Huberman Lab - Understanding and Using Dreams to Learn and to Forget

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Welcome to the Huberman Lab Podcast,

where we discuss science

and science-based tools for everyday life.

I’m Andrew Huberman,

and I’m a professor of neurobiology and ophthalmology

at Stanford School of Medicine.

This podcast is separate

from my teaching and research roles at Stanford.

It is, however, part of my desire

to bring you zero cost to consumer information

about science and science-related tools.

In keeping with that theme,

I’d like to thank the sponsors of today’s podcast.

Our first sponsor is Athletic Greens.

Athletic Greens is an all-in-one

vitamin mineral probiotic drink.

I’ve been taking Athletic Greens since 2012,

so I’m delighted that they’re sponsoring the podcast.

The reason I started taking Athletic Greens

and the reason I still take Athletic Greens

once or twice a day

is that it helps me cover

all of my basic nutritional needs.

It makes up for any deficiencies that I might have.

In addition, it has probiotics,

which are vital for microbiome health.

I’ve done a couple of episodes now

on the so-called gut microbiome

and the ways in which the microbiome interacts

with your immune system, with your brain to regulate mood,

and essentially with every biological system

relevant to health throughout your brain and body.

With Athletic Greens, I get the vitamins I need,

the minerals I need,

and the probiotics to support my microbiome.

If you’d like to try Athletic Greens,

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plus a year supply of vitamin D3K2.

There are a ton of data now showing that vitamin D3

is essential for various aspects of our brain

and body health.

Even if we’re getting a lot of sunshine,

many of us are still deficient in vitamin D3.

And K2 is also important

because it regulates things like cardiovascular function,

calcium in the body, and so on.

Again, go to slash Huberman

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That means the exact ratios of electrolytes are an element,

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I’ve talked many times before on this podcast

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If we have sodium, magnesium, and potassium

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If the electrolytes are not present

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They’re all delicious.

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you can go to slash Huberman.

Today’s episode is also brought to us by Thesis.

Thesis makes what are called nootropics,

which means smart drugs.

Now, to be honest, I am not a fan of the term nootropics.

I don’t believe in smart drugs

in the sense that I don’t believe

that there’s any one substance or collection of substances

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I do believe based on science, however,

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I’m pleased to announce that the Huberman Lab Podcast

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We partnered with Momentus for several important reasons.

First of all, they ship internationally

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Second of all, and perhaps most important,

the quality of their supplements is second to none,

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There, you’ll see those supplements,

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Again, that’s slash Huberman.

Today, we’re going to talk about dreaming,

learning during dreaming, and unlearning during dreaming,

in particular, unlearning of troubling emotional events.

Now, my interest in dreaming goes way back.

When I was a child, I had a friend,

and he came over one day, and he brought with him a mask

that had a little red light in the corner.

He had purchased this thing

through some magazine ad that he had seen,

and this mask was supposed to trigger lucid dreaming.

Lucid dreaming is the experience of dreaming during sleep,

but being aware that one is dreaming,

and in some cases, being able to direct one’s

dream activities.

If you’re in a lucid dream,

and you want to fly, for instance,

some people report being able to initiate

that experience of flying,

or to contort themselves into an animal,

or to transport themselves

to wherever they want within the dream.

I tried this device.

The way it worked is you put on the mask

during a waking state, wide awake,

and you’d look at the little light flashing in the corner,

and then you’d also wear it when you went to sleep at night,

and indeed, while I was asleep,

I could see the red light, presumably through my eyelids,

although for all I know, I had opened my eyes.

I don’t know, I was asleep,

and then because I was dreaming,

and I was experiencing something very vivid,

I was able to recognize that I was dreaming,

and then start to direct some of the events

within that dream.

Now, lucid dreaming occurs in about 20% of people,

and in a small percentage of those people,

they lucid dream almost every night,

so much so that many of them report their sleep

not being as restorative as it would be otherwise.

Now, all of this is to say that lucid dreaming

and dreaming are profound experiences.

We tend to feel extremely attached to our dream experience.

This may explain the phenomenon

of people who have a very intense dream,

they need to somehow tell everybody about that dream,

or tell someone about that dream.

I don’t really know what that behavior is about,

but sometimes we wake up,

and we feel so attached to what happened in this state

that we call dreaming,

that there seems to be an intense need

to share it with other people,

presumably to process it and make sense of it.

Now, numerous people throughout history

have tried to make sense of dreams

in some sort of organized way,

the most famous of which, of course, is Sigmund Freud,

who talked about symbolic representations in dreams.

A lot of that has been kind of debunked,

although I think that there’s some interest

in what the symbols of dreaming are,

and this is something that we’ll talk about

in more depth today,

although not Freudian theory in particular.

So I think in order to really think about dreams

and what to do with them,

and how to maximize the dream experience

for sake of learning and unlearning,

the best way to address this

is to look at the physiology of sleep,

to really address what do we know concretely about sleep?

So first of all, as we get sleepy,

we tend to shut our eyes,

and that’s because there are some autonomic centers

in the brain, some neurons that control

closing of the eyelids when we get sleepy,

and then we transition into sleep,

and sleep, regardless of how long we sleep,

is generally broken up into a series of 90-minute cycles,

these ultradian cycles.

So early in the night,

these 90-minute cycles tend to be comprised

more of shallow sleep and slow-wave sleep,

so stage one, stage two, et cetera,

and what we call slow-wave sleep.

I’ll go into detail about what all this means in a moment.

And we tend to have less so-called REM sleep,

R-E-M sleep, which stands for rapid eye movement sleep,

and I’ll talk about rapid eye movement sleep in detail.

So early in the night,

a lot more slow-wave sleep and less REM.

For every 90-minute cycle that we have

during a night of sleep,

we tend to start having more and more REM sleep,

so more of that 90-minute cycle

is comprised of REM sleep and less of slow-wave sleep.

Now, this is true regardless of whether or not

you wake up at the middle of the night

to use the restroom or your sleep is broken.

The more sleep you’re getting across the night,

the more REM sleep you’re going to have.

And REM sleep and non-REM, as I’ll refer to it,

have distinctly different roles in learning and unlearning,

and they are responsible for learning and unlearning

of distinctly different types of information.

And this has enormous implications

for learning of motor skills,

for unlearning of traumatic events,

or for processing emotionally challenging,

as well as emotionally pleasing events.

And as we’ll see,

one can actually leverage their daytime activities

in order to access more slow-wave sleep,

or non-REM sleep, as we’ll call it,

or more REM sleep,

depending on your particular emotional and physical needs.

So it’s really a remarkable stage of life

that we have a lot more control and power over

than you might believe.

We’ll also talk about lucid dreaming.

We’re also going to talk about hallucinations

and how drug-induced hallucinations

have a surprising similarity to a lot of dream states,

and yet some really important differences.

Okay, so let’s start by talking about slow-wave sleep

or non-REM sleep.

Now, I realize that slow-wave sleep and non-REM sleep

aren’t exactly the same thing.

So for you sleep aficionados out there,

I am lumping right now.

As we say in science,

there are lumpers and there are splitters,

and I am both.

Sometimes I lump, sometimes I split.

For sake of clarity and ease of conversation right now,

I’m going to be a lumper.

So when I say slow-wave sleep,

I mean non-REM sleep generally,

although I acknowledge there is a distinction.

Slow-wave sleep.

So slow-wave sleep is characterized

by a particular pattern of brain activity

in which the brain is metabolically active,

but that there’s these big sweeping waves of activity

that include a lot of the brain.

If you want to look this up there,

you can find evidence for sweeping of waves

of neural activity across association cortex,

across big swaths of the brainstem,

the so-called pons chiniculate occipital pathway.

This is brainstem, thalamus, and then cortex.

For those of you that are interested,

although more of that is going to occur in REM sleep.

