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Well, as Chris pointed out, I study the human brain,

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the functions and structure of the human brain.

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And I just want you to think for a minute about what this entails.

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Here is this mass of jelly, three-pound mass of jelly

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you can hold in the palm of your hand,

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and it can contemplate the vastness of interstellar space.

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It can contemplate the meaning of infinity

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and it can contemplate itself contemplating on the meaning of infinity.

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And this peculiar recursive quality that we call self-awareness,

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which I think is the holy grail of neuroscience, of neurology,

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and hopefully, someday, we'll understand how that happens.

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OK, so how do you study this mysterious organ?

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I mean, you have 100 billion nerve cells,

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little wisps of protoplasm, interacting with each other,

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and from this activity emerges the whole spectrum of abilities

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that we call human nature and human consciousness.

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How does this happen?

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Well, there are many ways of approaching the functions of the human brain.

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One approach, the one we use mainly,

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is to look at patients with sustained damage to a small region of the brain,

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where there's been a genetic change in a small region of the brain.

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What then happens is not an across-the-board reduction

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in all your mental capacities,

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a sort of blunting of your cognitive ability.

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What you get is a highly selective loss of one function,

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with other functions being preserved intact,

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and this gives you some confidence in asserting

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that that part of the brain is somehow involved in mediating that function.

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So you can then map function onto structure,

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and then find out what the circuitry's doing

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to generate that particular function.

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So that's what we're trying to do.

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So let me give you a few striking examples of this.

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In fact, I'm giving you three examples, six minutes each, during this talk.

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The first example is an extraordinary syndrome called Capgras syndrome.

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If you look at the first slide there,

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that's the temporal lobes, frontal lobes, parietal lobes, OK --

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the lobes that constitute the brain.

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And if you look, tucked away inside the inner surface of the temporal lobes --

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you can't see it there --

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is a little structure called the fusiform gyrus.

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And that's been called the face area in the brain,

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because when it's damaged, you can no longer recognize people's faces.

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You can still recognize them from their voice

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and say, "Oh yeah, that's Joe,"

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but you can't look at their face and know who it is, right?

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You can't even recognize yourself in the mirror.

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I mean, you know it's you because you wink and it winks,

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and you know it's a mirror,

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but you don't really recognize yourself as yourself.

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OK. Now that syndrome is well known as caused by damage to the fusiform gyrus.

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But there's another rare syndrome, so rare, in fact,

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that very few physicians have heard about it, not even neurologists.

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This is called the Capgras delusion,

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and that is a patient, who's otherwise completely normal,

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has had a head injury, comes out of coma,

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otherwise completely normal, he looks at his mother

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and says, "This looks exactly like my mother, this woman,

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but she's an impostor.

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She's some other woman pretending to be my mother."

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Now, why does this happen?

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Why would somebody -- and this person is perfectly lucid and intelligent

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in all other respects, but when he sees his mother,

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his delusion kicks in and says, it's not mother.

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Now, the most common interpretation of this,

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which you find in all the psychiatry textbooks,

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is a Freudian view, and that is that this chap --

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and the same argument applies to women, by the way,

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but I'll just talk about guys.

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When you're a little baby, a young baby,

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you had a strong sexual attraction to your mother.

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This is the so-called Oedipus complex of Freud.

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I'm not saying I believe this,

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but this is the standard Freudian view.

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And then, as you grow up, the cortex develops,

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and inhibits these latent sexual urges towards your mother.

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Thank God, or you would all be sexually aroused when you saw your mother.

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And then what happens is,

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there's a blow to your head, damaging the cortex,

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allowing these latent sexual urges to emerge,

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flaming to the surface, and suddenly and inexplicably

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you find yourself being sexually aroused by your mother.

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And you say, "My God, if this is my mom,

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how come I'm being sexually turned on?

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She's some other woman. She's an impostor."

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It's the only interpretation that makes sense to your damaged brain.

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This has never made much sense to me, this argument.

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It's very ingenious, as all Freudian arguments are --

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(Laughter)

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-- but didn't make much sense because I have seen the same delusion,

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a patient having the same delusion, about his pet poodle.

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(Laughter)

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He'll say, "Doctor, this is not Fifi. It looks exactly like Fifi,

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but it's some other dog." Right?

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Now, you try using the Freudian explanation there.

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(Laughter)

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You'll start talking about the latent bestiality in all humans,

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or some such thing, which is quite absurd, of course.

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Now, what's really going on?

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So, to explain this curious disorder,

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we look at the structure and functions of the normal visual pathways in the brain.

