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29 Nov, 2019 07:00

Knowledge is Hydra - neuroscientist

The human mind, however beautiful it can be, remains a mystery. What is consciousness and can we even try to explain it? We talked about that with neuroscientist Baroness Susan Greenfield.

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Sophie Shevardnadze: Baroness Susan Greenfield, pleasure to have you on our programme.  

Susan Greenfield: It's a pleasure to be here.  

SS: We've spoken to some of most brilliant minds, and you're my first woman interview and I'm very excited to talk to you… 

SG: Thank you.  

SS: ...especially about the brain, because it seems to be the eternal topic. So you are very well-known, a respected neuroscientist, and you've covered many aspects of human brain and how it works and all of that. And I've talked to neuroscientists, and most of them tell me that we're very dual beings, that brain and body are two separate entities and one is governed by the other. They all seem to somehow stick to this theory. I wonder what you think. Are we two separate things? 

SG:Well, it's a rather strange image if the brain and the body are separate. You'd look a bit weird if that was the case. No, they're very integrated. If you think about it: the immune system, the endocrine, the hormone system are things that we have in common. So the placebo effect, for example, where you can take a drug that's completely inert, completely has nothing active in it, but you think it's going to make you better and it does - the so-called placebo effect - that has to work in conjunction, the central nervous system has to work in conjunction with the immune system and the endocrine system, the hormones, because otherwise you would have biological anarchy if they were separate. So there has to be a system for the brain and the body to be really integrated. And the brain, after all, is just another organ of the body, a very important organ, a very greedy organ in terms of energy, but nonetheless, it is an integral part of your body. It's not as if it's a separate little machine that's perched on top of the body directing like a little robot. No, of course not. You have the chemicals that are reiterating throughout your body from the great control systems of the body, and there are three of them: the central nervous system, the endocrine system and the autonomic nervous system which is controlling the heart.  

SS: I want to talk a bit about consciousness now because that's a huge topic for you and for all of us. What is consciousness from a neuroscientist point of view? Is it what makes us human? I mean, do animals have consciousness? 

SG: That's two separate questions. First of all, I think if we say- what scientists like to do is to say: “Let's take the null hypothesis, let's assume it's not the case.” So let's assume an animal is not conscious, right? When, and where, and how do suddenly you cross this magic line that suddenly gives you consciousness? Is a foetus conscious in the womb? If it is not (the null hypothesis!), when does it become conscious? Is it when it is going down the birth canal? Well, that's a bit tough, if you're born by caesarean section. Is it exactly at 40 weeks? Well, that's a bit tough: if the baby's born prematurely, is it not conscious? So the null hypothesis isn't really very robust. To say that things are not conscious is a bit of a risk because you then say, “If you look at animals or look at the foetus, what is the difference?” Because the human brain - although obviously, the parts may be exaggerated and different sizes compared to other animals - there's no magic brain region that's different in humans from other animals. So where do you cross this anatomical Rubicon? You can't. So I would reject that idea and say: “Let us assume all animals are conscious, right? Let us assume therefore a foetus is conscious.” But then that's a bit odd because are you really saying a rat is conscious like you or me? No? Obviously, no! So you say, “Well, let's think about consciousness a little bit”. And for me, my great insight: once - and I was on holiday - I suddenly thought this, I was thinking about unconsciousness. And with anaesthesia and with sleep - both forms of unconsciousness - it's gradual. You can have stages of sleep and stages of anaesthesia. You can have a different depth of being unconscious. And so, it reasons, what if consciousness also could vary like a dimmer switch - varying degree? If that was the case, a rat could be conscious, but not as conscious as a cat or a dog, and a cat or a dog could be conscious, but not as conscious as a primate, and a foetus could be conscious, but not as conscious as a full-term baby, in turn not as conscious as an adult. So if you think about that, that kind of makes sense, because I'm sure in Russian, you have the same things about broadening your consciousness or deepening your consciousness.  

SS: Yes.  

SG: You go to mountains or lakes... 

SS: Absolutely. 

SG: ...to either deepen or raise, doesn’t matter which way you go, your consciousness, yes? 

SS: Do you feel like we can sort of switch it off and all, like...  

