Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
Transcripts

"Secrets of the Mind"

PBS Airdate: October 23, 2001
Go to the companion Web site

NARRATOR: Graham Young is blind...

GRAHAM YOUNG: You're moving it up and down.

NARRATOR: ...yet he can see.

Derek Steen feels pain in an arm that no longer exists.

John Sharon sometimes believes he is God.

JOHN SHARON: My attitude was I was God and then I had heaven and hell in my eyes. I was the grand guy who created heaven and hell.

NARRATOR: David Silvera is convinced his parents are imposters.

DAVID 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.

V.S. RAMACHANDRAN (University of California, San Diego): 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.

Major funding for NOVA is provided by the Park Foundation, dedicated to education and quality television.

This program is funded in part by the Northwestern Mutual Foundation. Some people already know Northwestern Mutual can help plan for your children's education. Are you there yet? Northwestern Mutual Financial Network.

Scientific achievement is fueled by the simple desire to make things clear. Sprint PCS is proud to support NOVA.

And by the Corporation for Public Broadcasting, and by contributions to your PBS station from viewers like you. Thank you.

NARRATOR: Dr. Vilanyur 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.

V.S. 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.

DEREK STEEN: Thirteen 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. So I called the number and it was Dr. Ramachandran.

It's basically connecting the club to the ball.

NARRATOR: Today, Derek is teaching Ramachandran how to play golf...

DEREK STEEN: Beautiful. Whoa.

NARRATOR: ...but several years ago, Derek made a crucial contribution to Ramachandran's pioneering work in brain science.

DEREK 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. It was pretty bizarre. The more I thought about it, the more it hurt. The more it hurt, the more I thought about it. And so it was neverending. 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.

V.S. RAMACHANDRAN: If there is one thing about our existence that we take for granted, it's the fact that we have a body. Each of has a body and 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 there really is a body with bone and tissue. But the sense I have—the internal sense I have—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.

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 had while shaving.

DEREK 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.

The first thing Ramachandran did was to invite Derek to his lab for a simple test.

V.S. RAMACHANDRAN: 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? Close your eyes.

DEREK STEEN: I did feel that on my forehead.

V.S. RAMACHANDRAN: Anything anywhere else?

DEREK STEEN: No...on my nose.

V.S. RAMACHANDRAN: Okay.

DEREK STEEN: On my chest.

V.S. RAMACHANDRAN: On your chest? Okay.

DEREK STEEN: I can feel that on my cheek and I can feel rubbing on the phantom left hand.

V.S. RAMACHANDRAN: 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.

DEREK STEEN: I can feel the Q-tip on my cheek and I can feel a stroking sensation across the phantom hand.

V.S. RAMACHANDRAN: You actually feel it stroking across your phantom hand?

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?

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.

V.S. 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 of 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.

DEREK STEEN: 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.

V.S. RAMACHANDRAN: One of the dogmas in neurology has always been that connections are laid down in the fetus 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 right 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.

V.S. 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 pre-existing silent pathways, which are now suddenly active, we're 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.

V.S. 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 can 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.

JAMES PEACOCK: 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, and balled up, you know? And you can't move it. To unclinch it's just...you can't. You 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.

JAMES PEACOCK: Until I found out about the mirror box.

NARRATOR: It was then he came to see Ramachandran.

V.S. 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 sort of 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 have James look inside the mirror?" It's just 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.

JAMES PEACOCK: Right. Now as you look in there and you move your hand, your phantom does the same thing as your left hand is doing. The first time I got in here and I'd 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.

GRAHAM YOUNG: 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 lamp posts. I ran into, you know, these 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.

V.S. RAMACHANDRAN: 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.

GRAHAM YOUNG: Up.

V.S. RAMACHANDRAN: And yet the remarkable thing is if you move this object, he will tell which direction it's moving...

GRAHAM YOUNG: Down. Up.

V.S. RAMACHANDRAN: ...even though he cannot see the object.

