Essentials: Use Sleep to Enhance Learning, Memory & Emotional State | Dr. Gina Poe

0:00Welcome to Huberman Lab Essentials,

0:01[music] where we revisit past episodes

0:04for the most potent and actionable

0:06science-based tools for mental health,

0:08physical health, and performance.

0:11I'm Andrew Huberman and I'm a professor

0:13of neurobiology and opthalmology at

0:15Stanford School of Medicine. And now for

0:17my discussion with Dr. Gina Poe. Dr.

0:20Gino Poe, welcome.

0:21>> Thank you.

0:22>> I've really been looking forward to this

0:24conversation. I know that many people

0:25are going to be excited to learn about

0:27your work as it relates to sleep, as it

0:30relates to problem solving, creativity,

0:32and a number of other important topics.

0:34To start things off, I would love for

0:36you to educate us a bit about this thing

0:38that we are all familiar with and yet

0:40very few of us understand, which is

0:42sleep. Could you describe the various

0:44phases of sleep that exist, what

0:46distinguish them, and perhaps frame this

0:49within the context of what would a

0:51perfect night's sleep look like?

0:53>> All right. So sleep is really different

0:55from wakefulness and in fact can't be

0:57replaced by any state of wakefulness

1:00that we've been able to come up with so

1:01far. Our brain chemistry is completely

1:04different and in the different stages of

1:06sleep which there are is nonREM and REM

1:08are the two major states of sleep. Those

1:10two states are entirely different from

1:12one another too. And even within nonREM

1:14there are three states. Stage one, which

1:17is what you slip into when you first

1:19falling asleep. It's dozing. There's

1:21kind of an interesting rhythm that goes

1:23on in the brain. It's kind of a fast

1:24gamma rhythm. And then there's stage

1:27two, which is a really cool state. We

1:29sort of used to ignore sleep researchers

1:32because it was a transient state between

1:34wakefulness and the deep stage three

1:36slowwave sleep, which is the most

1:37impressively different, which is when

1:39big slow waves sweep through our brain.

1:41And now we've realized that it cleans

1:43our brain. Um, one of the things that

1:45those big slow waves do is cleans our

1:47brain and does other really important

1:48things to restore us from a day of

1:51wakefulness. And then REM sleep, which

1:53is the most popular because that's where

1:55we have the most active dreams. When you

1:57wake up someone out of REM sleep,

1:59they'll almost always report having

2:01dreamed something really bizarre. That's

2:03called REM sleep, rapid eye movement

2:05sleep. So those are the four states of

2:07sleep of human sleep. And we cycle

2:09through them every 90 minutes or so. And

2:12then we start over again. And we have

2:15about five of those per night for a

2:16perfect night's sleep. Four or five,

2:18something like that. So a perfect

2:20night's sleep is 7 and 1 half, 8 hours.

2:23And

2:23>> what about the sleep where we are

2:25lightly asleep

2:27>> and we might have a dream that has us

2:30somehow thinking about movement or that

2:31we jolt ourselves awake. That often

2:33happens early in the night, right?

2:34>> Yeah. That's the first stage, stage one

2:37and stage two of sleep. And stage two

2:39sleep is really cool because that has

2:43something called sleep spindles and K

2:45complexes. And what sleep spindles are

2:47are a little of activity that's 10 to 15

2:51hertz in frequency. It's a conversation

2:54between the phalamus and the cortex. The

2:57phalamus is the gateway to consciousness

2:59and the neoortex, you know, processes

3:01all our cognition. And if you wake up

3:03out of that state, you will often report

3:05a dream like a hallucination style

3:08dream. It won't be a long dream report

3:10like you have out of REM sleep, but it

3:12will be some hallucination state.

3:14>> Are they quite different than the

3:16patterns of sleep and dreaming that

3:18occur later in the night or toward

3:19morning?

3:20>> There is some evidence that the first 4

3:23hours of sleep are very important for

3:26memory processing. And in fact, if

3:28you've learned something new that day or

3:31have experienced a new sensory motor

3:34experience, then your early sleep dreams

3:38will incorporate that experience much

3:40more than the later sleep dreams. Later

3:42as that memory gets consolidated from

3:45the early structures which are the

3:47hippocampus deep in the temporal lobe to

3:49the cortex in a distributed fashion that

3:53memory seems to move from that

3:56hippocampus to the cortex and also the

3:58dreams that incorporate that memory also

4:00move later in the night. So

4:02>> there was a great study by Sedarto Rayo

4:06who studied the consolidation of

4:08memories from the hippocampus to the

4:10cortex in a rat across the period of a

4:13full day sleep because rats sleep in the

4:16daytime. And he found that each

4:18subsequent rim sleep period moved that

4:22memory from the hippocampus to the f

4:25first area that projects to it and then

4:27the second area and then the third area.