SG: Gradually, it's gradual. So, for example… 

SS: When you're sleeping. Because I feel unconscious, I'm thinking my childhood over in my dreams, or the movies that I've seen before I switched off - is this consciousness? 

SG: Of course it's conscious. And dreaming is a form of consciousness. It's one, however, that isn't driven by inputs through your senses. So that's why it's rather flimsy and why you have this strange, fragmented sequences that at the time seem perfectly acceptable, but of course, in the cold light of reality, you seem really strange when someone turns into someone else or something happens. But yes, of course, that's a form of consciousness. So, I think, if one accepts that consciousness is quantitative, it can be varied - that's brilliant also for science, because you can then measure it, of course. You can say, “Let's try and measure it rather than regard it as something magical.” 

SS: But consciousness, the way we understand it - it's something totally intangible. We know somehow some functions of the brain. I'm sure there's a lot we don't know, but where the memories are stored and how things are going and signals and they're in it. But where does physically consciousness appear in the brain? 

SG:Okay. So this is why many scientists have a problem with consciousness. Someone called it a career-limiting move, if you want, just because you can't get grants or so on. The problem with studying consciousness is that quintessentially the core feature is subjective. What you are experiencing now, I have no idea. I can't hack into you and experience what you personally are feeling. The colour red - I don't know what you're experiencing when you look at the colour red. This is something called ‘qualia’. It is not that you can look at magic brain regions. The brain isn't composed of little mini-brains. So when you say “where memories are stored”, in a sense that's not quite right because you don't have magic brain regions or special brain compartments. But what you can do is try and find something, you have a shopping list and you go to the brain,  and you say, “Okay, brain, I've got this shopping list now. I want something that varies in degree. I want something that changes from sub-second to sub-second timescale, can vary. I want something that can be driven by the senses or generated internally.” And what we have done is suggested that it is collections of brain cells that work together for a very brief period of time, a bit like ripples. So imagine a puddle and throwing a stone. Then you have the ripples. And what we have done is to try and identify something like that happening in the brain where the excursion of the ripples corresponds to the depth of your consciousness. So if you're like I can say: the stone is like the alarm clock waking you up or it's like any strong sensory input coming in. And then the size of the stone is how many connections and associations that object or that event triggers. And the force with which it is thrown is how strong the sensory stimulus is. And then the way it spreads out is limited by the, we say, viscosity, which is the glueyness, if you like, the thickness of the puddle, and competing stones coming in. And what have done is to write a book…. I’ll plug the book “A Day in the Life of the Brain”, which was written in 2016, which go through with this and talks about this. So I think what scientists can do - we can start to study consciousness with great humility and assuming that we're not going to establish a causal relationship. I can't tell you how the water is turned into wine. I can't tell you how electrical blips in brain cells and chemicals trafficking, all that - I can't tell you how that translates into a feeling of happiness. But what I can do is to say, “Look, when you're happy this is happening. When these blips and electrical signals are firing away, then you might be feeling this.” Now, how the one turns into the other is the big question. And what I find interesting to say to people, I'll say it to you. 

SS: Do you feel like trying to explain what consciousness is - for scientists is like a fringe topic? Is it marginal, because it's so subjective? 

SG: What’s so important to realise for science is the thing that they need more than anything before they can do anything - is money. Because unlike something like philosophy, if you are a scientist by definition, you want to work in a lab, and that costs money. How do you get money? You get money either by starting a little company, as I have, incidentally, for Alzheimer's disease. I've gone to the private sector… Or you apply, if you're in a university, for grants. Now, if you apply for a grant saying you want to study consciousness, I can assure you: certainly, in the United Kingdom, you don't have much luck, which is why it's not popular with scientists, because it's very hard to get funding. It's very hard to get people to… They'll say, “Well, what we're going to do with this? How we're going to study it?” Whereas if you're studying some much more clear problem, then people will feel taxpayers money can pay for it.” 

SS: You mentioned philosophy and there is this play by Tom Stoppard literally called “The Hard Problem”. It is about what we're speaking. I'm sure, isn't it? It's about a researcher… 

SG: I haven't seen it, but I know what the hard problem is. 

SS: She’s trying to research it and just gives up, and then ends up in philosophy. Do you feel like philosophy could somehow help the scientific part? 

