Love, hate, and our brightest ideas – all born in the body’s most fascinating and complex organ. We talked to a man who literally looks into other people’s brains – Dr. Henry Marsh, one of Britain’s top neurosurgeons.
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Sophie Shevardnadze: Dr. Henry Marsh. Great pleasure to be here with you in your wonderful, lovely home. Thanks for having us.
Henry Marsh: Pleasure.
READFULLTEXT
SS: So I’ve got all the big questions. First of all, I know that you’ve said something like “In medicine, in general, you can never really be too certain.” I mean, it’s like if you go to a general practitioner he prescribes you drug and let's see, maybe it works and if it doesn't, then he’d try another drug. But with cut-and-try it wouldn't quite work that way, would it?
HM: As doctors we deal in probabilities. Nothing is ever certain. As a surgeon and obviously as a neurosurgeon what I do is not representative of all of medicine. If you recommend surgery to somebody, what you're saying is “the probability of the operation doing more good than harm is a bit better than the probability of your coming to harm if you don’t do the operation”. But these are probabilities. So let's say, I say “Well, there's a 95 per cent chance the operation will be successful removing a difficult brain tumour, which is what I specialise in doing, and a 5 per cent chance you'll die”, and then the patient dies because of the operation and the family will be very cross. They'll say: “You said there's a 95 per cent chance of success.” I say: “Yes, but I said there was a 5 per cent chance of disaster.” The same with the weather forecast. They're never wrong because there's always a probability. But from a patient's point of view, as patients, and I've been a patient myself, and my own son had a brain tumour, we want certainty. We want to know what will happen to me. Not a 95 per cent this or a 5 per cent that. So there’s a huge difference between the doctor’s perspective and the patient's perspective.
SS:We can actually swap roles in a little bit. Before we do that, I know that you specialise in brain surgery with local anaesthesia.
HM: Yes.
SS: Basically, the patient isn't sleeping when you’re operating on him.
HM: Yes, that's right.
SS: What is the reasoning behind it?
HM: Because - it only applies for certain sorts of tumour - tumours which are actually part of the brain, in the brain itself, consisting in effect of brain tissue, not of nerve tissue, with the cells called glial cells that surround and support and kind of look after the nerve cells. And the tumour looks very much like the brain and feels like the brain. It doesn't come with little dotted black lines and a pair of scissors saying: “cut here, don’t cut there”. And if the tumour is in a very important part of the brain, for instance, here in the speech area - most of us have speech here or movement here, - just looking at the brain with the patient anesthetised doesn't tell you where to stop, because the edge of the tumour looks like the edge of the brain. If the patient's awake you can ask the patient to do things, you can ask the patient to talk. You can use electrical stimulation to work out roughly where you are.
SS: So have you ever seen a significant change in a person's brain as you operate “live”, so per se?
HM: Yes, occasionally. Well, the most common reason is that somebody has an epileptic fit while you're operating and then they can become unconscious or paralysed or stop talking - things like that. If there's a problem with the operation, and you actually start damaging important brain, the patient will start to lose the function of that part of the brain, so occasionally I've had patients who started to lose the ability to talk or become paralysed down the opposite side of the body. It's a real risk, it happens. Not very often, but it happens.
SS:What makes operating brain much more difficult and sensitive than operating something like heart or spinal cord?
HM: Two things. First of all, the brain does not heal in the way bone and muscle and skin heals. Every time you cut the brain you damage it, and it won't recover. And secondly, the brain is incredibly delicate. You can damage some parts of the brain, you can kill the patient just by damaging one or two millimetres of brain tissue. Other parts of the brain can sustain quite a lot of damage - in particular, at the front on the right - without the person seeming to suffer any harm. But it’s very vulnerable, it's very delicate, it has the consistency of thick cream cheese. The main surgical instrument is a sucker - the miniature vacuum cleaner. Brain surgery is horribly crude actually. People think it's all terribly... It is high tech, but the actual reality is actually quite crude compared to the incredible complexity of the brain.
SS:You do have to cut the skull, right?
HM: That's easy. That's all right. That’s a simple bit. That you can do with the patient awake. If you put local anaesthetic in the skin, the problems will start once you open the membrane that covers the brain, the meninges - and that's where the trouble starts, that's where it becomes very dangerous.
SS:But I suppose like if someone has been doing this over and over again for years and years, and it is a job like anything else, and you've said it yourself, it's not the process….
