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( machine beeping )
MAN: Up.
NARRATOR: Graham Young is blind.
YOUNG: You're moving it up and down.
Up.
NARRATOR: Yet he can see.
YOUNG: Down.
NARRATOR: Derek Steen feels pain in an arm that no longer exists.
John Sharon sometimes believes he is God.
SHARON: My attitude was that I was God
and that I had heaven and hell in my eyes.
I was the... the grand guy who created heaven and hell.
NARRATOR: David Silvera is convinced his parents are impostors.
SILVERA: It can look like my father.
It can look identical to him, exactly like him
but it's not him.
NARRATOR: These people are not crazy.
They have all suffered damage in tiny sections of their brains
that has profoundly distorted
the way they perceive themselves and the world around them.
In the past, these bizarre cases
would have been dismissed by science
but today one neuroscientist tracks them down
with the dogged persistence of a detective.
MAN: What excites me
is I can go in there
and pretend I'm Sherlock Holmes and try and figure out
what has gone wrong in this patient's brain--
what's changed that accounts for the strange symptoms.
And this, of course, is a lot of fun to do
because you're learning a lot about the brain;
learning a lot about what causes the symptoms
in that particular patient.
But more importantly, it's telling you
about how the normal human brain works
and how the activity of neurons in the normal brain
gives rise to conscious experience
and gives rise to the whole spectrum of abilities
that we call human nature.
NARRATOR: Can the misfortune of brain injury
shed light on the workings of the normal brain
perhaps even help solve
some of the eternal riddles of human nature?
Understanding the human brain
is one of the ultimate challenges in science.
Watch my two fingers.
Do you see my two fingers?
NARRATOR: Dr. Vilayanur Ramachandran is revolutionizing
our understanding of how the brain works.
His efforts to solve
some of the most baffling neurological mysteries
take him from the hospital bed
to the outer limits of brain science.
RAMACHANDRAN: The human brain is, without any doubt
the most complexly organized form of matter in the universe.
The brain is made up of 100 billion nerve cells, or neurons.
Someone has calculated
that the number of possible permutations and combinations
of brain activity
exceeds the number of elementary particles in the universe.
And this gives you some idea of the staggering complexity
one is faced with in trying to understand
the functions of this mysterious organ.
So, the question is how do you even begin?
NARRATOR: Ramachandran began his investigations
with a strange phenomenon called "phantom limb syndrome."
It's not uncommon for amputees to feel the vivid presence
of a missing limb long after it has gone.
One of Ramachandran's first patients was Derek Steen.
STEEN: 13 years ago, I was involved in a motorcycle accident
and I pulled the nerves out of my spinal cord up in my neck.
They told my parents directly
that I would never use my arm again
About seven years ago I was reading through the classifieds
and I saw an ad in there-- "Amputees Wanted."
I thought it was a joke.
STEEN: It's just basically
connecting the club to the ball.
STEEN: So I called the number and it was Dr. Ramachandran.
NARRATOR: Today, Derek is teaching Ramachandran how to play golf.
But several years ago, Derek made a crucial contribution
to Ramachandran's pioneering work in brain science.
Yes, that was amazing.
STEEN: After my surgery, I sat up in the bed
and still felt the arm there, still felt everything there
and I'm looking down and I'm seeing nothing.
( chuckling ): It was pretty bizarre.
The more I thought about it, the more it hurt.
The more it hurt, the more I thought about it.
So it was... it was, like... it was never-ending.
I mean, I'd break out in a cold sweat and turn pale
just standing here talking to you
because the pain would hit so bad.
If there is any one thing
about our existence that we take for granted
it's the fact that we have a body--
each of us has a body and, you know, you give it a name
it has a bank account, and so on and so forth.
But it turns out even your body
is something that you construct in your mind
and this is what we call your body image.
Now, of course, in my case, it's substantiated by the fact
that I... there really is a body with bone and tissue
but the sense I have, the internal sense I have
of... of the presence of a body and arms and all of that
is, of course, constructed in my brain and it's in my mind.
And the most striking evidence for this
comes from these patients who have had an amputation
and continue to feel the presence of the missing hand.
STEEN: Yay!
NARRATOR: It was the beginning of an important relationship--
important for Derek
because not only would he finally understand
his phantom pain; he would also get to the bottom
of a mysterious sensation he felt while shaving.
STEEN: When I first started shaving
after my surgery
I would feel my absent hand start to hurt and tingle
whenever I shaved this left side of my face.
NARRATOR: Meeting Derek was important for Ramachandran
because the explanation he came up with
would rock the world of neuroscience.
RAMACHANDRAN: How about that?
STEEN: That's just my arm.
NARRATOR: The first thing Ramachandran did
was to invite Derek to his lab for a simple test.
Derek, I'm going to touch
different parts of your body
and I just want you to tell me what you feel
and where you experience the sensation. Okay?