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Normally, visual signals come in, into the eyeballs,

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go to the visual areas in the brain.

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There are, in fact, 30 areas in the back of your brain concerned with just vision,

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and after processing all that, the message goes to a small structure

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called the fusiform gyrus, where you perceive faces.

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There are neurons there that are sensitive to faces.

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You can call it the face area of the brain, right?

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I talked about that earlier.

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Now, when that area's damaged, you lose the ability to see faces, right?

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But from that area, the message cascades

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into a structure called the amygdala in the limbic system,

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the emotional core of the brain,

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and that structure, called the amygdala,

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gauges the emotional significance of what you're looking at.

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Is it prey? Is it predator? Is it mate?

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Or is it something absolutely trivial, like a piece of lint,

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or a piece of chalk, or a -- I don't want to point to that, but --

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or a shoe, or something like that? OK?

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Which you can completely ignore.

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So if the amygdala is excited, and this is something important,

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the messages then cascade into the autonomic nervous system.

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Your heart starts beating faster.

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You start sweating to dissipate the heat that you're going to

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create from muscular exertion.

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And that's fortunate, because we can put two electrodes on your palm

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and measure the change in skin resistance produced by sweating.

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So I can determine, when you're looking at something,

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whether you're excited or whether you're aroused, or not, OK?

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And I'll get to that in a minute.

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So my idea was, when this chap looks at an object, when he looks at his --

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any object for that matter, it goes to the visual areas and,

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however, and it's processed in the fusiform gyrus,

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and you recognize it as a pea plant, or a table,

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or your mother, for that matter, OK?

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And then the message cascades into the amygdala,

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and then goes down the autonomic nervous system.

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But maybe, in this chap, that wire that goes from the amygdala to the limbic system,

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the emotional core of the brain, is cut by the accident.

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So because the fusiform is intact,

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the chap can still recognize his mother,

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and says, "Oh yeah, this looks like my mother."

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But because the wire is cut to the emotional centers,

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he says, "But how come, if it's my mother, I don't experience a warmth?"

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Or terror, as the case may be? Right?

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(Laughter)

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And therefore, he says, "How do I account for this inexplicable lack of emotions?

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This can't be my mother.

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It's some strange woman pretending to be my mother."

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How do you test this?

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Well, what you do is, if you take any one of you here, and put you in front of a screen,

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and measure your galvanic skin response,

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and show pictures on the screen,

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I can measure how you sweat when you see an object,

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like a table or an umbrella. Of course, you don't sweat.

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If I show you a picture of a lion, or a tiger, or a pinup, you start sweating, right?

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And, believe it or not, if I show you a picture of your mother --

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I'm talking about normal people -- you start sweating.

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You don't even have to be Jewish.

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(Laughter)

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Now, what happens if you show this patient?

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You take the patient and show him pictures on the screen

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and measure his galvanic skin response.

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Tables and chairs and lint, nothing happens, as in normal people,

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but when you show him a picture of his mother,

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the galvanic skin response is flat.

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There's no emotional reaction to his mother,

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because that wire going from the visual areas to the emotional centers is cut.

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So his vision is normal because the visual areas are normal,

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his emotions are normal -- he'll laugh, he'll cry, so on and so forth --

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but the wire from vision to emotions is cut

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and therefore he has this delusion that his mother is an impostor.

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It's a lovely example of the sort of thing we do:

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take a bizarre, seemingly incomprehensible, neural psychiatric syndrome

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and say that the standard Freudian view is wrong,

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that, in fact, you can come up with a precise explanation

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in terms of the known neural anatomy of the brain.

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By the way, if this patient then goes,

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and mother phones from an adjacent room -- phones him --

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and he picks up the phone, and he says, "Wow, mom, how are you? Where are you?"

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There's no delusion through the phone.

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Then, she approaches him after an hour, he says, "Who are you?

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You look just like my mother." OK?

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The reason is there's a separate pathway

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going from the hearing centers in the brain to the emotional centers,

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and that's not been cut by the accident.

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So this explains why through the phone he recognizes his mother, no problem.

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When he sees her in person, he says it's an impostor.

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OK, how is all this complex circuitry set up in the brain?

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Is it nature, genes, or is it nurture?

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And we approach this problem

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by considering another curious syndrome called phantom limb.

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And you all know what a phantom limb is.

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When an arm is amputated, or a leg is amputated, for gangrene,

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or you lose it in war -- for example, in the Iraq war,

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it's now a serious problem --

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you continue to vividly feel the presence of that missing arm,

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and that's called a phantom arm or a phantom leg.