GRAHAM YOUNG: Up.

COLIN BLAKEMORE (Oxford University): You can see things over here?

GRAHAM YOUNG: Oh, yes. I can see.

COLIN BLAKEMORE: I'm going to move my hand across. You tell me when it appears...when it comes into view.

GRAHAM YOUNG: Now.

COLIN BLAKEMORE: 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?

GRAHAM YOUNG: No.

COLIN BLAKEMORE: How about now?

GRAHAM YOUNG: You're moving it up and down.

COLIN BLAKEMORE: But you're seeing it!

GRAHAM YOUNG: 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.

COLIN BLAKEMORE: 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 the question, "Well then...

V.S. RAMACHANDRAN: "Why not everything?"

COLIN BLAKEMORE: "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?

GRAHAM YOUNG: Right. I'm aware of individual functions of sight. Sometimes I am 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.

COLIN BLAKEMORE: So what you lack is the ability to put it all together, and to recognize an object, a thing, something with meaning. 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.

GRAHAM YOUNG: Right.

COLIN 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.

V.S. 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 of the brain where you interpret the visual image, there's not just one pathway. There are two separate pathways, which subserve different aspects of vision. One of these pathways is the evolutionarily new pathway, the more sophisticated pathway, if you like, that goes from the eyeball through the thalamus to the visual cortex of the brain. Now, you need the visual cortex for consciously seeing something. The other pathway, which is older evolutionarily, and is more prominent in animals like rodents, lower mammals, birds and reptiles, goes to the brain stem, the stalk on which the brain sits. And, from the brain stem, gets relayed eventually to the higher centers of the brain. Specifically, the older pathway going through the brain stem is concerned with reflexive behavior orienting to something important in the visual field, making eye movements, directing your gaze, directing your head toward something important.

In these patients, one of these pathways alone is damaged—the visual cortex is damaged. Because that's gone, the patient doesn't see anything consciously. But the other pathway is still intact. And he can use that pathway to guess correctly the direction of movement of an object that he cannot see.

NARRATOR: Graham's vision is similar to that of reptiles who depend on unconscious blindsight for their survival.

GRAHAM YOUNG: A lizard, if it wants to catch a fly, for example, it doesn't actually have to see a fly. It doesn't have to recognize a fly. It just has to be aware of something moving. So I suppose me and the lizard are distant cousins.

V.S. RAMACHANDRAN: One of the goals of neuroscience is to understand which parts of the brain are dedicated to what function—how different mental capacities map onto different pathways and different neurocircuits in the brain. And surely this fascinating syndrome is going to help us understand not only the nature of seeing, not only the division of labor between these different pathways, but the question of, "What is consciousness? What does it mean to be consciously aware of something? Why is one pathway alone conscious but does the other pathway behave like a zombie that's trapped inside him, that's unconscious? The syndrome is so strange that when it was initially reported people didn't believe it, and there are some people who still don't believe it. But in a sense it's not that strange if you think about it, because in a sense we experience blindsight all the time in our daily lives. For example, as I am driving this car and having this conversation, all my attention is on the conversation...on the person next to me. And, in fact, I'm not conscious of what's going on around me even though I'm negotiating all this traffic, avoiding obstacles, avoiding that car on my right, avoiding the car on my left. That's all being done in parallel by another part of my brain and it never emerges into conscious awareness unless something very strange happens like a big truck passes by and I might notice it.

NARRATOR: Blindsight enables us to steer our way successfully through the world as if on autopilot. Without this zombie in our brains, we'd be swamped by visual information, unable to focus on what really matters.

Unlike Graham, Peggy Palmer has normal vision. She should be able to copy this star easily.

PEGGY PALMER: I'll never get this star. I'm hopeless at this.

NARRATOR: But something odd is happening. One whole side of the star is missing. Peggy has a condition called "visual neglect." Although her eyesight is fine, half of her visual world no longer seems to matter. Ten years ago, Peggy suffered a stroke in the parietal lobes of her brain.

