In Our Time - Neuroscience in the 20th century

Episode Date: December 24, 1998

Melvyn Bragg and guests marvel at our brains and discuss how at the end of a century of research we still understand so little about how they work.Developments in the understanding of the brain represent one of the major leaps forward in science in the 20th century, and the research is gathering pace and intensity. It’s a subject which captures the imagination, particularly the search for consciousness whatever that might be, and brings together some of the newest technology and the oldest belief systems. What a piece of work is the brain - a grain-of-sand-sized piece contains one hundred thousand neurons, two-million axons and one billion synapses which all talk to each other. How far we have got with our understanding of the brain and what can it tell us about ourselves and the world we live in?With Professor Susan Greenfield, director of the Royal Institution, Professor of Pharmacology, Oxford University and Professor of Physics at Gresham College; Professor Vilayanur Ramachandran, Professor of Neuroscience and Psychology, Director of the Brain Perception Laboratory, University of California in San Diego and Professor at the Salk Institute.

Thanks for downloading the In Our Time podcast. For more details about In Our Time and for our terms of use, please go to BBC.co.com.uk forward slash radio four. I hope you enjoy the program. Hello, we'll be talking about the brain and the latest work on that most fascinating of subjects, which is also an incredible object. I'm joined by Professor Susan Greenfield,

who's the current director of the Royal Institution, the first woman to have held the post. She's also Professor of Pharmacology at Oxford University and Professor of Physics at Gresham College. She's written several books, including the human brain, A Guided Tour. And Professor Ramachandran, Professor of Neuroscience and Psychology, and Director of the Brain Perception Laboratory at the University of California in San Diego, and a professor at the Salk Institute.

His new book is called Phantoms in the Brain, Human Nature, and the Architecture of the Mind. The Nobel Prize winner, Francis Crick, said of this book, if you're at all interested in how your brain works, then this is the book you must read. I begin by quoting from the preface of that book, The famous saying, may you live in interesting times, has a special meaning now for those of us who study the brain and human behaviour. On the one hand, despite 200 years of research, the most basic questions about the human mind, how do we recognise faces, why do we cry, why do we laugh, why do we dream,

and why do we enjoy music and art, remain unanswered, as does the really big question, what is consciousness. On the other hand, the advent of novel experimental approaches and imaging techniques is sure to transform our understanding of the human brain. brain. Looking at one way, Susan, after 200 years and all your work, and why don't we know a few of these things? I think one of the problems is that we're getting a bit carried away with the techniques and not really asking what we're going to use the techniques for. And I think I can give you three examples. One is imaging, where we can have windows onto the living

human brain now by exploiting the fact that it's very greedy. And that will show you different parts of the brain lighting up while someone's doing something. But if you think about it, all that will show you is what areas. is of the brain light up when someone's doing something that doesn't tell you how they're working together or why they're lighting up like that, it just shows you that they are. I think another technique that people are a little bit over-infatuated with is that of molecular biology where people now think they can isolate the gene for motherhood or the gene for gayness or the gene for criminality. And again, whilst it's true that genes are very important

for determining the availability of certain chemicals in your brain, those chemicals are like bricks or parts of bricks are to houses. They're not the whole story and it's how they're organised and how they all work together that's very important and again I think that's often ignored. Finally I think another technique that seduce people is that of neuronal nets. That's to say artificial silicon systems where people think they can build a conscious robot or that they can by building an artificial device understand how the brain works. And again I think the problem there is that they're putting a premium on learning a memory and not on the real feel, the real emotion of being a person So I think all these techniques, while they're helping us understand little bits,

they're not actually addressing the central issue, as I remember a sort of consciousness and of subjectivity, and that marvellous sensation that you have a private inner world in there. Nevertheless, there's a lot there, ordinary things about how we behave, why we'd laugh, why we'd cry, that he's saying we don't know about it after two centuries of increasingly intensive research, and we know this is the decade of the brain or whatever it is and so on. So how near are we to knowing things like that?