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In fact, you can get a phantom with almost any part of the body.

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Believe it or not, even with internal viscera.

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I've had patients with the uterus removed -- hysterectomy --

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who have a phantom uterus, including phantom menstrual cramps

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at the appropriate time of the month.

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And in fact, one student asked me the other day,

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"Do they get phantom PMS?"

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(Laughter)

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A subject ripe for scientific enquiry, but we haven't pursued that.

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OK, now the next question is,

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what can you learn about phantom limbs by doing experiments?

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One of the things we've found was,

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about half the patients with phantom limbs

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claim that they can move the phantom.

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It'll pat his brother on the shoulder,

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it'll answer the phone when it rings, it'll wave goodbye.

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These are very compelling, vivid sensations.

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The patient's not delusional.

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He knows that the arm is not there,

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but, nevertheless, it's a compelling sensory experience for the patient.

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But however, about half the patients, this doesn't happen.

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The phantom limb -- they'll say, "But doctor, the phantom limb is paralyzed.

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It's fixed in a clenched spasm and it's excruciatingly painful.

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If only I could move it, maybe the pain will be relieved."

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Now, why would a phantom limb be paralyzed?

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It sounds like an oxymoron.

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But when we were looking at the case sheets, what we found was,

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these people with the paralyzed phantom limbs,

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the original arm was paralyzed because of the peripheral nerve injury.

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The actual nerve supplying the arm was severed,

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was cut, by say, a motorcycle accident.

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So the patient had an actual arm, which is painful,

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in a sling for a few months or a year, and then,

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in a misguided attempt to get rid of the pain in the arm,

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the surgeon amputates the arm,

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and then you get a phantom arm with the same pains, right?

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And this is a serious clinical problem.

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Patients become depressed.

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Some of them are driven to suicide, OK?

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So, how do you treat this syndrome?

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Now, why do you get a paralyzed phantom limb?

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When I looked at the case sheet, I found that they had an actual arm,

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and the nerves supplying the arm had been cut,

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and the actual arm had been paralyzed,

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and lying in a sling for several months before the amputation,

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and this pain then gets carried over into the phantom itself.

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00:11:40,000 --> 00:11:42,000
Why does this happen?

246
00:11:42,000 --> 00:11:44,000
When the arm was intact, but paralyzed,

247
00:11:44,000 --> 00:11:47,000
the brain sends commands to the arm, the front of the brain, saying, "Move,"

248
00:11:47,000 --> 00:11:49,000
but it's getting visual feedback saying, "No."

249
00:11:49,000 --> 00:11:53,000
Move. No. Move. No. Move. No.

250
00:11:53,000 --> 00:11:56,000
And this gets wired into the circuitry of the brain,

251
00:11:56,000 --> 00:11:59,000
and we call this learned paralysis, OK?

252
00:11:59,000 --> 00:12:03,000
The brain learns, because of this Hebbian, associative link,

253
00:12:03,000 --> 00:12:06,000
that the mere command to move the arm

254
00:12:06,000 --> 00:12:08,000
creates a sensation of a paralyzed arm.

255
00:12:08,000 --> 00:12:10,000
And then, when you've amputated the arm,

256
00:12:10,000 --> 00:12:14,000
this learned paralysis carries over into your body image

257
00:12:14,000 --> 00:12:17,000
and into your phantom, OK?

258
00:12:17,000 --> 00:12:19,000
Now, how do you help these patients?

259
00:12:19,000 --> 00:12:21,000
How do you unlearn the learned paralysis,

260
00:12:21,000 --> 00:12:25,000
so you can relieve him of this excruciating, clenching spasm

261
00:12:25,000 --> 00:12:27,000
of the phantom arm?

262
00:12:27,000 --> 00:12:32,000
Well, we said, what if you now send the command to the phantom,

263
00:12:32,000 --> 00:12:36,000
but give him visual feedback that it's obeying his command, right?

264
00:12:36,000 --> 00:12:39,000
Maybe you can relieve the phantom pain, the phantom cramp.

265
00:12:39,000 --> 00:12:41,000
How do you do that? Well, virtual reality.

266
00:12:41,000 --> 00:12:43,000
But that costs millions of dollars.

267
00:12:43,000 --> 00:12:46,000
So, I hit on a way of doing this for three dollars,

268
00:12:46,000 --> 00:12:48,000
but don't tell my funding agencies.

269
00:12:48,000 --> 00:12:49,000
(Laughter)

270
00:12:49,000 --> 00:12:53,000
OK? What you do is you create what I call a mirror box.

