Instant Genius - How our brains create our sense of self

Episode Date: February 3, 2025

Over the last century or so neuroscientists around the world have been uncovering more and more about how our very identities are formed by the different cognitive functions carried out by our brains. And we now know that our identities can even be transformed by brain disorders such as stroke, dementia of head injuries. In this episode, we catch up with neurologist Masud Husain to talk about his latest book – Our Brains, Our Selves, What a Neurologist’s Patients Taught Him about the Brain. He takes us through some of the discoveries he has made while treating patients during his long career. We learn how a stroke led to a previously successful, motivated man to suddenly lose interest in all areas of this life, how a previously demure, shy woman began dressing flamboyantly and insulting people in the street thanks to the effects of dementia and a woman suffering from Alzheimer’s began to think that there were multiple copies of her husband. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton, for the stay. This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name audio alongside French acoustic specialist focal combine handcrafted tradition with cutting-edge innovation and high-end materials delivering digital precision with analog warmth so you can experience exceptional sound at home music just as the artist intended visit name audio.com to learn more hello and welcome to instant genius a bite-sized masterclass in podcast form every monday and

Friday, you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor at BBC Science Focus. Over the last century or so, neuroscientists around the world have been uncovering more and more about how our very identities are formed by the different cognitive functions carried out by our brains. And we now know that our identities can even be transformed by brain disorders, such as stroke, dementia or head injuries. In this episode we catch up with neurologist Massoud Hussain to talk about his latest book, Our Brains Ourselves,

What a neurologist's patients taught him about the brain. He takes us through some of the discoveries he's made while treating patients during his long career. We learn how a stroke led to a previously successful, motivated man to suddenly lose interest in all areas of his life, how a previously demure, shy woman began dressing flamboyantly and insulting people in the street thanks to the effects of dementia. And also about a woman suffering from Alzheimer's, who began to think there were multiple copies of her husband.

So today we're talking about your book, Our Brains, Ourselves, What a neurologist's patients taught him about the brain. So first off, what's the premise of the book? The real premise is how modern neuroscience is helping us to understand how our brains create our identities, ourselves. That's really the core of the book. And through the stories of seven very remarkable people, patients who came to see me, we get to discover how our identities are the result of different brain functions, how ourselves are an emergent property of different cognitive functions in the brain. So before we get into that, just so we're all on the same page, you know, what exactly does a neurologist do?

You know, what's your day to day? Yes, so I'm a clinical neurologist and an academic neuroscientist. So in my neurology job, I see patients who come to see me with concerns about their memory or the forgetfulness about words or possibly that they might be seeing things that they don't think are real, that they're having difficulties in paying attention to information, or they're, they're not as good as planning as they used to be. Those are the kinds of things I see because I'm a cognitive neurologist. I see people who have those kind of concerns. As neurologists, we're all trained also across the board in brain and nerve disorders that could be peripheral nerve or in the central nervous

system. But I should also mention that I'm also a neuroscientist, so actually a lot of my time is spent on the science underlying brain disorders in healthy people. And I'm particularly interested in looking at the brain at the systems level, not at the molecular level or the cellular level or the genetic level, but how networks of brain regions create brain functions. Great. So let's have a look at some of these sort of case studies that you detail in the book then. So you start off things with a man in his 30s who suffered from a stroke. And this seemed to hugely affect his motivation. So can you tell us about that?

I mean, it's a startling case. He was in his 30s, and he'd been a very productive, highly gregarious, very social individual, really the life and soul of the party, and enormously appreciated by his employers because he was really good at what he did. But unfortunately, he had not one stroke. It was two tiny strokes, which is unusual. and they affected these deep nuclei in the brain called the basal ganglia. And most of the interest in the basal ganglia

has been in how they're involved in producing action, movement. But in this case, this guy recovered very quickly from his strokes. He was really moving around within a few days. But when he went back to work, he clearly didn't seem to be interested in what he was doing. He'd become profoundly apathetic. losing motivation to do anything. And at first, his employers, also his doctor,

just thought it's a natural reaction to having a stroke. You're depressed. You're not feeling well. His GP tried him on antidepressants. He didn't get any better. And eventually, his employers had to fire him because he just wasn't really doing anything. But his level of apathy was so profound

that he couldn't even be bothered to get unemployment benefit. So he couldn't pay the rent. Some of his friends said, why don't you come and stay with us? And very soon regretted that because he barely did a thing. You know, he wasn't helping them out with the house. He wasn't helping him out in any way. All he did all day long was just sit there waiting for them to come home, cook dinner for him.

