,所以能在所有器官中鶴立雞群

  • So almost all the biology that we observe can be thought of as a series of problems and their corresponding solutions,

    所以幾乎所有我們注意到的生物都有一系列的問題及解決方式

  • and the first problem that every organ must solve is a continuous supply of nutrients to fuel all those cells of the body.

    而每個器官首要解決的問題就是持續供應所有細胞營養

  • In the brain, that is especially critical;

    腦部是最重要的器官

  • its intense electrical activity uses up a quarter of the body's entire energy supply,

    雖然腦部只佔全身百分之二的重量

  • even though the brain accounts for only about two percent of the body's mass.

    但強烈的腦電活動卻耗用了全身四分之一的能量

  • So the circulatory system solves the nutrient delivery problem by sending blood vessels

    所以循環系統利用血管解決了營養傳送的問題

  • to supply nutrients and oxygen to every corner of our body.

    輸送養分和氧氣到全身各部位

  • You can actually see it in this video here. Here, we're imaging blood vessels in the brain of a living mouse.

    你們可以從影片這裡看到,我們正在放一部老鼠頭腦裡面的血管影像

  • The blood vessels form a complex network that fills the entire brain volume.

    血管築起一道複雜的網絡,以填滿整個腦部

  • They start at the surface of the brain, and then they dive down into the tissue itself,

    他們從腦部表面著手,再迅速進入腦組織裡

  • and as they spread out, they supply nutrients and oxygen to each and every cell in the brain.

    擴散的時候,他們會供應養分和氧氣給每一個腦細胞

  • Now, just as every cell requires nutrients to fuel it,

    每個細胞需要足夠養分才能刺激成長

  • every cell also produces waste as a byproduct,

    它們同時也會製造出副產品這種廢物

  • and the clearance of that waste is the second basic problem that each organ has to solve.

    而如何清理廢物是每個器官都要解決的次要基本問題

  • This diagram shows the body's lymphatic system, which has evolved to meet this need.

    這個圖表顯示了身體中的淋巴系統可以解決這個問題

  • It's a second parallel network of vessels that extends throughout the body.

    淋巴系統是第二條貫穿全身的血管

  • It takes up proteins and other waste from the spaces between the cells,

    它會吸收細胞間的蛋白質和其他廢物

  • it collects them, and then dumps them into the blood so they can be disposed of.

    它先收集它們,再一起倒入血液中,把它們清除乾淨

  • But if you look really closely at this diagram, you'll see something that doesn't make a lot of sense.

    但如果你再看清楚一點,你會發現那不合常理

  • So if we were to zoom into this guy's head, one of the things that you would see there is that there are no lymphatic vessels in the brain.

    我們近看這個人的腦部,你會發現腦部根本沒有淋巴系統

  • But that doesn't make a lot of sense, does it?

    那實在不合常理,對不對?

  • I mean, the brain is this intensely active organ that produces a correspondingly large amount of waste that must be efficiently cleared.

    腦部是非常活躍的器官,它也會製造出大量需要被清除的廢物

  • And yet, it lacks lymphatic vessels, which means that the approach that the rest of the body takes to clearing away its waste won't work in the brain.

    然而,腦部缺少了淋巴系統,就代表其他器官清除身體廢物的方式,不適用於腦部

  • So how, then, does the brain solve its waste clearance problem?

    到底腦部如何解決廢物清理的問題呢?

  • Well, that seemingly mundane question is where our group first jumped into this story,

    這看似稀鬆平常的問題是我們團隊著手的第一步

  • and what we found as we dove down into the brain, down among the neurons and the blood vessels,

    我們研究腦部時,發現神經元和血管下面

  • was that the brain's solution to the problem of waste clearance, it was really unexpected.

    就是腦部解決廢物清除問題的所在之處,我們完全沒想到會在這裡

  • It was ingenious, but it was also beautiful. Let me tell you about what we found.

    它非常精緻,也非常漂亮,我告訴你們我們發現了什麼

  • So the brain has this large pool of clean, clear fluid called cerebrospinal fluid.

    腦部有個大型廢物處理槽,它叫作腦脊液蛋白

  • We call it the CSF. The CSF fills the space that surrounds the brain,

    我們簡稱為CSF,CSF包圍著大腦

  • and wastes from inside the brain make their way out to the CSF, which gets dumped, along with the waste, into the blood

    腦中的廢物被送到CSF,然後廢物隨著CSF排入血液中

  • So in that way, it sounds a lot like the lymphatic system, doesn't it?

    如此一來,它的功能就像淋巴系統一樣了,對吧?

  • But what's interesting is that the fluid and the waste from inside the brain,

    但有趣的是,腦部的廢物和液體

  • they don't just percolate their way randomly out to these pools of CSF.

    不會隨便被過濾到CSF中

  • Instead, there is a specialized network of plumbing that organizes and facilitates this process.

