Welcome to the huberman Lab podcast where we discuss science and science based tools for everyday life. I'm Andrew huberman, and I'm a professor of neurobiology and Ophthalmology at Stanford school of medicine.
Today. We are discussing
working memory
working memory as a special category of memory in which we are able to hold small amounts of information in our mind for short periods of time working memory is also very closely related to attention. So for any of you
That are interested in how to develop better focus and attention understanding what working memory is and some of the things that you can do to
improve your working memory can be very beneficial
today. I'm going to talk about what working memory is including some of the
underlying biology although I
promise irrespective of whether or not you know, any biology or you are an expert in biology. I'll make the conversation accessible to you. In addition. I will talk about tools to improve working memory and I'll also compare working memory to other
forms of memory.
Marie like long term memory and short-term
memory and through that understanding I'm confident that you'll be able to develop better focus as well as be able to commit certain forms of
information to your short and long-term memory stores before we
begin. I'd like to emphasize that this podcast
is separate from my teaching and research roles at Stanford
it is however a part of my desire and effort to bring zero cost to Consumer information about science and science related tools to the general public in keeping with that theme. I'd like to thank the sponsors of today's podcast our
Sponsor is Martina. Martina makes loose leaf and ready to drink yerba mate. I often discuss yerba mate is benefits such as regulating blood sugar. Its high antioxidant content the ways that it can improve digestion and possible neuroprotective effects. I also drink yerba mate because I love the taste while there are a lot of different choices of yerba mate drinks out there. I love matina because again, they have the no sugar variety as well as the fact that both their loose leaf and their kin varieties are of the
the absolute best quality so much so that I decided to become a partial owner in the company. Although I must say even if they hadn't allowed me to do that. I would be drinking montina is the cleanest tasting and best yerba mate. You can find I love the taste of brood loose-leaf Martina yerba mate and I particularly love the taste of Martinez new canned cold brew zero sugar yerba mate, which I personally help them
develop if you'd like to try matina go to drink
mattina.com hubermann.
Right Now matina is offering a free one pound bag of loose leaf tea yerba mate tea and free shipping with the purchase of two cases of their cold brew yerba.
Mate. Again, that's drink Martina.com huberman to get the
free bag of yerba mate loose leaf tea and free shipping. Today's episode is also brought To Us by better
help better help offers Professional Therapy with a licensed therapist carried out online.
I've been going to therapy for well over 30 years
initially. I didn't have a choice. It was a condition of being allowed.
To stay in school,
but pretty soon. I realized that therapy is extremely valuable. In fact, I consider doing regular therapy just as important as getting regular
exercise including cardiovascular exercise and resistance training, which of course I also do every week. The reason I know therapy
is so valuable is that if you can find a therapist with whom you can develop a really good rapport, you not only get terrific support for some of the challenges in your life. But you also can derive tremendous insights from that therapy insights that can allow you.
That are not just your emotional life and your relationship life. But of course also the relationship to yourself and to your professional life to all sorts of career goals. In fact, I see therapy is one of the key components for meshing together all aspects of one's life and being able to really direct ones focus and attention
toward what really matters if you'd like to try better help go to better help.com huberman to get 10% off your first month again. That's better help.com hubermann.
Today's episode is also brought To Us by Helix sleep helix.
Sleep makes mattresses and pillows that are of the absolute highest quality. I've spoken many times before on this and other podcasts about the fact that sleep is the foundation of mental health physical health and performance. One of the key things to getting a great night's sleep is to make sure that your mattress matches your sleep requirements. The Helix website has a brief 2-minute quiz that if you go to it will ask you questions such as do you
sleep on your back your side of your stomach. Do you tend to run hot or cold during
the middle of the night as well as some other questions that allow you to determine the optimal mattress for you?
When I took the quiz, I personally matched to their
dusk mattress. Do you SK which
has allowed me to significantly improve my sleep. So if you're interested in significantly improving your sleep go to Helix sleep.com huberman take their brief to minute quiz and they'll match you to a customized mattress and you'll get up to 350 dollars off any mattress order and to free pillows. So again, if you're interested in trying Helix, go to Helix sleep.com
huberman for up to three hundred fifty dollars off and to free.
Close. Okay. Let's talk about working memory and let's start off this discussion by comparing working memory to other forms of memory that most people are more familiar with or at least when most people hear the word memory. The typically are thinking about
long-term memory, like one's ability to remember the capitals of states or countries the different continents
directions from one location to another even ones named all of those things are examples of
long-term memory. Now,
I want to emphasize that long-term memory really has two
It's there are what we call declarative long-term memories. So these are the things that we can
declare things like facts about ourselves or the world or others. And then there are procedural long-term memories procedural long-term memories as the name suggests
are aspects of our memory that allow us to perform certain procedures. They are literally action steps that we take to for instance ride a bicycle or drive a car which by the way we might not be conscious of ourselves doing
after we learn that is after
After we pass information into our procedural long-term memory,
but even once those things become reflexive they are stored in our long-term memory. Now a discussion of long-term memory is not the focus today, but me being a neuroscientist and I like to thank you all generally being interested in the underlying biology. I'll just mention that there is a key structure within the brain that is part of a larger neural
network that is a collection of structures,
which is absolutely essential for the formation and
storage of long-term memories, and that's the
Hippocampus which in Latin means seahorse and it does look a little bit like a seahorse, but
we actually have one on each side of your brain. So we say hippocampi plural and so what we know is that if people have damage to their hippocampus of any kind that people have trouble accessing or forming
long-term memory sometimes
both and there's a lot more that we could say about long-term memory indeed. I did an entire episode of The huberman Lab podcast about the formation and storage of long-term memories, including some tools to improve long-term memory.
Touch on a few of those tools later today, but you can access that episode. If you go to
huberman lab.com and just put memory into the search function and you'll find it there in the meantime if we want to understand working memory. We not only have to understand how it's different from long term memory. But also how it's different from short-term memories short-term memory
is a capacity that we all have that as the name suggests represents a short-term
memory bank for information that may or may not get passed into long-term memory.
So for instance if you
And anything and of course you have if you can understand what I'm saying, you've learned English language, if you can write you've learned how to write it Etc.
Well in order to learn those things and to commit them
to long-term memory the information required to do those
things and to have that knowledge
needed to be held in short-term memory and
short-term memories are the sorts of memories that we maintain for somewhere between a few minutes and potentially a few hours maybe a little bit longer but only a certain percentage
of that is passed in
to our long-term memory. So for instance, if you listen to this podcast or you go to a course lecture whether or not that lecture is about cognitive material or whether or not it's about learning a new physical skill
regardless of what you learn. You're only going to learn a
certain amount of that information,
but we're we to examine how much of the
information you just heard or that you're hearing. Now you remember immediately after
this podcast episode as compared to say a week
later. We know based on gosh probably.
Scientific papers and studies that you are going to have more information in your short-term memory stores shortly after being exposed to new information. Then you will later in other words only a small percentage of what we perceive what we see what we hear etcetera gets passed into short-term memory and then only a fraction of that gets passed into long-term memory now the neural circuits for short-term memory and the passage of short-term memories into long-term memory involve a lot of
different brain structures, but here again, we can
implicate the hippocampus.
Because
the actual passage of short-term memories into long-term
memories occurs in part within the hippocampus and
then a lot of people don't know this some of the memories that we think of as
long-term memories are actually distributed into the neocortex, which is the outer portion of the brain.
Now the point here is less to fill your mind with
different names of things and nomenclature, but rather
to get you thinking about what's involved
in creating short and long-term memories and equally
important that even though the hippocampus is critically involved.
Often the formation of short and long-term memories that the
formation of short and long-term memories is really a network phenomenon. In fact
among the more important themes that comes up again and again on this podcast any time that we're talking
about Neuroscience or actually biology in any case
is that rarely if ever is there one location
in the brain where something happens typically it's a network phenomenon meaning it's the collaboration of a bunch of different brain areas passing information from one location to the next and storing it in a kind of distributed way
now.
Another key thing to understand about working memory and how it is
different from short and long-term memory. Is that the
formation of short and long-term memories almost always involves neuroplasticity neuroplasticity is the nervous systems ability
to change in response to experience. Now, there are different types of neuroplasticity. So
often when we hear about neuroplasticity in the
popular sphere people
don't emphasize that there are different types of
neural plasticity and it's worth paying a little bit of attention to what those different types are.
There is for instance what we call
long-term potentiation long-term potentiation or ltp. As the
acronym goes is the strengthening of connections between
neurons as a consequence
of their repeated firing very
closely together in time.