He contributed nothing to the household. And slowly they became very frustrated. So this man had had a huge change in his personal identity. wasn't really the person he was before, a change in himself. But he also had a remarkable change in his social identity. He really wasn't connecting with those people who were around him. And his GP in frustration sent him to us because he didn't know what was going on. And what we found was that he wasn't depressed.

He wasn't hopeless. He wasn't sad. He was actually positive about the future in many ways. But he just could not be bothered to make the effort to do it. anything. So when I'd ask him, what would you normally do if you were on your own? He said, I would listen to music. And why aren't you doing that now? Because it would take me time to put together my music system. How long would it take? Five minutes. So he couldn't put in the five minutes of effort to wire up his music system. And he was a remarkable case for us because it was so transformative

sudden change in a man who wasn't depressed. And what we unearthed by doing some brain scans, but also trying to look at the mechanisms underlying his apathy, was that he wasn't incentivised by anything. He didn't find anything rewarding, so he wasn't willing to put the effort in. And by finding that out, we thought about a treatment that might be helpful for him. So what was that treatment and what's the idea behind it? Well, we know from a lot of basic fundamental neuroscience in animals that actually there is a circuitry involved in motivation. You know, we take motivation for granted. There are some lazy people. There are some highly motivated people. We don't really think about the fact that there might be a brain basis for that variation.

But here was somebody who was startlingly motivated before his strokes and now he was completely apathetic. And it turns out that the two tiny strokes that this guy had had affected this motivation circuit in the brain. And what we know from fundamental neuroscience, animal studies, is that that circuitry depends a lot on the neurotransmitter, one of the neurochemicals in the brain, called dopamine. And many of your listeners will know that dopamine has been implicated in how the brain processes rewards. And so we thought that perhaps if we boosted that system, you would now find things rewarding. And to our surprise, by using a drug that really did target the dopamine system very specifically, after three months we found this guy who really wasn't looking after himself. It'd become very disheveled, wasn't doing it, anything at home, made no effort in any shape or form,

came back to see us, which was also remarkable, because we normally have to work very hard to get him to come and see us. Suited, he had a haircut, he got a job after all this time, and most remarkable, he had a girlfriend because, you know, he really wasn't meeting anyone before. This was really remarkable. And so it seemed that his motivation had been extinguished by these strokes, but it was possible to restore it,

given the neuroscience we knew. So that was a remarkable finding for us. I mean, this chap is extremely rare. There aren't many people in the world have these tiny little strokes strategically located in this circuit. But it turns out that there are lots of brain conditions which are associated with apathy,

lots of, for example, neurodegenerative conditions like Alzheimer's disease or Parkinson's disease. And what we found is that although the pathologies, the molecular reasons for having Parkinson's disease is very different from the molecular reasons for having Alzheimer's or a stroke, if the circuit that's affected by that pathology is the same circuit that was affected in this guy with the tiny strokes, you can also get apathy. And so we now know that a third of people with Alzheimer's disease

have apathy, very similar numbers with Parkinson's disease have apathy. So it's telling us something about how we could try and restore motivation in those individuals who are far more common than this rare person we saw. So let's have a look at another sort of personality change study that you mentioned. This is also super fascinating. It's the lady that was previously very sort of demure and meek. Then all of a sudden she started dressing flamboyantly, spending money outrageously, and essentially just insulting people in the street. Yeah. So what was going on there? Well, she turned out to have a disorder which affected her frontal lobes. It's a disorder we call fronter temporal dementia. It's very different from Alzheimer's disease. Often these patients at the beginning of their illness have intact memories. But what changes is what we might call their personality and they become disinhibited. The things that we normally stop ourselves from saying she might say out in the street, you know, she saw a woman. who was in a tight dress and said, that's not doing you any favours. You need to lose weight,

love. And, you know, her insight into this was that she'd lived all her life, not saying things the way she felt, she just felt like she should be able to save them. But what it gives you insight into is how the frontal lobes, which are, you know, hugely developed in humans, they're involved in lots of processes, for example, planning, thinking ahead strategically. But they're also involved in fundamental, simple things like stopping yourself from blurting out what you think. We've developed those frontal lobes as we grow older through childhood, because, you know, you can see it. Children, they'll blurt out what they're thinking sometimes. But as they grow, as the teenage brain also grows, there are these inhibitory mechanisms which suggest that

in this social setting, it would not be appropriate to do that. Now, of course, in other social settings or cultures, there are a whole different set of rules, how to behave. But in the culture that we live in, that isn't acceptable. So she said, you know, she didn't care. She was going to say what she felt. And she didn't care that she was spending money on seven bikes when she didn't need them. She felt like it. So she was going to do it.

