Neurologist Oliver Sacks, who died Sunday, once described himself as an "old Jewish atheist," but during the decades he spent studying the human brain, he sometimes found himself recording experiences that he likened to a godly cosmic force.

Such was the case once when Sacks tried marijuana in the 1960s: He was looking at his hand, and it appeared to be retreating from him, yet getting larger and larger.

"I was fascinated that one could have such perceptual changes, and also that they went with a certain feeling of significance, an almost numinous feeling," Sacks told Fresh Air's Terry Gross in 2012. "I'm strongly atheist by disposition, but nonetheless when this happened, I couldn't help thinking, 'That must be what the hand of God is like.' "

Sacks was the author of numerous books that examined the mysteries of perception, memory and consciousness. Often his books described patients with unusual neurological disorders and brain injuries — such as The Man Who Mistook His Wife for a Hat.

Sacks' 1973 book Awakenings, which was adapted into a film starring Robin Williams and Robert DeNiro, chronicled the neurologist's work treating patients who had spent decades in a catatonic state caused by encephalitic lethargica. Some of the patients emerged from their catatonia after Sacks administered the drug L-dopa.

In a 1985 interview, Sacks told Gross that watching the patients emerge from the catatonic state was like standing at "the intersection of fact and fable. You see infinitely moving, dramatic, romantic situations, but also clearly based on the state of the nervous system."

Fresh Air remembers Sacks with two interviews from 1985 and 2012.


Interview Highlights

On the catatonic state of the patients he described in Awakenings

I suppose the first impression was that I had entered a museum or waxwork gallery. They were motionless figures who were transfixed in strange postures — sometimes rather dramatic postures, sometimes not — with an absolute absence of motion, without any hint of motion. So everything looked frozen, and then, very suddenly, sometimes one of these patients would be released from this state and would speak and move, then you could see what a vivid, alive, real person was there, imprisoned in a sort of way by some strange physiological change.

On the sudden and gradual reactions to the L-dopa

The suddenness was incredible and nothing which I had read about gave me any hint of this. Patients with ordinary Parkinson's disease don't respond in this sudden way. They tend to warm up gradually, maybe one had seen, as it were, a built-in tendency to suddenness with these patients in the way in which they might suddenly snap out of things if there was a fire engine or a sneeze or something like this. Some of the patients came out more slowly, some instantly changed. With the patients who came out more slowly, one would see over a period of days a sort of melting of the rigidity of the frozen picture. There would be the beginnings of spontaneous movement, the beginnings of speech, the beginnings of attention and looking around, the beginnings of animation.

On the fable-like qualities of neurology

There was a quality of a fable about this in the spring in the summer of '69. I thought of the Sleeping Beauty, of Rip Van Winkle and all the others in a sort of way. ... There was great joy and a sort of lyrical delight in the world which had been given back. I remember one patient stroking leaves and looking at the nightlights of New York on the horizon and everything was a source of delight and gratitude. It was like seeing frozen figures thawing. And with this, a great delight as an awakening or sort of resurrection might be expected to have.

On a patient communicating with a spelling board before the L-dopa, "I have no exit. I'm trapped in myself. This stupid body is a prison with windows but no doors."

I think illness and deep illness may force one to think, even if one hasn't been a thinking person before. And perhaps force one to think in the terms in which all people think of, which are terms of metaphor, of the imagination, of myth. If you just catechize patients, if you give them the usual neurological catechism, if you interrogate them in a narrow way, you get narrow answers. Sometimes one has to do this sort of medicine, but I think this sort of quick interrogatory medicine is too common. At least in a chronic hospital you have in some sense, for better or worse, all the time in the world.

On trying hallucinogenic drugs

I think I sometimes just wanted pleasure. I wanted to see a visually and perhaps musically enhanced world. I wanted to know what it was like ... . I would often keep notes when I got stoned.

On a memorable hallucination while taking LSD

I had been reading about the color indigo, how it had been introduced into the spectrum by [Isaac] Newton rather late, and it seemed no two people quite agreed as to what indigo was, and I thought I would like to have an experience of indigo. And I built up a sort of pharmacological launchpad with amphetamines and LSD, and a little cannabis on top of that, and when I was really stoned I said, "I want to see indigo  now." And as if thrown by a paintbrush, a huge pear-shaped blob of the purest indigo appeared on the wall.

