Speaker 1: Sleep.
Speaker 2: We spend around a third of our entire lives doing it,
Speaker 2: completely oblivious to the world around us. Some animals, like cheetahs, toads,
Speaker 2: and squirrels, spend at least half of their lives asleep.
Speaker 1: It's kind of baffling when you think about it.
Speaker 2: Time spent sleeping is time that can't be spent doing
Speaker 2: things like searching for food, and if you're a wild animal,
Speaker 2: time spent sleeping is time when you're less able to
Speaker 2: detect a predator in the area.
Speaker 1: So why do we sleep?
Speaker 2: It turns out this activity that swallows up so much
Speaker 2: of our short time on this planet is really hard
Speaker 2: to study, but scientists have made some headway on this
Speaker 2: question of why do we sleep? And today we're going
Speaker 2: to talk to doctor Gina Poe about why we sleep
Speaker 2: and chat with her about other fascinating questions like do
Speaker 2: mushrooms sleep, does an octopus dream? And does all all
Speaker 2: of our brains sleep at the same time or do
Speaker 2: some parts fall asleep before the others?
Speaker 1: Welcome to Daniel and Kelly's Sleepy Universe.
Speaker 2: Hi.
Speaker 3: I'm Daniel, I'm a particle physicist and I don't sleep
Speaker 3: particularly well.
Speaker 1: Hi I'm Kelly Wiersmith.
Speaker 2: I study parasites and space, and I'm not gonna blame
Speaker 2: it on the parasites. But I don't sleep very well either,
Speaker 2: But I love sleep, Like when eight to thirty comes
Speaker 2: around every night, it is like the only thing on
Speaker 2: my mind. Zach is like, it's only a thirty Are
Speaker 2: you going to pull an all niner and stay up
Speaker 2: past nine? And I'm like, I'm gonna do everything I
Speaker 2: can and be in bed by the time nine o'clock
Speaker 2: rolls around.
Speaker 3: Young people don't appreciate how nice it is to be
Speaker 3: home in the evening and have no plans, I.
Speaker 2: Know, and have a comfy bed. Ah the blessing that
Speaker 2: is a comfy bed. It's one of my favorite things.
Speaker 4: It is.
Speaker 3: Yes, when sleep well, it is definitely one of the
Speaker 3: best things in the world. But when it's fraught, man,
Speaker 3: I've had nights that lasted a thousand years.
Speaker 1: Oh my gosh. Yeah, no, me too.
Speaker 2: We went camping once and it was a little bit
Speaker 2: rainy and wait, so we weren't really camping. My daughter
Speaker 2: and I were sleeping on the trampoline and it started
Speaker 2: to rain and then it got really cold, and then
Speaker 2: my back hurt. But I didn't want to ruin the
Speaker 2: night for her, and so I tried to make it work.
Speaker 2: And then at like five am, I was like EIGHTA,
Speaker 2: we're moving inside.
Speaker 1: I needed a nap. This is miserable.
Speaker 3: Well, it's amazing to me that sleep is something we
Speaker 3: just cannot do with that that we have to accomplish
Speaker 3: every single day, and also that it's something you can't
Speaker 3: really try to do. It's like something you have to
Speaker 3: try to not do, you know though, Like the harder
Speaker 3: you work at sleeping, the more you get worked up
Speaker 3: about it, and the harder it is too sleep. It's incredible.
Speaker 3: It seems so fragile. It's incredible that it ever works.
Speaker 3: I don't know.
Speaker 2: Yes, I think you and I are making clear that
Speaker 2: we don't have a very good relationship with sleep at all.
Speaker 1: But I wake up a million times in the middle
Speaker 1: of the night, and it's a.
Speaker 3: Thing, and it makes me wonder, like why we evolved this,
Speaker 3: why it's such an important part of our life cycle?
Speaker 3: If it's yet so fraud and so fragile, right, it
Speaker 3: seems like kind of a bad idea.
Speaker 2: I mean, I think it's possible that you and I
Speaker 2: are just broken in a particular way. And that this
Speaker 2: problem with sleep is not present for everyone. I mean,
Speaker 2: my kids conk out and they are out and it's
Speaker 2: fine for them.
Speaker 3: But that's also an age depending thing, right. A lot
Speaker 3: of kids have no problem with sleep, sleep all night,
Speaker 3: sleep anywhere, all the time. But then as you get
Speaker 3: older sometimes it gets harder to make it work.
Speaker 1: I agree.
Speaker 2: But so today's episode, we're talking to a sleep experts
Speaker 2: and we forgot to ask her about tips for how
Speaker 2: to solve our sleeping problems. She didn't solve our sleep problems, yes,
Speaker 2: but a guest wanted to know about dreams, why we dream,
Speaker 2: interpretations of dreams, et cetera. So, what is the weirdest
Speaker 2: dream you've ever had?
Speaker 1: Daniel?
Speaker 2: And let's keep it short, because I think notoriously people
Speaker 2: don't want to hear about dreams that other people have had.
Speaker 2: So real, quick, weirdest dream you've had?
Speaker 3: Well, as you know, I think a lot about aliens,
Speaker 3: and so lott of my weird dreams have aliens in them,
Speaker 3: and they're pretty weird and sometimes they eat me or
Speaker 3: my children, and sometimes it's my fault. Oh no, And
Speaker 3: so yeah, those are pretty weird dreams.
Speaker 2: There are so many insights about you wrapped up in
Speaker 2: that story. For me, it was my mom and I
Speaker 2: teamed up with the Berenstein Bears. We were a crime
Speaker 2: fighting organization and a murderer was on the loose and
Speaker 2: the murderer killed me because my mom, you know, went
Speaker 2: off down a hallway and we split up, which classically
Speaker 2: you should never do, and the Berenstein Bears had gone
Speaker 2: another way and anyway, big mistake. Yeah, But all right,
Speaker 2: So I don't know that there's much you can extract
Speaker 2: about me out of that dream in particular, but we
Speaker 2: are going to talk to an expert on sleep and dreams,
Speaker 2: doctor Gina Poe, and she's going to answer all of
Speaker 2: our questions about sleep and dreams.
Speaker 3: And she's going to blow your mind about what it
Speaker 3: means to sleep across the animal world.
Speaker 2: And so let's start by listening to the question from
Speaker 2: our listener that got this whole interview started.
Speaker 4: Hi, Daniel and Kelly. This is Carrie from the Pacific Northwest,
Speaker 4: and I was wondering if you can do show on dreams,
Speaker 4: why we dream, what part of our brain is being
Speaker 4: used when we dream, and just everything about dreams.
Speaker 3: Thank you, thank you Kerre for that wonderful question, and
Speaker 3: all of you out there listening, if you haven't already
Speaker 3: fallen asleep to this podcast, you are welcome to send
Speaker 3: us your questions about the universe. We will try to
Speaker 3: answer them, and we will sometimes rope in a world
Speaker 3: class expert to give you answers.
Speaker 2: And let's bring that world class expert on now. On
Speaker 2: today's show, we have doctor Gina Poe. She's the Eleanor
Speaker 2: Leslie Professor of Innovative Brain Research at UCLA. In addition
Speaker 2: to research, she directs three university programs aimed at supporting
Speaker 2: undergraduates who are underrepresented in STEM fields. She's done so
Speaker 2: many incredible things. I'm just going to cherry pick a few.
Speaker 2: Gina and her colleagues sent four rats to space as
Speaker 2: part of NASA's Neurolab mission to study how brains map
Speaker 2: the three D world in weightlessness where you don't really
Speaker 2: know what side is up. And she's well known for
Speaker 2: her discovery that's is important not just for remembering things,
Speaker 2: but also for forgetting things. Her lab at UCLA focuses
Speaker 2: on sleep and memory, which are the topics we're going
Speaker 2: to be chatting about today. Welcome to the show, doctor Poe.
Speaker 5: Thank you so much. It's great to be here.
Speaker 1: We're super excited, Gina.
Speaker 3: I have a first question, which is sort of goofy,
Speaker 3: which is what do you call a rat you send
Speaker 3: into space? Is it a ratronaut?