Now, the interesting thing about slow-wave sleep

are the neuromodulators that tend to be associated with it

that are most active and least active

during slow-wave sleep, and here’s why.

To remind you, neuromodulators are these chemicals

that act rather slowly,

but their main role is to bias particular brain circuits

to be active and other brain circuits to not be active.

These are like the music playlist.

Think of neuromodulators,

and these come in the names of acetylcholine,

norepinephrine, serotonin, and dopamine.

Think of them as suggesting playlists on your audio device.

So classical music is distinctly different in feel and tone

and a number of other features from like third-wave punk

or from hip hop, right?

So think of them as biasing toward particular genres

of neural circuit activity, okay?

Mellow music versus really aggressive fast music

or rhythmic music that includes lyrics

versus rhythmic music that doesn’t include lyrics.

That’s more or less the way

to think about these neuromodulators,

and they are associated as a consequence

with certain brain functions.

So we know, for instance,

and just to review, acetylcholine in waking states

is a neuromodulator that tends to amplify the activity

of brain circuits associated with focus and attention.

Norepinephrine is a neuromodulator

that tends to amplify the brain circuits

associated with alertness and the desire to move.

Serotonin is the neuromodulator that’s released

and tends to amplify the circuits in the brain and body

that are associated with bliss

and the desire to remain still.

And dopamine is the neuromodulator that’s released

and is associated with amplification

of the neural circuits in the brain and body

associated with pursuing goals and pleasure and reward, okay?

So in slow-wave sleep, something really interesting happens.

There’s essentially no acetylcholine.

Acetylcholine production and release and action

from the two major sites, which are in the brainstem,

which from a nucleus, the parabigeminal nucleus,

if you really want to know,

or from the forebrain, which is nucleus basalis,

and you don’t need to know these names,

but if you’d like, that’s why I put them out there.

Acetylcholine production plummets.

It’s just almost to zero.

And acetylcholine, as I just mentioned,

is associated with focus.

So you can think of slow-wave sleep

as these big sweeping waves of activity through the brain

and a kind of distortion of space and time

so that we’re not really focusing on any one thing.

Now, the other molecules that are very active at that time

are norepinephrine, which is a little bit surprising

because normally in waking states,

norepinephrine is going to be associated

with a lot of alertness and the desire to move,

but there’s not a ton of norepinephrine around

in slow-wave sleep, but it is around.

So there’s something associated

with the movement circuitry going on in slow-wave sleep.

And remember, this is happening mostly

at the beginning of the night.

Your sleep is dominated by slow-wave sleep.

So no acetylcholine, very little norepinephrine,

although there is some, and a lot of serotonin.

And serotonin, again, is associated with this desire,

this sensation of kind of bliss or wellbeing,

but not a lot of movement.

And during sleep, you tend not to move.

Now, in slow-wave sleep, you can move.

You’re not paralyzed, so you can roll over.

If people are going to sleepwalk,

typically it’s going to be during slow-wave sleep.

And what studies have shown

through some kind of sadistic experiments

where people are deprived specifically of slow-wave sleep,

and that can be done by waking them up

as soon as the electrode recordings show

that they’re in slow-wave sleep,

or by chemically altering their sleep

so that it biases them away from slow-wave sleep,

what studies have shown is that motor learning

is generally occurring in slow-wave sleep.

So let’s say the day before you go to sleep,

you were learning some new dance move,

or you were learning some specific motor skill,

either a fine motor skill or a coarse motor skill.

So let’s say it’s a new form of exercise

or some new coordinated movements.

This could be coordinated movement

at the level of the fingers,

or it could be coordinated movement

at the level of the whole body and large limb movements.

It could involve other people,

or it could be a solo activity.

Learning of those skills

is happening primarily during slow-wave sleep

in the early part of the night.

In addition, slow-wave sleep has been shown to be important

for the learning of detailed information.

Now, this isn’t always cognitive information.

We’re going to talk about cognitive information,

but the studies that have been done along these lines

involve having people learn very detailed information

about very specific rules

and the way that certain words are spelled.

They tend to be challenging words.

So if people are tested

in terms of their performance on these types of exams,

and they’re deprived of slow-wave sleep,

they tend to perform very poorly.

So we can think of slow-wave sleep

as important for motor learning, motor skill learning,

and for the learning of specific details

about specific events.

And this turns out to be fundamentally important

because now we know that slow-wave sleep

is primarily in the early part of the night,

and motor learning is occurring primarily

early in the night,

and detail learning is occurring early in the night.

Now, for those of you that are waking up

after only three, four hours of sleep,

this might be informative.

This might tell you a little something

about what you are able to learn and not able to learn

if that were to be the only sleep that you get,

although hopefully that’s not the only sleep that you get.

But we’re going to dive deep into how it is

that one can maximize motor learning

in order to extract, say, more detailed information

about coordinated movements

and how to make them faster or slower.

So that might be important for certain sports.

It might be almost certainly important for certain sports.

It’s going to be important

for any kind of coordinated movement,

like, say, learning to play the piano,

or, for instance, how to learn synchronized movements

with somebody else.

So maybe, I mentioned the example of dance earlier.

If you, like me, a few years ago,

I set out to learn tango

because I have some Argentine relatives,

and I was abysmal.

I need to return to that at some point.

I was just abysmal.

And one of the worst things

about being abysmal and learning dance

is that somebody else has to suffer the consequences also.

So, I don’t know, maybe in the month on neuroplasticity,

I’ll explore that again as a self-experimentation.

But the key things to know are slow-wave sleep’s involved

in motor learning and detailed learning.

There’s no acetylcholine around at that time,

has this big amplitude activity

sweeping throughout the brain,

and that there’s the release of these neuromodulators,

norepinephrine and serotonin.

And again, that’s all happening early in the night.

So, athletes, people that are concerned about performance,

if you happen to wake up after just a couple hours

of three, four hours of sleep

because you’re excited about a competition the next day,

presumably, if you’ve already trained the skills

that you need for the event,

you should be fine to engage in that particular activity.

Now, it’s always going to be better

to get a full night’s sleep.

And a full night’s sleep for you is six hours,

and it’s always going to be better to get more sleep

than it is to get less.

However, I think some people get a little bit

overly concerned that if they didn’t get

their full night’s sleep

before some sort of physical event,

that their performance is going to plummet.

Presumably, if you’ve already learned what you need to do

and it’s stored in your neural circuits,

and you know how to make those coordinated movements,

what the literature on slow-wave sleep suggests

is that you would be replenished,

that the motor learning and the recovery from exercise

is going to happen early in the night.

So we’ll just pause there and kind of shelve that

for a moment, and then we’re going to come back to it.

But I want to talk about REM sleep,

or rapid eye movement sleep.

REM sleep and rapid eye movement sleep,

as I mentioned before, occurs throughout the night,

but you’re going to have more of it.

A larger percentage of these 90-minute sleep cycles

is going to be comprised of REM sleep

as you get toward morning.

REM sleep is fascinating.

It was discovered in the 50s

when a sleep laboratory in Chicago,

the researchers observed that people’s eyes

were moving under their eyelids.

Now, something very important that we’re going to address

when we talk about trauma later

is that the eye movements are not just side to side,

they’re very erratic in all different directions.

One thing that I don’t think anyone,

I’ve never heard anyone really talk about publicly

is why eye movements during sleep, right?

Eyes are closed, and sometimes people’s eyelids

will be a little bit open and their eyes are darting around,

especially in little kids.

I don’t suggest you do this, I’m not even sure it’s ethical,

but it has been done where you pull back the eyelids

of a kid while they’re sleeping

and their eyes are kind of darting all over the place.

I think people do this to their passed out friends

at parties and things like that.

So again, I don’t suggest you do it,

but I’m telling you it because it’s been done before

and therefore you don’t have to do it again.