I think we're nearer to knowing how things correlate, how different phenomena and processes in the brain match up with states of mind. For example, you could give someone Prozac or morphine or LSD and you could see certain configurations and chemicals change in the brain, and you could match that up with a change in how happy someone felt. That doesn't tell you, however, why it is that an increase in this chemical, let's say, serotonin, stops you being depressed. or if you give someone Parkinson's disease a chemical that allows their brain to make more dopamine, why that dopamine is needed for movement. It doesn't tell you those things. So I think we are very near to looking at correlations, that's to say how things match up, but we are still completely bereft, completely ignorant about how to establish causality,

how one thing causes the other. Professor Ramashandran, having laid your quotation on you, which is never polite thing to you at this time in the morning. How do you regard research into the brain at the moment? Do you think... I agree with Susan, for example, about the imaging techniques. It's an interesting observation that for the longest time, psychologists and behavioral scientists took great pride

in being functionalists. In other words, we're not really interested in exactly where in the brain these things are occurring. We want an understanding of how it takes place. And yet, when the imaging techniques have arrived, they take this tremendous voyeuristic delight in looking at exactly what's happening where. So there's a sort of backlash from the early days of functionalism. But as Susan was saying, that's not enough.

We want to know exactly how it works, not merely where each function is taking place, but it's a good beginning. The second point I want to make is if you compare the history of ideas, say, in biology, which is about the same history as the same duration as psychology, you find many of the basic questions have been answered. Why do offsprings of goats look like goats and not like pigs, the problem of heredity? How do cells divide?

How do we reproduce the DNA, you know, the structure of DNA molecule and so on and so forth? All the basic questions have been answered, or many of them have been answered. But in psychology, if you ask equivalent questions, such as, why do people laugh? Why do they cry? Why do we dance? Why do everybody, you know, when there's rhythmic sound, feel like moving your body? body up and down. It's a very basic question. Nobody has any idea why we do it. And all these basic questions have not been answered. But that's not a pessimistic view because I think the picture

is changing very rapidly. But your way to go at this answer, you've described your method as tinkering about, which is very charming. And then you proceed to tinker to great effect in your book. Nevertheless, you chose the word deliberately to give, I suspect you tell me, if I'm wrong, an impression of wandering around rather speculatively, not aimlessly, but with your imagination open and your scalpel firmly in your back pocket. Why did you use that word tinkering so emphatically? Well, simply because I think that every science goes through these obvious stages. There's an early stage where you're just roaming the landscape and looking for an interesting phenomenon to investigate. Much as Faraday was doing with bits of wire and magnets and moving

them, there's no overarching theory guiding his research. It was just driven by curiosity. But of course, you learned a great deal by this tinkering. And then that set the stage for the Maxwell's equations and all of that. And what I'm arguing in the book is neuroscience is really in the Faraday stage, the tinkering stage, delaying the basic groundwork discovering phenomena stage, not the stage of lofty theoretical speculation. Susan. I think one of the exciting, I don't sound too pessimistic here

because I think we're at a very exciting time for brain research. I think one of the problems has been up until now that the psychics, psychologists have been operating in what they used to call the conceptual nervous system, irritatingly abbreviated to CNS, which, of course, stands for central nervous system as well. And they used to work with these boxes and arrows instead of real brain circuits. And up until very recently, they were completely divorced from the so-called bottom-up neuroscientists, the sort of work that I do, where you work on a cell-to-cell basis, where you look at the chemicals that squirted out from one brain cell to another.

And I think we might start now to see an increasing dialogue between the so-called, called cellular people, the bottom-up people, with the people that before used to just draw boxes and arrows. And if we can do that, I think we are going to make a very important stride because it means that we can actually root these very sophisticated concepts like laughter actually in the real physiology of the brain, rather than with boxes and arrows saying comparator and filter and so on, which is how they used to be expressed. Except the complication of the brain seems to be so incredible. The staggering facts and figures poor out of your book, more combinations

and there are elementary particles in the universe and so and so forth, that it does seem, I mean, the needle in the haystack seems to be a fairly straightforward assignment compared with what you're doing, but can I just come back to this tinkering? In one specific area, your book is called Phantoms in the Brain, and you've done an enormous amount of work of work on the phenomenon of phantom limbs.

Can you explain why you think that is interesting with regard to studying the brain? Well, very briefly, I mean, Here's a striking clinical observation, nonsense antiquity really, but at least for 100 years, these patients have been studied systematically. An arm is amputated and the patient vividly feels the presence of the missing arm. We call this a phantom arm. And question is, why does this happen?

