Carl Schoonover: How to look inside the brain

翻译人员: Jia Zeng 校对人员: Yuguo Zhang

This is a thousand-year-old drawing of the brain.

这是一张一千年前关于大脑的绘画

It's a diagram of the visual system.

一个关于视觉系统的图像

And some things look very familiar today.

有些东西在今天看来也很熟悉

Two eyes at the bottom, optic nerve flowing out from the back.

底下是两只眼睛，视觉神经从它们后面伸出来

There's a very large nose

这是个很大的鼻子

that doesn't seem to be connected to anything in particular.

看起来它并没有连接到特殊的部位

And if we compare this

如果我们把这个

to more recent representations of the visual system,

跟最近的视觉系统的表现形式进行对比

you'll see that things have gotten substantially more complicated

你会发现情况变得异常复杂

over the intervening thousand years.

在经历了几千年之后

And that's because today we can see what's inside of the brain,

这是因为今天我们可以看见大脑里面的东西

rather than just looking at its overall shape.

而不只是它大致的形状

Imagine you wanted to understand how a computer works

想象下如果你想知道电脑是如何工作的

and all you could see was a keyboard, a mouse, a screen.

你能看到的只是键盘，鼠标和屏幕

You really would be kind of out of luck.

你真的不会那么走运（明白它是怎么工作的）

You want to be able to open it up, crack it open,

你会想要打开它，拆开它

look at the wiring inside.

看看里面电线的连接

And up until a little more than a century ago,

直到一百多年以前

nobody was able to do that with the brain.

没有人能够这样对待大脑

Nobody had had a glimpse of the brain's wiring.

没人看到过大脑的回路

And that's because if you take a brain out of the skull

那是因为如果你把大脑从头盖骨里拿出来

and you cut a thin slice of it,

从中切出一个薄片

put it under even a very powerful microscope,

把它放在即便很强大的显微镜下面

there's nothing there.

那里什么都没有

It's gray, formless.

它是灰色的，没有固定形状

There's no structure. It won't tell you anything.

没有结构。它不会告诉你任何东西

And this all changed in the late 19th century.

这些都在19世纪末发生了改变

Suddenly, new chemical stains for brain tissue were developed

忽然间，人们发明了新的大脑组织的化学染料

and they gave us our first glimpses at brain wiring.

这些染料让我们第一次看到大脑的回路

The computer was cracked open.

这个电脑被打开了

So what really launched modern neuroscience

真正开启现代神经科学的是

was a stain called the Golgi stain.

一种叫高尔基染色法的染料

And it works in a very particular way.

它工作原理很特别

Instead of staining all of the cells inside of a tissue,

它并不是对组织里面的所有细胞进行染色

it somehow only stains about one percent of them.

而是只染对其中大约1%的细胞

It clears the forest, reveals the trees inside.

它清除了森林的图像，展现了其中的树木

If everything had been labeled, nothing would have been visible.

如果所有东西都被标记上的话，那什么都看不见了

So somehow it shows what's there.

所有它以某种方式展示了大脑里的东西

Spanish neuroanatomist Santiago Ramon y Cajal,

西班牙神经解剖学家圣地亚哥·拉蒙-卡哈尔

who's widely considered the father of modern neuroscience,

被普遍认为是现代神经科学之父

applied this Golgi stain, which yields data which looks like this,

他用高尔基染色法展示了这样的图像

and really gave us the modern notion of the nerve cell, the neuron.

这给了我们神经细胞，神经元的现代概念

And if you're thinking of the brain as a computer,

如果你把大脑想象成一个电脑

this is the transistor.

这就是晶体管

And very quickly Cajal realized

卡哈尔很快意识到

that neurons don't operate alone,

神经元不是单独工作的

but rather make connections with others

而是与其它神经元互相连接

that form circuits just like in a computer.

形成像电脑一样的电路

Today, a century later, when researchers want to visualize neurons,

今天，一个世纪之后，当研究人员想要看神经元的时候

they light them up from the inside rather than darkening them.

他们从内部点亮神经元，而不是让它们变暗

And there's several ways of doing this.

它有几种做法

But one of the most popular ones

最流行的做法之一

involves green fluorescent protein.