Speaker 5: Yes? Actually great?
Speaker 3: And do they have to undergo like a rigorous selection
Speaker 3: process you know where they like run on treadmills for hours?
Speaker 5: Actually yes, yes, we started with forty rats and ended
Speaker 5: up before so and.
Speaker 3: Those were the four that had the rat stuff.
Speaker 5: Yeah, the rat stuff nice, amazing great.
Speaker 2: Okay, so let's start big with why do we think
Speaker 2: we sleep? And how well do we understand the answer
Speaker 2: to this question.
Speaker 5: There are lots of answers to that question. I think
Speaker 5: that there probably is one essential reason why we sleep,
Speaker 5: but we don't know the answer to that question. But
Speaker 5: we do know a lot of essential things that happen
Speaker 5: during sleep with which we can't do without. For example,
Speaker 5: energy metabolism goes way up when we're asleep. What I
Speaker 5: mean by that is not actually metabolism, I mean restoring
Speaker 5: energy stores to our entire body. Our mitochondria wake up
Speaker 5: when we go to sleep, and they are doing their
Speaker 5: job much much faster and restoring atp to all of
Speaker 5: our cells. So that's just one essential function of probably
Speaker 5: twenty that we know of.
Speaker 3: Why do we have to be asleep for mitochondria to
Speaker 3: do that? Why can't they just do it while we're
Speaker 3: doing our thing?
Speaker 5: I don't know. That's a good question. That's actually a
Speaker 5: fairly new discovery.
Speaker 1: And is that happening in all of our cells or
Speaker 1: just our brain cells.
Speaker 5: It's been discovered in fruit flies brain cells. Okay, so
Speaker 5: that's a good question. I imagine it's going on everywhere.
Speaker 5: But we know that the longer we're awake, the more
Speaker 5: free adentiicine builds up in our brain, and that free
Speaker 5: adenticine is a signal for sleepiness. And as soon as
Speaker 5: we go to sleep within thirty minutes, that freodentisine has
Speaker 5: been repackaged by mitochondria into ATP. So the freodentisine levels
Speaker 5: go way down when we're asleep in the first twenty minutes,
Speaker 5: which is probably why power naps are called power naps.
Speaker 2: I do love me a power nap, me too. And
Speaker 2: now I feel way more justified in that you said.
Speaker 3: There are like twenty different things that happened when we sleep.
Speaker 3: One of them is we're restoring energy stores. What are
Speaker 3: some of the other ones.
Speaker 5: Okay, so well, we know that we consolidate memories when
Speaker 5: we're asleep, that's my field of research, and that without sleep,
Speaker 5: we don't put them away long term and our memory stories.
Speaker 5: Of course, memory is really important for adaptation to our environment,
Speaker 5: finding where our home is, et cetera. And so that
Speaker 5: would you can imagine that would be important for life itself.
Speaker 5: It doesn't seem like all animals should have to learn things,
Speaker 5: but in fact, every time we've tried to teach any
Speaker 5: animal something, they've been able to learn it. Even mushrooms
Speaker 5: can learn it. And there's some interesting study by vlad
Speaker 5: Vyazovsky that shows that even mushrooms need sleep.
Speaker 1: Well, what does sleep look like in a mushroom?
Speaker 5: Like, what are they missing exactly? I don't know, you'll
Speaker 5: have to ask Glad, but it came up with a
Speaker 5: very convincing argument that mushrooms do sleep.
Speaker 2: Oh wow, okay, so then that I'm going to jump
Speaker 2: ahead then to another question that I had before, we
Speaker 2: go back to purposes of sleep. Okay, so I would
Speaker 2: not have guessed you were going to tell us that
Speaker 2: mushroom sleep. That's an amazing surprise. I'm going to try
Speaker 2: sneaking up on some of the mushrooms in my yard.
Speaker 3: Now, Kelly, they're busy consolidating their memories of the day.
Speaker 3: You're going to ruin it for them.
Speaker 1: I'm sorry.
Speaker 2: I know all the tricks they were trying to learn. So, so,
Speaker 2: what organisms sleep or like? Maybe it sounds like the
Speaker 2: better question is what organists don't sleep, given that even
Speaker 2: mushrooms sleep, Like, do bacteria sleep?
Speaker 5: That is a good question. They definitely have a circadian rhythm,
Speaker 5: so they have a time when they're not actively pulsing
Speaker 5: or whatever and times when they are. So yeah, it's
Speaker 5: a good question. I don't know the answer to that one,
Speaker 5: and it would be difficult probably to tell in bacteria
Speaker 5: except for that sort of change in activity. I guess
Speaker 5: it would be the only way you could tell. Certainly,
Speaker 5: our gut bacteria are doing different things at night versus
Speaker 5: the day, and their rhythm gets messed up when we
Speaker 5: have jet lag, for example.
Speaker 3: And in all these creatures that sleep, is it all
Speaker 3: linked to the same day night cycle.
Speaker 5: Yes, except that, for example, there are rats and mice
Speaker 5: who sleep during the day. So there are some things
Speaker 5: that are flipped. The switch is flipped. But even for
Speaker 5: rats and mice, Melatonin, which is the hormone of darkness,
Speaker 5: is higher during the night when they're awake and active.
Speaker 3: So I have a question based on a tiny amount
Speaker 3: of anecdotal data. When I go to sleep, my dog
Speaker 3: is in one place, and if I ever wake up
Speaker 3: in the middle of the night, he's sleeping in another place,
Speaker 3: And in the morning he's in a third place because
Speaker 3: he has like nineteen different places he likes to sleep
Speaker 3: in our house. Okay, so my question to you is
Speaker 3: what is my dog doing all night? Does he just
Speaker 3: take naps and then move around? Is he, like, you know,
Speaker 3: up learning how to make souflets in the middle of
Speaker 3: the night. Like, why don't dogs sleep all the way
Speaker 3: through the night? What's going on in my house? Gina?
Speaker 5: Tell me dogs and cats predators actually sleep a lot
Speaker 5: more than prey species do. They sleep about sixteen hours
Speaker 5: a day in a nice home environment. So, yes, your
Speaker 5: dog is waking up more than you do, probably at
Speaker 5: night and maybe going to get some water or just
Speaker 5: checking out the house and finding a cooler place to sleep.
Speaker 5: But if you were to put a camera on your dog,
Speaker 5: your dog isn't roaming around and hunting like a cat.
Speaker 5: A cat is more crepuscular, so they have a lot
Speaker 5: of activity in the morning and in the evening, but
Speaker 5: they sleep a lot during the day, and they sleep
Speaker 5: a lot during the night as well. But dogs are
Speaker 5: a lot more diurnal like we are. So, yeah, your
Speaker 5: dog is pretty much rest assured, sleeping all night, just
Speaker 5: getting up once in a while when they're uncomfortable or
Speaker 5: they're done with the sleep cycle.
Speaker 3: I was kind of hoping he was writing like the
Speaker 3: great American novel in the middle.
Speaker 2: Yes, so my brain is a little bit stuck on
Speaker 2: the mushroom thing, and it's making me wonder how do
Speaker 2: we define sleep? Because you know, I thought maybe we
Speaker 2: would define it by like brain waves or things that
Speaker 2: you wouldn't be measuring in a mushroom. So let's let's
Speaker 2: step back even farther than how do we define sleep?
Speaker 5: Yeah, so there are animals we can't define sleep via
Speaker 5: brain waves because their brain isn't organized the same way
Speaker 5: ours is. In order to be able to see those
Speaker 5: brain waves, we have to have an alignment of neurons,
Speaker 5: because each neuron has you know, a t any little
Speaker 5: electrical signal, and when they're all aligned in the same orientation,
Speaker 5: you can see that electrical signal sums, and we can
Speaker 5: see it from a place as distant as the surface
Speaker 5: of your scalp. There are three layers of skin, four
Speaker 5: layers of skin actually between your actual brain cells and
Speaker 5: the electrode, plus bone and water. So you can imagine
Speaker 5: that that signal would be reduced the further distance you
Speaker 5: are away from your brain.
