Oliver Sacks: What Do Hallucinations Reveal About Our Minds? Neurologist Oliver Sacks explains Charles Bonnet syndrome — in which visually impaired people experience lucid hallucinations. He describes the experiences of his patients in detail, and walks through the biology of this underreported phenomenon.
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About 10 years ago an, otherwise perfectly sane woman named Zelda, asked herself a particular question on one particular night. She asked, am I going crazy? That night she was at the theater with her husband, it was a musical, and they were waiting for it to start.

OLIVER SACKS: Zelda is a youthful 70.

RAZ: That's Doctor Oliver Sacks, who wrote about Zelda in his book called "Hallucinations."

SACKS: I am a neurologist of sorts.

RAZ: Probably the most famous neurologist in the world, and Zelda is one of his patients. And when all of Oliver Sacks met her about 10 years ago she told him about this particularly strange night at the theater. The show hadn't started, the curtain was still down, and then suddenly --


RAZ: An explosion of color burst from the curtain --

SACKS: ...Roses.

RAZ: Roses, giant vibrant roses.

SACKS: Apparently throughout the safety curtain and protrude beyond it.

RAZ: So she was looking at a curtain and it began to turn into roses?

SACKS: Yeah, there was a particular — in a particular part of it. She talked about red, green leaves, it's not as if they were painted or two-dimensional — they seemed to thrust into the air towards her. And she had been astonished, staggered, stupefied, amazed, any verb one can use is too mild.

RAZ: So she closes her eyes.

SACKS: And they're still there.

SACKS: She instantly realized it was a hallucination. Her general health was good and her mental health was good. She had never had a hallucination before, had never had any experience remotely similar.

RAZ: And at that moment, in that theater, Zelda asked herself the question, Am I crazy? Am I going crazy? It's the TED radio hour from NPR. I'm Guy Raz and on this episode, that place between madness and sanity. And on the show today, TED speakers who have all asked the same question Zelda asked, Am I going crazy? Now in the case of Zelda, after observing her for a few months, Oliver Sacks figured it out.

SACKS: She has what one would call Charles Bonnet syndrome.

RAZ: Charles Bonnet syndrome, it's named after Swiss botanist named Charles Bonnet, and Oliver Sacks described it in his TED talk.

SACKS: Charles Bonnet did not have them, his grandfather had these hallucinations, and in 1759, he described to his grandson various things he was seeing. So on one occasion, when his granddaughters were visiting him, he said, And who are these handsome young men with you? And they said, Alas grandpapa, there are no handsome young men, and then the handsome young men disappeared. It's typical of these hallucinations that they may come in a flash and disappear in a flash. On one occasion he saw a man in a bathrobe smoking a pipe, and realized it was himself. That was the only figure he recognized. And on one occasion, when he was walking in the streets of Paris he saw — this was real — a scaffolding, but when he got back home he saw a miniature of the scaffolding six inches high on his study table.

RAZ: Charles Bonnet told his grandfather to keep a journal of all those hallucinations, and so, 250 years later, Zelda did the same thing.


SACKS: She said it had astonished her to find that she had many hallucinations every day.

RAZ: What did she see?

SACKS: Well, there was a very wide range. Sometimes she saw simple geometrical patterns. Surfaces, walls, would be covered with patterns like this. People's faces would occasionally change for her. I think on one occasion the postman seemed to become gargoyle-like.

RAZ: And then when she was driving she'd also see things.

SACKS: A boy appeared on the hood of the car, almost naked, pivoting, I think as if he were about to throw a discus or something like this. Her husband tried to shake the hallucination off, but the boy was there very tenaciously, but when they came to a parking lot, she said he rose up and disappeared.

RAZ: Charles Bonnet identified the condition, but he wasn't sure why it was happening. And it would take scientists another 150 years before they understood the reasons behind it. When you gave your TED talk, you had a line in there that struck me. You said, As a physician, I have to try and define what's going on, and to reassure people...

SACKS: ...especially to reassure them that they're not going insane. In particular, the notion is that if you see things or hear things you're going mad. But the psychotic hallucinations are quite different. Psychotic hallucinations, whether they're visual or vocal, they address you.