V.S. RAMACHANDRAN: The parietal lobes are concerned mainly with creating a three dimensional representation of the spatial layout of the world, allowing a person to walk around, to navigate, to avoid bumping into things. When the right parietal is damaged the patient is unable to deal with the left side of the world.

NARRATOR: This condition has fascinated neurologists for more than a century, because it reveals not only how the brain shapes the way we perceive space in the present, it even determines the spatial look of our memories. This became apparent when Peggy was asked to draw a daisy from memory.

For neuropsychologist, Peter Halligan, Peggy's drawings reveal exactly what's gone wrong.

PETER HALLIGAN (University of Wales): It's like a radar system whereby the actual radar system on the left-hand side is no longer working well. If someone comes in on my left-hand side now, or I hear a sound, my eyes will immediately move to the left-hand side. That makes me, for evolutionary purposes, very aware of my environment, because if I wasn't aware of those things, I'd have accidents. I'd get hurt or I might get eaten by wild animals and whatever. Now in Peggy's case, she will not attend to those things that we would normally be aware of.

NARRATOR: Peggy thinks she's drawn her daisies right until it's pointed out to her.

PETER HALLIGAN: You've noticed that, have you?

PEGGY PALMER: Oh, dear!

PETER HALLIGAN: So what Peggy's drawn for us is several nice daisies with the left side missing—the same with this one and this one. And look at this one. This is a very good example.

PEGGY PALMER: I've done it on all of them.

V.S. RAMACHANDRAN: Which means that she's not only neglecting events in the world, but when she conjures up a mental image, she's ignoring the left side of that mental image.

PEGGY PALMER: I thought I was going all the way 'round, you see.

V.S. RAMACHANDRAN: And this shows you that it is not simply a sensory problem but a problem of consciousness.

PEGGY PALMER: It's because I'm so concentrating on that side. It takes everything away, you see. It's attention really. It's taken away. There must be two attentions somewhere in your body that one side's taking the other one away. I can't make it out at all—very odd.

NARRATOR: Peggy's one-sided daisies graphically reveal how damage to the visual centers can warp our consciousness of the world and how complex the human visual system actually is.

V.S. RAMACHANDRAN: When I was a medical student I was taught there is an area in the back of the brain called visual cortex and that's where seeing takes place. But since then we've learned, in fact, there is not just one. There are thirty areas in the brain concerned just with seeing.

NARRATOR: For Ramachandran, a walk through this Southern California mall shows exactly what these visual areas have evolved for.

V.S. RAMACHANDRAN: And maybe these different areas are specialized for different aspects of vision. One area for seeing colors, another area for seeing movement, or form and shape, relative distance and depth. Now, despite this staggering complexity of all these different areas, there seems to be a simple overall pattern of organization. In fact, the visual input, as it comes in, seems to divide into two parallel streams of processing. There is one pathway which we call the "how" pathway, to which some of these areas belong. And that "how" pathway seems to be concerned mainly with navigation—with being able to walk around...avoid bumping into obstacles...avoiding uneven terrain, reaching out and grabbing something.

NARRATOR: The "how" pathway leads from the main visual areas to the parietal lobes at the top of the brain, where Peggy suffered her stroke. The other pathway, the "what" pathway, leads from the main visual areas to the temporal lobes located just behind our temples.

V.S. RAMACHANDRAN: The "what" pathway is concerned with recognizing the object. "What am I looking at? What does it mean for me? Is this an edible object? Is it a flower? Is it a person's face? What is it that I'm looking at, and what does it mean for me?" That's what the "what" pathway is concerned with, and it's that pathway that seems to be damaged in David.

NARRATOR: David presented Ramachandran with one of the strangest cases he has ever encountered.

Two years ago David was involved in a terrible car accident while driving back to California from Mexico.

DAVID SILVERA: There was a problem with the car and I landed in the highway with my head first.