Speaker 3: So that's what brain waves are. Sorry to interrupt, I
Speaker 3: just I've always wondered brainwaves are measurement of the electrical
Speaker 3: field caused by firing neurons.
Speaker 5: Yes, exactly. They actually don't even have to fire. The
Speaker 5: membrane potential just has to depolarize or hyperpolarize so become
Speaker 5: more positive or negative.
Speaker 3: It's amazing there's any signal in there at all. Yeah,
Speaker 3: why are the neurons oriented physically in the same way
Speaker 3: so that they can constructively build a signal? That's incredible.
Speaker 5: Yet why is a great question. I don't know the
Speaker 5: answer to that, but they are the biggest neurons in
Speaker 5: our brain. Are these things in our cortex called pyramidal cells,
Speaker 5: which are shaped like pyramids, which is why they're called
Speaker 5: parametal cells, And they are just oriented on the folds
Speaker 5: of our brain facing outward, and there are tufts of
Speaker 5: antenna at every pole of the pyramid, and the ones
Speaker 5: at the base are called baseler dendrites, and the ones
Speaker 5: at the top are called aprical dendrites. And the apical
Speaker 5: dendrites are the ones that reach all the way to
Speaker 5: the very surface of our brain, and they are the
Speaker 5: ones that get communication from other areas of our cortex.
Speaker 5: So when we're thinking thoughts, that's all come again our
Speaker 5: apical dendrites. When we're feeling feelings that are coming from
Speaker 5: the outside, like our sensations, they come in at the
Speaker 5: baselin drites, and the ones that are closest to the
Speaker 5: apical dendrites, not the distant ones, So they're just all
Speaker 5: aligned like that in our stray of our cortex, or
Speaker 5: as you've probably seen them, they're folded. So it's only
Speaker 5: at the top of those striations that you can get
Speaker 5: the electrodes and see what's going on. So we can
Speaker 5: with our electrical EEG electrodes, you can only see a
Speaker 5: small percentage of what's going on in our brains, and
Speaker 5: only what's at the surface because as the distance increases,
Speaker 5: the signal decreases. Exponentially.
Speaker 2: Yeah, and so we use that information to define sleep
Speaker 2: in organisms where that works. Yes, is that otherwise what
Speaker 2: kinds of things would we be looking for in organisms
Speaker 2: that have a more like distributed nervous system where it's
Speaker 2: harder to do that kind of stuff.
Speaker 5: Yeah, So organisms like the octopus, it has more ganglia, like,
Speaker 5: it doesn't have a cortex like we have. And so
Speaker 5: the neurons are there, of course they're there. They are
Speaker 5: all over their legs and central brain area, but they're
Speaker 5: organized in very kind of more random fashion. So even
Speaker 5: though they're just as electrically active as ours our, the
Speaker 5: electricity you know, is going in different directions and so
Speaker 5: it doesn't summate, so we can't really see them with electrodes.
Speaker 5: So instead we need behavioral measures. And so animals usually
Speaker 5: have a typical sleeping position or positions. Even the sea
Speaker 5: elegans worm has this typical sleeping position and they sleep
Speaker 5: like it's called a shepherd's hook. It looks kind of
Speaker 5: like a question mark. That's their sleeping position. It's kind
Speaker 5: of cute. Yeah, it's really cute. And then they're all
Speaker 5: these animals are less sensitive to what's coming in from
Speaker 5: the outside, so I wouldn't suggest this, but you can
Speaker 5: tap on your fish tank at night and the fish
Speaker 5: won't respond the same way that they respond during the day.
Speaker 5: During the day they'll respond right away and swim around,
Speaker 5: but at night they'll just sit there and maybe a
Speaker 5: few seconds later they'll sort of arouse and respond. So
Speaker 5: they're less responsive to the outside world. But it is
Speaker 5: a reversible state. To determine and distinguish it from coma,
Speaker 5: it's homeostatically regulated, which means that all animals that you
Speaker 5: deprive of sleep will try and get more sleep the
Speaker 5: next opportunity they have. So there is a great study
Speaker 5: of jellyfish, which don't have a central nervous system either
Speaker 5: at cal Tech that showed that these cassiopeia, which are
Speaker 5: these upside down jellyfish sleep at night like we would expect,
Speaker 5: and what they do is they find the bottom of
Speaker 5: the tank or whatever they find something to rest on
Speaker 5: to sleep, and then they just start pulsing more slowly.
Speaker 5: And then if you wake them up a bunch of
Speaker 5: times at night by giving them a jet of water
Speaker 5: or something to deserve them from their sleeping position, they
Speaker 5: will wake up, pulse faster, try and find the bottom
Speaker 5: again and go right back to sleep. And if you
Speaker 5: do that all night long, the next day they'll map
Speaker 5: a lot more. WHOA, I know.
Speaker 3: Do you need some sort of ethics review to torture
Speaker 3: these jellyfish this way all night long?
Speaker 5: You know?
Speaker 3: Is that a yes or no?
Speaker 5: I wasn't sure, no, but thankfully not.
Speaker 2: How many people are doing this so if they had vertebrae,
Speaker 2: you would have to yeah, right, exactly exactly.
Speaker 3: Oh, I see, So rats have ethical protection, but jellyfish
Speaker 3: you can torture as much as you like all their
Speaker 3: larve right right.
Speaker 2: Wow, we would not call it torture, Daniel, the physicists.
Speaker 3: I'm trying to speak here on behalf of the jellyfish.
Speaker 3: This sounds like torture to me. You come in my
Speaker 3: room and wake me up ten times a midd of
Speaker 3: the night, I'm not going to be very pleasant the
Speaker 3: next day. I'm going to do more than just nap,
Speaker 3: I'll tell you that much.
Speaker 5: Yeah, you can't get their consent with people. You know,
Speaker 5: you get people volunteering for these kinds of studies all
Speaker 5: the time, and yeah it's not great, but they you know,
Speaker 5: they like contributing to our knowledge of what sleep is
Speaker 5: about and seeing what their own sleeper is like. We
Speaker 5: can't give the same feedback to jellyfish, but we do
Speaker 5: allow them to sleep the next day nop as much
Speaker 5: as you want. You can also give them caffeine. It
Speaker 5: works the same way. It keeps them up and makes
Speaker 5: them more active. Interestingly, in that study of jellyfish sleep,
Speaker 5: they found that they pulse more slowly at night. If
Speaker 5: you wake them up, they pulse faster. But in a
Speaker 5: I think it was figure two of that paper they
Speaker 5: don't even describe. There are periods of time when they're
Speaker 5: not pulsing at all, which is, you know, like not
Speaker 5: breathing essentially for twenty or thirty seconds at a time,
Speaker 5: and that could mirror the second stage of sleep, which
Speaker 5: I'm sure we're going to get into later, which is
Speaker 5: our dream stage at sleep, and in order to not
Speaker 5: act out our active dreams, we actively inhibit all of
Speaker 5: our muscles, not our breathing muscles, thankfully, not our heart muscles, thankfully,
Speaker 5: but all of our anti gravity muscles, so that we
Speaker 5: are acting out our dreams. And it seems like jellyfish
Speaker 5: have the same kind of called atonia no muscle tone,
Speaker 5: that we have, and they do it periodically throughout the night.
Speaker 5: The authors of that paper didn't describe a second state
Speaker 5: of sleep for jellyfish because I guess they just wanted
Speaker 5: to avoid controversy, or maybe they had it in the
Speaker 5: original draft and reviewers just said you need more evidence.
Speaker 5: But also spiders and octopus they all have this second
Speaker 5: stage of sleep. And when spiders have atonia, what do
Speaker 5: you imagine that they look like?
Speaker 1: Do they look like the dead dried up?
Speaker 5: Yes? Really they do.
Speaker 2: Wait, so like if I find a black widow in
Speaker 2: my garage and it's all dried up, it might just
Speaker 2: be sleeping and not dad.
Speaker 5: It might just be sleeping.
Speaker 2: Oh interesting, that's a little scary.
Speaker 5: Okay, it might be in that RAM sleep. Now. We
Speaker 5: call it ram sleep in humans because we have rapid
Speaker 5: eye movements and that corresponds with our dreaming. Actually, spiders
Speaker 5: also have rapid eye movements during that state.
