Instant Genius - What happens in our brains when we dream?

Episode Date: May 12, 2024

The chances are most of us will remember at least one dream we’ve had recently. But where do dreams come from, why is their content often universal across different cultures, and what can we learn from studying nightmares? In this episode, the first of a series of two, I speak to neurosurgeon and bestselling author Rahul Jandial about his new book This is Why You Dream: What your sleeping brain reveals about your waking life. We talk about what’s going on in the different areas of our brains when we dream, how the dreaming brain differs from the waking brain, and the intimate links that exist between our emotions, imagination and ability to dream. Learn more about your ad choices. Visit podcastchoices.com/adchoices

You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough. Enough to get lost! Or you could book a stay with Hilton. Welcome to your oceanfront room. Just steps from the water.

The Hilton sale is on 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. Kayak gets my flight, hotel, and rental car right, so I can tune out travel advice that's just plain wrong.

Bro, Skycoin, way better than points. Never fly during a Scorpio full moon. Just tell the manager you'll sue. Instant room upgrade. Stop taking bad travel advice. Start comparing hundreds of sites with kayak and get your trip right. Bad advice? You talking to me?

Kayak, got that right. When you need to build up your team to handle the growing chaos at work, use Indeed sponsored jobs. It gives your job post the boost it needs to be seen and helps reach people with the right skills, certifications, and more. Spend less time searching and more time actually interviewing candidates who check all your boxes. Listeners of this show will get a $75-sponsored job credit at Indeed.com slash podcast. That's Indeed.com slash podcast. Terms and conditions apply. Need a hiring hero? This is a job for Indeed sponsored jobs. 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, to learn more. Hello and welcome to Instant Genius, a bite-sized masterclass in podcast form. Each week 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.

The chances are most of us will remember at least one dream we've had recently. But where do dreams come from? Why is their content often universal across different cultures? And what can we learn from studying nightmares? In this episode, the first of a two-part series, I speak to neurosurgeon and best-selling author Rahul Jandiel about his new book, This Is Why You Dream, What Your Sleeping Brain Reveals About Your Waking Life. We talk about what's going on in different areas of our brains when we dream, how the dreaming brain differs from the waking brain and the intimate links that exist between

our emotions, imagination and ability to dream. So welcome to the podcast and thanks very much for joining us. So today we're talking about your book, Why We Dream, and you're a neurosurgeon. So I think a nice place perhaps we can start is to ask what's happening in our brains when we dream? That's a great place to start. The dreaming brain is only now being understood because in the last 20, 30 years, which overlaps with my training and my own career, is something that's quite different than the waking brain. So those two phrases, I think, are important that we have our waking brain and sleep slash dreaming brain.

And those are two distinct brain states. They can be discerned by electrical measurements through 96 stickers placed on the scalp and a recording called an EEG. There's a signature called sleep spindles that confirms somebody is asleep. So I think that's important because if we get into discussions about lucid dreaming and other things, that's a measurement that's important. And often I'll mention measurements and then interpretation or opinion. It's important because too often I think people say studies show and there isn't an explanation and there's oversimplification and sometimes too much of a statement that's concluded from an experiment that isn't thoughtfully set up. So if we accept that the waking brain and dreaming brain follow a 24-hour cycle roughly, then we can start to explore what is the waking brain versus the dreaming brain?

And to understand the dreaming brain, we must think about the waking brain. So the waking brain in general is set up to be in a task on mode, meaning we are dealing with the environment. We're taking in challenges. We are engaging the physical environment, the stresses that may happen. And this is done through a task-on phenomenon called executive network function. And so it's important that people not see the brain as something that's on off. The brain is always on.

It just modulates between different brain states, such as waking and sleeping, and also different networks within the brain play a role in determining your behavior and your perception. The executive network is not like a spot somewhere, but it's a collective of different anatomical regions that activate together to perform a function. So it would be different parts of an ensemble that activate to make a certain song. So these span the prefrontal cortex, and specifically a region called the DLPSC, which is dorsolateral prefrontal cortex, which is sort of if we had horns underneath them, it is wherever they would be. and it connects to other parts of the brain, such as the subcortical structures, such as limbic structures, as well as what people casually call the reptilian brain, which is the brainstem. So it relies on structures that are old and new, if you look at it from evolutionary point of view,

allowing us to have quick judgments as well as thought out judgments, right? To deal with what's going on in our environment, that executive network is usually dominant. When there is no challenge outside, when there is no task on, it's not like our brain hibernates or revs down like a computer waiting for somebody to hit the keyboard, pop back up into the executive network. The executive network, let's say, if it's 51% of the brain's metabolic consumption for the hypothetical situation, I'm just giving me numbers to make a point, then the other network that's relevant is called the imagination network. That's my phrase and other people are calling it that,

but the scientific word is default mode network. So when we're not engaging the outside world, there is no task we are on, then the imagination network, our internal mental workspace takes the dominant role, becomes 51, if you will, and executive network works becomes 49. In the dreaming brain, we are heavily imagination network.