Okay, there's a lot more to it. But if you've ever heard the phrase fire together wire together, sometimes that is
misattributed to Donald Hebb who did talk about neuroplasticity. By the way. Donald have was a psychologist up in Canada who talked about
ecstasy in the context of lots of different
forms of learning but that fire together wire together phrase was not
actually stated by Donald Hebb it was stated by Carla shots my colleague
at Stanford and she was referring to ltp, but other forms of neuroplasticity that occur mainly in development when neurons fire very
closely in time and thereby strengthen those connections, which can
include ltp. Okay. So for now think of ltp as anytime that some small group of neurons could be
two neurons could be
Two thousand neurons are very active closely together in time and they have access to one another physically and the consequence is often not always but is often ltp. That is the strengthening of those connections such
that after that barrage of activity
subsides. Those neurons can speak to
each other they can
communicate through electrical activity and chemical activity much more easily. Their communication is
more robust. It's like
removing a wall between a
conversation.
Such that the conversation can take place more fluidly.
Now, there are other forms of neuroplasticity including LTD
long-term depression, which
unfortunately the name often calls to mind ideas about depression as a psychiatric or psychological symptom but has nothing to do with that long-term depression is simply the inverse of ltp. It's actually the weakening or the removal
of connections that we call synapses between neurons.
I want to emphasize that both ltp and LTD are both critically involved in.
Lots of different kinds of learning and both of them tend to be involved in the
formation of both short-term memories and
long-term memories. And this is very important in the removal
of short-term memories and long-term memories literally forgetting of certain things because as we all
know there are many things that we will never forget and there are also things that we almost always forget
now there's a third form of neuroplasticity that's involved in the formation of short and long-term memories that's important for us to discuss just
briefly, but I do want to emphasize that
That there are
not just three forms of neuroplasticity. There are
many other forms dozens. If not more things like Spike timing-dependent plasticity pillar paired pulse
facilitation and on and on but the
third type of neuroplasticity that I'd like to mention now is neurogenesis. Neurogenesis is the formation of new neurons. Now neurogenesis is robust in the developing nervous system. We know this its robust in the developing nervous system of animals and humans, however, neurogenesis the literal formation.
New
neurons in the brain is a very exciting idea and it does occur and it's very exciting in a way that has motivated lots of popular press Outlets to talk about or to discuss papers that have discovered
neurogenesis in the adult brain because
let's be honest what's more exciting than the idea that your brain can
add new brain cells later in life and
indeed that has been shown even in people well into their 80s and 90s. However, it's very important to know that the total amount.
Out of
neurogenesis that occurs in the adult human brain is infinitesimally small
as a mechanism for neuroplasticity and learning as compared to the other forms of
neuroplasticity that we discuss such as long-term potentiation and long-term depression.
So I don't want to you know, throw cold water on the topic of neurogenesis. It's an incredibly interesting and important topic but all too often. They tend to eclipse the much more common mechanism for the formation of short and long-term memories, which are those other
forms. We just talk
Ltp LTD Etc.
So the point here is that yes indeed. There are new neurons that can be
added in the adult
brain maybe even in the adult human brain and there is some evidence that some of those new neurons are added to the hippocampus. In fact a particular region of the
hippocampus called the dentate gyrus of the hippocampus and
there's been a lot of controversy about how much neurogenesis
occurs or doesn't
occur and whether or not occurs after puberty or not. There's a whole field of people battling over this
now for several
decades, but one
NG is very clear neurogenesis while it's very exciting and intriguing is not the main mechanism by which the
formation of short and long-term memories occurs.
When you learn new information, as you are right now the storage of that information in your short-term
memory networks, which is then passed on to your long-term memory networks, and that can be recalled that allows you to State certain facts about for instance. The existence of this thing
called the hippocampus. Hopefully, you will remember that going forward or your ability to perform any kind of motor movement that
Learned now or way back in childhood. Most of that is the consequence of the
strengthening of particular connections and the weakening of other types of connections. Those are the two major forms of
neuroplasticity. Okay, so I don't want you to get the impression that there's something wrong with my memory and that I forgot that this episode is not about shorter long-term memory, but it's about working memory and indeed I have not forgotten. So now is where I tell you why I've been talking about
short and long-term memory and the mechanisms of those because I want them to
To provide a stark contrast
for what we call working memory working memory as far as we know does not involve neuroplasticity or at least if it does it's not a particularly robust
aspect of working memory rather working memory
is the reflection of a particular neural circuit running an algorithm over and over and over for different types of information. But the information isn't stored it is
actually intentionally discarded
now what sorts of
Daily activities and life activities
would require working memory.
The answer to that is basically everything that you need to do, but that you
don't want to remember
now what types of things would those be? Well, let's think about it most all of us learned at some point in our life to tie her own
shoes presumably, you know, how to tie your own shoes. If you don't perhaps you should learn
or where velcro or slippers I don't know but assuming you can tie your own shoes. That's something that you know how to do and you can do it as a procedural long-term memory.
I can do that action. You don't have to think about it too
much working. Memory would come into play when say you wake up in the morning and you know that you need to head out for a jog, but you also need to make a cup of coffee first and you need to remember where the coffee is where your shoes are and perhaps you're making a phone call or you're having a conversation while you need to tie your shoes and so on and so forth working memory is basically the taking in of information that's critical for you to sequence
your actions
over a short period of time and then
Forget that sequence for instance. I'm willing to bet that you put your shoes on to go running before you go
running that's sort of a duh.
And if you're like me you drink your water your coffee your yerba mate before you go running the point here is that if you wake up in the morning and you like caffeine before you go for a run, there are certain
series of action steps that you need to carry out to hydrate make that cup of coffee or tea drink it put on your shoes head out the door. You need to sequence things properly, but you
don't want to commit your
Long term or even your short-term memory stores to carrying out that sequence you simply want to be able to carry out that sequence and then discard that information
about the sequence and focus your attention on for instance what trajectory you're going to run through the park or around your
neighborhood. Then you want to discard that information and you want to lean into the
next portion of your day and so on and so on
in fact working memory is involved in essentially every activity both cognitive and motor from the point you wake up in the morning until the
You go to sleep at night
for every single day of your life and we know this because there are indeed people who have diminished working memory or even lack working memory
entirely. Although the latter is somewhat rare it has happened. And as you can imagine
they have a complete failure of ability to sequence
activities and their lives are extremely difficult. They need a ton of assistance from other people
even more assistance than do people who have minimal or no long-term memory.
Okay. So this is really highlighting just how
important
and working memory is working memory is basically the way that you navigate any immediate
environment. And as I mentioned earlier, it's very closely tied to attention because in order to know what to do now and then what to do subsequently and then subsequent to that
you need to be able to hold your
attention to the things you need to do.
So working memory and attention collaborate literally at a neural circuit level and that a neurochemical level in order to
allow you to move through your day in an Adaptive functional way and people who
have
As with attention or Focus or working memory and sometimes it can be hard to dissociate which one they're having challenges
with really have a hard time moving through life as
compared to people whose
attention and working memory is more robust. Now.
The good news is today. We're going to talk about working memory some of the neural circuits involved and some of the neural chemicals involved
that can augment or improve working memory and we're
also going to talk about what one can do to
directly increase the amount of neurotransmission of those particular chemicals.
Within the circuits that control working memory in other words to improve your working memory.
Now, I can talk about working memory in the mechanisms Etc all day long, but as is often the case, sometimes it's better to not just learn about
Concepts but actually to experience them in real-time. So
what we're going to do now is I'm actually going to give you a working memory test.
This is the sort of working memory test that you would take if you were to go into a psychology laboratory or neuro science laboratory, and they were studying working.
Memory in
humans. Now, there's another advantage to us doing this in real
time right here as you're listening or as you're listening and watching and
that's because you're going to get data you're going to get information about what your Baseline working memory capacity is and you're going to want to keep those data
in your short-term memory stores, maybe even your long-term memory stores, but certainly your short-term memory stores because
shortly later in this episode. I'm going to talk about different ways to improve your working memory depending on where your
Line working memory
start which by the way turns out to be a pretty good proxy for the levels of a neuromodulator called dopamine within the neural circuit that
control working memory.
So right now let's take a working memory task. We're going to do this purely through audio form because I realize some people are watching and listening to this on YouTube
and others are just
listening to this episode. So there are not going to be any visual cues or
slides that I present and that's
perhaps what distinguishes what we're about to do most from what
In a laboratory typically in a laboratory there would be some visual
presentation of what I'm about to say, but here because of the format that most of you are
consuming this information by we're going to do this purely by Audio. So the first test of your working memory is very
simple. I'm going to read off a series of letters
and your task is
to remember as many of those letters as you
can.
the first string of letters is j k z-- p i
Okay, just to make this really
easy. I'm going to say it twice although typically in a working memory task. It would just be said once but I'm going to make this extra easy. J k-- z EP I okay. Now
you and your own head can try and recite
back those letters if
you like.
Okay, second string of letters. Are
o om K KL e
I'm going to make this extra simple and do it again. Not typical for working memory task, but there are some working memory tasks where that happens
are
0 0 m KL e
okay.
