[RADIOLAB INTRO]

HANNAH PALIN: I just thought I'd see if I could get the sound of babies sleeping.

JAD ABUMRAD: This is Radiolab. Today's program is about sleep. I don't have to tell you how good sleep is. You do it yourself every night—or you try. And how wonderful when it actually works, when you can close your eyes and forget the day, and just drift off into oblivion like a little baby. But let's suppose that you are a little baby, this little baby, and you grew up to become a scientist, like one of the scientists we'll hear from in this program. And you decide to ask what should be the dumbest question ever: why do we sleep? And not just us.

SCIENTIST: Well, pretty much everything sleeps.

SCIENTIST: As far as we know, all mammals do it. All birds.

SCIENTIST: Bees, locusts, cockroaches, crayfish ...

SCIENTIST: Reptiles, insects.

SCIENTIST: Scorpions.

SCIENTIST: Everything that's been studied has something that looks like sleep.

SCIENTIST: It's a mystery. Most things we sort of know what they are for, and also how they work. But sleep is really in your face. I mean, everybody does it. You do it from the cradle to the grave. You can't help doing it, because if you try to stay awake, you know, at some point it's irrepressible. And we don't know why. That's a shameful state of affairs. How can you be a scientist in the 21st century and not know the answer to that?

ROBERT KRULWICH: There you go. Okay. [laughs]

ROBERT: That's a pretty good way to begin, you know?

JAD: With shame?

ROBERT: Yeah, yeah. Today on Radiolab, we're gonna try to correct this shameful state of affairs when it comes to the subject of sleep.

JAD: We'll talk with people who can help us understand what it's for.

ROBERT: Why we do it.

JAD: And what happens when we don't.

ROBERT: I'm Robert Krulwich.

JAD: I'm Jad Abumrad.

ROBERT: Stay with us.

JAD: For centuries, people thought that sleep was kind of the opposite of being awake.

ROBERT: It's reasonable, one would think.

JAD: Sure. Because during the day, you're doing all these things, you're having all these thoughts and feelings. At night, you just lie there very, very still. In fact, like, sometimes a bomb could go off and you wouldn't wake up.

ROBERT: I can hardly wake up even in a fire. [laughs] I don't know why! No, I'm a really heavy sleeper. I'm a very, very heavy sleeper.

JAD: The point is, if all you've got are your eyes to go on, sleep can seem like being—well ...

ROBERT: Like being off.

JAD: Yeah, like off-ness.

ROBERT: Right.

JAD: Or worse.

CARLOS SCHENCK: Well, both Shakespeare and Cervantes referred to sleep as 'death.'

JAD: That's Dr. Carlos Schenck. He wrote a great book about sleep called Paradox Lost.

CARLOS SCHENCK: We go to bed every night. We die every night, and then we wake up in the morning and we're alive again. And that was the prevailing theory for centuries.

JAD: For Dr. Schenck, the awakening to just how wrong Shakespeare and Cervantes were about sleep came one day while he was sitting in class for med school.

CARLOS SCHENCK: My first year at medical school ...

JAD: This was back in 1972.

CARLOS SCHENCK: ... we had an emeritus professor who actually was a Nobel Prize winner, Dr. Eccles. Sir John Carew Eccles from Australia.

JAD: Here's what happened. This esteemed lecturer walks into class.

ROBERT: Uh-huh.

JAD: Pops a cassette into the tape deck, hits play, and out comes this sound.

CARLOS SCHENCK: Well, the sound was puh puh puh puh puh puh. Or—wait a second, let me get it right. Oh, here we go. [sound of a pen striking a glass]. And multiply this by a hundred.

JAD: This, the professor announced, is the sound of a cat's brain while asleep.

ROBERT: My God!

JAD: Schenck almost fell out of his seat.

CARLOS SCHENCK: This is the brain during sleep? Making these really rapid, high-pitched, multiple sounds. That just blew us away. It wasn't just ...

JAD: Clearly, while that cat was curled up in its little kitty basket, its brain was very, very alive, much more than anyone expected. And this is still a weird revelation. Like, take my cat, Sammy.

JAD: Sammy.

