This episode introduces neuroplasticity—which is how our brain and
nervous system learn and acquire new capabilities. I describe the
differences between childhood and adult neuroplasticity, the chemicals
involved and how anyone can increase their rate and depth of learning
by leveraging the science of focus. I describe specific tools for
increasing focus and learning. The next two episodes will cover the
ideal protocols for specific types of learning and how to make
learning new information more reflexive.
-- Welcome to the Huberman Lab Podcast where we discuss science and
science-based tools for everyday life. [upbeat music] My name is
Andrew Huberman and I'm a professor of Neurobiology and Ophthalmology
at Stanford school of medicine. This podcast is separate from my
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Today we're talking about neuroplasticity which is this incredible
feature of our nervous systems 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. Neuroplasticity has a long and important history and we're not
going to review all of it in detail. But today what we are going to do
is discuss what is neuroplasticity? As well as the different forms of
neuroplasticity. We're going to talk about how to access
neuroplasticity depending on how old you are and depending on the
specific types of changes that you're trying to create. This is a
topic for which there are lots of tools, as well as lots of biological
principles that we can discuss. So let's get started. Most people are
familiar with the word neuroplasticity. It's sometimes also called
neural plasticity. Those are the same thing. So, if I say
neuroplasticity or neural plasticity, I'm referring to the same
process, which is the brain and nervous system's ability to change
itself. There are a lot of reasons why the nervous system would do
this. It could do it in response to some traumatic event. It could,
for instance, create a sense of fear around a particular place or a
fear of automobiles or planes. It could also occur when something
positive happens, like the birth of our first child or when our puppy
does something amusing or we see an incredible feat of performance in
athleticism. The word neuroplasticity means so many things to so many
different people that I thought it would be important to just first
put a little bit of organizational logic around what it is and how it
happens, because nowadays if you were to go online and Google the word
neuroplasticity, you would find hundreds of thousands of references,
scientific references as well as a lot of falsehoods about what
neuroplasticity is and how to access it. As I mentioned before, we're
going to talk about the science of it and we're going to talk about
the tools that allow you to engage this incredible feature of your
nervous system. And that's the first point, which is that 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, they're 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. And that's because we come into this world
overconnected. We have essentially wires, those wires have names like
axons and dendrites. Those are the different parts of the neurons
discussed in episode one, but those little parts and those wires and
connections are everywhere. Imagine a bunch of roads that are all
connected to one another in kind of a mess, but there are no highways.
They're all just small roads. That's essentially what the young
nervous system is like. And then as we mature, as we go from day one
of life to 10 years old, 20 years old, 30 years old, what happens is
particular connections get reinforced and stronger and other
connections are lost. So that's the first important principle that I
want everyone to understand, which is that developmental plasticity,
the neuroplasticity that occurs from the time we're born until about
age 25 is mainly a process of removing connections that don't serve
our goals well. Now, of course, certain events happen during that
birth to 25 period in which positive events and negative events are
really stamped down into our nervous system in a very dramatic
fashion, by what we call one-trial learning.
We experience something once and then our nervous system is forever
changed by that experience. Unless of course, we go through some work
to undo that experience. 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 rather caretakers, through your social interactions,
through your thoughts, through the languages that you learn, 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. You never
want to have to think about whether or not your heart will beat or
whether or not you will continue breathing or whether or not you'll be
able to digest your food. 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. In fact, children go
from being able to speak no language whatsoever to being able to speak
many many words and comprise sentences including words they've never
heard before which is remarkable. It means that the portions of the
brain involved in speech and language are actually primed to learn and
create new combinations. What this tells us is that the young brain is
a plasticity machine. But then right about age 25 plus or minus a year
or two, everything changes.
After age 25 or so, in order to get changes in our nervous system, we
have to engage in a completely different set of processes in order to
get those changes to occur and for them more importantly to stick
around. And this is something that I think is vastly overlooked in the
popular culture discussion about neuroplasticity. People always talk
about fire together, wire together. Fire together wire together is
true. It is the statement of my colleague at Stanford, Carla Shatz and
it's an absolute truth about the way that the nervous system wires up
early in development. But, fire together wire together doesn't apply
in the same way after age 25. And so we have these little memes and
these little quotes that, you know circulate on the internet like fire
together, wire together or there's a famous quote from the greatest
neurobiologist of all time, Ramón y Cajal. I think it goes something
like, you know should somebody wish to change their nervous system
they could be the sculptor of their nervous system in any way they
want, something like that. And that sounds great. I mean, who wouldn't
want to change their nervous system any way they want, but what's lost
in those statements is how to actually accomplish that. And we're
going to cover that today but please understand that early in
development your nervous system is connected very broadly in ways that
make it very hard to do anything well. From birth until about age 25
those connections get refined mainly through the removal of
connections that don't serve us and the incredible strengthening of
connections that relate to either powerful experiences or that allow
us to do things like walk and talk and do math, et cetera. And then
after age 25, if we want to change those connections, those super
highways 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.
I just want to acknowledge that Costello is snoring particularly loud
today. Some of you seem very keen at picking up on his snoring, others
of you can't hear his snoring. It's very low rumbling sound and
whether or not you can or you can't probably relates to the
sensitivity of your hearing. We're actually going to talk about
perfect pitch today and range of auditory detection. And so if you can
hear Costello's snoring enjoy, if you can't, enjoy. I want to talk
about how the nervous system changes. What are these changes? 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 first
which is that, after puberty, so after about age 14 or 15, the human
brain and nervous system adds very few if any new neurons. The idea
that new neurons could be added to the brain is one that has a rich
history in experimental science. It's clear that in rodents and in
some non-human primates new neurons, a process called neurogenesis,
can occur in areas of the brain, such as the olfactory bulb, which is
of course involved in smell as well as a region of our hippocampus, a
center of the brain involved in memory called the dentate gyrus of the
hippocampus. And there is strong evidence that new neurons can be
added to those structures throughout the lifespan. In humans, the
evidence is a little bit more controversial. It's clear that we can
add new neurons to our olfactory bulb. In fact, if any of you have
ever had the unfortunate experience of being hit on the head too hard,
the wires called axons from those olfactory neurons that live in your
nose can get sheared off because they have to pass through a bony
plate called the cribriform plate.
