In Our Time - Neuroscience

Episode Date: November 13, 2008

Melvyn Bragg and guests examine the relationship between the mind and the brain as they discuss recent developments in Neuroscience. In the mid-19th century a doctor had a patient who had suffered a stroke. The patient was unable to speak save for one word. The word was ‘Tan’ which became his name. When Tan died, the doctor discovered damage to the left side of his brain and concluded that the ability to speak was housed there. This is how neuroscience used to work – by examining the dead or investigating the damaged – but now things have changed. Imaging machines and other technologies enable us to see the active brain in everyday life, to observe the activation of its cells and the mass firing of its neuron batteries. Our extraordinary new knowledge of how the brain works has challenged concepts of free will and consciousness and opened up new ways of understanding the brain. Yet these new ideas seem to conform to some old ideas such as Freudian Psychoanalysis. But what picture of the brain has emerged, how has our understanding of it changed and what are the implications for understanding that most mysterious and significant of all phenomena – the human mind?With Martin Conway, Professor of Psychology at the University of Leeds; Gemma Calvert, Professor of Applied Neuroimaging at WMG, University of Warwick and David Papineau, Professor of Philosophy of Science at King’s College London.

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For more details about In Our Time and for our terms of use, please go to BBC.co.com.uk forward slash radio 4. I hope you enjoy the program. Hello, in the mid-19th century, a doctor had a patient who had suffered a stroke. The patient was unable to speak, say, for one word, the word was tan, which became his name. When tan died, the doctor discovered damage to the left side of his brain, and concluded that the ability to speak was housed there. That's how neuroscience used to work by examining the dead

or investigating any of the damaged. But now things have changed. Imaging machines and other technologies enable us to see the active brain in everyday life to observe the activation of its cells and the mass firing of its neuron batteries. But what picture of the brain has emerged? How has our understanding of it changed?

And what are the implications for understanding that most mysterious and significant of all phenomena, the human mind? With me to discuss neuroscience at David Papineau, Professor of Philosophy of Science at King's College London. Gemma Calvin, Professor of Applied Neuroimaging at Warwick Manufacturing Group University of Warwick and Martin Conway, Professor of Psychology at the University of Leeds.

Martin Conway, can you just say what is neuroscience and what its principal aim is? That's a bit of a big question, but neuroscience really is a kind of a confederation of different disciplines centered around an ambition to create theories which extend from the neuronal and neurobiological level right up to the cognitive and cultural levels in understanding the human mind. And I think it's really been stimulated massively by innovations in imaging, neuroimaging, as it's called. And as you mentioned, our ability to put people in scanners, get them to perform cognitive. tasks or even emotional tasks

and see which parts of their brain light up. That's been a central technological innovation that's helped this area pull together. But the area itself is as I said a confederation. It covers people who work with animals, for example, cognitive scientists, artificial

intelligence modelers and chemists, even physicists are involved in helping us create the techniques we need to examine the brain in action. When he did get going as a science, as a discipline even? Well, I'd say it's fairly recent, actually.

I mean, other people might have other views, but I'd say the term neuroscience really started to emerge in the mid-1990s. I mean, it was around before then, of course. But there was a book by a man called Yap Panskeep in 1997 called Effective Neuroscience, which was about studying very basic parts of the brain that modulated basic emotion. and I think that would be a good point to say around about 1997 issues, so neuroscience studies who emerged as a more coherent field.

Did he have precursors in the persons of, say, Alzheimer in the late 19th, Adice Alzheimer and Sigmund Freud as an early neuroscientist? Oh, absolutely. Well, Freud, of course, was one of the leading neuroscientists of the 19th century. He wrote a famous book on Ephesia, actually, which is still used by people. and his original thinking about how the mind was neurobiological. In fact, he wrote a thing called a project for scientific psychology, which is his first major work, which he then destroyed, but he sent a coffee to a friend, and it was discovered after his death.

And he, in fact, abandoned the project because he felt in the 19th century, we didn't have good enough biological knowledge to model the mind in that way. And in fact, there's now a new area called neuropsychoanalysis, which is taking a lot of Freud's ideas and reapplying them, given we now have a better understanding of the biology of the brain. And why was he dissatisfied with this work? I mean, rather like Francis Bacon used to destroy the paintings he didn't like. Freud seems to have destroyed the papers that he didn't think came up to his own standards.