But rapid eye movement sleep is fascinating

and occurs because there are connections

between the brainstem, an area called the pons,

and areas of the thalamus and the top of the brainstem

that are involved in generating movements

in different directions, sometimes called saccades,

although sometimes during rapid eye movement sleep,

it’s not just rapid, it’s kind of a jittery

side to side thing, and then the eyeballs kind of roll.

It’s really pretty creepy to look at if you see.

So what’s happening there is the circuitry

that is involved in conscious eye movements

is kind of going haywire, but it’s not haywire.

It’s these waves of activity from the brainstem

up to the so-called thalamus,

which is an area that filter sensory information

and then up to the cortex.

And the cortex, of course,

is involved in conscious perceptions.

So in rapid eye movement sleep,

there are a couple things that are happening

besides rapid eye movements.

The main ones are that they’re, I should say,

in contrast to slow wave sleep, in REM sleep,

serotonin is essentially absent, okay?

So this molecule, this neuromodulator

that tends to create the feeling of bliss and wellbeing

and just calm placidity is absent, all right?

So that’s interesting.

In addition to that, norepinephrine,

this molecule that’s involved in movement and alertness

is absolutely absent.

It’s probably one of the few times in our life

that epinephrine is essentially at zero activity

within our system.

And that has a number of very important implications

for the sorts of dreaming that occur during REM sleep

and the sorts of learning that can occur

in REM sleep and unlearning.

First of all, in REM sleep, we are paralyzed.

We are experiencing what’s called atonia,

which just means that we’re completely laid out

and paralyzed.

We also tend to experience whatever it is

that we’re dreaming about as a kind of hallucination

or a hallucinatory activity.

Long ago, I looked into hallucinations and dreaming.

I was just fascinated by this in high school.

And there’s some great books on this

if you’re interested in exploring the relationship

between hallucinations and dreaming.

The most famous of which are from a guy,

researcher at Harvard, Alan Hobson,

wrote a book called Dream Drugstore

and talked all about the similarities

between drugs that induce hallucinations

and dreaming in REM.

So you can explore that if you like.

So in REM, our eyes are moving,

but the rest of our body is paralyzed

and we are hallucinating.

There’s no epinephrine around.

Epinephrine doesn’t just create a desire

to move and alertness.

It is also the chemical signature of fear and anxiety.

It’s what’s released from our adrenal glands

when we experience something that’s fearful or alerting.

So if a car suddenly screeches in front of us

or we get a troubling text message,

adrenaline is deployed into our system.

Adrenaline is epinephrine.

Those are equivalent molecules.

And epinephrine isn’t just released from our adrenals.

It’s also released within our brain.

So there’s this weird stage of our life

that happens more toward morning that we call REM sleep,

where we’re hallucinating

and having these outrageous experiences in our mind,

but the chemical that’s associated with fear and panic

and anxiety is not available to us.

And that turns out to be very important.

And you can imagine why that’s important.

It’s important because it allows us to experience things,

both replay of things that did occur,

as well as elaborate contortions

of things that didn’t occur.

And it allows us to experience those

in the absence of fear and anxiety.

And that, it turns out,

is very important for adjusting our emotional relationship

to challenging things that happened to us

while we were awake.

Those challenging things can sometimes be in the form

of social anxiety or just having been working very hard

or concern about an upcoming event.

Or sometimes people report, for instance,

dreams where they find themselves late to an exam

or naked in public or in some sort of situation

that would be very troubling to them.

And that almost certainly occurs during REM sleep.

So we have this incredible period of sleep

in which our experience of emotionally laden events

is dissociated, it’s chemically blocked

from us having the actual emotion.

Now, probably immediately some of you are thinking,

well, what about nightmares?

I have nightmares and those carry a lot of emotion

or sometimes I’ll wake up in a panic.

Let’s consider each of those two things separately

because they are important in understanding REM sleep.

There’s a good chance that nightmares are occurring

during slow wave sleep.

There are actually some drugs

that I don’t suggest people take,

in fact, so much so I’m not going to mention them,

that give people very kind of scary or eerie dreams

and this kind of feeling that things are pursuing them

or that they can’t move when they are being chased.

That’s actually a common dream that I’ve had

is I guess it’s more or less a nightmare.

The feeling that one is paralyzed and can’t move

and is being chased.

A lot of people have said, oh, that must be in REM sleep

because you’re paralyzed and so you’re dreaming

about being paralyzed and you can’t move.

I think that’s probably false.

The research says that because norepinephrine

is absent during REM sleep,

it’s very unlikely that you can have

these intense fearful memories.

So those are probably occurring in slow wave sleep.

Although there might be instances

where people have nightmares in REM sleep.

The other thing is some people experience,

certainly I’ve had this experience of waking up

and feeling very stressed about whatever it was

that I happen to be thinking about

or dreaming about in the moments before.

And that’s an interesting case of an invasion

of the dream state into the waking state.

And the moment you wake up, epinephrine is available.

So the research on this isn’t fully crystallized,

but most of it points in the direction

of the experience of waking up and feeling very panicked.

Maybe, I want to highlight may,

but maybe that you were experiencing something

that was troubling in the daytime.

You’re repeating that experience in your sleep.

Epinephrine is not available

and therefore the brain circuits associated

with fear and anxiety are shut off.

And so you’re able to process those events.

And then suddenly you wake up

and there’s a surge of adrenaline, of epinephrine

that’s now coupled to that experience.

So nightmares very likely in slow wave sleep

and that kind of panic on waking from something

very likely to be an invasion of the thoughts

and ideas, however distorted in REM sleep

invading the waking state.

In fact, that brings to mind something

that I’ve mentioned once before,

but I want to mention again, this atonia,

this paralysis that we experienced during sleep

can invade the waking state.

Many people report the experience of waking up

and being paralyzed.

They’re legitimately waking up, it’s not a dream.

Waking up and being paralyzed and it is terrifying.

I’ve had this happen before.

It is, I can tell you terrifying to be wide awake.

And as far as I could tell fully conscious,

but unable to move.

And then generally you can jolt yourself out of it

in a few seconds, but it is quite frightening.

Now, some people actually experience waking up

being fully paralyzed and hallucinating.

And there is a theory in the academic

and scientific community at least

that what people report as alien abductions

have a certain number of core characteristics

that map quite closely yearly similarly

to these experiences.

A lot of reports of alien abduction

involve people being unable to move,

seeing particular faces, hallucinating extensively,

feeling like their body is floating

or they were transported.

This is very similar to the experience

of invasion of atonia into the waking state.

Waking up and still being paralyzed

as well as the hallucinations that are characteristic

of dreaming in REM sleep.

Now, I’m not saying that people’s alien abductions

were not legitimate alien abductions.

How could I?

I wasn’t there.

And if I was there, I wouldn’t tell you

because that would make me an alien

and I wouldn’t want you to know.

But it is quite possible

that people are experiencing these things

and they are an invasion of the sleep state

into the waking state.

And they can last several minutes or longer.

And because in dreams, space and time are distorted.

Our perception of these events could be

that they lasted many hours

and we can really feel as if they lasted many hours

when in fact they took only moments.

And we’re going to return to distortion

of space and time in a little bit.

So to just recap where we’ve gone so far,

slow wave sleep early in the night,

it’s been shown to be important for motor learning

and for detail learning.

REM sleep has a certain dream component

when which there’s no epinephrine.

Therefore we can’t experience anxiety.

We are paralyzed.

Those dreams tend to be really vivid

and have a lot of detail to them.

And yet in REM sleep, what’s very clear

is that the sorts of learning that happen in REM sleep

are not motor events.

It’s more about unlearning of emotional events.

And now we know why,

because the chemicals available

for really feeling those emotions are not present.

Now that has very important implications.