And the cribriform plate can shear those axons and people can become
what's called anosmic, they won't be able to smell. But over time,
those neurons unlike most all central nervous system neurons can grow
those connections back and even reestablish new neurons being added to
the olfactory bulb. They come from elsewhere deep in the brain and
they migrate through a pathway called the rostral migratory stream.
You can Google these words and look up some of the descriptions of
this if you'd like to learn more. So indeed there is some evidence
that the neurons responsible for smell can be replaced throughout the
lifespan. Certainly, in very young individuals from birth till about
age 15 or so. Whether or not they're new neurons added to the
hippocampus, the memory center of the human brain isn't clear. Many
years ago, Rusty Gage's lab at the Salk Institute did a really
important study looking at terminally ill cancer patients and
injecting them with a label, a dye that is incorporated only into new
neurons.
And after these patients died, their brains were harvested. The brains
were looked at and there were new neurons there, there was evidence
for new neurons. Those results I think stand over time but what was
not really discussed in the popular press discussion around those
papers was that it was very few cells that were being added. And a
number of papers have come along over the years mainly from labs at
UCSF, although from others as well, showing that if there are new
neurons added to the adult brain, it's an infinitesimally small number
of new neurons. So that's the depressing part, we don't get new
neurons. After we're born, we pretty much have the neurons that we're
going to use our entire life. And yes, as we get older and we start to
lose certain functions in our brain, we lose neurons. But all is not
lost, so to speak, because there are other ways in which neurocircuits
can create new connections and add new functions including new memory,
new abilities and new cognitive functions. And those are mainly
through the process of making certain connections, which of course are
those things we call synapses, between neurons making those
connections stronger. So they're more reliable, they're more likely to
engage as well as removing connections. And the removal of connections
is vital to say moving through a grieving process or removing the
emotional load of a traumatic experience.
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.
The whole thing, everything from the chemicals that are sloshing
around in there to the fact that there's a lot of space between the
neurons. A lot of people don't know this, but early in development
there's a lot of space between the neurons. And so the neurons can
literally move around and sample different connections very easily
removing some and keeping others. As we get older, the so-called
extracellular space is actually filled up by things called
extracellular matrix and glial cells. Glial means glue. Those cells
are involved in a bunch of different processes but they start to fill
in all the space kind of like pouring concrete between rocks. And when
that happens, it becomes much harder to change the connections that
are there. 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, and there are some very dramatic and somewhat tragic examples
of people, for instance who have genetic mutations where they're born
without a nose and without any olfactory structures in the brain so
they cannot smell.
In that case areas of the brain that normally would represent smell
become overtaken by areas of the brain involved in other things like
touch and hearing and sight. 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's a 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. Now, it is true however, that if let's say I were to be
blind when I'm 50, I'm 45 right now, I've always been sighted. If I
was blind at 50, I'll probably have less opportunity to use my
formerly visual cortex for things like braille reading and hearing
because my brain has changed, it's just not the same brain I had when
I was a baby. So there's actually a principle of biology, not many
people know this, it's actually a principle neurology which is called
the Kennard principle, which says, if you're going to have a brain
injury, you want to have it early in life.
And of course better to not have a brain injury at all but if you're
going to have it you want to have it early in life. And this is based
on a tremendous number of experiments examining the amount of recovery
and the rate of recovery in humans that had lesions to their brain
either early in life or later in life. So the Kennard Principle says
better to have injuries early in life. Now, that's reassuring for the
young folks, it's not so reassuring for the older folks. But there are
aspects of neuroplasticity that have nothing to do with impairments.
I mean earlier I said we're all walking around with this map, this
representation of the world around us so we can see edges, we can see
colors, except for folks that are color blind of course, and we also
have a map of emotional experience. We have a map of whether or not
certain people are trustworthy, certain people aren't trustworthy. A
few years ago I was at a course and a woman came up to me and she
said, you know, 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, okay, 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, perhaps some of you are having that
right now. 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.
And that's because our nervous system has two broad sets of functions.
Some of those functions are reflexive. Things like our breathing, our
heart rate, our obvious ones, but other aspects are reflexive like our
ability to walk. 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, it's 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 and you should
immediately say, well, kids don't go into school and say, oh, I want
to learn language or I want to learn social interactions, and that's
the beauty of childhood. The whole brain has this switch flipped that
is making change possible but after that we have to be deliberate. 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.
In this case, I believe that she came and told me that my voice was
really awful for her to listen to not to make me feel bad or for any
other reason except that she wanted it to not be the case. And she
knew I wasn't going to stop talking. So she decided to call it to her
consciousness and mine as well. So that's important. If you want to
learn something or you want to change your nervous system in any way,
whether or not it's because of some impairment or because of something
that you want to acquire, a cognitive skill, a motor skill, an
emotional skill, the first thing is recognizing what that thing is.
And that often can be the hardest thing to identify but the brain has
the self recognition mechanisms and those self recognition mechanisms
are not vague, spiritual or mystical or even psychological concepts.
They are neurochemicals.
We're going to talk next about the neurochemicals that stamp down
particular behaviors and thoughts and emotional patterns and tell the
rest of the nervous system, this is something to pay attention to
because this is in the direction of the change that I want to make. So
I'll repeat that, there are specific chemicals that when we are
consciously aware of a change we want to make or even just that we
want to make some change, chemicals are released in the brain that
allow us the opportunity to make those changes. Now, there are
specific protocols that science tells us We have to follow if we want
those changes to occur. But that self-recognition is not a kind of
murky concept. What it is is it's our fore brain, 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 that 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 experienced 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. Now, this is
best illustrated through a little bit of scientific history. The whole
basis of neuroplasticity is essentially ascribed to two individuals,
although there were a lot more people that were involved in this work.