HM:It's not a job like anything else, because you're dealing in people's lives. And if you make mistakes, the consequences are terrible. Now, sure, some surgeons and some doctors become very detached from their patients. And it depends on the culture you work in. I've worked in countries all over the world, and in some countries, the surgeons really seem to have minimal human emotional contact with their patients.
SS: What's better: to be emotionally involved or to be detached?
HM: “It's a question of balance” is the answer. It's a question of what patients expect. In countries like Sudan and Nepal and to a certain extent Ukraine, all of which I know well, the patients and certainly the patients’ families often do not want to know the truth, and they really don't want to be told how bad the disease is. On the whole and in England and in America, on the whole, patients and their families want to know the truth more or less. But even then with diseases like cancer, if it’s a cancer we can't cure, to get the balance right between giving the patient hope and being realistic is very difficult - and to get that balance right - and you often fail - you have to have some emotional rapport with the patients. If you are a completely cold detached technician you will not handle these problems well.
SS:But what about the process itself? I mean, if you had someone in your life that you really love who needed to get brain surgery, would you rather do it yourself?
HM: No, you can’t, you couldn't, you’re far too in it. My son had a brain tumour.
SS: So that's what I am asking. So, you would ask a trusted colleague?
HM: I wasn’t, I was doing general surgery and training at the time. He was only three months old. And some people say: “Did you operate yourself?” And I say, no way! You couldn't! Because all your mechanisms of self-preservation and detachment... you'd be simply too anxious. I once operated on a close personal friend, on my daughter's godmother with a malignant brain tumour. So, I knew she was going to die, and the operation was simply what's called a biopsy to confirm the diagnosis. And a very-very simple operation. So a bit reluctantly I agreed to do it because the family were very keen I should do it because we were close friends. And even that I found almost impossible, because I was so anxious, because I was not detached.
SS: What's the hardest decision you had to make? Because I understand, brain surgery is a lot about decision-making.
HM: Yes. That’s a real problem. I had to make many difficult decisions. I think some of the ones... I have many regrets over 40 years of practice. I think some of the most difficult decisions were when I treated people too much. I should have stopped. I operated when there was no realistic hope, and all I did was add to the patients’ and the families’ suffering. I can think of quite a few patients where I did that. On the other hand, with surgeons who are cold and detached, they will do that, and it doesn't trouble them.
SS: So you've said that we will actually never know how the brain works…
HM: Well, I think it’s unlikely. I mean the whole point about the future is that it’s unpredictable. So I think it's unlikely, we'll ever understand the brain in the way we can understand how a computer works or a clock works. And I think it’s unlikely. Somebody once said, you can't cut butter with a knife made of butter. I don’t know. But with the present technology we have of MRI brain scanning, electrode implantation in monkeys, and to a certain extent in human beings - it’s very limited to how much it will tell us. And we can't experiment on ourselves. We can't cut open our fellow humans’ brains and fiddle around with them, do experiments on them. We can to a certain extent on chimpanzees. I feel rather sorry for chimpanzees. Anyway, it's becoming increasingly difficult for ethical reasons. So there are major limits to what we can, to actual scientific research we can do on the brain.
SS: So following that logic you never really actually know what a patient's brain will do after the surgery and all we have to do is look?
HM: Well, you know to a certain extent, because we understand how various parts of the brain are more important for some [functions]. We know as the areas of speech and vision. Sure, they're all tied in together in complicated ways we don't understand. But with the operating, on the whole, you have a pretty good idea what you can get away with, so to speak, without damaging the patient, and when an operation is impossible.
SS: How closely are neuroscience and neurosurgery related, in the sense that do discoveries in neuroscience actually make advances in neurosurgery?
HM: Not very, except in what's called functional neurosurgery where you put electrodes into the brain for conditions like Parkinson's disease and things like that. There and again under epilepsy surgery, because there was quite where neuroscience is involved, you can take electrical recording of some single brain cells in terms of planning what to do. But in terms of the everyday problems like operating on patients who’ve haemorrhages, head injuries, things like that - pure neuroscience is a completely different [area], is a world away from the everyday world of the neurosurgeon.
SS:So you don't think of a human brain like neuroscientists think of a huge computer?
HM: No, on the whole not. I mean, as a surgeon I'm more like a plumber. I mean, the relationship between neurosurgeons and neuroscientists is rather like the relationship between plumbers and physicists who deal with the quantum mechanical properties of metals - there is a big gap.