And he feels the fingers and it can feel pain in the arm that doesn't exist and so on. And so on. Of course, he's aware of the fact that he doesn't have an arm, but it's a very vivid sensory illusion, the presence of the arm. And why does this happen? One of the things we found was if you simply touch this, person's face, the patient's face, with a cuttle bud, he will experience sensations as emerging from his missing fingers, from his phantom fingers. What is this telling you about

the brain? I think quite a lot. It turns out there's a complete map of the surface of the body on the opposite side of the brain. So the left side of the body, for example, is mapped on the right side of the brain. It's a systematic point-to-point map. And it turns out on this map, the hand representation is right next to the face, representation on the map. So when the arm is amputated, the hand is gone, the patch of cortex of brain that ordinarily receives signals from the hand is not getting any messages. What then seems to happen is that the input from the face, the sensory input, invades the territory corresponding to the hand. So when you touch the face, the message is going to the wrong part of the

brain, is going to the hand area, fooling the person into thinking that the fingers are being touched. So it's a very simple clinical demonstration with a cotton bud, but it's telling you there's been this massive reorganization of maps in the brain, often in an astonishingly short period. So what does that massive reorganization of maps with the brain tell you about the brain? Well, one of the things it's telling you is the picture of the brain you get from textbooks, that all these fixed connections in the adult brain must clearly be wrong. It's a much more dynamic pattern.

And in fact, one of the things every medical student has taught is that neural connections are laid down in the fetus, and that you can't change these connections in the adult brain. But in fact, that's not true. What you're seeing here is massive reorganisation. One of the things that comes, of course, with a phantom limb, is terrific pain. Now, pain interests you, Susan.

You've written about this as being something that you can learn from and you can teach you about the brain. Again, it's a very simple question. Why is pain useful as an instrument of investigation here? Well, as Remus says himself in his book, pain is in your head. Pain is not out there in the real world. We know that if people have pain at different times

through the day, they'll perceive, for example, at lunchtime, the pain less than other times. If you're anticipating pain, then it's perceived as more. So we know there's a very subjective element to pain. I've also heard reports that patients on morphine will sometimes say they still feel the pain, but it doesn't matter anymore. There's no significance anymore. Now, this is, for my mind, absolutely fascinating, because I think this is a very interesting way in to understanding consciousness.

I think that we should look at the ways in which a drug, for example, can make something not matter. And if we knew how that worked with the connections between brain cells, then we might actually have a handle on looking at the subjective, the issue that often scientists tend to forget, which fascinates philosophers,

and I think is the baby out with the bath order if you ignore it, and that's the whole point about consciousness is that it's subjective. But that is a key point in this particular area of science, isn't it, Ram? Because the subjective has been the enemy of science for a very long time, and yet the subjective is part of this investigation. Absolutely, and study.

these patients who have damaged parts of the brain and allows you to actually get to these very deep subjective questions, what I would like to do is link two of the ideas that we just mentioned, pain and laughter and humor, which seemed completely unrelated. But I saw a patient in India not long ago who has a condition called Asim Bullia for pain, which simply means if you poke her with a needle,

a normal person would say, ouch, and withdraw the hand. What she did instead was every time I poke her with the needle, she started giggling incessantly and couldn't stop laughing. So I asked her why are you laughing? And she said, well, it's very odd, doctor, because I feel the pain, but I don't experience the agony. So this is just pain is actually multi-layered, as Susan was just saying. And in fact, in this patient, what happened was this damage to an area called the insular cortex,

which receives pain signals and transmits the signals to the emotional centers in the brain, including the singular, where you experience the agony. So you first experience the sensation, and then you experience the agony. and it's two different places in the brain. Now, if these are disconnected by the damage, you get this paradox where the patient experiences the pain, but not the agony, and starts laughing because it's the only way she can kind of make sense.