Again it had this luminous, numinous quality; I leaped toward it in a sort of ecstasy. I thought, "This is the color of heaven." ... I thought maybe this is not a color which actually exists on the Earth, or maybe it used to exist or no longer exists. All this went through my mind in 4 or 5 seconds, and then the blob disappeared, giving me a strong sense of loss and heartbrokenness, and I was haunted a little bit when I came down, wondering whether indigo did exist in the real world.

I would turn over little stones. I once went to a museum to look at azurite, a copper mineral which is maybe the nearest [to] indigo, but that was disappointing. I did in fact have that experience again, but when I had it the second time, it was not with a drug, it was with music — and I think music can take one to the heights in a way comparable with drugs.

On hallucinations that accompany bereavement

With any hallucinations, if you can do functional brain imagery while they're going on, you will find that the parts of the brain usually involved in seeing or hearing — in perception — have become superactive by themselves. And this is an autonomous activity; this does not happen with imagination. But hallucination, in a way, simulates perception, and the perceptual parts of the brain become active. ... There's obviously a very, very strong passionate feeling of love and loss with bereavement hallucinations, and I think intense emotion of any sort can produce a hallucination. ...

With hallucinations one remembers them, unlike dreams, and on the whole they're not like dreams because dreaming, you're asleep, you're only a dreaming consciousness, whereas here you're awake and observing yourself.

On the connection between drugs, hallucination and religion

I'm very intrigued by the relationship between drugs and religion and hallucination and religion. There's a long chapter [in Sacks' book, Hallucinations] on epilepsy, which, at one time was called the "sacred disease" — although Hippocrates said there was nothing sacred about it. ... There is a sort of seizure, which some people get called an "ecstatic seizure," when there will be a feeling of bliss or rapture, a feeling of being transported to heaven, sometimes of hearing angelic voices or seeing angels or communing with God.

Experiences like this can happen with seemingly quite irreligious people who have — who don't seem to have an iota of religious disposition, but the experience may be rather overwhelming and may lead to conversion.

Copyright 2015 Fresh Air. To see more, visit http://www.npr.org/programs/fresh-air/.

Transcript

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. Today we remember Oliver Sacks, the neurologist and best-selling author. He died yesterday at the age of 82. Sacks had been a physician and a professor of neurology at the New York University School of Medicine. His beautifully written books examine the mysteries of perception, memory and consciousness by drawing on his observations of patients with unusual neurological disorders and brain injuries that produced strange distortions. A case study of a man who mistook his wife for a hat became the title story of one of his best-known books.

Sacks also drew on observations of his own mind and body and some of the unusual conditions he lived with. He described himself as having face blindness, an inability to recognize people by their faces. Late in life he had visual distortions and hallucinations caused by a brain tumor behind his right eye. The tumor was removed, but he learned in February that the cancer had spread to his liver and he didn't have long to live. I had the honor of interviewing Dr. Sacks several times. We're going to hear excerpts of two of those interviews today. The first is about his 1973 book "Awakenings" which established him as a writer. It was adapted into a 1990 film starring Robin Williams and Robert DeNiro. "Awakenings" was about Dr. Sacks' work treating patients who had survived an epidemic of encephalitis lethargica which is commonly called sleeping sickness. The epidemic lasted from around 1917 to 1928 and left many survivors in a catatonic state. Those patients had been relegated to back wards and asylums. In 1985, Oliver Sacks told me how he came to treat patients who had survived this forgotten disaster.

(SOUNDBITE OF ARCHIVED BROADCAST)

OLIVER SACKS: When I was a medical student and when I was a resident of neurology in the '50s and the early '60s, it was scarcely ever mentioned. And so it was really a very great surprise to me in 1966 when I came to an out-of-the-way little hospital in New York and found 80 such patients.

GROSS: Could you describe what kind of state they lived in and what they looked like for the days you'd walk by?

SACKS: Well, I suppose the first impression was that I'd entered a museum or a waxwork gallery. There were motionless figures who were transfixed in strange postures - sometimes rather dramatic postures, sometimes not - with an absolute absence of motion, without any hint of motion, so everything looked frozen. And then very suddenly sometimes one of these patients would be released from this state and would speak and move, then you could see what a vivid, alive, real person was there imprisoned in a sort of way by some strange physiological change. Actually this hospital, which I called Mount Carmel, had been opened in 1919 precisely for such patients. And this is something which happened all over the world - that hospitals were opened or hospitals were turned over. For example, in London, the Highlands Hospital which was an immense fever hospital covering 70 acres was turned over and came to house 20,000 patients with encephalitis lethargica.

