to paint a neural portrait of the human mind.

描繪大腦神經視圖

And the central idea of this work

這研究的中心思想是

is that the human mind and brain is not a single, general-purpose processor,

人類的思想與大腦 並非只是個通用型處理器

but a collection of highly specialized components,

而是高度專業化組件所形成的集合體

each solving a different specific problem,

每個組件都能用來解決特定問題

and yet collectively making up who we are as human beings and thinkers.

人類的思想便是由這些組件共同集合而成

To give you a feel for this idea, imagined the following scenario:

為了讓你們理解這個概念 來想像一下這個場景

You walk into your child's daycare center.

你走進了你小孩的托兒所中

As usual, there's a dozen kids there, waiting to get picked up.

像平常一樣 有十幾個小孩待在一起 等人來接

But this time, the children's faces look weirdly similar,

但這次 孩子們的臉看起來異常相似

and you can't figure out which child is yours.

你突然認不出自己的小孩

Do you need new glasses?

是該換眼鏡了嗎?

Are you losing your mind?

還是你瘋了?

You run through a quick mental checklist.

你在心裡快速自我檢驗一番

No, you seem to be thinking clearly,

不 你思緒清晰

and your vision is perfectly sharp.

視力依然良好

And everything looks normal, except the children's faces.

一切看起來都很正常 除了孩子的臉

You can see the faces, but they don't look distinctive,

你看著這些小臉 每張臉都很普通

and none of them looks familiar,

也都很陌生

and it's only by spotting an orange hair ribbon that you find your daughter.

最後 你靠著頭上的橘色蝴蝶結 認出自己的女兒

This sudden lost of the ability to recognize faces actually happens to people.

這種突發性的臉部辨識障礙 是真實病例

It's called prosopagnosia,

學名叫做 臉盲症

and it results from damage to a particular part of the brain.

是因大腦特定部位損傷所導致

The striking thing about it is that only face recognition is impaired,

臉盲症最特別的是 除了無法辨識人臉以外

everything else is just fine.

其他一切都很正常

So prosopagnosia is one of many surprisingly specific mental deficits that can happen after brain damage.

腦部受損後 可能會有各種奇特症狀 臉盲症只是其中之一

These syndromes collectively have suggested for a long time

長期以來 這種種症狀 都暗示著

that the mind is divvied up into distinct components,

大腦可分為數個不同的認知區域

but the effort to discover those components has jumped to warp speed

這些認知區域的研究 近來急速發展

with the invention of brain imaging technology,

這得歸功於大腦影像技術的發明

especially MRI.

特別是核磁共振技術

So MRI enables you to see internal anatomy at high resolution.

核磁共振能使人清晰看見人體內部結構

So I'm going to show you in a second

我等等會向各位展示

a set of MRI cross-sectional images through a familiar object,

一系列日常物品的核磁造影

and we're going to fly through them and you're going to try to figure out what the object is. Here we go.

我們會快速展示圖像 讓各位來猜猜這些是甚麼 開始

It's not that easy. It's an artichoke.

這不太容易 這是朝鮮薊

Okay let's try another one,

來試試下一個

starting from the bottom and going through the top.

從底部開始 一直到頂端

Broccoli! It's a head of broccoli. It's it beautiful? I love that.

花椰菜! 這是顆花椰菜 美吧? 我好愛這個

Okay here's another one.

好 下一個

It's a brain, of course. In fact, it's my brain.

很明顯 這是腦部 其實這是我的腦

We're going through slices through my head like that.

我們會像這樣看腦部剖面

That's my nose over on the right, and now we're going over here. Right there.

右邊是我的鼻子 現在正通過這裡 就是這

So this picture is nice,

所以…這是張優秀的圖

if I do say so myself.

我本人也是

But it shows only anatomy.

但這只展現了解剖構造

The really cool advance with functional imaging happened when scientists figured out

最酷的影像技術進展是 科學家研究出

how to make pictures that show not just anatomy but activity,

如何讓影像不再只顯現解剖構造 而是生物活動

that is, where neurons are firing.

也就是 顯示哪裡神經正在活躍

So here's how this works.

運作方法是這樣

Brains are like muscles. When they get active,

大腦 就像肌肉 開始活動時

they need increased blood flow to supply that activity,

會增加血液流量 維持活動所需

and lucky for us, blood flow control to the brain is local.

幸運的是 大腦自身能控制血液流量

So if a bunch of neurons, say, right there get active and start firing,

解設這裡有叢神經元開始運作 活躍起來

then blood flow increases just right there.