Well, Freud frequently did that. I mean, he wrote a famous paper on consciousness that is hinted out in his work, at which he destroyed, and everybody wishes they could get their hands on it. I think he was a bit of a perfectionist and he wanted to make sure that what he wrote reached his high standards of, you know. But what he said then is consonant with what is happening now. Why do you think it's a very good time for neuroscientists

and for us to be talking about neuroscience now? Well, I think because we're now beginning to understand some of the basic processes in the brain and how they work, understanding things about basic aspects of the cell, for example, how the older brain contains many circuits which clearly mediate some of our basic emotions like rage, approach, seeking, attachment, etc., and how those emotions are modulated by higher-order neocortical levels. So we're making progress in those directions,

you can clearly see how that would relate to the thinking of Freud in particular, but also other 19th century neuroscientists. Jennifer Calvert, as a neuroimaging specialist, can you describe some of the techniques that you use and what you discover with these techniques? So first of all, what are these techniques? Well, we have a range of techniques available to us now. Obviously in the 1930s, electroencephalography or EEG had been developed, which allows us to record electrical signals in real time coming from the brain. But it's rather difficult to localise where those signals are coming from. So in the 70s and subsequently early 80s, we had a technology available to us called Positron emission tomography or pet.

And this allowed us to begin to see the working of the human mind in, again, in real time, but involved injection of a radioactive substance. So not ideal for doing sort of mainstream experiments. and more recently we've now got technology which is probably the method of choice for cognitive neuroscientists called functional magnetic resonance imaging and this involves using a standard MRI scanner which you'll probably be aware of in order to take it can take pictures of the body and pictures of the brain

structurally but it's been upgraded in order to take images of the brain much more quickly consistent with the fact that we want to look at brain function. So an MRI scanner is a large magnet And it's about 40,000 times stronger than the Earth's magnetic field So when you're lying in there, we're able to Show you different types of images

Or present fragrances or foods and so forth And see which bits of the brain are actually involved in the task So in that sense, you're mapping How, just before we go on, how far in advance are these techniques From the techniques available, say to Freud, say 100 years ago? Oh, enormous, enormous advances. All this resulted really in the 90s being called the decade of the brain, and I think we're really looking actually at the century of the brain.

Being able to see inside the human mind has begun to show us just how much of our processing can occur below the level of our awareness, for example. It's interesting, yet again, a huge hours of knowledge of technology driven because of the technology we can go into, perhaps the most important area of all. That's absolutely fast. Can you give us some one or two specific examples, Jim? I'm sure our listeners are like, now, if you do this, this happens, this shows this part of brain. That's Greenland, that's Australia.

We're now finding a bit more about Africa, that sort of mapping. Well, of course, you're asking about the spatial resolution of these techniques, and we're able to, obviously, map areas of sensory cortex, so we know about where the auditory and visual areas are, and we can start to. We know all about, I mean, seriously, I'm so stopping. Absolutely. So you could put people in this and you say, we know, what does it all about that mean? Well, we can see the stages of processing, particularly if we combine techniques like EEG with functional MRI,

we can actually resolve not where things are happening, but also the time course of that. So we can see, for example, that if you're looking at an object, you see early visual areas coding for the coarse-grained information, like the colour, the shape, location. and then as you move forward into the brain into the inferior temporal cortex, you can see areas which are specialized for processing faces, for example, compared to places or objects. But not just that. We're beginning to build a database, if you like,

of really more complex social constructs, such as where morality sits in the brain, areas which are involved perhaps in religious belief. We're just beginning to sort of push at the frontiers. You think you'll find a part sort of, let's keep using the word map because it's easy. It's not too, it's not too bad an analogy. Whereas there sits the religious, that is the religious place, space. Well, typically with these kinds of questions, we tend to resolve them by explaining that it's never usually a single area.

It's a network of areas. So different parts of the brain coordinate their activity, often in, you know, synchronized fashion, to produce the experience that we, that we have, you know, our conscious perception. Before we move on, just one even more specific thing. You've been looking, as I understand, at something called grandmother cells. Can you be specific, can you tell us a bit about the grandmother cells? It's such a nice phrase, we can't let it pass by.