GROSS: A lot of the way we look is really a function of the lives that we've lead, you know, the posture that we have or how wrinkled our faces are, the expressions that our face naturally sets into. Now these are people who have had virtually no experiences for several decades. Did they look differently than average people do? Did their faces for their age look differently?

SACKS: Well, they did look more youthful than their age, partly in the sort of condition the face may itself be - rather frozen and not reflect feelings - but partly feelings and experience itself might be arrested as well as the physical arrest. And so as it were, the - some of the ravages and/or beauties which time inscribes - experience describes on the face were sometimes not there. I remember one of the nurses saying of one particular patient - the patient who I called Rose. She says that woman hasn't changed in the 30 years I've been here.

GROSS: Did they have any way of communicating at all?

SACKS: Well, for the most part they didn't. Usually simple communications about food and toileting could be made, but no complex communications could be made except in these rare moments or minutes of release or awakening which would sometimes happen spontaneously. Sometimes there would be something to provoke it (sneezes). A patient would sneeze and perhaps in sneezing he might suddenly jerk himself out of this trance. He might also jerk other people out of the trance. He would startle himself into wakefulness or perhaps a fire engine would come past. Sometimes some of these patients would respond to an emergency - if another patient had a fall or fell on the floor, someone who had been apparently unable to move a finger might leap out of his wheelchair, assist the other patient, and then fall back like a statue into his own chair.

GROSS: You - after several, I guess, years of research decided to administer the drug L-dopa and see what reaction it would have on them.

SACKS: Well, I saw these patients in 1966 originally. At that time, there was nothing which had any chance or any promise of helping them. And they themselves had probably entered a sort of hopeless state, perhaps - perhaps a stoical one, perhaps a despairing one. I think it varied in different patients. Early in 1967 - February of '67 - there came the news of a remarkable new medication, the so-called L-dopa, which - perhaps one shouldn't call it a medication as it was almost a nutrient because it would serve to replace a missing transmitter in the brain - the neurotransmitter dopamine which was severely depleted in Parkinson's disease. And patients with very severe motionless Parkinson's disease could be transformed by this.

I then found myself wondering whether these post-encephalitic patients who were Parkinsonian, but were much else. They were catatonic, they were entranced, they were - and knew not what. And they'd also been put away and out of the world for decades. So I was very excited, and I will say the patients who - some of the patients who in fact became aware of things - this ran through the hospital. There's a sort of seismic tremor early in '67 that there might be hope for such patients where there'd be no hope before. And these patients constituted a large group in the hospital - the hospital had been built for them. But first, one couldn't get hold of the staff, it was enormously expensive, it wasn't really available, one had to get a special license. And so two years passed before I actually gave it in March of '69.

GROSS: And you wrote that you were really surprised at the suddenness - at the immediateness of their reaction. What were the first signs that they were leaving that trance-like state that they had been stuck in?

SACKS: Well, the suddenness was incredible, and nothing which I had read about gave me any hint of this. Patients with ordinary Parkinson's disease don't respond in the sudden way. They tend to warm up gradually. Maybe one had seen, as it were, a built-in tendency to suddenness with these patients in the way in which they might suddenly snap out of things if there was a fire engine or a sneeze or something like this. Some of the patients came out more slowly, some instantly changed. With the patients who came out more slowly, one would see over a period of days a sort of melting of the rigidity of the frozen picture. There would be the beginnings of spontaneous movement. The beginnings of speech, the beginnings of attention and looking around, the beginnings of animation. It was like seeing frozen figures thawing and with this a great delight as an awakening or sort of resurrection might be expected to have.

GROSS: Did they have comprehension of what had happened and what was happening?

SACKS: Oh, absolutely. One had not quite known what they had before, but it became perfectly clear then, although the comprehension was of an odd sort. With one patient, the patient I call Rose in "Awakenings," she became very excited and rather salacious and was full of boundary jokes and songs. She was talking about Gershwin all the while. And she loved singing. And some of her gestures and some of her speech was of an obsolete sort. It sort of reminded me of a flapper - it reminded me of the 1920s. And I found myself thinking, where is this woman? You know, is she oriented? What's going on?