there is no external task and that's the function of the dreaming brain the imagination network as well as the limbic structures which lead to sort of a hyper-emotional state potentially not every dream but emotional dreams can be very emotional during the dreaming brain because the executive network is dampened and part of the executive network is logic and calculation so there we have a dreaming brain and waking brain. We have the waking brain being executive network and the dreaming brain

being imagination network. We have the waking brain engaging the DLPFC dorsalateral prefrontal cortex for calculation, raw processing, logic, reason, and it's notably dampened when we dream.

Why that's important is the first pattern that I was able to connect and others have two is that when you look at, not your dream or my dream, but thousands of thousands of thousands of dream reports and surveys and questionnaires, math is very rarely reported. And that when you look at the dreaming brain with a dampened dorsolateral prefrontal cortex

responsible for calculation, kind of makes sense. That region is not throbbing, if you will, with activity. And so dream reports are consistency lacking in it. Not that a few of your listeners won't say like, oh, I do have dreams about math. I'm not contesting that. I'm not, I'm just saying that you start to see some patterns. in dreaming, you see some patterns of what we dream can be explained by how the dreaming brain works. So you mentioned their emotional dreams. I mean, is it possible to split the content of our

dreams into different categories? I think so. And that's chapter nine in the book. And what I would say is let's give dreaming the same courtesy we would offer waking thought. Not everything we think about and talk about during the day is worthwhile or useful or interesting or need to be held on to. So I think there is dreaming activity that dreams are sort of the thoughts and experiences and emotions our dreaming brain creates that lean heavily visual, that lean heavily emotional when they are that. Sometimes they're just nothing. Sometimes it's just static, if you will.

And much of our day, we have things that we don't remember. So that's one type of dream. But in chapter nine of the book, I think dreams for me can be broken. down into five general types based on how to decipher them. That's my take on it. This is not something I'm reporting from others. Those who have tried to categorize dreams, the list goes on indefinitely because dreams are near infinite.

And I say near infinite because we rarely do math in our dreams. So we see some patterns. There are some boundaries to dreaming determined by the dreaming brain. But if you look at general categories, there are those dreams that make sense because they reflect the daytime anxiety. You have a, for example, you have a speech you're going to give and you have a dream about showing him naked to the podium. You have an exam, you have a dream about being late for it. You know, that reflects our waking anxiety is reflected in the dream.

Then there are these genre dreams where I'm a cancer surgeon, a cancer neurosurgeon. I sub-specialize in that, you know, as well as a neuroscientist. I have a laboratory where we grow neurons and different things, dual trained as a neurosurgeon with an MD neurosurgeon and a PhD neuroscientist. And so when I take care of cancer patients at a cancer center, those that are nearing the end of their journey, they often have what are called genre dreams, expansive dreams with reconciliation often, not always, with a reflection back on their life. Not always, but you start to see some patterns that the dream is sort of their shepherd and partner through the intense process of their life. Similarly, pregnant people will have dreams about, you know, baby. being smothered in bed and anxieties that reflect becoming a new mom, if you will. So again, those don't need to be deciphered. They are reflecting, waking anxiety, waking concerns.

Then there are the third to hype or fourth, if you put the dreams that are not meant to be looked at any deeply as number one. This would be the number four is, are there universal dreams that almost all of us have had a nightmare. I don't need to explain a nightmare. to you or me, I've had to explain them to my sons, who are now 18, 19, and 22, but there was a time in their cognitive development. I had to tell them, it was only a nightmare son. And that makes me wonder at that time, did they not know the waking thought and dreaming thought were distinct? So that's an interesting aside, but nightmares and erotic dreams are universal dreams.