Well, I don't think there's a sort of cell with a big G on it, if you like, said called grandmother. That would be a help. I think the terminology really derives from single-cell recording where you're using electrodes to record in monkeys, for example, because it's an invasive technique, the activity of individual cells. And what you can see is that some cells, they will fire to numerous different types of faces,

but maximally so to an image of your grandmother, for example. But it's not to say that the representation of your grandmother is coded in that cell and only that cell. So this is when you say firing, this is an electrical... Excuse me. Yeah, it's electrical impulse. And there are billions of these going on in our minds all the time. Yeah.

Yes. So we're firing away as we're talking. But grandma is the recognition, the word, the idea of grandmother fires these particular cells in this particular place. Exactly right. But it will be distributed across a few cells. Obviously, otherwise if that cell died, you know, out goes grandmother. David, Papa, now I understand that one of the discoveries from recent New Roambium is that conscious thought plays a much smaller part in day of life. and we'd previously thought.

Can you deliver that? James Gema touched on that. She said that one rather surprising result, a lot of recent neuroscientific research, is a lot less of what we might have thought was conscious, really is conscious. And, I mean, here's one very famous example, is Benjamin Liebert's experiments on so-called free-will experiments.

You might have... What he did is he got some subjects, some people, and put them in the laboratory, and said, all I want you to do is press a button after a while, and we'll see when you press the button. But he also had a huge stopwatch on the wall, and he said, please note the exact moment when you decide to press the button. So that's finally pressed the button.

He also had some electrodes on the attached desk up so he could see, and the surprising thing is that the brain started the process that moves the finger quite a while before the subjects were aware they decided. I mean, about a fifth of a second, which is quite a lot in neuroscientific. So it looks like the brain has decided to move your finger, and only afterwards you become conscious of the fact that your brain has decided this. Because, as it were, received common sense would say,

I decide to move my finger to bang the table. I consciously decide, exactly. But I am not consciously deciding. No, your consciousness looks like it's kind of taking note later on of what the brain's already decided. Can you say a bit more about that? Because it's fascinating. I'm sure people all around this land are tapping their fingers on the television.

label and say, I decide to do that. They're saying, that's my decision. No, it looks like what's going on here is the conscious bit of the brain is keeping track of the decisions that have already been made by the unconscious bit of the brain. Look, this is a controversial, I mean, exactly how to interpret the experiment and it's only a fifth of a second and so on. But let me give you another example. This is to do with vision and the various pathways that, again, Gemma was gesturing at. So it looks like the process of visual information, processing of visual information, involves two pathways in the brain. There's the what pathway, which helps us to recognize kinds of objects. Is it a corkscrew? Is it a car?

Is it a whatever? And the wear pathway, which is just to do with identifying shapes in relation to the body. And, I mean, here's one thing that shows the difference. Think about visual illusions, those kind of patterns, where one line looks bent when it's really straight or two shapes, one looks bigger than the other because of the surroundings, even though they're exactly the same shapes. So consciously, the two shapes look different sizes.

But when we grab out for them, our fingers treat them as the same size. And what that suggests is that the conscious bit is subject to the illusion, but what's actually controlling our fingers is the unconscious bit of the brain that isn't subject to the illusion. And you can find subjects who've lost the conscious bit. They say we're blind, we can't see anything, but they can grab and reach objects perfectly well. So the unconscious brain is controlling the movements of your hands,

very striking. And from what I've read of what you've written, the unconscious is controlling a great deal. Freud has mentioned earlier in the discussion and his ideas about the unconscious, and many of us have the experience of going to sleep with a problem and waking up with something of a solution, and we say, ah, the unconscious sorted out,

that was a good night's sleep. But you're saying the unconscious is at work through most of the day, as well. In fact, the mass of what we do and what we're doing now is unconscious. And the conscious part of our brain is not only much smaller than we thought but much more specialised. Now, I think that's

fascinating. Can you develop that a bit? Well, it's an interesting question. What does the conscious bit do? I mean, if, looking at the kind of examples I've discussed, just discussed, it looks like it's just a bookkeeping operation. It's keeping track of what decisions were made. It's keeping track

of what objects were around kind of in objective space. It's probably building up life history. This is Martin's subject. It's keeping track of where you were when and where other people were in relation to you. But you might think what is all this bookkeeping for? I mean, and there must be an answer to this, and it seems that what the conscious part of the brain,

a small conscious part of the brain, is for is high-level planning. I mean, so should I go fishing tomorrow or should I? go and mug up on neuroscience. And if I'm going fishing, I better go and... At some point when the opportunity arrives, go and buy some fish hooks,

but if I should go to the library. And so you structure a sequence of plans. And I think that's the kind of thing that the conscious brain does. High-level planning, organizing your time. Sort of management. Yeah, yeah. I think, Conner, can we just take a step back a while?

