Exploring the Evolving Brain with Neuroscientist Joseph Jebelli

Episode Transcript

Dr. Correa:
From the American Academy of Neurology, I'm Dr. Daniel Correa.

Dr. Nath:
And I'm Dr. Audrey Nath.

Dr. Correa:
This is the Brain & Life podcast.
Welcome back. We're excited to start again with a mailbag question. Jason asked us, "Good morning, about one and a half years ago, I got a brain infection. I took antibiotics and the infection is gone, but there's still some scar tissue and it's causing some brain blur. Do you have a podcast or any information or anyone who has been through it?"

Dr. Nath:
Daniel, I think what Jason may be referring to is that he may have had encephalitis, which would be an infection or inflammation of the brain. And he mentioned taking antibiotics, it may have been because of a bacterial infection. And oftentimes when people have these types of infections, we can treat them and deal with bacteria and kill all of the stuff that shouldn't be there, but the brain is sensitive and sometimes can develop scar tissue wherever that infection was present. So he mentions that since then he has had brain blur and that could mean a number of different things. Possibly brain fog or word-finding difficulty or memory issues or difficulties with spatial perception, which depending on what part of the brain may have been affected, all of those are possible. So I'd say there are many people that go through this, Jason, who have overcome an infection but still have some residual injury in their brain and depending on where in the brain that can affect symptoms. And Daniel, I know in your time in the military you have seen many patients with many different brain lesions in different places.

Dr. Correa:
One of the things that happens and occurs to people over time as they get injured to the brain is sometimes they can have changes to their thinking. And then there's this whole question, do they have dementia? Or what is it it exactly that's causing changes with their mind?

Dr. Nath:
And sometimes repeated head injury can potentially predispose someone to an early dementia, as we talked about on a different episode.

Dr. Correa:
So Audrey, here's a total brain nerd check, even though we spend our time working with brains and seeing patients with people living through different neurologic conditions. Do you spend your extra time watching TV shows or listening to other podcasts about brains? I'm guessing yes because you're here with me.

Dr. Nath:
I mean, most recently Limitless With Chris Hemsworth on Disney Plus because I was preparing to speak with BJ Miller about that series. And it's all about different ways to look at the limitations of your mind or are there really limitations and what can we overcome and what can we not? So I do, I don't know, you probably do too, right?

Dr. Correa:
Yeah. I enjoy actually sometimes exploring how the brain and our minds get explained to all of us, even in some areas we're not experts in. And then also just understanding how it gets explained to everyone in pop culture. So on Netflix, I've watched some episodes of The Mind Explained and on that's on Apple TV, also The Brain. Very interesting ones. And so today's episode we feature a neuroscientist from the United Kingdom who has published popular books for people to help them understand more about the brain. He specializes as a cell biologist in Alzheimer's. In his most recent book, How the Mind Changed: A Human History of Our Evolving Brain, it's amazingly interesting and explores even the ideas of how both society and our brains have changed over time.

Dr. Nath:
Oh, that's interesting. This is something that I think about a lot and it comes up with our patients a lot, but I think in some ways our brain has not quite adapted to modern life and a lot of aspects of modern life. The screen time, the constant stress, I feel like we haven't really caught up to that. There's aspects of modern life that I think we're still not very good at, some of it may be because of how our brain has evolved.

Dr. Correa:
Joseph Jebelli is a UK neuroscientist, he also wrote another book that we get into a little bit that really touches how brain disorders and neurologic conditions like Alzheimer's have touched his life. His first book, In Pursuit of Memory: The Fight Against Alzheimer's, he interviews families from around the UK. So really amazing and touching how he explores all these concepts for all of us and then also shares his own perspective.

Dr. Nath:
And next week, please join us as I got the opportunity to speak with Cameron Boyce's parents, Victor and Libby Boyce about epilepsy and sudden unexpected death and epilepsy on February 9th.