So let’s address those implications from two sides.

First of all, we should ask what happens

if we don’t get enough REM sleep?

And a scenario that happens a lot

where people don’t get enough REM sleep is the following.

I’ll just explain the one that I’m familiar with

because it happens to me a lot,

although I figured out ways to adjust.

I go to sleep around 10, 30, 11 o’clock.

I fall asleep very easily.

And then I wake up around three or 4 a.m.

I now know to use a NSDR, a non-sleep deep rest protocol.

And that allows me to fall back asleep.

Even though it’s called non-sleep deep rest,

it’s really allows me to relax my body and brain.

And I tend to fall back asleep and sleep till about 7 a.m.,

during which time I get a lot of REM sleep.

And I know this because I’ve measured it.

And I know this because my dreams tend to be very intense

of the sort that we know is typical of REM sleep.

In this scenario,

I’ve gotten my slow wave sleep early in the night

and I’ve got my REM sleep toward morning.

However, there are times when I don’t go back to sleep.

Maybe I have a flight to catch, that’s happened.

Sometimes I’ve got a lot on my mind

and I don’t go back to sleep.

I can tell you, and you’ve probably experienced,

that the lack of REM sleep

tends to make people emotionally irritable.

It tends to make us feel

as if the little things are the big things.

So it’s very clear from laboratory studies

where people have been deprived selectively of REM sleep

that our emotionality tends to get a little bit unhinged

and we tend to catastrophize small things.

We tend to feel like the world is really daunting.

We’re never going to move forward in the ways that we want.

We can’t unlearn the emotional components

of whatever it is that’s been happening,

even if it’s not traumatic.

The other thing that happens in REM sleep

is a replay of certain types of spatial information

about where we were and why we were in those places.

And this maps to some beautiful data

and studies that were initiated

by a guy named Matt Wilson at MIT years ago,

showing that in rodents,

and it turns out in non-human primates and in humans,

there’s a replay of spatial information during REM sleep

that almost precisely maps to the activity

that we experienced during the day

as we move from one place to another.

So here’s a common world scenario.

You go to a new place,

you navigate through that city or that environment.

This place doesn’t have to be at the scale of a city.

It can be a new building,

could be finding particular rooms, new social interaction.

You experience that, and if it’s important enough,

that becomes solidified a few days later,

and you won’t forget it.

If it’s unimportant, you’ll probably forget it.

During REM sleep, there’s a literal replay

of the exact firing of the neurons that occurred

while you were navigating that same city

you’re building earlier.

So REM sleep seems to be involved in the generation

of this detailed spatial information.

But what is it that’s actually happening in REM sleep?

So there’s this uncoupling of emotion,

but most of all, what’s happening in REM sleep

is that we’re forming a relationship

with particular rules or algorithms.

We’re starting to figure out,

based on all the experience that we had during the day,

whether or not it’s important that we avoid certain people

or that we approach certain people,

whether or not it’s important that when we enter a building

that we go into the elevator and turn left

where the bathroom is, for instance,

these general themes of things and locations

and how they fit together, and that has a word.

It’s called meaning.

During our day, we’re experiencing all sorts of things.

Meaning is how we each individually piece together

the relevance of one thing to the next, right?

So if I suddenly told you that this pen

was downloading all the information to my brain

that was important to deliver this information,

you’d probably think I was a pretty strange character

because typically we don’t think of pens

as downloading information into brains,

but if I told you that I was getting information

from my computer that was allowing me to say things to you,

you’d say, well, that’s perfectly reasonable,

and that’s because we have a clear

and agreed upon association with computers

and information and memory,

and we don’t have that same association with pens.

You might say, well, duh,

but something in our brain

needs to solidify those relationships

and make sure that certain relationships don’t exist,

and it appears that REM sleep is important for that

because when you deprive yourself or people of REM,

they start seeing odd associations.

They tend to lump or batch things.

I know this from my own experience.

If I’ve ever been sleep-deprived,

which unfortunately happens too often

because I’m terrible with deadlines,

pull an all-nighter,

the word the starts to look like it’s spelled incorrectly,

and the is a very simple word to spell,

but things start to look a little distorted,

and we know that if people are deprived of REM sleep

for very long periods of time, they start hallucinating.

They literally start seeing relationships

and movement of objects that isn’t happening,

and so REM sleep is really

where we establish the emotional load,

but where we also start discarding

of all the meanings that are irrelevant,

and if you think about emotionality,

a lot of over-emotionality or catastrophizing

is about seeing problems everywhere,

and you could imagine why that might occur

if you start linking the web

of your experience too extensively.

It’s very important in order to have healthy,

emotional, and cognitive functioning

that we have fairly narrow channels

between individual things.

If we see something on the news that’s very troubling,

well, then it makes sense to be very troubled,

but if we’re troubled by everything

and we start just saying everything is bothering me

and I’m feeling highly irritable

and everything is just distorting and troubling me,

chances are we are not actively removing the meaning,

the connectivity between life experiences

as well as we could,

and that almost always maps back to a deficit in REM sleep,

so REM sleep is powerful and has this amazing capacity

to eliminate the meanings that don’t matter.

It’s not that it exacerbates the meanings that do matter,

but it eliminates the meanings that don’t matter,

and that bears a striking resemblance

to what happens early in development.

This isn’t a discussion about early in development,

but early in development,

the reason a baby can’t generate coordinated movements

and the reason why children can get very emotional

about what seems like trivial events

or what adults know to be trivial events,

like, oh, the ice cream shop is closed,

and then the kid just dissolves

into a puddle of tears,

and the parents go, okay, well,

it’ll be open again another time.

Children, one of the reasons

that they can’t generate coordinated movement

or place that event of the ice cream shop being closed

into a larger context

is because they have too much connectivity,

and much of the maturation of the brain and nervous system

that brings us to the point of being emotionally stable,

reasonable, rational human beings

is about elimination of connections between things,

so REM sleep seems to be where we uncouple

the potential for emotionality between various experiences,

and that brings us

to the absolutely fundamental relationship

and similarity of REM sleep

to some of the clinical practices

that have been designed to eliminate emotionality

and help people move through trauma

and other troubling experiences,

whether or not those troubling experiences

are a death in the family or of a close loved one,

something terrible that happened to you or somebody else,

or an entire childhood,

or some event that in your mind and body

is felt as and experienced as bad, terrible, or concerning.

Many of you perhaps have heard of trauma treatments

such as EMDR, Eye Movement Desensitization Reprocessing,

or ketamine treatment for trauma,

something that recently became legal

and is in fairly widespread clinical use.

Interestingly enough, EMDR and ketamine

at kind of a core level

bear very similar features to REM sleep.

So let’s talk about EMDR first.

EMDR, Eye Movement Desensitization Reprocessing,

is something that was developed

by a psychologist, Francine Shapiro.

She actually was in Palo Alto.

And the story goes that she was walking,

not so incidentally,

in the trees and forests behind Stanford,

and she was recalling a troubling event in her own mind.

So this would be from her own life.

And she realized that as she was walking,

the emotional load of that experience

was not as intense or severe.

She extrapolated from that experience

of walking and not feeling as stressed

about the stressful event,

to a practice that she put into work

with her clients, with her patients,

and that now has become fairly widespread.

It’s actually one of the few behavior treatments

that are approved by the American Psychological Association

for the Treatment of Trauma.

What she had her clients and patients do

was move their eyes from side to side

while recounting some traumatic or troubling event.

Now, this was, of course, in the clinic.

And I’m guessing that she removed the walking component

and just took the eye movement component to the clinic,

because while it would be nice to go on therapy sessions

with your therapist and take walks,

it has, there are certain boundaries to that,

such as confidentiality.

You know, if there are a lot of people around,

the person might not feel as open to discussing things,

or weather barriers and things like that.