Maybe like a few billion years. I understand that the brain can be thought of as a series of brains It can be looked off as it were the cities of Troy But with two principal brains Can you give us some idea of the two brains And why it's brain on brain and where the cortex comes in And what we're thinking about that Well, excuse me, the model is called the triune brain

And it actually distinguishes three kind of different layers If you want in the brain itself One layer would be the kind of brain stare man structures just above it, and that's sometimes referred to as the reptilian brain. So your average crocodile would have that sort of brain. And what does that control? That controls motor movement. It has a very basic circuits in it for modelling the body,

so basic fundamental self, if you want. It has circuits in it that control things like seeking, rage, attack. Appetite. So basic functions. And we all have that. We all have that. So we're all sitting with four reptile brains around the table as we live and breathe. Thank you, Jeremy.

Then on top of that, so the theory goes, is what's called the old mammalian brain. So this is an area of the brain that's kind of on the base towards the middle and slightly above that. The limbic system is sometimes called. This has structures in it which mediate the encoding of, new memories, new knowledge. It has stretches in it that perhaps control more sophisticated emotions

than the basic emotions. And then on top of that is the neocortex. And the neocortex is evolutionary, the most recent development. What's important about the neocortex really is how much neocortex one has in relationship to the rest of the brain. It's your encephalization quotient, it's called, if you want. and humans have the most. And this actually begins in the fetus, as I understand.

It does, yes. This is great division, that we have two tubes, one which becomes the crocodile brine and one which becomes the neocortex brain. Yes, in this fetus, a structure develops that's called the neural tube. And it's from the neural tube that the brain itself is going to be generating. Now, the way the brain's generated is absolutely fascinating.

There are two areas in the neural tube of what's called epigenesis, neurogenesis, and that just means they're the areas that generate new neurons and these neurons pass out and form layers, and then another wave of them come out and form layers. And it seems that one of these areas of neurogenesis wires up the brainstem and the reptilian brain,

and the other area wires up the old mammalian brain and the neocortex. So, one might want to say maybe one of these is a later evolutionary development. Jeremy Calvin, sorry, with your imaging techniques, can you see this you see these different sorts of brains.

It's like seeing layers, and if so, can you tell us what they look like and what they are like? It's not really seeing layers. You can see the whole brain in absolutely exquisite resolution using structural MRI. You, of course, can image the limbic systems. You can see the mid-brain, hind brain and the neocortex. But the advantage of being able to do functional neural imaging is you can now define what all these areas actually do and how they're specialized.

And we can compare that, for example, with the functions that these areas perform in reptiles and lower mammals. So what would happen if you could strip off the neocortex? How would we function? Would we function like crocodiles or would we, what would happen now? When you say later addition, you think it came, the neocortex came in when, Jena? Well, the layers, even within the cortic.

mantle, if you like. So, you know, from rabbits up to cats, up the phylogenetic scale, you are seeing expansion of the cortex and more cortical tissue, if you like, so that we're sort of top of the tree

up there with the dolphin, I think. And what we, I suppose if you removed the cortex, broadly speaking, we'd still be able to perform some simple behaviours, we, of course, all our

autonomic functions would continue. But we obviously probably wouldn't be able to use, we wouldn't have language and we wouldn't therefore be able to reflect on our thoughts or, you know, do things which actually make us human.

David Pavanagh, there's been a, a lot of people have thought for a long time, the difference between the soul and the body, but I don't think that quite figures in this discussion, but the difference between the mind and the brain, that a brain which is the porridge, which does the stuff, and there's a mind which has these thoughts which come from we know not what

and go we know not where, but these are distinction. Now, this seems to me the more that Gemma examines it and more that Martin examines his way, you think this is not on. It's a very natural way to think, to think there's all this grey matter, all this physical stuff, all these nerves, and then, in addition, somehow, floating above it is our conscious being.