Those two individuals go by the name David Hubel and Torsten Wiesel.
David Hubel and Torsten Wiesel started off at Johns Hopkins, moved to
Harvard medical school. And in the seventies and eighties, they did a
series of experiments, recording electrical activity in the brain.
They were in the visual cortex, meaning they put the electrodes in the
visual cortex, and they were exploring how vision works and how the
visual brain organizes all the features of the visual world to give us
these incredible things We call visual perceptions. But Hubel was a
physician. And he was very interested in what happens when for
instance, a child comes into the world and they have a cataract, the
lens of their eye, isn't clear but it's opaque. Or when a kid has a
lazy eye or the eyes have what's called strabismus, which is when the
eyes either deviate outward or inward. These are very common things of
childhood, especially in particular areas of the world. And what David
and Torsten did is they figured out that there was a critical period
in which if clear vision did not occur, the visual brain would
completely rewire itself, basically to represent whatever bit of
visual information was coming in. So they did these experiments to
kind of simulate a droopy eye or a deviating eye where they would
close one eyelid and then what they found is that the visual brain
would respond entirely to the open eye. There was sort of a takeover
of the visual brain representing the open eye. Many experiments in
many different sensory systems followed up on this. There are
beautiful experiments for instance, from Gregg Recanzone's lab up at
UC Davis and Mike Merzenich's lab at UCSF showing that for instance if
two fingers were taped together early in development, so they weren't
moving independently, the representation of those two fingers would
become fused in the brain so that the person couldn't actually
distinguish the movements and the sensations of the two fingers
separately, pretty remarkable. All of this is to say that David and
Torsten's work, for which they won a noble prize, they shared it with
Rogers Barry, their work showed that the brain is in fact a customized
map of the outside world, we said that already. But that what it's
doing is it's measuring the amount of activity for a given part of our
body, one eye or the other, or our fingers, this finger or that finger
and all of those inputs are competing for space in the brain.
Now this is fundamentally important because what it means is that if
we are to change our nervous system in adulthood, we need to think
about not just what we're trying to get, but what we're trying to give
up. We can't actually add new connections without removing something
else. And that might seem like kind of a stinger but it actually turns
out to be a great advantage. One of the key experiments that David and
Torsten did was an experiment where they closed both eyes, where they
essentially removed all visual input early in development. Now this is
slightly different than blindness because it was transient, it was
only for a short period of time. But what they found is when they did
that there was no change. However, if they would close just one eye
there was a huge change. So when people tell you, oh at the end of
today's lecture, or 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 the ways I talked
about before strengthening and weakening of particular connections,
they have names like long-term potentiation, long-term depression,
which has nothing to do with emotional depression by the way, spike-
timing-dependent plasticity. I threw out those names not to confuse
you, but for those of you that would like more in-depth exploration of
those, please you can go google those and look them up, there are
great Wikipedia pages for them and you can go down the paper trail. I
might even touch on them on some subsequent episodes. 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? Well, David and Torsten won their Nobel prize and
they certainly deserved it. They probably deserved two because they
also figured out how vision works. And I might be biased 'cause
they're my scientific great-grandparents but I think everybody in the
field of Neuroscience agrees that Hubel and Wiesel, as they're called
H&W for those in the game, absolutely deserved a Nobel prize for
their work because they really unveiled the mechanisms of brain change
of plasticity. David passed away a few years ago, Torsten is still
alive, he's in his late 90s, he's still at the Rockefeller university.
He's sharp as a tack. He still jogs several miles a day. He's really
into art and a number of other things. He's also a super nice guy.
Hubel was a really nice guy as well, also he was a great Frisbee
player I discovered 'cause he beat me in a game of ultimate when he
was like 80, which still, it has me a little bit irked. But anyway,
Hubel and Wiesel did an amazing thing for science that will forever
change the way that we think about the brain. However, they were quite
wrong about this critical period thing.
The critical period was this idea that if you were to deprive the
nervous system of an input, say closing one eye early in development
and the rest of the visual cortex is taken over by the representation
of the open eye, that you could never change that unless you
intervened early. And this actually formed the basis for why a kid
that has a lazy eye or a cataract why, even though there's some issues
with anesthesia in young children, why now we know that you want to
get in there early and fix the cataract or fix the strabismus it's
what ophthalmologists do. However, their idea that you had to do it
early or else there was no opportunity to rescue the nervous system
deficit later on turned out wasn't entirely true. 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 a like a stone drum in front
of your 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 that the distance was getting greater. So
people could get very good at these tasks that you're 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. They're
not taking any specific drugs. They don't have any impairments that
we're aware of. And what it showed, 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 inside
of that answer is the opportunity for any of us to change our brain at
any point throughout our lifespan, essentially for anything that we
want to learn, that could be subtracting an emotion from an experience
we've had, it could be building a greater range of emotion, it could
be learning new information like learning a new language. It could be
learning new motor skill, like dance or sport or it could be some
combination of cognitive motor. So for instance, an air traffic
controller has to do a lot with their mind in addition to a lot with
their hands. So it's not just cognitive, it's not just motor but
combined. So we're going to talk about what that chemical is but to
just give you an important hint, that chemical is the same chemical of
stress. This is not a discussion about stress per se. In a future
podcast episode, we'll talk all about stress and tools to deal with
stress, something my lab works on quite extensively. And it's a topic
that I enjoy discussing. But this is a topic about brain change. And
what I just told you is that in order to change the brain you have to
pay careful attention. And the immediate question should be well, why?
Well, the answer is that when we pay careful attention there are two
neurochemicals, neuromodulators as they're called, that are released
from multiple sites in our brain that highlight the neural circuits
that stand a chance of changing.