Dr. Correa:
To have them open up and share the memory and celebrate Cameron Boyce's life. And the following week, in honor of Caregiver Awareness Day, we will feature Michelle Boyaner and her documentary, It's Not a Burden, highlighting the stories of families and care partners of people living with different adventures. Really impactful. Stay tuned.
Welcome back to The Brain & Life podcast. Today our guest is a UK neuroscientist specializing in the cell biology of Alzheimer's disease. Dr. Joseph Jebelli is also the author of a recent book called, How the Mind Changed: A Human History of Our Evolving Brain, where he explores how and why our society has advanced faster than our brains and what that means for all of us. Also, in his first book In Pursuit of Memory: The Fight Against Alzheimer's, he applies his perspective as a researcher in the field of Alzheimer's while staying in touch with the personal stories of the scientists who dedicated their lives to curing or working towards a cure for this horrible condition. And also importantly, the realities of the people living with Alzheimer's and their families. Dr. Joseph Jebelli, thank you for sharing your perspective with our listeners and joining us here on the Brain & Life podcast.

Dr. Joseph Jebelli:
Hi. Thank you for having me. It's really good to be with you.

Dr. Correa:
So Dr. Jebelli, tell us about what drew you to study the cell biology of Alzheimer's disease?

Dr. Joseph Jebelli:
I first became interested in Alzheimer's really as a child seeing my grandfather develop the disorder. And as I recount in my first book, I was a teenager at the time and I didn't really know what was happening to him, he was just very disorientated, very confused. And one of my most abiding memories is he would often sit at the dinner table and then get up and just walk off and he would get lost and my father would have to find him. And I was also thinking, what's wrong with granddad, essentially? And then it was only when I started studying biology and then more specifically cell biology started to become really fascinated by the brain and in particular by this disorder and many other disorders of the brain.
Because I just essentially wanted to know what was happening to my grandfather. And I'm endlessly fascinated by the brain, how this three pound mass, 85 million neurons comes together to produce everything that we are. In a strange way, witnessing the decline of my grandfather's cognitive stability brought that more to light, when you realize how powerful and amazing neurons are and the brain is, is when you see an individual who's losing those neurons and synapses and how that radically affects them in every way. So I suppose it was a combination of seeing my grandfather grow up but also just my love of the academic side of cell biology and neuroscience.

Dr. Correa:
Now I'd like to start with your first book, In Pursuit of Memory: The Fight Against Alzheimer's. As you started down this chase to understand Alzheimer's, can you describe or tell us a little bit more what we know about the basic science like you described about what is Alzheimer's?

Dr. Joseph Jebelli:
We know that it's a neurodegenerative disease that involves massive neuronal cell loss as well as the loss of synapses. And there's a debate about how much of those things contribute to the cognitive decline. Is it the neuronal death or is it the synaptic death or is it both? And alongside the neuropathology, so the neuronal death and the synaptic death, you see lots of cognitive symptoms, such as loss of navigation, terrible loss in memory, great deal of confusion, and just a general deterioration over time of thinking skills, thinking ability. In terms of the cause, that's one of the greatest mysteries and I spent my entire first book trying to hunt down the causes and good treatments and things like that. It's a great mystery, I mean, there are lots of different schools of thoughts. As I said, there are some people who think it's just the buildup of these plaques in the brain, these sticky proteins that build up in the spaces between neurons called amyloid plaques. And then there are others who say, "Well, actually no, it's the buildup of these sticky proteins within the neuron, which we call tau tangles."
The latest science tends to suggest that it's obviously both, that actually the plaques maybe trigger the tangles, but then maybe the tangles are more toxic to the neuron. But then there are other ideas as well that maybe it's an overactive immune system. A lot of the research I did was looking at the brain's immune cells, these things called microglia and how they respond in Alzheimer's and other neurodegenerative diseases. And all of that research has shown that you get this toxic level of neuroinflammation which actually makes the disease worse and may even be a driving component in the disease. Interestingly, it might not be essential to understand all of the molecular causes because it's such a widespread disease now that in many ways I think as much as we need to understand that, it's also crucial to stop it in its tracks. We need to find ways of basically preventing neurons from dying and preventing synapses from deteriorating. It's a great mystery and it's the defining plague of our time, I think.