Why do we want to think that? Because we wanted to think that for a long time. Very good question. I mean, this is my subject, and I'm a dyed-in-the-wall materialist. There's just one thing there. There's no extra mind stuff. But even I find myself, when I think about this,

it's a natural way to think that there's this extra, extra feeling bit. And there's a very interesting, the Yale psychologist Paul Bloom, has a very interesting theory. He's written a book called, Descartes' baby, which I think is there's some horrible story about Descartes had a still all child. But the main point is that all babies grow up as Cartesian from a very early age.

They're dueless. They think there's a mind that's quite separate from the brain. And his theory is that we have two different systems in the brain, one for dealing with people, beings with intentions, when we think about other people in their minds, and another for dealing with bodies, and somehow we put things in one category or the other. And he says, That's why it's so easy for us to understand the idea that somebody else's mind might come in and take over your body. I mean, think of this movie with Steve Martin, all of me, and Lily Tomlin, and by the end of the film, the person in control of the body is switching five times a minute. And when you're watching it, you have no difficulty understanding this.

And clearly, we think of the mind at something. But you don't. Well, we all think like this. No, we think like this. But I think that we all think like this. But it's a mistake. It's a mistake. What I'm... That should I've said.

You really don't. You think that is, so tell us what you think and why you think it's all. I think we should all think that's a mistake. Though, of course, neuroscientists often slip into talking in dualist ways. But the trouble with the dualist picture is that it leaves the mind with really nothing to do. I mean, we were talking a moment ago. It's not quite clear what the conscious bit of the brain does, but after a while we think, well, we can figure out something in it does. But if the mind were really separate from the brain, then it would be very hard to see how it did anything.

Because I think we all agree. even when we're slipping into this deulous way of thinking, the brain has all the material needed to control our bodies. And in fact, you don't need to look outside the brain to see why we're moving as we do. And the idea that somehow something else, some magic force comes in from outside and affects the brain, none of us think that.

So if we thought there was something extra, we wouldn't think it made any difference, and that would be a very muddly way of thinking. Martin Conroy, you're itching to take this up. Well, I think, no, I don't have to disagree with it at all. I agree with them, aren't you? But I think one way we might think about this is that we all have what's called a theory of mind. So I assume that your mind is rather like my mind.

And it may not be, but I assume it. And it might be that there's something like that, which is at the basis of our belief in a mind that's independent of the brain. That's been serious. And it's quite interesting. I mean, it turns out that if you don't develop a theory of mind, there are bad consequences. Autistic children often don't have a theory of mind.

They can't figure out that you will behave like they behave, for example. So it's a very fundamental thing, this theory of mind. And actually, people have a lot of the brain basis of it as well. So in fact, you're just looking, it could be like one of those trick pictures that you look at one way and you look at another. Now it's the brain, you're looking at the same thing, and now it's the mind.

But it is the same thing. It's an illustration you give. And then David is, there was these two conferences, one about Mark Twain and one about Samuel Clemens, and they discovered later on, they're talking about the same. Yes, yeah. And so you think that's what we're on. But the puzzling, I mean, that's exactly the,

the way to look at it. We have two ways of thinking about what's the same thing. We can think about it in terms of what it feels, using our theory of mind, or we can think about it physically, but we're thinking about the same thing. But the puzzle that we were worrying about is, why is it so hard to accept they really are the same thing?

When you discover Mark Twain and Samuel Clemens, you think, all right, there it is. There's just one person. We thought there were two, now there's one. But even after we get all the evidence that there really can't be an extra thing, we still go on feeling so strongly that it must be separate.

It can't just be brain matter. You're being much more tentative in what you're saying now than what you're saying in the notes of yours are bred away. You say, look, the fact is that the brain does it all. Being conscious is what the brain is, being imaginative is what the brain is, and this is what the brain does. That's what being a brain means. And the rest is nothing, really. The rest is a way of thinking about it in order to enable us to get through things that we want to get through, you know, with obstacles we go around.

But actually, that's it. How do you find that, Jim McAarver? This business has stuff hardwired in as well. Well, there's two questions there. I certainly subscribe to David's view that the brain and the mind are one and the same thing. I think it might be kind of useful just to think about perhaps different types of consciousness. So we all have the experience of being online, if you like. But then there's a sort of extra component which allows us to think about our thoughts.