Now it's not necessarily the case that they're going to change, but
it's the first gate that has to open in order for change to occur. And
the first neurochemical is epinephrin, 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 epinephrin in the brain, but
they are chemically identical substances. Epinephrin is released from
a region in the brainstem called locus coeruleus. Fancy name, you
don't need to know it unless you want to. Locus coeruleus sends out
these little wires we call axons such that it hoses the entire brain
essentially in this neurochemical, epinephrin. Now it's not always
hosing the brain with epinephrin. It's only when we are in high states
of alertness that this epinephrin is released. But the way this
circuit is designed, it's very nonspecific. It's essentially waking up
the entire brain and that's because the way that epinephrin works by
binding particular receptors is to increase the likelihood that
neurons will be active. So no alertness, no neuroplasticity. However,
alertness alone is not sufficient. As we would say, it's necessary but
not sufficient for neuroplasticity. We know this is true also from the
work of Hubel and Wiesel where they looked at brain plasticity in
response to certain experiences in subjects that were either awake or
asleep. And I hate to break it to you but you cannot just simply
listen to things in your sleep and learn those materials. Later I'll
talk about how you can do certain things in your sleep that you're
unaware of that can enhance learning of things that you were aware of
while you were awake. But that is not the same as just listening to
some music or listening to a tape while you sleep and expecting it to
sink in, so to speak. Epinephrin is released when we pay attention and
when we are alert. But the most important thing for getting plasticity
is that there'll be epinephrin 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. There are a number of different names of these
aggregates of neurons. You don't need to know the names, 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.
Costello snoring off to my right, the lights that are in the room, the
presence of my computer to my left, all of that is coming in. But when
I pay attention to something like if I really hone in on Costello
snoring, I create a cone of attention and what that cone of attention
reflects is that acetylcholine is now amplifying the signal of sounds
that Costello is making with his snoring and essentially making that
signal greater than all the signal around it, 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, Costello's snoring
becomes more salient, more apparent relative to everything else going
on. Acetylcholine acts as a spotlight but epinephrin 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
buddying physicians or going to medical school, you should know that.
If you have acetylcholine released from the brainstem, acetylcholine
released from nucleus basalis and epinephrin, you can change your
brain.
And I can say that with confidence because Merzenich and Recanzone as
well as other members of the Merzenich lab, Michael Kilgard and others
did these incredible experiments where they stimulated the release of
acetylcholine from nucleus basalis either with an electrode or with
some other methods that we'll talk about. And what they found was when
you stimulate these three brain regions, locus coeruleus, the
brainstem source of acetylcholine and then the basal forebrain source
of acetylcholine. When you have those three things whatever you happen
to be listening to, doing or paying attention to immediately in one
trial takes over the representation of a particular area of the brain.
You essentially get rapid massive learning in one shop. And this has
been shown again and again and again in a variety of papers also by a
guy named Norman Weinberger from UC Irvine. And it is now considered a
fundamental principle of how the nervous system works. So while Hubel
and Wiesel talked about critical periods in developmental plasticity,
it's very clear from the work of Merzenich and Weinberg and others,
that if you get these three things, if you can access these three
things of epinephrin, 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. You cannot just passively
experience things and repetition can be important, but the way to use
repetition to change your brain is fundamentally different. So now
let's talk about how we would translate all the scientific information
and history into some protocols that you can actually apply, because I
think that's what many of you're interested in.
And I'm willing to bet that most of you are not interested in lowering
electrodes into your nucleus basalis and frankly, neither am I. In
episode one of the Huberman Lab Podcast, I described the various ways
that people can monitor and change their nervous system. Those ways
include brain machine interface, pharmacology, behavioral practices,
and those behavioral practices of course can include some dos, do this
and some don'ts, don't do that, et cetera In thinking about
neuroplasticity, I want to have a very frank conversation about what
one can do but also acknowledge this untapped capacity that I'm just
not hearing about out there, which is one can also combine behavioral
practices with pharmacology. One can combine behavioral practices with
brain machine interface, and you don't have to do that. In fact, I'm
not recommending you do anything in particular. As always, I'll say it
again, I'm not a physician, so I don't prescribe anything. I'm a
professor, so I profess a lot of things. What you do with your health
and your medical care is up to you. You're responsible for your health
and wellbeing. 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 epinephrin, 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. All the tools and more
science than probably you ever wanted to hear about sleep and how to
get better at sleeping and timing your sleep et cetera and naps and
all of that is in episodes two, three, four, and five of the Huberman
Lab Podcast. So I encourage you to refer to those if your sleep is not
where you would like it to be. Your ability to engage in deliberate
focused alertness is in direct proportion to how well you are sleeping
on a regular basis. I think that's kind of an obvious one. So get your
sleep handled. 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 cheques 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, you know,
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
epinephrin and getting alert and activated, it doesn't really matter.
Epinephrin 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 epinephrin.
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
at 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.
I just want to briefly mention one little aside there because I've got
a friend who's a physician, he's a cardiologist who has a really
interesting theory. This is just theory, but I think it will resonate
with a lot of people, which is that, you've all heard of this molecule
dopamine that gives us the sense of reward when we accomplish
something. Well, we also want to be able to access dopamine while
we're working towards things, enjoy the process as they say, 'cause it
has all sorts of positive effects gives us energy, et cetera. With my
friend, what he says is, you know, there's many many instances where
someone will come to him and say, "You know what, I'm going to write a
book." And he says, "Oh, that's great. I'm sure the book's going to be
terrific and you really should write a book." And then they never go
do it. And his theory is, if you get so much dopamine from the reward
of people saying, Oh yeah, you're absolutely going to be able to do
that, you might not actually go after the reward of the accomplishment
itself. So be aware these positive reinforcements also. I'm not saying
people should flagellate themselves to the point of victory in
whatever they're pursuing, but motivation is a tricky one. So I
suggest that everyone asks themselves what is it that I want to
accomplish? And what is it that's driving me to accomplish this and
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, you know
kind of like bro, science buddies, I have those friends too, this is a
Nobel prize winning colleague who chews Nicorette while he works. He
used to be a smoker. He quit smoking because of fear of lung cancer,
seemed like a smart choice, but he missed the level of focus that he
could bring to his work. This is somebody who has had very long
career. And if you ever meet with him, unfortunately I can't name him.
