ANDREW HUBERMAN: Welcome
to Huberman Lab Essentials, where we revisit past
episodes for the most potent and actionable
science-based tools for mental health, physical
health, and performance. [MUSIC PLAYING] My name is Andrew
Huberman, and I'm a professor of neurobiology
and ophthalmology at Stanford School of Medicine. Today we're talking
about neuroplasticity, which is this incredible feature
of our nervous system's that allows it to change in
response to experience. Neuroplasticity is arguably one
of the most important aspects of our biology. It holds the promise
for each and all of us to think differently,
to learn new things, to forget painful experiences,
and to essentially adapt to anything that life
brings us by becoming better. So let's get started. Most people are familiar with
the word "neuroplasticity," which is the brain and nervous
system's ability to change itself. All of us were born
with a nervous system that isn't just
capable of change but was designed to change. When we enter the world,
our nervous system is primed for learning. The brain and nervous system of
a baby is wired very crudely. The connections are
not precise, and we can see evidence
of that in the fact that babies are kind of flopping
there, like a little potato bug with limbs. They can't really do much in
terms of coordinated movement. They certainly can't speak,
and they can't really do anything with precision. So I want you to
imagine in your mind that when you were
brought into this world, you were essentially a widely
connected web of connections that was really poor
at doing any one thing, and that through your
experience, what you were exposed to by your parents
or other caretakers, through your social
interactions, through your thoughts, through
the languages that you learned, through the places you
traveled or didn't travel, your nervous system
became customized to your unique experience. Now, that's true for
certain parts of your brain that are involved in what
we call representations of the outside world. A lot of your brain is designed
to represent the visual world, or represent the auditory
world, or represent the gallery of smells that
are possible in the world. However, there are aspects
of your nervous system that were designed
not to be plastic. They were wired so that
plasticity or changes in those circuits
is very unlikely. Those circuits include
things like the ones that control your heartbeat. The ones that control
your breathing. The ones that control
your digestion. And thank goodness that
those circuits were set up that way, because you want
those circuits to be extremely reliable. So many nervous system features,
like digestion and breathing and heart rate,
are hard to change. Other aspects of
our nervous system are actually quite
easy to change. And one of the great gifts
of childhood, adolescence, and young adulthood is that
we can learn through almost passive experience. We don't have to focus that hard
in order to learn new things. And then after
age 25, if we want to change those connections,
those superhighways of connectivity, we have to
engage in some very specific processes. And those processes,
as we'll soon learn, are gated, meaning
you can't just decide to change your brain. You actually have to go
through a series of steps to change your internal
state in ways that will allow you to change your brain. Many of us have been
captivated by the stories in the popular press about
the addition of new neurons, this idea, oh, if you go
running or you exercise, your brain actually
makes new neurons. Well, I'm going to give
you the bad news, which is that after puberty, the
human brain and nervous system adds very few, if
any, new neurons. So even though we can't add new
neurons throughout our lifespan, at least not in
very great numbers, it's clear that we can
change our nervous system, that the nervous system
is available for change, that if we create the
right set of circumstances in our brain, chemical
circumstances, and if we create the right
environmental circumstances around us, our
nervous system will shift into a mode in which
change isn't just possible, but it's probable. As I mentioned
before, the hallmark of the child nervous
system is change. It wants to change. One of the ways in which
we can all get plasticity at any stage
throughout the lifespan is through deficits
and impairments in what we call our sensory
apparati-- our eyes, our ears, our nose, our mouth. In individuals that
are blind from birth, the so-called occipital cortex,
the visual cortex in the back, becomes overtaken by hearing. The neurons there will start
to respond to sounds as well as Braille touch. And actually, there is one
particularly tragic incident where a woman who
was blind since birth and, because of
neuroimaging studies, we knew her visual cortex
was no longer visual. It was responsible for Braille
reading and for hearing. She had a stroke that
actually took out most of the function
of her visual cortex. So then she was blind, she
couldn't Braille read, or hear. She did recover some
aspect of function. Now, most people, they don't end
up in that highly unfortunate situation. And what we know is that, for
instance, blind people who use their visual cortex for
Braille reading and for hearing have much better
auditory acuity and touch acuity, meaning they can sense
things with their fingers and they can sense
things with their hearing that typical sighted
folks wouldn't be able to. In fact, you will find
a much greater incidence of perfect pitch in
people that are blind. And that tells us that the brain
and, in particular, this area we call the neocortex,
which is the outer part, is really designed to be a