You know, if it’s raining or hailing outside,

it gets tough to do.

Why eye movements?

Well, she never really said why eye movements,

but soon I’ll tell you why the decision

to select these lateralized eye movements

for the work in the clinic was the right one.

So these eye movements, they look silly.

I’ll do them because that’s why I’m here.

They look silly, but they basically involve

sitting in a chair and moving one’s eyes from side to side,

not while talking, but, you know, for me, you know,

and then recounting the event.

So it’s sometimes talking while moving the eyes,

but usually it was moving the eyes from side to side

for 30, 60 seconds,

then describing this challenging procedure.

Now, as a vision scientist who also works on stress,

when I first heard this, I thought it was crazy, frankly.

People would ask me about EMDR,

and I just thought, that’s crazy.

I went and looked up some of the theories

about why EMDR might work,

and there were a bunch of theories.

Oh, it mimics the eye movements during REM sleep.

That was one.

Turns out that’s not true, and I’ll explain why.

The other one was, oh, it synchronizes the activity

on the two sides of the brain.

Well, sort of.

I mean, when you look into both sides

of the binocular visual field,

you activate the visual cortex,

but this whole idea of synchrony

between the two sides of the brain

is something that I think modern neuroscience

is starting to, let’s just say,

gently or not so gently move away

from this whole left brain business.

It turns out, however,

that eye movements of the sort that I just did

and that Francine Shapiro took from this walk experience

and brought to her clients in the clinic

are the sorts of eye movements that you generate

whenever you’re moving through space,

when you are self-generating that movement.

So not so much when you’re driving a car,

but certainly if you were riding a bicycle

or you were walking or you were running,

you don’t realize it,

but you have these reflexive subconscious eye movements

that go from side to side,

and they are associated with the motor system.

So when you move forward, your eyes go like this.

There’ve been a number of studies

showing that these lateralized eye movements

helped people move through

or dissociate the emotional experience

of particular traumas with those experiences

such that they could recall those experiences

after the treatment and not feel stressed about them

or they didn’t report them as traumatic any longer.

Now, the success rate wasn’t 100%,

but they were statistically significant

in a number of studies.

And yet there are still some critics of EMDR.

And frankly, for a long time,

I still thought, well, I don’t know,

this just seems like kind of a hack.

It just seems like kind of a,

this is something for which we don’t know the mechanism

and we can’t explain.

But in the last five years,

there have been no fewer than five,

and there’s a sixth on the way,

high-quality peer-reviewed manuscripts

published in Journal of Neuroscience,

Neuron, Cell Press Journal, excellent journal,

Nature, excellent journal.

These are very stringent journals and papers

showing that lateralized eye movements

of the sort that I just did,

and if you’re just listening to this,

it’s just sweeping, moving the eyes from side to side

with eyes open, that those eye movements,

but not vertical eye movements,

suppress the activity of the amygdala,

which is this brain region that is involved

in threat detection, stress, anxiety, and fear.

There are some forms of fear

that are not amygdala-dependent,

but the amygdala, it’s not a fear center,

but it is critical for the fear response

and for the experience of anxiety.

So that’s interesting.

We’ve got a clinical tool now

that indeed shows a lot of success

in a good number of people

where eye movements from side to side

are suppressing the amygdala,

and the general theme is to use those eye movements

to suppress the fear response,

and then to recount or repeat the experience,

and over time, uncouple the heavy emotional load,

the sadness, the depression, the anxiety, the fear,

from whatever it was that happened that was traumatic.

This is important to understand

because I’d love to be able to tell somebody

who had a traumatic experience

that they would forget that experience,

but the truth is you never forget the traumatic experience.

What you do is you remove the emotional load.

Eventually, it really does lose its potency.

The emotional potency is alleviated.

Now, EMDR, I should just mention,

tends to be most successful for single event

or very specific kinds of trauma that happen over and over,

as opposed to, say, an entire childhood or an entire divorce.

It tends to be most effective

for single event kinds of things,

car crashes, et cetera,

where people can really recall the events

in quite a lot of detail.

So it’s not for everybody, and it should be done,

if it’s going to be done for trauma,

it should be done in a clinical setting

with somebody who’s certified to do this,

but that bears a lot of resemblance to REM sleep, right?

This experience in our sleep where our eyes are moving,

although in a different way,

but we don’t have the chemical, epinephrine,

in order to generate the fear response,

and yet we’re remembering the event

from the previous day or days.

Sometimes in REM sleep,

we think about things that happened a long, long time ago.

So that’s interesting.

And then now there’s this new treatment,

this chemical treatment with the drug ketamine,

which also bears a lot of resemblance

to the sorts of things that happen in REM sleep.

Ketamine is getting a lot of attention now,

and I think a lot of people

just don’t realize what ketamine is.

Ketamine is a dissociative anesthetic.

It is remarkably similar to the drug called PCP,

which is certainly a hazardous drug for people to use.

Ketamine and PCP both function to disrupt the activity

of a particular receptor in the brain

called the NMDA receptor, N-methyl-D-aspartate receptor.

This is a receptor that’s in the surface of neurons

or on the surface of neurons

for which most of the time it’s not active.

But when something very extreme happens,

and there’s a lot of activity in the neural pathway

that impinges on that receptor,

it opens and it allows the entry of molecules, ions,

that trigger a cellular process

that we call long-term potentiation.

And long-term potentiation translates

to a change in connectivity so that later

you don’t need that intense event

for the neuron to become active again.

Let me clarify a little bit of this.

The NMDA receptor is gated by intense experience.

One way you can think about this

is typically I walk in my home,

I might make some food and sit down at my kitchen table,

and I don’t think anything about explosions.

But were I to come home one night,

sit down to a bowl of chicken soup,

and there was a massive explosion,

the neurons that are associated with chicken soup

in my kitchen table would be active in a way

that was different than they were previously,

and would be coupled to this experience of explosions

such that the next time and perhaps every other time

that I go to sit down at the kitchen table,

no matter how rational I am

about the origins of that explosion,

maybe it was a gas truck that was down the road

and there’s no reason to think it’s there today,

but I would have the same experience.

Those neurons would become active

and I’d get an increase in heart rate,

I’d get an increase in sweating, et cetera.

Ketamine blocks this NMDA receptor

and prevents that crossover

and the addition of meaning to the kitchen table,

kitchen soup, excuse me,

chicken soup explosion experience.

So how is ketamine being used?

Ketamine is being used to prevent learning of emotions

very soon after trauma.

So ketamine is being stocked

in a number of different emergency rooms

if people are brought in quickly,

and these are hard to describe even,

but a horrible experience of somebody seeing a loved one

next to them killed in a car accident

and they were driving that car.

This isn’t for everybody, certainly,

and you need to talk to your physician,

but ketamine is being used

so they might infuse somebody with ketamine

so that their emotion can still occur,

but that the plasticity,

the change in the wiring of their brain

won’t allow that intense emotion

to be attached to the experience.

Now, immediately, you can imagine

the sort of ethical implications of this, right?

Because certain emotions need to be coupled to experiences.

I’m not saying that people should be using ketamine

or shouldn’t be using ketamine,

certainly not recreationally, it’s quite dangerous.

It can be lethal, and like PCP,

it can cause pretty dramatic changes

in perception and behavior,

but in the clinical setting,

the basis of ketamine-assisted therapies

is really to remove emotion,

and I think the way I’ve been hearing about it

talked about in the general public

is a lot of people think it’s a little bit more

like the kind of psilocybin trials or the MDMA trials

where it’s about becoming more emotional

or getting in touch with a certain experience.

Ketamine is about becoming dissociative

or removed from the emotional component of the experience.

So now we have ketamine, which chemically blocks plasticity

and prevents the connection

between an emotion and an experience.

That’s a pharmacologic intervention.