SS:So when you're operating on brains you can remove something, right? You can remove the ability to talk, or to see, or to hear. Can you add something to a personality?
HM: No, there's been sort of fashions for implantation mainly using foetal brain cells from foetuses’ stem cells, but none of it's really worked yet. In terms of electronic implants - not really. I mean, there are various computer-brain interfaces, where you put electrodes on the brain, and this is being used on people who are completely paralysed. And then some of them then by thinking can actually move a robotic arm.
SS: I’ve read these crazy surgical records where it said that the human brain can be cut in half...
HM: It’s partially cut in half.
SS: They have a name for that…
HM: Callosotomy.
SS: Exactly.
HM: Split-brain. Yes, it’s a famous research done in the 1980s by Gazzaniga and Sperry. For certain sorts of epilepsy, dividing part of the brain in the middle, the two cerebral hemispheres, and they are two halves of the brain up here, which then join together. It’s like a trunk of a tree. The brainstem is the trunk. You can’t touch that. If you touch that, people die or are left terribly disabled. But then the trunk splits into two main hemispheres like that, and they’re joined by something called the corpus callosum which is billions of nerve fibres connecting the top of the right side of the brain to top of the left side of the brain. And if you cut part of that, it can help certain sorts of epilepsy in particular form of epilepsy where people just fall on the ground, called a drop attack. These people appear normal. If you met them you wouldn't know part of their brain had been cut in half. But you can carry out experiments on them where there's a sort of barrier which divides what they're seeing - the visual field - so the right side of the brain can only see things on the left, and the left side of the brain can only see things on the right.
SS: And supposedly they also suffer from split personality in some cases?
HM: Well, they do in the sense, yes. I mean sort of… But with this special experimental set-up. It's as though they're two separate people in there — to a certain extent.
SS: And you can’t sew it up, back again?
HM: No, you can’t. But the story is told of one man who had a split-brain operation and lost his temper with his wife and wanted to hit her with his left hand which was controlled by the right hemisphere, and then his right hand pulled it back. It may not be true but it's an illustration of the way you end up with this sort of split personality.
SS: So, let's just roll forward. I know you don't like this whole science fiction but we're not there yet. I'm talking about something else. Let's say we do have this crazy technology to achieve it, where two people, let's say you and I, we want to swap one hemisphere with another. Is it possible?
HM: No.
SS: No way?
HM: No way.
SS: Okay.
HM: There are eighty-five billion nerve cells in the human brain. If you took one cubic millimetre of the cerebral cortex - the surface of the brain - that can contain up to 100 000 nerve cells and 1 billion electrical connections. That is seriously complicated.
SS: Complicated, but theoretically?
HM: Theoretically. I don't believe in the human soul. I believe everything you and I are thinking and feeling at the moment is generated by the activity of our brains. But we really don't know how. I mean, yes, we understand a certain amount about vision and movement, but how consciousness arises, how pain arises - we haven't a clue. And there's no way… It happens. For most people like myself with enough knowledge of the brain, thought and feeling are physical phenomena, but the fact of the matter is that contemporary science even at the level of quantum mechanics cannot explain it. Which means we're very ignorant, there's a huge gap in our scientific understanding of the world.
SS: Maybe by the time we understand (if we ever understand) that's where the evolution of the human race ends probably, too. That's why we don't know much about it. You told me you don't watch much TV so I don't assume you've watched this series “Altered Carbon”.
HM: No, haven’t watched.
SS: Okay. It's pretty much about how you can take one person's brain and transplant it into another.
HM:That’s a science-fiction.
SS: Like Sheckley. I'm sure you read him.
HM: It's science-fiction.
SS: It’s nonsense?
HM: It’s funny.
SS: There's no way we can ever achieve something like that?
HM: Not in the foreseeable future. Likewise, the idea that some people have, that we can download our brains on the computer.
SS: That's what Elon Musk is saying so that you can enhance human brain with the chips. Is that science-fiction?
HM: That’s fairy-tales.
SS: Seriously? Because they're saying they’re already experimenting on it.
HM: Yes, sure, that's fairy-tales. I'm not saying it's impossible but with our present level of neuroscience and technology, there's no way we can do it.
SS:So this whole new fashion of maybe becoming immortal...
HM: Transhumanists, yes. It's fairy-tales. It's the old fear of death written in another form. Giving people who've lost, who have a deep fear of death... We have the need to feel we’ll live forever which until the modern age took the form of religious belief in an afterlife; the need for that belief is still there, but now some people dress it up in pseudo-scientific terms.