map of our own individual experience. So these, what I
call experiments of impairment or
loss, where somebody is blind from birth
or deaf from birth or maybe has a limb development
impairment where they have a stump instead of an entire
limb with a functioning hand, their brain will represent the
body plan that they have, not some other body plan. But the beauty of the situation
is that the real estate up in the skull, that
neocortex, the essence of it is to be a customized
map of experience. A few years ago,
I was at a course, and a woman came up to me
and she said, you know, I-- I wasn't teaching the course. I was in the course. And she said, I just
have to tell you that every time you speak,
it really stresses me out. And I said, well, I've
heard that before. But do you want to
be more specific? And she said, yeah,
your tone of voice reminds me of somebody that I
had a really terrible experience with. I said, well, OK, well,
I can't change my voice, but I really appreciate
that you acknowledge that. And it also will
help explain why you seem to cringe
every time I speak, which I hadn't
noticed until then. But after that, I
did notice she had a very immediate and kind of
visceral response to my speech. But in any event, over the
period of this two-week course, she would come back every
once in a while and say, you know what? I think just by telling you that
your voice was really difficult for me to listen
to, it's actually becoming more tolerable to me. And by the end, we actually
became pretty good friends, and we're still in touch. And so what this says is that
the recognition of something, whether or not that's an
emotional thing or a desire to learn something else,
is actually the first step in neuroplasticity. If I get up out of this chair
and walk out of the door, I don't think about each
step that I'm taking. And that's because I learned
how to walk during development. But when we decide
that we're going to shift some sort of
behavior or some reaction or some new piece of information
that we want to learn is something that we want to
bring into our consciousness, that awareness is
a remarkable thing because it cues the brain and
the rest of the nervous system that when we engage in those
reflexive actions going forward, that those reflexive actions are
no longer fated to be reflexive. Now, if this sounds a
little bit abstract, we're going to talk about
protocols for how to do this. But the first step
in neuroplasticity is recognizing that you
want to change something. We have to know what it is
exactly that we want to change. Or if we don't know exactly what
it is that we want to change, we at least have to know that
we want to change something about some specific experience. Now, there are
specific protocols that science tells us
we have to follow if we want those changes to occur. What it is, is
it's our forebrain, in particular our
prefrontal cortex, signaling the rest
of our nervous system that something that we're about
to do, hear, feel, or experience is worth paying attention to. So we'll pause there, and then
I'm going to move forward. One of the biggest lies
in the universe that seems quite prominent right now
is that every experience you have changes your brain. People love to say this. They love to say,
your brain is going to be different
after this lecture, or your brain is going to be
different after today's class than it was two days ago. And that's absolutely not true. The nervous system
doesn't just change because you experience
something unless you're a very young child. The nervous system changes
when certain neurochemicals are released and
allow whatever neurons are active in the period in
which those chemicals are swimming around to
strengthen or weaken the connections
of those neurons. So when people tell you, oh,
at the end of today's lecture, at the end of
something, your brain is going to be completely
different, that's simply not true. If you're older
than 25, your brain will not change unless
there's a selective shift in your attention or a selective
shift in your experience that tells the brain
it's time to change. And those changes occur through
strengthening and weakening of particular connections. But the important
thing to understand is that if we want
something to change, we really need to bring an
immense amount of attention to whatever it is that
we want to change. This is very much
linked to the statement I made earlier about it all
starts with an awareness. Now, why is that
attention important? In the early '90s, a graduate
student by the name of Gregg Recanzone was in the laboratory
of a guy named Mike Merzenich at UCSF. And they set out
to test this idea that if one wants to
change their brain, they need to do it early in life
because the adult brain simply isn't plastic. It's not available
for these changes. And they did a series
of absolutely beautiful experiments, by
now, I think we can say proving that the
adult brain can change, provided certain
conditions are met. Now, the experiments
they did are tough. They were tough on
the experimenter, and they were tough
on the subject. I'll just describe one. Let's say you were a subject
in one of their experiments. You would come into the lab,
and you'd sit down at a table, and they would record
from or image your brain and look at the representation
of your fingers, the digits, as we call them. And there would be a spinning
drum, literally like a stone drum in front of you, or metal
drum, that had little bumps. Some of the bumps were spaced
close together, some of them were spaced far apart. And they would do
these experiments where they would
expect their subjects to press a lever whenever, for