Dr. Correa:
It's an amazing example how sometimes even a limited understanding about how a condition progresses and its process that happens whether in the brain or some other part of the body may be very limited, but we can still pursue science to help treat or manage or even hopefully in the future cure. Now in your book you also interviewed and shared stories of people living with Alzheimer's. Can you recall one of those stories that still impacts your understanding of the condition?

Dr. Joseph Jebelli:
I interviewed lots of patients for that book and there was one that I do think about very often is Carol Jennings. She's this incredibly brave, phenomenal, game-changing patient in the Alzheimer's field who realized that within her own family many people were getting Alzheimer's disease and it was so many, it just too much to be a coincidence, there must have been some genetic underpinning. And so she actually went to a group of scientists in London, this was years ago now, and she allowed them to take blood samples and to actually investigate what was going on in their family. And it was her coming forward that led to the discovery of the very first genetic mutations in the amyloid gene that underlies the plaques that we think cause the disease. And that led to, in her family, the type of Alzheimer's called early-onset Alzheimer's where people can get it in their fifties, forties and sometimes even in their thirties.
It was fascinating because once she found out that she had it, there was a point where she could find out if she possessed the gene that would give her Alzheimer's disease. And as soon as she found out that she had it, she spent her time campaigning to raise awareness for Alzheimer's research, just being a tireless champion of research. And without her and her family's efforts we would be arguably decades behind where we are now in terms of our understanding of the disease. So I think that story really stood out for me. But there are many other stories in the book about lots of other really brave Alzheimer's patients.

Dr. Correa:
Nice to hear that even in a situation where she couldn't necessarily receive a cure or treatment, that she still activated herself to be a supporter of the community and connect with the community. In that book, you also talked about some of the theories and ideas about prevention of Alzheimer's and you talked about the interesting history of ideas of delaying aging as far back as even Cicero discussing the theory of exercise delay or prevent impacts of aging. And more recent studies have shown increasingly the benefits of exercise on brain health. I'm wondering what other brain health and on disease prevention concepts that really stick to you, and maybe how are you applying some of these ideas in your own life?

Dr. Joseph Jebelli:
I suppose the thing I try and apply in my own life the most is exercise. Because when it comes to the prevention of Alzheimer's disease, it is often the common sense things that your doctor will tell you, eating a healthy diet, exercising, that do greatly reduce your risk of Alzheimer's. And exercise I think is a really important one because so many patients with Alzheimer's disease are also found to have some type of heart disease or something wrong with their hearts. Still don't quite know why that is. But when you exercise, it affects your global health. You would know this better than anyone. It's going to act as a shield against cognitive decline as well as a host of other things. And so exercise is a big thing. The Mediterranean diet as well, there's growing research to show that, that greatly helps with Alzheimer's disease.
I spent a while researching things like turmeric and the active ingredient in turmeric acumen because there's some studies showing that it can reduce your risk. But it's so difficult with things like this because as you know, proving cause and effect in any of these studies is quite difficult because you have to control for so many variables over a patient's life. But as I say in the book, the evidence for lifestyle interventions is growing, it's not diminishing and it does essentially come down to the common sense things.
But a thing that does stand out though is sleep. So I devoted a short chapter to sleep. Because we know now that when you sleep, the brain essentially cleans itself, it releases cerebral spinal fluid to essentially pump away lots of toxins that we think might contribute to disorders like Alzheimer's and aging and other things that could deteriorate your cognitive function. So a good night's sleep is obviously crucial. And there's lots of scientists now trying to figure out exactly what is about sleep that's helps clear away even beta amyloid in Alzheimer's patients. So there is definitely hope there. And it might be that understanding the lifestyle, environmental preventative factors might be an even better way forward because you're up against molecular genetics and 7 million years of brain evolution and so it's whatever we can do on our own lives to stand up to that is going to help basically.

Dr. Correa:
It's really the thing that so many of us are trying to focus and think about now. But let's take this back to Alzheimer's and neurodegenerative diseases and dementias and build on this idea of our partners and family. If our brains can adapt in our lifetime and maybe evolve with our society, how do you think the brains of caregivers who are there day-to-day with their family members for someone living with dementia could be affected and things that they should do to take care of themselves?