We have EMDR, which is this eye movement thing

that is designed to suppress the amygdala

and is designed to remove emotionality

while somebody recounts an experience,

and we have REM sleep where the chemical epinephrine

that allows for signaling of intense emotion

and the experience of a tense emotion

in the brain and body is not allowed.

And so we’re starting to see a organizational logic,

which is that a certain component of our sleeping life

is acting like therapy.

And that’s really what REM sleep is about.

So we should really think about REM sleep

and slow wave sleep as both critical.

Slow wave sleep for motor learning and detailed learning,

REM sleep for attaching of emotions

to particular experiences,

and then for making sure that the emotions

are not attached to the wrong experiences

and for unlearning emotional responses

if they’re too intense or severe.

And this all speaks to the great importance

of mastering one’s sleep,

something that we talked about in episode two of the podcast

and making sure that if life has disruptive events,

either due to travel or stress or changes in school

or food schedule,

something that we talked about in episodes three and four,

that one can still grab a hold and manage one’s sleep life

because fundamentally the unlearning of emotions

that are troubling to us

is what allows us to move forward in life.

And indeed the REM deprivation studies

show that people become hyper-emotional,

they start to catastrophize.

And it’s no surprise therefore

that sleep disturbances correlate

with so many emotional and psychological disturbances.

It’s just, by now it should just be obvious

why that will be the case.

In fact, the other day I was in a discussion

with a colleague of mine who’s down in Australia,

Dr. Sarah McKay, I’ve known her for two decades now

from the time she was at Oxford.

And Sarah studies, among other things,

menopause in the brain.

And she was saying that a lot of the emotional effects

of menopause actually are not directly related

to the hormones.

There’ve been some really nice studies

showing that the disruptions in temperature regulation

and menopause mapped to changes in sleep regulation

that then impact emotionality

and an inability to correctly adjust the circuits

related to emotionality.

And I encourage you to look at her work.

We’ll probably have her as a guest on the podcast

at some point in the future

because she’s so knowledgeable about those sorts of issues

as well as issues related to testosterone

and in people with all sorts

of different chromosomal backgrounds.

So sleep deprivation isn’t just deprivation of energy.

It’s not just deprivation of immune function.

It is deprivation of self-induced therapy

every time we go to sleep, okay?

So these things like EMDR and ketamine therapies

are in-clinic therapies, but REM sleep is the one

that you’re giving yourself every night when you go to sleep

which raises, I think, the other important question

which is how to get and how to know

if you’re getting the appropriate amount

of REM sleep and slow-wave sleep.

So that’s what we’ll talk about next.

So how should one go about getting the appropriate amount

of slow-wave sleep and REM sleep

and knowing that you’re getting the right amount?

Well, short of hooking yourself up to an EEG,

it’s going to be tough to get exact measurements

of brain states from night to night.

Some people nowadays are using things like the Oura Ring

or a Whoop band or some other device

to measure the quality and depth

and duration of their sleep.

And for many people, those devices can be quite useful.

Some people are only gauging their sleep

by way of whether or not they feel rested,

whether or not they feel like they’re learning

and they’re getting better or not.

There are some things that one can really do.

And the first one might surprise you

in light of everything I’ve said

and probably everything you’ve heard about sleep.

There was a study done by a Harvard undergraduate

Emily Hoagland who was in Robert Strickgold’s lab

at the time.

And that study explored how variations

in total sleep time related to learning

as compared to total sleep time itself.

And to summarize the study,

what they found was that it was more important

to have a regular amount of sleep each night

as opposed to the total duration.

In other words, and what they showed

was that improvements in learning

or deficits in learning were more related

to whether or not you got six hours, six hours,

five hours, six hours.

That was better than if somebody got, for instance,

six hours, 10 hours, seven hours, four or five hours.

So you might say, well, that’s crazy

because I thought we’re just all supposed to get more sleep

and there’s more REM towards morning.

It turns out that for sake of learning new information

and performance on exams in particular,

that’s what was measured.

Limiting the variation in the amount of your sleep

is at least as important and perhaps more important

than just getting more sleep overall.

And I think this will bring people great relief,

many people great relief who are struggling

to quote unquote, get enough sleep.

Remember a few episodes ago,

I talked about the difference between fatigue and insomnia.

Fatigue is tends to be when we are tired,

insomnia tends to lead to a sleepiness during the day

when we’re falling asleep and you don’t want that.

You don’t want either of those things really.

But I found it striking that the data from this study

really point to the fact that consistently getting

about the same amount of sleep

is better than just getting more sleep.

And I think nowadays so many people are just aiming

for more sleep and they’re rather troubled about the fact

that they’re only getting five hours

or they’re only getting six hours in some cases.

It may be the case that they are sleep deprived

and they need more sleep,

but some people just have a lower sleep need.

And I find great relief personally in the fact

that consistently getting for me about six hours

or six and a half hours is going to be more beneficial

than constantly striving for eight or nine

and finding that some nights I’m getting five

and sometimes I’m getting nine and varying around the mean.

As I recall, and I think I’m going to get this

precisely right, but if not, I know that I’m at least close

for every hour variation in sleep,

regardless of whether or not I was more sleep

than one typically got,

there was a 17% reduction in performance

on this particular exam type.

And so this is powerful.

This means that we should strive

for a regular amount of sleep.

And for some of us, that means falling asleep

and waking up and going back to sleep.

For some people it means falling asleep

and waking up and not getting back to sleep.

Now, ideally you’re getting the full compliment

of slow wave sleep early in night

and sleep toward morning, which is REM sleep,

which brings us to how to get more REM sleep.

Well, there are a couple of different ways,

but here’s how to not get more REM sleep, all right?

First of all, drink a lot of fluid

right before going to sleep.

One of the reasons why we wake up

in the middle of the night to use the bathroom

is because when our bladder is full,

there is a neural connection,

literally a set of neurons and a nerve circuit

that goes to the brainstem that wakes us up.

And actually some people that I know

and it won’t be mentioned,

actually use this to try and adjust for their jet lag

when they’re trying to stay awake.

Having to use the bathroom,

having to urinate is one of the most anxiety evoking

experiences anyone can have.

If you really have to go to the bathroom,

it’s very hard to fall asleep or stay asleep.

And bedwetting, which happens in kids very early on

is a failure of those circuits to mature until,

you know, I think we all assume that babies

are going to pee in their sleep,

but adults aren’t supposed to do that.

And the circuits take some time to develop

and in some kids they develop a little bit later than others.

So having a full bladder is one way to disrupt your sleep.

You don’t want to go to bed dehydrated, but that’s one way.

On the other hand, there is evidence

that if you want to remember your dreams more

or remember more of your dreams,

there is a tool that you can use.

I don’t necessarily recommend it,

which is to drink a bunch of water before you go to sleep.

And then what happens is you tend to break

in and out of REM sleep.

It tends to be fractured.

And with a sleep journal,

then they’ve done these laboratory studies,

believe it or not, people will recall more of their dreams

because they’re in this kind of semi-conscious state

because they’re constantly waking up throughout the night.

I suggest not having a full bladder before you go to sleep.

That one’s kind of an obvious one, but nonetheless.

The other one is if you recall that during REM sleep,

we have a shift in neurotransmitters

such that we have less serotonin, right?

I just want to make sure I got that right.

Excuse me, less serotonin.

There are a lot of supplements out there

geared toward improving sleep.

I’ve taken some of them and I’ve taken many of them,

if not all of them at this point,

so I could report back to you.

And I think I mentioned on a previous episode

that when I take tryptophan or anything

that contains 5-HTP, which is serotonin

or a precursor to serotonin,

serotonin is made from tryptophan,

I tend to fall very deeply asleep

and then wake up a few hours later.

And that makes sense now based on the fact

that you just don’t want a lot of REM sleep early on.