They arrive for all of us, essentially, when the numbers get above 90% in the statistics of medicine, it's nearly universal. And then the last one is what I called, you know, sort of the deeply emotional dreams that leave a residue. I think those are the ones to interpret. Not because it'll always make sense, but if we have accepted there's a waking brain, a dreaming brain. If we've accepted that the biology that's measured, the neurobiology of the dreaming brain, is the top speed of emotion. The hyper-emotional state in the dreaming brain has a higher top speed than the waking brain can ever achieve. Then any thoughts or emotions or feelings or residue of dreams you may have and memories you may

have that are hyper-emotional, they offer at least an insight to yourself that is not available during your waking life and insight into yourself or an opportunity for self-reflection that a therapist can't offer unless you share that dream with them. And so those are the ones I think that are the precious dreams that are portal to ourselves that I try now to reflect on more than I did in the past. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building.

Fit for your ambition for Citizens Bank. It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speeds. That's why I chose GoogleFi wireless. My connections stay strong, when the hive is buzzing. Plus, unlimited plans started $35 a month. Now, that's a deal that doesn't stay.

Explore GoogleFi Wireless plans today. Plus taxes and government fees, GoogleFi Wireless is not subject to data traffic deprioritization during times of high network usage. This podcast is sponsored by Name, Audio, and Focal. With over 100 years of combined expertise, Name and Focal have been bringing music to listeners just as the artist intended. Since day one, this mantra has shaped every innovation in hi-fi design, technology and acoustic engineering, balancing craftsmanship and tradition with pioneering thinking. Name Audio pushes cutting-edge technology to ensure digital precision whilst sustaining Pratt, pace, rhythm and timing, the elusive quality that makes music feel alive and gives it emotional texture. Today, in partnership with French acoustic specialist's focal, name audio creates systems that deliver exceptional sound

and unforgettable listening experiences at home. Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. Yeah, so you mentioned an exam anxiety scenario there. And one recurring dream I have is that I'm going to sit in an exam and I haven't prepared for it. And I think this is really strange because I've never actually done that in my life,

and I haven't taken an exam for more than 20 years. Yeah. So how come my brain seems to be obsessed with this? The way to explore that is, because they're hyper-emotional and illogical by design of how the dreaming brain functions, they're often metaphorical and symbolic. So people who are veterans of wars

when they're going through a divorce, have dreams of the war, rather than dreams of the divorce, the anxiety is released or reflected in a symbolic way. That would be my explanation or my attempt at an explanation that also kind of hints to why, even if we've never fallen, we have dreams of falling. These aren't universal dreams. They're not rare dreams like math. They're not universal dreams like nightmares or erotic dreams.

But there are common dreams that have spanned not just our lifetimes, but generations in different cultures. dreams of falling, dreams of being chased, teeth falling out. And I think they are symbolic of something. The fact that we all share them, I think, indicates that there's a cognitive inheritance. We don't just inherit our ancestors or parents' physical traits, if you will. We are inheriting some cognitive features as well. Some have something, you know, disposition to risk or mental health follows, not just genetic. because it's beyond genetics.

There are things like epigenetics. They're heritable patterns, not invariable, not constant. But when you look at nightmares, they can nightmare disorders, they can cluster in families. That's fascinating to me that not dreams of falling or teeth falling out, those don't cluster in families, but nightmares do. So I think that the fact that we have dreams, and maybe you've never been stressed out by an exam, or maybe you've even taken an exam, but people still have dreams of falling and being chased and exams because the dreaming brain releases emotions and generates images and creates experiences

that are metaphorical and symbolic of something. And so being stressed out about an exam is an anxiety-provoking experience your mind has released while dreaming. And then the question becomes, is that an indicator of some stress you were feeling during the waking day, during your waking life? and then the question becomes, if it's not, then it's not. But sometimes changes in dream patterns can be a harbinger or a warning flare of something you are experiencing, yet not cognizant of, during the day. So you've mentioned nightmares a couple of times there. I've heard nightmares

called before The Mother of All Dreams, which I thought was quite an interesting idea. So what's your take on nightmares, you know, what's their function? This is a profound question, because I try to explore this with neuroscience depth, but I also want to be able to discuss it if I'm at a pub or if I'm talking to my teenage sons or we're just having a proper chat, as you say, here in the UK, you know, just a conversation. And the first thing in a conversation that comes up is,

all right, you think you're exploring the science of dreams and dreaming. Surely nightmares are a mistake. That's a glitch of the human mind, or that's a flaw in the dreaming process. That's why I made it chapter two in the book. I wanted to take on the bigger theme here. The way I've come to understand nightmares is to think of them as pediatric and adult.