SG:  Well, I actually started doing philosophy myself. Initially at school, unlike probably all the other scientists, with the exception of Henry Marsh that you've interviewed, for my specialised subjects after 16, so-called A-levels, I did Latin, Greek, ancient history and maths, pure maths. The reason I did Ancient Greek was I was really interested in philosophy. When I first went up to Oxford, for my first year at Oxford University, I actually studied philosophy, and it was only when I got frustrated with doing formal logic, having done maths, that I changed to psychology and then to neuroscience. So I actually have - I would like to think - a grounding in philosophy or I see things as a philosopher might, and I think that's actually very helpful if you're doing science. 

SS: Does it help advance science? 

SG: Totally. Totally. Because you ask big questions. And I think, if someone has a conventional upbringing in science, you are so constrained by the dogma, you are so constrained by being very precise and very specific to actually step back and ask these big questions like the ancient Greeks asked. I found that was a great privilege to do that. 

SS: Okay. Let's talk about thought. We once again somehow know how the body and the brain interact, right? And correct me if I'm wrong. So here's my thought: I want to bend my finger, so send signal to my brain, then the muscles do the hard work. Where is the thought in all of this? 

SG: I think, where is the free will? 

SS: Or that. What I mean, is it born before? Is it somewhere between? 

SG: That's a really interesting subject. If you relate especially to free will and it's an endless debate of what is free will. Benjamin Libet had this idea, and I myself have done a copy of this experiment. I've been the subject where you have electrodes on your head which record your brainwaves, and all you have to do in this experiment is press a button whenever you want to - whenever you think you want to - and what's really interesting is just press a button randomly, is just before you actually physically press the button already your brainwaves have changed showing that. So it's a really fascinating thing that you think you have free will and you've decided but already your brain has changed beforehand.  

SS: It has decided before you.  

SG: This is the interesting thing. You are your brain. So to say “it has decided for you” is implying a certain dualism, which is not right. So this is why it's an interesting question.My own view is like two sides of the same coin. In quantum theory, which I'm not an expert in, I gather you can express things either in terms of momentum or position, but never both. It's like speaking Russian or English. You don't speak the two together. You have one or the other, but you might express the same idea.  

SS: Oh, I mix them quite a lot! 

SG: But for less fortunate people, you either say something in one language or in another. But you're saying the same thing! So it's two sides of the same coin that either you can express things in brain terms, or you can express it in subjective, what we say, phenomenological terms. That's to say in terms of your subjective experiences. And both are valid, and how the one relates... That’s like the position momentum - you can't do it simultaneously. Even you couldn't speak Russian and English exactly the same time - you'd have to switch very fast. So that's I think what it is like. And that's why it's so interesting because it's not so much about the thought itself, the subjective experience of a thought and the illusion of free will or the physical occurrences in the brain. It's more, “If there are two sides of the same coin, what is the coin?” That's the interesting question.  

SS: I just want to bring you back to the raw stuff, same with the consciousness until you gave me the ripples possible explanation, because if we know the brain, the frontal lobe answers for this, and this hemisphere for that, and that hemisphere for that. Why can't we physically observe the thought?  

SG:Because the brain doesn't work like a load of mini-brains. Yes, you do have specialisation in different parts of the brain, but it’s more analogous to instruments in an orchestra or ingredients in a dish of food. They have to synergise. They have to work together. It's not as if they're just functioning independently of each other. So, for example, vision is divided up among about 30 different brain regions, and any one brain region can participate in different functions. Rather like a violin might… You have to think of the brain holistically, and holistically I would argue in a body. You can't try and reduce it (as sometimes people like to do) to a single gene, or a single brain region, or a single transmitter. By that you're losing something if you do that. 

SS: So there is no way a thought could ever be observed, even if we build incredible machines? 

SG: What can be observed is the brain working. And of course that's done with brain scans and people could do that. But the mistake they often make is how they match up what they see in a brain scan with what is happening. Some people think that it's much more specific than it actually is, and they think that if they see something lighting up in a certain region, it's the centre for this or that. And that's not really true. Moreover, with brain scans in humans, the time resolution is a bit like… Do you remember those old cameras in the 19th century where you could see physical things but not movement? So you could see houses and a car, but you couldn't see animals or people because they were moving and the exposure was too [long]. So a little bit like that with brain scans: you can see long-lasting things, but you can't see fast things. 