    反而有特殊的配管網絡,有系統地處理這項程序

  • You can see that in these videos. Here, we're again imaging into the brain of living mice.

    你可以從這些影像上看到,現在,我們再次觀看老鼠頭腦內的血管影像

  • The frame on your left shows what's happening at the brain's surface,

    左畫面顯示的是腦部表面

  • and the frame on your right shows what's happening down below the surface of the brain within the tissue itself.

    而右手邊的畫面,顯示了腦表面下的組織

  • We've labeled the blood vessels in red, and the CSF that's surrounding the brain will be in green.

    我們把紅色當作血管,綠色當作腦部周圍的CSF

  • Now, what was surprising to us was that the fluid on the outside of the brain, it didn't stay on the outside.

    現在,我們很驚訝腦部外面的液體竟然不在腦部外面

  • Instead, the CSF was pumped back into and through the brain along the outsides of the blood vessels,

    CSF反而順著腦部外面的血管一起注入腦部

  • and as it flushed down into the brain along the outsides of these vessels,

    而且它和腦部外面的血管一起被沖入腦部時

  • it was actually helping to clear away, to clean the waste from the spaces between the brain's cells.

    確實能清理腦細胞間的廢物

  • If you think about it, using the outsides of these blood vessels like this is a really clever design solution,

    你仔細想想,會覺得利用腦部外的血管確實是個清除廢物的好辦法

  • because the brain is enclosed in a rigid skull and it's packed full of cells,

    因為腦部被堅硬的頭蓋骨蓋住,而且裡面有大量細胞

  • so there is no extra space inside it for a whole second set of vessels like the lymphatic system.

    所以沒有空間放像淋巴系統這樣的血管

  • Yet the blood vessels, they extend from the surface of the brain down to reach every single cell in the brain,

    然而,血管從腦部表面延伸到腦部裡面的每個細胞

  • which means that fluid that's traveling along the outsides of these vessels can gain easy access to the entire brain's volume,

    那表示流動在血管外的液體可以更容易進入整個腦部

  • so it's actually this really clever way to repurpose one set of vessels,

    所以它其實用一個非常聰明的方法,重複利用一副血管來清除腦部廢物

  • the blood vessels, to take over and replace the function of a second set of vessels, the lymphatic vessels, to make it so you don't need them.

    來占據和取代淋巴系統的功能,所以你不需要淋巴系統

  • And what's amazing is that no other organ takes quite this approach to clearing away the waste from between its cells.

    令人吃驚的是,沒有其他器官用這種方式來清除細胞間的廢物

  • This is a solution that is entirely unique to the brain.

    這是腦部獨特的清理方式

  • But our most surprising finding was that all of this, everything I just told you about,

    但我們發現最出乎意料的是我告訴你們的每件事

  • with all this fluid rushing through the brain, it's only happening in the sleeping brain.

    有關液體流經腦部的事,都只發生在睡眠中的腦部

  • Here, the video on the left shows how much of the CSF is moving through the brain of a living mouse while it's awake.

    這裡,左邊的影片顯示了當我們清醒時,有多少CSF像活老鼠一般流經腦部

  • It's almost nothing. Yet in the same animal, if we wait just a little while until it's gone to sleep,

    答案是幾乎沒有,然而,同一種動物,如果等牠睡著

  • what we see is that the CSF is rushing through the brain, and we discovered that at the same time when the brain goes to sleep,

    我們會看到CSF流經腦部,同時我們會發現腦部休眠時

  • the brain cells themselves seem to shrink, opening up spaces in between them, allowing fluid to rush through and allowing waste to be cleared out.

    腦細胞會不停地收縮,讓液體流經並清除廢物

  • So it seems that Galen may actually have been sort of on the right track

    所以當Galen寫到睡覺時,液體會流經腦部

  • when he wrote about fluid rushing through the brain when sleep came on.

    的想法可能是正確的

  • Our own research, now it's 2,000 years later, suggests that what's happening is that when the brain is awake and is at its most busy,

    我們的研究,現在已經是兩千年後了,提出了人類清醒時,腦部最忙碌的理論

  • it puts off clearing away the waste from the spaces between its cells until later,

    它延後清除細胞間的廢物

  • and then, when it goes to sleep and doesn't have to be as busy,

    之後,睡覺時,腦部就不會那麼忙碌了

  • it shifts into a kind of cleaning mode to clear away the waste from the spaces between its brain,

    它轉變成在清除腦細胞間廢物

  • the waste that's accumulated throughout the day.

    清除那些累積一整天的廢物

  • So it's actually a little bit like how you or I,

    其實它有點像你我

  • we put off our household chores during the work week when we don't have time to get to it,

    我們把家事拖到周末才做,因為平日我們沒有時間處理

  • and then we play catch up on all the cleaning that we have to do when the weekend rolls around.

