-
For a long time, it was believed that the human brain was fixed or hardwired
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and most forms of brain damage were therefore permanent and irreversible.
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However, scientists have since come to realize that far from being fixed,
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the brain has remarkable powers to regenerate itself even in old age.
-
Norman Doidge is a psychiatrist and medical researcher.
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In his new book, he explores the impact of this revolutionary discovery on all of us.
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It's called "The Brain That Changes Itself."
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Stories of personal triumph from the frontiers of brain science.
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For years, we've been told that the human brain is like a machine,
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a computer that there are different parts
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that they're responsible for different functions.
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And if those parts break or wear down or damaged, we lose that function.
-
Now, in your new book, you throw this all on its head and you say that in fact,
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the brain is plastic,
-
explain what that means.
-
Well, plastic means plastic in the sense of Plasticine,
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modifiable, adaptable.
-
The plastic brain is a brain that can
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change its structure and its function depending on
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both...
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Without drugs or invasive...
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Without drugs. Just depending on what you do with your brain.
-
The task at hand that you are working on,
-
what you're perceiving can cause you to change the structure of your brain
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on many levels
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and this is the most fantastic part,
-
what you think and imagine actually can change the structure of your brain
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down
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to the very connections between the brain cells, down into the genes
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even for instance.
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One of the most,
-
you know,
-
staggeringly interesting discoveries of the late
-
20th century was the discovery that learning
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changes the number of connections between the neurons,
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the nerve cells in a nervous system.
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You can go, for instance, from having perhaps 1300
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connections between
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nerve cell A and nerve cell B to 2700
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with several hours of training. By virtue of more brain activity occurring,
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By virtue of learning and brain activity. So,
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what happens is thoughts
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or activities that you do with your brain
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actually turn certain genes on and others off inside the nerve
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cells, which then make proteins which then change the structure.
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Now,
-
why is this discovery considered so revolutionary and more particularly what
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are the implications of this discovery for people with brain dysfunction?
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A stroke for example. When you had a stroke, the general assumption was
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your brain got swollen, the chemicals were kind of deranged and after a few weeks,
-
whatever you were left with was what you would have
-
to live with for the rest of your life.
-
You basically lost that brain
-
function that was damaged. The cells died, they couldn't be replaced,
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the healthy ones around it couldn't reorganize.
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And so,
-
we were kind of waiting for the swelling to
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go away and rehab was just sort of focused on
-
getting you over that period. Now, we know that rehab can actually
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reorganize the brain if it's done properly and bring many new functions back.
-
But if I could just say it, it also meant
-
that
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as you started to get older and your brain started to decline.
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It was like a machine that was wearing out
-
and the attempt to exercise your brain in the second half
-
of life was really kind of unwarranted or waste of time.
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And so, we just
-
accepted a view of human development in which
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the second half of life is a period of necessary mental decline.
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And then, of course, the whole view of human nature that we have, you know,
-
since the rise of modern science, most
-
educated people see human nature in some way is emerging from the human brain.
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And if the human brain was fixed, immutable
-
and a rigid structure,
-
it made a lot of sense to think of human nature as fundamentally fixed.
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And so,
-
we have to re-examine all that and I begin to do that in this book.
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Well, you do it by way of story and that there's some remarkable,
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almost logic defying, remarkable,
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given what our traditional notion of what the brain is,
-
probably the most remarkable.
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And it is the story of a woman who was born with half a brain. Tell me about Michelle.
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I went to visit Michelle because I thought that
-
I knew that she was born with one hemisphere alone,
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just half a brain.
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And,
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I thought that whatever changes that she was able
-
to undergo would really test this notion of
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plasticity, certainly, at least in early life.
-
And
-
basically, when she was in the womb, some catastrophic event occurred, so
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her left hemisphere never developed.
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And
-
based on what, you know, the usual view of
-
that
-
the brain basically has certain areas which in the left
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hemisphere which are responsible for speech and other functions,
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someone with that level of damage you would imagine
-
would be unable to speak, unable to think, they might be alive, but on a respirator.