Dr. Joseph Jebelli:
It's really hard on caregivers. I say in my first book, "Alzheimer's is a disease that affects families." It affects whole families, not just the individual. Because for families, Alzheimer's is, as many say, it's the long goodbye, it's watching your loved ones slowly disappear over many years. And so that has a very debilitating effect on people, on carers and that obviously does affect their emotional wellbeing in a very serious way. And I suppose it's really difficult because it's something that many of the caregivers I spoke to were having a really difficult time and some of them just said, "I don't know how much longer I can keep going on doing this because it's just so heart wrenching to see my loved one deteriorating in the way that they are."
Many people with Alzheimer's, they don't have good caregivers or they don't have many family members and so I suppose the important thing is just to try and get as much help as possible. If you're a family member and you have other family members, then you should help that person with Alzheimer's by helping each other. Don't put it all on one person to provide the care, you spread the care out equally. It's difficult, but try and take time off. It's also important to understand that as a caregiver that the burden doesn't fall completely on you, your mental health is also important.

Dr. Correa:
In your recent book, you explore how society and culture has changed over time and the impacts on the brain's evolution. So can you describe for us what is known about past societies and culture and how their brain organized the world around them changed over time?

Dr. Joseph Jebelli:
With this book, it was another journey, in the sense a journey to understand why we have the brains that we do. How and why has evolution built the brains that we all have? So I essentially looked at the last 7 million years of human evolution and looked at all of the evidence about different brains in different early species of human over that time period. And we know that the earliest human had a tiny brain in comparison to ours. It was only about 350 cubic centimeters, which is about the size of a child's fist and ours are four times bigger. And so over that 7 million years, what we know is that the brain has gradually ballooned in size. So it went from 350 cubic centimeters to then 500 cubic centimeters, 1,000 cubic centimeters. And then in the last mere 500,000 years, which in evolutionary terms is really not that long, the brain essentially ballooned to a staggering 1,500 cubic centimeters, which the size of a cantaloupe melon in humans.
And I mean this is a really staggering, astonishing thing in evolution for something to balloon in size that quickly. And when you think about our brains in relation to other great apes and the things that we've achieved, sequencing the human genome, building the Large Hadron Collider, it's quite extraordinary how this has happened and how it's led to us being as sociable as we are. And so I suppose in each chapter I look at the different faculties of human beings and human brains, such as emotion, intelligence, sociability, memory, and try and understand where they came from and how they were expressed in our early ancestors, where in the brain we think these things came from and how they evolved over time. It took me on all these wonderful journeys and tangents into, as you say, early civilizations and early societies looking at hunter-gatherer tribes and early human ancestors and how our brain was forced to evolve and get smarter and smarter and smarter.
But all of the reasons for it are endless and endlessly fascinating, but it's a story basically about us and why we are the way that we are. And it's something that I don't think is really explored enough. We understand that we're evolved mutant apes essentially, but in terms of understanding exactly how we got to the stage where we are in terms of brain evolution is not as investigated as I think it should be. And so that was essentially my goal with the book to figure out why we have the brains that we do.

Dr. Correa:
You're talking about evolutionary science of pre-human ancestors. So even though you're saying early humans, you're not necessarily saying the Homo sapien brains, you're talking about other species that fall under the group or genus that we describe in evolution or in biology, the larger family that the species of Homo sapiens falls under and how the brains are different between them, right?

Dr. Joseph Jebelli:
Yeah, exactly. So with our genus, Homo, I explore the brains of all of the different species and you gave them earlier than that and you get to the earliest known human ancestor, Sahelanthropus tchadensis, otherwise known as Toumaï in the native tongue of where the fossils were discovered in Africa. So essentially I'm looking at different genuses of human, but going back 7 million years. So looking at Hominins overall I suppose as opposed to the other great apes such as gorillas or chimps, I'm basically going from the point that we diverged from chimps, near 7 million years ago to then just looking at the human line and all of the different genuses and species of humans.

Dr. Correa:
It's such an amazing idea to think of how the brain and the body has evolves over so many millions of years. But share for us, why do you think it's important for us to understand the history of our brain's evolution? What's the importance of that for us and for our society?