I asked her a few questions. She's a very quick woman. She says - look, she says, I know the date of Pearl Harbor. I know the date of Kennedy's assassination. She says I know it all. It's all recorded, she says, but none of it seems real. She says nothing has seemed real since that 1926 when I got the encephalitis and came to a stop. And she says I know I'm 64 and that this is 1969 and that I'm an elderly woman in a bizarre situation in a chronic hospital, but I feel I'm 21. I feel it's 1926. Now, for her there was a - then a tremendous anachronism between what she formally knew and when she actually felt.

GROSS: We're listening back to a 1985 interview with neurologist and author Oliver Sacks. He died yesterday at the age of 82. We'll hear more of the interview after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. We're listening to a 1985 interview with neurologist and author, Oliver Sacks, who died yesterday. In this interview, we talked about his work with patients who were left in a catatonic state from an epidemic of encephalitis. In 1969, he treated them with the drug L-Dopa, and several of these patients miraculously came out of their trance-like state. These patients were the subject of his book, "Awakenings."

(SOUNDBITE OF ARCHIVED BROADCAST)

GROSS: You know, it's sometimes interesting to fantasize about what it would be like if you were in a position like that - you know, if you were frozen for decades and then come alive and you think - God, I'd love - I'd appreciate life then so much more than I appreciate it now because everything would be so special - you know, every smell and taste and everything. Movement, itself, would be such a delight - everything we take for granted. But then would that feeling last very long? And what happened to these people was I guess because of the drug, then everything kind of backfired after not too long.

SACKS: Well, there was a quality of a fable about this in the spring and the summer of '69. I mean, I thought of "The Sleeping Beauty," of "Rip Van Winkle" and all the others. In a sort of way, it seems to me that I work or, perhaps, in neurology - certain sorts of neurology, one could work as it were at the intersection of fact and fable. You see infinitely moving, dramatic, romantic situations but always clearly based on the state of the nervous system and what's happening.

But yes, as you say, the first ever seemed to be the dawn of a new day, the birth of a new life. There was great joy and a sort of lyrical delight in the world which had been given back. I remember one patient stroking leaves and looking at the night lights of New York on the horizon. And everything was a source of delight and gratitude. This was the sort of quality at first. But then there were problems.

I - the problems one first saw were really problems of excess. The patients had had not enough life, not enough movement, not enough emotion, not enough dopamine before. And now, they started to have too much and things started to run away and joyous feeling became mania and normal movement became violent mobility, frenzy, tics, sudden movements, sudden excesses, sudden passions. It wasn't clear to me then how much this turning over to the opposite pole from trance to a sort of frenzy. They were coming to, and they were being awakened and animated but often in a vacuum - often to a world which no longer made sense for them, which had no place for them, in which they no longer had relatives, friends or anything.

This certainly seemed to be somewhat the situation with Rose. And she said, I hate your television world. She says, nothing has any sense to me. I don't care for it. With her in particular, after about 10 days of extraordinary but somehow anachronistic excitement, she relapsed or returned again - I don't know what word to use - or regressed to the strange - well, to the state she had been in before. And thereafter, nothing we could do made any difference. I couldn't help feeling there, in some sort of way, that her feelings or her will or her personality had somehow had the last word. But undoubtedly, physiologically, there is a tendency with these patients to go from one extreme to another.

GROSS: You wrote that many of them found some kind of middle state, eventually.

SACKS: The 1969 then, was a period of violent drama. They emerged from their trance, they awakened. Things were fine for a while. Then they got into various states of frenzy and sometimes frenzy alternating with trance and sometimes many times a day. But then, one way and another, for most of the patients - not all of them - some sort of happy medium and a sort of life became possible. Some of the patients did have friends and relatives outside and were able to leave the institution they had never thought to leave. With this institution, people usually only leave it in a box. Other patients who didn't have relatives, who didn't have support systems, to use the jargon, or who were still variously disabled stayed in Mount Caramel, but had a reasonably full life.

And the home - the hospital is full of resources of one sort and another, from gardens, to workshops, to music, to other things and quite a full social life - another life was possible. And in general, I'd say that whatever makes life possible for all of us, what Freud called work and love, was the most important thing - the most important non-chemical thing with them, in allowing some sort of stability.