SACKS: They accuse you, they seduce you, they humiliate you, they jeer at you. There is none of this quality of being addressed with the Charles Bonnet hallucinations. You're seeing a film which had nothing to do with you. So, what is going on? Fascinatingly, in the last few years it's been possible to do functional brain imagery, to do fMRI on people as they are hallucinating. And in fact to find that different parts of the visual brain are activated as they're hallucinating. When images are formed, a higher part of the visual cortex is involved in the temporal lobe. And in particular, one area of the temporal lobe is called the fusiform gyrus, and it's known that if people have damage in the fusiform gyrus, they may lose the ability to recognize faces. But if there's an abnormal activity in the fusiform gyrus, they may hallucinate faces. And around 1970 it was found that there were not only parts of the brain but particular cells — face cells were discovered around 1970. And now we know that there are hundreds of other sorts of cells which can be very, very specific. So you may not only have car cells, you may have Aston Martin cells...


SACKS: ...I saw an Aston Martin this morning...I had to bring it in. And now it's in there somewhere. So there is another part of the brain which is especially activated when one sees cartoons. It's activated when one recognizes cartoons, when one draws cartoons, and when one hallucinates them. It's very interesting that that should be specific. There are other parts of the brain which are specifically involved with the recognition and hallucination of buildings and landscapes. Now at this level in what's called the inferotemporal cortex there are only visual images of figments or fragments. It's only at higher levels that the other senses join in and there are connections with memory and emotion. And in that Charles Bonnet syndrome you don't go to those higher levels. You are on these levels of inferior visual cortex where you have thousands and tens of thousands and millions of images or figments or fragments of figments all neurally encoded in particular cells or small clusters of cells. So suddenly you see a face, suddenly you see a car, suddenly this and suddenly that. The mind does his best to organize and to give some sort of coherence to this, but not terribly successfully. Charles Bonnet said 250 years ago he wondered how thinking of these hallucinations how as he put it the theater of the mind could be generated by the machinery of the brain. Now 250 years later, I think we're beginning to glimpse how this is done. Thanks very much.


RAZ: At a certain point we all ask ourselves, am I going crazy? Am I going mad?


RAZ: Happens to everybody.

SACKS: I know vividly when it happened with me. It was in the 1960's and I suddenly started hallucinating. I ran for a bus and on the bus the people opposite me seemed to have huge egg shaped heads rather like Humpty Dumpty heads with faceted insect-like eyes, which seemed to move suddenly. I was aware that this was a hallucination and a severe one, and one I hadn't ordered, one which bewildered me. I was very, very frightened. I think perhaps more frightened by a loss of control. I was fighting for control and one form of doing that was to write, and as it were to try and somehow become a reporter of my condition rather than totally immersed in it. I wanted to keep a level of critical consciousness from being drowned.

RAZ: I was listening to a TED talk by Elyn Saks who's schizophrenic. And by the way, she'll be on the show as well. And in her talk she quotes the poet writer Maria Rilke who had met Freud, and Freud offered him psychoanalysis and then Rilke says, no thanks. Do you know the quote?

SACKS: Yeah, I do know the quote.

RAZ: "Don't take my devils away because my angels may flee too."

SACKS: Yes, Freud was approached by a number of highly creative people with some mad sounding symptoms. And basically he said, I think you can live with these and you may need to. I don't know how metaphoric or real Rilke's angels or devils were, but one may need some of one's devils and angels.

RAZ: There are truly insane people. I mean, are we in some ways, all of us in the kind of a gray area between that extreme and the other extreme of having no delusions or illusions or madness?

SACKS: Freud brought this out, for example, when he spoke about common unhappiness. He agreed that there was a horrible and dangerous thing, which was depression or melancholia, which might lead to suicide and might ruin a life, but he felt that unhappiness as such was a feature of life. And that one had to endure as well as enjoy and people who don't may seem to be too shallow on the surface of life. People need depth and depth means the possibility of unhappiness and frustration and sometimes torment. Though hopefully not madness.

RAZ: Neurologist Oliver Sacks. His latest book is called, "Hallucinations."

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