Well, as Chris pointed out, I study the human brain, the functions and structure of the human brain. And I just want you to think for a minute about what this entails. Here is this mass of jelly, three-pound mass of jelly you can hold in the palm of your hand, and it can contemplate the vastness of interstellar space. It can contemplate the meaning of infinity and it can contemplate itself contemplating on the meaning of infinity. And this peculiar recursive quality that we call self-awareness, which I think is the holy grail of neuroscience, of neurology, and hopefully, someday, we'll understand how that happens.
是的,就如克里斯的介紹,我研究人類的腦 人類大腦的功能和結構。 請大家試想一下,這牽涉到什麼? 人腦像一團三磅重的果凍, 它可以放在手掌裡, 它能思索浩瀚的星際空間, 能思索『無限』的含義, 甚至能思索自身思索『無限』含義的這件事。 這種獨特的遞迴自省特質,稱為自我意識。 我認為這是神經科學和神經病學的終極目標和意義, 希望有朝一日,我們能夠解開這個謎題。
OK, so how do you study this mysterious organ? I mean, you have 100 billion nerve cells, little wisps of protoplasm, interacting with each other, and from this activity emerges the whole spectrum of abilities that we call human nature and human consciousness. How does this happen? Well, there are many ways of approaching the functions of the human brain. One approach, the one we use mainly, is to look at patients with sustained damage to a small region of the brain, where there's been a genetic change in a small region of the brain. What then happens is not an across-the-board reduction in all your mental capacities, a sort of blunting of your cognitive ability. What you get is a highly selective loss of one function, with other functions being preserved intact, and this gives you some confidence in asserting that that part of the brain is somehow involved in mediating that function. So you can then map function onto structure, and then find out what the circuitry's doing to generate that particular function. So that's what we're trying to do.
那麼,我們要如何研究這個神秘的器官呢? 人腦有1000億個神經元細胞, 每個都是一小束原生質,彼此交互作用, 從這些活動中,產生出多不勝數的能力 即所謂人性和人的意識。 這是怎麼產生的呢? 研究人腦功能的方法很多, 其中,最常採用的方法 是觀察大腦中,一小部分區域遭受持續性損傷的病人, 研究已經發生某種基因改變的這一小部分腦區, 這並不是全面性喪失 所有的心智能力, 而是認知能力變得遲鈍, 這是一種特定功能的喪失, 而其他功能則完好無損。 我們幾乎可以確定, 大腦的這個區域影響該功能, 我們便可把功能對應到結構上, 得知這部分神經迴路是如何產生 這個特定的功能, 這就是我們的目標。
So let me give you a few striking examples of this. In fact, I'm giving you three examples, six minutes each, during this talk. The first example is an extraordinary syndrome called Capgras syndrome. If you look at the first slide there, that's the temporal lobes, frontal lobes, parietal lobes, OK -- the lobes that constitute the brain. And if you look, tucked away inside the inner surface of the temporal lobes -- you can't see it there -- is a little structure called the fusiform gyrus. And that's been called the face area in the brain, because when it's damaged, you can no longer recognize people's faces. You can still recognize them from their voice and say, "Oh yeah, that's Joe," but you can't look at their face and know who it is, right? You can't even recognize yourself in the mirror. I mean, you know it's you because you wink and it winks, and you know it's a mirror, but you don't really recognize yourself as yourself.
讓我向大家說明幾個驚人的例子, 我要提出3個例子,每段說明6分鐘, 首先,是一種非常奇特的『凱卜葛拉斯症候群』(Capgras Syndrome)。 在第一張幻燈片裡 顯示的是顳葉(temporal lobes)、額葉(frontal lobes)和頂葉(parietal lobes) 這些是構成大腦的腦葉 仔細看,你會發現顳葉的皮層內部 (這張圖裡看不出來) 是一種稱為梭狀回(fusiform gyrus)的微小結構 它被稱為腦的『臉部區域』 如果這個區域損傷,你就會喪失辨識別面孔的能力 你還是可以從聲音辨識其人 例如,你會說:『對,這個人是喬』 但你卻無法看著別人的臉認出這是誰 你甚至認不出鏡中的自己 你對鏡中人眨眼,那人也會對你眨眼 而且你知道那是一面鏡子 可是卻認不出那個人就是你自己
OK. Now that syndrome is well known as caused by damage to the fusiform gyrus. But there's another rare syndrome, so rare, in fact, that very few physicians have heard about it, not even neurologists. This is called the Capgras delusion, and that is a patient, who's otherwise completely normal, has had a head injury, comes out of coma, otherwise completely normal, he looks at his mother and says, "This looks exactly like my mother, this woman, but she's an impostor. She's some other woman pretending to be my mother." Now, why does this happen? Why would somebody -- and this person is perfectly lucid and intelligent in all other respects, but when he sees his mother, his delusion kicks in and says, it's not mother.
我們已知這種症候群是由於梭狀回損傷所導致 但還有一種非常罕見的症候群 連許多醫生、甚至神經科醫生都未曾聽聞, 叫做『凱卜葛拉斯妄想症』(Capgras Delusion) 一個原本腦部功能正常的人 頭部受到損傷,從昏迷中醒來以後, 其他腦部功能都很正常,但是他看到自己的母親 卻說:『這人看上去跟我母親一模一樣, 但她是個冒牌貨, 是個假扮我母親的女人。』 為什麼會這樣呢? 為什麼這個人理智、且完全清醒 其他各腦部功能均完好,但是看到自己的母親, 卻產生錯覺,認為不是他的母親呢?