GROSS: Well, I want to quote something that one of the people you administered the L-Dopa to had communicated through, like, a spelling board before the drug was administered. And he said, I have no exit. I'm trapped in myself. This stupid body is a prison with windows but no doors. Others found that kind of an immensely moving quote to read.

SACKS: I think illness and deep illness may force one to think, even if one hasn't been a thinking person before and perhaps force one to think in the terms which all people think of, which are terms of the - of meta-thought, the imagination, of myth. Now, if you just catechize patients - if you give them the usual sort of neurological catechism - if you interrogate them in a narrow way, you'll get narrow answers. Sometimes, one has to do this sort of medicine, but I think this sort of quick interrogatory medicine is too common. At least in a chronic hospital, you have, in some sense, for better or worse, all the time in the world. You have a sort of freedom, and a sort of depth of relationship can develop. And patients can express themselves, can grope for expression. But many of the patients seem to me to be poetic and, as it were, to have become poetic. Auden has a phrase about being wounded into art. And I sometimes felt this was the case with many of the patients.

GROSS: Oliver Sacks recorded in 1985. The patients he described were the subject of his book "Awakenings." Sacks died yesterday at the age of 82.

We'll continue our remembrance and listen back to a 2012 interview about hallucinations - his patients and his own - after we take a break. I'm Terry Gross, and this is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. I'm Terry Gross. We're remembering neurologist and author Oliver Sacks. He died yesterday, of cancer, at the age of 82. His beautifully written books like "The Man Who Mistook His Wife for A Hat" examine the mysteries of perception and consciousness by drawing on his observations of his patients.

This next interview was recorded in 2012, after the publication of his book, "Hallucinations," which describes patients who experienced hallucinations brought on by neurological disorders, brain injuries, medications, fevers, blindness and more - hallucinations that ranged from the terrifying to the transcendent. One chapter, called "Altered States," is about his own experiments with mind-altering drugs in the 60's when he was a neurology resident. He said these drugs connected with the reason he wanted to be a neurologist, which was to study how the brain embodies consciousness in the self to understand its amazing powers of perception and distortion.

(SOUNDBITE OF ARCHIVED BROADCAST)

GROSS: Dr. Oliver Sacks, welcome back to FRESH AIR.

SACKS: It's good to be with you again.

GROSS: So at the beginning of your chapter about your own experimentation with altered states, you write, (reading) every culture has found chemical means of transcendence. At some point, the use of such intoxicants becomes institutionalized at a magical or sacramental level.

What are you thinking of there?

SACKS: Well, I was thinking of peyote ceremonies with Native Americans, but similar ceremonies in Mexico with morning glory seeds, with ololiuqui, similar ceremonies in Central America with magic mushrooms, similar ones in South America with - I can't pronounce it - ayahuasca. And so there's - this seems to happen in every culture at some point.

GROSS: And you write that some drugs like hallucinogenic drugs promise transcendence on demand. Is that why you wanted to experiment with them?

SACKS: Well, I think it's one of the reasons. It's probably a little too high-sounding for all of my reasons. I mean, I think I sometimes just wanted pleasure. I wanted to see a visually and, perhaps, musically enhanced world. I wanted to know what it was like, and I think there was always an observer part, as well as the participant. I would often keep notes when I got stoned.

GROSS: What - did it seem absurd to you to keep notes on the experience because the experience was so heightened and can be so absorbing to take notes on it brings you outside of it while you're in it, which can seem absurd in that moment?

SACKS: Yes. Well, I didn't always take notes on it. I especially tended to take notes, I think, if a trip turned frightening. And then the taking notes would help me stand outside this, in a way.

GROSS: What was the first time you tried a drug that induced perceptual distortion?

SACKS: I think it was in 1963. I was in Los Angeles at UCLA -doing a residency in neurology, but I was also very much on the beach - on Venice Beach and Muscle Beach. And there, there was quite a drug culture, as there was also in Topanga Canyon, where I lived. And one day, someone offered me some pot. And I took two puffs from it, and I'd been looking at my hand for some reason, and the hand seemed to retreat from me but at the same time getting larger and larger until it became sort of a cosmic hand across the universe. And I found that astounding.

GROSS: So what did you find most interesting, pleasing or disturbing about that first experience that made you want to seek more experiences like it?

SACKS: I was fascinated that one could have such perceptual changes and also that they went for the certain feeling of significance, an almost numinous feeling. I'm strongly atheist by disposition, but nonetheless when this happened, I couldn't help thinking that must be what the hand of God is like, or how it is experienced.