NARRATOR: For five weeks David lay in a coma. Serious injuries led to the loss of his right arm, but to everyone's relief, when he regained consciousness his mental capacities seemed to be intact.

V.S. RAMACHANDRAN: He was articulate, he was intelligent, not obviously psychotic or emotionally disturbed. He could read a newspaper. Everything seemed fine except he had one profound delusion. He would look at his mother and he would say, "This woman, Doctor, she looks exactly like my mother but in fact she's not my mother. She's an imposter. She's some other woman pretending to be my mother."

NARRATOR: The injury to David's brain had brought on a very rare condition called the Capgras Delusion.

ROSITA SILVERA: I was cooking dinner and he probably didn't like the food that night and he said, "You know, that lady who comes in the morning she cooks much better than you." He'd say, "It's that lady. I like that lady very much." But the lady was me of course, all the time.

NARRATOR: David was also convinced that his father was an impostor.

ROSITA SILVERA: He would say to his dad, "You know I'm sure you would like to meet this guy. He's so much like you, but he drives better. He doesn't go so fast."

DAVID SILVERA: It can look identical to him, exactly like him, but it's not him.

NARRATOR: After two months of this disturbing behavior, David's parents decided to seek help from Ramachandran.

V.S. RAMACHANDRAN: But when you looked at the person who looked like your father, what was your feeling? Did it look like there's some other person who resembles your father who's not really your father? Something like that?

DAVID SILVERA: Exactly. It's the difference in the fact that I know that that person happens not to be my father.

V.S. RAMACHANDRAN: Uh huh.

DAVID SILVERA: It is not my father or my mother, right? I don't expect things from that person as I would expect from my parents.

NARRATOR: David not only had delusions about people, he also believed that the house that he lived in was just an imitation of his home.

ROSITA SILVERA: One day he started getting really angry: "I want to go to my house, I want to go to David's house. I want to go to David's house." And we were in the apartment and I'm just going, "What am I going to do?" So I decided. I said, "Okay, David. Let's go." So I took him down the stairs and I went around through the back, came back through the elevator, took him to the same apartment, and I said, "This is your house." And I opened the door, and I said, "Okay. Ciao," and just left him there alone. It was the same apartment. And he looked at it and said, "Oh, yes, this is my apartment." Things like that would happen, then maybe a few days after he would start saying, "I want to go to my house, David's house. This is not David's house."

NARRATOR: Amazingly David sometimes referred to himself as the other David, as if his own self were an impostor.

V.S. RAMACHANDRAN: The Capgras Delusion has been known since the turn of the century but has been treated as a curiosity, an anomaly. The standard explanation, which you find in most psychiatry textbooks, is a Freudian one and the idea is something like this: this young man, like most young people, when he was an infant...growing up, he had strong sexual attraction to his mother, the so-called "Freudian Oedipus complex." But then along comes a blow to the head, and suddenly and inexplicably these sexual urges come flaming to the surface, and he finds himself sexually attracted to his mother. And he says, "My God, if this is my mother how come I'm attracted to her? How come I'm aroused? This must be some other strange woman."

Now this is an ingenious explanation but it doesn't quite work, because I've seen a patient who has the same delusion about his pet dog. He'll look at his pet dog and say, "Doctor, this is not Fifi. It looks just like Fifi, but in fact it's been replaced by another identical dog." So how does a Freudian explanation account for this, unless you start talking about the inherent bestiality in all human beings or something like that? So what really causes the Capgras Delusion? Well, it turns out that when you look at an object the message goes to the temporal lobes—to the visual centers in the temporal lobes—but seeing is a multi-level process. After you've recognized it, you also need to respond to the object emotionally. This is obvious when you look at a Picasso or a Rembrandt or any beautiful picture. Even when you look at, say, your mother's face the appropriate emotional warmth has to be evoked. Or when you look at a lion you have to be afraid. And all of this is part of the visual process, but happening in a different part of the brain.