Now a third string of letters. This one's going to be a little bit longer so cue up that working memory and attention W. Eh
C QV d n--
I'll repeat that again.
Wa c q
VD n how many of the letters I just read. Can you remember?
Okay, so depending on how many letters you can remember perhaps you have a low moderate or high degree of working
memory.
Keep in mind that some of you are perhaps doing other
things you're attending to driving or other tasks within your home or your office. And so perhaps you weren't able to pay full attention. So there will be some variation there but
nonetheless after reading each of those strings of letters. You were asked to
recall those letters in your mind and if you wrote them down and you're rereading them. Yes that's cheating.
But how about this? What if I were to
ask you now
about the simplest first string of letters the one that consisted of only
five letters
How many of you can remember any of those five letters
now?
Okay, I can't hear you. If you're shouting them out. I can't see you if you're raising your hand
but chances are most of you have
forgotten the first series of
letters, even though it was quite short and you could remember it early on that ability to remember that string of letters when you first heard them and indeed I read them twice. So I'd be very surprised if any of you
couldn't remember that string of letters after hearing them twice, but
I also read you some other letters in the interim. Okay, so that now just a couple minutes later. I'm asking you to remember that first
string.
Of
five letters and assuming that you didn't write it down here not cheating
chances. Are you remember anywhere from 2 to 20 of those letters in that first word, which is a perfect example of your working memory. Nothing got committed to
short-term much less long-term memory rather
your working memory was able to work with that information. Hold it in mind for just as long as you thought you need to know that information, but then thank goodness
that information was discarded. You
didn't know that I was going to
to ask you for that first string of letters again after reading you the longer string of letters, but I did that deliberately to show you how your working memory works. So in some sense the working memory task is
a bit unusual
in that it's a test of yes memory in the very very short term but also a test of
your ability to forget to discard information that's not critical and that gets us back to the original definition of working memory, which is our ability to attend to specific small
batches of information remember it for just as long as we think we need
To and then to
discard that information and by the way, if you want to know what those
first five letters were they
were j k-- z Pi.
I'd like to take a brief moment and thank one of our
sponsors and that's a G1
H. G1 is a vitamin mineral probiotic drink that also contains adaptogens. I started taking a G1 way back in
2012. The reason I started taking it and the reason I still take it every day is that it
ensures that I meet all of my quotas for vitamins and minerals and it in
ensures that I get enough Prebiotic and probiotic to support gut health now gut health is something that over the last 10 years we realized is not just important for the health of our gut but also for our immune system and for the production of neurotransmitters and neuromodulators things like dopamine and serotonin, in other words God health is critical for proper brain functioning. Now, of course, I strive to consume healthy Whole Foods for the majority of my nutritional intake every single day, but there are a number of things in a G1 including specific.
And that are hard to get from Whole Foods or at least in sufficient quantities. So ag-1 allows me to get the vitamins and minerals that I need probiotics prebiotics the adaptogens and critical micronutrients. So anytime somebody asks me if they were to take Just One supplement what that supplement should be I tell them a G1 because a G1 support so many different systems within the body that are involved in mental health physical health and performance to try a G1 go to drink AG one.com
huberman and you'll get a year
supply of vitamin D3.
3K two and five free travel packs of a G1 again. That's a drink AG one.com hubermann. So now's where we talked a
little bit about the neural circuitry and the neurochemistry of working memory. Now, it's
important that we do this because in a few minutes, you're also going to learn that people generally fall
into two broad bins of having a
high or low Baseline of a certain neural chemical in the brain that affords them either high or low working
memory capacity.
Sadee now in reality. It's a distribution. In fact, it's what we call a normal distribution. So it really isn't to bins
but during today's discussion. And in fact in a lot of laboratory
studies we can actually bin people into these two groups the neural circuitry underlying working memory involves a lot of different brain locations. That is a lot of different neural networks collaborating to create this thing. We call working memory. However, there are a couple of key
hubs that is
locations within the brain that are especially important for
King memory
the ones that I'd like to focus on today involve the prefrontal
cortex. So this is neural real estate that resides just behind the forehead and
the neurons in the brain stem. So
further back in the brain that manufacture dopamine and that send
their little wires that we
call axons up to the prefrontal cortex to release dopamine dopamine is a neuromodulator many people are familiar with dopamine and familiar with it in the context of motivation and drive.
Sometimes people mistakenly think it's only involved in pleasure. But dopamine is involved in motivation and drive when dopamine systems go. Awry that is if their levels it
too high that can create manic States. It can create addictive States
when dopamine levels are too low you can get movement challenges such as in Parkinson's which is a deficit or a literal destruction of the neurons that manufacture dopamine there bunch of
different areas of the brain that those dopamine neurons in the brain stem project to but for right now we're going
To focus almost entirely on the dopamine projections from the brain stem to the
prefrontal cortex, which is called the Meisel cortical circuitry.
I'm not going to get into the origins or the meaning of the Miso cortical versus other dopamine projection systems. I did that in a couple of episodes about ADHD and attention and dopamine in particular and you can
find those at huberman live.com just put dopamine and circuits into the
search function and it will take you to those particular
timestamps where I describe that but since we want to keep things,
Fairly top Contour at the level of neural circuitry here.
Just know that there are a bunch of neurons that manufacture dopamine back in the brainstem that send their axons those little wires up to the prefrontal
cortex and that the
amount of dopamine released per unit time. So in a certain amount of time strongly dictates the extent to which working memory
capacity is going to be high medium or low
now, I want to be very clear because I'm going to come back to this a little bit later again and again,
It is the case that when dopamine levels are lower that is either there fewer neurons that have the potential to release dopamine in the frontal cortex or for whatever reason less is being released in the frontal cortex that working memory performance tends to be lower as compared to conditions where dopamine release or the availability of dopamine
is higher. However,
it is not the case that more dopamine is always going to equate to
improved working memory.
This is so important that I'm going to say it again it is not always
The case that increasing the amount of dopamine Transmission in the frontal cortex
leads to improvements in working memory. There is
a specific criteria that allows us to predict whether or not it will improve or maintain or actually degrade working memory performance. So before you head to the end of the podcast to try and figure out ways to increase dopamine to improve working memory, please keep that fact in mind don't just commit to your working memory commit it to your short and long-term memory because that's very important if your goal is to improve your working memory.
With that said I do want to describe just a little bit of research showing the relationship between having a low working memory span as it's called the ability to only remember a few letters or numbers or short batches of
information as compared to a high working memory span meaning longer strings of letters longer strings of numbers,
which of course in the real world translates to being able to
carry out shorter versus longer action sequences as described earlier in the scenario. Where you getting up in the morning you're making coffee and you
Out for run etcetera Etc. People do differ in terms of their working memory capacity and there's a classic study done by cools and Esposito and colleagues. This is published in 2008 where they had a way
to label the amount of dopamine that is available for release in the frontal
cortex in human subjects. They did this by the injection of a
specific dye that dye gets taken up
specifically by the neurons in the brain that manufactured dopamine then they were able to image the brains of those people while those people were Wide Awake
Cake using something called positron emission tomography again. The specific tool isn't necessarily important. But since some of you like to
know and what they found is that for people that had a high working memory span that is could remember long strings of numbers or letters or other information. They tend to be the people that had more dopamine available for release in the frontal cortex either because they had more of the dopamine neurons themselves or similar number of neurons, but those neurons had more dopamine to
Okay, and they also found the converse individuals that had a low working memory span and ability had less dopamine available for release so that establishes a correlation but it's not causal a different study, which is also a classic was carried out by brosky Brown Ross bold and Goldman and this is a really important study because in this study they were able to introduce small amounts of dopamine directly into the cortex and evaluate working memory.
Marie capacity now anytime a working memory test is done the same pattern always emerges. This is regardless of any dopamine being infused into the brain, which is people and
animals for that matter are very good at remembering short spans of numbers letters or other types of information. So if you tell them one thing like the letter a and then you ask them to remember letter almost everybody remembers that but if you give them a
string of ten letters, they remember fewer of
those ten letters that's sort of obvious, but it's important point to emphasize nonetheless. And so there's
And of a dropping off curve of performance, as one progresses
from fewer to Greater number of items to be remembered
in this study when dopamine was introduced to the frontal cortex, the number of things that individuals could remember simply increased. It was a very straightforward result more dopamine introduced allowed longer letter number
and information strings to be remembered and of course forgotten because that's what working memory involves remembering and then discarding.
Of information shortly thereafter
now the findings that I just described compliment what I said before which is the naturally occurring experiment bring people into the lab measure their working memory span. Look at how much dopamine they make higher dopamine better working memory lower dopamine lower working memory the experiment I just described was one in which dopamine is introduced showing that dopamine is very likely the rate limiting or
the capacity limiting probably the better way to put it the capacity
limiting neuromodulator for improving working memory.