Now, the most common interpretation of this, which you find in all the psychiatry textbooks, is a Freudian view, and that is that this chap -- and the same argument applies to women, by the way, but I'll just talk about guys. When you're a little baby, a young baby, you had a strong sexual attraction to your mother. This is the so-called Oedipus complex of Freud. I'm not saying I believe this, but this is the standard Freudian view. And then, as you grow up, the cortex develops, and inhibits these latent sexual urges towards your mother. Thank God, or you would all be sexually aroused when you saw your mother. And then what happens is, there's a blow to your head, damaging the cortex, allowing these latent sexual urges to emerge, flaming to the surface, and suddenly and inexplicably you find yourself being sexually aroused by your mother. And you say, "My God, if this is my mom, how come I'm being sexually turned on? She's some other woman. She's an impostor." It's the only interpretation that makes sense to your damaged brain.
目前最常見的解釋 所有精神病學教科書的見解 是佛洛伊德式的觀點:當這個男子 (其實女性也有同樣的情形) (但我就以男性為例討論) (佛洛伊德認為) 男性在嬰兒時期 對母親有強烈的性吸引力 即佛洛伊德所謂的『伊底帕斯』(Oedipus)戀母情結 我並不支持這種論點 但這是典型的佛洛伊德觀點。 隨著成長,腦皮層逐漸生長發育 抑制了對母親的潛在性慾。 謝天謝地,否則你每次看到你母親就會性慾高漲。 但是,當頭部受傷, 頭部的打擊損傷了腦皮層, 釋放了潛在的性衝動 浮現到最表層,突然間,莫名其妙地 你感覺到自己對母親產生了性慾 於是你想:『天啊,如果這是我媽, 我怎麼可能會有性衝動? 她一定是別的女人,是個冒牌貨。』 你受傷的大腦認為,只有這樣解釋才合理。
This has never made much sense to me, this argument. It's very ingenious, as all Freudian arguments are -- (Laughter) -- but didn't make much sense because I have seen the same delusion, a patient having the same delusion, about his pet poodle. (Laughter) He'll say, "Doctor, this is not Fifi. It looks exactly like Fifi, but it's some other dog." Right? Now, you try using the Freudian explanation there. (Laughter) You'll start talking about the latent bestiality in all humans, or some such thing, which is quite absurd, of course.
但我從不認同這種看法。 這個主張就像佛洛伊德所有的理論一樣,非常精闢 (笑聲) 但是卻不合理,因為我曾經目睹同樣的錯覺 發生在一名病患對他的貴賓狗身上。 (笑聲) 他說:『醫生,這不是菲菲吧,牠長的跟菲菲一模一樣, 但牠是另一條狗。』對吧? 現在請你套用佛洛伊德的理論解釋看看, (笑聲) 會認為人類有潛在的戀獸性, 或是其他類似的論點,這都是非常荒謬的。
Now, what's really going on? So, to explain this curious disorder, we look at the structure and functions of the normal visual pathways in the brain. Normally, visual signals come in, into the eyeballs, go to the visual areas in the brain. There are, in fact, 30 areas in the back of your brain concerned with just vision, and after processing all that, the message goes to a small structure called the fusiform gyrus, where you perceive faces. There are neurons there that are sensitive to faces. You can call it the face area of the brain, right? I talked about that earlier. Now, when that area's damaged, you lose the ability to see faces, right?
所以,實際情形究竟是怎麼回事呢? 要解釋這種奇怪的症狀, 我們來看看正常人腦視覺通路的結構和功能。 正常情況下,視覺訊號通過眼球, 進入腦中的視覺區域。 事實上,腦後部有30個專門負責視覺的區域。 經過這些區域處理之後,訊號會進入一個微小結構, 稱為『梭狀回』,就是感知面孔的地方, 那裡有對面孔敏感的神經元。 我們可以稱它為『大腦的面部區』, 我稍早提過。 這個區域一旦損壞,你就失去了識別面孔的能力。對吧?
But from that area, the message cascades into a structure called the amygdala in the limbic system, the emotional core of the brain, and that structure, called the amygdala, gauges the emotional significance of what you're looking at. Is it prey? Is it predator? Is it mate? Or is it something absolutely trivial, like a piece of lint, or a piece of chalk, or a -- I don't want to point to that, but -- or a shoe, or something like that? OK? Which you can completely ignore. So if the amygdala is excited, and this is something important, the messages then cascade into the autonomic nervous system. Your heart starts beating faster. You start sweating to dissipate the heat that you're going to create from muscular exertion. And that's fortunate, because we can put two electrodes on your palm and measure the change in skin resistance produced by sweating. So I can determine, when you're looking at something, whether you're excited or whether you're aroused, or not, OK? And I'll get to that in a minute.
但神經訊號還會通過那個區域, 進入大腦邊緣系統(limbic system)的杏仁核(amygdala), 這是腦的情緒核心, 而這個稱為杏仁核的結構, 會判斷你所看見的物體在情緒上的重要性。 在你眼前的,是獵物?掠食者?還是配偶? 還是完全無關緊要的東西,如衣服上的毛球, 或者一支粉筆。或是,我不想指出來了.. 或者是一只鞋子等等, 可以毫不理會的東西。 如果杏仁核變得興奮,表示這個東西對你很重要, 神經訊號就會繼續傳到自主神經系統, 你的心跳會開始加速, 你會開始出汗,排除因緊張而產生的體熱 即肌肉緊繃引起的。 這樣便於偵測,因為我們可以在你的手掌心貼上兩個電極 來測量汗液導致的皮膚電阻變化。 如此就能判斷,當你看著某樣東西, 是否感覺興奮?或是有沒有被挑起慾望。對吧? 這點待會我會進一步說明。
So my idea was, when this chap looks at an object, when he looks at his -- any object for that matter, it goes to the visual areas and, however, and it's processed in the fusiform gyrus, and you recognize it as a pea plant, or a table, or your mother, for that matter, OK? And then the message cascades into the amygdala, and then goes down the autonomic nervous system. But maybe, in this chap, that wire that goes from the amygdala to the limbic system, the emotional core of the brain, is cut by the accident. So because the fusiform is intact, the chap can still recognize his mother, and says, "Oh yeah, this looks like my mother." But because the wire is cut to the emotional centers, he says, "But how come, if it's my mother, I don't experience a warmth?" Or terror, as the case may be? Right? (Laughter) And therefore, he says, "How do I account for this inexplicable lack of emotions? This can't be my mother. It's some strange woman pretending to be my mother."