NARRATOR: Whenever we look at an object or a face, the message reaches the temporal lobes, where it's identified, but then it gets relayed to a structure called the "amygdala," which is the gateway to the limbic system that contains the emotional centers of the brain. And it's here that we generate the appropriate emotional response to whatever it is we're looking at.

V.S. RAMACHANDRAN: Now, what I've suggested is that what's going on in this patient is the message gets to the temporal lobe cortex, so the patient recognizes his mother as being his mother and evokes the appropriate memories. But the message doesn't get to the amygdala, because the fibers going from the temporal cortex to the amygdala into the emotional centers are cut, as a result of the accident. Therefore, there is no emotion. There is no warmth. And he says, "If this is really my mother why is it I'm not experiencing any emotions? There's something not quite right here. Maybe she is some other strange woman pretending to be my mother."

NARRATOR: Ramachandran's hunch that David's delusions were being caused by the rupture of specific brain circuits was lent unexpected weight when David's mother recalled a breakthrough with the phone.

ROSITA SILVERA: We got so tired of him saying, "You're not my dad; you're my dad. You're not my mother; you're my mother." We decided, "Okay, you go downstairs, call on the phone and say, 'David? Hi!'" And on the phone he would know he was his dad. On the phone he never ever...

V.S. RAMACHANDRAN: ...had this problem.

ROSITA SILVERA: ...had this problem!

V.S. RAMACHANDRAN: So on the phone he'd always recognize...

ROSITA SILVERA: On the phone...

V.S. RAMACHANDRAN: ...as his father?

ROSITA SILVERA: ...as his father. No problem.

V.S. RAMACHANDRAN: But when he saw him in person he would say, "You look like my father, but you're not really my..."

ROSITA SILVERA: "...but you're not my father. No."

V.S. RAMACHANDRAN: This shows the patient is not crazy. Why would he be crazy in person but not on the phone? The answer is there's a separate pathway that goes from the auditory cortex—the hearing part of the temporal lobe—to the amygdala, and that pathway was not damaged in David by the car accident. Therefore, when he listens to his father on the phone there is no delusion. This is a lovely example of how you can take a completely bizarre neurological syndrome—maybe from the X-Files of neurology—which no one really understood: a person claiming that his mother is an impostor; and then come up with a very detailed explanation in terms of the known anatomy of the brain, saying, "Here is where the flaw is," and then doing an experiment that takes just an hour to do and showing that this is what's gone wrong in this patient.

TECHNICIAN: You comfortable?

NARRATOR: To test his theory about the Capgras Delusion, Ramachandran arranges to measure David's galvanic skin response, which is the basis of the lie detector test. If David's brain were normal, he would react emotionally to this picture of his father. This in turn would stimulate an almost indiscernible increase of sweat on his skin and a heightening of electrical resistance that can be measured.

The prediction is that when people with normal brains look at photographs of people they don't know, they will not respond emotionally, so there will be no change in skin resistance. But a familiar face will prompt an emotional response and invariably there is a change.

Now the question is, "What happens with David?"

If Ramachandran's theory is correct pictures of his parents will not evoke an emotional response so the line should remain flat.

V.S. RAMACHANDRAN: Now, this is also telling you about how all of us—normal people—respond to faces and to objects, because what happens in this patient is truly extraordinary. The lack of emotional response actually leads him to this very profound delusion that this person is not really his mother. In other words, the lack of the autonomic gut reaction, this emotional response leads him to an absurd conclusion, overriding what his intellect is telling him. And this tells you how closely linked your intellectual view of the world is to your basic emotional reactions to the world.

NARRATOR: Luckily for Capgras patients, the condition seems to heal itself. David no longer thinks his mother is an impostor. And the man who looks like his father is his father and triggers the flow of all the old familiar feelings.

David's lack of emotional response showed just how crucial emotions are to the recognition process of the normal brain. But what would happen if the emotions were to run out of control? What effect might an excess of emotion have on the way we interpret the world?