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And it turns out that that's not the case with Michelle.
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In fact,
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if you met Michelle,
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you would detect some subtle things like one of her arms is a little twisted,
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et cetera
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and
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her speech when she's upset, it's a little repetitive,
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but you would never dream.
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And nor did the people who examined her for a number of years dream
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that she had half a brain. Well, explain to this
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now, if we had thought that
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this part of the brain is responsible for speech
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and I don't have this part of the brain,
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How is Michelle speaking?
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We know that there's a lot of plasticity early in life.
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But we also know and I make this very clear in the book,
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there's plasticity from cradle to grave.
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But you know, there are waves of increased plasticity
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and it turns out that what the brain does is
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it learns how to do what it's got to do at the time. So,
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parts of the brain that might have been
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devoted to other things will learn how to move.
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If it has to see to survive, they'll be devoted to vision.
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And so
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all
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these things can actually be organized and move around,
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these higher mental functions. To give our viewers even more
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kind of appreciation of the extent to which
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that's possible.
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Retell the story that's in the book that
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you dub the woman who is perpetually falling.
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Cheryl Schiltz
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was a woman.
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She had a hysterectomy and she was given
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a medication because she developed an infection called gentamicin
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and
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it poisoned the vestibular apparatus, which is the balance apparatus in her brain.
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And if you lose your sense of balance,
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you will feel like you're perpetually falling. When I was with Cheryl at one point,
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I asked her, "What's it like when you've finally fallen to the floor?
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What do you feel at that point?"
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And then she says,
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"Sometimes, I just feel the floor opens up and I fall into a perpetual abyss."
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So that was her life and she ended up on disability.
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And one of the great
-
people
-
who were at the cutting edge,
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I call these people "neuroplastician" to coin a phrase,
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Paul
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Bach-y-Rita
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invented a mechanism
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and I was there when she was using the mechanism for one
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of the first times that basically was attached to an accelerometer.
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An accelerometer is like a gyroscope.
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And
-
she would...
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The accelerometer would be in a hat on her head. Like a construction hat.
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Like a construction hat.
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And it would give signals that went into her tongue of all places
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telling her where she was in space. I tried it on.
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So when you lean forward and you feel like champagne bubbles,
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they're really little electric shocks, tell you you're forward, you lean back,
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it goes back
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and she would put this hat on.
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And
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immediately
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she would... Normally, she'd be holding herself like up on a table lest she fall
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and immediately her whole body relaxed.
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And this seemed like a miracle. Why? Because
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the sensory
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apparatus, the
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sense of touch on the tongue goes to a
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different part of the brain and the balance apparatus.
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So
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somehow or rather these signals coming in
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were making new pathways or strengthening very dormant pathways between
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her sense of touch and her sense of balance,
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so that was the first miracle I saw that happening and she had tried it on.
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But
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then there was a second miracle which
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is as she started to use the machine more,
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she found she had a residual period
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where
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she would take the hat off.
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And at first, the residual period lasted
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30 seconds. Residual period being that she still had balance. (MULTIPLE VOICES).
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Exactly.
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That's
-
right.
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It lasted for, you know, a few seconds and then
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it lasted longer and longer.
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And as she started to use the hat and take it home and use it,
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she would be going for days. And
-
that was a true miracle because what was happening was
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a miracle. I mean,
-
it's only a miracle
-
if you think that the brain is fixed, it's actually not a miracle.
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because
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she now no longer considers herself a
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wobbler. Because the brain reordered itself and put
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the balance in a different part of the brain that wasn't then.
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Yeah. And, it developed new paths. Now, is this sensory substitution?
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I mean, this is again,
-
another fascinating notion he introduces. This is what
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Paul
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Bach-y-Rita called sensory substitution. He did
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this
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as well for people who had been congenitally blind,
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they've never seen anything.
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And,
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he rigged up a camera to a computer and then attached it originally just to the back
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and there were vibrating pixels that were on the back.