Speaker 1: And do all of their eyes move?
Speaker 5: Yeah, their eyes move. You can only see it in
Speaker 5: very young spiders where they don't have the dark yet coloring,
Speaker 5: so you can see through their carapace and see their
Speaker 5: eyes moving and also coolly. When we're in rams sleep,
Speaker 5: our eyes don't always move conjointly like if they do
Speaker 5: when we're awake, so we could have one eye moving
Speaker 5: this way and it's just not for some reason. Maybe
Speaker 5: our brainstem areas that are helping our eyes track the
Speaker 5: world are not coordinated when we're in reun sleep. And
Speaker 5: that's true at spiders as well. So during wakefulness their
Speaker 5: eyes move together in a ram sleep state, which we
Speaker 5: can call rams sleep, and spiders, because their eyes are
Speaker 5: also rapidly moving, their eyes don't move conjointly. In cockroaches
Speaker 5: they have rapid intennel movement sleep, so they're antenna well
Speaker 5: you know, hu jiggle.
Speaker 3: That almost sounds cute wow.
Speaker 5: And bees as well. Bees will have rapid intennel movements sleep.
Speaker 2: And do we have evidence for these animals that they're
Speaker 2: also consolidating memories while they're sleeping or do we think
Speaker 2: they're doing something different.
Speaker 5: I don't think they're doing something different, for example, in
Speaker 5: the act, so they don't. Actually I don't know if
Speaker 5: anybody's looked at the eye movements of octopuses. I think
Speaker 5: probably they have, and they probably do move as I recall,
Speaker 5: But any case, what they do, one of the ways
Speaker 5: you can tell they're in rem sleep is that they
Speaker 5: flash their colors, so their camouflage gets flashy, like, for example,
Speaker 5: a dog twitching its pause.
Speaker 3: That sounds like science fiction. That's crazy, Yeah, I.
Speaker 5: Know it is crazy. So they have a sleeping position too.
Speaker 5: They don't like to sleep except if they're safe, like
Speaker 5: crawled into a hole in a rock or something like that,
Speaker 5: because they also are prey for other sea animals, so
Speaker 5: they try and get to a safe place and a
Speaker 5: place where when they're flashing they can't be seen.
Speaker 2: Yeah, i'd want to hide that color party, yeah, for
Speaker 2: sure from predators.
Speaker 5: Yeah, exactly.
Speaker 3: So this has been a fascinating tour of sleep across
Speaker 3: the animal kingdom and the fungal kingdom and all sorts
Speaker 3: of crazy stuff. But it sounds to me like the
Speaker 3: fundamental answer is that we don't really know what sleep is.
Speaker 3: Is we have this thing in humans we call sleep,
Speaker 3: and we can find correlated activities and other creatures that
Speaker 3: are not the same because they have different brains and
Speaker 3: different bodies, but we still call them sleep. What is
Speaker 3: the thing we can say unifies sleep across all of
Speaker 3: these folks. How do we know we're not just projecting
Speaker 3: our human experience onto mushrooms and black widows?
Speaker 5: Right? Well, I think the less responsive to the environment.
Speaker 5: You're not reproducing, you're not ingesting food. Actually in ungulates,
Speaker 5: let's go back to ungulates for a second. I think
Speaker 5: that was studied in I think it was camels ruminants,
Speaker 5: not ungulates ruminants. So they were thought to sleep a
Speaker 5: lot less because they're actively chewing a lot. But in
Speaker 5: fact they can chew while they're asleep. So it is
Speaker 5: a really good question.
Speaker 2: WHOA, I'm lucky I can't chew while I'm asleep. I
Speaker 2: know i'd get myself in trouble. I do love food.
Speaker 5: Yeah, well it's kind of like tea grinding, I guess
Speaker 5: in humans, but you know they have something to chew
Speaker 5: on their cud. So that's a really good question. And
Speaker 5: I think that it's still controversial, Daniel, because if you
Speaker 5: define it behaviorally, you would say someone who's sleepwalking isn't
Speaker 5: sleeping because they're walking. But in fact we know because
Speaker 5: we can measure eeg that they are asleep while they're sleepwalking.
Speaker 5: So it is tricky. But we do also know that
Speaker 5: the brain at least is doing something wildly different, wildly
Speaker 5: different than when we're awake. We are not processing the
Speaker 5: outside world in the slow wave state of sleep, which
Speaker 5: is one of the two states. Our brain activity electrically
Speaker 5: is periodically active and inactive, and the frequency is about
Speaker 5: one hurts. So we have this blip of activity and
Speaker 5: then a lot of silence, and this silence is something
Speaker 5: you never see during wakefulness, and then a little blip
Speaker 5: of activity and then a lot of silence, And so
Speaker 5: consciousness is probably completely severed during those periods of time
Speaker 5: when the brain is completely inactive, and those little blips
Speaker 5: of activity one hundred milliseconds long or so are probably
Speaker 5: too short to be called consciousness and certainly too short
Speaker 5: to write memories into any long term stores. So that's
Speaker 5: probably why we consider ourselves unconscious. During rem sleep, it's
Speaker 5: an entirely different state. The brain is super active, but
Speaker 5: that activity is all internally focused, so not focused on
Speaker 5: what the outside world is, but this inside reality. And
Speaker 5: that's probably the case of octopuses when they're flashing their camouflage.
Speaker 3: All right, So that's been a fascinating discussion of meditative
Speaker 3: mushrooms and napping black widows. When we get back, let's
Speaker 3: talk more about what's happening while we sleep and what
Speaker 3: it means to dream.
Speaker 2: All right, So I remember hearing that something like dolphins
Speaker 2: and birds sleep with half of their brain at a time,
Speaker 2: which sounds great because then you can be awake. But anyway,
Speaker 2: so my question is is that actually happening, and what
Speaker 2: does that look like and what are the like bonuses
Speaker 2: or drawbacks of that technique.
Speaker 5: Right, Well, if you're a dolphin, the bonuses that you
Speaker 5: can continue to breathe all night long while you're sleeping solid,
Speaker 5: so the half of your brain that's awake keeps the
Speaker 5: dolphins swimming at the surface and able to breathe all
Speaker 5: night long. They switch sides, so one half of the
Speaker 5: brain is sleeping for a while and then the other
Speaker 5: half of the brain sleeps for the rest of the
Speaker 5: time and just switch back and forth. Interestingly that the
Speaker 5: one neurochemical that seems to be changing when the consciousness
Speaker 5: side changes is a seat of coline, which is a
Speaker 5: neurotransmitter that goes all over the brain from one area
Speaker 5: of the brain stem and it's considered to be the
Speaker 5: searchlight of consciousness. So when you're thinking about walking upstairs,
Speaker 5: a seedal coline goes to the motor areas that are
Speaker 5: responsible for your feet walking upstairs, and when you're thinking
Speaker 5: about doing math, A set of coline goes to the
Speaker 5: math areas of your brain and away from the walking upstairs.
Speaker 5: If you're doing walking upstairs and doing math at the
Speaker 5: same time, of course, the seat of colon is in
Speaker 5: both places.
Speaker 2: And you're probably gonna fall fall anyway.
Speaker 5: So for dolphins fur seals that are out hunting for
Speaker 5: long periods of time and not accessing land for several weeks,
Speaker 5: they can also sleep un a hemispherically. Whales sleep, you know, hemispherically.
Speaker 5: And it's true, the side that's a sleep that doesn't
Speaker 5: have these heatal cooline has the big slow waves of unconsciousness,
Speaker 5: and the side that's awake looks like, you know, awake,
Speaker 5: and the eye is open on that side and all
Speaker 5: of that. So actually, so we control our brains. This
Speaker 5: is a little confusing. Our left side of our brain
Speaker 5: controls the right side of our bodies. So if the
Speaker 5: left side of the brain is awake, the right eye
Speaker 5: is open and watching the world around them, and vice versa.