271
00:12:53,000 --> 00:12:55,000
You have a cardboard box with a mirror in the middle,

272
00:12:55,000 --> 00:12:59,000
and then you put the phantom -- so my first patient, Derek, came in.

273
00:12:59,000 --> 00:13:02,000
He had his arm amputated 10 years ago.

274
00:13:02,000 --> 00:13:05,000
He had a brachial avulsion, so the nerves were cut

275
00:13:05,000 --> 00:13:09,000
and the arm was paralyzed, lying in a sling for a year, and then the arm was amputated.

276
00:13:09,000 --> 00:13:11,000
He had a phantom arm, excruciatingly painful, and he couldn't move it.

277
00:13:11,000 --> 00:13:13,000
It was a paralyzed phantom arm.

278
00:13:13,000 --> 00:13:17,000
So he came there, and I gave him a mirror like that, in a box,

279
00:13:17,000 --> 00:13:20,000
which I call a mirror box, right?

280
00:13:20,000 --> 00:13:23,000
And the patient puts his phantom left arm,

281
00:13:23,000 --> 00:13:25,000
which is clenched and in spasm, on the left side of the mirror,

282
00:13:25,000 --> 00:13:27,000
and the normal hand on the right side of the mirror,

283
00:13:27,000 --> 00:13:31,000
and makes the same posture, the clenched posture,

284
00:13:31,000 --> 00:13:34,000
and looks inside the mirror. And what does he experience?

285
00:13:34,000 --> 00:13:37,000
He looks at the phantom being resurrected,

286
00:13:37,000 --> 00:13:41,000
because he's looking at the reflection of the normal arm in the mirror,

287
00:13:41,000 --> 00:13:43,000
and it looks like this phantom has been resurrected.

288
00:13:43,000 --> 00:13:46,000
"Now," I said, "now, look, wiggle your phantom --

289
00:13:46,000 --> 00:13:50,000
your real fingers, or move your real fingers while looking in the mirror."

290
00:13:50,000 --> 00:13:54,000
He's going to get the visual impression that the phantom is moving, right?

291
00:13:54,000 --> 00:13:56,000
That's obvious, but the astonishing thing is,

292
00:13:56,000 --> 00:13:59,000
the patient then says, "Oh my God, my phantom is moving again,

293
00:13:59,000 --> 00:14:01,000
and the pain, the clenching spasm, is relieved."

294
00:14:01,000 --> 00:14:04,000
And remember, my first patient who came in --

295
00:14:04,000 --> 00:14:05,000
(Applause)

296
00:14:05,000 --> 00:14:09,000
-- thank you. (Applause)

297
00:14:09,000 --> 00:14:12,000
My first patient came in, and he looked in the mirror,

298
00:14:12,000 --> 00:14:15,000
and I said, "Look at your reflection of your phantom."

299
00:14:15,000 --> 00:14:17,000
And he started giggling, he says, "I can see my phantom."

300
00:14:17,000 --> 00:14:19,000
But he's not stupid. He knows it's not real.

301
00:14:19,000 --> 00:14:21,000
He knows it's a mirror reflection,

302
00:14:21,000 --> 00:14:23,000
but it's a vivid sensory experience.

303
00:14:23,000 --> 00:14:26,000
Now, I said, "Move your normal hand and phantom."

304
00:14:26,000 --> 00:14:28,000
He said, "Oh, I can't move my phantom. You know that. It's painful."

305
00:14:28,000 --> 00:14:30,000
I said, "Move your normal hand."

306
00:14:30,000 --> 00:14:32,000
And he says, "Oh my God, my phantom is moving again. I don't believe this!

307
00:14:32,000 --> 00:14:35,000
And my pain is being relieved." OK?

308
00:14:35,000 --> 00:14:36,000
And then I said, "Close your eyes."

309
00:14:36,000 --> 00:14:38,000
He closes his eyes.

310
00:14:38,000 --> 00:14:39,000
"And move your normal hand."

311
00:14:39,000 --> 00:14:40,000
"Oh, nothing. It's clenched again."

312
00:14:40,000 --> 00:14:42,000
"OK, open your eyes."

313
00:14:42,000 --> 00:14:43,000
"Oh my God, oh my God, it's moving again!"

314
00:14:43,000 --> 00:14:45,000
So, he was like a kid in a candy store.

315
00:14:45,000 --> 00:14:50,000
So, I said, OK, this proves my theory about learned paralysis

316
00:14:50,000 --> 00:14:52,000
and the critical role of visual input,

317
00:14:52,000 --> 00:14:54,000
but I'm not going to get a Nobel Prize

318
00:14:54,000 --> 00:14:56,000
for getting somebody to move his phantom limb.