And unfortunately, she had this illness, which we call front of temporal dementia, which really is a very corrosive illness. in the sense that personal identities change, but it really impacts on the way that families interact with people they've loved for many years. They become very, very difficult to engage with. So also in this case, you were able to develop a treatment. So what was the idea behind that? So in this case, it was more serendipitous, because what researchers had stumbled on is that a drug,

which was originally developed as an antidepressant, which affects the serotonin system. It's not the same as normal SSRIs, the things like Prozac, but this drug does have an impact in reducing this sort of disinhibited behavior, and it turned out to be highly successful in her, at least initially.

But these aren't cures, this is a symptomatic treatment. So obviously this is a very extreme example of this sort of thing, but does it exist on a spectrum? you know, people will just be slightly disinhibited. Yeah, I mean, this is a really interesting question because there are people who present to us, often later in life, having been very well,

who somehow seem transformed, their families are worried about them, we investigate them and we can't really find anything. Very occasionally we find a genetic mutation which can be associated with front of temperate dementia, but it's not as if we can see, anything on their scans, you know, it's not as if their frontal lobes have shrunk, but nevertheless, they're showing disinhibited behavior. So in that case, we think potentially that's a sort of, you know,

subclinical form in the sense that we can't see the full-blown syndrome. But there are lots of people we know who vary in their levels of disinhibition, and it doesn't have to be front of temporal dementia. You know, there are other conditions, even developmental conditions, where people can seem to be disinhibited. Some of those conditions might have a label. Some people might say, oh, well, they also have features, let's say, of attention, hyperactivity disorder, ADHD. But there are other people who don't have a label, but clearly are on a spectrum. And the really intriguing question for us is whether we can find the biological basis for variations in control, inhibition, or even motivation, like we were talking about the first guy,

that explains how different people seem to be highly motivated or not. And of course, that can change. As a teenager, you might be someone who isn't very motivated and you might be someone who's disinhibited. But your brain changes over time. And to understand how the brain develops also gives us insights into how things go wrong later in life. So that's sort of coming back to what you said earlier.

Like by studying these extreme cases, we can sort of extrapolate back and develop treatments of people who are suffering from something, but not quite in the same sort of extreme way. That would be the ideal, but I think what we appreciate is that human brains are incredibly difficult to understand. So we've learned a lot in neuroscience, but it's still a young science, especially when it comes to human brains. So we might know the fundamentals about how the nerve cells, the neurons communicate.

We might understand something about the nerve cells, the neurons communicate. we might understand something about the networks of nerve cells or their connections, how they might learn. And that's a mean very important, for example, in artificial intelligence models. Developing those models has come a long way from actually understanding how brains might work. But we are so, so ignorant in so many ways about how human brains really operate. We're at a very kind of superficial level. But nevertheless, it's really exciting to be in this area because there's so much

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So there's one really interesting study that you mentioned with a man who's very articulate, very well-spoken, very knowledgeable, but all of a sudden he started to forget the meaning of words. So what do we know about that? When he first came to see us, in conversation, there was hardly anything you could detect that was wrong with him. And he was worried that he was having difficulty finding the right word in conversation. But we stumbled upon the fact that there was a problem because he used to play rugby. When I asked him which position he played in, he didn't really understand the meaning of

that word position. So I tried to clarify and said, well, were you in the scrum? And he didn't really understand what the scrum meant. Now, clearly, if you've played rugby, even if you haven't, you have some idea of what the scrum is. So that started telling us that maybe there is something wrong with this person. And as we dug deeper and deeper, we found what he had wasn't just, he hadn't forgotten words. He'd forgotten what the words mean. So, you know, words for us are a label, a simple way of encapsulating concepts.