That's a fancy nerd speak way of saying more dopamine allows for better working memory
but a critical feature of this experiment is that they did a number of experiments where they didn't introduce dopamine, but instead they introduced other neuromodulators to the
prefrontal cortex such as norepinephrine
or serotonin and the interesting finding is that the addition of norepinephrine or serotonin which of course are other neuromodulators that can change the
firing patterns of neurons.
It's in the prefrontal cortex, but elsewhere as well. It's just that in this case. They were added to the prefrontal cortex
had no effect on working memory. It neither improved nor degraded working memory when those neuromodulators were introduced in other words dopamine and perhaps only dopamine seems to be the dominant neuromodulator for regulating the degree that is whether or not you have small medium or large amounts of
working memory capacity in the prefrontal cortex.
Tax and of course there have been a bunch of other experiments that are worth mentioning briefly in this
context such as taking people that have a
high working memory capacity and indeed have their brains
image and one sees that they have high levels of
Baseline dopamine,
especially the dopamine projecting to the prefrontal
cortex and then they're given a drug that
depletes dopamine within the prefrontal cortex and their performance drops. And so it's so nice about the literature around working memory. Is
that while I'm not covering all of that literature exhaustively it all tends to jibe at all points in it.
Direction where
by the levels of dopamine being released in the prefrontal cortex during working memory tasks correlates, very strongly with capacity to perform working memory task
lower dopamine
lower working memory span as it's called higher dopamine higher working memory span. Okay. So next we're going to
do another working memory test different
than the one we did earlier and we're going to do that with a specific purpose in mind which is for you to be able to determine what your working memory.
Capacity is and by extension
your Baseline levels of dopamine or at least the levels of dopamine that are likely being released into your prefrontal
cortex while you do these working memory tasks. In other words. We're going to try and figure out whether or not you are of the low medium or high working memory capacity. And of course, we're doing that in
part to try and establish whether or not you likely have low medium or high amounts
of dopamine available for release in the prefrontal cortex. Of course, we're not putting you into a positron.
In tomography scanning device we aren't able to do that for obvious
reasons. But keep in mind that what we're about to do is very similar and in some cases identical to laboratory studies where the researchers were trying to determine what people's levels of dopamine within these particular neural networks. We've been discussing the music cortical pathway are likely to be in other words performance on The Working memory tasks that we are about to
do is a decent
indication of what the dopamine levels that are available for lease in your prefrontal cortex.
Caps might be now. I say perhaps might
be because I don't want to cause any unnecessary alarm. If for instance you fall into the low
working memory span group. In fact, if you fall into the low working memory span group, there are actually some terrific tools that you can
use to improve
dopamine Transmission in those Pathways and improve your working memory.
I also don't want people to get the impression that somehow performance on this working memory
task is reflective of some larger dopamine issue in the brain and certainly it is not I repeat. It is not diagnostic.
Of Parkinson's or any kind of neurodegenerative condition. Although I will say that deficits and working
memory are common in patients with
Parkinsons for obvious reasons. Those patients have
deficits in dopamine neurons, not only production, but the number of dopamine neurons,
it's one of the Hallmark features of Parkinson's but also in things like traumatic brain injury
Etc, but the working memory tasks that you're about to take when given to a general population or group of
undergraduates or you know, so-called normals are typical control subjects, which all of you are
So unless you're dealing with a traumatic brain injury, or you know, you have
Parkinsons, we know that the data that you're going to get back right now
is very similar to the data that people get back when they do these sorts of studies in a laboratory.
That is it's typical for some people to have a short working memory span. Some people have a medium working memory span and some people have a
high working memory span. And today we're actually just going to divide into two bins short working memory span and high working memory span and we can have
some degree of
confidence that correlates with the amount of dopamine.
I mean available for release in the frontal cortex,
but and this is a very important Point as we progress along this discussion
of working memory the neural circuits dopamine Etc.
I want to make clear something that I said earlier which is that it is not the case that increasing the amount of dopamine that's available always
increases working memory spent. In fact, there's a common circumstance
whereby people with a relatively High degree of working memory capacity increase their dopamine levels, even further using pharmacology or other methods that will
Gus and their performance
actually can degrade okay. So if any of those confusing
now, we'll make it all very
simple going forward so
that if you decide to implement any of the protocols discussed in this episode
that you are aware of
what you can expect and whether or not you were in the category of people that should or perhaps should not incorporate those protocols. Okay. Let's test your working memory again this time the working memory task is going to be a little bit
different than the one you did previously
this working memory task involves me reading.
It's different sentences to you. And your job is to pay attention to these six sentences
because you're going to be asked some information about these sentences in a few moments.
The first sentence is real estate costs are going
up.
The second sentence
is the Atlantic Ocean is warm in summer.
The third sentence is there's a lot of interest now in electric cars.
The fourth sentence is some reptiles eat only once
a year.
The
fifth sentence is kids nowadays. Look at screens more than 60% of their Waking Life.
And the sixth and final sentence
is football can mean different sports depending on the country.
Okay, so I read you six
sentences. They were
moderately long. I confess your job for the working memory task is now to recall as many of the final words of each of those sentences as you can
I'll give you a few moments to do
that. Now before I tell you what the final word of each of those sentences actually is I want to remind everybody that working memory capacity follows a normal distribution. So some of you will be able to remember the final word.
Perhaps five or even six of those sentences. Although I must say that is exceedingly rare some of you are going to be able to remember three to four of the final words of those sentences and that's more typical that actually represents the
average or the mean as we
call it and then fewer people although still many of you will only be able to remember one or two of the
final words of those sentences.
Okay. So now I'm assuming that most of you have tried to call to memory the
final word of as many of those six
sentences as you can and
maybe written them down or you've typed them into your phone or you have some record of what you recall
those six final words of those sentences are
now I'm going to tell you the actual final word
of each of those sentences
the final word of the first sentence was
up because as you may recall the sentence was real estate costs are going up
the final word of the second sentence was summer
because the sentence was the Atlantic Ocean.
Warm in summer
the final word of the third sentence was
Cars because the sentence was there is a lot of interest in electric cars.
The final word of the fourth sentence
was year
because the sentence was some reptiles
eat only once a year the
final word of the fifth sentence was life
because the sentence was
kids nowadays look at screens more than
60% of their Waking Life
and the final word of the sixth sentence
was country.
Does the sentence was football
can mean different sports depending on the country?
Okay. So be honest with yourself and tell yourself and you don't have to tell anyone else. You don't want to how many of the final words of those six sentences. You could remember
correctly important that you remember them correctly.
Again, the number of words that you can recall that is your working memory span is going to vary from person to person but we can take the normal distribution of those scores it sort of draw a line down the middle and say that if you could remember three to six of
Final words of those sentences correctly you're going to fall into the high working memory span group.
Whereas if you
could only remember one or two or maybe zero of the final words of those six sentences, then you're going to be in the low
working memory span group
again. I don't want to alarm anybody. This doesn't mean that you have any Global memory deficits or dopamine deficits, but it is important especially if you plan to apply any of the protocols to improve working memory that you Faithfully that is you accurately
Lee report your working memory performance at least to yourself now as you recall whether or not you have low or high and here we are just beginning in too low and high there's no medium. We've divided right at that
line. We're saying if you remember 326 recalling that high working memory span at least for this discussion and if you can remember fewer than three even down to
zero of the final words of those senses, that's
low working memory span. We're dividing
into we divided you into two groups, and we do know when this has been done in large numbers of human subjects and
Some in some cases all of those subjects have their brand image for the amount of dopamine available for release
in their prefrontal cortex that
short working memory span correlates with lower amounts of dopamine. Whereas higher working memory span or longer working memory span, whatever you want to call it correlates with more dopamine
available for release in the prefrontal cortex.
Now, this is where things get really interesting and frankly really exciting for everybody, especially
Especially the folks in the low
working memory span group
work from Mart Esposito and colleagues
at UC Berkeley as well. As other Laboratories
have explored the consequences of increasing dopamine levels in the brain of typical populations of individuals. So these are not people with Parkinson's or TBI but undergraduate students, which we do realize is not completely representative of the quote-unquote normal population outside the university, but also people from the community.
People were not University students and so on and
the ways that they've increased dopamine in those individuals had tended to rely on
pharmacology. So these are prescription drugs
that most often have been developed for the treatment of Parkinson's in order to increase dopamine levels, but for some other purposes as well drugs, like bromocriptine, which we know are so called dopamine agonists and antagonists is a drug that has the consequence of increasing the amount of a given neurochemical in this case dopamine whereas an antagonist is a
drug that either blocks or prevents or somehow lowers the total available
amount of a certain chemical such as dopamine or serotonin etcetera. So bromocriptine is a drug that increases dopamine.