Okay.
Close your eyes.
Could feel that on my forehead.
Anything anywhere else?
No.
Okay.
On my nose.
Okay.
My chest.
Your chest, okay.
I can feel that on my cheek
and I can feel rubbing on the phantom left hand.
On the phantom left hand in addition to your cheek?
I'm going to run the Q-tip across your jaw
and see what happens.
I can feel the Q-tip on my cheek
and I can feel a stroking sensation
across the phantom hand.
You actually feel it stroking across your phantom hand?
Across the palm?
RAMACHANDRAN: So, here is a medical mystery of sorts.
Why does this happen?
Why would a person, when you touch his face
claim that it's also touching his missing phantom fingers?
That's fine.
Palm.
Thumb and palm.
NARRATOR: This was just the kind of mystery
that Ramachandran was drawn to...
although it would take some time to solve.
One day, while Derek was making one-armed repairs
on his favorite Chevy
Ramachandran turned up with his solution.
It was a groundbreaking theory.
RAMACHANDRAN: The reason we think it happens
is that in the brain, there is a complete map
of the surface of the body.
The entire left side of my body, the skin surface
is mapped on to the right side of my brain
along a vertical strip of cortex
which we call the somatosensory cortex.
Similarly, the right side of my body is represented
on the left side of my brain.
So every point on your body surface
has a corresponding point on this body map.
Now, it turns out
that the representation of the face on this map
is right next to the representation of the hand.
Now, that's a bit surprising
as you'd expect the map to be continuous
and faithfully represent the left side of my body.
But it doesn't.
Now, imagine what would happen
if the left arm were amputated.
The part of the brain corresponding to the hand
no longer gets any input
and it's hungry for new sensory input, so to speak.
The sensory signals from the face
normally activate only the face area
that's right next to the hand area.
But they now invade the vacated territory
corresponding to the missing hand
and start activating the hand region in the brain.
And so whatever is reading those signals higher up
misinterprets those signals.
It says those signals are coming from the missing hand
so you experience the sensations
as coming from the missing fingers
even though I'm touching your face.
This is showing there's been a massive reorganization
of the sensory pathways in your brain after the amputation.
And it's as though there's been a cross-wiring in your brain.
Exactly, exactly.
NARRATOR: At first
some members of the neuroscience community
scoffed at Ramachandran's new theory
that neural pathways in the brain can change.
One of the dogmas in neurology has always been
that connections are laid down
in the fetus and in early infancy
and once these connections are laid down
there's nothing you can do to change them.
NARRATOR: As a scientist
Ramachandran knew that such a radical proposal
needed scientific proof.
It was time to give Derek a brain scan.
Hopefully, this would show
what was actually going on in his brain.
But would it prove
that Ramachandran's hunch was correct?
When various parts of Derek's body were wired up
the corresponding activity in his brain
revealed the layout of his body map.
This is a scan of Derek's brain.
The green spot shows the brain's response
to the stimulation of Derek's existing right hand.
Next to it, the red spot shows
that the right side of Derek's face is also being stimulated.
So far, everything is normal.
But in the right hemisphere, the green spot has disappeared
because Derek's missing left arm
can no longer send signals to his brain.
Remarkably, the red area, which corresponds to his left cheek
has now taken over the whole space.
These results vindicated Ramachandran's detective work.
RAMACHANDRAN: It's as though now
the sensory input from the face is innervating
a completely new part of the brain
and this means new pathways have been opened up.
Whether this is because there's been an actual sprouting
of new nerve fibers
or there have been preexisting silent pathways
which are now suddenly active
we are still working on.
We suggested that maybe the connections are already there
like reserve troops ready to be called into action
and when you amputate the hand
these latent connections suddenly become active.
NARRATOR: Phantom sensations do not only occur in the limbs.
RAMACHANDRAN: But in fact, you can get a phantom
with almost any part of the body.
You can get phantom menstrual cramps after a hysterectomy.
You can get phantom appendix pain
even after the appendix has been removed.
Theoretically, you could have a phantom
of almost any part of the body...
except, of course, the brain.
You can't have a phantom brain by definition
because that's where we think it's all happening.
NARRATOR: Luckily for Derek, his phantom pain has subsided.
But that's not always the case.
James Peacock has suffered excruciating pain
since he lost his hand six years ago.
A few days after I woke up, you know--
it might have been under a week
to eight or nine days, something like that--
before the pain really started getting bad, you know
to where it was, like
your hand is just crinched up real tight and stuff
or balled up, you know, and you can't move it.
To unclench it, it's just... you can't.
You can try in your mind...
NARRATOR: This raises a perplexing clinical problem:
How do you treat pain in a body part that's missing?
James tried everything from painkillers to hypnotism
but nothing worked.