4:29and you can see the memory moving um

4:32through the throughout the sleep.

4:34>> There's a number of different hormones

4:36associated with the different stages of

4:38sleep. We know that melatonin is a

4:40hormone

4:41>> of night time

4:41>> of nighttime that makes us sleepy. What

4:44about growth hormone release? When does

4:45that occur during sleep?

4:47>> So growth hormone release happens all

4:48day long and all night long. But the

4:51deep slow wave sleep that you get, the

4:53very first sleep cycle is when you get a

4:56big bolus of growth hormone release. and

4:58in men and women equally. And if you

5:02miss that first deep slow wave sleep

5:04period, you also miss that big bolus of

5:07growth hormone release. And you might

5:09get ultimately across the day just as

5:12much overall growth hormone release. But

5:14andologists will tell you that big

5:16bololises do different things than a

5:19little bit eaked out over time. There's

5:21also a big push to synthesize proteins.

5:24So that's when the protein synthesis

5:27part that builds memories for example in

5:30our brain happens in that first cycle of

5:33sleep. So you don't want to miss that

5:35especially if you've learned something

5:36really big and needs needs more synaptic

5:39space to encode it.

5:40>> How would somebody miss that first 90

5:42minutes

5:43>> depriving themselves? Yeah. So, so let's

5:45say I normally go to sleep at 10:00 p.m.

5:48>> and then from 10 to 11:30 would be this

5:50first phase of sleep and that's when the

5:52growth hormone big bololis of growth

5:54hormone would be released. Does that

5:55mean that if I go to sleep instead at

5:5811:30 or midnight that I miss that first

6:00phase of sleep? Why is it not the case

6:02that I get that first phase of sleep

6:04just simply starting later? Every cell

6:06in our body has a clock and all of those

6:08circadian clocks are synchronized and so

6:11our cells are ready to respond to that

6:15growth hormone release at a particular

6:17time and if we miss it and it's a time

6:19in relation to melatonin also. So if you

6:22miss it, yeah, you might get some growth

6:25hormone release, but it's occurring at a

6:27time when that your clock has already

6:28moved to the next phase. And so it's

6:31it's just a clock thing. So what this

6:33means is that we should have fairly

6:35consistent bedtimes in addition to

6:36fairly consistent wake times. Is that

6:38right?

6:39>> Exactly. And in fact, one of the best

6:41markers of good neurological health when

6:44we get older is consistent bedtimes.

6:47>> What other things inhibit growth hormone

6:49release or other components of this

6:51first stage of sleep? Are there things

6:53that I perhaps do in the preceding hours

6:55or the preceding day like ingest

6:57caffeine or alcohol that can make that

7:00first stage of sleep less effective even

7:02if I'm going to sleep at the same time?

7:03>> Alcohol definitely will do that because

7:05alcohol is a REM sleep suppressant and

7:07it even suppresses some of that stage

7:09two transition to REM with those sleep

7:11spindles. And those sleep spindles, we

7:13didn't talk about their function yet,

7:14but they're really important for moving

7:17memories to our cortex. It's a unique

7:19time when our hippocampus the sort of

7:22like the RAM of our brains writes it to

7:25a hard disk which is the cortex and

7:27there it's a unique time when they're

7:29connected. So if you don't want to miss

7:31that you don't want to miss REM sleep

7:33when is also a part of the consolidation

7:35process and alcohol before we go to

7:37sleep will do that until we've

7:39metabolized alcohol and put it out of

7:41our bodies it will affect our sleep

7:44badly. What about the second and third

7:4790minute blocks of sleep? Is there

7:48anything that makes those um unique?