What was probably happening

is that I was getting a lot of REM sleep early on

because low levels of serotonin

are typically associated with slow-wave sleep

and that comes early in the night.

So for some people, those supplements might work,

but beware serotonin supplements

could disrupt the timing of REM sleep and slow-wave sleep.

And in my case, led to waking up

very shortly after going to sleep

and not being able to get back to sleep.

Now, if you want to increase your slow-wave sleep,

that’s interesting, there are ways to do that.

One of the most powerful ways to increase slow-wave sleep,

the percentage of slow-wave sleep,

apparently without any disruption

to the other components of sleep and learning,

is to engage in resistance exercise.

It’s pretty clear that resistance exercise

triggers a number of metabolic and endocrine pathways

that lend themselves to release of growth hormone,

which happens early in the night.

And resistance exercise, therefore,

can induce a greater percentage of slow-wave sleep.

It doesn’t have to be done very close to going to bedtime.

In fact, for some people,

the exercise could be disruptive

for reasons I’ve talked about in previous episodes.

But resistance exercise, unlike aerobic exercise,

does seem to increase the amount of slow-wave sleep,

which, as we know, is involved in motor learning

and the acquisition of fine detailed information,

not general rules

or the emotional components of experiences.

For those of you that are interested in lucid dreaming

and would like to increase the amount of lucid dreaming

that you’re experiencing,

I haven’t been able to track down that device

with the red light that I described at the beginning,

but there are a number of just simple zero technology tools

that one could use in principle.

One is to set a cue.

The way this works is you come up with a simple statement

about something that you’d like to see

or experience later in dreams.

You can, for instance, write down something like,

I want to remember the red apple.

I know it sounds silly and trivial.

And you look at that,

you would probably want to write it down on a piece of paper.

You might even want to draw a red apple.

And then before you go to sleep, you would look at it.

And then you would just go to sleep.

There are some reports that doing that

for several days in a row can lead to a situation

in which you are suddenly in your dream

and you remember the red apple.

And that gives you a sort of tether to reality

between the dream state and reality

that allows you to navigate and shape

and kind of adjust your dreams.

Lucid dreaming does not have to be

or include the ability to alter features of the dream,

to be able to control things in the dream.

Sometimes it’s just the awareness that you are dreaming,

but nonetheless, some people enjoy lucid dreaming.

And then for people that have a lot of lucid dreams

that feel kind of overwhelmed by those,

that’s going to involve trying to embrace protocols

that can set the right duration of sleep.

There’s a little bit of literature, not a lot,

that shows that keeping the total amount of sleep per night

to say six hours, such that you begin sleep and end

at the beginning and end of one of these ultradian cycles

can be better than waking up

in the middle of one of these ultradian cycles.

So try and find the right amount of sleep that you need,

that’s right for you.

And then try and get that consistently night to night.

If you’re a lucid dreamer and you don’t like it,

then you may want to start to make sure

that you’re waking up at the end

of one of these ultradian cycles.

So in this case, it would be better to wake up

after six hours than after seven.

And if you did sleep longer than six hours,

maybe you’d want to get to seven and a half hours

because that’s going to reflect the end

of one of these 90 minute cycles

as opposed to waking up in the middle.


Alcohol and marijuana are well-known to induce states

that are pseudo sleep-like,

especially when people fall asleep

after having consumed alcohol or THC,

the active component,

one of the active components in marijuana.

Alcohol, THC, and most things like them,

meaning things that increase serotonin or GABA

are going to disrupt the pattern of sleep.

They’re going to disrupt the depth,

they’re going to disrupt the overall sequencing

of more slow-wave sleep early in the night

and more REM sleep later in the night.

That’s just the reality.

There are some things that,

at least in a few studies that I could find,

seem to suggest that you could increase

the amount of slow-wave sleep using things like arginine,

the amino acid arginine,

although you really want to check,

arginine can have effects on heart, et cetera,

has other effects.

But alcohol, THC,

not going to be great for sleep and depth of sleep.

You might feel like you can fall asleep faster,

but the sleep that you’re accessing

really isn’t the kind of deep restorative sleep

that you should be getting.

Now, of course, if that’s what you need in order to sleep,

and that’s within your protocol,

as I’ve said here before,

I’m not suggesting people take anything,

I’m not a medical doctor,

I’m not a cop,

so I’m not trying to regulate anyone’s behavior.

I’m just telling you what the literature says.

Some of you may want to explore your dreams

and meaning of dreams, et cetera.

You know, there’s not a lot of hard data

about how to do this,

but a lot of people report keeping a sleep journal

or a dream journal can be very useful.

So they mark when they think they fell asleep

the night before, when they woke up.

And if they wake up in the middle of the night

or early in the morning,

they’ll just write down what they can recall of their dreams.

And even if they recall nothing,

many people have the experience of mid morning

or later afternoon that suddenly comes to them

that they had a dream about something

and writing that down.

I kept a dream journal for a while.

It didn’t really afford me much.

I didn’t really learn anything

except that my dreams were very bizarre.

But there are some things that happen in dreams

that are associated with REM sleep

as compared to slow wave sleep,

which can tell you whether or not your dream

likely happened in REM sleep or slow wave sleep.

And the distinguishing feature it turns out

is something called theory of mind.

Theory of mind is actually an idea that was developed

for the study and assessment of autism.

And it was initially that phrase theory of mind

was brought about by Simon Baron-Cohen,

who is Sasha Baron-Cohen, the comedian’s brother.

Simon Baron-Cohen is a psychologist

and to some extent a neuroscientist at Oxford.

And theory of mind tests are done on children.

And the theory of mind test is like the following.

A child is brought into a laboratory

and watches a video of a child playing with some sort of toy.

And then at the end of playing with that toy,

they put the toy in a drawer and they go away.

And then another child comes in and is looking around.

And then the experimenter asks the child

who’s in the experiment, the real child,

and says, you know, what does the child think?

You know, what are they feeling?

And most children of a particular age,

five or six or older will say,

oh, you know, he or she is confused.

They don’t know where the toy is.

Or they’ll say something that implies

what we call theory of mind,

that they can put their ideas into,

and their mind into what the other child

is likely to be feeling or experiencing.

That’s theory of mind.

And it turns out that this is used

as one of the assessments for autism

because some children, not all,

but some children that have autism

or that go on to develop autism

don’t have this theory of mind.

They tend to fixate on the fact

that the first child put the toy in the drawer.

They’ll say it’s in the drawer,

as opposed to answering the question,

which is how does the second child feel about it?

Or what are they experiencing?

So theory of mind is something

that emerges early in life

as a part of the maturation of the circuits in the brain

associated with emotional learning and social interactions.

And we experience this in certain dreams.

So if you had a dream that you’re puzzled about

or that you’re fixated on and you’re thinking about,

you might ask, in that dream,

was I assessing somebody else’s emotion and feeling,

or was I very much in my own first-person experience?

And the tendency is that theory of mind

tends to show up most in these REM-associated dreams.

Now, this isn’t a hard and fast rule,

but chances are, if you were in a dream

and you were thinking about other people

who wanted to do something to you,

you were thinking about their desire to chase you

or help you or something that was related

to someone else’s emotional experience,

it was probably a REM dream.

That dream occurred in rapid eye movement sleep

as opposed to slow wave sleep.

And that makes sense when you think about the role of REM

in emotional unlearning of associations

with particular life events,

that REM is rich with all sorts of exploration

of the emotional load of being chased

or the emotional load of having to take an exam the next day

or being late for something.

But again, if you’re fixated

or you can recall thinking a lot about

or feeling a lot about what somebody else’s motivations were

then chances are it was in REM.

And if not, chances are it was in slow wave sleep.

Today, we’ve been in a deep dive of sleep and dreaming,

learning and unlearning.