GROSS: So, you started taking LSD in 1964, and you write that you took mind-altering drugs every weekend for a while. Give us a sense of one of the better experiences that you had that made you want to keep using it.

SACKS: Well, a particular experience was with a color. I'd been reading about the color indigo, how it had been introduced into the spectrum by Newton rather late, and it seemed no two people quite agreed as to what indigo was. And, I thought, I would like to have an experience of indigo. And I built up a sort of pharmacological launchpad with amphetamines and LSD and a little cannabis on top of that. And when I was really stoned, I said, I want to see indigo now. And as if thrown by a paintbrush, a huge pear-shaped blob of the purest indigo appeared on the wall. It, again, had this sort of luminous, numinous quality. I leant towards it in a sort of ecstasy. I thought, this is the color of heaven, or this is the color which Giotto tried to get all his life but never could. I thought maybe this is not a color which actually exists on the Earth, or maybe it used to exist and no longer exists.

And all this went through my mind in four or five seconds. And then the blob disappeared, giving me a strong sense of loss and heartbrokenness. And I was haunted a little bit when I came down, wondering whether indigo did exist in the real world. And I would turn over little stones - I once went to a museum to look azurite, a copper mineral which is maybe the nearest to indigo, but that was disappointing. I did, in fact, have that experience again, but when I had it the second time, it was not with a drug, it was with music. And I think music can take one to the heights in a way comparable with drugs. But I think the indigo was my favorite hallucination.

GROSS: So give us an example of a really bad time that you had on a hallucinogenic drug.

SACKS: Well, I think the worst time was also a rather puzzling time. It was in '65. I was new to New York. I was sleeping very badly. I was taking ever-increasing doses of a sleeping medication called chloral hydrate. And then, one day, I ran out of it. But I didn't think much of this, though, when I went to work, I noticed I was rather tremulous. And at that time, I was doing neuropathology, and it was my turn to slice a brain and describe all the structures, which I usually enjoyed doing and did easily. But this time it was difficult, and I hesitated, and I felt my tremor was becoming more obvious.

When the session was over, I went to have a coffee across the road, and suddenly, my coffee turned green and then purple. And I looked up, there was a man paying at the register and he seemed to have some - a huge proboscidean head, like a sea elephants. I was panicked. I didn't know what was happening. I ran across the street to a bus, got on it, but the people on the bus terrified me. They all seemed to have huge, egg-shaped heads with eyes like the eyes of insects. I somehow managed to get off the bus and onto a train and get off at the right stop. When I got back to my apartment, I phoned up a friend of mine - we'd interned together. And I said, Carol, I want to say goodbye. I've gone mad. And she said, Oliver what have you just taken? And I said, I haven't just taken anything. And she thought for a moment and said, what have you just stopped taking? And I said, that's it - the chlor. And so this was the beginning of an attack of the DTs - the delirium tremens. Not induced by alcohol withdrawal, but by chloral withdrawal. It's a dangerous state. I should really have checked myself into hospital, but I didn't. I thought I wanted to go through it with some kindly medical supervision, and I did. But there were many, many terrifying things there.

GROSS: Was it helpful - while you were having these nightmarish hallucinations, because of withdrawal from the medicine that you were taking - to know that they were medically-induced hallucinations, that you weren't losing your mind and that this was going to end?

SACKS: Yeah, absolutely. When I realized it was medication and not madness, that was a relief so huge that I felt I could sit through the rest of it.

GROSS: As a neurologist, what did you learn from that experience?

SACKS: Well, I think I learned that one shouldn't be silly. But in particular, from that experience, there were all sorts of particular odd visual perceptions. Sometimes I could not see continuous motion. I would only see a series of stills, and that fascinated me very much. And it made me, in fact, wonder whether the sense of visual motion is an illusion, whether, in fact, we see a series of stills. I don't think I'd had that thought until I was seeing stills. And with hallucinations, one remembers them, unlike dreams. And on the whole, they're not like dreams, because in dreaming you're asleep - you're only a dreaming consciousness, whereas here you're awake and observing yourself.

GROSS: We're listening back to an interview with neurologist Oliver Sacks recorded in 2012. He died yesterday at the age of 82. We'll hear more after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. We're remembering neurologist and author Oliver Sacks. Let's get back to our 2012 interview recorded after the publication of his book "Hallucinations."