7:51What what is their signature? Besides

7:53the fact that they come second and third

7:54in the night,

7:55>> there's more and more REM sleep the

7:57later the night we get. There's also a

8:00change in hormones. You know, the growth

8:01hormone and melatonin levels are

8:04starting to decline, but other hormones

8:06are picking up. So, it is a really

8:09different stage that you also don't want

8:11to short change yourself on. And I think

8:14that's the stage many studies are

8:16showing that those are the times in

8:18sleep when the most creativity can

8:20happen. That's when our dreams can

8:22incorporate and put together old and new

8:25things together into a new way and our

8:28schema are built during that time. So

8:31that's when your computer of your brain

8:33is opening folders and comparing

8:35documents seeing if is there anything

8:37the same? Are these two documents look

8:39very much the same? that there's a

8:41little bit of difference and it can it

8:43can link those conceptually. So that

8:45that's probably one of the origins of

8:47creativity is finding things that are

8:49related maybe just linked a little bit

8:52and you can find that link and

8:54strengthen it if it you know makes your

8:57schema interesting and different.

8:59>> Many people including myself tend to

9:01wake up maybe once during the middle of

9:03the night to use the restroom. I've

9:05tried to drink less fluid before going

9:07to sleep. I've heard also the impulse to

9:09urinate is also dictated by how quickly

9:11you drink fluid, not just the total

9:12volume. So, I've switched to um sipping

9:14fluids more slowly for my last beverage

9:16of the day, which seems to help. Is

9:18there any known detriment to this middle

9:21of the night waking or should we

9:23consider it a normal feature for some

9:25people's sleep architecture?

9:26>> Yeah, I think we shouldn't worry about

9:28it. Actually, sleep is really incredibly

9:30well homeostatically regulated. And so

9:33really don't worry about how much you're

9:35sleeping as long as you're not

9:37intentionally depriving yourself of

9:38sleep by doing something really

9:40rewarding and exciting because even that

9:42is stressful to your body and deprivives

9:44you of a lot of the things we're talking

9:45about. It's absolutely normal to wake up

9:48at least once in the middle of the night

9:49to go to the bathroom. And as long as

9:51you can get back to sleep in a

9:53reasonable amount of time or even if it

9:55takes you an hour, don't worry about it.

9:57as long as you have a lifestyle that

9:59allows you to then make up that sleep

10:01either the next morning or the next

10:03night um or going to bed a little

10:05earlier.

10:06>> What is unique perhaps about the

10:08architecture of dreams and sleep in the

10:11let's say the last third of the night or

10:13the or the second half of the night,

10:14>> right? Yeah. In the second half of the

10:15night, we have longer REM sleep periods

10:18and those are considered the deepest

10:21sleep. Even though slowwave sleep, big

10:24slow wave is considered deep. It is

10:26deep.

10:26>> Yeah. They call slowwave sleep deep

10:28sleep and REM sleep rapid eye. But now

10:30you're telling me that REM sleep is

10:31actually the deeper sleep.

10:32>> The reason why you call slowwave sleep

10:34deep sleep is because it's difficult to

10:36arouse people out of that state. And

10:38when you do arouse them out of that

10:40state, they're most often confused and

10:42just want to go back into sleep and can

10:44go back pretty easily. If you arouse

10:47someone out of REM sleep, they're more

10:49likely to report something that was

10:50really kind of almost like wakefulness.

10:52It's it was so vivid. And maybe one of

10:54the reasons why REM sleep is deeper is

10:57especially in adults and older people

10:59that deep slowwave sleep goes away. So

11:02it's not as deep. It's not as big. The

11:04slow waves aren't as large which is

11:06probably problematic but we are not

11:08sure. And so then REM sleep becomes the

11:11deepest stage.

11:12>> We are paralyzed during REM sleep.

11:14Correct.

11:15>> Yes. normally paralyzed and that's

11:16really good because that's the time when

11:19we're actively dreaming storyline dreams

11:22and we could hurt ourselves. We're

11:24actually really cut off from the outside

11:26world in terms of responding to say this

11:30table or window or a door and so

11:33different from sleepwalking which is out

11:35of slow sleep. Out of slow sleep that

11:37sleepwalking is a mixture between sleep

11:39and wakefulness. You can cook a full

11:41meal, um, drive your car while you're in

11:44deep, slow sleep. It's scary because you

11:46never know what you're going to do. You

11:48don't have voluntary voluntary control

11:50over it. You have no conscious control

11:51over it, but you can actually safely

11:54navigate um some situations in

11:57sleepwalking and actually have a

11:59conversation. Although it may not make

12:00much sense when you're sleeptalking, in

12:03REM sleep, you're not processing the

12:06outside world. and instead um when

12:08you're acting out your dreams, you could

12:10be doing things like walking through a

12:12plate glass window or falling off of,

12:15you know, down a stairs um things like

12:17that. So, you really want your muscles

12:20to be inactivated during REM sleep,

12:23otherwise you will act out those dreams

12:25and really hurt yourself or your bed

12:27partner. So, as people start to approach

12:31morning or the time when they normally

12:32would wake up, I've heard that it's

12:34important to, if possible, complete one

12:37of these 90minute cycles prior to waking

12:40up. That is, if you set your alarm for

12:42halfway through one of these 90minute

12:44cycles that come late in the night of

12:46sleep that it can lead to um rather

12:50groggy patterns of waking.