Does this take us to Freud? Sorry, you would say something. Yes, I've also been fascinated by the connection, the seeming paradoxal connection between laughter and joy and actual pain. Although I think I've come to it from a different way than Ramah does, and that's with the onset of anisea. When you give someone anesthetic, first of all, you go through a so-called analgesic phase

where you don't feel pain. And then in olden times, before anaesthetics became as efficient as they did as they are today, in the old days people actually used to go to parties called ether frolics, or they had affairs take nitrous oxide for the euphoria it produced. Now, I'm fascinated, therefore, that on the way to becoming unconscious, to losing your conscious, you go from not feeling pain for things not to mattering, to feeling euphoria, and then, of course, into this dreamlike state that people seem to crave when they take morphine. And I'm just wondering, therefore, whether there is a relationship between certain brain states

where you feel happy or more alert and then where you don't feel pain. For example, we know that schizophrenic people have a higher threshold for pain. That's to say they feel pain less than non-sizophrenic people. My own view is that this is connected with a chemical in their brain called dopamine, which will change the configurations of their brain. So I think it's fascinating to explore from the two angles we've just said. I don't know who's right or wrong if they go together. But certainly paradoxically, these two things could come.

come together. What is interesting at this moment about brain research, it seems to me that it switches from one level of entry into another. You're talking chemically at one stage. You're talking psychologically another stage. You're not having to imaging at another stage. Can I just come to Freud, if I may, because this almost spans the century, doesn't it, at the beginning of the century, let us say. There he had this great map. And then he became towards the end of century massively discredited. And yet both of you, who, without being silly about it, are leading neuroscientists, have gone, if I may say, back to Freud.

and you have preservation around him, but you say undoubtedly he was a genius and this is what he did. And why is he important to you now as a neuroscientist? Now I'll turn to Susan, of course. Well, a couple of things. First of all, I think that Freud's, the general idea that your behavior is actually governed by a very large number of processes of which you're largely unconscious. It turns out it's right on the mark. And these are the very processes we're studying when we're studying these patients. So he's 90% unconsciousness is he's right on the mark.

I wouldn't give it a percentage, but something like that. But he also was addressing the key questions like laughter or sexuality, which interests everybody. The trouble is he was so much ahead of his time, and at that time they simply didn't have the techniques or even the conceptual tools to answer these questions. So the theoretical scaffolding he created was very nebulous. But the questions he raised are still perfectly valid and important. I remember talking to Oliver Sacks when he said that what Freud had done was the equivalent of Darwin's Hall being. brought back from the Galapagos, it was the precise of government. Would you go along with that?

Oh, absolutely. I think he has tremendous insight into human nature and asked the right questions, but he didn't have the sophisticated... But in terms of pain that we were discussing, what about his theory of denial? Well, I'm very interested in this mainly because, again,

because of the patients I see, there's one group of patients who have stroke damage occurring to the right hemisphere and they're completely paralyzed on the left side of the body. Now, majority of these patients complain that they're paralyzed as they should. But there's a tiny fraction about 5% of these patients who will look at their paralyzed arm and flatly deny that it's paralyzed. They'll say this arm is fine, doctor, even though they're mentally quite lucid and alert,

and they can see perfectly clearly that the arm is not moving. So what I've tried to argue in the books is that by looking at these floridly exaggerated examples of denial that you see in these patients, this might give you an experiment. handle on understanding some of the more common types of denial that we all engage in. This is an aspect of Freud, isn't it, Susan? He takes exceptional cases, and Rama takes exceptional cases in his book. Now, you like to, scientists like to deal in big numbers and big averages and big statistics, isn't they?

But we also deal in caricatures. Yes. In that you always, in an experiment, have to take a caricature situation, something that is abnormally large or abnormally small. So whenever you do an experiment, you wouldn't try and simulate it. what's called a physiological situation, because you want to have a very clear and unambiguous results. So you start off with something that is florid, that is an extreme, but it's not to say that it's qualitatively different, it's quantitatively different. That's to say it's not

some bizarre extra thing that some poor person has bolted onto their head that no one else has. Quite often one can look at such cases and see them as extreme or florid examples of real life. Do you see Freud as helping you in your work to some way towards a unified theory, which is lacking of the brain. It's completely lacking, isn't it? So do you see him being pointing as a signpost in that direction? Yes, one of the reasons I'm a huge fan of Freud, contrary to many people nowadays, is that I applaud anyone, anyone, who has a theory of how the brain might work, even if it's wrong.