John Sharon has temporal lobe epilepsy.

JOHN SHARON: The seizures involve my person and my soul and my spirit, all of it. When I get one of those feelings my whole body just tingles and I just, oh...that's that.

NARRATOR: John's epileptic seizures are essentially an electrical storm in his temporal lobes when a group of neurons starts firing at random, out of sync with rest of his brain.

Recently John experienced one of his worst episodes to date. He'd gone out to the desert with a girlfriend, and they'd both got very drunk, with disastrous results. John was suddenly hit by a volley of seizures, each one lasted about five minutes and involved violent convulsions that left him unconscious. Eventually, John managed to get a call through to his father who drove out to the desert to bring him home.

JOHN SHARON: On the way home, him and I got just into some philosophical questions about everything. And I just would not shut up once I...on the way home I was going and going. It was like I was wired.

JOHN SHARON, SR.: It's basically an earthquake within the body, and like any earthquake there are aftershocks. And like any earthquake that does damage, things have to be rebuilt. Things have to subside. Mainly what I deal with is the aftermath, particularly with this last episode. It was very much like stepping into a Salvador Dali painting. Instantly everything was surreal. And that's, in essence, what his seizures are all about—the aftermath—where it puts his brain, where it puts his memory, where it puts his mind, his thinking ability, everything else.

NARRATOR: When John's seizures came to an end he was exhausted but he felt omnipotent.

JOHN SHARON: I went running down the streets screaming that I was God. And then this guy came out and I just, like, pelvic thrust at him and his wife, and I was like, "You want to f—ing bet, I ain't God?"

JOHN SHARON SR.: And I said, literally, "You asshole, get back in here! What do you think you're doing? You're disturbing the neighbors. They're gonna call the cops. What is this all about?"

JOHN SHARON: I kind of just looked at him, cool and calm, and apologized to him, and like, "No. No one's going to call the police." Like, I didn't say this last part, but I'm thinking to myself, "No one's going to call the police on God!"

NARRATOR: John had never been religious, yet the onset of his seizures brought on overwhelming spiritual feelings.

V.S. RAMACHANDRAN: It has been known for a long time that some patients with seizures originating in the temporal lobes have intense religious auras, intense experience of God visiting them. Sometimes it's a personal god, sometimes it's a more diffuse feeling of being one with the cosmos. Everything seems suffused with meaning. The patient will say, "Finally I see what it's really about, Doctor. I really understand God. I understand my place in the universe, in the cosmic scheme." Why does this happen and why does it happen so often in patients with temporal lobe seizures?

NARRATOR: Ramachandran met John shortly after the episode in the desert. He was still feeling the extreme highs and lows that follow his seizures. Ramachandran was about to witness the emotional intensity that John endures.

JOHN SHARON: I have been in so much pain that I'd rather be shot to death, whipped to death...

V.S. RAMACHANDRAN: Also joy?

JOHN SHARON: Yes. I've been in so much joy that I would rather be left alone, man. Take everything away and just let me sit there and have that much joy. I feel like I can float and stuff sometimes, you know?

V.S. RAMACHANDRAN: Okay.

JOHN SHARON: It's, like, the best.

JOHN SHARON, SR.: There were times where we would have seven or eight grand mal seizures in a day. He would never come back to this reality during that time. I have looked in his eyes in those times and I have seen...seen a cry for help.

JOHN SHARON: No, I mean, you guys, that's the thing, though. A lot of other people can just walk around and see the beauty of the world. I can...sorry. It's not as beautiful.

JOHN SHARON, SR.: He has a seizure, he'll want to talk philosophy. He'll want to discuss all the things that are floating around in the stew he's got up here that he's trying to reconstruct. Thoughts that he may have had just floating through his mind while he was in a seizure mode may come surfacing.

V.S. RAMACHANDRAN: I see. Okay. But also you said he's become more emotional because of the seizures, so that's helpful, too.