If you ever meet with him what you realize is he chews about five
pieces of Nicorette an hour, which I am not suggesting people do. But
when I asked him, "Why are you doing this?" He said, "Well, increases
my alertness and focus." And also his theory and I want to really
underscore that it's theory not scientifically supported yet, is that
it offsets Parkinson's and Alzheimer's. It is true that nucleus
basalis is the primary site of degeneration in the brain, in people
that have dementia and Parkinson's and it's what leads to a lot of
their inability to focus their attention, not just deficits and
plasticity. So he might be onto something. 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, some of whom are
scientists, writers and artists and musicians are familiar with the
effects of nicotine from the era where a lot of people smoked and
fortunately fewer people smoke now. So if you're interested in the
pharmacology, there are supplements and things that can increase
cholinergic transmission in the brain. I'm not suggesting you do this
but 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. That's what's going to create a
mark in your brain and the potential for plasticity. Things that
increase acetylcholine, besides nicotine or Nicorette, the nicotine
could come from a variety of sources or things like alpha-GPC or
choline. There are a number of these things. I would encourage you to
go to examine.com, the website and just put in acetylcholine and it
will give you a list of supplements as well as some of the dangers of
these supplements that are associated with cholinergic transmission.
But I would be remiss and I would be lying if I didn't say that there
are a lot of people out there who are using cholinergic drugs in order
to increase their level of focus.
And since we're coming up on the Olympics, I don't want to get anyone
in trouble but I'm well aware that the fact that the sprinters are
really into cholinergic drugs because not only is acetylcholine
important for the focus that allows them to hear the gun and be first
out the blocks on the sprints. That's a lot of where the race is won,
hearing that gun and being the quickest on reaction time. So they take
cholinergic agents for that as well as acetylcholine is the molecule
that controls nerve to muscle contraction. So your speed of reflexes
is actually controlled by this nicotinic transmission as well. So lots
to think about in terms of acetylcholine in sport and mental acuity,
not just plasticity. Now for most of you, you probably don't want to
chew Nicorette, definitely don't want to smoke cigarettes or take
supplements for increasing acetylcholine. So what are some ways that
you can increase acetylcholine? And there, it's going to sound like a
bit of a circular argument but you to increase focus. How do you
increase focus? You know, people are so familiar with sitting down,
reading a couple pages of a book and realizing that none of it sunk in
or talking to someone and seeing their mouth move, maybe even nodding
your head subconsciously and none of it sinks in.
This can be very damaging for school, work performance and
relationships as many of you know. Costello incidentally never seems
to pay attention to anything I say while looking directly at me, which
contradicts what I'm about to say, which is that 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. And
as I mentioned before, 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 which if you watch the sleep episodes, you know reduces this
molecule that makes us sleepy called adenosine. I drink plenty of
caffeine. I'm a heavy user of caffeine. I don't think abuser of
caffeine. I think in reasonable amounts provided we can still fall
asleep at night, caffeine can be a relatively safe way to increase
epinephrin. Now, many people are now also using Adderall. Adderall
chemically looks a lot like amphetamine and basically it is
amphetamine.
It will increase epinephrin release from locus coeruleus, it will wake
up the brain and that's why a lot of people rely on it. It does have a
heavy basis for use in certain clinical syndromes prescribed such as
attention deficit. However, it also has a high probability of abuse
especially in those who are not prescribed it. Adderall will not
increase focus, it increases alertness. It does not touch the
acetylcholine system. And if those of you that are taking Adderall
say, "Well, it really increases my focus overall", that's probably
because your autonomic nervous system is just veering towards what we
call parasympathetic. You're really just very sleepy and so it's
bringing your levels of alertness up. As I mentioned, Adderall is very
problematic for a number of people as it can be habit forming.
Learning on Adderall does not always translate to high-performance off
or on Adderall at later times. And the Adderall discussion is a
broader one that perhaps we should have with a psychiatrist in the
room at some point because it is a very widely abused drug at this
point in time. 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 our periphery. It's a simple
experiment you can do right now. If you're listening to this, you can
still do it. You can hold your feet or your hands out in front of you.
Provided that you're sighted you should be able to see how many
fingers you have in front of you. For me, it's five. I still got all
five fingers, amazingly enough. If I move my hand off to the side, I
can't see them with precision, but as I moved them back into the
center of my visual field I can see them with precision. And that's
because the density, the number of pixels in the center of my visual
field is much higher than it is in the 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. [door banging] If it... That was the dog
bumping into the wall, forgive me. 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 see, 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, even if you're engaged in a physical task.
Now there's a remarkable phenomenon in animals where animals that have
their eyes on the side of their head are scanning the entire visual
environment all the time. They're not focused on anything. Think
you're grazing animals, your cows, your sheep your birds, et cetera.
But think about a bird picking up seeds on the beach or on concrete.
That bird's head is up here. It's up about a foot off the ground, or
if it's a small bird about six inches off the ground and its eyes are
on the side of its head and yet it has this tiny beak that can quickly
pick up these little seeds off the ground with immense precision. Now,
if you try to do that by staring off to the sides of the room and
picking up items in front of you with high precision at that tiny
scale, little tiny objects, you will miss almost every time. They do
it perfectly and they don't smash their beak into the ground and
damage it, they do it with beautiful movement acuity also. So how do
they do it? How do they create this focus or this awareness of what's
in front of them? It turns out as they lower their head, their eyes,
very briefly move inward, in what's called a vergence eye movement.