要用到荧光蛋白

Now green fluorescent protein,

现在，绿色荧光蛋白

which oddly enough comes from a bioluminescent jellyfish,

一种来自生物发光的水母中的荧光蛋白

is very useful.

很有用处

Because if you can get the gene for green fluorescent protein

因为如果你能得到绿色荧光蛋白的基因

and deliver it to a cell,

并把它运入一个细胞

that cell will glow green --

那个细胞就会发出绿色荧光——

or any of the many variants now of green fluorescent protein,

如果你使用任何这种绿色荧光蛋白的变体

you get a cell to glow many different colors.

你可以让一个细胞发出不同的颜色的荧光

And so coming back to the brain,

回到大脑的话题

this is from a genetically engineered mouse called "Brainbow."

有一种叫“大脑彩虹”的转基因小鼠

And it's so called, of course,

人们这样叫它

because all of these neurons are glowing different colors.

当然是因为这些神经元在发出不同颜色的荧光

Now sometimes neuroscientists need to identify

现在，神经科学家们有时候需要识别

individual molecular components of neurons, molecules,

神经元的特定分子元件

rather than the entire cell.

识别分子，而不是整个细胞

And there's several ways of doing this,

这可以通过好几种方法做到

but one of the most popular ones

但是最流行的方法之一

involves using antibodies.

用到了抗体

And you're familiar, of course,

你们一定

with antibodies as the henchmen of the immune system.

对作为免疫系统的抗体十分熟悉

But it turns out that they're so useful to the immune system

实际上它们在免疫系统中如此重要的原因是

because they can recognize specific molecules,

它们可以识别特定的分子

like, for example, the coat protein

比如一个入侵身体的病毒的

of a virus that's invading the body.

外壳蛋白

And researchers have used this fact

研究人员利用抗体的这个特性

in order to recognize specific molecules inside of the brain,

来识别大脑内部的特定分子

recognize specific substructures of the cell

识别细胞的特定亚结构

and identify them individually.

并将它们逐个分辨出来

And a lot of the images I've been showing you here are very beautiful,

我在这展示的很多图像都很漂亮

but they're also very powerful.

但它们同时也很强大

They have great explanatory power.

它们可以解释很多东西

This, for example, is an antibody staining

比如说，这是一个

against serotonin transporters in a slice of mouse brain.

针对小鼠大脑切片里5-羟色胺转运体的抗体染色图象

And you've heard of serotonin, of course,

你们肯定听说过5-羟色胺

in the context of diseases like depression and anxiety.

它与忧虑、焦虑一类的疾病有关

You've heard of SSRIs,

你们也听说过 SSRIs (选择性5-羟色胺再摄取抑制剂)

which are drugs that are used to treat these diseases.

它被用来治疗以上几种疾病

And in order to understand how serotonin works,

如果想了解5-羟色胺是怎么起作用的

it's critical to understand where the serontonin machinery is.

我们必须先明白5-羟色胺作用的部位在哪里

And antibody stainings like this one

而我们可以通过这样的抗体染色

can be used to understand that sort of question.

来解答类似的问题

I'd like to leave you with the following thought:

我想给你们留下这样一个信息：

Green fluorescent protein and antibodies

绿色荧光蛋白和抗体

are both totally natural products at the get-go.

最早都是自然产物

They were evolved by nature

它们通过自然进化

in order to get a jellyfish to glow green for whatever reason,

以便使一个水母不论以什么原因发出绿色荧光

or in order to detect the coat protein of an invading virus, for example.

或是以便识别入侵身体的病毒的外壳蛋白

And only much later did scientists come onto the scene

过了很久很久以后，科学家才出场

and say, "Hey, these are tools,

说：“这些都是工具，

these are functions that we could use

我们可以把这些功能

in our own research tool palette."

用到我们自己的研究工具控制板上。”

And instead of applying feeble human minds

与其用有限的人类智慧

to designing these tools from scratch,

来从头设计工具

there were these ready-made solutions right out there in nature

不如用这些在自然界中

developed and refined steadily for millions of years

经过几百万年的发展、改善并稳定下来的现成的工具来解答

by the greatest engineer of all.

它们是大自然的鬼斧神工

Thank you.

谢谢

(Applause)

（掌声）