所以我認為,當這個人看著某物時, 或者任何物體,訊號傳到視覺區 傳入梭狀回處理 便可認出這是一顆豌豆、一張桌子, 或是他的母親,對吧? 接著,訊號繼續傳到杏仁核, 再傳到自主神經系統。 但是,或許這個病患腦中,從杏仁核到邊緣系統的線路 即連接大腦控制情緒核心的線路,在事故中被切斷了。 他的梭狀回完好無損, 所以還能認出他的母親, 心想:『是啊,這女人長得跟我母親一樣。』 但由於通往情緒中心的線路被截斷了, 他就會懷疑:『如果真是我母親, 為什麼我看見她卻沒有溫暖的感覺?』 或者有些人可能會產生恐懼感,嗯? (笑聲) 於是他會想:『該如何解釋我的欠缺情緒反應呢? 她不可能是我的母親。 是某個陌生女人假裝是我的母親。』
How do you test this? Well, what you do is, if you take any one of you here, and put you in front of a screen, and measure your galvanic skin response, and show pictures on the screen, I can measure how you sweat when you see an object, like a table or an umbrella. Of course, you don't sweat. If I show you a picture of a lion, or a tiger, or a pinup, you start sweating, right? And, believe it or not, if I show you a picture of your mother -- I'm talking about normal people -- you start sweating. You don't even have to be Jewish. (Laughter)
這種現象該如何驗證呢? 方法是,例如,請你們其中一位觀眾上來站在螢幕前, 我一邊測量你的皮膚電反應(GSR), 一邊在螢幕上播放圖片給你看。 我可以測量你看見各個物體時的出汗情形。 例如,看見桌子或雨傘時,你當然不至於出汗, 如果看到獅子、老虎或性感女郎,你就會冒汗了。對吧? 信不信,如果我給你看你母親的照片, 我是指一般正常人,就會開始流汗, 不一定是猶太人才有這種反應。 (譯註:猶太媽媽的刻版印象是專橫嘮叨、管教甚嚴) (笑聲)
Now, what happens if you show this patient? You take the patient and show him pictures on the screen and measure his galvanic skin response. Tables and chairs and lint, nothing happens, as in normal people, but when you show him a picture of his mother, the galvanic skin response is flat. There's no emotional reaction to his mother, because that wire going from the visual areas to the emotional centers is cut. So his vision is normal because the visual areas are normal, his emotions are normal -- he'll laugh, he'll cry, so on and so forth -- but the wire from vision to emotions is cut and therefore he has this delusion that his mother is an impostor. It's a lovely example of the sort of thing we do: take a bizarre, seemingly incomprehensible, neural psychiatric syndrome and say that the standard Freudian view is wrong, that, in fact, you can come up with a precise explanation in terms of the known neural anatomy of the brain.
同樣的實驗,對前述的病患,反應又是如何呢? 你把他帶到螢幕前,播放圖片給他看, 測量他的皮膚電反應(GSR)。 看桌子、椅子、毛球,沒有反應,跟正常人一樣; 但是當你給他看他母親的照片, 皮膚電圖像還是平的, 他對自己的母親也沒有情緒反應, 因為從視覺區通往情緒中心的線路被切斷了。 他的視覺沒有問題,因為視覺區功能正常, 他的情緒反應能力也沒有問題,他會哭會笑,等等 但是從視覺到情緒的線路卻阻斷了, 因此他會產生錯覺,認為他母親是冒牌貨。 這個有趣的例子可以說明我們從事的研究, 探究這類奇特、看似無法理解的神經精神症候群, 來證明傳統佛洛伊德觀點的謬誤, 事實上,你可以找到精確的解釋, 從已知的大腦神經解剖學找出答案。
By the way, if this patient then goes, and mother phones from an adjacent room -- phones him -- and he picks up the phone, and he says, "Wow, mom, how are you? Where are you?" There's no delusion through the phone. Then, she approaches him after an hour, he says, "Who are you? You look just like my mother." OK? The reason is there's a separate pathway going from the hearing centers in the brain to the emotional centers, and that's not been cut by the accident. So this explains why through the phone he recognizes his mother, no problem. When he sees her in person, he says it's an impostor.