Now their eyes can't actually translocate in their head, they're fixed
in the skull, just like yours and mine are. But when we move our eyes
slightly inward, maybe you can tell and do it's like so basically
shortening or making the inter pupillary 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
brainstem that trigger the release of both norepinephrine, epinephrin
and acetylcholine. Norepinephrine is kind of similar to epinephrin. 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 or 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
epinephrin 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. I might think
that I'm only looking at the paper that I'm reading. I'm only looking
at my screen, but actually my eyes are probably darting around a bit.
Experiments have been done on this. Or I'm gathering information from
too many sources in the visual environment. Now, presumably because
it's me, I've already had my coffee, I'm hydrated. I'm well rested, I
slept well. And I still experienced these challenges in focusing
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, if you wear contacts or you wear corrective lenses, that's
fine. You of course would want to use those. You don't want to take
those off and use a blurry image. The finer the visual image and the
more that you can hold your gaze to the visual image, the higher your
levels of attention will be. Many times on Instagram and here I've
been teased for not blinking very often.
That's actually a practiced thing. We blink more as we get tired,
which as you hear it you'll probably just say, duh. As we get tired,
the neurons in the brainstem that are responsible for alertness and
that hold the eyelids open start to falter and our eyelids start to
close. This is why it's hard, the words, "I could barely keep my eyes
open" which may be how you feel right now. But assuming that you're
paying attention and you're alert, when you're very alert, your eyes
are wide, your eyes are open. And as you get tired, your eyelids start
to close. Blinks, actually reset our perception of time and space.
This was shown in a beautiful paper in Current Biology. I'll be sure
to post the reference in the notes. And blinking of course is
necessary to lubricate the eyes. People blink because their eyes might
get dry. But if you can keep focused by blinking less and by focusing
your eyes to a particular location that's probably pretty creepy for
you to experience as I'm doing this. But the more that you can do this
the more that you can maintain a kind of a cone or a tunnel of mental
focus. And so I'm sort of revealing my practice which is that I've
worked very hard through blinking contest with my 14-year-old niece
who still beats me every time and it really bothers me, but also just
through my own self practice of learning to blink less and focus my
visual attention on a smaller region of space. Now for me, that's
important because I'm mainly learning things on a computer screen. If
you're going to be doing sport, it's quite a bit different and we can
discuss how you might translate to that to sport. In fact, in the next
episode, I'm going to talk all about how plasticity and the focus
mechanisms relate to learning of movement practices and coordinated
movements. It's an entire discussion unto itself but the same
principle holds. So we need alertness. You can get that through mental
tricks of motivation, fear or love, whatever it is, pharmacology,
please do it healthfully. You know, caffeine if that's in your
practice, certainly want to be well hydrated that increases actually
will increase alertness. Well, having a very full bladder will
increase alertness although you don't want your alertness to be so
high that all you can think about is the fact that you have to go
urinate 'cause that's very distracting. You don't want your alertness
to go through the roof. You need focus and visual focus is the primary
way in which we start to deploy these neurochemicals. Now you may ask,
well, what about the experiment where people were feeling this
rotating drum or listening to the auditory cue that doesn't involve
vision at all?
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. Incidentally does anyone know the two animals
that have the best hearing in the world? The absolute best hearing is
many orders of magnitude better than humans.
It turns out it's the elephant. That might not surprise you, they have
huge ears and the moth which probably will surprise you. I didn't even
know that moths could hear. but now it explains why they're so hard to
catch. If you are not sighted, you learn how to do this with your
hearing. If you're somebody who braille reads, you learn how to do
this with your fingers. If you look at great piano players like Glenn
Gould, they often times will turn their head to the side. You think
about some of the great musicians like Stevie Wonder that were blind,
right? He would look away because he had no reason to look at the
keys, but oftentimes they'll orient an ear or one side of their head
to the keys on the piano. As I mentioned before, people who are non-
sighted have better pitch. So we have these cones of attention that we
can devote. And for most people, vision is the primary way to train up
this focus of building 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 epinephrin 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.
And you can practice this ability to stare for long periods of time
without blinking. I know it's a little eerie for people to watch, but
if your goal is to learn how to control that visual window for sake of
controlling your focus, it can be an immensely powerful portal into
these mechanisms of plasticity, because we know it engages things like
nucleus basalis and these other brainstem mechanisms.
I get a lot of questions about attention deficit hyperactivity
disorder, ADHD, and attention deficit disorder. Some people actually
have clinically diagnosed ADD and ADHD. And if you do, you should
certainly work with a good psychiatrist to try and figure out the
right pharmacology and/or behavioral practices for you. Many people,
however, have given themselves a low grade ADHD or ADD because of the
way that they move through their world. They are looking at their
phone a lot of the time. It's actually very easy to anchor your
attention to your phone for the following reason. First of all, it's
very restricted in size. So it's very easy to limit your visual
attention to something about this big. It's one of the design features
of the phone. The other, is that just as you've probably heard a
picture is worth a thousand words, well, a movie is worth 10,000
pictures. Anytime we're looking at things that have motion, visual
motion, our attentional system will naturally gravitate towards them,
towards those movies. It's actually much harder to read words on a
page than it used to be for many people, because we're used to seeing
things spelled out for us in YouTube videos or videos where things
move in a very dramatic. It is true that the more that we look at
those motion stimulate, the more that we're seeing movies of things
and things that are very dramatic and very intense, the worst we're
getting at attending to things like text on a page or to listening to
something like a podcast and extracting the information so much so
that I think many people have asked me, "Hey you know what, why aren't
you providing intense visuals for us to look at?" Well, frankly, it's
because a lot of people are consuming this content through pure
auditory, through, it's by listening. And I want them to be able to
digest all the material. But in addition to that, if you think about
the areas of life that dictate whether or not we become successful,
independent, healthy individuals, most of those involve the kind of
boring practices of digesting information on a page. Boring because
it's not as exciting in the moment perhaps as watching a movie or
something being spoonfed to us. But the more attention that we can put
to something, even if it's fleeting and we feel like we're only
getting little bits and pieces, shards of the information as opposed
to the entire thing, that has a much more powerful effect in engaging
this cholinergic system for plasticity than does, for instance,
watching a movie. And that's because when we watch a movie, the entire
thing can be great, it can be awesome. It can be this overriding
experience but I think for all those experiences, if you're somebody
who's interested in building your brain and expanding your brain and