Like the word dog encapsulates a whole bunch of things about what dogs might be like. They bark. They have tails. They're domestic pets. So we can classify dogs in one way. But if, for example, I'd asked him to tell me about different types of dogs. He really was stuck. He could tell me something about dogs,

but he couldn't really tell me about Labradors or collies or Alsatians or poodles. or poodles, you know, he didn't really understand the differentiation. So he had a general concept, but he didn't have any granularity to that understanding of concepts. And as we looked further and further, we found that his real problem was his semantic memory. So that's really the memory about concepts. So it's not like what we call episodic memory, memory of things that have happened in your past. He was actually quite good about recollecting things that had happened to him. He just didn't understand words and the concepts they were linked to. And when we performed an MRI scan of his brain, we found that he had shrinkage of one part of the left

hemisphere of the brain, the left temporal pole, which we now think is really important as a sort of hub for collecting information that relates to a concept like dog or bird or furniture or computer. all those kinds of things. And these, we've been talking about objects, but they're also about other concepts, you know, like love or politics. All these things are brought together in a sort of conceptual store

in that left temporal lobe, and this patient's store was slowly being degraded away. So it wasn't just the fact that he couldn't remember the words, he couldn't link them to the concepts. Yeah, so obviously that must be a horrible experience, just unto itself. But one interesting thing that you talked about was previously his sense of humour was very sharp and he was kind of known for that. But this affected his ability, his sense of humor

and his wit, which seemed to in turn really affect his wife. Yeah, I mean, if you think about humour, it's a really sophisticated system because it depends on turning things on its head often. So Victor Raskin, who has studied humour in great detail, came to an important conclusion, is that to really understand a joke, there has to be something where the meaning of a word is turned on its head in some way, that that's how the punchlines of jokes works. You have to know something beyond the simple, superficial meaning of a particular word to get it. And that obviously requires you to have grown in a culture in some way. So, for example, irony, which is often present in English humor, you wouldn't get irony if you were just someone who was learning English for the first time, because you have to be embedded in that culture to get the fine nuances of how a word is being used in a particular circumstance.

So this guy who is losing his idea of concepts, semantics, meanings, now found it hard to understand jokes, but he was also someone who was very humor. and he was losing also his ability to make people laugh and enjoy him in the way that they had. So what do we know about what was causing the shrinkage in this area of his brain? Right. So what we've learnt a lot about is that many neurodegenerative conditions, his was something we call semantic dementia, but also other conditions like Alzheimer's disease or Parkinson's disease, involve atrophy, shrinkage of selective parts of the brain, different for different conditions. And if you look under the microscope, what you find is that there are different proteins

which have been deposited in these conditions. So it's a bit like finding different things being deposited in the dustbins outside a home. So one kind of condition is associated with one kind of stuff in the dustbin. one kind of protein. So Alzheimer's disease is associated with amyloid and tau, for example. In this condition, semantic dementia, there's often something we call TDP 43. It's another kind of protein in the dustbin. So something's happening in the house, the neurons, which is leading to this stuff being deposited outside in the dustbins. And there are different protein aggregation syndromes which seem to be associated with different neuropathologies.

And that's important also for designing treatments because people have thought, well, what would happen if we could get rid of these protein aggregates? What would happen if we could get the binmen to come along and take away the rubbish that's being accumulating outside the house, outside the neurons? And that's exactly the way that people have developed antibodies specifically for these proteins to try and bind to them.

and mop them up and take them out of the brain. And until very recently, that has not been very successful in changing brain function. So the antibodies have been designed. It's quite clear that you can amazingly take out these proteins which have been deposited, like the dustbin men coming and taking away the rubbish. But it didn't make much difference to brain function.

It's only in the last few years that two drugs have been licensed. both in the United States and more recently in the United Kingdom for Alzheimer's disease treatment which work on this principle. In the UK, although it's been licensed, it's not been approved by nice because up to now it's not been thought to be cost effective and it makes a very small difference but nevertheless it's a proof of principle that it might be possible at least in some people early on in the disease. If you clear the proteins of rubbish, you might have an impact on the neuronal function. So earlier on then, you mentioned something called episodic memory.