319
00:14:56,000 --> 00:14:57,000
(Laughter)

320
00:14:57,000 --> 00:14:58,000
(Applause)

321
00:14:58,000 --> 00:15:01,000
It's a completely useless ability, if you think about it.

322
00:15:01,000 --> 00:15:02,000
(Laughter)

323
00:15:02,000 --> 00:15:06,000
But then I started realizing, maybe other kinds of paralysis

324
00:15:06,000 --> 00:15:11,000
that you see in neurology, like stroke, focal dystonias --

325
00:15:11,000 --> 00:15:13,000
there may be a learned component to this,

326
00:15:13,000 --> 00:15:16,000
which you can overcome with the simple device of using a mirror.

327
00:15:16,000 --> 00:15:18,000
So, I said, "Look, Derek" --

328
00:15:18,000 --> 00:15:21,000
well, first of all, the guy can't just go around carrying a mirror to alleviate his pain --

329
00:15:21,000 --> 00:15:25,000
I said, "Look, Derek, take it home and practice with it for a week or two.

330
00:15:25,000 --> 00:15:27,000
Maybe, after a period of practice,

331
00:15:27,000 --> 00:15:29,000
you can dispense with the mirror, unlearn the paralysis,

332
00:15:29,000 --> 00:15:31,000
and start moving your paralyzed arm,

333
00:15:31,000 --> 00:15:33,000
and then, relieve yourself of pain."

334
00:15:33,000 --> 00:15:35,000
So he said OK, and he took it home.

335
00:15:35,000 --> 00:15:37,000
I said, "Look, it's, after all, two dollars. Take it home."

336
00:15:37,000 --> 00:15:40,000
So, he took it home, and after two weeks, he phones me,

337
00:15:40,000 --> 00:15:42,000
and he said, "Doctor, you're not going to believe this."

338
00:15:42,000 --> 00:15:43,000
I said, "What?"

339
00:15:43,000 --> 00:15:45,000
He said, "It's gone."

340
00:15:45,000 --> 00:15:46,000
I said, "What's gone?"

341
00:15:46,000 --> 00:15:48,000
I thought maybe the mirror box was gone.

342
00:15:48,000 --> 00:15:49,000
(Laughter)

343
00:15:49,000 --> 00:15:52,000
He said, "No, no, no, you know this phantom I've had for the last 10 years?

344
00:15:52,000 --> 00:15:54,000
It's disappeared."

345
00:15:54,000 --> 00:15:56,000
And I said -- I got worried, I said, my God,

346
00:15:56,000 --> 00:15:58,000
I mean I've changed this guy's body image,

347
00:15:58,000 --> 00:16:01,000
what about human subjects, ethics and all of that?

348
00:16:01,000 --> 00:16:03,000
And I said, "Derek, does this bother you?"

349
00:16:03,000 --> 00:16:06,000
He said, "No, last three days, I've not had a phantom arm

350
00:16:06,000 --> 00:16:09,000
and therefore no phantom elbow pain, no clenching,

351
00:16:09,000 --> 00:16:12,000
no phantom forearm pain, all those pains are gone away.

352
00:16:12,000 --> 00:16:16,000
But the problem is I still have my phantom fingers dangling from the shoulder,

353
00:16:16,000 --> 00:16:18,000
and your box doesn't reach."

354
00:16:18,000 --> 00:16:19,000
(Laughter)

355
00:16:19,000 --> 00:16:22,000
"So, can you change the design and put it on my forehead,

356
00:16:22,000 --> 00:16:25,000
so I can, you know, do this and eliminate my phantom fingers?"

357
00:16:25,000 --> 00:16:27,000
He thought I was some kind of magician.

358
00:16:27,000 --> 00:16:28,000
Now, why does this happen?

359
00:16:28,000 --> 00:16:31,000
It's because the brain is faced with tremendous sensory conflict.

360
00:16:31,000 --> 00:16:34,000
It's getting messages from vision saying the phantom is back.

361
00:16:34,000 --> 00:16:36,000
On the other hand, there's no proprioception,

362
00:16:36,000 --> 00:16:40,000
muscle signals saying that there is no arm, right?

363
00:16:40,000 --> 00:16:42,000
And your motor command saying there is an arm,

364
00:16:42,000 --> 00:16:45,000
and, because of this conflict, the brain says, to hell with it,

365
00:16:45,000 --> 00:16:48,000
there is no phantom, there is no arm, right?