SS:  You know, for many people who wouldn't be happy with the scientific explanation, because like you said, there is no way we can physically actually observe the thought or see the conscious where and how it's moving or born. They would say, that's all about the soul, and you'll never be able to see it. Because that part is called soul. 

SG: Okay. 

SS: So what do you make of that? 

SG: Okay. I think we need to be really clear about terms. Let's start with the most obvious one - brain. We all know what the brain is. It's a physical thing. And I remember doing dissection and wondering if I got it under my fingernail. Would that be the bit? So it’s a physical, tangible thing. Then you have the mind. Now, why do we use a different word for mind? Mind implies something highly personal. That's different. Your mind is different from mine, if you and I took our brains out, at a gross level, they would look pretty similar. So the mind is something that already is slightly removed from the physic of the brain. And to cut a long story short, my suggestion is that it's the personalisation of your brain. It's something called ‘plasticity’, which is how the brain adapts to things. And when it adapts to things at the very micro level, you're having changes in connections between your brain cells. So no two people have the same pattern of connections. That's what I would call the mind. Then we have consciousness. When you go to sleep, you don't say you're losing your mind - you lose consciousness, or there's certain scenarios that - don't you have the same say in Russian? - where you ‘blow your mind’ or ‘lose your mind’ or you're ‘out of your mind’ – you’re conscious, but you're not accessing your personal… 

SS: When I take ayahuasca or something like that? 

SG: Well, I'm sure in many ways in which you can… well, ‘wine, women and song’; ‘drugs, and sex and rock and roll’.  And what I found very interesting there is ‘mindless’. You're still conscious. Incidentally, even the ancient Greeks thought about this. There’s a play called “The Bacchae” by Euripides, all about this poor king, who gets torn apart by these women who are crazed worshipping the wine god Dionysus. And he says, “No, there's two forces: the wine force and the bread force.” Anyway, I digress. And to say how wonderful the Greeks were. So then there’s the mind and consciousness, which is separate again, because you can be mindless and have consciousness, and you can have no consciousness, but you still have got the mind. Now we come then finally, within consciousness, you have the subconscious and you have the self-conscious, and the self-conscious comes when you're about two or three years old. So a baby is conscious but not self-conscious, because on the continuum it’s varying. And you have the subconscious as anyone who has read Freud will be aware of. Then you have the soul. And that again is something that I would regard as separate because the mind and consciousness are all parts of a living brain. They're more than just the living brain, but they are rooted in the living brain. 

SS: Even the subconscious? 

SG: Even the subconscious. So when you die, the brain will die. But as far as I understand it, I'm not deeply religious myself, but I respect people who are, the whole point of the soul is it's immortal. Is it not? That's the whole point. The point of a soul is it survives - it goes to Heaven, or... So… 

SS: I mean, if you look at it the religious way… 

SG: Yes, exactly. So that's how you're defining soul.And if the brain is perishable and is mortal and the soul is immortal, then it must be something else again. Right? So I think one has to be very careful about one's terms and distinguish very carefully brain, mind, consciousness, soul. All are legitimate, interesting topics, but one shouldn't equate them. They are separate things. 

SS: So once again going to the scientific field, a lot of scientists try to explain different phenomena biologically. For instance, love or feelings. We're saying, “It's all hormones, it's dopamine or serotonin for you to be happy.” But when you explain that on a biological level and it stands ground, do you really explain what love is? 

SG: Again, it's not an explanation. It's a description. It's like saying, “A chair is a piece of furniture.” 

SS: Do you really describe what love is? If you say: “Oh, it's just the chemicals and hormones in your brain.” 

SG:I don't know if you're familiar with the Gestalt theory. Yes? So that's for people who are not. Imagine a straight line. Imagine a dot. Imagine half a circle. Imagine another dot, random things. If you put them in a certain shape, if you put the two dots at the top of your page and between them, you draw the straight line and underneath them you put the half circle - then you have a face. So the components are in and of themselves, not changed, but it's the relationship of the one to the other that has given you this concept of a face, a pattern of a face. So it’s like to say, “This is nothing but a dot, it's nothing but a straight line”. Depending on how it relates the one to the other, will give it a so-called ‘emergent property’, a different property to just the reduction of the components. 