Speaker 5: But so rim sleep rapid I'm of sleep. The one
Speaker 5: that I talked about where you have atonia seems to
Speaker 5: occur only very briefly in these animals that are uni
Speaker 5: hemispherically sleeping, So there's something different about rimsleep that really
Speaker 5: requires atonia, and maybe that's why it's only fifteen seconds
Speaker 5: long in the dolphin. And we haven't recorded the EEG
Speaker 5: the electrodecephalogram from dolphins or whales. It's a little more difficult.
Speaker 5: There's a lot of fat between, you know, to help
Speaker 5: them float between their skin and their brain, and no
Speaker 5: one has attempted it. But we do have another state
Speaker 5: of sleep in whales at least, and I don't know
Speaker 5: if it's been observed in dolphins. It would be interesting
Speaker 5: to see, but where they're not just floating at the
Speaker 5: surface and breathing and sleeping one hemisphere at a time,
Speaker 5: but they're actually below the surface instead of a horizontal position,
Speaker 5: in a vertical position either head down or head up.
Speaker 5: And usually what they do is they start with head
Speaker 5: down and then as the waves and tides move their
Speaker 5: atonic bodies, they eventually sort of go to the head
Speaker 5: up position. It's just they have a lot of fat
Speaker 5: in the head. That's the one that's the more neutral position,
Speaker 5: and they will do that for twenty minutes at a time,
Speaker 5: and that's where their body is completely also atonic, and
Speaker 5: then they swim to the surface and breathe and wake
Speaker 5: up and breathe again.
Speaker 3: But I'm not sure I follow the basic idea of
Speaker 3: why some animals do this and some don't. You said,
Speaker 3: you know, dolphins need to keep swimming and breathing, but
Speaker 3: we also need to keep breathing while we're asleep. Why
Speaker 3: don't we do this as well.
Speaker 5: Right, because well, we can breathe while we're asleep without
Speaker 5: having to swim, you know, we just you know. So, Also,
Speaker 5: dolphins in Wales breathe voluntarily, so it actually requires a
Speaker 5: voluntary sort of waking brain to breathe, whereas we breathe
Speaker 5: involuntarily when we go unconscious. If we were holding our
Speaker 5: breath before we went unconscious, we will start breathing again.
Speaker 3: And whales and dolphins have ancestors that were land animals, right,
Speaker 3: which probably slept more like us. How do you think
Speaker 3: that evolution happened? How do you evolve this kind of thing?
Speaker 5: Right? I don't know. It's incredible, you know the differences
Speaker 5: between species. It's really a beautiful and amazing thing.
Speaker 2: So you mentioned that seals when they go off on
Speaker 2: long foraging trips can do uni hemispheric sleep? Do they
Speaker 2: alternate between un a hemispheric sleep and then everything? Yeah,
Speaker 2: like the whole brain going, oh wow, they can do both.
Speaker 5: Yeah, when they're on what land they do by you know,
Speaker 5: whole brain sleep.
Speaker 1: Wow.
Speaker 5: Yeah. And there's an elephant seal that isn't found to
Speaker 5: do in a hemispheric sleep, either on land or at sea,
Speaker 5: And so that was used to argue that maybe sleep
Speaker 5: isn't necessary because they would be out there foraging for
Speaker 5: a couple of weeks and they're not sleeping for those
Speaker 5: couple of weeks, and then they go back to land
Speaker 5: and they don't have homeostatic rebound like they had been
Speaker 5: sleep deprived for a couple of weeks. So it was
Speaker 5: thought that maybe these are animals that don't need to sleep,
Speaker 5: and maybe sleep isn't necessary or at least not always
Speaker 5: homeistatically regulated. But a few years ago someone at EC
Speaker 5: Santa Cruz outfitted these elephant seals with head caps so
Speaker 5: they could record from their brains while they're out there swimming,
Speaker 5: and they found that in fact, these head caps also
Speaker 5: had GPS. They found that they actually do sleep while
Speaker 5: they're out there foraging, and what they do is they
Speaker 5: take a deep breath, you know, lots of deep breath.
Speaker 5: They swim down, down, down to a depth beneath where
Speaker 5: sharks and killer whales would predate them and where if
Speaker 5: they fall asleep, and when they fall asleep, they start
Speaker 5: sinking instead of floating back up. And so what they
Speaker 5: do is they go into slow wave sleep, and they
Speaker 5: have these beautiful slow waves and they're just kind of
Speaker 5: coasting down as they go into slow wave sleep. And
Speaker 5: then when they go into rem sleep with the atonia,
Speaker 5: whatever body position they're in, if it's less than perfectly straight,
Speaker 5: which always is going to be less than perfectly straight,
Speaker 5: they'll start spiraling. You know. The fin that's down will
Speaker 5: make them spiral. So they will spiral down and down
Speaker 5: and down until they hit the ocean floor, or until
Speaker 5: about seven or eight minutes have passed and they start
Speaker 5: the oxygen need starts giving, making them decide that they
Speaker 5: need to wake up. And so they wake up and
Speaker 5: start swimming up to the surface. And they even while
Speaker 5: they're swim into the surface, they can hold their breath
Speaker 5: for all long time. So even when they're swimming to
Speaker 5: the surface, they could have little naps and then swim
Speaker 5: some more and yeah, it's super cool. So really, sleep
Speaker 5: has been found in every animal, and in every animal
Speaker 5: we look closely enough, seems to have these two stages
Speaker 5: of sleep, so both stages, and both stages are independently regulated,
Speaker 5: so both stages seem to be important.
Speaker 2: So wait, when one hemisphere is asleep, I assume that
Speaker 2: they're less good at doing like, they can't have social
Speaker 2: interactions or anything like that. They're just watching out for
Speaker 2: predators and trying to breathe.
Speaker 1: Is that right?
Speaker 5: Yes? Okay, I think so, Oh yeah, we don't see
Speaker 5: social behaviors which would take the whole body. I suppose
Speaker 5: they could flat one fin waving hey guys, taking a nap.
Speaker 3: Okay, And it makes sense to me that predators might
Speaker 3: sleep like they eat very calorie rich food, they don't
Speaker 3: need to move around their conserving energy. But pray. It
Speaker 3: seems to be like a huge disadvantage to ever go
Speaker 3: to sleep.
Speaker 5: That's right.
Speaker 3: Does that mean that it must be fundamentally important that
Speaker 3: you can't escape at this no evolutionary path away from it.
Speaker 5: I think that's what it means. Yes, So I would
Speaker 5: love to see sleep in the pond organism that can
Speaker 5: survive in space and radiation tartar grade tartar grades. I
Speaker 5: would love somebody to do with sleep in tartar grade
Speaker 5: study because because they survive so well despite all of
Speaker 5: these different assaults on them, they can they have amazing
Speaker 5: abilities to rebuild broken double stranded breaks in their DNA,
Speaker 5: which seems to be also one of the functions for
Speaker 5: sleep is to rebuild a double standard breaks in our DNA.
Speaker 5: So another animal that seems to be really good at
Speaker 5: repairing their DNA is the naked mole rat, which are
Speaker 5: really ugly or cute whatever you think.
Speaker 3: It's a personality test. Actually what the you like the
Speaker 3: naked mole rat?
Speaker 5: It is. So there are some studies done in San
Speaker 5: Diego and then some more studies done in Russia that
Speaker 5: of sleep in the naked mole rat, and they seem
Speaker 5: to sleep so much more than the rest of us.
Speaker 5: And the naked mole rat. And like other rats which
Speaker 5: live about two years, the naked mole rat can live
Speaker 5: thirty five years and when they die it's usually from
Speaker 5: accidents or injuries or something like that. So why do
Speaker 5: they live so much longer? Well, they have this superior
Speaker 5: ability to repair their double stranded breaks in DNA and
Speaker 5: their rim sleep is about fifty percent of their sleep,
Speaker 5: which as for us, it's about twenty five percent on
Speaker 5: a good day. For rats and mice it's more like
Speaker 5: twelve fifteen percent, but with naked mole rats it's fifty percent.
Speaker 5: And that's as much RAM sleep as we get as babies.