Dr. Joseph Jebelli:
I think it's really important to understand, to essentially remind us we are creatures like every other creature on this earth and we're stewards of nature, but we need to be reminded that we have an obligation to look after this planet, to look after the species, to not be as destructive as we have been. And it's difficult for people, I think, to think about that enough. And I understand why, because we've evolved such sophisticated brains, we're staggeringly intelligent, we've created these incredible societies, there are clearly massive differences between us and the other great apes. We've developed societies that are infinitely more sophisticated, you could argue, than theirs. Obviously it depends on how you define that, but that's another discussion. And I think because of that, we get distracted with our earthly distractions and we find it sometimes difficult to fully grasp that we're a species like any other and we're an ape like many others.
And so I think it's not just enough just to tell people, "You're an evolved ape." Overall our species is quite destructive to the planet, there are things that we need to think about more. It's not really enough, if you help people understand exactly how and why they are the way they are, exactly what the journey was that got them to this place, this mind and this body that they're inhabiting. I think then it helps people actually ground themselves more in a true scientific and biological understanding of human life. And there's lots of books about evolution in general, but there's not really that many about how the human brain evolved, so I wanted to help plug that gap as well, I suppose.

Dr. Correa:
And I'd like to then build on that and talk about the idea of betterment of our mind and brain for ourselves and for our society. One key perspective I was left from your book was the hope that we have the power to change our minds for the better and one way of doing that is through our societal and cultural evolution. Can you share with us more about how this and how our society can interact with our own biologic evolution?

Dr. Joseph Jebelli:
There are lots of really fascinating areas of evolution that people study, but one of the most interesting is this whole idea of cultural evolution and how it relates to biological evolution. And when we talk about cultural evolution, we're essentially talking about the things in our society that help us think in a different way or think better, help improve the fitness of our species overall. You can think about things like women's rights, for instance. That's a cultural phenomenon that's occurred relatively recently, but a myriad of studies will show you that when you have better gender equality, it boosts a nation's economy. And by boosting a nation's economy, you are a fitter group overall because you don't have to worry so much about predation or food or a whole host of other things. So that's one example of a good cultural evolutionary mechanism helping the fitness of the human brain and humans overall.
And I use other examples in the book, the idea of freedom over tyranny. It's no coincidence that we see people from these tyrannical regimes in the world migrating to places that are much freer and it's not just because they're living under tyranny, but it's a culturally evolved mechanism that will help the fitness of their group. And so scientists have lots of ways of measuring this, there's the idea that once a group picks up a behavioral trait or a cultural trait and it keeps on mimicking that, other groups will also then start copying that behavior and then it builds up over time to then affect the fitness of the group overall. And we can keep this going with just having great education systems, amazing teachers, wise academics who can teach us at universities and all of the good stuff that we think of in a society, that does help drive cultural evolution forward, which then also has a positive knock-on effect in terms of biological evolution.
How the two are interlaced, biological evolution and cultural evolution is also really fascinating because it brings up all of these questions about the brain and exactly how we use the environment to affect our underlying biology. There's this amazing science at the moment about how the brain is a prediction machine, that's fundamentally what it is and it's constantly seeking out ways of predicting what's going on around it. And I just found that whole side of things quite interesting, especially in terms of emotions and how we create our own emotions through social constructs. I have a whole chapter on that. And also in the ways that we historically have measured intelligence and how they've been quite unsophisticated. And so there are all of these cultural phenomena that are not only driving brain evolution forward, I would argue, but helping us understand our brains much better than we have in the past.

Dr. Correa:
Is there an example of a culture or society in modern day now that maybe has a certain aspect of how they work as a community that is maybe improving their brain or the betterment of their society in a way that maybe we should think about modeling ourselves?