SS: Because I was thinking, if you can explain or you make this distinction, explanation and description, can describe anything biologically, then you can just describe consciousness as well. 

SG: Well, you can give correlations. You can say, “When you fall in love, you have a rush of dopamine or a rush of endorphins.” That's fine. That is a correlate. But that doesn't explain why you have the subjective feeling of love. It doesn’t explain that. 

SS: OK, let's forget about love, because that's really a way too complex. Let’s take happiness, the state of happiness, when you have serotonin levels rising or dopamine. And for scientists, it's all hormones and it's all chemically sort of manageable. Does this mean that if I take a happy drug, and my serotonin levels go up and I feel happy, then happiness in itself is an illusion because you can control it chemically? 

SG:It depends on what you mean by happiness, of course. We all know that drugs, like heroin being the most obvious one, and the opiates, give people a feeling of euphoria. A feeling of euphoria is not necessarily happiness. You can pass an exam. You can achieve something you've been striving for. You can have a sense of well-being. All these are different types of positive feeling that people might put under the label ‘happiness’. And if we had a society just where people wanted to be euphoric all the time, I don't think we would find that a very satisfying lifestyle. You wouldn't really admire or want to be someone who was just all the time euphoric. 

SS: I think my question is more like chicken-and-egg. What happens first? I mean, is it the dopamine, and then I get happy? Or I’m happy and then the levels rise? 

SG: That’s an interesting question, especially in relation to depression, which is the opposite, of course, because we know that if someone's depressed, they can take Prozac, which enhances the levels of this chemical messenger: you've talked about serotonin. Then that alleviates their feeling. But if they're unhappy for a particular reason, it doesn't make the reason go away. If they've just lost someone they love, it doesn't bring that person back to life again. It just is a distraction for them. A bit like when people drink heavily. It's a distraction. That's not exactly to say that it's making you happy. It's distracting you. It's giving you a strong sense of being aroused or sedated. It's manipulating your arousal levels more than actually giving you what one might want to acquire in life in terms of what one would call true happiness. 

SS: I want to have your take on this, because the general idea is this big professionals in different fields would say, “Well, you know, science takes care of the biological processes because we can describe them or some would even say explain them, and then psychologists or psychiatrists, whatever, takes care of the psychological side: emotions and the way we sort of interact with the world on an intangible level.” But shouldn't we really just be studying it altogether, because this is just such one big mechanism, instead of dividing all up in bits and pieces? 

SG: I’d go further, Sophie, having arts done myself, having done philosophy, I think it's insane to distinguish philosophy from neuroscience or even from legal people. I’d like to talk to them about free will… So the more we can be interdisciplinary, I think, the richer it is. And I would go further in that people that are just neuroscientists- I'm just a neuroscientist, I wish I knew more immunology, for example. I'd like to know the interface between the central nervous system, and the endocrine system, and the immune system, because by understanding that you understand the placebo effect. You'll understand how your gut feelings (literally chemicals released in your gut) are affecting your sense of intuition. So I think that we are the poorer if we put ourselves into silos of just being this or just being that. 

SS: How much do you think we know about a human brain? In percentage. 

SG:Okay. So, from my Greek again. There was an animal called the Hydra. And every time you chopped off one head, seven heads grew in its place. And it's like that. The more you think you learn, the more you realise you don't. You and I - we’re both finding we had French in common. When I first went and started speaking French, I thought I could speak it, and the more I tried, the more I realised I didn't know. So the more you learn, the more you realise how ignorant you are. I feel like that with the brain. Yes, of course we can explain how brain cells fire little electrical blips, and of course, we can explain how chemicals go up and down and they’re manipulated by drugs. Of course we can explain those things. And now we can, of course, with brain imaging see bits lighting up. But I think it's extreme arrogance if we think that means that we know everything, because what we should be doing is really asking the big questions like what is consciousness? Why do people fall in love? Why do wars start? Brexit - how does that happen? Sorry, it’s a joke. That’s the biggest mystery of all! 

SS: I don't think we have the interview time for that. Anyway, thank you so much for this wonderful insight. I hope we’ll meet again.

SG: My pleasure. Thank you.