JAD: All right? [cat purring] This is the sound of my cat, Sammy sleeping. To think that while Sammy is sitting on my lap, totally out, there's a circus happening in his brain. What's going on in there? If you can imagine back in the '70s, this was a paradigm shift. People were suddenly like, "Oh my God, if we're gonna figure out anything about sleep, we have to ask the brain."

JOHN LESKU: And this is the room where we do all of our surgeries.

JAD: And luckily, that's easily done—if you're willing to get your hands dirty.

JOHN LESKU: Okay, so the first step is you have to make an incision on top of the animal's head. When you've done that, we drill holes through the animal's skull, and then you insert your electrodes.

JAD: Then you've got ...

JOHN LESKU: And that's simply it.

JAD: ... a little window into their brain. You could see right there on the screen, you could see the brain waves.

ROBERT: Wait a second. Are you out of your mind? Did you just put a hole into a kitten's head?

JAD: No, that wasn't my cat! C'mon!

ROBERT: So what was it we were doing there?

JAD: What you just heard was a mock surgery to an iguana, actually.

ROBERT: [laughs] Even an iguana. I mean, it's not a nice thing to do.

JAD: Look, look, look. The animal was not harmed.

JOHN LESKU: Within 20 minutes of coming out of the anesthetic, the animal is moving around, it's eating, it's climbing and it's basking. It might seem like a rather invasive procedure, but in actuality, it's not too bad at all.

JAD: Yeah. And that, by the way, is John Lesku. He's a graduate student at the Ecology Department ...

JOHN LESKU: At Indiana State University.

JAD: Which is where we are. John gave our reporter, Kara Oehler ...

KARA OEHLER: Testing.

JAD: ... a tour of the lab.

JOHN LESKU: There are big boys here, and they all have nice hats.

JAD: Showed her the iguanas.

KARA: These guys are a little frightening to me. They're pretty huge.

JAD: They're like four feet long, head to tail.

ROBERT: Oh, I didn't know that.

JAD: I mean, they look like baby alligators.

JOHN LESKU: Pick that one up.

JAD: And John measures their brain waves at night to see what happens in their head as they sleep. In a way, it's a continuation of that cat experiment that Dr. Schenck just told us about, except what they're looking for is much more peculiar than could ever happen in a cat—or in us.

ROBERT: What is that?

JAD: Well, let me put it to you as a puzzle, okay?

ROBERT: Mm-hmm.

JAD: Forget iguanas. Dolphins, right? Dolphins.

ROBERT: Yep.

JAD: How is it that a dolphin in the ocean, or even, say, the dolphins that you might find at Six Flags in New Jersey. They have two.

MEGAN TUTERA: Cody is our 10-year-old Atlantic bottlenose dolphin. His buddy Avalon, is 12 years old.

JAD: And that's their trainer, Megan Tutera. Avir Mitra is holding the mic. Anyhow, here's the puzzle—and we asked Megan about this. How is that her two dolphins, Cody and Avalon, can successfully sleep given the inherent challenges of being a dolphin?

ROBERT: I don't—what are the challenges of a dolphin?

JAD: Well, they have significant challenges, my friend. First, they've gotta breathe.

MEGAN TUTERA: They're not—they're conscious breathers. They're not unconscious breathers. So they have to think about breathing.

JAD: Making matters worse, dolphins are not fish, so they have to breathe air. Which means they have to constantly, consciously, come up to the service to breathe air every few minutes. So you can imagine what would happen if they decided to unconscious for a while.

ROBERT: They would drown.

JAD: Right. And yet they do manage to sleep. A lot.

ROBERT: How long?

JAD: Eight hours a day. Like us.

ROBERT: Really?

JAD: Yeah, eight hours.

ROBERT: But how?

JAD: That's the puzzle.

MEGAN TUTERA: What happens is they do what we call logging. It's when they rest on the surface of the water. You know when a log floats down a river, it just floats?

AVIR MITRA: Uh-huh.

MEGAN TUTERA: That's exactly what they look like. And they rest half their brain at a time.

AVIR: Half their brain is asleep?

MEGAN TUTERA: Half their brain is asleep at a time.

JAD: That is nature's solution: to cut the dolphin brain in half.

ROBERT: You mean literally in half?

JAD: Literally in half, so that one half can snooze while the other half keeps the dolphin swimming and surfacing.

ROBERT: Wow!