12:52>> It's called sleep inertia. When we wake

12:53up out of the wrong state, I liken it to

12:56a washing machine cycle. This 90 minute

12:58cycle is like a washing machine cycle.

13:00And the first part is to add water,

13:02right? Then your clothes are soaking

13:03wet. You don't want to open the washing

13:05machine and try and function, put them

13:07on and wear them around while they're

13:09soaking wet and full of soap. So you

13:11have to wait until the cycle is through

13:14before you can well actually

13:16put it in the dryer, too. Um before you

13:19want to wear them. So you can function.

13:22It just takes a little while for those

13:24clothes, that brain to dry out so you

13:26can actually function well. But it's

13:28better to wait through the whole cycle

13:30is complete. So that's why you want to

13:33set that 90 90 minute alarm clock. And

13:36again, that's around 90 minutes because

13:39the first stage of sleep, the first

13:41cycle of sleep is actually a little

13:42longer, more like 105, 110 minutes. But

13:46then the second ones and third ones,

13:48they get sort of shorter and shorter as

13:49the night goes on. And in the last few

13:52cycles, you're just doing the N2 REM

13:55sleep cycle, which takes less time. And

13:57if you wake up out of REM sleep, there's

13:59usually no problem cognitively.

14:01>> Are you a fan of of sleep trackers?

14:04>> Yeah.

14:04>> Yeah. Do you use one?

14:05>> I have one on. I don't live my life by

14:08them because the best ones right now are

14:11about 70% effective at

14:13>> staging your sleep. So 70% it's okay.

14:16It's okay. But um take it with a grain

14:18of salt is what I'm saying. tell us a

14:20little bit more about the wash out that

14:22occurs in the brain during sleep and

14:24perhaps if there are any ways to ensure

14:25that it happens or to ensure that it

14:27doesn't happen and obviously we want

14:29this to happen.

14:30>> Yeah, we talked about the circadian

14:31clock and how certain things happen at

14:34certain times. Well, one of the things

14:35that happens when we're awake and

14:37talking to each other is that there's a

14:40lot of plasticity. there's something

14:42that I'm learning from you today and

14:43you're learning from me and that changes

14:46our synapses and it changes the way our

14:48proteins are going to be folded and

14:52changed during sleep. This process

14:54actually uses a lot of ATP, the power um

14:58structure, the fuel of the brain. It

15:00unfolds also proteins while we're doing

15:02this, while we're using them. And so

15:05during that first part of the night, uh,

15:07when we first fall asleep, in the first

15:0820 minutes or so, we're building that

15:11adenosine back into ATP. And that's, uh,

15:14probably why power naps are called power

15:16naps because we're actually rebuilding

15:19the power. And then we're also cleaning

15:23out through the deep slow waves of slow

15:25wave sleep. We're cleaning out all those

15:27misfolded proteins, unfolded proteins,

15:29and other things that get broken down

15:32and, you know, need to be rebuilt when

15:35we're asleep because of its use during

15:38wakefulness. So I liken that to, you

15:41know, having a big party during

15:43wakefulness and you need all those

15:44partygoers to leave in order to do the

15:46cleanup. What happens when a neuron is

15:48firing is that it expands. The membrane

15:52expands a little bit. It becomes more

15:53translucent. That's how we know, one of

15:55the ways we know that neurons expand

15:57when they fire. And so every action

15:59potential, the membrane expands a little

16:02bit as sodium brings water into the

16:04cell. And then when they're silent, they

16:06contract. And so in during slow waves,

16:09the cool thing is that the reason why

16:11you can measure them is that all the

16:12neurons at the same time, not all of

16:14them, but a good portion of them are

16:17firing at the same time and silent at

16:19the same time. And so you think about

16:21that as contracting and expanding all at

16:23the same time. It's kind of like a

16:25billagege pump of the brain. So that can

16:27pump out. GIA are also really important

16:30for this in terms of cleaning up debris

16:33and transferring it to where it needs to

16:35go. So, um, so I think of it actually as

16:38a billagege pump cleaning out our brain.