So when human subjects came into
a laboratory didn't take
any drug, no bromocriptine yet. And of course they were being evaluated for whether or not they were taking any meds for ADHD their caffeine consumption Etc. There were certain rule ins and rule out for that study, but certainly people that were taking any kind of prescription medication.
ADHD were not included in the study
or were eliminated from the study because those drugs can indeed increase dopamine as well as some other neuromodulators such as norepinephrine and epinephrine. I covered all that and that to ADHD episodes that I did which again you can find it here alive.com just go to the search function put in ADHD in any event
in these studies. They took people that had not taken any drugs to increase dopamine.
Had their working memory measured very similarly to the way that you
measured your working memory a few minutes ago with the six sentence
business that we did and then they took bromocriptine and they either took a low moderate or high dose of
bromocriptine and 90 minutes later. They took a working memory task
and what was observed was very
interesting. You can probably predict what it is based on everything. I've said up until now
individuals that initially had
Low Baseline levels of dopamine and therefore shorter working memory
span. So they only remembered 02 about
three of the final words of that sixth sentence series.
Their performance significantly improved they were able to remember for and in some cases up to six of the final words of those sentences.
Now that is in
complete agreement with everything we set up until now
it simply says that dopamine is
important for working memory. If you start off with lower dopamine stores or dopamine availability for releasing the
prefrontal cortex lower working memory
performance increase
dopamine through ingestion of
bromocriptine,
which is this dopamine Agonist.
All of the circuit changes that we want and would expect to improve working memory occur and indeed
working memory improves very straightforward.
That's interesting. But the even more interesting part of the study is that individuals that already had high working memory span when they took bromocriptine at a low or a moderate dose their working memory did not increase further. Now if somebody was already getting six of the final words of those six sentences. Well, then, of course,
they couldn't improve their performance anymore.
But many of the people in the highwomen
Working memory span group, of course only remembered for and some cases three typically will
be four or five or six of the final words of those sentences
when they took bromocriptine at low or moderate doses their working memory did
not improve significantly. There was
either no change or a very modest change and here's where things get really interesting when individuals who already had a high working memory span
took the highest dose of bromocriptine. And
by the way studies verified that the amount of dopamine
available indeed increased so that was
important to do and they did that.
Well, they're working memory performance actually decreased such that now they had a short or a low working memory span. So what this tells us is that the relationship between dopamine and working
memory follows an inverted U shape functions. Imagine a you and then
just flip it over meaning if you have low dopamine availability in the prefrontal cortex working memory span is
short as you
increase that amount working memory becomes greater, but if you increase the amount of
I mean the prefrontal cortex too much working memory span actually
drops significantly below the Baseline that you started with.
Now this is important for a number of reasons not the least of which is the known relationship between working memory and attention. Now, this is very important to understand in the context of ADHD. But also for people who don't have ADHD and are struggling to maintain focus and attention and carry out working
memory tasks throughout their normal everyday life not in the laboratory, but just moving
going through life because these days we hear a lot a lot a lot
about people struggling with focus and
attention perhaps we don't know perhaps in part due to
overuse of
smartphone social media Etc. Although there's not yet a direct causal relationship that's been established the
data that are emerging suggest that indeed
overuse of those things
can cause problems but
regardless of the source
there does seem to be more ADHD both in kids and an adult and subclinical challenges in focus in
Attention and here's where things get really interesting as it relates to the neural circuitry work from despedido and colleagues and other Laboratories as well have shown
using the similar Paradigm that I described before giving people drugs to increase their Baseline levels of dopamine above
their initial starting point of short or long term memory span capacity
and then had people can perform different types of working memory tasks that tap into two different aspects of
attention and working memory up until now we've been talking about working memory. It's not just one thing.
But working memory actually involves two things or at least two things.
The first is that in order to carry out a working memory
task in to attend to something to really focus.
We need the ability to rule out
distractors. We need to be able
to not pay attention to things
that would otherwise distract Us in addition to that. We need to be able to
switch from one context to the next right making the cup of coffee
to putting on one shoes and heading out the door and in some cases layering different context together talking on the phone while tying one shoes and so
And so forth what this work shows us is that the ability to task switch and context switch that is to shift
around what it is that we're paying
attention to an interleaved different things that we're paying attention to something. That's so critical for moving through our daily lives
is largely dependent on the dopamine projections to a structure in the brain called the
basal ganglia, which is
a structure. I've talked about before on this podcast, but if you didn't hear about it, we can just
broadly Define this structure as being involved in movement generation and stopping.
Movement generation, in fact it's often discussed as the neural circuitry that generates go as in do commands and no go don't do commands.
So the basal ganglia are involved in task
switching and they are involved in task switching in part by sending certain commands to go do certain things and no go to not do other things. Okay task-switching stop doing this start doing that start doing that stop doing this and sometimes to varying extents, right? I mean, we could take
any real-world scenario of time when shoes while talking on
the
And we could micro analyze it in the context of this but I think if you
think about it just a little bit you understand that in order to
perform daily tasks. We need to be able to test which and that's not always a
start one task and start a new task and
oftentimes we're interleaving different tasks to varying degrees. Now the other aspect of working memory and attention is to
eliminate distractions to not pay attention to the irrelevant stuff in one's environment or even the irrelevant stuff on your own
body. Like you can't get distracted by, you know, a
button that you know, my don't be only partially but
And or maybe something a little something on your sleeve if you're trying to do something else at that moment. Okay, and people with ADHD and people who have subclinical challenges and focus
really have a hard time with this right, you know, the
sort of stereotype is you know, the oh look a squirrel that whole thing. But really this typically exist as a more subtle and challenging phenomenon for people where they either can't remember what they were doing or they're simply drawn down different
trajectories different thought trajectories or action trajectories, and then they have a hard time making it
Back to the original thing that they were trying to focus on
and we know based on these studies of dopamine in neuroimaging that eliminating distractors is largely the consequence of
dopamine neurons projecting to the prefrontal cortex. Okay. Now why am I telling you all
this neural circuitry stuff? Well,
yes, there are a bunch of studies showing that if you selectively activate the neurons that send dopamine into the basal ganglia, you improve task switching ability without an improved ability to rule out distractors or if you selectively increase
The amount of dopamine from neurons projecting the prefrontal cortex that you're able to selectively improve the elimination of distractors without improving task-switching ability for practical purposes. And this discussion.
We want to pay careful attention to whether or not the data tell us that those particular protocols those particular approaches are globally increasing dopamine that is increasing the activity of dopamine neurons projecting to the basal ganglia
and the prefrontal cortex or selectively
The basal ganglia or selectively to the prefrontal cortex
and what I can tell you now is that fortunately there are several protocols some of which are behavioral some of which involve specific over-the-counter supplements and some of which involve prescription
pharmacology that
can tap into each of these systems independently as well as globally increase dopamine
to improve focus and working memory at large. I'd
like to take a quick break to acknowledge. Our sponsor element element is an electrolyte drink that has
everything you need.
You need and nothing you don't that means zero sugar and the appropriate ratios of the electrolyte sodium magnesium and potassium and that correct ratio of electrolytes is extremely important because every cell in your body, but especially your nerve cells or neurons relies on electrolytes in order to function properly. So when you're well hydrated and you have the appropriate amount of electrolytes in your system, your mental functioning and your physical functioning is improved. I drink one packet of element dissolved in about 16 to 32 ounces of water when I wake up in the
As well as while I exercise
and if I sweat a lot during that exercise, I often will drink a
third element packet dissolved in about 32 ounces of water after I exercise element comes in a variety of different flavors all of which I find really tasty. I like the Citrus. I like the watermelon. I like the raspberry frankly. I can't pick just one. It also comes in chocolate and chocolate mint which I find it tastes best if they are put into water dissolved and then heat it up. I tend to do that in the winter months because of course you don't just need hydration on hot days.
And in the summer and spring months but also in the winter when the temperatures are cold and the environment tends to be dry. If you'd like to try element. You can go to drink element spelled LMN t.com huberman to try a free sample pack again. That's drink element.com hubermann. Okay. So let's talk about protocols to improve working memory specifically by
way of changing levels of
dopamine in the brain. I've
discussed dopamine many
times before in this podcast. In fact, we have entire episodes devoted.
Optimizing and regulating dopamine and of
course still blooming comes up within the context of the ADHD episodes
and other episodes as well. And again, if you have specific questions about
dopamine or any
other topic for that matter,
if you go to huberman lab.com that website has been engineered so that you can put
one word such as dopamine, but also multiple keywords, so perhaps dopamine exercise or dopamine cold plunge Etc into the search function and it will take you to the specific time stamps of multiple
episodes where those
topics
were discussed
as well as newsletters where some of that information has
been condensed into short PDF form Etc. So we certainly are going to cover some material about improving dopamine for sake of improving working memory now, but if you're generally interested in the science and pharmacology of dopamine and protocols to modulate dopamine levels, all of that can be found at huberman lab.com.