順帶一提,如果這個病人離開, 他母親從隔壁打電話來, 他會接起電話說:『哇,媽,妳好不好?妳在哪裡?』 透過電話,不會產生錯覺。 一小時後,當母親走到他面前,他又會問:『妳是誰呀? 妳長得跟我母親一模一樣!』 原因是,有另一條通路 從腦的聽覺中心通往情緒中心, 這條通路並沒有被事故切斷。 這是為什麼他能透過電話認出母親,毫無問題; 但是當他看到母親本人,卻說她是假冒者。
OK, how is all this complex circuitry set up in the brain? Is it nature, genes, or is it nurture? And we approach this problem by considering another curious syndrome called phantom limb. And you all know what a phantom limb is. When an arm is amputated, or a leg is amputated, for gangrene, or you lose it in war -- for example, in the Iraq war, it's now a serious problem -- you continue to vividly feel the presence of that missing arm, and that's called a phantom arm or a phantom leg. In fact, you can get a phantom with almost any part of the body. Believe it or not, even with internal viscera. I've had patients with the uterus removed -- hysterectomy -- who have a phantom uterus, including phantom menstrual cramps at the appropriate time of the month. And in fact, one student asked me the other day, "Do they get phantom PMS?" (Laughter) A subject ripe for scientific enquiry, but we haven't pursued that.
大腦究竟是如何建構發展出如此複雜的迴路呢? 是先天、基因、還是後天的作用? 要解開這個謎題, 可透過研究另一種奇特的症候群,稱為『幻肢』。 各位都知道幻肢是什麼 當一條手臂或腿因為壞疽被切除, 或在戰爭(如伊拉克戰爭)中失去, 我們發現這會產生嚴重的問題 傷者仍能強烈地感受到那條已經失去的手臂的存在, 這就是所謂的幻臂(phantom arm)或幻腿(phantom leg)。 事實上,身體任何部位都有可能產生這種幻肢現象, 甚至連內臟器官都有可能。 我有位病人,做子宮切除術除去了子宮, 她得了幻子宮症,還會有幻經痛 每個月都會定期感到經痛。 甚至,前幾天還有學生問我, 她們有沒有幻經前症候群? (笑聲) 這頗值得科學研究,但我們還沒有探討過。
OK, now the next question is, what can you learn about phantom limbs by doing experiments? One of the things we've found was, about half the patients with phantom limbs claim that they can move the phantom. It'll pat his brother on the shoulder, it'll answer the phone when it rings, it'll wave goodbye. These are very compelling, vivid sensations. The patient's not delusional. He knows that the arm is not there, but, nevertheless, it's a compelling sensory experience for the patient. But however, about half the patients, this doesn't happen. The phantom limb -- they'll say, "But doctor, the phantom limb is paralyzed. It's fixed in a clenched spasm and it's excruciatingly painful. If only I could move it, maybe the pain will be relieved."
好了,接下來的問題是: 我們能透過實驗,對幻肢現象獲得什麼了解? 我們發現, 半數的幻肢病患, 宣稱自己可以移動那條幻肢。 能用幻肢拍兄弟的肩膀, 能在電話鈴響時拿起聽筒,還能揮手道別。 這些感覺真實而強烈, 病患並不是在妄想。 他們明知道手臂已經不在了, 但感覺還是非常強烈。 不過,另一半病患倒是沒有這種現象。 病患會說:『醫生,我的幻肢麻痺了, 緊繃痙攣,無法動彈,劇烈疼痛。 如果我能移動它,疼痛或許會減輕。
Now, why would a phantom limb be paralyzed? It sounds like an oxymoron. But when we were looking at the case sheets, what we found was, these people with the paralyzed phantom limbs, the original arm was paralyzed because of the peripheral nerve injury. The actual nerve supplying the arm was severed, was cut, by say, a motorcycle accident. So the patient had an actual arm, which is painful, in a sling for a few months or a year, and then, in a misguided attempt to get rid of the pain in the arm, the surgeon amputates the arm, and then you get a phantom arm with the same pains, right? And this is a serious clinical problem. Patients become depressed. Some of them are driven to suicide, OK?
奇怪的是,既然是幻肢,為什麼會麻痺癱瘓呢? 這不是自相矛盾嗎? 我們研究病歷表發現, 這些感覺幻肢癱瘓的病患, 手臂還在時,曾經因為周圍神經受傷而癱瘓, 控制手臂的神經被切斷, 例如,若病患因機車事故,切斷實際的手臂神經, 他(尚未切除)的手臂會感到疼痛, 吊著繃帶好幾個月或一整年。後來, 為了消除疼痛,判斷失當, 被外科醫師做了截肢手術, 結果形成幻臂,而且疼痛還是存在。 這是非常嚴重的臨床問題。 病患變得憂鬱沮喪, 有些人甚至因而自殺。
So, how do you treat this syndrome? Now, why do you get a paralyzed phantom limb? When I looked at the case sheet, I found that they had an actual arm, and the nerves supplying the arm had been cut, and the actual arm had been paralyzed, and lying in a sling for several months before the amputation, and this pain then gets carried over into the phantom itself.
那麼,這種症候群該如何治療呢? 首先要問的是,為什麼有人會覺得幻肢麻痺? 我研究病歷,發現他們的手臂還確實存在時, 控制該手臂的神經被切斷, 導致該手臂麻痺, 吊在繃帶裡,癱瘓了好幾個月,才被截肢。 截肢前的疼痛,卻持續延伸到幻臂裡。
Why does this happen? When the arm was intact, but paralyzed, the brain sends commands to the arm, the front of the brain, saying, "Move," but it's getting visual feedback saying, "No." Move. No. Move. No. Move. No. And this gets wired into the circuitry of the brain, and we call this learned paralysis, OK? The brain learns, because of this Hebbian, associative link, that the mere command to move the arm creates a sensation of a paralyzed arm. And then, when you've amputated the arm, this learned paralysis carries over into your body image and into your phantom, OK?