instance, the bumps got closer together or further apart. And these were very
subtle differences. So in order to do
this, you really have to pay attention to the
distance between the bumps. And these were not
Braille readers or anyone skilled in doing these
kinds of experiments. What they found
was that as people paid more and more
attention to the distance between these bumps-- and they would
signal when there was a change by pressing a lever. As they did that, there
was very rapid changes, plasticity in the
representation of the fingers. And it could go in
either direction. You could get people
very good at detecting the distance between bumps that
the distance was getting smaller or the distance was
getting greater. So people could get very
good at these tasks that are kind of hard
to imagine how they would translate to the real
world for a non-Braille reader. But what it told us is
that these maps of touch were very much available
for plasticity, and these were fully
adult subjects. What it proved is that the
adult brain is very plastic. And they did some beautiful
control experiments that are important for
everyone to understand, which is that sometimes
they would bring people in and they would have
them touch these bumps on this spinning drum, but
they would have the person pay attention to an auditory cue. Every time a tone
would go off or there was a shift in the
pitch of that tone, they would have to signal that. So the subject thought
they were doing something related to touch and hearing. And all that showed
was that it wasn't just the mere action of
touching these bumps; they had to pay attention
to the bumps themselves. If they were placing their
attention on the auditory cue, on the tone, well,
then there was plasticity in the auditory
portion of the brain, but not on the touch
portion of the brain. And this really spits in
the face of this thing that you hear so often,
which is, every experience that you have is going to
change the way your brain works. Absolutely not. The experiences that you pay
super careful attention to are what open up plasticity,
and it opens up plasticity to that specific experience. So the question then is, why? And Merzenich and his
graduate students and postdocs went on to address
this question of why. And it turns out, the answer
is a very straightforward neurochemical answer. And the first neurochemical is
epinephrine, also adrenaline. We call it adrenaline when it's
released from the adrenal glands above our kidneys. That's in the body. We call it epinephrine
in the brain, but they are chemically
identical substances. Epinephrine is released from a
region in the brainstem called locus ceruleus. Epinephrine is released
when we pay attention and when we are alert. But the most important
thing for getting plasticity is that there be
epinephrine, which equates to alertness, plus the
release of this neuromodulator acetylcholine. Now, acetylcholine is released
from two sites in the brain. One is also in the brainstem,
and it's named different things in different animals. But in humans, the most rich
site of acetylcholine neurons, or neurons that
make acetylcholine, is the parabigeminal nucleus
or the parabrachial region. All you need to know is that you
have an area in your brainstem, and that area sends wires,
these axons, up into the area of the brain that
filters sensory input. So we have this area of the
brain called the thalamus, and it is getting bombarded
with all sorts of sensory input all the time. But when I pay
attention to something, I create a cone of attention,
and what we call signal to noise goes up. So those of you with an
engineering background will be familiar
with signal to noise. Those of you who do not have
an engineering background, don't worry about it. All it means is that one
particular shout in the crowd comes through. Acetylcholine acts
as a spotlight. But epinephrine for alertness,
acetylcholine spotlighting these inputs, those
two things alone are not enough to
get plasticity. There needs to be
this third component, and the third component
is acetylcholine released from an area
of the forebrain called nucleus basalis. If you really want
to get technical, it's called nucleus
basalis of Meynert. For any of you that are
budding physicians or going to medical school,
you should know that. If you have acetylcholine
released from the brainstem, acetylcholine released
from nucleus basalis, and epinephrine, you
can change your brain. And this has been shown
again and again and again in a variety of
papers, and it is now considered a fundamental
principle of how the nervous system works. If you can access these
three things of epinephrine, acetylcholine from
these two sources, not only will the nervous
system change, it has to change. It absolutely will change. And that is the
most important thing for people to understand if
they want to change their brain. So now let's talk about
how we would translate all this scientific
information into some protocols that you can actually apply
because I think that's what many of you are interested in. What you do with your health and
your medical care is up to you. You're responsible for
your health and well-being. So I'm not going to tell you
what to do or what to take, I'm going to describe what the
literature tells us and suggests about ways to access plasticity. We know we need epinephrine. That means alertness. Most people accomplish this
through a cup of coffee and a good night's sleep. So I will say you should
master your sleep schedule, and you should figure out how
much sleep you need in order to achieve alertness when
you sit down to learn. But once that's in
place, the question then is, how do I
access this alertness? Well, there are