Okay. So let's say you have a short working memory span or a moderate working memory span and you want to experiment with increasing levels of dopamine for sake of improving working memory.
Now, there are a lot of different ways
that we
I
could imagine doing that. Let's start with the behavioral tools known to increase dopamine stores that is shown in
peer-reviewed studies to increase dopamine stores within certain circuits of the brain that are relevant
for working memory performance and the protocol that immediately leaps to mind is the use of certain non sleep depressed protocols. Now non sleep deep rest or NST R is actually a term that I coined because there is a practice that's been established for many hundreds of years called Yoga Nidra, which actually means
yoga
sleep whereby
individuals potentially you if you decide to do them lie down
listen to a script that is listen to an audio script which generally instructs you to do long exhale breathing to deliberately
relax your musculature of your face and of your body and Yoga
Nidra typically also involves
doing certain intentions and the instruction always given at the beginning of Yoga Nidra is that you should try to not fall asleep. Now
some people sometimes fall asleep. Some people don't fall asleep, but the idea and there are data.
Port that Yoga Nidra puts people into kind of a
shallow pattern of sleep certainly not deep sleep and not rapid eye movement
sleep but it's a very interesting and unusual brain state for which we're starting to understand
more and actually have some plans in the not-too-distant future to collaborate with Matthew Walker the author of the book why we sleep and some other colleagues to try and figure out
what exact patterns of neural activity or taking place in the brain and rest of nervous system
during Yoga Nidra
and this
similar protocol which
I call non sleep deep breaths the difference between Yoga Nidra and non sleep deep rest is that non sleep deep
rest doesn't include any of the intentions and removes a lot of the kind of opaque or
sometimes called mystical language from the protocol. Now a
great thing is that Yoga Nidra scripts or protocols as well as NSD our scripts or Protocols are available.
Totally zero cost. You can find them certainly on apps like waking up but also on YouTube for instance if you put an SDR and my last name, there's a 10-minute NST R script there. There are
Lot of Yoga Nidra scripts, if you prefer a female voice
there a lot of different excellent female voices out there one in particular that I like very much is Kelly boys. First-name Kalie lastname Bo Ys she has both Yoga Nidra and then it's the our scripts of various durations of anywhere from eight
minutes all the way out to I believe 45 minutes. Why am I telling you all this? Well, they've been several
studies but in particular one and I do realize we're talking about only one study,
but the results are really intriguing as it relates to what we're talking about today.
In this study they had individuals do effectively in NSD are protocol. They call it Yoga Nidra
and the protocol they used was essentially a Yoga Nidra script. They had people lie
down and listen to a Yoga Nidra
script and to perform Yoga Nidra and
they evaluate it the amount of dopamine available within the brain both prior to
and after performing this Yoga Nidra script
and what they discovered was that after performing a Yoga Nidra protocol the Baseline levels of
I mean that is the amount of dopamine available in the basal ganglia and
a few other structures of the human brain. Of course, these are
humans was increased by as
much as 60 percent
as compared to individuals that did a
different protocol not Yoga Nidra, not an SDR
now did that study
evaluate lots of different
durations of Yoga Nidra AK and Str
know they looked at fairly long h plus Yoga Nidra sessions.
However, there's
some other data that have explored Yoga Nidra AKA and Str
in the context of cognitive
performance and a few other circumstances all of which points to the fact that
cognitive performance and in
particular cognitive performance tasks that have a working memory element to them. And so they weren't the
exact working memory tasks that you did earlier, but they
have a working memory element to them that is subjects had to
keep certain small batches of information in mind and then discard that information in order to be able to perform the task. Well,
although show
Significant improvements in task performance. So while something like NST R Yoga Nidra, it might sound kind of mystical or kind of
you know, wishy-washy or I guess says the kids say weak sauce to some
of you it is anything but weak
sauce. It is really powerful
stuff and it's powerful stuff as it relates to the very neurochemicals and neural circuits
that are involved in working memory.
So if I were to take a step back and just say, okay, what are some zero cost very low if any risk
protocols that one could perform in order to improve
dopamine levels without having to ingest anything take anything really do much of anything at all, except lie there do this progressive muscle relaxation.
There are a few other things involved
in NST r as well, which you'll learn if you decide to try them and improve
or increase the levels of dopamine availability
in the brain
significantly. Well then SDR in Yoga Nidra really are the first
line tools if one wants to do that. I think it's reasonable to say that as I
mentioned before there's no reason to think
There's any risk of doing an Str. Yoga Nidra provide that you're lying down in a safe place as opposed to like in the middle of the road or something,
but assuming you do it in a safe location. I would
encourage you to try it
for really for 20 to 30 minutes when you first explore it perhaps you do longer although I personally have a hard time doing long Yoga Nidra scripts regularly
of full hours a big commitment. I don't generally have that much time.
I often will do a 10-minute and Str. Have there been brain Imaging experiments done for each and all of
Of these Yoga Nidra scripts to determine the
amount or if there's any dopamine increase within the brain. No, but I think
that we can safely
extrapolate from that wonderful
study out of Scandinavia that showed that when human subjects do this Yoga Nidra
protocol that there's a significant increase in Baseline dopamine levels
within key neural structures that relate to working memory. Now many of you have perhaps heard that getting in a cold plunge or taking a cold shower or provided you can do it safely getting into a cold ocean or a cold lake can significantly
Can we maybe even double or even triple your circulating dopamine
levels and indeed that is
true. It has been shown that when people get into cold water typically up to their neck and that cold water by the way can range in temperature anywhere from low 40s to low 60s, depending on how long you stay in that there is a significant increase in the so-called circulating catecholamines. What are the catecholamines the catecholamines our dopamine norepinephrine and epinephrine now the evidence for the cattle?
Lamine increase in response to cold water mainly stems from two studies and in particular one and in that particular study, they had people get
into I wouldn't say super cold water was in the low 60 degrees. And by the way, I'm speaking in Fahrenheit
here and they had those human subjects
submerged in water up to their neck. I think they actually had them sitting in lawn chairs on the bottom of a pool, but again their heads were above water so they could breathe and they stayed in for quite a long while 45 minutes or longer and it was observed that there was
a
Big statistically significant
increase in epinephrine norepinephrine and dopamine that lasted several hours or more. This is one of the reasons why if you've ever done deliberate cold exposure as it's called
it often is uncomfortable when you get in but then when you get out you feel different you feel really good in most
cases provided if you're me you take a warm shower afterwards. Yes. I like to do that. I realize if you want to increase your metabolism, perhaps it's better to not warm up afterwards. I like a nice warm shower or to get in the Saint afterwards. That's just me, but nonetheless.
Deliberate cold exposure clearly induces a
state shift of mind and body that most people
provided they do it correctly and they don't go into water. That's far too cold for them for too long. They report as pleasant. And I think it's reasonable to assume that some of that is the
consequence of these increases in catecholamines, which is why many people opt for a cold shower, which if you're me cold shower followed by a warm or hot shower or a cold Plunge in the morning or maybe even just once or twice a week many people like them typically people like getting out of
And the feeling that they have after they do them on the some of you sickos really like the feeling of getting in and being in it, but not me the point here is that if we were to take a look at the
landscape of zero-cost Behavioral
Tools, in fact behavioral tools that could potentially save you money meaning reduce your heating bill
that are known to increase the very neurochemicals AKA dopamine that are involved in improving working memory. I think it's reasonable to assume
that a cold shower about
30 to 60 minutes prior to doing any kind of work.
In memory tasks or
any kind of activity that would require
increased Focus could be. Okay. We don't know the specific Studies have not been done but
could be in theory. It makes sense mechanistically. It's logically sound
could be done after deliberate cold exposure and indeed many people report not just feeling a bit of you
know mild Euphoria or feeling good after deliberate cold exposure, but also an increased capacity to focus in
fact so much so that a lot of people who do deliberate cold exposure say that they don't
require as much caffeine in order to maintain their
Alertness and energy which
shouldn't be surprising to us at. All.
Right. I mean it's increasing catecholamines. We know this. So that's another protocol that you could explore as well. Is there an important difference or not between deliberate cold exposure done by cold shower or deliberate cold exposure in a cold plunge or the ocean?
Frankly there? Haven't been a lot of studies comparing those but
I think it stands to reason that if you have access to a cold plunge or a cold body of water that you can safely get into up to your neck for 30 seconds to a minute if it's 50 degrees or less.
Right, if you get in colder water, we know for instance if you get into say 45 degree water and you only get in for 30 seconds,
you're going to get a big increase in the catecholamines
perhaps as big as the catecholamine increase that you would get from being in
60 degree water for 45 minutes. Most people don't have 45 minutes to sit around in water up to their neck. So most people opt for 30 seconds
to
as much as three minutes deliberate cold exposure in a
shower or cold plunge or other body of water can only do this if you can do it safely never ever.