16:41>> Here you're talking about literally an

16:43expansion and a contraction of the

16:44neurons in unison

16:46>> and pushing the fluid through

16:48>> cleaning out any misfolded proteins or

16:50debris that might occur

16:52>> on the basis of these metabolic

16:53pathways.

16:55>> And the consequence of that is to to

16:57what to leave the brain in a state of

17:00more pristine action for the next day.

17:02Is that right?

17:03>> Yeah. You think of it again like a party

17:05and if you don't clean up after that

17:07party and you try and hold another one

17:08the next day, it's going to get more

17:10clogged. You know, it's people have a

17:12harder time moving around and enjoying

17:14themselves. And um if that builds up day

17:17after day, you know, it's going to be

17:18cognition that would be the partygoers

17:21moving around becomes

17:24hard.

17:25>> And so this um build pump that you

17:27describe is associated with the big slow

17:29waves of slowwave sleep. So this is

17:32going to occur more or less in the first

17:33third of the night. Is that right?

17:35>> That's right.

17:35>> And is this similar to the case with

17:37growth hormone where if you go to sleep

17:39later than you would normally, you miss

17:42the wash out. You It's not You don't

17:44delay it. You miss You miss the wash

17:46out.

17:46>> That's right. That's right. So if you go

17:48to sleep at 1 or 2 in the morning, your

17:50sleep is still going to be dominated by

17:52N2 and REM sleep, not by slow wave

17:55sleep. So you need to you need to get

17:57that first bit of sleep. Would a caveat

18:00to that be if somebody normally goes to

18:02sleep at 1 or 2 a.m. and wakes up at

18:0410:00 a.m. if that's their normal sleep

18:06cycle?

18:06>> Yeah, it should be okay. Somebody would

18:09want to do a sleep study with people who

18:11do that normally and see if also the

18:13melatonin release is later and the

18:15corticostone rise that's happens

18:17normally in the morning also happens

18:19later. So if everything shifted good,

18:23>> I'd love for you to tell us about this

18:25incredible structure in the brain which

18:27is the locus ceruius and hopefully tell

18:30us a little bit about its relationship

18:31to epinephrine aka adrenaline.

18:34>> Yeah. So um the locus curillus is filled

18:37with neurons that have in them

18:39norepinephrine which is the brain's

18:41version of epinephrine or adrenaline.

18:43It's also called noradrenaline. And what

18:46it does is it just like adrenaline in

18:48the rest of our bodies, it helps prime

18:49us to respond to our environment. So

18:53when locus rules neurons fire and fire

18:56in a burst, we can switch our attention

18:59and they will fire in a burst if for

19:01example a loud noise happens in the

19:03middle of your concentrating on

19:04something. It fires and it helps you

19:06switch your attention to that thing and

19:08then learn quickly from it. So it's

19:10really important in a stress response.

19:12It helps us do quick one trial learning.

19:15But just tonic levels are signature of

19:18wakefulness and alertness. So too much

19:21is panic with the locusillis activity. A

19:24burst is switching attention. And then

19:27tonic levels are sustained constant

19:30attention. And then when we go to sleep

19:32the locus slows and come goes from about

19:36on average um two hertz to about one

19:39hertz one cycle per second tonically and

19:42then when we go into REM sleep it's the

19:44only time when it shuts off completely

19:46and it appears that that complete

19:49silence is really really important for a

19:52number of things and the main thing that

19:54I think it's important for is the

19:57ability to erase and break down synapses

20:00that are no longer working for us. So

20:02they encode things that are false now or

20:05they are encoding things that we um

20:08learned in the novelty encoding pathway

20:11in of our of our brain that have now

20:14been consolidated to other pathways and

20:16so we need to now erase them from the

20:18novelty encoding pathway and that is

20:20really really important for being able

20:22to continue to learn things all of our

20:24lives. So like erasing that RAM um or

20:27that I don't know what do you call those

20:29discs that you stick into computers that

20:31>> oh thumb drives thumb drives erasing

20:33your thumb drive. So that thumb drive is

20:34what you carry around all day long and

20:37then during sleep you write that thumb

20:39drive to the cortex to the long-term

20:41memory structures and you need to

20:43refresh that thumb drive and that's what

20:45happens during REM sleep when the locus

20:47realis is off and so if we're not able

20:49to do that we fill up that RAM um really

20:53quickly or that thumb drive really

20:54quickly and we're not able to learn new

20:57things even memories that are years past

21:00if you're never able to downscale that

21:02novelty encoding structure and purge it

21:05from that traumatic memory, it will stay

21:07fresh and new and then become

21:10maladaptive.