Speaker 5: So when we are, you know, learning so much from
Speaker 5: our environment. And actually I want to give you another factoid,
Speaker 5: which is learning requires double stranded breaks in our DNA,
Speaker 5: So every time we learn, we're breaking our DNA in
Speaker 5: order to do that. So, yes, I know why, I've
Speaker 5: never heard that before. Yeah, I don't know why. I
Speaker 5: don't know why. But sleep helps repair repair that and
Speaker 5: so so what are naked mole rats doing there? Babies
Speaker 5: are learning, of course a ton, right and there they
Speaker 5: have about fifty percent when they're born. So why are
Speaker 5: naked mole rats having so much rem all through their lives?
Speaker 5: Are they learning a lot? And there's also seem to
Speaker 5: be any evidence that they're so much smarter than anybody else.
Speaker 3: They're writing the great American novel.
Speaker 5: Of course, baby writing the American novel, but the only
Speaker 5: they can read.
Speaker 3: So you have a lot of questions about sleep and
Speaker 3: all these creatures any humans. Tell us a little bit
Speaker 3: about how we've learned these things, like experiments have you done?
Speaker 3: How do we know these things? Yeah, other than torturing jellyfish?
Speaker 5: Right, watching, right, watching? Just anybody can be a scientist,
Speaker 5: as you know, you just need to. You need to
Speaker 5: observe the world around you, ask questions and try and
Speaker 5: answer them by perturbing that that universe and seeing what happens.
Speaker 5: So we knowie, sleep is homiostatically regulated, even in ourselves
Speaker 5: because when we get less of it one night, we
Speaker 5: are sleepier the next day our drive to sleep is higher.
Speaker 5: But yes, there have been some key experiments throughout history.
Speaker 5: For example, the discovery of rapid I movement sleep was
Speaker 5: probably not the discovery of rapid I sleep at Rapit
Speaker 5: the first report of rappidive I haven't sleep that other
Speaker 5: people could read, and that was an observation made by
Speaker 5: at the University of Chicago by a research scientist who
Speaker 5: is actually the trainee of another research who was studying sleep. Yes,
Speaker 5: had EEG electrodes on people's brains, and this trainee said, hey,
Speaker 5: there seems to be this second state where eyes are
Speaker 5: moving and there's a bit of twitching and respiration changes,
Speaker 5: and the principal investigator the PI didn't believe it, you know, like, yeah,
Speaker 5: it's just a little bit of wakefulness or something else.
Speaker 5: Sleep is just one thing, and it's a we thought
Speaker 5: at that time it was a disconnect from the world
Speaker 5: and it was saving energy, which doesn't appear to be
Speaker 5: very true. Actually. So this trainee hooked up the sun
Speaker 5: of the PI and all night long. And this was
Speaker 5: a young kid, I think ten years old or younger,
Speaker 5: who has more rem sleep and is very thoroughly asleep.
Speaker 5: Kids for it's hard to disturb them. It's hard to
Speaker 5: wake them up out of sleep. Yeah, And so showed
Speaker 5: the record to the PA, this is your son. Look
Speaker 5: at these states, and the p I said, wait a minute,
Speaker 5: and Edison's sleep another night and watched them and you know,
Speaker 5: tried to poke them awake during their rem sleep. When
Speaker 5: he thought that one must have been a wakefulness, the
Speaker 5: sun was quite quite heavily asleep, and realized that, okay,
Speaker 5: there may be you know, maybe there's something to this,
Speaker 5: maybe there's a second state of sleep. So it's kind
Speaker 5: of you know, observations like this, someone saying, hey, this
Speaker 5: is weird. This doesn't follow my hypothesis is what I
Speaker 5: thought would happen, you know, and then pursuing that thing
Speaker 5: that's weird to its end to see what the answers
Speaker 5: are for humans.
Speaker 3: You're obviously limited in the experiments you can do. I
Speaker 3: want to ask you a weird question. Imagine that we're
Speaker 3: not limited.
Speaker 1: I think that's the only kind of question you asked me.
Speaker 3: I know this one's going to feel a little extra weird.
Speaker 3: Imagine you weren't limited by any ethical concerns and you
Speaker 3: only had scientific questions. What experiments would you do to
Speaker 3: learn more about sleep? You know, slicing brains open, torturing people,
Speaker 3: sticking things inside them. I don't know. What would you
Speaker 3: do just from a scientific point of view to learn
Speaker 3: about sleep? What experiments do you wish you could do?
Speaker 5: Yeah, I mean, if it weren't for the dangers involved,
Speaker 5: I would put electrodes in my own brain, a ton
Speaker 5: of them. I would put a thousand of them in
Speaker 5: my own brain. Because one of the things that we
Speaker 5: have discovered from people with electrodes in their brain, and
Speaker 5: they put electrodes in their brain because they want to
Speaker 5: find out where epilepsy is starting. So that they can
Speaker 5: go in and just take out that little section of
Speaker 5: brain which is generating epilepsy all over the brain. So
Speaker 5: when we have looked at twelve of those people who
Speaker 5: had electrodes already implanted in their brain, and we find that,
Speaker 5: in fact, sleep isn't a whole brain phenomenon one third
Speaker 5: of the time. For example, your hippocampus, which is involved
Speaker 5: in recording memories in the first place and then consolidating
Speaker 5: those memories to other parts of the brain. Here hip
Speaker 5: campus can be an entirely different sleep state than the
Speaker 5: cortex is, and it's about a third of the night
Speaker 5: that it's in an entirely different state. So, for example,
Speaker 5: you hip the campus can go into rapid eye movement
Speaker 5: sleep faster and better and longer than the cortext does.
Speaker 5: It can go to sleep actually the first place, sooner
Speaker 5: than the rest of the cortext does. So you could
Speaker 5: be in bed reading a book and about two minutes
Speaker 5: on average before you're actually fall asleep and the book
Speaker 5: hits your face or whatever it is, your hippa campus
Speaker 5: is already asleep. It's not going to remember those that
Speaker 5: last page that you read. You can also tell when
Speaker 5: you're falling asleep, you have to reread the same patches
Speaker 5: again and again. What was that? I don't know, you know, ugh,
Speaker 5: what was that? And that's called sleep onset amnesia. And
Speaker 5: we found in people that your hipp a campus can
Speaker 5: be asleep for twenty whole minutes before the rest of
Speaker 5: your rain is asleep. So don't have a critical conversation
Speaker 5: with your bed partner while they're trying to fall asleep,
Speaker 5: because it's possible they will not remember the conversation the
Speaker 5: next day at all.
Speaker 3: Oh my gosh, you have just inserted yourself in my marriage.
Speaker 3: I have a no important conversation after ten pm rule.
Speaker 3: There you go, which is controversial in my marriage.
Speaker 1: It seems reasonable.
Speaker 2: I'm almost always asleep by ten pm, so ZECH would
Speaker 2: not make much progress anyway.
Speaker 3: But now I have a scientific foundation for winning.
Speaker 5: You do you do?
Speaker 3: Thank you, Gina?
Speaker 4: Yes?
Speaker 1: And well science.
Speaker 5: Yes.
Speaker 2: All right, Let's hope we help some other marriages as well.
Speaker 2: And when we come back, we will talk about dreams. Okay,
Speaker 2: we're back and we are finally going to answer are
Speaker 2: our listeners questions about dreams?
Speaker 1: So Gin know, when do we dream? And why do
Speaker 1: we dream? Tell us about dreams?
Speaker 5: It's a great question, and we can only study dreams
Speaker 5: in people because we can only ask people about their dreams.
Speaker 5: It's a hard one because you can only ask people
Speaker 5: about their dreams when they're awake, so it's kind of
Speaker 5: a retrospective study rather than a live study. However, we
Speaker 5: do dream most when we're in rapid I'm at sleep,
Speaker 5: when our bodies are actively inhibited from acting out those dreams.
Speaker 5: So that's a good thing.
Speaker 3: But how do you know that if you can only
Speaker 3: ask people about their dreams later.