getting better at various things, in feeling better, doing better, et
cetera, one has to ask how much of my neurochemical resources am I
devoting to the passive experience of letting something, just kind of
overwhelm me and excite me, versus something that I'm really trying to
learn and take away. And now there's another I enjoy movie content and
TV content all the time. I scroll Instagram often. But we are limited
in the extent to which we can grab a hold of these acetylcholine
release mechanisms or epinephrin. And I think that we need to be
careful that we don't devote all our acetylcholine and epinephrin, all
our dopamine for that matter to these passive experiences of things
that are not going to enrich us and better us. So that's a little bit
of an editorial on my part but the phone is rich with movies, it's
rich with information. The real question is is the information rich
for us in ways that grow us and cultivate smarter, more emotionally,
you know emotionally evolved people, or is it creating what's it doing
for our physical wellbeing for that matter? So I don't want to tell
people what to do or not to do but think carefully about how often
you're focusing on something and how good you are or poor you are at
focusing on something that's challenging. So once you get this
epinephrin, 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 lasts about 90 minutes. The typical
learning about should be about 90 minutes. I think that learning about
will no doubt include five to 10 minutes of warmup period. I think
everyone should give themselves permission to not be fully focused in
the early part of that about. But that in the middle of that about 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 wifi. I put my phone in the other room. If I
find myself reflexively getting up to get the phone I will take the
phone and lock it in the car outside. If I find myself going to get it
anyway, I am guilty of giving away the phone for a period of time or
even things more dramatic, I've thrown it up on my roof before so I
can't get to it till the end of the day. That thing is pretty
compelling and we come up with all sorts of reasons why we need it, to
be in contact with it but 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. Feel
free to blink, of course, but you can greatly increase your powers of
focus and the rates of learning which is anchored in all the work of
Merzenich, Hubel and Wiesel and others.
Now 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
about of learning, that night and the following nights, while you're
asleep the neural circuits that were highlighted if you will with
acetylcholine transmission will strengthen and other 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 will have acquired the knowledge forever unless
you go through some process to actively unlearn it. And we will talk
about unlearning in a later episode. 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 about 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 are synopses are more biased to change.
Now, if you don't ever get that deep sleep then you probably won't get
those changes. There's 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 signs
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 they're 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 where
the two 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. So the key to plasticity in childhood is to
be a child. The key to plasticity in adulthood is to engage alertness,
engage focus and then to engage Non Sleep Deep Rest and deep sleep
while you're in your typical about of sleep.
I always get asked, "How many bouts of learning can I perform?" Well,
I know people that train up these visual focus mechanisms to the point
where they can do several 90 minute bouts throughout the day, as many
as three or four. And some of them are also inserting Non Sleep Deep
Rest as well. Now that can get pretty tricky. A lot of people find
that they can recover best from these intense bouts of focused
learning by doing some motor activity where you get into self-
generated optic flow.
And that should make sense if you've ever heard me lecture about
stress which I've done a little bit in various podcasts. When we are
in a mode of self-generated optic flow like walking or running or
cycling and things are just floating past us on our retina, we're not
really looking anywhere in particular, so this is the opposite of a
tight window of focus. When we do that, there are areas of the brain
like the amygdala which are involved in releasing epinephrin and
create alertness. At the extremes, it creates fear but certainly
alertness, those are all shut down. So it's its own form of non sleep
deep rest. So some people find it much more pleasurable and practical
to engage in a focused about of learning and then go do some activity
that involves what we would essentially call worldlessness where
you're not really thinking about much of anything. And so for those of
you that listen to audio books or podcasts while you run you may want
to consider whether or not that's how you want to spend your time
right now. I'd love it if you were listening to this podcast while you
run or cycle, but I'm much more interested in you actually getting the
benefits of neuroplasticity than just listening to me for the sake of
listening to me. So 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.
And there are good scientific data to support these sorts of things,
including the Cell Reports paper that I mentioned a few moments ago.
I want to synthesize some of the information that we've covered up
until now. This entire month is about neuroplasticity. Today's episode
has covered a lot, but by no means has it covered all of the potential
for neuroplasticity and protocols for plasticity. We will get into all
of it. But 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. Early, from
birth until 25, mere exposure to a sensory event can create
plasticity. That could be a good thing or a bad thing. We're going to
talk about unlearning the bad stuff, traumas, et cetera in a
subsequent episode this month. 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.
There are four episodes devoted to that 24-hour cycle and the cycles
of alertness and sleep. I encourage you to listen to those if you
haven't had the opportunity to yet or 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'd be a terrible time to
get into passive observance or just letting your time get soaked away
by something. That is a valuable asset, that epinephrin, released from
your brainstem 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. And then you could start to think about
the behavioral practices, maybe the pharmacologic practices like
caffeine, hydration, et cetera that will support heightened levels of
alertness. Attention is something that can be learned and attention is
critical for creating that condition where whatever it is that you are
engaging in will modify your brain in a way that you won't have to
spend so much attention on it going forward. That's the essence of
plasticity, that things will eventually become reflexive. The language
that you're learning, the motor movement, the cognitive skill, the
ability to suppress an emotional response or to engage in emotional
response depending on what your goals are and what's appropriate for
you. Increasing acetylcholine can be accomplished pharmacologically
through nicotine. However, there are certain dangers for many people
to do that as well as the 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. Now, the
other way to get high levels of visual focus and alertness is to have
a panic or to have a situation that's very, very bad. You will be
immediately focused on everything related to that situation, but
that's unfortunate. 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
than to what you see. But for most people they're trying to learn
information, cognitive information, or they're trying to learn how to
hear the nuance in their partner's explanations of their emotionally
challenging events, et cetera. And just remember, by the way, what I
said earlier, which is that if you really want somebody to listen to
you and really hear what you're saying and what's underlying it, you
should not, and cannot expect them to look directly at you while you
do that. That's actually going to limit their ability to focus. I'm
trying to rescue a few folks out there who might be in this struggle.