Please
for the love of God, please never ever do any kind of
hyperventilation breathing or breath-holding while doing deliberate cold exposure because you can pass out you can die. Don't combine breathwork and deliberate called exposure just don't separate those two things completely.
Okay, but deliberate cold exposure we know is a very
reliable way to increase the catecholamines which includes dopamine. So if you
want to explore deliberate cold exposure
protocols, we get into the Nuance of temperature and duration Etc. You can find
that completely zero Costco to Huber.
And labs.com go to the menu tab scroll down a newsletter and go to the cold exposure newsletter where it details all of that in short PDF form.
Now, some of you are probably asking hey, what if I was in the high or long working memory span group
I ought to have high Baseline levels of dopamine. Should I not do Yoga Nidra or an Str? Should I
not do deliberate cold exposure? Well there you're just going to have to experiment again. There's
essentially zero risk to doing Yoga Nidra and SDR as I
For deliberate cold exposure. There's always some risk getting into water cold water. People always want to know how cold well the newsletter gets to this, but I'll just tell you right now as well. The ideal temperature is the temperature that you can safely get into and stay in for a duration of 30 seconds to 3 minutes before getting out some people off to go longer but I think 30 seconds to 3 minutes is a good
duration to work with for most people especially if you're going to do it frequently so that temperature should be safe for
you to stay in for that duration, but uncomfortable enough
that there's some impulse
to want to get out that you have to work to stay in there and you have to kind of overcome that adrenaline release and the impulse to get out. Okay. So for some
people that's going to be 45 degrees for some people be 40 degrees. It depends on how cold adapted you
are depends on how rested you are. There is no specific temperature you have to really gauge for yourself and so err on the side of caution and you can experiment provided you experiment within the margins of
safety. So if you found during the working memory tasks that you took today that you have a very good working memory. I don't think there's any reason to
Avoid Yoga Nidra NST R and deliberate cold exposure. In fact, there may be reasons to increase your dopamine and other catecholamines
by way of NS. ER Yoga Nidra deliberate cold exposure perhaps for working memory performance. Maybe it could increase further
perhaps it would decrease performance in which case
there. You got your answer. You don't have to
do those protocols again and you certainly wouldn't want to do them
before anything that involves a lot of working memory and attention. But of course those protocols have other benefits as
well. So there's no reason to avoid them entirely just
perhaps avoid them within the context of
trying to improve working memory. However, if you're somebody that has challenges with working memory challenges with attention challenges with Focus.
Well, then I think that the protocols have been talking about up until
now would be an
excellent first foray into the sorts of things that you could do to
increase dopamine. And of course those other catecholamines
as a way to see whether or not it
augments your focus and attention and working memory capacity. Now, some of you are probably shouting shouting shouting what about exercise doesn't
exercise increase dopamine it does. Yes.
Other things that increase dopamine it's not just exercise. There are activities that increase dopamine. Some people are probably saying wait doesn't playing video games increase dopamine sex increases dopamine chocolate increases dopamine? Yes. Yes indeed. Those things can
increase dopamine.
What's interesting and important about the protocols. I've been
talking about. However
and Str Yoga Nidra deliberate cold exposure
is not just that they
increase dopamine but the
duration over which they increase dopamine. Okay,
this is very important if you want to understand more about the
relationship between do
Dopamine Spike says they're called and dopamine Baseline
and why I'm emphasizing these tools that cause large long lasting increases in Baseline dopamine check out the episodes. I did on
optimizing dopamine. We've got a link to them in the show no captions. Now before
I talk about other ways to increase dopamine for sake of improving working
memory is like over-the-counter supplements, like l-tyrosine mucuna purine
things like that. I do briefly want to mention and I promise
briefly. I know sometimes I say briefly and then I spend 20 minutes telling you
about something.
But very briefly. I just want to spend two minutes telling you about protocols that we do not yet know whether or not they increase dopamine levels, but we do know that they
improve working memory because after all this episode is about working memory not just about dopamine and working memory. It has been shown that the
use of binaural beats. Okay binaural beats being the presentation
or the listening to sounds of different frequencies in the two ears typically by headphones that's been shown to work
best and
There's a subtraction between the two frequencies such that the brain tends to in train
or start to follow a particular frequency within not the entire brain, but certain neural
circuits. So if you've heard of say
15, Hertz binaural beats are 40 Hertz binaural beats, that doesn't mean that you listen to a 15 Hertz sound or 40 Hertz sound you listen to two different frequencies of Sound by Hertz is just a measurement of sound
frequency in each of the two ears and then the
difference between them is 40 Hertz or 15 Hertz
and there are several studies that show
Not enormous. Okay. I want to be clear small to moderate
improvements in working
memory performance. But in some
cases significant Improvement and
I'll provide a link to these two
papers in the show not captions, but I'll
just briefly describe them by
way of their title and their major conclusions.
The first is a study entitled the effects of binaural and Montero beat stimulation on cognitive functioning in
subjects with different levels of emotionality a really interesting study published in
2019. It was a relatively small number of subjects only 24
participants 16 males eight males.
Between 19 and 31 years
old listen to these 40 Hertz binaural beats. And by the way, it's very easy to find
apps and other sources of 40 Hertz binaural beats at zero cost or nominal cost out there. You can simply look for 40 Hertz binaural
beats and looked at performance on working memory tasks
as well as some other cognitive
tasks and found in some cases a small to moderate but significant
Improvement in cognitive performance on working memory tasks the aspect of the study looking at emotionality.
He did not find a significant
effect. So it doesn't seem that emotionality
impacts things there. But nonetheless that's study plus the other one entitled the effect of
binaural beats on visual
spatial working memory and
cortical connectivity. This was a study published in 2016
found generally something similar in this case. There were using
15 Hertz binaural beats and here I'm paraphrasing
produced network activity characteristic of high information
transfer with consistent connection strength. What they're really talking about is
is changes in neural activity patterns within the brain that led to or at least were correlated with improvements on visual spatial working memory visual spatial working memory tasks are different than the working memory tasks that you performed earlier
visual spatial working memory
tasks involve the cognitive generation that is within your head of the so-called visuospatial sketchpad. So it's this idea that you see something and then you got a sketch it out in your mind. You have to know the relationships between things in space pay attention to what they are keep those in mind again because it's working.
We just as long as is necessary to perform a task. That's what visual spatial working memory is as you can imagine it translates to an enormous number of everyday activities required for focus and attention and learning and performance and indeed
15 Hertz binaural beats was able to produce
a small but significant Improvement in that sort of working memory test. So
I want to emphasize again. We don't know the
relationship between binaural beats and dopamine at least not from these studies, but I felt I'd be remiss if I didn't mention
mention these two studies that show
that 40 Hertz binaural beats 15 Hertz binaural beats can indeed
improve working memory performance and in these sorts of scenarios
individuals are listening to the binaural beats while
they are doing the working memory tasks and in some cases before they are doing the working memory task either seems to work. It depends on the study there bunch of other studies,
but I thought I'd mention binaural beats because I know a
number of people are interested in them again,
nonpharmacologic zero cost because you can find tools for
Normal, Beat Generation zero cost out their approaches
to improving working memory. Okay, what about over-the-counter compounds that are known to increase circulating dopamine that can potentially improve working memory and that indeed have been shown in peer-reviewed studies to improve working memory by way of increasing circulating presumably brain levels of dopamine. Well, I can think of two specific categories of supplements that is over the counter compounds that at least at this point in time or legal in the United States.
That can increase dopamine levels those two are l-tyrosine, which is an amino acid precursor to
dopamine and mucuna pruriens, which is a believe it or
not. It's the velvety Bean or the outer component of this velvety being that contains or is equivalent to 99%
L-dopa. L-dopa is a key component in
the biochemical Cascade leading to the production of dopamine. In fact, l-dopa is often prescribed for Parkinson's patients.
As a means to increase the dopamine levels, there are at least
three studies that I am aware of of the
use of mucuna pruriens to increase dopamine for the treatment of Parkinson's in other words mucuna pruriens increases dopamine levels. And yes, it has been shown to improve some of those symptoms of Parkinson's patients. We're
not talking about treatment of
Parkinson's today. I want to caution people against any sort of use of supplements to treat Parkinson's or other conditions without consulting your doctor, right? That's very very critical to point out if we're talking about ways to increase dopamine.
Mean for sake of improving working memory by way of supplementation. I think we should start with l-tyrosine because
l-tyrosine unlike mucuna pruriens is a bit further up actually its way further
up the biochemical Cascade leading to dopamine production. However, it has been shown in several studies that l-tyrosine supplementation can indeed increase dopamine
and moreover and here I'm
quoting the title of a study published in 1999, which I realize is a few years back, but of course, there's some excellent studies from a few years back or more
tyrosine.