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And then he put it in to the tongue
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and he found that he could train a human tongue
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to function like a retina.
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And they would be able to see Twiggy.
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They would say, "Well, that's a picture of Twiggy."
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That's a picture of a vase...you've just moved a vase in front of a telephone,
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they could read certain things.
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If you threw a ball at them, they would duck, they could see perspective.
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I mean, so this is remarkable.
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They could see through the tongue.
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What was happening is the tongue is like a two-dimensional surface
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just as the retina,
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the retina is.
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And yeah,
-
basically...
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The images would be...
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Images would be on the tongue.
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And then, we've recently learned, actually, this was some work also done
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in Canada,
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Bach-y-Rita was from the states
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that
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the input coming into the tongue was processed in the back of the brain,
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which we tend to call the visual cortex.
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So it was all being rerouted
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and
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Paul
-
Bach-y-Rita has found different ways to do sensory substitution, which is
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lay the groundwork for the notion of a retinal implant, but,
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you know, helping other people who have
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literally lost the ability to sense certain things.
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We touched on the whole issue of stroke victims.
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And that you can tell a great story here about a surgeon in
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his mid 50s had a terrible debilitating stroke.
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Tell me how he came back. Michael Bernstein,
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yeah, out, he was playing tennis. He was a tennis...
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He spent the morning doing surgery on the eyes,
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so he needs a lot of fine motor skills. It's microscopic surgery.
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It's in a small confined space.
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Then, he was playing tennis,
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then he developed a stroke and he couldn't move one side of his body.
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He went for conventional rehabilitation,
-
they gave him whatever it was the 4 to 6 weeks.
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And basically, they said you're on your own and he had very,
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very little control of his arm at that point and very little control of his leg,
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and then he tried a new
-
form of treatment. He
-
happened to be from Birmingham,
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Alabama where a man named Edward Taub had
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developed this new treatment called constraint-induced therapy.
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And
-
one of the things that neuroplasticians have shown in hundreds of experiments
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now is that it's use it or lose it brain.
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If you don't use something,
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it's that cortical real estate is taken over by something else.
-
Now,
-
what happens when a very common form
-
of stroke is you have a stroke in the left
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hemisphere and you can't move your
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right hand. You're paralyzed.
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You can't move it well, et cetera.
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And so people try to use their arms,
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it doesn't work
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and
-
so they stopped using them.
-
Now,
-
what Taub did ingeniously was,
-
he got people to put their good hands in slings.
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Constrain them. He constrained them
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and then if a person could just do this,
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he would give them small amounts just to get
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a little more control over that very incremental,
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and he worked them very, very hard.
-
And they would have to do things like, you know, try to wash pots. And,
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you know, people would come in, they couldn't dress themselves, they
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couldn't eat, they couldn't put food on a fork.
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They literally would have been dependent for the rest of their lives.
-
And Michael Bernstein was one of the first to go
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through this and after two weeks of very intensive training,
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and that's not a long time. No. No.
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It
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isn't,
-
He was able to function, get back to work and function as a surgeon.
-
And there are people who went to Taub clinic, there was one person
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I spoke to had
-
a stroke almost 50 years before. He had been
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a little boy playing baseball when he had a stroke.
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They
-
could help him. All these years,
-
after the fact, I mean,
-
that's just so remarkable because that plasticity
-
and the ability to reorganize
-
is in the brain.
-
And it has even helped people who've had traumatic injuries,
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traumatic brain injuries.
-
I think that's the kind of thing that would be very helpful
-
for
-
anyone who's got those kinds... Well, not anyone but many people with
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traumatic brain injuries, for instance,
-
think of the soldiers getting back from Afghanistan.
-
Is this kind of therapy or are these kinds of treatments now finding their way
-
into medical practice?
-
Not quite.
-
No, because normally when someone has a stroke or any kind of brain damage,
-
I mean, we really do look on it very,
-
very fatalistically and if the evidence is what we should, they don't improve.