為什麼會這樣呢? 當手臂尚未切除,但麻痺時, 前腦發送指令給手臂,命令它:『移動!』 但視覺卻回應大腦說:『動不了。』 『動!』『動不了。』『動!』『動不了。』... 這個反覆模式被固著在大腦的神經迴路中, 這叫做『習得性癱瘓』(learned paralysis)。 大腦以為,因為這種海伯聯結(Hebbian associative link) 使這個移動手臂的簡單指令, 導致麻痺手臂的疼痛感。 截除手臂以後, 這種『習得性癱瘓』蔓延到你的身體意象(body image), 深入幻肢之中。
Now, how do you help these patients? How do you unlearn the learned paralysis, so you can relieve him of this excruciating, clenching spasm of the phantom arm? Well, we said, what if you now send the command to the phantom, but give him visual feedback that it's obeying his command, right? Maybe you can relieve the phantom pain, the phantom cramp. How do you do that? Well, virtual reality. But that costs millions of dollars. So, I hit on a way of doing this for three dollars, but don't tell my funding agencies. (Laughter)
那麼,該怎麼幫助這些病患呢? 怎樣拋卻已習得的癱瘓, 解除病患幻臂中劇痛的痙攣? . 於是我們想,要是讓大腦對幻肢發送命令, 並讓視覺回應告知大腦,幻肢服從命令,如何? 或許就會消除幻肢疼痛和痙攣了。 要怎樣做呢?用虛擬實境(virtual reality)吧? 但那要花好幾百萬。 我想到一個辦法,只要花3美元, 不要告訴我的贊助機構。 (笑聲)
OK? What you do is you create what I call a mirror box. You have a cardboard box with a mirror in the middle, and then you put the phantom -- so my first patient, Derek, came in. He had his arm amputated 10 years ago. He had a brachial avulsion, so the nerves were cut and the arm was paralyzed, lying in a sling for a year, and then the arm was amputated. He had a phantom arm, excruciatingly painful, and he couldn't move it. It was a paralyzed phantom arm.
首先,要做一個『鏡盒』, 在紙板盒中間放一面鏡子, 然後放置幻肢。我的第一個病患,德瑞克進來, 他在10年前截除手臂。 之前曾經受了臂神經叢撕脫傷(brachial avulsion),神經被切斷, 手臂從此癱瘓,掛著繃帶一年後,接受截肢手術。 接著產生幻肢,疼痛難當,而且無法自由移動。 他這就是『習得性癱瘓』的手臂。
So he came there, and I gave him a mirror like that, in a box, which I call a mirror box, right? And the patient puts his phantom left arm, which is clenched and in spasm, on the left side of the mirror, and the normal hand on the right side of the mirror, and makes the same posture, the clenched posture, and looks inside the mirror. And what does he experience? He looks at the phantom being resurrected, because he's looking at the reflection of the normal arm in the mirror, and it looks like this phantom has been resurrected. "Now," I said, "now, look, wiggle your phantom -- your real fingers, or move your real fingers while looking in the mirror." He's going to get the visual impression that the phantom is moving, right? That's obvious, but the astonishing thing is, the patient then says, "Oh my God, my phantom is moving again, and the pain, the clenching spasm, is relieved."
他來看病時,我給他一面像這樣的鏡子,在盒子裡 我稱為鏡盒,對吧? 我把病患的幻肢左臂 (繃緊痙攣的那隻) 放在鏡子左邊, 正常的手臂放在鏡子右邊, 並模仿左臂的姿勢,握緊的姿勢, 然後看著鏡子,你猜他感覺到了什麼? 他感覺幻肢又復活了。 因為他看到了鏡中正常手臂的反射鏡像, 彷彿他的幻肢重生了。 然後我說:『現在,擺動一下你的幻臂, (更正)你真正的手指;一面看著鏡子,一面擺動你(左手)真正的手指。』 他的視覺印象會告訴他,幻肢正在擺動,對吧? 這是顯而易見的。但令人驚訝的是, 病患叫說:『天啊,我的幻臂居然可以移動了, 而且那繃緊痙攣的疼痛不見啦!』
And remember, my first patient who came in -- (Applause) -- thank you. (Applause) My first patient came in, and he looked in the mirror, and I said, "Look at your reflection of your phantom." And he started giggling, he says, "I can see my phantom." But he's not stupid. He knows it's not real. He knows it's a mirror reflection, but it's a vivid sensory experience. Now, I said, "Move your normal hand and phantom." He said, "Oh, I can't move my phantom. You know that. It's painful." I said, "Move your normal hand." And he says, "Oh my God, my phantom is moving again. I don't believe this! And my pain is being relieved." OK? And then I said, "Close your eyes." He closes his eyes. "And move your normal hand." "Oh, nothing. It's clenched again." "OK, open your eyes." "Oh my God, oh my God, it's moving again!" So, he was like a kid in a candy store.
記得嗎?我的首位病患進來—— (掌聲) 謝謝(掌聲) 我的第一個病患來看病時,他看著鏡子, 我說:『看著你幻肢的鏡像。』 他咯咯笑起來,說:『我看得見我的幻肢。』 他並不笨,知道這不是真實的, 他知道那只是個鏡像, 但這卻是非常逼真的體驗。 然後我說:『移動你正常的手臂,和幻臂』。 他說:『我沒辦法移動我的幻臂,你知道,很痛啊!』 我說:『那就移動正常的那隻手吧。 』 他說:『天啊,我的幻臂又在動了,簡直不敢相信! 手也不痛了! 』 接著我說:『閉上眼睛。』 他閉上眼。 我說:『動一下你正常的那隻手。』 他說:『喔,動不了,又繃緊麻痺了。』 我說:『睜開眼睛。』 他說:『天啊,又在動了!』 他興奮地像個糖果店裡的孩子。
So, I said, OK, this proves my theory about learned paralysis and the critical role of visual input, but I'm not going to get a Nobel Prize for getting somebody to move his phantom limb. (Laughter) (Applause) It's a completely useless ability, if you think about it. (Laughter) But then I started realizing, maybe other kinds of paralysis that you see in neurology, like stroke, focal dystonias -- there may be a learned component to this, which you can overcome with the simple device of using a mirror.