JOHN SHARON, SR: Mmm, much more sensitive. But oddly enough, not in regards to himself...

V.S. RAMACHANDRAN: Okay.

JOHN SHARON, SR.: ...but in regards to atrocities, disasters, things like that...anywhere and everywhere...wrongs done to other people.

JOHN SHARON: Oh my God. And you know what? I am so right in my own head, I know I could go out there and get people to follow me. Not like these whackos with sheets on their heads, not like those idiots...but now it's just the new generation of the prophets. And were all the prophets people who were flopping around on the ground, is that what this whole message was, the gift from the gods, this whole time?

V.S. RAMACHANDRAN: That's possible, isn't it? Yes?

JOHN SHARON: I've never been religious, ever. People say, "No, you can't see into the future...unh unh." That's what that gift is, but you've got to pay for it by getting slammed around.

V.S. RAMACHANDRAN: Now, why do these patients have intense religious experiences when they have these seizures? And why do they become preoccupied with theological and religious matters even in between seizures?

One possibility is that the seizure activity in the temporal lobes somehow creates all kinds of odd, strange emotions in the person's mind...in the person's brain. And this welling up of bizarre emotions may be interpreted by the patient as visits from another world, or as, "God is visiting me." Maybe that's the only way he can make sense of this welter of strange emotions going on in his brain. Another possibility is that this is something to do with the way in which the temporal lobes are wired up to deal with the world emotionally. As we walk around and interact with the world, you need some way of determining what's important, what's emotionally salient and what's relevant to you versus something trivial and unimportant.

How does this come about? We think what's critical is the connection between the sensory areas in the temporal lobes and the amygdala, which is the gateway to the emotional centers in the brain. The strength of these connections is what determines how emotionally salient something is. And therefore, you could speak of a sort of emotional salience landscape, with hills and valleys corresponding to what's important and what's not important. And each of us has a slightly different emotional salience landscape. Now, consider what happens in temporal lobe epilepsy when you have repeated seizures. What might be going on is an indiscriminate strengthening of all these pathways. It's a bit like water flowing down rivulets along the cliff surface. When it rains repeatedly there's an increasing tendency for the water to make furrows along one pathway and this progressive deepening of the furrows artificially raises the emotional significance of some categories of inputs. So instead of just finding lions and tigers and mothers emotionally salient, he finds everything deeply salient. For example, a grain of sand, a piece of driftwood, seaweed, all of this becomes imbued with deep significance. Now, this tendency to ascribe cosmic significance to everything around you might be akin to what we call a mystical experience or a religious experience.

NARRATOR: For Ramachandran, John's story is the basis of one of his most intriguing and controversial theories. Could there be a specialized area of the brain that drives human beings to seek religion?

V.S. RAMACHANDRAN: A few years ago, the popular press inaccurately quoted me as having claimed that there is a God center or a "G-spot" in the temporal lobes. Now, this is complete nonsense. There is no specific area in the temporal lobe concerned with God. But it's possible there are parts of the temporal lobes whose activity is somehow conducive to religious belief. Now this seems unlikely, but it might be true. Now, why might we have neural machinery in the temporal lobes for belief in religion? Well belief in religion is widespread. Every tribe, every society has some form of religious worship. And maybe the reason it evolved, if it did evolve, is that it is conducive to the stability of society, and this may be easiest if you believe in some sort of supreme being. And that may be one reason why religious sentiments evolved in the brain.

JOHN SHARON: The only reason I probably would get rid of the seizures and epilepsy, because I've never even seen them, is because of my family, because of him. I would keep them for those visions, because of the way I see the world falling into place and things like that. It's a wild little place to be stuck in there. It also seems like a key and right now I haven't learned how to get to the key without...use the key without those seizures. If I was told that I would never have a chance to have that key again, sorry, I'm going to hold on to that thing.