JAD: Just enough to breathe. From the outside, you can't really tell what's happening. It just looks like the dolphin is sort of awake, but a little out of it.

MEGAN TUTERA: Well, it's almost like the state of when you're falling asleep, but if something happened, you'd wake right up. So they're in that state all the time.

STEVEN LIMA: This little guy can be characterized as groggy.

JAD: That's Steve Lima. He runs one of the labs back in Indiana.

STEVEN LIMA: They're sort of awake and they're sort of asleep, and it's just a way of staying awake enough.

JAD: And again, it's easy to miss, but if you look inside that groggy dolphin's brain at what the brainwaves are doing ...

STEVEN LIMA: It's exquisitely obvious.

JAD: It's clear as day.

STEVEN LIMA: A six year old could figure it out. One half of the brain has these beautiful slow waves like a sine curve, and the other one's just jagging all over the place.

AVIR: Awesome! Oh, those are beautiful!

ROBERT: Wow, that is amazing!

JAD: Yeah, it's called unihemispheric sleep. That's what the guys at Indiana State are really interested in because—and here's the next surprise, it seems to go way beyond dolphins.

JOHN LESKU: Oh yeah. They're aquatic mammals like whales, seals and sea lions.

JAD: John says that all of the marine mammals that have been studied seem to do it too.

JOHN LESKU: Recently walruses, they all are found to engage in unihemispheric sleep as well.

JAD: And now the Indiana team led by this guy ...

CHARLES AMLANER: I'm Charles Amlaner, chair of the Department of Ecology and Organismal Biology.

JAD: ... they have found this weird split-brain behavior in creatures of the air.

ROBERT: Oh!

CHARLES AMLANER: Okay, let me just back up a little bit and describe this experiment.

JAD: Charlie and his student had been at the park one day and they noticed something.

CHARLES AMLANER: We observed that ducks ...

JAD: Ducks.

CHARLES AMLANER: ... sometimes will get together into groups.

JAD: Like, on a log. Four ducks will get together and snooze in a neat little line.

CHARLES AMLANER: And the birds that were sitting in the middle of that line tended to be sleeping with both eyes closed. The birds that were sitting on the outside of that row tended to look a little bit more wary.

JAD: The inevitable question ...

CHARLES AMLANER: What's going on here?

JAD: ... led to a very simple experiment.

CHARLES AMLANER: We put four birds in a row.

JAD: Four mallard ducks, this time in a lab. And they watched them sleep.

CHARLES AMLANER: The two birds in the center of this row slept with both eyes closed. The birds on the outer edges, both left and right, slept with one eye closed and one eye opened.

JAD: One more time.

CHARLES AMLANER: Slept with one eye closed and one eye opened.

JAD: It's just like in that song. You know that Metallica song?

ROBERT: [laughs] I missed it.

JAD: It's a good one.

ROBERT: But I knew they were all botanists.

JAD: It's true! You know, no one knows this, but that song is really about adaptive sleeping behavior in ducks.

CHARLES AMLANER: The outer eye, the eye that was faced away from the group, the eye that was facing towards where potential predators might come from, that stayed open.

JAD: At this point, Charlie had a pretty good idea of what was going on, because he knew that inside bird brains, each eye is attached to the opposite hemisphere.

CHARLES AMLANER: The left eye is attached to the right hemisphere, the right eye is attached to the left hemisphere.

JAD: So his team implanted some electrodes to measure what the duck brains were doing and—voila! Like the dolphins, the ducks too were sleeping one half of their brain at a time.

CHARLES AMLANER: The bird could simultaneously sleep and be awake.

JAD: Not only that—here's the cool part—after a few hours ...

CHARLES AMLANER: What happened was is that the birds that were on the outer edge, then would rotate.

JAD: Stand up, turn around.

CHARLES AMLANER: 180 degrees.

JAD: And then sit back down.

CHARLES AMLANER: And the other eye would then get some sleep, and consequently the opposite hemisphere would get some sleep.

JOHN LESKU: When we saw that we said "Oh yeah, that's good!"

JAD: Good, because right there in the ducks was a perfect illustration of what these guys think it's all about: you gotta sleep, for whatever reason.

ROBERT: Right.

JAD: But sleep is dangerous. That's the headline. For dolphins, the main danger is drowning, you know?