If they are generating, as Popper would say, falsifiable hypotheses, I applaud them because at the moment I think a big problem with many contemporary neuroscientists is that they can't see the wood for the trees, they're eye dotting and T-crossing and focusing on one small phenomenon of process, one tiny fact about the brain rather than seeing how those facts relate to each other or putting it into a great framework. I think what brain research lacks at the moment

is we haven't got enough theory. We have too many facts and not enough theory. And I think that Freud did a great service providing a theory. Now, of course, with the hindsight of being 100 years on in our high-tech world, of course we can jeer and jive and mock and so on at some of the things. But on the whole, I think what he was trying to do,

what he was trying to approach, the fact he was talking about emotions, which scares a lot of neuroscientists off and subjectivity and laughter is something that really he should get enormous credit for. And myself, what he's helped me is this paradox of emotion versus reason

and myself am now evolving a theory of emotion that is not the same as his, but is certainly grounded in this idea of how do these two things seem to relate together, this logic, this rationale, versus the spontaneous, the road rage, the cream rationale. Well, I was going to say one of Freud's failings,

I'm also a fan of Freud, by the way, but one of his failings was he never any systematic experiments on all these phenomena that he was talking about. The advantage with studying the patients of the kind that I investigate, for example, a patient named Esmeralda was just telling you about who denied that her left arm was paralyzed, you can ask a very simple question. How deep is the denial? In other words, this is just a facade? Is she putting on a show, pretending, if you like, or malingering? Or is she really and truly convinced that she's not paralyzed? And you can actually do experiments to probe the depth of the denial.

experiments of the kind that Freud only dreamed of but never actually conducted. And this is the tremendous advantage of studying these patients because you can actually do experiments on them. Isn't there a huge divide between the Freudian going into emotions, discussing that, and something you say, the materialist view, which you say in your book again, it seems somehow, I'm quoting, disconcerting, Matild that your life, all your hopes,

triumphs, and aspirations simply arise from the activity of neurons in your brain, but far from being humiliating. this idea is ennobling, I think you go on and so on. But isn't there some difficulty that people have in equating laughter, tears, love, passion, with a lot of neurons buzzing around, looking for other neurons to mate up with? Well, they're not incompatible descriptions. I mean, they're actually, if you explain something in terms of its component parts interacting, you're not explaining it away.

In fact, you're providing a solid foundation. In other words, if I said, I'm in love with somebody, I'm giving her a rose, and you say, well, here's this cascade of chemicals that's producing this, it doesn't mean, well, love doesn't exist anymore. It's just a different level of description. In fact, it enriches your conception of love and your understanding of love. And you say, well, it's not some abstract idea anymore. In fact, there's a solid foundation.

So far from dispelling the idea of love, it should, in fact, enrich your idea of love and make it even more real in some sense. I think also it helps us, because the more we can understand about these things, the more we can combat the scourges of society, like why people get depressed, why people take drugs, why they go bungee jumping, which is incidentally always fascinated me.

I think the more insight we can get into the human mind, the more we're going to be able to help people. So it's not so much that in our vanity, we wish that we were kind of beamed in from Planet Zog or something. It's much more that if we can have insight, then we can, as Rama says, appreciate things more. If you know why you like claret

or why the taste is nice to you is because of the composition of the particular wine, then that helps you understand and select in the future so you can enhance your joy in taking Clarit. It's a bit like that with the... But how near is brain research in explaining things that matter still to millions and millions of people on the planet and has mattered for centuries and civilisation? Let's take one thing, the religious impulse,

the belief in belief. Is brain research at the moment getting anywhere near that, explaining that? No, but what I find interesting is the link there because I think... we are very much creatures that want to be more than the material. And just as you might find it spooky, that we can boil down to material things like brain cells. So most of us like to think that we can appreciate the world in a non-material way,

that we crave and need and enjoy and celebrate things other than the physical objects around us. And I think that's a very interesting insight into the human condition. As far as I know, certainly not in Britain, I can't see the medical research council giving anyone any money at the moment. and this parlous state of affairs we are for the neuroscience of religion. But I do find it very interesting that we do have, rather like children dream, rather like when we are dreaming, a way within our brain of imbuing the outside world

or certain things that happen in the outside world with the significance that is not validated by their particular properties. We can give things an added significance or an added symbolism than they might deserve just in sacophysical terms. You take your materialism and the fact that it is neuro-referical, are responsible for everything and we'll be seen. You take it, you actually take it back, if I may, so you take it across to Eastern mysticism, don't you? Yes, to the extent that, you know, the distinction between the self and the idea that you are a soul that aloof from the rest of the universe and engaging in this lofty inspection of events around you has always been considered to be an illusion in Eastern mysticism, especially in Hindu philosophy.