(SOUNDBITE OF ARCHIVED BROADCAST)

GROSS: So you know how some people say the human brain is wired for God - you know, wired to have religion? What's your take on that?

SACKS: I'm very intrigued by the relationship between drugs and religion and hallucination and religion. There's a long chapter on epilepsy, which at one time was called the sacred disease, although Hippocrates said there was nothing sacred about it. Although he allowed that sometimes the symptoms of epilepsy may be visionary. And in particular, there is a sort of seizure which some people get called an ecstatic seizure when there will be a feeling of bliss or rapture, a feeling of feeling transported to heaven, sometimes of hearing angelic voices or seeing angels or communing with God. Experiences like this can happen with seemingly quite irreligious people who have - who don't seem to have an iota of religious disposition. But the experience may be rather overwhelming and may lead to conversion.

GROSS: But it's interesting how often those visions - if we want to call it that - come from something that nowadays would be diagnosed as a disorder and in fact are disorders like epilepsy or schizophrenia.

SACKS: Yes. Well, certainly I think there probably always been visions and voices and these were variously ascribed to the divine or the demonic or the muses. The medicalization of hallucinations really only occurred in the 19th century. And following that, people became, I think, very much more anxious about hallucinations - secretive and ashamed. And the subject was much less discussed. I think hallucinations need to be discussed. There are all sorts of hallucinations and then many sorts which are OK, like the ones, I think, which most of us have when we're in bed at night before we fall asleep, we can see all sorts of patterns or faces or scenes.

GROSS: If you're just joining us, my guest is neurologist Dr. Oliver Sacks. His new book is called "Hallucinations," and it's about medically induced hallucinations, naturally occurring hallucinations like between waking and sleeping and hallucinations that are side effects of drugs, hallucinations that are called by various medical conditions.

SACKS: And can I add to your list of hallucinations - which are caused by real-life experiences, such as bereavement.

GROSS: Yes, I'm glad you mentioned bereavement. And that is such a common form of hallucination where, you know, you've lost somebody who you love and you think you've seen them or heard them say something. And when that happens, I think it's fair to say it feels like a visitation. How would you describe that?

SACKS: Well, someone dies, there's a hole in your life and that hole can be briefly filled, I think, by a hallucination. Typically, the bereavement hallucinations which are common - something like 40 or 50 percent of bereaved people get them occasionally - often felt as very comforting and they may help one through the mourning process. And then when one has mourned fully, they disappear.

GROSS: How, as a neurologist, would you interpret those hallucinations?

SACKS: Well, with any hallucinations, if you can, say, do functional brain imagery while they're going on, you will find that the parts of the brain usually involved in seeing or hearing - in perception - are in fact being - have become super-active by themselves. And this is an autonomous activity. This does not happen with imagination. But hallucination, in a way, simulates perception. And the perceptual parts of the brain become active. And - but you know, what else is going on? There's obviously a very, very strong passionate feeling of love and loss with bereavement hallucinations. And I think intense emotion of any sort can produce a hallucination.

GROSS: I'm just curious - like, how do you do functional brain imagery of somebody who has had a hallucination? I mean, they're probably not hooked up to the fMRI when they're feeling like they had this visitation from a lost loved one.

SACKS: Well, there, it would be difficult because hallucinations like this are rare and sporadic and unpredictable. But there are other people - and I'm especially interested in this because I've worked in old-age homes for the last 40 years or so - and I've seen many, many elderly people who are intellectually intact but have impaired vision or hearing, have visual or auditory hallucinations on this basis. The visual one they called Charles Bonnet Syndrome, and people may see faces; they may see landscapes, patterns, musical notation for hours a day. And in this situation, you can have someone inside a functional MRI, and they can say, raise a finger when they are hallucinating. You may then say to them, you were hallucinating faces. They may say, how the hell do you know? And you will say, because the face-recognizing part of your brain suddenly became very active.

GROSS: Wow.

SACKS: And it's really - and is this sort of thing, especially with patients with Charles Bonnet Syndrome that you can plot, you can map the brain by the sort of hallucinations people get.

GROSS: We're listening back to an interview with neurologist Oliver Sacks recorded in 2012. He died yesterday at the age of 82. We'll hear more after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. We're remembering neurologist and author Oliver Sacks. Let's get back to our 2012 interview, recorded after the publication of his book, "Hallucinations."