ROBERT: Yeah.

JAD: For ducks ...

ROBERT: Getting eaten.

JAD: Exactly. Ducks have to sleep, but how can they when lurking in the darkness are foxes and wolves and a hundred other eaters of ducks.

JOHN LESKU: Do you like snakes?

KARA: I don't know. Not really.

JOHN LESKU: What?

KARA: I don't dislike snakes.

JOHN LESKU: He's a good man. He's a good man.

KARA: Mm-hmm.

JAD: In another nifty experiment, John took the resident snake, Monty ...

JOHN LESKU: This is Monty.

KARA: Hi.

JAD: Big snake.

JOHN LESKU: He is, what, about a four-foot-long python.

JAD: And at night ...

JOHN LESKU: You're so cute!

KARA: [laughs]

JAD: ... John brought Monty the python into the room where his iguanas sleep.

JOHN LESKU: And he terrifies them.

ROBERT: Really?

JAD: Well I mean, Monty was in a cage, so he couldn't really hurt the iguanas. But as soon as that snake appeared, all the lizards popped one eye open.

ROBERT: [laughs] I bet they did!

JAD: Pop, pop, pop, pop! And they trained that open eye right on Monty the snake.

STEVEN LIMA: Put a big snake in the room, and they'll watch it with one eye all night.

JAD: That's Steve Lima again.

STEVEN LIMA: They don't like these snakes, that's for sure. And I mean, we moved the snake from the room the next day and they're still looking for it the next night or two.

JAD: So they keep one eye trained on that door for a few more days?

STEVEN LIMA: About two or three days, then they go back to regular sleep.

ROBERT: So what does this all mean?

JAD: Well, think about this. Okay, all the sea mammals, they do it.

ROBERT: Right.

JAD: Well, at least the ones that have been studied. All the flying creatures, they do it. The reptiles seem to do it too. Who does that leave?

ROBERT: You mean who's left not sleeping with half a brain on and the other half a brain off?

JAD: Yeah.

ROBERT: Um ...

JAD: Us!

ROBERT: Really?

JAD: We may be the strange ones.

JOHN LESKU: Well, it is sort of strange in that terrestrial mammals can't do it. Terrestrial mammals just for some reason have lost the ability to do this.

JAD: Not all mammals, says John. The terrestrial mammals. The ones that live on land.

ROBERT: Ah.

JAD: And here's his theory: sometime, long ago, our scaly ancestor wandered up on the land and thought, "I think I'll dig a hole. Yeah, I'm gonna dig a hole." And the hole was dark and it was safe, and for the first time in millions of years of evolution, that little creature closed both eyes. Ahh! And so we lost it.

ROBERT: [laughs]

JAD: Totally speculative theory, of course, but the basic idea, though, is if you are protected and safe, you can afford to close both eyes, conk out completely. And that simple idea of safety, that explains—well, these guys think, almost everything: where you sleep, how you sleep, how long you sleep, it all boils down to two words.

STEVEN LIMA: Predation risk.

JOHN LESKU: Predation risk.

CHARLES AMLANER: Predation risk.

JAD: Which is really just a fancy way of saying ...

CHARLES AMLANER: Generally speaking, just your risk of being killed.

JAD: Your risk of being eaten. Now what does this have to do with us? Here we are, top of the food chain, in our warm beds.

CARLOS SCHENCK: Nice warm bed.

JAD: A locked door.

CARLOS SCHENCK: A locked door. Covers.

JAD: Maybe a nice neighborhood.

CARLOS SCHENCK: A good police force looking after you at night time. And you live in a country that has a very secure living environment.

JAD: You would think that this whole predation risk idea has nothing to do with us. Well?

CARLOS SCHENCK: Well, there's a few studies that have looked at, say, sleep patterns where people are sleeping in novel environments.

ROBERT: What's a novel environment? What does he mean?

JAD: Well, like a hotel.

ROBERT: Oh.

JAD: That first night at a hotel, why is it no one can sleep well that first night at a hotel?

CARLOS SCHENCK: On your first night of sleeping in a hotel room, you generally have less REM sleep and less deep, slow wave sleep relative to sleeping in your house.

JAD: I suffer from that myself, I don't sleep well in hotel rooms. Especially if it was just one night per place or something, my sleep is terrible.