所以我說,這證明了我的習得性麻痺理論, 和視覺輸入的關鍵性。 但是諾貝爾獎不會頒給我 只因為我能讓人移動幻肢。 (笑聲) (掌聲) 仔細想想,這還真是毫無用處的能力哩! (笑聲) 但是後來我開始意識到,也許其他類型的癱瘓, 神經病學中的癱瘓,例如中風、局部肌張力不全症(focal dystonia), 或許都有習得的成分, 都能藉助這種鏡盒來克服。
So, I said, "Look, Derek" -- well, first of all, the guy can't just go around carrying a mirror to alleviate his pain -- I said, "Look, Derek, take it home and practice with it for a week or two. Maybe, after a period of practice, you can dispense with the mirror, unlearn the paralysis, and start moving your paralyzed arm, and then, relieve yourself of pain." So he said OK, and he took it home. I said, "Look, it's, after all, two dollars. Take it home."
於是我說:『德瑞克,』 病患總不能一直隨身帶著鏡盒,來減輕痛苦吧? 我說:『德瑞克,鏡盒讓你帶回家,自己練習一兩個禮拜, 或許反覆練習一段時間, 你就可以扔掉鏡子,擺脫癱瘓, 自由移動幻肢, 跟疼痛說再見啦!』 他說好啊,就帶著鏡盒回家了。 我說:『反正只花我2塊錢而已,你就帶回家吧。』
So, he took it home, and after two weeks, he phones me, and he said, "Doctor, you're not going to believe this." I said, "What?" He said, "It's gone." I said, "What's gone?" I thought maybe the mirror box was gone. (Laughter) He said, "No, no, no, you know this phantom I've had for the last 10 years? It's disappeared." And I said -- I got worried, I said, my God, I mean I've changed this guy's body image, what about human subjects, ethics and all of that? And I said, "Derek, does this bother you?" He said, "No, last three days, I've not had a phantom arm and therefore no phantom elbow pain, no clenching, no phantom forearm pain, all those pains are gone away. But the problem is I still have my phantom fingers dangling from the shoulder, and your box doesn't reach." (Laughter) "So, can you change the design and put it on my forehead, so I can, you know, do this and eliminate my phantom fingers?" He thought I was some kind of magician.
於是他把鏡盒帶回家。兩週後他打來電話來, 說:『醫生,你一定不相信。』 我說:『不相信什麼?』 他說:『它不見了。』 我說:『什麼不見了?』 我還以為可能是鏡盒不見了。 (笑聲) 他說:『不不不,這個困擾了我10年的幻臂, 它不見啦! 』 我有點擔心,我說,天哪! 我改變了他的身體形像, 但是有關人體主體、倫理道德等等議題呢? 我說:『德瑞克,你覺得困擾嗎?』 他說:『不會呀!這三天來,我的幻臂消失了, 幻肘關節痛也沒了,也不再肌肉緊繃, 幻肢上臂疼痛也沒了,所有疼痛都消失了! 不過問題是,我的幻手指還接在肩膀上, 你的鏡盒搆不到耶!』 (笑聲) 『你能不能改一下設計,把鏡盒放在我的前額, 讓我練習消除我的幻手指? 』 他以為我會變魔術呢!
Now, why does this happen? It's because the brain is faced with tremendous sensory conflict. It's getting messages from vision saying the phantom is back. On the other hand, there's no proprioception, muscle signals saying that there is no arm, right? And your motor command saying there is an arm, and, because of this conflict, the brain says, to hell with it, there is no phantom, there is no arm, right? It goes into a sort of denial -- it gates the signals. And when the arm disappears, the bonus is, the pain disappears because you can't have disembodied pain floating out there, in space. So, that's the bonus.
為什麼會發生這種現象呢? 這是因為大腦受到極大的知覺衝突, 它收到視覺訊號,說幻肢長回來了; 但另一方面,卻沒有接收到實際的相應訊號, 來自肌肉的訊號說手臂不存在,不是嗎? 可是運動神經指令也在說手臂存在。 由於這種衝突,大腦乾脆說:『管他的, 根本沒有幻肢、沒有手臂啦!』 大腦陷入某種否認狀態,否認這些訊號。 當幻臂消失時,好處是疼痛也一併消失, 因為總不可能有無形體疼痛在空中漂浮吧? 所以這是它的好處。
Now, this technique has been tried on dozens of patients by other groups in Helsinki, so it may prove to be valuable as a treatment for phantom pain, and indeed, people have tried it for stroke rehabilitation. Stroke you normally think of as damage to the fibers, nothing you can do about it. But, it turns out some component of stroke paralysis is also learned paralysis, and maybe that component can be overcome using mirrors. This has also gone through clinical trials, helping lots and lots of patients.