So sort of meta represent. And I think that's something which perhaps maybe only humans have. So we have a kind of higher consciousness to other animals. So it's not to suggest that because you can't do that, you're not conscious because, you know, obviously we are. And if you've ever had the experience, have you come across the guerrilla illusion? This is fantastic. So you're watching two teams play basketball. And you're told to concentrate on the team that's wearing white t-shirts and count.

the number of passes. And at the end of this, you watch this movie, and the experimental will say, so that's great, how many passes, and you'll go, I don't know, 16. Well, did you see the gorilla that walked through the middle and sort of like waved at you? And they go, no, no.

Now, what's fascinating is when you then play it back, everyone can't believe it. There was a gorilla, and it really walked right in the middle of the scene, and you don't see it. And what's very interesting is that you're conscious, obviously, because you're conscious of coding, the number of passes. But clearly you're not conscious in some level of this gorilla that walks right across the scene.

And yet, what we're seeing with brain imaging is that in certain circumstances, we can see that the brain picks that up even though you're not conscious of it. So I think does that complicate the matter a little bit. It does, it's interesting. I mean, it's terrific. I'm trying to think, yeah. So what does it do? First time, I shook my head when it said, do I do I know that?

I didn't. I know it now. This is another example of how little of what's going on in the brain is conscious. Clearly, that the gorilla is impinging on your retina, and there's a lot of visual processing. It's taking note of the griller. But in terms of what you're self-aware of, what you think of yourself as seeing,

you don't recognise that you see the gorilla. In the sense, what you could say, the question there is, does the conscience have much to do at all? Well, I think we're all agreed. It has much less to do than we might pre-theoretically. have supposed, but it does still have something to do. It has this higher level planning to do. And... If you're not conscious, then you're counter. But, I mean, there's a rather interesting issue here which Gemma was touching on.

Look, take beings who don't have this higher level bit that we have, that we, that's a bit where we're sure, we're conscious, like children or cows or quite high level, I mean, surely children, infants, I mean, one year old, I mean, six months old. do we conclude that they're not conscious? That doesn't look right. It looks like they've got a kind of consciousness, but it's not the kind of consciousness that we're aware of when we've got this high-level thing.

And when the things go on in us that go on in them, and if we can manipulate things to focus on that, and we ask us, will we be conscious of that? We say, no, we weren't conscious. But at the same time, I want to feel that if we didn't have this high-level consciousness, then the stuff going on that we share with the neonates would be conscious. But we deny that it's conscious when somebody asks us. It's a very difficult thing to figure out.

Is it you satisfied Martin Conway? No, well, I mean, the question is, are there other bits of consciousness in the brain that we aren't aware of? I mean, that seems to be the implication. Unconscious consciousness. Well, that sounds like a ridiculous contradiction, doesn't it? It does really. I was just thinking when you were talking, David,

it is more complicated than we think. And you think about these famous studies that were done recently with patients who are actually, who are actually in comas and you put them in a scanner and scan them and you say to them, imagine you're serving a tennis ball in a tennis match. Then the brain areas that light up in the comatose patient are the same as the brain areas

that light up in the conscious patient when you ask them to do the same thing. So these comatose patients are in deep coma and have usually been in for many weeks. Their brains, obviously unconscious brains, are still functioning like conscious brains, even for complex motor movements, like doing a serve at tennis. So I think the situation's actually even more complicated than we imagine.

So what does that tell us? Well, I think what he tells us is that really complicated parts of the brain can function without consciousness. And that then raises the question, which is the question you're after here, I think, which is what is the function of consciousness? And the fact of the matter is this is called the hard problem, and we don't know the answer. No, that's not the hard, the hard problem. I think it's too easy to get muddled up. with what's, we're pretty clear,

which is a conscious bit of the brain, it's right in the front, it's involved with classification, keeping records and planning. And if you want to know what that bit of the brain does, well, I've just told you it's to do with keeping records and planning.