a number of ways. Some people use some pretty
elaborate psychological gymnastics. They will tell
people that they're going to do something and
create some accountability. That could be really good. Or they'll post a picture
of themselves online, and they'll commit to
learning a certain amount-- losing, excuse me, a certain
amount of weight or something like this. So they can use either
shame-based practices to potentially
embarrass themselves if they don't follow through. They'll write checks
to organizations that they hate and
insist that they'll cash them if they don't
actually follow through. Or they'll do it out of love. They'll decide that they're
going to run a marathon or learn a language or something
because of somebody they love, or they want to
devote it to somebody. The truth is that from the
standpoint of epinephrine and getting alert and activated,
it doesn't really matter. Epinephrine is a
chemical, and your brain does not distinguish
between doing things out of love or hate, anger, or fear. It really doesn't. All of those promote
autonomic arousal and the release of epinephrine. So I think for most
people, if you're feeling not motivated to make
these changes, the key thing is to identify not just one, but
probably a kit of reasons, several reasons as
to why you would want to make this particular change. And being drawn toward
a particular goal that you're excited
about can be one. Also being motivated to not
be completely afraid, ashamed, or humiliated for not following
through on a goal is another. Come up with two
or three things, fear-based, perhaps, love-based,
perhaps, or perhaps several of those in order to ensure
alertness, energy, and attention for the task. And that brings us to
the attention part. Now, it's one thing to
have an electrode embedded into your brain and increase
the amount of acetylcholine. It's another to exist
in the real world outside the laboratory and have
trouble focusing, having trouble bringing your attention to a
particular location in space for a particular event. And there's a lot of discussion
nowadays about smartphones and devices creating a
sort of attention deficit, almost at a clinical level for
many people, including adults. I think that's largely true. And what it means,
however, is that we all are responsible for learning
how to create depth of focus. There are some important
neuroscience principles to get depth of focus. I want to briefly talk
about the pharmacology first because I always get
asked about this. People say, what can
I take to increase my levels of acetylcholine? Well, there are
things you can take. Nicotine is called nicotine
because acetylcholine binds to the nicotinic receptor. There are two kinds of
acetylcholine receptors, muscarinic and nicotinic. But the nicotinic
ones are involved in attention and alertness. I have colleagues-- these are
not my kind of like bro science buddies. I have those friends, too. This is a Nobel
Prize-winning colleague who chews Nicorette while he works. But when I asked him,
why are you doing this, he said, well, it increases
my alertness and focus. Now, I've tried
chewing Nicorette. It makes me super jittery. I don't like it because
I can't focus very well. It kind of takes me too far up
the level of autonomic arousal. I've got friends that
dip Nicorette all day. If you're going to
go down that route, you want to be very
careful how much you rely on those all the time because
the essence of plasticity is to create a window
of attention and focus that's distinct from
the rest of your day. So what are some ways that you
can increase acetylcholine? How do you increase focus? The best way to get
better at focusing is to use the mechanisms of
focus that you were born with. And the key principle
here is that mental focus follows visual focus. We are all familiar
with the fact that our visual system can be
unfocused, blurry, or jumping around, or we can be
very laser-focused on one location in space. What's interesting and vitally
important to understanding how to access
neuroplasticity is that you can use your visual
focus, and you can increase your
visual focus as a way of increasing your mental
focus abilities more broadly. So I'm going to
explain how to do that. Plasticity starts
with alertness. That alertness can come from a
sense of love, a sense of joy, a sense of fear. Doesn't matter. There are pharmacologic ways
to access alertness, too. The most common one is,
of course, caffeine. Many people are now
also using Adderall. Adderall will not
increase focus. It increases alertness. It does not touch the
acetylcholine system. The acetylcholine system
and the focus that it brings is available, as I mentioned,
through pharmacology, but also through these
behavioral practices. And the behavioral
practices that are anchored in
visual focus are going to be the ones that are going to
allow you to develop great depth and duration of focus. So let's think about
visual focus for a second. When we focus on something
visually, we have two options. We can either look at a
very small region of space with a lot of detail
and a lot of precision, or we can dilate
our gaze and we can see big pieces of visual
space with very little detail. It's a trade-off. We can't look at everything
at high resolution. This is why we have these. The pupil more or less
relates to the fovea of the eye, which is the area
in which we have the most receptors, the highest
density of receptors that perceive light. And so our acuity is
much better in the center of our visual field
than in our periphery. When we focus our eyes,
we do a couple of things. First of all, we tend
to do that in the center of our visual field,
and our two eyes tend to align in what's
