Carl Schoonover: How to look inside the brain

74,199 views ・ 2012-05-17

TED


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譯者: Dennis Guo 審譯者: Chen-Han Hsiao
00:15
This is a thousand-year-old drawing of the brain.
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這個大腦的繪圖有一千年的歷史。
00:19
It's a diagram of the visual system.
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它畫的是視覺系統,
00:21
And some things look very familiar today.
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即使在幾天也看起來有些眼熟。
00:24
Two eyes at the bottom, optic nerve flowing out from the back.
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兩個眼睛在下面,視神經將它們連接著後面。
00:28
There's a very large nose
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它有一個似乎沒有和任何
00:30
that doesn't seem to be connected to anything in particular.
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東西連接起來的很大的鼻子。
00:34
And if we compare this
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而如果我們將它與
00:35
to more recent representations of the visual system,
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一些最近的視覺系統的描繪做比較的話,
00:37
you'll see that things have gotten substantially more complicated
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你會看到在過去的幾千年中
00:40
over the intervening thousand years.
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很多東西都變的更為複雜了。
00:42
And that's because today we can see what's inside of the brain,
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由過去只能在外面看著大概的輪廓,
00:45
rather than just looking at its overall shape.
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今天我們能直接觀察大腦內部。
00:47
Imagine you wanted to understand how a computer works
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想像一下如果你想明白一個電腦是如何工作的,
00:51
and all you could see was a keyboard, a mouse, a screen.
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但你這能看到一個鍵盤,一個滑鼠,一個顯示屏。
00:54
You really would be kind of out of luck.
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那你真的滿不幸的。
00:57
You want to be able to open it up, crack it open,
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你會想把它打開,
00:59
look at the wiring inside.
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然後觀察內部。
01:01
And up until a little more than a century ago,
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而直到一個多世紀之前,
01:03
nobody was able to do that with the brain.
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沒有人可以如此對待大腦。
01:05
Nobody had had a glimpse of the brain's wiring.
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哪怕是一絲大腦線路的知識也沒有人有。
01:07
And that's because if you take a brain out of the skull
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而那是因為如果你把大腦從頭骨中取出後
01:09
and you cut a thin slice of it,
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並且將它切成薄片,
01:11
put it under even a very powerful microscope,
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然後放在最大功率的顯微鏡下,
01:14
there's nothing there.
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你也不會看到任何東西。
01:15
It's gray, formless.
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它是形體不明的一片灰色。
01:16
There's no structure. It won't tell you anything.
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你看不到結構。它不能告訴你任何東西。
01:19
And this all changed in the late 19th century.
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而這在十九世紀後期全部都改變了。
01:22
Suddenly, new chemical stains for brain tissue were developed
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突然,新的大腦組織的化學染料被開發了出來,
01:26
and they gave us our first glimpses at brain wiring.
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讓我們第一次能夠看到大腦的線路。
01:29
The computer was cracked open.
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電腦被解讀了。
01:31
So what really launched modern neuroscience
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而真正開始了現代神經學的是一個
01:33
was a stain called the Golgi stain.
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叫做高爾基染色法的染料。
01:35
And it works in a very particular way.
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而它以一種特殊的方式起它的作用。
01:37
Instead of staining all of the cells inside of a tissue,
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它只會染一片組織中大概百分之一的細胞,
01:40
it somehow only stains about one percent of them.
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而不是染全部細胞。
01:43
It clears the forest, reveals the trees inside.
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它在大森林中顯現出幾棵樹。
01:47
If everything had been labeled, nothing would have been visible.
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如果所有東西都被染上,那其實什麽東西也看不到。
01:49
So somehow it shows what's there.
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而它用某種方式展現了它的功能。
01:52
Spanish neuroanatomist Santiago Ramon y Cajal,
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西班牙的神經解剖學專家 聖地亞哥·拉蒙-卡哈爾
01:54
who's widely considered the father of modern neuroscience,
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被普遍稱為現代神經學之父,
01:57
applied this Golgi stain, which yields data which looks like this,
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他使用了高爾基染法並展現了如此一般的信息,
02:01
and really gave us the modern notion of the nerve cell, the neuron.
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而這給了我們神經細胞,神經元,的現代概念。
02:05
And if you're thinking of the brain as a computer,
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而如果你把大腦想成一個電腦,
02:07
this is the transistor.
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它便是電晶體。
02:09
And very quickly Cajal realized
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很快的,卡哈爾意識到
02:11
that neurons don't operate alone,
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神經元並不單獨的運作,
02:14
but rather make connections with others
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而是與其他神經元連成
02:16
that form circuits just like in a computer.
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像電腦一樣的電路。
02:18
Today, a century later, when researchers want to visualize neurons,
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在一個世紀後的今天,當研究員們想要看神經元的時候,
02:21
they light them up from the inside rather than darkening them.
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他們將它們從內部亮起,而不是使它們變的更暗。
02:24
And there's several ways of doing this.
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它有幾種方法。
02:25
But one of the most popular ones
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但最受歡迎的一個
02:27
involves green fluorescent protein.
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要用到螢光蛋白。
02:29
Now green fluorescent protein,
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這種從一種生物發光的海蜇中
02:31