這裡的血液流量就會增加

So functional MRI picks up on that blood flow increase,

功能性的核磁共振偵測到血流增加

producing a higher MRI response where neural activity goes up.

顯示神經活動增加的具體位置

So to give you a concrete feel for how a functional MRI experiment goes

為了讓各位能具體理解功能性核磁共振實驗的進行

and what you can learn from it and what you can't,

了解它的能耐與限制

let me describe one of the first studies I ever did.

我來描述一個以前我進行過的研究

We wanted to know if there was a special part of the brain for recognizing faces,

當時我們想知道 某個大腦部位是不是專門用來辨識人臉

and there was already reason to think there might be such a thing

已經有足夠理由顯示 這可能是真的

based on this phenomenon of prosopagnosia that I described a moment ago.

也就是 基於我剛剛說到的臉盲症現象

But nobody had ever seen that part of the brain in a normal person,

但沒人在普通人的腦部看過這個部位

so we set out to look for it.

所以我們設計實驗來尋找它

So I was the first subject.

我是第一個受試者

I went into the scanner, I lay on my back,

我進去掃描儀中 躺了下來

I held my head as still as I could while staring at pictures of faces

頭像這樣保持不動 盯著一張張臉部照片

like these

像這些

and objects like these

還有物品 像這些

and faces… and objects… for hours.

看臉部…再看物品…看了好幾個小時

So as somebody who has pretty close to the world record of total number of hours spent inside a MRI scanner,

我在核磁共振裡的時間 久到快破世界紀錄

I can tell you that one of the skills that's really important for MRI research

所以我敢告訴你 從事核磁共振研究的必備技能之一是

is bladder control.

控制膀胱

When I got out of the scanner, I did a quick analysis of the data,

我踏出掃描儀後 將資料快速進行分析

looking for any parts of my brain that produced a higher response when I was looking at faces than when I was looking at objects,

尋找看著臉部時 大腦反應較強的部位

and here's what I saw.

於是 我找到了 這裡

Now, this image looks just awful by today's standards,

以今日的科技水準來看 這圖很糟

but at the time I thought it was beautiful.

但當時 我覺得它很美

What it shows is that region right there, that little blob,

就在那個區域 就是那個小點

it's about the size of an olive

大概只有一顆橄欖大

and it's on the bottom surface of my brain about an inch straight in from right there.

在腦部表面下緣 離這邊只有一英吋

And what that part of my brain is doing is producing a higher MRI response,

核磁共振顯示我大腦的這個部位反應較大

that is, higher neural activity, when I was looking at faces

也就是 我看著臉部時 這裡有較強烈的神經活動

than when I was looking at objects.

比看物品時反應來得強

So that's pretty cool.

這很酷吧

But how do we know this isn't a fluke?

但我們怎麼知道這不是巧合?

Well, the easiest way is to just do the experiment again.

最簡單的方法就是 再做一次實驗

So I got back in the scanner, I looked at more faces and I looked at more objects

所以我回到掃描儀中 看更多的臉部和物品

and I got a similar blob.

結果依然一樣

And then I did it again,

我又再做一次掃描

I did it again and again and again,

做了一遍一遍又一遍

and around about then I decided to believe it was for real.

之後 我決定相信結果是正確的

But still, maybe this is something weird about my brain

但這還是有可能是我大腦的特殊反應

and no one else has one of these things in there.

其他人不一定跟我一樣

So to find out, we scanned a bunch of other people and found that

所以我們找了其他受試者做實驗

pretty much everyone has that little face-processing region

發現 幾乎每個人腦都有著這個臉部辨識的小區域

in a similar neighbourhood of the brain.

都在差不多的位置

So the next question was, what does this thing really do?

下個問題是 這個區域實際的工作究竟是什麼

Is it really specialized just for face recognition?

真的是專門用來辨識人臉?

Well, maybe not, right?

其實不一定 對吧?

Maybe it responds not only to faces but to any body part.

也許對其他人體部位也有反應

Maybe it responds to anything human or anything alive or anything round.

也許對任何有關人類 生物 或是圓的東西都有反應

The only way to be really sure that that region is specialized for face recognition

唯一能確定這部位是專屬臉部辨識的方法只有

is to rule out all those hypotheses.

排除其他所有的假設

So we spent much of the next couple of years

我們花了好幾年

scanning subjects while they looked at lots of different kinds of images,

讓受試者看各式各樣的圖片 做腦部掃描

and we showed that that part of the brain responds strongly when you look at any images that are faces of any kind,

發現這部位在看任何臉部圖片時 都有強烈反應

and it responds much less strongly to any image you show that isn't a face, like some of these.