366
00:16:48,000 --> 00:16:50,000
It goes into a sort of denial -- it gates the signals.

367
00:16:50,000 --> 00:16:54,000
And when the arm disappears, the bonus is, the pain disappears

368
00:16:54,000 --> 00:16:58,000
because you can't have disembodied pain floating out there, in space.

369
00:16:58,000 --> 00:17:00,000
So, that's the bonus.

370
00:17:00,000 --> 00:17:02,000
Now, this technique has been tried on dozens of patients

371
00:17:02,000 --> 00:17:04,000
by other groups in Helsinki,

372
00:17:04,000 --> 00:17:07,000
so it may prove to be valuable as a treatment for phantom pain,

373
00:17:07,000 --> 00:17:09,000
and indeed, people have tried it for stroke rehabilitation.

374
00:17:09,000 --> 00:17:12,000
Stroke you normally think of as damage to the fibers,

375
00:17:12,000 --> 00:17:14,000
nothing you can do about it.

376
00:17:14,000 --> 00:17:19,000
But, it turns out some component of stroke paralysis is also learned paralysis,

377
00:17:19,000 --> 00:17:22,000
and maybe that component can be overcome using mirrors.

378
00:17:22,000 --> 00:17:24,000
This has also gone through clinical trials,

379
00:17:24,000 --> 00:17:26,000
helping lots and lots of patients.

380
00:17:26,000 --> 00:17:30,000
OK, let me switch gears now to the third part of my talk,

381
00:17:30,000 --> 00:17:34,000
which is about another curious phenomenon called synesthesia.

382
00:17:34,000 --> 00:17:37,000
This was discovered by Francis Galton in the nineteenth century.

383
00:17:37,000 --> 00:17:39,000
He was a cousin of Charles Darwin.

384
00:17:39,000 --> 00:17:41,000
He pointed out that certain people in the population,

385
00:17:41,000 --> 00:17:45,000
who are otherwise completely normal, had the following peculiarity:

386
00:17:45,000 --> 00:17:48,000
every time they see a number, it's colored.

387
00:17:48,000 --> 00:17:52,000
Five is blue, seven is yellow, eight is chartreuse,

388
00:17:52,000 --> 00:17:54,000
nine is indigo, OK?

389
00:17:54,000 --> 00:17:57,000
Bear in mind, these people are completely normal in other respects.

390
00:17:57,000 --> 00:18:00,000
Or C sharp -- sometimes, tones evoke color.

391
00:18:00,000 --> 00:18:03,000
C sharp is blue, F sharp is green,

392
00:18:03,000 --> 00:18:06,000
another tone might be yellow, right?

393
00:18:06,000 --> 00:18:08,000
Why does this happen?

394
00:18:08,000 --> 00:18:10,000
This is called synesthesia. Galton called it synesthesia,

395
00:18:10,000 --> 00:18:12,000
a mingling of the senses.

396
00:18:12,000 --> 00:18:14,000
In us, all the senses are distinct.

397
00:18:14,000 --> 00:18:16,000
These people muddle up their senses.

398
00:18:16,000 --> 00:18:17,000
Why does this happen?

399
00:18:17,000 --> 00:18:19,000
One of the two aspects of this problem are very intriguing.

400
00:18:19,000 --> 00:18:21,000
Synesthesia runs in families,

401
00:18:21,000 --> 00:18:24,000
so Galton said this is a hereditary basis, a genetic basis.

402
00:18:24,000 --> 00:18:28,000
Secondly, synesthesia is about -- and this is what gets me to my point

403
00:18:28,000 --> 00:18:31,000
about the main theme of this lecture, which is about creativity --

404
00:18:31,000 --> 00:18:36,000
synesthesia is eight times more common among artists, poets, novelists

405
00:18:36,000 --> 00:18:39,000
and other creative people than in the general population.

406
00:18:39,000 --> 00:18:40,000
Why would that be?

407
00:18:40,000 --> 00:18:42,000
I'm going to answer that question.

408
00:18:42,000 --> 00:18:44,000
It's never been answered before.

409
00:18:44,000 --> 00:18:45,000
OK, what is synesthesia? What causes it?

410
00:18:45,000 --> 00:18:46,000
Well, there are many theories.

411
00:18:46,000 --> 00:18:48,000
One theory is they're just crazy.

412
00:18:48,000 --> 00:18:51,000
Now, that's not really a scientific theory, so we can forget about it.

413
00:18:51,000 --> 00:18:55,000
Another theory is they are acid junkies and potheads, right?