Speaker 5: Yeah, you just wake them up out of different stages
Speaker 5: of sleep, and when you wake them up out of
Speaker 5: round sleep, they're most likely to report having had a dream,
Speaker 5: and the dream is most likely to be the most
Speaker 5: bizarre and lengthy. So if you wake them up out
Speaker 5: of stage two sleep, which is not the deep slow
Speaker 5: wave unconscious state, but rather the first state you go
Speaker 5: into when you're sleep, and then the state that you
Speaker 5: go into right before rem sleep, so it's called a
Speaker 5: transition to rem there are more dreams, but they are
Speaker 5: usually very very brief, also bizarre, but they're not long stories.
Speaker 5: Usually they're just short, little snippets. So when we wake
Speaker 5: people up out of deep slowly sleep, which is hard
Speaker 5: to do because there's a lot of sleep inertia. And
Speaker 5: you ask someone what they were dreaming, they'll say, I
Speaker 5: have no idea, I wasn't dreaming anything. Let me go
Speaker 5: back to sleep, you know, grunt and turnover. Right. It
Speaker 5: doesn't mean that definitively people aren't dreaming as slowly sleep.
Speaker 5: It might just be that they are not remembering it
Speaker 5: when we wake them up.
Speaker 3: But do you have any way to know that their reactions,
Speaker 3: or their stories, or their retelling of their dreams correlated
Speaker 3: at all to their real dreams.
Speaker 5: Yeah, so there is some evidence, but it's controversial, or
Speaker 5: it has been controversial, because there was this idea of
Speaker 5: activation synthesis, so that in fact, you just have little
Speaker 5: blips of randomness when you're an in ram sleep and
Speaker 5: then when you're awake. Because we don't like little blips
Speaker 5: of randomness, we sew them into a story. And that
Speaker 5: dream isn't actually a story, but we've sewn them into
Speaker 5: a story. And there's some a little bit of evidence
Speaker 5: for that. For example, if you have an alarm waking
Speaker 5: you up, you will have a dream that can incorporate
Speaker 5: that alarm. Not everybody does, but you can have a
Speaker 5: dream that incorporates that alarm that starts before the alarm
Speaker 5: started ringing. Like, for example, in your dream, your alarm
Speaker 5: is a ticking bomb and you have to diffuse it.
Speaker 5: But in your dream, you're coming up up on the
Speaker 5: bomb and then you start hearing the ticking And so
Speaker 5: is it that you've retroactively dreamt about the silence before
Speaker 5: the alarm starts ringing in order to make this a
Speaker 5: story or is it that you know We don't know
Speaker 5: the answer to that. But interestingly, because we can put
Speaker 5: electrodes in the brains of rats, actually I want to
Speaker 5: tell you that it doesn't hurt to have an electrode
Speaker 5: in your brain. With these people with electrodes in their
Speaker 5: brain for epilepsy will not report any having any pain.
Speaker 5: Lead actually, strangely, don't have sensory structures in our brain
Speaker 5: to sense what's there. So rats with electrodes in the
Speaker 5: brain will not know that they've got electrodes in their brain,
Speaker 5: and they will sleep wonderfully. They will sleep beautifully, and
Speaker 5: you can see because you can control what happens to
Speaker 5: a rat during the days. You know, rats exploring a
Speaker 5: maze during the day and they're finding food in your maize.
Speaker 5: They will re dream about that maze. They will reactivate
Speaker 5: the same neurons that are active in a particular order
Speaker 5: during the day will reactivate in that order during their
Speaker 5: dream state of rapid eye movements sleep. And you'd say,
Speaker 5: why would they dream about the same thing that they
Speaker 5: were doing during the day. Well, they have a pretty
Speaker 5: boring life except for that exciting running time, and so
Speaker 5: they're much more likely to activate that particular dream. But
Speaker 5: there are a lot of times in rem sleep where
Speaker 5: they're not activating that daze. And so what are they
Speaker 5: dreaming about? We don't know. We would have to record
Speaker 5: every minute of their lives in order to see what
Speaker 5: they're reactivating and what they're dreaming about. But we do
Speaker 5: know that they do reactivate the maze, and interestingly, they
Speaker 5: can reactivate the maze in the same order in which
Speaker 5: they ran at during the day. But they can also
Speaker 5: do bizarre things that they can't do during the day,
Speaker 5: like leap from one side to the maze to the next,
Speaker 5: like we can in our dreams. We can change scenes, right,
Speaker 5: we can. You know, suddenly we're in a boat, you know,
Speaker 5: versus before we were in a house. So and rats
Speaker 5: can do the same thing. So we can't ask them
Speaker 5: about their dreams, but we can see their brain activity
Speaker 5: reactivating this reality that they were in the day before. Also,
Speaker 5: we have this tiny little brainstem area that inhibits our
Speaker 5: muscles when we're dreaming so that we don't act them out.
Speaker 5: When that tiny area of the brain stem degenerates, we
Speaker 5: act out our dreams. That's called RAM behavior disorder, and
Speaker 5: people with that have to actually tie themselves down while
Speaker 5: they sleep so they don't you know, hurt themselves because
Speaker 5: you're completely insensitive to the world around you. You are
Speaker 5: totally in your dream world and you could you know,
Speaker 5: fall downstairs, or walk through a plate growth glass window,
Speaker 5: or beat your bed partner because you're dreaming about, you know,
Speaker 5: an alligator over the side of your canoe. So you
Speaker 5: can also lesion that tiny little area of the brain
Speaker 5: stem in a rat and see the rat act out
Speaker 5: their dreams as well. So they will be you know,
Speaker 5: cowering as though they're dreaming they're being predated upon there's
Speaker 5: somebody spraying on them. They can fight, they can walk around,
Speaker 5: they can you know, phantom eat if it's a I've
Speaker 5: seen the cats do it. They can you know, swat
Speaker 5: at imaginary butterflies and also pounce on the imaginary prey.
Speaker 5: So yeah, this is some evidence that all animals seem
Speaker 5: to dream, including cephalopods which have this flashing of their
Speaker 5: camouflage while they're in that state.
Speaker 2: So we think that's a dream where their body is
Speaker 2: physically responding as opposed to that's just okay, huh.
Speaker 5: Yeah. So what is the origin of dreams? We don't know.
Speaker 5: But there is another part of the brain stem that
Speaker 5: only is active during rem sleep, so during this dream state,
Speaker 5: and it's filled with big excitatory neurons that project all
Speaker 5: over the brain, and it starts firing when we are
Speaker 5: in that end to stage of sleep, which is the
Speaker 5: state when if you wake someone up, they'll report little
Speaker 5: short dreams but not long ones, and then it fires
Speaker 5: like crazy when we're in ramsleep, and it might be
Speaker 5: the origin of the internal origin of dreams. It's right
Speaker 5: beneath an area of the brain brainstem called the locus
Speaker 5: th realist, which gets all sensory information from the outside world,
Speaker 5: and that is actively inhibited when we are in remsleep.
Speaker 5: But just beneath that is this area that comes on
Speaker 5: and comes alive when we're in dream state. So it
Speaker 5: might be the way we feel things and hear things
Speaker 5: and start speaking and all of that. Because this suberlist
Speaker 5: area it's called subserulists projects all over our cortex and
Speaker 5: we don't know because we haven't been able to control
Speaker 5: which areas are active and which are not active in
Speaker 5: the subscuos. To try and control and formulate a dream,
Speaker 5: like an inception of a dream, we can't do that yet,
Speaker 5: but maybe someday we will be able to do that.
Speaker 1: Wow.
Speaker 2: So there are a lot of people who are interested
Speaker 2: in interpreting dreams and trying to decide like what they mean,
Speaker 2: is there any hidden meanings in dreams or is it
Speaker 2: what's the science there?
Speaker 5: Again, that's really difficult because again you can only study
Speaker 5: in waking people. But there is a reactivation of memories.
Speaker 5: If you deprive someone a person of rem sleep, you
Speaker 5: will get a much more pedantic mindset. You can't deprive
Speaker 5: the people of remsleep for very long. That's again independently
Speaker 5: regulated and if given any nap opportunity. Normally, rem sleep
Speaker 5: comes after about ninety minutes or eighty minutes of sleep.