看其它不是臉的圖片時 則反應較弱 就像這樣

So have we finally nailed the case that this region is necessary for face recognition?

我們最後有斷言 辨識臉部時 一定會用到這個區域嗎?

No, we haven't.

不 我們沒有

Brain imaging can never tell you if a region is necessary for anything.

腦部顯影技術永遠無法斷定某功能是否必須用到某區域

All you can do with brain imaging is watch regions turn on and off as people think different thoughts.

只能偵測腦內不同區域在思考時的活動變化

To tell if a part of the brain is necessary for a mental function,

要確認特定部位的運作對某項心理活動是否必要

you need to mess with it and see what happens,

需要讓那個部位產生混亂 觀察後續發展

and normally we don't get to do that.

我們一般不會這麼做

But an amazing opportunity came about

但 一個神奇的機會出現了

very recently when a couple of colleagues of mine tested this man who has epilepsy

就在最近 我的兩名同事正對一位癲癇患者進行實驗

and who is shown here in this hospital bed

就是這位病床上的先生

where he's just had electrodes placed on the surface of his brain

他大腦表面正好有放置電極

to identify the source of his seizures.

用來辨識他抓住的東西

So it turned out by total chance that

完全出於巧合的是

two of the electrodes happen to be right on top of this face area.

有兩個電極 剛好就安置在這個區域的上方

So with the patient's consent,

徵求病患同意之後

the doctors asked him what happened when they electrically stimulated that part of his brain.

醫生用電流刺激大腦的臉部辨識部位 問他有何感覺

Now, the patient doesn't know where those electrodes are,

病人不知道那些電極放在哪裡

and he's never heard of the face area.

也從沒聽過臉部辨識部位

So let's watch what happens.

來看看發生了什麼是

It's going to start with a control condition that will say “Sham”

一開始會有個叫Sham的控制情境

nearly invisibly in red in the lower left,

在左下方 紅色的 幾乎看不見

when no current is delivered,

現在還沒研究公布

and you'll hear the neurologist speaking to the patient first. So let's watch.

一開始 你會聽到神經學家對病人說話 來看看吧

Okay, just look at my face and tell me what happens when I do this. Alright?

好 看著我的臉 在我這樣做時 告訴我發生甚麼事 好嗎

One, two three.

一 二 三

Nothing. –Nothing?

什麼都沒有 -什麼都沒有?

Okay, I'm going to do it one more time.

好 我再做一次

Look at my face

看著我的臉

One, two, three.

一 二 三

You just turned into somebody else.

你變成另外一個人

Your face metamorphosed.

你的臉變形了

Your nose got saggy. It went to the left.

鼻子下垂 偏到左邊去

You almost looked like somebody I'd seen before, but somebody different.

看起來好像我之前見過的某個人 但又不一樣

That was a trip.

這真是瘋了

So this experiment…

所以 這個實驗

This experiment finally nails the case

這實驗終於能夠斷定

that this region of the brain is not only selectively responsive to faces,

大腦的這個區域 不但是選擇性地對臉部有反應

but causally involved in face perception.

偶爾也會與臉部辨識有關

that this region of the brain is not only selectively responsive to faces,

我把臉部辨識區域的細節都說完了 讓你們了解

to really establish that a part of the brain is selectively involved in a specific mental process.

大腦特定部位選擇性參與特定心理活動的理論如何建立

Next, I'll go through much more quickly some of the other specialized regions of the brain that we and others have found.

接下來 我要快速分享科學家發現的腦部特定區域的功能

So to do this, I've spent a lot of time in the scanner over the last month

為了這個 上個月 我長期待在掃描儀中

so I can show you these things in my brain.

所以各位才能看見我腦中的這些東西

So let's get started.

我們開始吧

Here's my right hemisphere. So we're oriented like that.

這是我的左腦 我們腦部都長這樣

You're looking at my head this way. Imagine taking the skull off and looking at the surface of the brain like that.

從這個角度看 想像把頭蓋骨拿開 大腦表面就長這樣

Okay, now as you can see, the surface of the brain is all folded up.

好 如你所見 大腦表層充滿皺褶

So that's not good. Stuff could be hidden in there. We want to see the whole thing.

這樣不方便 皺褶可能會阻礙視野 我們想看到全貌

So let's inflate it so we can see the whole thing.

來把它攤平 這樣就能看清楚了

Next, let's find that face area I've been talking about that responds to images like these.