which oddly enough comes from a bioluminescent jellyfish,
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得來的綠色螢光蛋白
02:34
is very useful.
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非常的有用。
02:35
Because if you can get the gene for green fluorescent protein
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因為如果你能夠得到這種綠色螢光蛋白的基因
02:38
and deliver it to a cell,
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並將它植入一個細胞,
02:40
that cell will glow green --
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這個細胞會發出綠色的螢光 --
02:41
or any of the many variants now of green fluorescent protein,
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如果你使用綠色螢光蛋白的其他變體,
02:45
you get a cell to glow many different colors.
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你可以讓細胞發出不同顏色的螢光。
02:47
And so coming back to the brain,
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回到大腦,
02:48
this is from a genetically engineered mouse called "Brainbow."
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這是從一個叫做“腦虹”的改基因老鼠。
02:52
And it's so called, of course,
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這是因為,當然,
02:54
because all of these neurons are glowing different colors.
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所有的這些神經元都在發出不同顏色的螢光。
02:57
Now sometimes neuroscientists need to identify
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有些時候神經學家需要識別出
03:01
individual molecular components of neurons, molecules,
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特定的神經元的分子部構,
03:04
rather than the entire cell.
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而不是整個細胞。
03:05
And there's several ways of doing this,
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這也有幾種方式可以達成,
03:07
but one of the most popular ones
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但最受歡迎的一種
03:09
involves using antibodies.
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使用到了抗體。
03:11
And you're familiar, of course,
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你肯定對於
03:12
with antibodies as the henchmen of the immune system.
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免疫系統的抗體非常熟悉。
03:15
But it turns out that they're so useful to the immune system
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而它們在免疫系統中如此的重要是
03:18
because they can recognize specific molecules,
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因為它們可以識別特定的分子,
03:20
like, for example, the coat protein
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比如一個侵入身體的病毒
03:22
of a virus that's invading the body.
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的外層蛋白。
03:25
And researchers have used this fact
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研究員們用這種功能
03:27
in order to recognize specific molecules inside of the brain,
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來識別大腦中特定的分子,
03:31
recognize specific substructures of the cell
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或者認出細胞的特定結構
03:34
and identify them individually.
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并單獨的識別它們。
03:36
And a lot of the images I've been showing you here are very beautiful,
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我展示的很多的圖像都非常美麗,
03:39
but they're also very powerful.
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但它們同時也很厲害。
03:41
They have great explanatory power.
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它們可以解釋很多東西。
03:42
This, for example, is an antibody staining
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比如說這個,它是經過對血清素運輸分子的
03:45
against serotonin transporters in a slice of mouse brain.
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抗體染色的的一片老鼠大腦。
03:48
And you've heard of serotonin, of course,
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你應該在談論像憂鬱和焦慮癥一樣的病時
03:50
in the context of diseases like depression and anxiety.
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聽說過血清素。
03:53
You've heard of SSRIs,
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你也聽說過 SSRIs(選擇性血清素回收抑制劑),
03:54
which are drugs that are used to treat these diseases.
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這種藥物被用來治療這些病。
03:57
And in order to understand how serotonin works,
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而如果想明白血清素是怎麼起作用的,
04:00
it's critical to understand where the serontonin machinery is.
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我們必須先明白血清素的部位在哪裡。
04:03
And antibody stainings like this one
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而像這個的抗體染色
04:04
can be used to understand that sort of question.
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可以被用來解答類似的問題。
04:08
I'd like to leave you with the following thought:
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我想為你們留下這樣一個信息:
04:11
Green fluorescent protein and antibodies
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綠色螢光蛋白和抗體
04:13
are both totally natural products at the get-go.
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都是完全的自然產品。
04:16
They were evolved by nature
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它們從自然演化而來,
04:19
in order to get a jellyfish to glow green for whatever reason,
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以便讓一個海蜇因為一些原因可以發出綠色的螢光,
04:21
or in order to detect the coat protein of an invading virus, for example.
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或者來發現一個入侵的病毒的外層蛋白。
04:26
And only much later did scientists come onto the scene
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而在很久很久以後,科學家才發現
04:29
and say, "Hey, these are tools,
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並說,“這些都是工具,
04:31
these are functions that we could use
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我們可以把它們的功用
04:33
in our own research tool palette."
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加入到我們研究的手段中。”
04:35
And instead of applying feeble human minds
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而與其用有限的大腦來
04:39
to designing these tools from scratch,
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從頭設計這些工具,
04:41
there were these ready-made solutions right out there in nature
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這些被做好的答案已經出現在自然
04:43
developed and refined steadily for millions of years
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並用了幾百萬年的時間來發展和穩定下來。
04:47
by the greatest engineer of all.
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自然是最偉大的工程師。
04:48
Thank you.
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謝謝。
04:50
(Applause)
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(掌聲)
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