    周末時,我們才把所有打掃的進度都補上

  • Now, I've just talked a lot about waste clearance,

    我已經說了那麼多有關清除廢物的事,

  • but I haven't been very specific about the kinds of waste that the brain needs to be clearing during sleep in order to stay healthy.

    但我還沒有詳細說明到底腦部的哪種廢物需要在睡覺時被清除,才能保持健康

  • The waste product that these recent studies focused most on is amyloid-beta, which is a protein that's made in the brain all the time.

    近期比較多學者研究澱粉樣蛋白,這種廢物一直都在腦中

  • My brain's making amyloid-beta right now, and so is yours.

    現在,我的頭腦正在製造澱粉樣蛋白,你們的也是

  • But in patients with Alzheimer's disease, amyloid-beta builds up and aggregates in the spaces between the brain's cells,

    但在阿茲海默病患的腦中,澱粉樣蛋白聚集在腦細胞間

  • instead of being cleared away like it's supposed to be,

    而不是正常地被清除乾淨

  • and it's this buildup of amyloid-beta that's thought to be one of the key steps in the development of that terrible disease.

    這種澱粉樣蛋白的累積被視為成為嚴重疾病的關鍵

  • So we measured how fast amyloid-beta is cleared from the brain when it's awake versus when it's asleep,

    所以我們測試清醒時和睡眠時澱粉樣蛋白能多快被清除乾淨

  • and we found that indeed, the clearance of amyloid-beta is much more rapid from the sleeping brain.

    我們發現,在睡覺時清除澱粉樣蛋白的速度比較快

  • So if sleep, then, is part of the brain's solution to the problem of waste clearance,

    所以如果睡眠是腦部清除廢物的辦法之一

  • then this may dramatically change how we think about the relationship between sleep, amyloid-beta, and Alzheimer's disease.

    那這會戲劇性地改變我們對睡眠、澱粉類蛋白和阿茲海默症的關係

  • A series of recent clinical studies suggest that among patients who haven't yet developed Alzheimer's disease,

    最近一系列臨床調查顯示還沒有得到阿茲海默症的病人

  • worsening sleep quality and sleep duration are associated with a greater amount of amyloid-beta building up in the brain,

    睡眠品質都會下降,睡眠時間和腦部累積的澱粉類蛋白有極大的關係

  • and while it's important to point out that these studies don't prove that lack of sleep or poor sleep cause Alzheimer's disease,

    這些研究無法證實缺乏睡眠或睡眠品質不好會造成阿茲海默症

  • they do suggest that the failure of the brain to keep its house clean

    但他們卻提出腦部無法將

  • by clearing away waste like amyloid-beta may contribute to the development of conditions like Alzheimer's.

    澱粉類蛋白這種廢物清除乾淨可能會引發阿茲海默症

  • So what this new research tells us, then, is that the one thing that all of you already knew about sleep,

    所以這項新研究到底告訴我們什麼事情呢?其實大家都很熟悉

  • that even Galen understood about sleep, that it refreshes and clears the mind,

    Galen也了解睡眠可以讓頭腦清醒

  • may actually be a big part of what sleep is all about.

    確實是睡眠的重要因素

  • See, you and I, we go to sleep every single night, but our brains, they never rest.

    你們和我,我們每天晚上都需要睡覺,但我們的頭腦,他們從來不休息

  • While our body is still and our mind is off walking in dreams somewhere,

    我們的身體靜止不動、我們的心也被夢偷走時

  • the elegant machinery of the brain is quietly hard at work cleaning and maintaining this unimaginably complex machine.

    腦中最優雅的裝置正靜靜地清除廢物,並維持這個令人難以想像的複雜裝置

  • Like our housework, it's a dirty and a thankless job, but it's also important.

    就像我們的家事,它是個又髒又得不到獎勵的工作,但它非常重要

  • In your house, if you stop cleaning your kitchen for a month, your home will become completely unlivable very quickly.

    在家裡,如果你一個月不打掃廚房,你們家一定馬上就髒到不能住人

  • But in the brain, the consequences of falling behind may be much greater than the embarrassment of dirty countertops,

    但在腦中,落後的清掃工作可能還比骯髒的工作平台還要嚴重

  • because when it comes to cleaning the brain, it is the very health and function of the mind and the body that's at stake,

    因為清掃腦部時,它代表了頭腦的健康和功能,也代表身體正在冒風險

  • which is why understanding these very basic housekeeping functions of the brain today may be critical for preventing and treating diseases of the mind tomorrow.

    所以為什麼了解腦部這些基本打掃功能會那麼重要,能保護我們遠離腦部疾病

  • Thank you.

    謝謝大家

Sleep. It's something we spend about a third of our lives doing,

睡眠,我們花三分之一的人生在睡覺

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B1 中級 中文 美國腔 TED 腦部 廢物 清除 睡眠 血管

【TED】每天都要好好睡覺的另一個原因 Jeff Iliff: One more reason to get a good night's sleep

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    Go Tutor 發佈於 2014 年 11 月 18 日
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