If you then slip into thinking, oh, but there's this extra non-physical bit the mind stuff, and what does that do? Well, now that's the hard problem, and the answer is, your confuse there isn't really an extra non-physical bit. So I think that once one avoids

getting sucked into this dualist illusion, then there isn't a hard problem anymore. The hard problem is only manufactured by bad philosophical thinking. But surely, the hard problem remains, the problem of what is consciousness and why is it there? Well, that's... Let Gemma come in with the imaging and the... I was going to say,

I think it's not necessarily the case that consciousness is represented in a single part of the brain. I know there are some studies suggesting there's a link between the frontal... parietal area and when that becomes active, then we sort of, you know, it's consistent with us reporting an experience. But that's not always the case and it's not necessary or sufficient. So there are other studies, you know, you're referring to these ambiguous illusions where you either see two faces or silhouettes or a vase, which is made up within the silhouette. And what's

very interesting from studies in monkeys and also brain imaging is that, obviously you flip, well we don't know why particularly that you flip from one. You can't see both, but as you do so, the cells which are either face cells start to fire, and that's linked and locked in time with your perception of face. And as soon as you start seeing the vase, it's the areas that or cells that code the vars that become active. So we've got a sort of time-locked relationship between your experience and the firing rate of cells. When you examine in detail, and I think let's go back to these word maps, when you examine this in detail and find more and more about this things,

and obviously it just started a few years ago at the start of what could go on. You said the 21st century could be the century of the brain. Do you think that one can see very good medical results coming out of this? Are there areas in which you think that people can begin to use this for control, for reorganising, for interfering? Well, I think some of the most interesting uses of this technique has been in the area of mental health and mental disorders because, you know, doctors and psychiatrists are often faced with the problem that there's no kind of physical instantiation of hearing voices, for example. And so they've only got sort of symptoms to go on.

It's, you know, you have to sort of trust that the patient's telling you that that's the case. But with brain imaging, we can see that, for example, when some schizophrenic patients hear, hear voices, their auditory cortex is actually stimulated, you know, and becomes active. They are hearing voice. Yeah, they are hearing voices. Martin. No, I think that's exactly right. It's real.

You couldn't have, you couldn't hear a voice in your mind, if I'm allowed to use that word, without the appropriate part of the brain becoming active. It wouldn't be possible. You see what I mean? So on schizophrenic, hears a voice. We call it an hallucination, an auditory hallucination. but in fact they're hearing the voice. It's just like you hearing a voice.

So what are these, what is this adding up to with your mind-braining, David Koppina? I don't think any of this really gives us any reason to suppose that the mind is separate, separate from the brain. I mean, it's giving us lots and lots of interesting information about the way the brain works. I mean, I like the thing about the hallucination.

It's very similar to the fact that if you ask somebody to imagine, imagine seeing something red, imagine a square, the same bit of their brain becomes active as when they actually see something red, they actually see a square. Because if you ask people to remember something from the past and they actually do get a memory in mind, or to imagine something from the past, the same brain areas like that. Is there a memory centre of the brain?

I mean, memory given that we all live by, giving to our own history, given what happens to some of us in old age, because of the pauling away of memories. Is there a memory centre? Maybe I should ask that, Gemma, first and ask you to comment on it. Yeah. Then you...

Again, it's a question of networks of areas. So the hippocampus, for example, is a small structure involved in encoding memories, and then there are parts of the frontal cortex, which is what Martin works on, which are involved in retrieving memories and extending them

into a larger storage base. I don't entirely agree with that. I mean, the near imaging data suggests that whole areas of the brain light up over time as you retrieve a memory. And I tend to think about it as the brain sort of breathing a memory in a sense. It's all being taken up.

But there are other areas which are very important as well. Hippocampus is absolutely critical in encoding you information. And if you have damaged your hippocampus, you become amnesic and you can't. I think code new information, but the whole area of the temporal lobes,

which is an area kind of sort of behind your ears and up a bit and down a bit, is a really, really interesting area of the brain. It's an area that generates lots of very, very interesting feelings, for example, when you remember you feel things. You feel like a memory. He doesn't feel like something else. You mean feeling feels like a feeling?

Yeah. A memory feeling. Yeah, exactly. We call it recollectal experience, actually. but there were famous studies done by Wilde Penfield back in the 50s and 60s, which continued to be done, where people who have intractable epilepsy, the only real treatment for them is to go in and cut out the bit of the brain where the electrical storm generates from.