I of course have never been in this struggle. And that was supposed to
be a joke. I'm very familiar with that struggle but I know that one
can get better at listening, one can get better at learning, one can
get better at all sorts of things by anchoring in these mechanisms.
Now, of course you can also combine protocols. You can decide to
combine pharmacology with these learning practices. Many people in
communities do that. Many people are doing that naturally by drinking
their coffee right before they do their learning. But I would also
encourage you to think about how long those learning bouts are. If you
think you have ADD or ADHD, see a clinician but you should also ask
yourself are you giving up the best period of focus that you have each
day naturally to some other thing like social media or some other
activity that doesn't serve you well or are you devoting that period
to the opportunity to learn? 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,
they're 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, or typically when you wake up os 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
you kind of mindlessly it might seem in a chair, just letting your
thoughts move around after a learning about will accelerate the rate
of plasticity that's been shown in quality peer reviewed studies. And
then of course, deep sleep. And so what we can start to see is that
plasticity is your natural right early in life. But after about age 25
you have to do some work in order to access it. But fortunately, these
beautiful experiments of Hubel and Wiesel and Merzenich and Weinberger
and others point in the direction of what allows us to achieve
plasticity, it points to the neurochemicals and the circuits. And we
now have behavioral protocols that allow us to do that.
I also really want to emphasize that there's an entire other aspect of
behavioral practices that will allow us to engage in plasticity that
don't involve intense focus on emotionality but involve a lot of
repetition. So there's another entire category of plasticity that
involves doing what seemed like almost mundane things but doing them
over and over again repeatedly and incorporating the reward system
that involves dopamine. So today I talked about the kind of plasticity
that comes from extreme focus. You would get that extreme focus and
alertness naturally through a harder, difficult event that you didn't
want. That's the kind of stinger but your brain is designed to keep
you safe so it wants to get one trial learning from things like
touching a hot stove or engaging with a really horrible person. You
can get incredible plasticity of positive experiences of things that
you want by engaging this high focus regime and then rest, non sleep
deep rest, and sleep. And there's another aspect of plasticity which
we will explore next episode as well as when we explore movement-based
practices for enhancing plasticity and plasticity of movement itself.
And those are not of the high attention kind of high emotionality or
in the intensity of the experiences that I described today. Those are
more about repetition and reward and repeat, repetition, reward,
repeat, and they are used for a distinctly different category of
behavioral change more of which relate to habits as opposed to
learning of particular types of information that allow us to perform
physically, cognitively or adjust our emotional system. So I'm going
to stop there. I'm sure there are a lot of questions. Please put your
questions in the comment section below and please remember that this
entire month we're going to be exploring neuroplasticity. So this
discussion/lecture, I wish it was more of a back and forth, but this
is what the format offers us. So please do put your questions in the
comment section and I will address them in the other episodes coming
soon on neuroplasticity. As I say that I'm reminded that many of you
are listening to this on Apple or Spotify and therefore there isn't an
opportunity to leave comments aside from the rating section on Apple.
So if you have specific topics related to neuroplasticity that you
would like me to cover in the subsequent episodes this month please go
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Timestamps below.
00:00 Introduction
03:50 Plasticity: What Is it, & What Is It For?
06:30 Babies and Potato Bugs
08:00 Customizing Your Brain
08:50 Hard-Wired Versus Plastic Brains
10:25 Everything Changes At 25
12:29 Costello and Your Hearing
13:10 The New Neuron Myth
14:10 Anosmia: Losing Smell
15:13 Neuronal Birthdays Near Our Death Day
16:45 Circumstances for Brain Change
17:21 Brain Space
18:30 No Nose, Eyes, Or Ears
19:30 Enhanced Hearing and Touch In The Blind
20:20 Brain Maps of The Body Plan
21:00 The Kennard Principle (Margaret Kennard)
21:36 Maps of Meaning
23:00 Awareness Cues Brain Change
25:20 The Chemistry of Change
26:15 A Giant Lie In The Universe
27:10 Fathers of Neuroplasticity/Critical Periods
29:30 Competition Is The Route to Plasticity
32:30 Correcting The Errors of History
33:29 Adult Brain Change: Bumps and Beeps
36:25 What It Takes to Learn
38:15 Adrenalin and Alertness
40:18 The Acetylcholine Spotlight
42:26 The Chemical Trio For Massive Brain Change
44:10 Ways To Change Your Brain
46:16 Love, Hate, & Shame: all the same chemical
47:30 The Dopamine Trap
49:40 Nicotine for Focus
52:30 Sprinting
53:30 How to Focus
55:22 Adderall: Use & Abuse
56:40 Seeing Your Way To Mental Focus
1:02:59 Blinking
1:05:30 An Ear Toward Learning
1:06:14 The Best Listeners In The World
1:07:20 Agitation is Key
1:07:40 ADHD & ADD: Attention Deficit (Hyperactivity) Disorder
1:12:00 Ultra(dian) Focus
1:13:30 When Real Change Occurs
1:16:20 How Much Learning Is Enough?
1:16:50 Learning In (Optic) Flow/Mind Drift
1:18:16 Synthesis/Summary
1:25:15 Learning With Repetition, Forming Habits
As always, thank you for your interest in science!
Please note that The Huberman Lab Podcast is distinct from Dr.
Huberman's teaching and research roles at Stanford University School
of Medicine. The information provided in this show is not medical
advice, nor should it be taken or applied as a replacement for medical
advice. The Huberman Lab Podcast, its employees, guests and affiliates
assume no liability for the application of the information discussed.
[Title Card Photo Credit: Mike Blabac https://www.blabacphoto.com/]