And it's a great irony to me that, you know, you do all this research in the brain. and essentially you're learning the same thing, except, of course, you're learning exactly how the illusion comes about, and the illusion of self and the illusion of, you know, you're inspecting the world and so on and so forth. But there is a certain similarity here, which I find tantalizing. Consciousness is a subject which has been discussed again and again. You talk about it not as philosophical, logical, or conceptual issue,

but rather as an empirical problem. What do you mean by that? Well, what I mean is it could very well be that the word consciousness, is a bit like the word happiness or the word love or even the word life. In other words, there's actually many different things, and you're lumping it all together into one word for conversation. And once you dissect the different components, it might be possible to map each of those components to specific neural structures

and enrich your understanding of what consciousness is. So, for example, we know that when you say happiness, it involves joy, it involves comfort, it might involve, there are several obvious components that go into it. Likewise, consciousness involves self-consciousness, being aware of yourself, just the awareness of something, awareness of pain, and there are umpt in a body image, the fact that you're embodied, the fact that you're passionate, you have emotions.

And each of these you might be able to explain, but there's no final climactic solution in much the same way that, you know, DNA was a solution for the problem of heredity. There may be no equivalent solution for the problem of consciousness. Stuart Sutherland said that it's impossible to specify what it is, what it does, why it's evolved. He said nothing worth reading has been written on it, which seems to be hard to see you. What do you feel about consciousness? And where we are with dealing with it now today.

I certainly feel if you have an attitude like that, imagine if Christopher Columbus had someone like that on board. They'd have never got past Lisbon Harbourer with it. And I find that rather sad, especially from a scientist, to have such a negative attitude. I go along with Rama that consciousness means many things to many people. and the fact that we can't define it, I think, is because it's bigger than everything else. Normally we define something by referring to a higher set, so you define love as an emotion, a table as a piece of furniture, father Christmas as a mythical creature,

conscious as a, and then that's where some people say a property of the brain, but that makes it very banal. And I think because it encompasses everything else, including the universe, we can't refer it to a higher set. So rather than fret, because I'm a philosopher, I'm not a philosopher, rather than fret about those things, I'd rather get on and try and see how it's generated by the real brain. I agree. I think it's not so much a problem. It's the ultimate challenge. It's not a simple, single problem that could be solved by one experiment. But I think it's a very exciting challenge.

Susan thinks of consciousness as a continuum from what I read of your work. You don't agree with that, do you? Well, what I would argue is that just as we know, obviously there was a time when people said, you know, were panpsychists. People used to think everything is conscious. We now know it's the brain that's conscious. The liver is not conscious. the heart probably is not conscious, but it's in the brain. You can narrow this scope of this further and say it's not the entire brain, but certain parts are critically involved. And it may be that certain functions and certain circuitry is more relevant to conscious experience than other functions.

And we know, for example, that are patients who engage in very elaborate actions without having any conscious awareness of what they're doing. So it's not merely the elaborateness of what's going on that guarantees the emergence of consciousness. For this reason, I think it is only certain types of functions that are associated with consciousness. It's not a graded thing. Final word from Susan Greenfield. Well, I think that it must be looked at holistically,

although like in any orchestra, some instruments might have more important parts than others. The other big, big issue, I think, are the chemicals. And until people look at the chemical basis for why people are happy and sad and relate that to consciousness, if they carry on with their silicon circuits just looking at learning a memory, then I think that's the wrong path. There you go. Thanks, Susan Greenfield, and congratulations on winning the Michael Fah. I'm a medal and Professor Ramachandran, whose book is called Phantoms in the Brain, Human Nature and the Architecture of the Mind.

Next week, my guests will be two historians, Linda Colley and Catherine Hall, and we'll be discussing the legacy of empire through the 20th century. And thank you for listening. We hope you've enjoyed this Radio 4 podcast. You can find hundreds of other programmes about history, science and philosophy at bbc.c.com.uk forward slash radio 4.