And I just want to recap a few of the highlights

and important points.

A lot more slow wave sleep and less REM early in the night.

More REM and less slow wave sleep later in the night.

REM sleep is associated with intense experiences

without this chemical epinephrine

that allows us the anxiety or fear

and almost certainly has an important role

in uncoupling of emotion from experiences,

kind of self-induced therapy that we go into each night.

That bears striking resemblance to things like EMDR

and ketamine therapies and so forth.

Slow wave sleep is critical, however.

It’s critical mostly for motor learning

and the learning of specific details.

So REM is kind of emotions and general themes

and meaning and slow wave sleep, motor learning and details.

I personally find it fascinating that consistency of sleep,

meaning getting six hours every night

is better than getting 10 one night,

eight the next, five the next, four the next.

I find that fascinating and I think I also like it

because it’s something I can control better

than just trying to sleep more,

which I think I’m not alone in agreeing

that that’s just hard for a lot of people to do.

This episode also brings us to the conclusion

of a five episode streak where we’ve been focusing on sleep

and transitions in and out of sleep, non-sleep depressed.

We’ve talked about a lot of tools,

morning light, evening light, avoiding lights,

blue blockers, supplements,

tools for measuring sleep duration and quality.

We’ve been covering a lot of themes.

I like to think that by now you’re armed

with a number of tools and information,

things like knowing when your temperature minimum is,

knowing when you might want to view light or not,

when you might want to eat or take hot showers

or God forbid a cold shower,

something that most people, including me,

more or less loathe, but can have certain benefits.

And that will allow you to shape your sleep life

and get this consistent or more or less consistent

amount of sleep on a regular basis.

Nobody’s perfect.

In fact, I have this little joke

that I sometimes tell it’s not funny.

Like most of the jokes I tell, I’m told they’re not funny,

but there’s so much excitement now

about intermittent fasting.

Sometimes I think that someone should start something

on intermittent sleep deprivation,

although we’re already doing that.

We are all experiencing lack of sleep from time to time.

And I don’t think we should catastrophize that too much.

I think that what we want to do

rather than accumulate a sleep anxiety is to,

if we get a bad night’s sleep, we want to adjust.

We want to get back on track

and just get the consistent amount of sleep.

Use those non-sleep deep rest protocols

to help us relax when we’re feeling anxious

or having trouble waking up in the middle of the night.

There are a lot of tools out there

and most of them are zero cost.

And so I hope you’ll find those beneficial.

If you’ve been hearing Costello snoring

throughout this episode, I apologize on his behalf.

As I said in the welcome video to this podcast,

he’s an integral part of the podcast.

A few people have said, hey,

that noise in the background is really disruptive.

Hey, what can I say?

Costello is a 10-year-old bulldog mastiff.

The lifespan on those animals is about 10 years.

So I’m not trying to make you feel guilty,

but after he’s gone, there won’t be any snoring,

although I’ll probably get a different dog.

So sort of a, what would the kids say?

Sorry, not sorry.

Sorry, not sorry about the snoring.

And I’m sorry if it’s disruptive genuinely,

but he’s here for the haul.

So that’s what that’s about.

As we close out this segment on sleep,

we are moving into a new theme and topic

for the next four to five episodes.

We are going to discuss the science

and the tools related to neuroplasticity.

Neuroplasticity is a remarkable feature

of the nervous system.

In fact, it’s the defining feature of the nervous system,

which is its ability to change itself

in response to experience.

That is unlike every other tissue and collection of cells

and organ in our body.

It’s really what makes us us as a species,

and it’s what makes us us as individuals.

And it’s really where our potential lies.

Everything that we know, everything we can do,

and our true potential in terms of what we will ever

be able to know, do, say in life

is set by the limits of neuroplasticity.

So we’re going to explore learning in childhood,

learning in adulthood.

We’re going to discuss detailed protocols

as they relate to sensory plasticity,

learning new sensory information versus motor plasticity

or sensory motor integration.

We’re going to talk about language acquisition.

We’re going to be talking about emotional acquisition

and breadth, as well as I think a topic

a lot of people are going to find fascinating

is the relationship between plasticity set

during childhood attachment to parent or other caregiver

and how that maps onto adult relationships.

You know, there’s many of you have probably heard

about Secure Attach or Insecure Attach,

the A, B and C babies as they’re called

from the classic studies of Bowlby and others.

But now there’s actual neuroscience that can say

which circuits were active during those early life

attachments and how those map to adult attachment styles,

challenges, and what makes us more likely

to select certain partners and styles of attachment,

as well as how to change those.

It’s really fascinating.

And I think neuroscience’s time has come

for neuroplasticity.

We’re also going to talk, of course,

about supplements and chemicals and machines and devices

that can assist in speeding up the plasticity process.

Or believe it or not, there are some cases

where you might want to delay plasticity

in order to get more depth of learning

and have that learning last longer.

Something that is just absolutely spectacular literature.

So I’m very excited to move on to that topic soon.

I hope that the tools that you’ve acquired so far

and the knowledge that you’ve acquired so far

is helping you with your self-evaluation

and experimentation as you see fit,

and is allowing you to not just sleep better,

but feel better while you’re awake,

and hopefully has set the stage for you to learn better

as we start to march into the month on neuroplasticity.

Many of you have asked how you can help support

the Huberman Lab podcast,

and we greatly appreciate the question.

You can help support the podcast

by subscribing to the YouTube channel,

if you haven’t already,

and leaving comments and questions in the comment section.

If you could subscribe on Apple and or Spotify,

that’s helpful.

And there’s a place on Apple podcast to leave a rating

as well as comments about how you feel about the podcast.

If you could suggest the podcast to friends and coworkers

and anyone else that you think would benefit

from the information,

that also really helps us get the word out.

And of course, check out our sponsors

because that’s a very direct way to help us continue

to get this information out to the general public.

And as mentioned at the beginning of today’s episode,

we are now partnered with Momentus Supplements

because they make single ingredient formulations

that are of the absolute highest quality,

and they ship international.

If you go to slash Huberman,

you will find many of the supplements

that have been discussed on various episodes

of the Huberman Lab podcast,

and you will find various protocols

related to those supplements.

Last but not least,

a few people wrote to me with some questions

slash corrections about things that I said

in previous podcasts.

So in keeping with my goal

of making the information accurate and clear,

I just want to correct myself

about a few things that I said.

One of those,

and I’m guessing it probably came from an endocrinologist

or somebody else that knows a lot about testicles,

said, Huberman, you mentioned that testosterone

is made by the sertoli cells of the testes,

and it’s not.

It’s made by the Leydig cells of the testes,

and indeed you are correct.

And so I want to make sure that I clarify that.

Testosterone is made by the Leydig cells of the testes,

not by the sertoli cells.

The sertoli cells make 5-alpha reductase and aromatase

and some other enzymes involved in conversion of testosterone

into things like DHT and estrogen.

So thank you for that correction.

I genuinely appreciate it.

I misspoke.

The other thing I said was at one point I said,

typical temperature is 96.8,

when I actually meant to say 98.6.

So it was a dyslexic slip on my part,

and I apologize.

I don’t know that I’m dyslexic.

I know I’ve been clinically diagnosed with dyslexia,

but I swapped them,

which sometimes happens when I’m going fast.

So I apologize.

I’ll use this as a moment to just say,

temperature varies a lot across the day and night.

That was a theme of previous podcasts.

So we can’t really talk about average temperature anyway,

but I do want to be clear that most people think

about average temperature as 98.6.

I misspoke my error and I apologize.

Thank you for joining me in this journey

of the nervous system and biology

and trying to understand the mechanisms

that make us who we are and how we function

in sleep and in wakefulness.

It’s really an incredible landscape to consider.

And I hope that you’re getting a lot out of the information.

As always, thank you for your interest in science.