414
00:18:55,000 --> 00:18:57,000
Now, there may be some truth to this,

415
00:18:57,000 --> 00:18:59,000
because it's much more common here in the Bay Area than in San Diego.

416
00:18:59,000 --> 00:19:00,000
(Laughter)

417
00:19:00,000 --> 00:19:03,000
OK. Now, the third theory is that --

418
00:19:03,000 --> 00:19:08,000
well, let's ask ourselves what's really going on in synesthesia. All right?

419
00:19:08,000 --> 00:19:11,000
So, we found that the color area and the number area

420
00:19:11,000 --> 00:19:14,000
are right next to each other in the brain, in the fusiform gyrus.

421
00:19:14,000 --> 00:19:16,000
So we said, there's some accidental cross wiring

422
00:19:16,000 --> 00:19:19,000
between color and numbers in the brain.

423
00:19:19,000 --> 00:19:22,000
So, every time you see a number, you see a corresponding color,

424
00:19:22,000 --> 00:19:24,000
and that's why you get synesthesia.

425
00:19:24,000 --> 00:19:26,000
Now remember -- why does this happen?

426
00:19:26,000 --> 00:19:28,000
Why would there be crossed wires in some people?

427
00:19:28,000 --> 00:19:30,000
Remember I said it runs in families?

428
00:19:30,000 --> 00:19:32,000
That gives you the clue.

429
00:19:32,000 --> 00:19:34,000
And that is, there is an abnormal gene,

430
00:19:34,000 --> 00:19:37,000
a mutation in the gene that causes this abnormal cross wiring.

431
00:19:37,000 --> 00:19:39,000
In all of us, it turns out

432
00:19:39,000 --> 00:19:43,000
we are born with everything wired to everything else.

433
00:19:43,000 --> 00:19:46,000
So, every brain region is wired to every other region,

434
00:19:46,000 --> 00:19:48,000
and these are trimmed down to create

435
00:19:48,000 --> 00:19:51,000
the characteristic modular architecture of the adult brain.

436
00:19:51,000 --> 00:19:53,000
So, if there's a gene causing this trimming

437
00:19:53,000 --> 00:19:55,000
and if that gene mutates,

438
00:19:55,000 --> 00:19:58,000
then you get deficient trimming between adjacent brain areas.

439
00:19:58,000 --> 00:20:01,000
And if it's between number and color, you get number-color synesthesia.

440
00:20:01,000 --> 00:20:04,000
If it's between tone and color, you get tone-color synesthesia.

441
00:20:04,000 --> 00:20:06,000
So far, so good.

442
00:20:06,000 --> 00:20:08,000
Now, what if this gene is expressed everywhere in the brain,

443
00:20:08,000 --> 00:20:09,000
so everything is cross-connected?

444
00:20:09,000 --> 00:20:15,000
Well, think about what artists, novelists and poets have in common,

445
00:20:15,000 --> 00:20:18,000
the ability to engage in metaphorical thinking,

446
00:20:18,000 --> 00:20:20,000
linking seemingly unrelated ideas,

447
00:20:20,000 --> 00:20:23,000
such as, "It is the east, and Juliet is the Sun."

448
00:20:23,000 --> 00:20:25,000
Well, you don't say, Juliet is the sun,

449
00:20:25,000 --> 00:20:27,000
does that mean she's a glowing ball of fire?

450
00:20:27,000 --> 00:20:30,000
I mean, schizophrenics do that, but it's a different story, right?

451
00:20:30,000 --> 00:20:33,000
Normal people say, she's warm like the sun,

452
00:20:33,000 --> 00:20:35,000
she's radiant like the sun, she's nurturing like the sun.

453
00:20:35,000 --> 00:20:37,000
Instantly, you've found the links.

454
00:20:37,000 --> 00:20:40,000
Now, if you assume that this greater cross wiring

455
00:20:40,000 --> 00:20:43,000
and concepts are also in different parts of the brain,

456
00:20:43,000 --> 00:20:46,000
then it's going to create a greater propensity

457
00:20:46,000 --> 00:20:49,000
towards metaphorical thinking and creativity

458
00:20:49,000 --> 00:20:51,000
in people with synesthesia.

459
00:20:51,000 --> 00:20:54,000
And, hence, the eight times more common incidence of synesthesia

460
00:20:54,000 --> 00:20:56,000
among poets, artists and novelists.

461
00:20:56,000 --> 00:20:59,000
OK, it's a very phrenological view of synesthesia.

462
00:20:59,000 --> 00:21:01,000
The last demonstration -- can I take one minute?