21:12>> What approaches are you aware of that

21:14can um turn down the output of locus

21:18ceruius during these phases of sleep and

21:21allow late stages of sleep each night to

21:24have their maximum positive effect.

21:26>> Is there anything that I can do besides

21:27avoiding um serotonin or noradinergic

21:30compounds? Well, I would also avoid

21:33anything just prior to going to sleep

21:35that might excite those systems. So, a

21:38lot of novelty, stress inducing video

21:40games. Try and enter sleep with as much

21:46calm as you can. So, maybe deep

21:47breathing exercises. That's a beautiful

21:50way to calm your sympathetic fight

21:52orflight system is deep breathing. And

21:55if there's a way you can make your

21:57sympathetic nervous system calm down

21:59before you go to sleep, might free for

22:02you meditation or deep breathing

22:03exercises. Might be for some a warm bath

22:06or a comforting book. Nothing too

22:08exciting, but also nothing too boring

22:11perhaps. Just something right in the

22:12middle which makes you feel happy and

22:15calm is what you should do. And if you

22:18instead go to sleep while you're anxious

22:20or hyped up, then your sleep could

22:23become maladaptive.

22:25>> I'd love for you to share with us a

22:26little bit more about um these spindles

22:28that have come up a few times.

22:30>> The density of our sleep spindles, the

22:31number that we produce per minute is

22:34well correlated with our intelligence in

22:36the first place. And that no matter what

22:38your intelligence is and no matter what

22:40your sleep spindle density is, if you

22:42learn something during the day and

22:44increase your sleep spindle density,

22:46it's really almost perfectly correlated

22:49with our ability to consolidate that

22:50information and and incorporate it into

22:53the schema that we already have in our

22:55brain. So if you try and learn something

22:57new, even if your sleep spindle density

22:59at baseline is great, if you don't

23:01increase your sleep spindles that night,

23:03you're not going to, you know, use sleep

23:05to really incorporate it. One of the

23:07things we now know through some great

23:09studies by Julie Seep and Anita Luthie

23:12is that sleep spindles are accompanied

23:14by an incredible

23:17plasticity out in the distal dendrites,

23:19the listening branches of our neurons

23:22that listen to other cortical areas. So

23:25there are proximal dendrites in our

23:27neurons that listen to the external

23:30world and are conducted through the

23:32phalamus and then there are distal

23:33dendrites which listen to an internal

23:36kind of you know conversation that's h

23:38happening in our brains. It's kind of

23:40you know our internal state really and

23:43during sleep spindles that's when those

23:45distal dendrites are able to best learn

23:49from other cortical areas and from the

23:51hippocampus. It is during sleep spindles

23:53that the hippocampus and the cortex are

23:55best connected and when that plast

23:58incredible plasticity can happen. So

24:00when I talk about schema, that's a

24:02cortical cortical thing. There's big

24:04surges of calcium into those distal

24:06dendrites and where plasticity happens

24:09in just huge amounts during that sleep

24:12spindle stage of sleep which is N2

24:14stage. There's another excitatory event

24:17that comes all the way from the brain

24:18stem and projects everywhere in our

24:20cortex which is called PGO waves which

24:23we should generalize to P waves because

24:25they come from the ponds and go to the

24:27phalamus and then the cortex happens all

24:29over the brains and that is where

24:31glutamate which is a major excitatory

24:33neurotransmitter involved in learning

24:35and plasticity is being released in big

24:38amounts also in those distal dendrites.

24:40Pwaves and spindles work together to

24:43cause plasticity and sew our schema

24:45together which could be the origins for

24:48insight and creativity. Now when P waves

24:50were first discovered, it was thought to

24:53be random because this small area that

24:56generates P waves all over the brain

24:58projects all over the phalamus and

25:00causes P waves all over. And you don't

25:02measure P waves all over the brain at

25:04the same time. In fact, it's just seems

25:06sporadic and random. And Pwaves also

25:09happening even more during REM sleep,

25:11rapid eye movement sleep. So that's why

25:14people think that REM dreams are so

25:16random is because these P waves are

25:18random and they could generate dreams

25:22because they're an internal source of

25:25excitation that kind of replaces the

25:27outside world during our dream state.