Speaker 5: It's it follows slow wave sleep because your brain needs
Speaker 5: to be in the perfect state temperature wise, et cetera,
Speaker 5: in order to go into this dream state of sleep.
Speaker 5: But if you deprive someone of particularly that dream state
Speaker 5: of sleep, they will go into rem sleep earlier and
Speaker 5: earlier because and get more, They'll get more and more
Speaker 5: of it, and then in fact, just at sleep on
Speaker 5: set they can go into rem sleep. There does seem
Speaker 5: to be a lot of anecdotal evidence that that dreams
Speaker 5: do relate to things that we're experiencing, and for some
Speaker 5: people more than others. A lot of people don't remember
Speaker 5: their dreams at all, so they're not the ones to
Speaker 5: study for this, but those who can remember their dreams
Speaker 5: sometimes it. In fact, dreams do seem to relate to
Speaker 5: the things that you've learned during the day or the
Speaker 5: week before, the month before, and the bizarreness of dreams
Speaker 5: seems to allow us to put things together. So we
Speaker 5: wake up with an aha moment, not always, but sometimes
Speaker 5: with an Aha moment where we've put things together that
Speaker 5: we couldn't you know, our conscious brain just couldn't let
Speaker 5: us put together. So the study of dreams and creativity
Speaker 5: does show that people, for example, doing a task that
Speaker 5: requires a creative insight in order to do it quickly.
Speaker 5: About a third of the people doing this task get
Speaker 5: the creative insight while they're awake and doing the task
Speaker 5: in the first place. Two thirds of people don't see
Speaker 5: the hidden rule that allows them to take the shortcut,
Speaker 5: and of those, half of them through sleep wake up
Speaker 5: and then can do the creative leap, and then a
Speaker 5: one third seem to never get it so unfortunately, and
Speaker 5: those that make that creative leap seem to have a
Speaker 5: lot more activity in this area of the brain that
Speaker 5: causes sleep spindles, which is related to these subsrulist area
Speaker 5: which causes these this activation, this random activation during dreams.
Speaker 3: Are you saying that people have this idea solve a
Speaker 3: problem while they're asleep, and then they wake up and
Speaker 3: they have the solution, or that the sleep is somehow
Speaker 3: prepared their brain to be able to solve this problem.
Speaker 5: It seems like they wake up with the solution so
Speaker 5: that the first time that they're doing it, you know
Speaker 5: they they've got it.
Speaker 3: So it is possible to dream up the great American novel.
Speaker 5: Yes, I think so, all right. There's one famous songwriter
Speaker 5: who said that when he wakes up. If he doesn't
Speaker 5: write down the song that he was dreaming about, God
Speaker 5: will give it to Bob Dylan.
Speaker 1: That's excellent.
Speaker 3: So what do we know about the cultural dependence of
Speaker 3: sleep and dreams? Do people sleep the same way around
Speaker 3: the world, Do they dream the same way? Do we
Speaker 3: have the same relationship with dreams around the world.
Speaker 5: There are cultures that have strong beliefs that these insights
Speaker 5: that come through dreams come from ancestors. That are you
Speaker 5: go to visit your ancestors and your dreams and they
Speaker 5: give you wisdom. Again, there's no scientific evidence, but there are,
Speaker 5: you know, cultural norms surrounding dreams that are different in
Speaker 5: different cultures. There's also cultural norms surrounding sleep in general
Speaker 5: that differ between different cultures. Some cultures don't value sleep
Speaker 5: at all. It's for the lazy, they believe, and there's
Speaker 5: nothing good happening except just turning off your brain and resting,
Speaker 5: and if you're tough, you can do without it. Other
Speaker 5: cultures have a much more an open or receptive view
Speaker 5: of sleep, and sleep is something they welcome each night
Speaker 5: and you with open arms, because that's a time when
Speaker 5: you know, lots of things happened, like consulting with your
Speaker 5: ancestors or whatever it is. There's a really cool study
Speaker 5: in South America by a researcher who's actually at University
Speaker 5: of Washington in Seattle. He put sleep trackers on people
Speaker 5: in a village without any electricity in South America in
Speaker 5: the Amazon, and another set of sleep trackers on people
Speaker 5: with bare minimum electricity like a single light bulb and
Speaker 5: a ceiling, and then on people living in the city.
Speaker 5: And he found that all of these cultures, no matter
Speaker 5: where they were living, sleep less during the full moon
Speaker 5: or the new moon. So he was tracking them for
Speaker 5: a full month and there's a statistical significant difference where
Speaker 5: people sleep less either the full moon or the new moon.
Speaker 5: And so you think it's not light because the new
Speaker 5: moon there's no you know, there's no moon and the
Speaker 5: only light you see the stars when you're out in
Speaker 5: the Amazon, if that at all, So it can't be
Speaker 5: light disturbance. And in fact the people in the city
Speaker 5: also these are college students, they typically spend very little
Speaker 5: time looking at the moon or thinking about the moon,
Speaker 5: so's it seems to be the only explanation that they
Speaker 5: could come up with in his paper is that the
Speaker 5: gravitational pull is stronger on the Earth during both a
Speaker 5: new moon and a full moon, and so maybe there's
Speaker 5: something have to do with gravity and sleepiness.
Speaker 3: Maybe that explains why we sleep worse at high altitudes.
Speaker 3: I always thought that was the oxygen.
Speaker 5: Yeah, No, the oxygen definitely does disturb a sleep. Yeah, yeah,
Speaker 5: I don't know what.
Speaker 3: About people who have different sensations of the world. Dreams
Speaker 3: play a different role in folks who have always been blind, Yeah,
Speaker 3: always been deaf. Can people see in their dreams if
Speaker 3: they're blind.
Speaker 5: No, they do if they're not blind from birth, but
Speaker 5: if they're blind from birth, so no, it's different sensations
Speaker 5: that are that are activated in dreams.
Speaker 1: Daniel, do you want to ask your alien question?
Speaker 5: Oh?
Speaker 3: No, right, So we've asked you about whether sleep is
Speaker 3: something that's common across Earth creatures. How common do you
Speaker 3: think it is across the universe? When aliens come and visit,
Speaker 3: are they going to need to take naps in between
Speaker 3: our conversations or do you think this is something that
Speaker 3: happens only on Earth?
Speaker 5: Well, it does happen on Earth. But whether or aliens
Speaker 5: sleep is a good question depends on what Whether aliens
Speaker 5: need to repair dumble stranded DNA. Do they have double
Speaker 5: stranded DNA. It depends on whether their energy stores works
Speaker 5: the same way. That's a great question because there are
Speaker 5: people who would like to do away with sleep altogether.
Speaker 5: They think the foo ones who think it's a waste
Speaker 5: of time, or who would like sleepiness to not affect
Speaker 5: people's performance, for example. But we have not found anything
Speaker 5: on Earth at least that can replace sleep itself, and
Speaker 5: in fact, without sleep, eventually we die, and that eventually
Speaker 5: is about as long as we take to die without
Speaker 5: any food, So it's as essential as food for us.
Speaker 5: So yeah, it's quite possible. There are aliens who don't
Speaker 5: need sleep work differently.
Speaker 3: Well, when the aliens do arrive, I think I hope
Speaker 3: that they're invertebrates so that you can do all sorts
Speaker 3: of terrible experiments on them. Yeah, I understand.
Speaker 5: No, no, no, no, no.
Speaker 2: I think they're coming up with new rules for working
Speaker 2: on like octopus as well, because oh yeah, they're particularly intelligent.
Speaker 1: And yeah, it's more complicated.
Speaker 5: There are already rules for activists. Yeah, absolutely, yeah.
Speaker 2: All right, Well, thank you so much for chatting with
Speaker 2: us about sleep and dreams. This has been fascinating and
Speaker 2: let's go ahead and hear if our listener had questions answered.
Speaker 4: Thanks for doing your podcast on this. It was really interesting,
Speaker 4: Doctor Poe was really interesting. I've never knew that people
Speaker 4: believe they talk to their ancestors in their dreams. I
Speaker 4: found that fascinating. Thanks for everything you do and I'll
Speaker 4: look forward to hearing all your future podcasts. Byebye.
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