463
00:21:01,000 --> 00:21:03,000
(Applause)

464
00:21:03,000 --> 00:21:08,000
OK. I'm going to show you that you're all synesthetes, but you're in denial about it.

465
00:21:08,000 --> 00:21:12,000
Here's what I call Martian alphabet. Just like your alphabet,

466
00:21:12,000 --> 00:21:15,000
A is A, B is B, C is C.

467
00:21:15,000 --> 00:21:18,000
Different shapes for different phonemes, right?

468
00:21:18,000 --> 00:21:20,000
Here, you've got Martian alphabet.

469
00:21:20,000 --> 00:21:22,000
One of them is Kiki, one of them is Bouba.

470
00:21:22,000 --> 00:21:24,000
Which one is Kiki and which one is Bouba?

471
00:21:24,000 --> 00:21:26,000
How many of you think that's Kiki and that's Bouba? Raise your hands.

472
00:21:26,000 --> 00:21:28,000
Well, it's one or two mutants.

473
00:21:28,000 --> 00:21:29,000
(Laughter)

474
00:21:29,000 --> 00:21:31,000
How many of you think that's Bouba, that's Kiki? Raise your hands.

475
00:21:31,000 --> 00:21:33,000
Ninety-nine percent of you.

476
00:21:33,000 --> 00:21:35,000
Now, none of you is a Martian. How did you do that?

477
00:21:35,000 --> 00:21:40,000
It's because you're all doing a cross-model synesthetic abstraction,

478
00:21:40,000 --> 00:21:44,000
meaning you're saying that that sharp inflection -- ki-ki,

479
00:21:44,000 --> 00:21:49,000
in your auditory cortex, the hair cells being excited -- Kiki,

480
00:21:49,000 --> 00:21:52,000
mimics the visual inflection, sudden inflection of that jagged shape.

481
00:21:52,000 --> 00:21:55,000
Now, this is very important, because what it's telling you

482
00:21:55,000 --> 00:21:57,000
is your brain is engaging in a primitive --

483
00:21:57,000 --> 00:21:59,000
it's just -- it looks like a silly illusion,

484
00:21:59,000 --> 00:22:03,000
but these photons in your eye are doing this shape,

485
00:22:03,000 --> 00:22:06,000
and hair cells in your ear are exciting the auditory pattern,

486
00:22:06,000 --> 00:22:11,000
but the brain is able to extract the common denominator.

487
00:22:11,000 --> 00:22:13,000
It's a primitive form of abstraction,

488
00:22:13,000 --> 00:22:18,000
and we now know this happens in the fusiform gyrus of the brain,

489
00:22:18,000 --> 00:22:19,000
because when that's damaged,

490
00:22:19,000 --> 00:22:23,000
these people lose the ability to engage in Bouba Kiki,

491
00:22:23,000 --> 00:22:25,000
but they also lose the ability to engage in metaphor.

492
00:22:25,000 --> 00:22:29,000
If you ask this guy, what -- "all that glitters is not gold,"

493
00:22:29,000 --> 00:22:31,000
what does that mean?"

494
00:22:31,000 --> 00:22:33,000
The patient says, "Well, if it's metallic and shiny, it doesn't mean it's gold.

495
00:22:33,000 --> 00:22:36,000
You have to measure its specific gravity, OK?"

496
00:22:36,000 --> 00:22:39,000
So, they completely miss the metaphorical meaning.

497
00:22:39,000 --> 00:22:42,000
So, this area is about eight times the size in higher --

498
00:22:42,000 --> 00:22:45,000
especially in humans -- as in lower primates.

499
00:22:45,000 --> 00:22:48,000
Something very interesting is going on here in the angular gyrus,

500
00:22:48,000 --> 00:22:51,000
because it's the crossroads between hearing, vision and touch,

501
00:22:51,000 --> 00:22:55,000
and it became enormous in humans. And something very interesting is going on.

502
00:22:55,000 --> 00:22:58,000
And I think it's a basis of many uniquely human abilities

503
00:22:58,000 --> 00:23:01,000
like abstraction, metaphor and creativity.

504
00:23:01,000 --> 00:23:04,000
All of these questions that philosophers have been studying for millennia,

505
00:23:04,000 --> 00:23:08,000
we scientists can begin to explore by doing brain imaging,

506
00:23:08,000 --> 00:23:10,000
and by studying patients and asking the right questions.

507
00:23:10,000 --> 00:23:12,000
Thank you.

508
00:23:12,000 --> 00:23:13,000
(Applause)

509
00:23:13,000 --> 00:23:14,000
Sorry about that.

510
00:23:14,000 --> 00:23:15,000
(Laughter)