So there's a case study in the book that deals with this, which is, again, absolutely fascinating. If a woman who didn't recognize her own husband and at times even thought there were multiple sort of copies of him. Yeah. So what do we know about that? It's a rare phenomenon. She actually turned out to have Alzheimer's disease, and it's quite a rare phenomenon.

in Alzheimer's disease. I mean, the story is absolutely remarkable in itself because it was told to me by her husband who said that it'd gone away with her for a little break in Cornwall and they'd had a great time and they were just about packing the car, ready to go home and she said, oh, you can't come home with me. And he said, what do you mean? And she said, well, my husband wouldn't really like it. if you came home with me, you know, he doesn't know about us. He found that completely shocking, as all of us would. And he managed to persuade her to say, look, look, I know your husband really well. Why don't you phone him and he'll be okay with me coming?

So eventually she did phone and while she was phoning he slipped out to take the call on his mobile phone and said it would be fine. But she had clearly thought that this person, this body, actually was occupied by somebody else, her lover, whereas actually it was the same body as her husband. And this is sometimes called a sort of misidentification delusional syndrome. It can occur in other diseases. But it's quite interesting.

Right at the beginning we were talking about how the brain creates ourselves and identities, but it also allows us to think about other people. It doesn't mean much, if I'm thinking about myself, unless I compare myself to other people and knowing who other people are. And in this case, although she was seeing somebody who she'd seen for years and years and years,

she thought the self that occupied that body was a different self to the one that her husband was. And sometimes, you know, even now, when she's at home, she'll say, I wish she'd sort yourselves out who's going to sleep? with me tonight. So it's that level. It wasn't simply just misrecognition. It was misunderstanding

who the person was that occupied this body. So what do we know about what was going on inside this person's brain? Yeah. So it makes you think fundamentally about how you do this. So of course, at a basic level, you have to have facial recognition processes. Actually, that wasn't bad in her. She could recognize different kinds of people, but occasionally did stumble on this. But you have to go a little bit further. It's not just face recognition. There's a whole series of things that are associated with the face. Who are they? What's your relationship to you? Do you like them? Are they people who you find offensive? Would you like to go out with them? All these attributes of them are attached to the face, just like we were talking

about a word is attached to a concept. A face is attached to a concept and a conceptual history. So somehow, for her, there had been a degradation of the linkage between the physical persona. She recognised that he was someone close to her and the history behind that face. So we've covered quite a lot there. As you mentioned earlier, neuroscience is a very sort of young field. So looking into the future, are you optimistic about the discoveries that we can make? I'm really optimistic, yeah, because... although there are profound obstacles about getting inside an organ which is covered by a hard skull,

we have made so many strides even in the last 30 years since I've been practicing neurologist and neuroscientist. 30 years ago, if you went to most neurology centres, you'd be lucky to find one neurologist interested in dementia because it was felt that nothing could be done. Now you'll find that there are tens of neurologists who are interested in these conditions. Now, we may not be able to make much of a difference at the moment, but we can make a small difference. And even if by changing the symptoms which are difficult for other people to deal with or even the patient to deal with, we improve the quality of life of patients and their families, that's a win for me. But as I said, we're now getting to the point where we're thinking about and enacting ways in which we

can try and perhaps turn back the effects of neurodegeneration, for example, by trying to mop up these proteins that are deposited. That may not be the final solution. It is unlikely to be. But just as in cancer, what happened was a collection of drugs, a cocktail of drugs, first started to show real improvements. We're on that route here. Just as in heart disease, initially the strides were very small. A little aspirin might reduce your risks by so much. Well, we have to start somewhere and we've started that process in human brain disorders. And as for fundamental neuroscience, I mean, we've made huge, huge strides in that area. But it has required the appropriate level funding and interest from the public to lobby

politicians to spend on these kinds of diseases. Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC Science Focus. That was neurologist Massoud Hussain. To discover more about the topics we've just discussed, check out his latest book, Our Brains Ourselves, What a neurologist's patients taught him about the brain. If you liked what you just heard, then please do consider subscribing to Instant Genius on your preferred podcast platform. The current issue of BBC Science Facus magazine is out now. Pick up a copy wherever you buy your favourite magazines or downloaders on your app store of choice.

You can also find us on Apple News or online at sciencefocus.com. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name audio believes you can have digital precision with analog warmth. Alongside French acoustic specialist focal, name creates high-end audio systems, combining innovation with craftsmanship so you can listen to music, just as the artist intended. Discover more at name audio.com.