Two types. Children have nightmares. Nightmares arrive for children invariably around age, four, five, six, seven, eight, something like that. And then they fade. And they go away for nearly all kids. Despite all of us having nightmares as a child,

very few of us have nightmares as an adult. They come as a certain wave. and this is a conceptual answer. The nightmares in adults is more readily grasped because I think is more of a psychological thermometer of ongoing stress. So we'll get to that, but back to pediatric nightmares, back to nightmares and children, if you will.

This can never fully be understood, but there's some very interesting findings through cognitive neuroscience. One, nightmares arrive at the same time a certain feature of the mind is being developed. And that's called the theory of, mind. It's a phrase you can look it up. It's when children learn to read other minds that somebody's smile may be disingenuous, right? Just because they're smiling doesn't mean they're happy.

Because they're smiling doesn't mean they mean as well. The capacity to put yourself in other people's minds from their perspectives requires a sense, I think, of realizing a sense of self versus other. And maybe a hypothesis for the arrival of nightmares is it forges our sense of identity and sense of self. Because it arrives at the same time as those features are developing in our kids' minds. The arrival of nightmares

parallels the development of theory of mind. Just like we learn to walk and talk, the theory of mind is cultivated. You're not born with it. And also, nightmares serve as sort of the most obvious example

to teach a child or remind a child. It was only a dream. So does that mean children don't know waking thought versus dreaming thought until nightmares make us startlingly obvious, because part of nightmares is that they must wake you up and sear your memory. They're not like every other dream or they fade into the background. They wake you up and you remember the events searingly. It seems to me that something that we all experience around the same time, that fades is a part of our cognitive maturation, much like learning to walk and talk. So that would be my big idea.

And that happens when children have never seen monsters or talked about the gentleness of rearing for children, yet they still imagine and see monsters. Now, when they see animals, they don't report pets. They report beasts or creatures and animals. It's a very interesting finding. And the fact that nightmares cluster in families makes me wonder, and there's a field of evolutionary psychology, that maybe nightmares serve a function in the development of young mind. Now let's jump to adult nightmares. The occasional nightmares often reported is not a big

deal. The nightmares in adults that we all hear about are PTSD-related nightmares. Those are flashbacks. Those nightmares are not a product of the imagination. They are actually a traumatic event that continues to replay and stamped with an emotional imprint, so it's hard to forget. And when the replay happens, it often activates visceral responses that are sturdily. and troubling, right? And then there's the imagined nightmare in adults. These nightmares, to me, are sort of a psychological thermometer. The occasional adult nightmare, I think, does not indicate anything, but new onset nightmares.

That's a phrase where you don't really have nightmares. You have them once in a while, but now you're getting them all the time. They've come out of blue, and they're increasing, they're going up, you're having them more and more. I think that's something to pay attention to, much like we were at a rising body temperature or we would a headache that won't go away and gets worse. And why that's important is, I think it can reflect mental health concerns during your waking life that you have yet to identify. So one, they can be a warning flare. And then two, in some very specific ways, return of nightmares, at least in some neurodegenerative diseases like Parkinson's, is sort of the

earlier sign or a true warning flare. And so nightmares to me and adults are a thermometer for the mind, if you will. Not always, not every time, but the fact that they are sometimes, I think, is fascinating and it's powerful and something for us to consider. Thank you for listening to this episode of Instant Genius. Brought to you from the team behind BBC Science Focus. That was Rahul Jandaiil. Discover more about the topics we've just discussed, check out his latest book. This is Why You Dream, what your sleeping brain reveals about your waking life. If you liked what you just heard, please consider subscribing to Instant Genius on your preferred podcast platform. The current issue of BBC Science Focus magazine is out now.

Pick up a copy wherever you buy your favourite magazines or download a copy on your app store of choice. You can also find us online at sciencefocus.com. This podcast is sponsored by name or 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 nameadio.com. When the job gets tough, you need equipment that's built to handle it.

The Cabota Construction lineup, featuring the versatility to do more, durability to keep going, and increased comfort for long days on the job. With skid steers, track loaders, wheel loaders, utility vehicles, and the world's number one selling compact excavator for 20 years, our expanding lineup is built to deliver. Visit CabotaUSA.com or your local Cabota dealer today to learn more. Go to CabotaUSA.com slash disclaimers for full display. In a place like Los Angeles, people don't stop being who they are.

Writers, thinkers, creators, people with stories still unfolding. That spirit lives on at Kingsley Manor, a community shaped by individuality, creativity, and lives well-lived. So when the conversation turns to what's next, it isn't about stepping away. It's about continuing the story. Explore your options at kingsley Manor.org, a nonprofit month-to-month senior community. within the Front Porch family.