(SOUNDBITE OF ARCHIVED BROADCAST)

GROSS: You write in your book "Hallucinations" about an auditory hallucination you had that really might have saved your life. You were mountain climbing, and you had injured your foot or your leg. And part of you just wanted to just, like, slow down, sleep, but then you heard a voice which said what?

SACKS: The impulse to sleep - I'd torn off most of the thigh muscles. The knee was dislocating backwards. At one point, I got quite shocked and thought it'd be nice to have a little sleep. And the voice said, no, that would be death. Go on. You've got to keep going, find a pace you can keep up and keep it up. And this was a very clear, commanding voice. It was a sort of life voice and was not to be disobeyed.

GROSS: And so you kept going in spite of the horrible shape that your leg and knee was in.

SACKS: Yeah, I was sort of weighing myself down with my arms. I'd splinted the leg as best I could with an umbrella stick and my anorak, which I had torn too. Incidentally, I thought that was going to the last day of my life and it had every prospect of being. But I was found, at twilight, by two hunters. This was in north Norway.

But that voice was crucial for me. And I've heard many other stories like this. One of them was from a young woman who was brokenhearted after a love affair and determined to commit suicide and she had a bottle of sleeping tablets and a tumbler of whiskey to wash them down. And she had raised the tablets to her mouth when she heard a voice saying, don't do that. I wouldn't do that if I were you. You won't always be feeling the way you're feeling now. This was a man's voice. She didn't recognize it. She was fairly startled. She said, who was that? Who was that? She said a figure materialized in a chair opposite her for a few seconds - a figure in 18th-century dress that vanished. But she feels that hallucination saved her life. And I think her story is not that uncommon, nor mine for that matter.

GROSS: Whose voice did you hear? Was it your voice, a stranger's voice?

SACKS: Not to my voice. I often hear my voice. I'm always sort of cursing or muttering to myself. But this was a very clear, a short voice, not a voice I recognized, but a voice I trusted and which I suppose I realized came from some part of me because there's no other place that it could've come from.

GROSS: It seems to me you've had a very neurologically eventful life.

(LAUGHTER)

GROSS: Honestly, like you've had migraines from, like, the age of 4, and you heard the voice when you were mountain climbing and would have died had you not kept walking in spite of a severe leg injury. You've had spinal pain and, you know, wanted to understand the, you know, nerve causes of that. You've had visual disorders. And it just seems like you - you have experienced so much which I know has been useful to you as a doctor. But it seems like a lot for one person to go through.

SACKS: (Laughter).

GROSS: You've lost your sight in one eye because of cancer. And that started out with all kinds of distortions.

SACKS: Yes. Well, it has been a lot in a way. But I'm - I feel I'm lucky. I'm close to 80, and I'm still in fairly good shape, especially if I can go swimming. I limp a bit on land, but I'm powerful in the water. And it's true, I've only got one eye now, and the other one needs of some surgery. But I manage. I suspect that most people may have quite a lot of neurological things to which they don't pay much attention. I think I probably differ from others only in having paid attention to things.

GROSS: Well, Dr. Sacks, it's just such a pleasure to talk with you. You're always so interesting. I thank you so much for coming back to our show.

SACKS: Well, thank you so much, and I always love talking with you. And I love the way you keep me focused or you try to keep me focused, although I'm incorrigible.

(LAUGHTER)

GROSS: You're great.

Oliver Sacks recorded in 2012 after the publication of his book, "Hallucinations." He died yesterday at the age of 82 of cancer. As one of his many readers and as someone who had the privilege of interviewing him several times, I'm grateful for how he helped me better understand the mysteries of perception.

(SOUNDBITE OF MUSIC)

GROSS: In order to remember Dr. Sacks today, we postponed our interview with Jonathan Franzen. We'll hear from him tomorrow. Franzen is the author of the best-sellers "The Corrections" and "Freedom" and has a new novel called "Purity." It's in part about keeping secrets and exposing secrets.

JONATHAN FRANZEN: I'm in the business of the betraying secrets about myself. I'm not going to tell you everything, but I'm going to tell you more than most people would tell the world.

GROSS: I hope you'll join us tomorrow. Transcript provided by NPR, Copyright NPR.

300x250 Ad

Support quality journalism, like the story above, with your gift right now.

Donate