Dr. Joseph Jebelli:
I mentioned Finland in my chapter on emotion when I discussed happiness and I used Finland as an example because it ranked number one on the UN's 2021 World Happiness Report. And what they essentially measured discovered that the Fins enjoy basically the highest levels of income, life expectancy, social security, freedom of choice, freedom from corruption, generosity, trust, faith in the police and immigrant wellbeing, and all these different things essentially. And lots of social scientists and neuroscientists are trying to figure out exactly why this is. And I interviewed this really interesting professor of who specialized in emotion, Lisa Barrett Feldman, she wrote a book actually called How Emotions Are Made, which is really interesting. And she's quite interested in the Finnish population and trying to figure out exactly what they do in their society that boosts all of these measures and makes them arguably one of the happiest nations.
It comes down to, again, how we construct emotions and how things in our society can help us construct emotions for the good and for the bad. And there is something about the Finnish society and their culture that is helping them do that. I mean, they have a saying, they call it [foreign language 00:27:00], which means working collectively for a greater good, forming communities based on non-hierarchical principles. So things like that. That's a great example of a culture and a society using their behavior and their cultural evolution to actually change the chemistry of their brains, make them happier. I suppose that's one of the most interesting examples at the moment.

Dr. Correa:
It's so interesting that even in contrast, they have a culture and a society with the higher levels of happiness and probably more social infrastructure to support each other's happiness. Let's take it out of the broader society and culture and more into our closer home network. Separate from aging, can the brains of our partners and families members change over and during our relationships with them?

Dr. Joseph Jebelli:
I suppose it depends on how you define change. I'm a strong champion of minds changing and brains changing, even in adulthood. There's always a great debate about this in neuroscience because people say, "Well biologically the brain stops developing in your mid-twenties and so beyond that, it's quite difficult for brains to change." And there was this debate for a long time about stem cells in the brain only really being active in the young and then as you get older, you maybe can't replace neurons as well as you could. But then that's the thing I love about science, it's always making these great discoveries, which completely upend our understanding of things. So we know, for instance, because of the phenomenon of neuroplasticity, which is the brain's ability to literally rewire itself and rewire its synaptic connections in response to changing environments. We know that the brain has an extraordinary capacity to do that over someone's lifetime.
Neuroplasticity is the reason that you can learn a new instrument even when you are a fully grown adult and learn a new language and even recover from debilitating strokes. So because the brain does have this remarkable ability to change over our lifetime, I would say yes, everyone's brains can change for the better as well as the worse. And I suppose in terms of partners and your loved ones, we're always influencing each other. Again, why it's crucial for us to maintain very healthy emotions, be kind to each other and loving and forgiving and all of these things because it has a profound effect on us. I would make the case that our brains are far more malleable than we think they are.

Dr. Correa:
It highlights the importance of doing so many of these activities that support our overall brain health and still maintaining and stimulating our brains with activities and taking care of our emotional health. Thank you, Joseph, so much for taking the time today, sharing your perspective about your books and your experience with research.

Dr. Joseph Jebelli:
Thank you so much for having me. I've really enjoyed it.

Dr. Correa:
Thank you again for joining us on the Brain & Life podcast. Follow and subscribe to this podcast so that you don't miss our weekly episodes. You can also sign up to receive the Brain & Life Magazine for free Brainandlife.org.

Dr. Nath:
Also for each episode, you can find out how to connect with us and our guests along with great resources in our show notes. You can also reach out by email at blpodcast@brainandlife.org, and you can call in any time and record a question at 612-928-6206.

Dr. Correa:
You can also follow the Brain & Life Magazine, Audrey and me on any of your preferred social media channels.

Dr. Nath:
A special thanks to the Brain & Life team, including...

Dr. Correa:
Andrea Weiss, Executive Editor for Education and News Publications.

Dr. Nath:
Nicole Lussier, Public Engagement Program Manager.

Dr. Correa:
Rachel Coleman, our Public Engagement Coordinator.

Dr. Nath:
Twin Cities Sound, our audio editing partner. We are your hosts.

Dr. Correa:
Daniel Correa. I'm joining you from New York City and online @NeuroDrCorrea.

Dr. Nath:
And Audrey Nath, beaming in from Texas and on Twitter @AudreyNathMDPhD.

Dr. Correa:
Thank you to our community members that trust us with their health and everyone with neurologic conditions. We hope together we can take steps to better brain health and each thrive with our own abilities every day.

Dr. Nath:
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Exploring the Evolving Brain with Neuroscientist Joseph Jebelli

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