25:30And so these Pwaves, if they are random,

25:33could be the underlying reason why

25:34creativity can happen there is because

25:36we're randomly activating, co-activating

25:39different things in our brain that we

25:41can then sew together. Um, but it might

25:43not be as random as we think. So that's

25:46a caveat there.

25:47>> So locus ceruius is suppressed. So we

25:49can't release norepinephrine. We can't

25:51act out our dreams. This almost starts

25:53to sound like a little bit of a built-in

25:56um while sleeping trauma therapy. Mh.

25:59>> So please if there's anything about

26:02locust ceruius and and dreams and that

26:05can help people basically extinguish

26:08traumas or traumatic features to to real

26:10life events and we definitely want to

26:11know about them.

26:12>> Yeah. Yeah. Well, I think one of the

26:15things that people thought might help

26:17after a trauma like a school shooting or

26:19whatever you know car accident is to

26:21talk about it and in but in fact that

26:24ended up being counterproductive. And I

26:26think one of the reasons why it was

26:27counterproductive is because it didn't

26:29take you them back down. It brought them

26:32up and continued to reactivate the

26:34emotions of it, but then didn't

26:36emphasize the safety fact that it's over

26:39or help them work through how they might

26:41avoid it again in the future to calm the

26:44sympathetic nervous system down again

26:46before they went to sleep. And and in

26:48any none of these studies has sleep ever

26:50been considered, but to me that's the

26:53key part is bringing down your

26:55sympathetic nervous system before you go

26:57to sleep so that your sleep can be

26:58adaptive, your locus can shut off like

27:01it normally does or should do and then

27:04able to erase the novelty of it. The

27:08other thing that I just mentioned a

27:10minute ago was that the emotional system

27:12is highly activated in REM sleep. And

27:14that's definitely true. And that might

27:16seem counterproductive in terms of, you

27:18know, the nightmares and and how to help

27:22REM sleep be a therapeutic thing rather

27:24than reinforcing the emotionality of the

27:27trauma. And I think the key to that

27:29again is the absence of norepinephrine.

27:32So even though the emotional system is

27:35in high gear, without norepinephrine,

27:38you can actually divorce those highly

27:41activated emotions from the cognitive

27:45parts of the memory that you have just

27:48written out in that N2 stage of sleep

27:50when the sleep spindles are going. So

27:52you've just now consolidated the

27:54information that you'll need to survive

27:56and to you know to make that adaptive

27:59and now you need to divorce from that

28:02schema and from that semantic parts of

28:05memory the emotional part because

28:07whenever you remember something it's

28:09fine if you remember the being emotional

28:12at the time but you don't want to bring

28:15back and sew into that memory all of the

28:17same emotional systems. You don't want

28:18to bring back, you know, the heart rate

28:21changes and the sweating and and all of

28:23that. You want to be able to remember

28:25all the parts of it and even remember

28:27that you were traumatized and that you

28:29did cry and that you did have, you know,

28:32your heart was racing. But when you're

28:34talking about it years later, you don't

28:36want to have to relive all that.

28:37Otherwise, who who would ever want to

28:40recall a traumatic memory because you're

28:42basically putting yourself through the

28:43same trauma, which is what people with

28:45PTSD have. They don't want to recall

28:48this traumatic memory because it's

28:49reliving it like it's just happening

28:51again. So that's what we're thinking is

28:54that the emotional parts are not able to

28:57be divorced because the norphan system

29:00is not downscaled during REM sleep. And

29:02so that REM sleep serves to instead

29:06reinforce and in fact amplify the

29:08emotions because your your emotional

29:10system is up. Look, Serilla says, "Hi,

29:13re- sewing in every night the

29:16emotionality of those memories and with

29:18the memory itself."

29:20>> I must say, you've taught us a

29:22tremendous amount in um in a relatively

29:24short amount of time about the

29:26architecture of sleep, the different

29:28phases, such a wealth of information,

29:30and much of it that's actionable for

29:32people. So, I want to say thank you for

29:34taking the time to sit down and have

29:35this conversation that so many people

29:37are sure to benefit from. I know I speak

29:39for everybody when I say thank you so

29:42much. [music]

29:42>> Thank you so much.