Until I found out about the mirror box.
NARRATOR: It was then that he came to see Ramachandran.
One answer might be
that the brain is sending signals to the arm
and trying to clench it.
But in you and me there's messages going back
from the muscles of the hand
telling you you're clenching too much or too fast
and this damps the command signals
so you can slow down.
But the patient has no feedback
because he doesn't have an arm
so the brain says, "Send even more signals," okay?
And this goes on
and you get into a positive feedback loop.
So I said, "Well, if you give him
"some other source of feedback
"such as visual feedback
"maybe that'll trick the brain into thinking
"that the hand is clenching or unclenching
and maybe you can interrupt this loop."
So I said, "Well, why don't we put a mirror there
and, James, look inside the mirror?"
So it's as though you have visually resurrected
the phantom limb.
And, of course, the patient knows it's an illusion
but it's very, very compelling.
PEACOCK: Right now as you look in there and you move your hand
and your phantom does the same thing
as your left hand is doing.
The first time I got in here and I've done this
it was just like it relieved the phantom pain
and unclenched it.
You know, it was just so intriguing, you know.
Sometimes it's just hard to explain how you felt, you know.
NARRATOR: Ramachandran believes the mirror box
needs to be evaluated with many patients
before he can be sure that it really works.
But its undeniable success in uncramping James's phantom hand
suggests that even pain can be a construct of the mind.
The phenomenon of phantom limbs reveals
how our brains can delude us
into being conscious of something that isn't there.
But Ramachandran has come across an even stranger condition--
a remarkable ability of the brain that allows you to see
even though you are totally blind.
This rare condition is called "blindsight."
Ramachandran found Graham Young in Oxford, England.
He is one of the world's few known blindsight patients.
This paradoxical condition shows just how much
our brains run our lives without our being aware of it.
When I was eight, when I had the accident--
it was a road accident that caused the brain damage--
I literally used to walk into lampposts.
I ran into...
you know those huge great pillars you get in stations?
I ran into one of those one day.
NARRATOR: The main visual centers in humans
occupy nearly half the brain
in a large region towards the back of the head.
Graham's vision was devastated by the accident.
Today, he can see to the left
but is blind to everything on the right, in both eyes.
If you put an object in that part of the field
and ask him, "What is it?" he has no idea.
He cannot perceive it consciously.
( machine beeping )
YOUNG: Up.
RAMACHANDRAN: And yet the remarkable thing is
if you move this object
he will tell you which direction it's moving
even though he cannot see the object.
Down... up.
You can see things over here?
YOUNG: Oh, yes.
I'm going to move my hand across.
You tell me when it appears--
when it comes into view.
Now.
Very precisely, as it enters
the seeing part of your field.
If I just hold it over here
and you look there
you can't see anything?
No.
How about now?
You're moving it up and down.
MAN: But you're seeing it?
It's very easy for me to say to you
"Oh, I saw that move up, Colin."
And as soon as I say that
you're going to say, "Ah, he can see!"
No, I can't.
NARRATOR: Colin Blakemore is an Oxford scientist
for whom Graham's mysterious abilities
raise intriguing questions about consciousness.
I think blindsight is extraordinary when you see it.
It's shocking.
I think it's shocking
because it brings home the fact
that we can actually manage our brains without consciousness--
to some extent-- and that leads to...
"Why not everything?"
"Why not everything?"
And why do we need consciousness
for certain things?
What is the extra gloss that consciousness gives--
if anything-- to our actions?
( machine beeping )
YOUNG: Right.
I'm aware of individual functions of sight.
Sometimes I'm aware of a motion
but that motion has no shape, no color, no depth
no form, no contrast.
Sometimes I can tell you what orientation it's at
but then we lose everything else.
BLAKEMORE: So what you lack is
the ability to put it all together
and to recognize an object, a thing?
Yeah.
Something with meaning?
Mmm.
BLAKEMORE: Well, "blindsight" is this term introduced by Larry Weiskrantz
to describe the ability
of people like Graham
to detect things but not to be aware of them;
so very, very different
from what we would normally call vision.
YOUNG: Right.
BLAKEMORE: If there's one thing
that this phenomenon of blindsight teaches us
it is that vision is not entirely seeing--
that there can be a disconnection
from the capacity to respond to visual information
and the actual act of being visually aware of something.
Those two things can be separated
and probably are in our everyday lives
but the problem is that, obviously
we're not aware of the things that we're not aware of.
We just don't know the extent to which they play a part.
RAMACHANDRAN: It's almost as if the patient is using ESP.
He can see and yet cannot see.
So it's a paradox, it's almost like science fiction.
How is this possible?
Well, if you look at the anatomy
you can begin to explain this curious syndrome.
It turns out from the eyeball to the higher centers in the brain
where you interpret the visual image
there's not just one pathway; there are two separate pathways