V.S. RAMACHANDRAN: Just because some patients with temporal lobe seizures have intense religious experiences, this does not in any way invalidate that experience for that patient. In fact, it can very often enrich the patient's life enormously. And it poses a dilemma very often for the physician, because what right do we have to treat the patient with medication or with surgery, thereby, in some instances, depriving him of these valuable experiences? To me the exciting thing is that subjects like God and religion can now be actually addressed by us scientists. We can begin to ask questions about religion and God and begin to approach these questions by listening to these patients—by talking with them and by studying them.

NARRATOR: It is a tragic irony that today's breakthroughs in our understanding of the human brain are made possible by the misfortune of brain injury. For centuries, philosophers have labored to understand God, consciousness and the mysteries of human nature. Now perhaps science will have its chance.

On NOVA's Website, investigate the remarkable complexity of the mind, through other unusual case studies collected by Dr. Ramachandran, on PBS.org or AOL, Keyword PBS.

To order this show or any other NOVA program, for $19.95, plus shipping and handling, call WGBH Boston Video at 1-800-255-9424.

Next time, on NOVA, "The doctor said that there had been an accident." "We can impose a gender identify on a newborn." "He did not say that it was an experiment." "I was never happy as Brenda, never." Sex Unknown.

NOVA is a production of WGBH Boston.

Major funding for NOVA is provided by the Park Foundation, dedicated to education and quality television.

Scientific achievement is fueled by the simple desire to make things clear. Sprint PCS is proud to support NOVA.

This program is funded in part by the Northwestern Mutual Foundation. Some people already know Northwestern Mutual can help plan for your children's education. Are you there yet? Northwestern Mutual Financial Network.

And by the Corporation for Public Broadcasting, and by contributions to your PBS station from viewers like you. Thank you.

Q-Tips® is a registered trademark of Chesebrough-Ponds, Inc.



PRODUCTION CREDITS

Secrets of the Mind

Written and Directed by
Christopher Rawlence

Produced by
Emma Crichton-Miller

Narrated by
Rena Baskin

Associate Producer
Barbara Park

Edited by
Rod McClean

Consulting Producer
Nancy Linde

Music
Simon Whiteside

Camera
Chris Morphet

Sound Recordist
Greg Bailey

Graphics
Penny Holton
Skaramoosh

Production Accountant
Caroline Gaukroger

Production Managers
Gina Marsh
Denise Lesley

Online Editor
Richard Craddock

Dubbing Mixer
Damian Reynolds

Production Assistant
Martine Coker

Special Thanks
Professor Laurence Weiskrantz, Oxford University
Dr. Lance Stone, San Diego Rehabilitation Institute
Professor John Marshall, Oxford University
Professor Haydn Ellis, University of Wales

NOVA Series Graphics
National Ministry of Design

NOVA Theme
Mason Daring
Martin Brody
Michael Whalen

Post Production Online Editor
Mark Steele

Closed Captioning
The Caption Center

Production Secretaries
Queene Coyne
Linda Callahan

Publicity
Jonathan Renes
Diane Buxton
Katie Kemple

Senior Researcher
Ethan Herberman

Unit Managers
Sarah Goldman
Jessica Maher
Sharon Winsett

Paralegal
Nancy Marshall

Legal Counsel
Susan Rosen Shishko

Business Manager
Laurie Cahalane

Post Production Assistant
Patrick Carey

Associate Producer, Post Production
Nathan Gunner

Post Production Supervisor
Regina O'Toole

Post Production Editors
David Eells
Rebecca Nieto

Supervising Producer
Lisa D'Angelo

Senior Science Editor
Evan Hadingham

Senior Series Producer
Melanie Wallace

Managing Director
Alan Ritsko

Executive Producer
Paula S. Apsell

A Rosetta Pictures production for NOVA/WGBH and Channel 4.

© 2001 WGBH Educational Foundation

All rights reserved

 

About NOVA | NOVA Homepage | Support NOVA

© | Created September 2006

Support provided by

For new content
visit the redesigned
NOVA site