called a vergence eye movement towards a common point. The other thing that happens
is the lens of our eye moves, so that our brain,
now, no longer sees the entire visual
world, but is seeing a small cone of visual imagery. That small cone
of visual imagery, or soda straw view of the world,
has much higher acuity, higher resolution, than if I were
to look at everything. Now you say, of course,
this makes perfect sense. But that's about visual
attention, not mental attention. Well, it turns out
that focus in the brain is anchored to
our visual system. I'll talk about blind
people in a moment. But assuming that
somebody is sighted, the key is to learn how to
focus better visually if you want to bring about higher
levels of cognitive or mental focus. When we move our eyes
slightly inward-- maybe you can tell that I'm
doing this-- like so, basically shortening or making the
interpupillary distance, as it's called, smaller,
two things happen. Not only do we develop a smaller
visual window into the world, but we activate a set
of neurons in our brain stem that trigger the release
of both norepinephrine, epinephrine, and acetylcholine. Norepinephrine is kind of
similar to epinephrine. So in other words,
when our eyes are relaxed in our head,
when we're just kind of looking at our
entire visual environment, moving our head around,
moving through space, we're in optic flow,
things moving past us, we're sitting still, we're
looking broadly at our space, we're relaxed. When our eyes move
slightly inward toward a particular
visual target, our visual world shrinks, our
level of visual focus goes up, and we know that this relates
to the release of acetylcholine and epinephrine at
the relevant sites in the brain for plasticity. Now, what this means is that if
you have a hard time focusing your mind for sake of
reading or for listening, you need to practice--
and you can practice-- focusing your visual system. Now, this works
best if you practice focusing your visual system
at the precise distance from the work that you intend
to do for sake of plasticity. So how would this look
in the real world? Let's say I am trying to
concentrate on something related to, I don't know, science. I'm reading a science paper
and I'm having a hard time. It's not absorbing. Spending just 60 to 120 seconds
focusing my visual attention on a small window of my screen,
meaning just on my screen with nothing on it,
but bringing my eyes to that particular
location increases not just my visual acuity
for that location, but it brings about an
increase in activity in a bunch of other
brain areas that are associated with gathering
information from this location. So, put simply, if you want to
improve your ability to focus, practice visual focus. Now, you may ask, well,
what about the experiment where people were feeling
this rotating drum or listening to
the auditory cue? That does involve vision at all. Ah. If you look at people
who are learning things with their auditory system, they
will often close their eyes. And that's not a coincidence. If somebody is
listening very hard, please don't ask them to
look you directly in the eye while also asking that
they listen to you. That's actually one
of the worst ways to get somebody
to listen to you. If you say, now listen to
me and look me in the eye, the visual system will take over
and they'll see your mouth move, but they're going to hear their
thoughts more than they're going to hear what you're saying. Closing the eyes is
one of the best ways to create a cone of
auditory attention. And this is what low-vision
or no-vision folks do. They have tremendous capacity
to focus their attention in particular locations. And for most people,
vision is the primary way to train up this focus ability
and these cones of attention. So you absolutely have
to focus on the thing that you're trying
to learn, and you will feel some agitation
because of the epinephrine in your system. If you're feeling agitation
and it's challenging to focus and you're feeling like
you're not doing it right, chances are you're
doing it right. So once you get this
epinephrine, this alertness, you get the acetylcholine
released and you can focus your attention, then
the question is, for how long? And in an earlier
podcast, I talked about these ultradian cycles
that last about 90 minutes. The typical learning bout
should be about 90 minutes. I think that learning bout will
no doubt include 5 to 10 minutes of a warm-up period. I think everyone
should give themselves permission to not
be fully focused in the early part of that
bout, but that in the middle of that bout for the
middle hour or so, you should be able to maintain
focus for about an hour or so. So that, for me, means
eliminating distractions. That means turning
off the Wi-Fi. I put my phone in
the other room. I encourage you to
try experiencing what it is to be completely
immersed in an activity where you feel the agitation
that your attention is drifting, but you continually
bring it back. And that's an important point,
which is that attention drifts, but we have to re-anchor it. We have to keep
grabbing it back. And the way to do that,
if you're sighted, is with your eyes, that as your
attention drifts and you look away, you want to
try and literally maintain visual
focus on the thing that you're trying to learn. That's the trigger
for plasticity. But the real secret is
that neuroplasticity doesn't occur
during wakefulness, it occurs during sleep. We now know that if you
focus very hard on something for about 90 minutes
or so, maybe you even do several bouts
of that per day, if you can do that--
some people can. Some people can only do one
focus bout of learning-- that night and the following