-
Yeah look.
-
We look on it fatalistically in part because studies that have been
-
done in the past and people with brain damage and strokes showed that
-
interventions didn't work.
-
But now that the neuroplasticians have laid out the laws of this new science,
-
there's reason to be hopeful for a number of kinds
-
of brain injuries.
-
I bet,
-
the notion of phantom pain again
-
documented that people who lose limbs that they continue to
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to hurt.
-
You again claim that
-
neuroplasticity both explains this and that researchers
-
using the theories of neuroplasticity have been able to cure phantom pain.
-
Tell me about that.
-
Well, phantom pain was one of the great mysteries of medicine.
-
How is it possible to feel pain in a limb that isn't there?
-
And what a neurologist named
-
Ramachandran discovered was
-
that in patients who've lost their arms and then
-
get pain or in one case in scratch or itches,
-
What happens is
-
if you remove an arm,
-
there's cortical real estate if you will, that had been devoted to
-
moving that arm and feeling for that arm, it's now dormant.
-
In the brain.
-
In the brain.
-
So adjacent cortical real estate takes it over.
-
And
-
in the typical human body map,
-
an area that's very close to the arm is actually the face. And
-
we now know that phantom pain is often caused because the face maps in the brain
-
say, "Hey, there's more cortical real estate for us and they start to move in there
-
and
-
reorganize
-
the brain." There was one patient he had who had an unscratchable itch,
-
so that was a terrible affliction for him.
-
And
-
Ramachandran eventually figured that if you just scratched the man's cheek,
-
the itch went away. And
-
Ramachandran was able by the way to sort of trick the brain
-
into rewiring itself using this same neuroplasticity.
-
One of the reasons that people would
-
have these frozen pains is because once the input is stopped into the brain
-
from,
-
you know, from the arm,
-
it's as though
-
that's the picture that remains in the brain, there's no
-
new input to say. Now the arm is moving again.
-
Many people who had phantoms
-
felt their arms were frozen and in pain.
-
So, he set up a mirror device where you would look at what your real arm,
-
let's say this arm had been cut off.
-
You'd look at your real arm and then you look into a mirror right here.
-
The brain would be tricking you thinking that your arm was...
-
Think that your left arm was moving, that which, of course, didn't exist,
-
you'd kind of put your stump near it
-
and
-
that rewired the map so that the frozen phantom could move.
-
Now,
-
I understand that neuroplasticity also tells us something
-
about the nature of sexual attraction and love.
-
What is that?
-
There's tremendous variation, of course, in what people are turned on by,
-
let's say sexually, I mean,
-
you know, take
-
situations in other cultures
-
seem unnatural sometimes.
-
And we learned that people can develop attractions. If you think of
-
the whole idea that Chinese men 100 years ago in the aristocracy were
-
totally turned on by women who had their feet broken and bound up.
-
Okay.
-
We start to realize that sexual tastes can be acquired and we
-
we can acquire sexual types.
-
And we're seeing a lot of this happening now actually
-
with the internet and internet porn in a way.
-
You know, there are a lot of stories that started to
-
become
-
public in the nineties about men
-
who would get on the internet
-
and they'd sort of just be searching
-
around and then they fasten on to certain images
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that would really turn them on, that really surprise them.
-
And then they would practice them over and over and over again
-
and they would have orgasms and when a person has an orgasm, they secrete a
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brain chemical called dopamine, which actually reinforces the circuit
-
and rewards them.
-
So, dopamine is a neurotransmitter or a brain chemical
-
that's very involved in consolidating a new circuit.
-
And these men would start to develop new sexual attractions
-
that at times seemed bizarre to them,
-
sometimes they dipped into childhood things.
-
I mean,
-
one story I talked about in the book is
-
a man who developed an attraction to spanking sites.
-
And if you think about it, spanking would seem to have to do with early childhood.