That's usually in the temporal lobes. Can we be that precise? I mean, like cutting off a bad bit of flesh or something like that? No, we can these days. And actually they don't cut it out, they're going in and they just have a little tube and it just sucks out a bit of bone material. And that usually cues the epilepsy, not always, but usually. But prior to doing that, to make sure you don't damage other areas which are crucial, people electrically map.

So you can open up the brain. Of course, the brain itself has no neurons in. They can feel things. So you can stick electrodes in and ask what's happening to the person. But it's not going to hurt anybody. No. And you can intellectually map. So you put an electrode in, put a little current in.

And so, well, what's happening in your brain now? And they will tell you really, very interesting things. I've got a feeling of deja vu. I feel strange. I can see a woman. You know, they're really, really interesting responses. in this area, the temporal lobes, I think it's a really, really fascinating brain area. Sorry, David.

I want to press Martin a bit. I'm slightly surprised that you think there's such a hard problem in figuring out what the higher conscious parts of the brain do, especially given your line of business. Because one very striking thing about humans as opposed to our animals is we spend all this time building up a history of what's been happening to ourselves and all the people around us. I mean, it's a very complicated business.

We are constructing our life story. all the time. We're getting information feeding it in. What's that good for? I mean, it's pretty clear what it's good for. It enables us to manage our way around the world later on. But isn't that what the higher part is for? Well, it's one of the things it's for. I mean, there's things as well. I mean, I think the big difference

and this fits with your view, this is one of mine hypotheses, is that we have long-term goals. Most animals don't. They just have short-term goals, right? And probably our consciousness and the hugely developed frontal systems that we have in our brain

are there to allow us to have these long-term goals. The long-term goals are really the things that allow us to function as social beings in groups and make co-operative actions. And long-term goals involve structures as well. I mean, my example, I'm going to go fishing. Well, that's an intention, but nothing happens yet. So what I need to do various things. And so the next opportunity arrives, I'll buy some fish hooks.

and then I might turn that over to the lower part, but before that I've got to structure a whole sequence of operations, and that's a very complicated thing that requires higher organisation. Sorry, can I ask you, Jemma, I'm coming to end now, and people talking about what you've learned from this imaging, can you build up parts of the brain by taking, I was worth to say by taking thought. I've talked to, a lot of actors, for instance,

talk about the memories of muscle, They can build it up, and we have some remarkable actors in this country and elsewhere who can remember enormous chunks of things. The rest of the thing you can't remember the whole of that. Have you any evidence of the brain if we pay attention to it? We can develop certain parts of the brain, like we can develop certain parts of the body. Well, I'm not familiar with the large literature on plasticity. I know that obviously some people are making a lot of money with these brain-trained, you know, brain-trained. games, that's for sure. I think I missed a trick there. But for sure, to me, the brain is

kind of like another muscle, so the more you actually use it, and there is evidence that this is the case, the more you use it, the better it becomes. So in terms of you can sort of enhance your memory and, you know, and improve your vocabulary. And you can, you know, of course, you're learning. And the brain continues to learn throughout our lives. You learn to taxi drivers. That's a good one, isn't it? They did a study of London taxi drivers who have... There's a volumetric study of the science of the hippocampus, and they tend to have slightly larger hippocampire than other people,

and that's because they have to memorize the whole spatial layout of London, for example. So I do. The plasticity thing that the genoa passed by is very interesting. One's inclined to think, given that in normal people, all these different things gone in very special places we can see it in the imaging, that somehow the brain is all terribly hardwired, it's all determined to work like that. But surprisingly, if you cut out a piece of the brain at an early stage,

the same structures will grow somewhere else. And somehow the brain grows in response to stimulation, puts the things in a natural place if all the brain is there, but can put them somewhere else if the brain gets messed up. For example, if you're blind, those areas of the visual cortex become recruited by the auditory cortex and tactile areas. Cortical remapping, they call it, don't they? Actually, it's a really fascinating study on that, isn't it?

there's a neuroscience-based study with blind people where they created a sensor that they put on the tongue, and the sensor could stimulate neurons in the tongue, which connect up to the hippocampus and other areas in the brain. And this sensor would respond to sound. So blind people can walk around, and they have a thing that echolocates, basically. That triggers the sensor, and then they spatially map the room.

Well, thank you very much indeed, Jeremy Calvert, Martin Conway, and David Pepinow. And next week we'll be talking in the Baroque in European. culture. Thanks 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.com. UK forward slash radio 4.