nights while you sleep, the neural circuits that were
highlighted, if you will, with acetylcholine
transmission, will strengthen. And other ones
will be lost, which is wonderful because that's
the essence of plasticity. And what it means is
that when you eventually wake up a couple of
days or a week later, you will have acquired
the knowledge forever, unless you go through some
process to actively unlearn it. So mastering sleep
is key in order to reinforce the
learning that occurs. But let's say you get a
really poor night of sleep after a bout of learning. Chances are, if you sleep the
next night or the following night, that learning will occur. There's a stamp in the brain
where this acetylcholine was released. It actually marks those
synapses neurochemically and metabolically so that
those synapses are more biased to change. Now, if you don't ever
get that deep sleep, then you probably won't
get those changes. There is also a way
in which you can bypass the need for
deep sleep, at least partially, by engaging in what
I call non-sleep deep rest, these NSDR protocols. But I just want to discuss
the science of this. There was a paper
that was published in Cell Reports last year that
shows that if people did-- it was a spatial memory task,
actually quite difficult one, where they had to remember the
sequence of lights lighting up. And if there were just
two or three lights in a particular
sequence, it's easy. But as you get up to 15
or 16 lights and numbers in the sequence, it actually
gets quite challenging. If immediately after-- and
it was immediately after the learning, the actual
performance of this task, people took a 20-minute
non-sleep deep-rest protocol or took a shallow nap, so lying
down, feet slightly elevated, perhaps, just closing their
eyes, no sensory input, the rates of learning were
significantly higher for that information than were they to
just had a good night's sleep the following night. So you can actually
accelerate learning with these NSDR protocols or
with brief naps, 90 minutes or less. For many people,
letting the mind drift, where it's not
organized in thought, after a period of very
deliberate, focused effort, is the best way to accelerate
learning and depth of learning. I want to synthesize
some of the information that we've covered up until now. Today, I want to make sure
that these key elements that form the backbone
of neuroplasticity are really embedded
in people's minds. First of all, plasticity
occurs throughout the lifespan. If you want to learn as an
adult, you have to be alert. It might seem so obvious,
but I think a lot of people don't think about when in their
24-hour cycle they're most alert. Just ask yourself
when during the day do you typically tend
to be most alert? That will afford
you an advantage in learning specific things
during that period of time. So don't give up
that period of time for things that are meaningless,
useless, or not aligned with your goals. That epinephrine released
from your brain stem is going to occur more readily
at particular phases of your 24-hour
cycle than others-- during the waking
phase, of course. You should know when those are. Increasing acetylcholine can be
accomplished pharmacologically through nicotine. However, there are certain
dangers for many people to do that, as well as a cost. financial cost. Learning how to engage
the cholinergic system through the use of
the visual system. Practicing; how long
can you maintain focus with blinks as you need them. But how long can you maintain
visual focus on a target, just on a piece of paper set
a few feet away in the room, or at the level of
your computer screen. These are actually
things that people do in communities where
high levels of visual focus are necessary. What we're really
talking about here is trying to harness the
mechanisms of attention and get better at
paying attention. You may want to do that with
your auditory system, not with your visual system,
either because you're low-vision or no-vision,
or because you're trying to learn something
that relates more to sounds. You should also ask
yourself whether or not you're trying to focus too much
for too long during the day. I know some very
high-performing individuals, very high-performing in
a variety of contexts, and none of them are
focused all day long. Many of them take
walks down the hallway, sometimes mumbling to themselves
or not paying attention to anything else. They go for bike
rides, they take walks. They are not trying to engage
their mind at maximum focus all the time. Very few people do that because
we learn best in these 90-minute bouts inside of one of
these ultradian cycles. And I should repeat again that
within that 90-minute cycle, you should not expect yourself
to focus for the entire period of one 90-minute cycle. The beginning and end are
going to be a little bit flickering in and out of focus. How do you know when one of
these 90-minute cycles is starting? Well, typically when you wake
up is the beginning of the first 90-minute cycle, but it's
not down to the minute. You'll be able to tap into your
sense of these 90-minute cycles as you start to engage in
these learning practices, should you choose. And then, of course, getting
some non-sleep deep rest or just deliberate
disengagement, such as walking or
running or just sitting, eyes closed or eyes open, kind
of mindlessly, it might seem, in a chair. Just letting your
thoughts move around after a learning
bout will accelerate the rate of plasticity. And then, of course, deep sleep. Many of you have
very graciously asked how you can help support
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interest in science. [MUSIC PLAYING]