-
But the other thing that was happening for these men and this
-
was reported over and over and I saw it in clinical practice
-
is
-
they said that for a mysterious reason, they were losing
-
interest in
-
their own
-
partners, even though objectively they found them to be attractive.
-
So, here was a case where
-
because of plasticity, people were inadvertently rewiring
-
their brains.
-
And plasticity isn't always a good thing. That it can lead to rigid behaviors (VOICE OVERLAP).
-
And in this case, it leads typically or very frequently to a kind of an addiction.
-
And if you think about it, addictions are about plastic change in the brain.
-
There are certain people who, if they have alcohol,
-
they have a chemical
-
sequence that's fired in their brain and a chemical called delta
-
FosB
-
is released
-
that changes their brain permanently.
-
That's why sometimes it does make sense for a person to say,
-
even though they haven't had a drink for years, I'm an alcoholic.
-
It's in plasticity terms,
-
my brain has been structurally altered by my interactions with alcohol.
-
Now, interesting you say that because they also point out that psychoanalysis
-
can be used
-
to open up the brain's pathways and reorder
-
the brain's function too. I think you call this
-
neuroplastic therapy.
-
Explain to me what that is and how it would work.
-
It turns out, you know, based on what I told you before about,
-
you know, thoughts altering genetic behavior
-
that thoughts in therapy are actually changing brain structure as well.
-
They change different brain structures.
-
But the major therapists that we know that are successful
-
and that includes psychoanalytic therapies, cognitive behavioral therapies,
-
it's something called interpersonal therapy.
-
They're all for slightly different conditions,
-
all
-
rewire the brain, all change the balance in the brain's department.
-
So,
-
they are as every bit as biological, if you were
-
in intervention as the use of drugs and the advantage of psychotherapy is if
-
you don't absolutely need drugs.
-
And I want to say, I mean, I use drugs sometimes
-
but the advantage of them is
-
they
-
don't have as many side effects
-
in general. And,
-
if you think about it, drugs
-
as they are today are very blunt instruments, you take a pill and it goes
-
and it bays every cell in your brain and in fact, in your body,
-
and that's why we get so many side effects.
-
And it would be
-
to a certain extent, if you're using thoughts for the intervention,
-
you're like more like a micro surgeon
-
going into the thought patterns that are probably...
-
Do you know enough about the brain to be that precise in terms of psychiatry
-
and psychoanalysis.
-
In other words, if I make an interpretation about the meaning of behavior, do
-
I know where in the brain
-
it's going?
-
Well if we're treating, let's say an anxiety problem, right?
-
We now know that if you use psychoanalytic psychotherapy
-
and
-
you take a person before the therapy
-
and
-
you
-
take the thing that's making them anxious and you
-
make them think about it or attend to it,
-
the part of the brain that's likely to light up and trigger these
-
sort of bolts of anxiety.
-
And after they go through the therapy, if the therapy works,
-
those parts of the brain aren't triggered. Now you
-
have an absolutely horrifying statistic here about our generation,
-
the baby boomers,
-
those between 40 and 60 that they have over a 50% chance of reaching the age of 85,
-
and that 85-year-olds have a 47% chance of having Alzheimer's.
-
We're going to have a population full of dementia. I mean, what can baby boomers do
-
to enhance their brain power and ward off that disease?
-
Okay.
-
So, there's two things that we worry about when
-
we think of mental decline as we get older.
-
One of them is a more benign thing and more common,
-
it's called age-related cognitive decline.
-
The senior moments that begin in our 50s that
-
frighten people
-
and then there are the serious dementias.
-
So, the good news is that we know for a fact
-
now that age-related cognitive decline is reversible through brain exercises.
-
And I met with a man Stanley
-
Karansky who was 90,
-
who started to have some difficulties
-
with senior moments. His handwriting was sloppy.
-
He was no longer alert, he wasn't socializing much.
-
And
-
in six weeks
-
and
-
roughly
-
an hour a day, he was able to reverse all of that. What was he doing?
-
He was doing a program called Posit Science that I described in the book.