這種療法已經在幾十個病患身上試驗過, 由赫爾辛基的其他醫療團體, 以證實它有助於治療幻肢疼痛。 的確,它已被試用於中風復健。 一般認為,中風是神經纖維受損, 無方可治。 但是我們發現,其實中風癱瘓也含有習得的成分, 或許這種鏡療法可以用來療癒其習得成分。 這也已經臨床試驗, 幫助過許多病患。
OK, let me switch gears now to the third part of my talk, which is about another curious phenomenon called synesthesia. This was discovered by Francis Galton in the nineteenth century. He was a cousin of Charles Darwin. He pointed out that certain people in the population, who are otherwise completely normal, had the following peculiarity: every time they see a number, it's colored. Five is blue, seven is yellow, eight is chartreuse, nine is indigo, OK? Bear in mind, these people are completely normal in other respects. Or C sharp -- sometimes, tones evoke color. C sharp is blue, F sharp is green, another tone might be yellow, right?
接下來是我要講的第三部分, 是關於另一種奇特的現象,叫做『聯覺』(Synesthesia)。 由弗朗西斯.高爾頓在十九世紀所發現。 他是達爾文的表親。 他發現有些人, 其他方面均無異於常人,卻有如下奇特之處—— 他們看到一個數字時,就能感受到色彩。 5是藍色;7是黃色;8是黃綠色; 9是紫藍色。 記住,這些人其他方面完全正常。 有時,音調也能喚起色彩, 升C是藍色,升F是綠色, 其他音調可能是黃色等等。
Why does this happen? This is called synesthesia. Galton called it synesthesia, a mingling of the senses. In us, all the senses are distinct. These people muddle up their senses. Why does this happen? One of the two aspects of this problem are very intriguing. Synesthesia runs in families, so Galton said this is a hereditary basis, a genetic basis. Secondly, synesthesia is about -- and this is what gets me to my point about the main theme of this lecture, which is about creativity -- synesthesia is eight times more common among artists, poets, novelists and other creative people than in the general population. Why would that be? I'm going to answer that question. It's never been answered before.
為什麼會這樣? 高爾頓把這稱為『聯覺』(synaesthesia), 這是一種感覺的混合。 對我們一般人來說,感覺是各自獨立的, 這些人的多種感覺卻會混合。 為什麼會這樣? 這種現象有兩個有趣之處, 聯覺有家族遺傳, 因此高爾頓認為這跟遺傳基因有關。 其次,『聯覺』與某特質有關——(這就是我要傳達的重點) 就是這個演講的主題:創造力—— 『聯覺』在藝術家、詩人、作家,以及其他創意人中更普遍, 是普通人的8倍。 為什麼會這樣? 我要回答這個問題, 這個問題之前無人解答過。
OK, what is synesthesia? What causes it? Well, there are many theories. One theory is they're just crazy. Now, that's not really a scientific theory, so we can forget about it. Another theory is they are acid junkies and potheads, right? Now, there may be some truth to this, because it's much more common here in the Bay Area than in San Diego. (Laughter) OK. Now, the third theory is that -- well, let's ask ourselves what's really going on in synesthesia. All right?
究竟什麼是『聯覺』,成因是什麼? 相關的理論很多。 一種理論認為,這些人瘋了, 這算不上科學理論,所以不多談了。 另一個理論是這些人是吸毒者,大麻癮君子。 這或許有點道理, 因為『聯覺』人口在灣區比在聖地牙哥多得多。 (笑聲) 第三個理論是, 我們要問:『聯覺』到底是怎麼產生的?
So, we found that the color area and the number area are right next to each other in the brain, in the fusiform gyrus. So we said, there's some accidental cross wiring between color and numbers in the brain. So, every time you see a number, you see a corresponding color, and that's why you get synesthesia. Now remember -- why does this happen? Why would there be crossed wires in some people? Remember I said it runs in families? That gives you the clue. And that is, there is an abnormal gene, a mutation in the gene that causes this abnormal cross wiring.
我們發現,圖中的顏色區和數字區 在大腦的梭狀回裡彼此相鄰, 因此,腦中可能發生意外的線路叉接(cross-wiring), 即顏色區與數字區之間的線路。 所以,每次看見某個數字,就會同時看見相應的顏色, 於是產生所謂的『聯覺』。 記住,為什麼會發生這種現象呢? 為什麼有些人腦中會發生線路叉接呢? 我剛說過,這是家族遺傳的, 這就提供了線索。 有某個異常的基因, 一種基因突變,引起了異常的線路叉接。
In all of us, it turns out we are born with everything wired to everything else. So, every brain region is wired to every other region, and these are trimmed down to create the characteristic modular architecture of the adult brain. So, if there's a gene causing this trimming and if that gene mutates, then you get deficient trimming between adjacent brain areas. And if it's between number and color, you get number-color synesthesia. If it's between tone and color, you get tone-color synesthesia. So far, so good.
其實,我們每個人 出生時,腦中線路彼此相連, 所有腦部區域都彼此互通, 然後逐漸修整區別, 劃分形成成人腦中,各具不同特徵的模塊。 如果有一個基因控制這種修整過程, 而它產生突變, 那麼相鄰腦區間的修整就不充分了, 若發生在數字和顏色之間,就產生『數字—顏色聯覺症』。 若發生在音調和顏色之間,就產生『音調—顏色聯覺症』。 這些解釋都合理。
Now, what if this gene is expressed everywhere in the brain, so everything is cross-connected? Well, think about what artists, novelists and poets have in common, the ability to engage in metaphorical thinking, linking seemingly unrelated ideas, such as, "It is the east, and Juliet is the Sun." Well, you don't say, Juliet is the sun, does that mean she's a glowing ball of fire? I mean, schizophrenics do that, but it's a different story, right? Normal people say, she's warm like the sun, she's radiant like the sun, she's nurturing like the sun. Instantly, you've found the links.