SS:All I'm saying is that when we see in today's medicine, how people are being robotised for needs like you can replace an organ, an artificial organ, so then you're asking yourself maybe someday...
HM: In theory, it is possible. I won't say it's impossible. But 85 billion nerve cells, trillions of connections between them - it’s quite difficult.
SS:So all of that like “put this cyber port in your brain” - that's like not happening ever?
HM: That’s science fiction.
SS: So tell me something: we do understand how memory is stored in a brain, don’t we?
HM: Not, really no. Very little.
SS: So there's no way we can remove what we don't want from the brain?
HM: No. I mean we understand some sort… with a limited understanding. Put it this way: we know which bits of the brain, if they get damaged, where we lose the ability to make new short-term memories in particular parts of the brain called the hippocampus and the fornices that are so-called experiments of nature: you see people who've had damage either from a head injury or from an operation. They can't make short-term memories. Long-term memories which is what eventually we lose with Alzheimer’s disease and dementia seem to be more to do with the brain as a whole rather than any individual points. But nobody can locate a memory in the brain. Having said that, we know that maps are located in the hippocampus. As a famous study done on London taxi drivers, you may have heard of an MRI scanning which had London taxi drivers, you’d have to pass this examination called “The Knowledge”. They have to know the entire road map of London and not just the layout but which are one-way roads, which is the quickest way of getting it from Belsize Park to Brompton Road or something. It takes years to learn, and the hippocampi in these London taxi drivers, the ones who passed the test are bigger than the ones of people who failed the test. Likewise, you know that professional pianists have bigger hand areas in the movement area of the brain than in non-professional pianists’.
SS: So I don't know if you've operated any real-time geniuses but would their brain be any different from?...
HM: No. Not what you can see. I mean, it’s like all these ideas of, you know, Lenin's brain was kept, and Einstein's brain was cut into slices. This is a very simplistic way. Sure. But by definition, every brain is different because we're all different. We are our brains. Every time we think a thought, that is a physical process in our brains. So an awful lot of current neuroscience and particularly cognitive neuroscience which is what psychologists now call themselves is really just saying, “Well, yes, when we think certain thoughts, certain parts of the brain are more active”. That doesn't actually at the end of the day explain anything because we know already that everything we think and feel is a physical process in our brains.
SS:So, you are a man of science, I don't suppose you believe in anything like the afterlife or…
HM: No. So we'll put it this way. I think it's unlikely. You can't prove it or disprove it, but it seems unlikely to me. And why as a neurosurgeon it seems unlikely, because I see and have seen many-many people who suffered damage to the front part of their brain, which is where our social behaviour and moral behaviour seems to be organised, because people have suffered particular head injuries, they've suffered damage to the front of the brain, they suffer personality change, they suffer personality change in terms of their behaviour towards other people. It was also almost always for the worse: they've become cruder, vulgar, swear, coarse, disinhibited.
SS: And you can't reverse it anyway.
HM: And if what we think makes us particularly human can be altered by physical damage to our brain, well, when our brains die, I reckon, we die.
SS: Not necessarily. I mean the moral part is more like the religious part, but I'm just saying it can be anything. But would that mean that those billions, and billions, and billions of nerves that are connected to each other and their existence the minute person's heart stops to beat?
HM: Well. There's a rather alarming work done recently in America looking at dead pigs’ brains when they went to an abattoir. They took some brains out of pigs that have been killed a few hours earlier and showed that some of the brain cells are still alive. They'll die in time and what it means goodness knows. Likewise, you know some patients in what's called persistent vegetative state just lie there without moving, have been tube-fed. You know, they’re only alive because of medical treatment. Some of them, it seems, have some kind of activity in their brains. Then we don't know what it means. It’s all very strange.
SS:So, it is very strange but still thanks a lot for shedding at least some light on this strange world of neurosurgery.
HM: Casting light is to say it's even more… As of all science. You open the door, and then you find a lot of new doors on the other side. Religion it's the other way round, it's a closed door and there all the questions are answered. With science you ask a question - you have an answer and then a lot of new questions appear. That's what's so interesting.
SS:I suppose that's how life works in general.
HM:Well, yes. But as we get older it kind of runs down a bit.
SS: Anyway, thank you so much for a wonderful chat. It's been a pleasure talking to you. Good luck in everything.
HM: Thank you very much.