-
Now, this is a company, an actual company.
-
Yeah. Tell me more about because you have been claiming like 80-year-olds to be like 50-year-olds.
-
Well, they've shown it.
-
Posit Science was set up by perhaps
-
the world's leading neuroplastician and
-
neuroplasticity researcher, Michael Merzenich.
-
And,
-
he's already a man of great accomplishment. He was one of
-
the inventors of the cochlear implant that allows the deaf to hear.
-
He's
-
helped kids with learning disabilities,
-
with reading disabilities,
-
moved from problems to basically normal or above normal levels.
-
And they set up a program that rebuilds
-
the auditory cortex,
-
the part of the brain that processes language from scratch in older people.
-
What happens is that we age. One of the reasons that we cannot remember things
-
is
-
our brain maps for sounds
-
are just kind of getting dulled.
-
They need to be tuned up at the very basic level of distinguishing sounds like "ba
-
and da
-
and pa."
-
The reason is we haven't really used them intensively
-
often. Once, we hit middle age, we are usually replaying, mastered skills.
-
But to maintain a brain in good shape,
-
you've got to work as hard as you worked when
-
you were learning a French vocabulary in high school,
-
maybe you didn't work at it, but as hard as you should have worked at.
-
And so people go for decades without
-
putting themselves for that intensive kind of training
-
and
-
the cortex just kind of gets
-
dull and you develop what are called fuzzy engrams.
-
You don't hear the sound of the person's name at the party crisply,
-
so they rebuild it from the ground up. How would our viewers get this program?
-
Posit Science.
-
Just go to put that in the internet and you'll come to the website for that.
-
What do you think the next big breakthrough is in brain research?
-
What's the next big thing we should be watching for?
-
It's the translation of the fundamental laws
-
of brain plasticity into applications for everything
-
in therapeutics, in all kinds of training, you know, that means sports,
-
the military education, anything you want to do and develop
-
Right
-
now
-
basically
-
many of these disciplines have an intuitive grasp of some of the laws of plasticity,
-
but the neuroplasticians can help sharpen and speed up learning.
-
So
-
that's where I imagine it would come.
-
I know that people will want to get
-
very highfalutin and try to facilitate neuroplastic change
-
with chemicals and some of that might be doable.
-
But that's also very problematic for the reason I
-
said that chemicals are still a very blunt instrument.
-
At a personal level,
-
I mean that this book is full of very,
-
not just amazing but inspirational and uplifting stories.
-
I mean,
-
over the course of doing the research,
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did it kind of change your sense of what
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human potential and perhaps even human nature is?
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Yes, it did.
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One of the most important insights I think I had
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while doing the book was what I call the "plastic paradox,"
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and that is this.
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The plasticity,
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the brain is always plastic,
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but it can give rise to both flexible or rigid behaviors.
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It can give rise to rigid behaviors because once those networks are established,
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they
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tend to out compete the other one in a
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war of nerves that's going on inside our head.
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You know, the human brain is a habit-forming thing.
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So,
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the way to understand plasticity is think of it as like a hill,
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snow on a hill in winter, and we want to ski down that hill,
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so we get to the top of it. Because the snow is plastic or pliable,
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we can take many paths down that hill,
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but it being a hill,
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it has rocks and trees and we be inclined towards certain favorite paths.
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As we
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keep using those paths
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again precisely because the snow is pliable and plastic,
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we'll develop tracks and ruts.
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And what we do in our lives
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and what we tend to think that because we're stuck in a rut
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and repeating something
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that not only is the behavior rigid, but the underlying brain is rigid.
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So when I'm working with patients,
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I try not to get fooled by the plastic paradox and
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they're often fooled by the plastic paradox and I would submit
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that
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all of humanity to a large degree has been fooled by the plastic paradox.
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I think we've underestimated
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how plastic our brains really are.
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Doctor Norman Doidge, I want to thank you very much for joining me.
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It's been fascinating and a real pleasure. Thank you.