CARLOS SCHENCK: There are some folk that actually hypothesize there are certain predator relays in the brain, and that these circuits remain active at all times.

JAD: Now what if that's true that we all have, buried deep in our reptile brain, a sort of predator alert system? Perhaps in some of us, it's a little too sensitive.

CARLOS SCHENCK: Okay we're in the sleep lab at the Minnesota Regional Sleep Disorder Center—Mission Control, we call it. We're viewing the typical sleep terror episode. This little girl who is five years old would engage in these sleep terror episodes every single night.

JAD: That's Dr. Carlos Schenck, who we heard from before. We're in Minnesota now at the Hennepin County Sleep Center ...

CARLOS SCHENCK: Here in the sleep lab ...

JAD: Where he works. We're standing in front of a grainy, black-and-white video of a little girl in her PJs, screaming.

CARLOS SCHENCK: So look at the time.

JAD: Dr. Schenck discovered an odd category of sleep disorders called 'parasomnias,' which is why we came to talk to him. 'Para' means around, 'somnia' means sleep. Around sleep. This might be the human analog to the ducks: people whose brains never quite shut off completely during sleep.

CARLOS SCHENCK: Well, this guy is interesting. He has seizures. No, no, no, he doesn't. Wait a second.

JAD: He showed us tape after tape.

CARLOS SCHENCK: We're viewing a man who we very affectionately call Santa Claus.

JAD: On the screen, a large guy thrashes back and forth.

CARLOS SCHENCK: His legs are moving. He's going back and forth from his side to his back.

JAD: And then suddenly, he starts to ...

[ARCHIVE CLIP: Ho, ho, ho, ho, ho. Ho, ho, ho, ho, ho, ho, ho. Ho, ho, ho.]

ROBERT: Is this real?

JAD: Yeah. This guy is in and out of sleep. He has no idea what he's doing. One of the interesting things Dr. Schenck noticed when he first began to diagnose parasomnias in the early '80s is that while they were in that kind of liminal space around sleep, a huge percentage of the patients would have these visceral dreams of being attacked.

CARLOS SCHENCK: The common theme is a menace is posed from nowhere, coming out of nowhere. It's an immediate threat that you just can't ignore. Let's put it that way. You have to either fight it or run away from it.

MARTIN SABELLE: The dreams can be very violent.

JAD: This is Martin Sabelle, age 88. He's another of Dr. Schenck's patients.

MARTIN SABELLE: I remember someone coming up the stairway.

JAD: In Martin's case, the attackers never had a face. Sometimes it was a bear.

MARTIN SABELLE: And I was gonna fight with him.

GERTRUDE SABELLE: He'd yell at them, "Get out of here!"

JAD: That's Martin's wife, Gertrude.

GERTRUDE SABELLE: "Scram!" He was always trying to protect me.

MARTIN SABELLE: Yeah, I would have black and blue bruises on my arms and hands because I was hitting the headboard.

CARLOS SCHENCK: Not infrequently, the man is dreaming, in bed with his wife, that he is fighting to defend her from an attacker, when in fact, he's beating her up.

GERTRUDE SABELLE: One night I was sleeping, and all of a sudden he's got his hands tightly around my throat. I'm petrified. "Quit, Mart! You're dreaming. You're hurting me."

MARTIN SABELLE: She says, "Martin, you're dreaming."

JAD: Gertrude and Martin Sabelle are still married, believe it or not, after 57 years. Though she did force him to sell his guns.

GERTRUDE SABELLE: He has never been happy about that.

MARTIN SABELLE: Well, they were quite valuable.

ROBERT: So you're suggesting then, that all these people, and the iguanas and the ducks and the dolphins all have a portion of their brain which is wary in the night?

JAD: That's what I'm hinting at. I don't want to go any stronger than hint at, but there seems to be something in us that's always watching out, always wary.

ROBERT: Bottom line here, though, is that sleep for all creatures is a dangerous thing, and a few unfortunate people are still awake to that fact.

JAD: That's right. Before we go to break, I just wanna thank Ann Hepperman for her excellent reporting in Minnesota, and also before her, Kara Oehler. And to remind you to stay with us because we're gonna turn our attention shortly from danger to deprivation. Radiolab will continue in a moment.

 

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