要是這個突變基因,在腦中的所有地方都起了作用呢? 所有的腦區都相聯的話呢? 想想看,藝術家、作家和詩人之間有什麼共通處? 他們都具備隱喻思維 (metaphorical thinking) 能力, 把看似無關的概念,加以聯結。 例如,『這是東方,茱麗葉就是太陽。』 你不會說茱麗葉是個太陽, 這話難道是指『她是團炙熱的火球』嗎? 精神分裂的人會這麼想,但那當別論。 正常人會說:『她像太陽一樣溫暖』 『她像太陽一樣明艷照人』、『她像太陽一樣撫慰心靈』 其中的聯繫顯而易見。
Now, if you assume that this greater cross wiring and concepts are also in different parts of the brain, then it's going to create a greater propensity towards metaphorical thinking and creativity in people with synesthesia. And, hence, the eight times more common incidence of synesthesia among poets, artists and novelists. OK, it's a very phrenological view of synesthesia. The last demonstration -- can I take one minute? (Applause)
現在,若假設更大規模的這種線路叉接, 以及概念,也位於腦的不同區域, 就會形成更強烈的傾向 突顯有聯覺症者的隱喻思維和創造性。 . 因此,(某類人群)聯覺症比例是常人的8倍 包括藝術家、詩人和作家等。 好,這是非常顱相學(phrenological)的聯覺理論。 最後再做個實驗——再給我一分鐘好嗎? (掌聲)
OK. I'm going to show you that you're all synesthetes, but you're in denial about it. Here's what I call Martian alphabet. Just like your alphabet, A is A, B is B, C is C. Different shapes for different phonemes, right? Here, you've got Martian alphabet. One of them is Kiki, one of them is Bouba. Which one is Kiki and which one is Bouba? How many of you think that's Kiki and that's Bouba? Raise your hands. Well, it's one or two mutants. (Laughter) How many of you think that's Bouba, that's Kiki? Raise your hands. Ninety-nine percent of you.
我要向各位展示:你們全都有聯覺症,只是自己不自知罷了。 這張圖,我稱為『火星字母表』,就像英文字母表。 A是A、B是B、C是C 不同音素對應不同的形狀,對吧? 這是『火星字母表』, 其中一個是『Kiki』,另一個是『Buba』。 請問哪一個是『Kiki』,哪一個是『Buba』呢? 有多少人覺得這邊是『Kiki』,那邊是『Buba』?請舉手。 嗯,有一、兩位突變。 (笑聲) 有多少人覺得這邊是『Buba』,那邊是『Kiki』?請舉手。 在座百分之九十九的人。
Now, none of you is a Martian. How did you do that? It's because you're all doing a cross-model synesthetic abstraction, meaning you're saying that that sharp inflection -- ki-ki, in your auditory cortex, the hair cells being excited -- Kiki, mimics the visual inflection, sudden inflection of that jagged shape. Now, this is very important, because what it's telling you is your brain is engaging in a primitive -- it's just -- it looks like a silly illusion, but these photons in your eye are doing this shape, and hair cells in your ear are exciting the auditory pattern, but the brain is able to extract the common denominator. It's a primitive form of abstraction, and we now know this happens in the fusiform gyrus of the brain, because when that's damaged, these people lose the ability to engage in Bouba Kiki, but they also lose the ability to engage in metaphor.
各位都不是火星人,你們是怎麼認出來呢? 因為各位都在進行跨模塊的『聯覺抽象』, 你覺得那尖尖的形狀看起來像『Kiki』, 在你的聽覺腦皮層中,聽毛細胞受刺激,『Kiki』 就像那個鋸齒形狀的視覺曲折,生硬而突然。 這點非常重要,因為它說明 你的大腦正在進行一種原生的程序 雖然它看起來有點可笑, 但這些光子在你眼中形成這個形狀, 同時你耳中的聽毛細胞刺激這個聽覺模式, 但是大腦能夠抽取兩者的共性。 這是一種原始形式的抽象。 我們現在知道,這發生在大腦的梭狀回, 因為那裡如果受損, 病患就無法判斷『Buba、Kiki』, 也失去隱喻的能力。
If you ask this guy, what -- "all that glitters is not gold," what does that mean?" The patient says, "Well, if it's metallic and shiny, it doesn't mean it's gold. You have to measure its specific gravity, OK?" So, they completely miss the metaphorical meaning. So, this area is about eight times the size in higher -- especially in humans -- as in lower primates. Something very interesting is going on here in the angular gyrus, because it's the crossroads between hearing, vision and touch, and it became enormous in humans. And something very interesting is going on. And I think it's a basis of many uniquely human abilities like abstraction, metaphor and creativity. All of these questions that philosophers have been studying for millennia, we scientists can begin to explore by doing brain imaging, and by studying patients and asking the right questions. Thank you. (Applause) Sorry about that. (Laughter)
若問他:『發亮的未必都是黃金』(譯註:英諺,意同『金玉其外,敗絮其中』) 這話什麼意思? 他會說:『意思是,若是金屬且發亮,不表示一定是黃金, 得測試它的比重。』 這個病患無法明白其中的比喻涵義。 這個腦區的體積,在高等靈長類 尤其是人類,是低等靈長類的8倍。 角形腦回(angular gyrus)是個很有趣的區域, 它是視覺、聽覺和觸覺的交匯處, 人類的角形腦回特別大,因此具備非常複雜的功能。 我認為它是許多人類特有能力的基礎, 例如抽象、隱喻,和創造。 這些問題,哲學家已經研究上千年了, 現在,我們科學家可以利用腦部造影, 研究病患,並提出正確的問題,加以探索。 謝謝。 (掌聲) 抱歉。 (笑聲)