接下來 找出之前說的腦部辨識部位

To see that, let's turn the brain around and look on the inside surface on the bottom,

把它轉過來 看腦部表面的內側下緣

and there it is, that's my face area.

我的臉部辨識區域就在這裡

Just to the right of that is another region that is shown in purple

在它右邊的紫色區塊

that responds when you process color information.

是處理色彩資訊的區域

And near those regions are other regions that are involved in perceiving places,

這兩個區域附近 還有個處理地理資訊的區域

like right now I'm seeing this layout of space around me,

像現在 我看著這個講堂的場地配置

and these regions in green right there are really active.

這些綠色區域就會開始活躍

There's another one out on the outside surface again

外側這裡還有另一個區域

where there's a couple more face regions as well.

是另一個臉部辨識區域

Also in this vicinity is a region that's selectively involved in processing visual motion,

在這附近 還有個區域與動態處理有關

like these moving dots here,

像是處理上方那這些動點

and that's in yellow at the bottom of the brain.

動態區域就位於下方的黃色區域

And near that is a region that responds when you look at images of bodies and body parts like these,

在這旁邊 有個區域 在看到人體部位時會有反應

and that region is shown in lime green at the bottom of the brain.

也就是下方的亮綠色區域

Now all these regions I've shown you so far

到目前為止我給你們看的這些區域

are involved in specific aspects of visual perception.

都與視覺處理的特定面向有關

Do we also have specialized brain regions for other senses, like hearing?

那我們的大腦是否也有專門處理聽覺等感官的區域呢?

Yes, we do. So if we turn the brain around a little bit,

沒錯 我們再把這大腦轉過去一點

here's a region in dark blue that we recorded just a couple of months ago,

我們幾個月前 才剛發現這個深藍色區域

and this region responds strongly when you hear sounds with pitch, like these.

聽見高低音明顯的聲音時 這裡會有強烈反應 像這樣

Okay? In contrast, that same region does not respond strongly when you hear perfectly familiar sounds that don't have a clear pitch, like these.

相反的 聽見一些普通沒高低變化的聲音時 則沒啥反應

Next to the pitch region is another set of regions that are selectively responsive when you hear the sounds of speech.

音調區域旁邊的則是處理說話聲音的區域

Okay, now let's look at these same regions.

好 現在來瞧瞧這些相同的區域

In my left hemisphere, there's a similar arrangement, not identical, but similar,

在我的左腦 也有相似的區域分佈 但沒有完全一致

and most of the same regions are in here,

相同的區域大部分都在這邊

albeit sometimes different in size.

但有時大小會不太一樣

Now, everything I've shown you so far

到目前為止我介紹的一切

are regions that are involved in different aspects of perception, vision and hearing.

都是大腦處理視力 聽覺等各種感官知覺的區域

Do we also have specialized brain regions for really fancy, complicated mental processes?

那大腦是否也有特定區域來處理其他更複雜的思考過程?

Yes, we do. So here in pink are my language regions.

沒錯 真的有 粉紅色區域就是我大腦的語言區塊

So it's been known for a very long time that that general vicinity of the brain is involved in processing language.

長久以來 科學家便知道語言區域是在這一帶

But we showed very recently that these pink regions respond extremely selectively.

但最近我們發現 這幾個粉色區域對語言反應特別強烈

They respond when you understand the meaning of a sentence,

像是在理解句意時 反應便特別活躍

but not when you do other complex mental things

做其他複雜的心理活動時 則較無反應

like mental arithmetic or holding information in memory

複雜活動如進行心算 默記資訊

or appreciating the complex structure in a piece of music.

或是欣賞一段音樂的複雜結構時

The most amazing region that's been found yet is this one right here in turquoise.

目前為止 最神奇的發現是這塊藍綠色區域

This region responds when you think about what another person is thinking.

在你揣測他人心思時 這區域特別有反應

So that may seem crazy, but actually we humans do this all the time.

也許很荒唐 但其實 我們一天到晚都在揣測他人

You're doing this when you realize that your partner is going to be worried if you don't call home to say you're running late.

比方說你覺得 該打給老婆 說今天會晚回家 不然她會擔心

I'm doing this with that region of my brain right now

像現在 我就正用到這個區域

when I realize that you guys are probably now wondering about all that gray, uncharted territory in the brain, what's up with that?

因為我在想 你們會好奇 那些灰色沒標記的區域 有什麼用

Well, I'm wondering about that too,

嗯 我也很好奇