Proves working memory and a multitasking environment. Now this particular study from Thomas at all has
some interesting aspects and some aspects that made me go a little bit wide-eyed but not necessarily wide-eyed because the
results are so dramatic. In fact, when one looks
at all of the data in this paper, what you find is that supplementing with l-tyrosine as
they did in this study did indeed lead to improvements in working memory under multitask conditions as the title suggests
those improvements were significant, but they weren't enormous. Okay, there was
Statistically significant,
but they were not enormous increases now what was enormous and the reason I got wide-eyed and still get wide-eyed is that the dosages of of l-tyrosine used in the study are really big they had subjects take 150 milligrams per kilogram of L. Crystalline tyrosine. I have them take it an apple sauce for whatever reason or Placebo and they did a number of different control conditions to make sure that whatever effects of l-tyrosine they observed were. In fact due to Bell Tower.
In supplementation. Why am I going wide eyed When I See This 150 milligrams per kilogram of tyrosine.
Well, I weigh 220
pounds. So that's about 100 kilograms. So if I weigh 100 kilograms and it's 150 milligrams for every kilogram, that
means that if I were a subject in the study that they would give me
fifteen thousand milligrams that is 15 grams of l-tyrosine prior to doing these cognitive.
Of task now 15 grams of tyrosine to me
seems like a very very
high dose and I frankly can't in good conscience recommend that why well, maybe I'm just hypersensitive to l-tyrosine. But I've taken 1000 or 1500 milligrams of l-tyrosine and I've definitely experienced an increase in alertness from taking 1.5 G not 15, 1.5 grams of l-tyrosine. And in fact at a subjective level, I can feel a
meaningful increase in alertness and
Focus
from 500 mg of l-tyrosine so I can't in good conscience suggest that people replicate the exact dose protocols within the study nonetheless the study as the title suggests shows that supplementing with l-tyrosine can indeed increase working memory capacity, especially in a multitasking environment, which in many ways carries over
to the sorts of requirements for working memory and attention
capacity to get through life in a very focused for lack of a better word way in a very regimented do this do that task switch.
Multiple things interleaf that's what moving through one's day or at least work day or anything that requires cognition and focus entails.
So first of all, I'll just say what I always say when discussing any kind of
compound or prescription drug never add or
remove any supplement from your supplement
regimen if you have one without consulting with your health provider first to make sure that you are safe to take that particular supplement now many Physicians MDS are not
familiar with most supplements. So you'll probably need to bring some literature
to the phone call or to the visit but
First there are many Health Care Providers including some MD's that are open to
supplementation. Especially these days as supplements have become I would
say generally more accepted. I mean there are certain ones like vitamin
D3 that and fish oils and
things like that that are more common than l-tyrosine but there are many Physicians who are
open to discussions about supplements such as l-tyrosine. If you know that you can supplement with l-tyrosine safely and you opt to do so. What dosages would you potentially take? Well here we have to
Look at the dosages using these studies. I think it's only fair. It's only safe that we acknowledge that these dosages are really really high and I think the logical the safe thing to do would be to start with the minimal effective dose. So if you weigh 50 kg rather than start right off with, you know, the equivalent dosage to this study. Maybe you
start with 250
milligrams of l-tyrosine if you weigh a bit more like me or 100 kg or 75 Kg, maybe you take 500 mg of l-tyrosine and see whether or not
Experienced a significant effect on working memory attention and
performance. So the idea here is to establish the minimal effective dose. I should also point out that some people not all but some people experience a bit of a
crash after l-tyrosine supplementation such that they
feel more alert more focused better ability to
perform working memory tasks move about their day, but then three or four hours later experience kind of a drop.
So you need to be mindful of that. In fact, you need to be mindful of any kind of
pharmacology where you're increasing dopamine. This is one of the reasons why I like the behavioral protocols that we talked about earlier because they're known
own to
create big but
long-lasting and slowly tapering off increases in dopamine another catecholamines
now for those who are curious about
and perhaps even want to try mucuna pruriens, please absolutely talk to your doctor first mucuna pruriens
is essentially the equivalent of l-dopa. L-dopa is a
prescription drug as I mentioned before and mucuna pruriens potently increases dopamine
what dosages of mucuna pruriens can increase dopamine. Well typically in studies of Parkinson's patients, but
So studies exploring typical people who don't have Parkinsons in
cognitive tasks or in sports performance have
explored anywhere from 1 to
5 grams of mucuna pruriens mucuna pruriens again is a very potent way to increase dopamine and here if your healthcare provider approves it and you decide to try it. I would suggest starting with a very very low dose again to find the minimum effective dose it maybe even just 500 mg not even going to the one gram dose maybe even 250 mg and really evaluating how much milk
In your parens can produce a meaningful impact on working memory and attention for you. So mucuna pruriens is kind of a bridge between over-the-counter supplements and prescription drugs. I say it's a bridge because it is O so similar to that prescription drug l-dopa, and of course there
is a long
list of prescription drugs that are known to be dopamine agonists several of which many of which in fact have been shown to improve working memory. You already learned about one of those before which is bromocriptine. Now, you need a prescription from a physician.
Get bromocriptine but
bromocriptine. We know based on that work from despedido and colleagues that I talked about earlier increases dopamine it does so in about 90 minutes it achieves Peak levels of dopamine about 90 minutes and improves working memory in individuals that start off with a low working memory span and we know from
neuroimaging. Those are the individuals with lower Baseline levels of dopamine. So should
you run out and ask your doctor for bromocriptine? Maybe
most doctors won't prescribe bromocriptine for that reason.
I should mention that word from
Ito lab and other Laboratories has shown that one of the Hallmark features of traumatic brain injury, especially frontal lobe injury as well as
certain neurodegenerative conditions, like Parkinson's but other forms of dementia as well as
ADHD involve
deficits in working memory and attention, which makes sense given what we know about the symptoms of those conditions
and that bromocriptine has been prescribed off-label
for the treatment of those conditions to some degree of success. However, those are off labels.
Stands right now as far as I know bromocriptine is not prescribed specifically for those conditions at a kind of whole population level. It's not one
of the drugs on the lookup table
for ADHD or TBI, but certain well inform neurologists and Physicians do prescribe it for that reason. There are other dopamine Agonist that are relevant in this context the ones I think most of you will be familiar with are the drugs that increase dopamine and norepinephrine for the treatment of ADHD,
and I did an entire episode of the human
live podcast.
Just about those compounds things like Adderall things like Ritalin which by the way is quite different than Adderall in terms of how much dopamine relative to norepinephrine. It causes the increase of I
cover all that in those
episodes and you can simply go to huberman labs.com put ADHD Adderall or ADHD Ritalin and I talked about other things as well. I also took a little bit about modafinil, which is a entirely different category of drug known to improve cognitive performance in some cases in ADHD, but in everybody
so there are a lot of different
Drugs that can improve working memory most of those do so by increasing transmission of dopamine or availability of dopamine somehow
changing dopamine levels in the brain by increasing them. So if you're somebody that has challenges with working memory focus and attention,
please see those episodes and
please talk to your doctor about potentially using pharmacology to increase dopamine. However, and this is very
important many people who have challenges with Focus
attention and working memory and
and fall under the category of subclinical levels of ADHD and even some individuals with ADHD
young and old manage their symptoms and in some cases improve their focus through the use of Behavioral tools nutritional tools supplement based Tools in ways that
either allow them to reduce their total prescription drug dosages and in some cases come off them entirely now, I'm definitely not saying that people should come off those drugs entirely. And in fact, I want
to take a really firm stand here
because I know this is a bit controversial, but I'm just going to tell you
Having evaluated
the whole literature several times over
now. I do think I personally believe that there is a strong case for certain children and adults to take these compounds that increase dopamine and epinephrine. Yes, those compounds are different forms of amphetamine,
but those compounds we know can
increase neuroplasticity the rewiring ltp LTD
Etc within the neural circuits that control Focus attention and working memory.
And so they
Do have their place for certain individuals? We don't want to rule those out. Are they over
prescribed? My feeling is that yes, they are probably over prescribed. However, there are a number of individuals that
strongly benefit from them as well.
So if you are going to explore the use
of those compounds for sake of improving working memory, certainly if you're going to explore them for sake of improving working memory and focus and young kids, please please
please talk to your
physician because their prescription drugs you would need to talk to a
physician anyway, but regardless of whether or not you're trying to improve
focus and work.
Memory in a child in an adult someone with TBI someone with Parkinson's I think it stands to reason that you would arrive to that conversation with some knowledge of not just the prescription drugs that are potentially available. But also some of the supplement based tools some of the behavioral tools because as we know and as a good friend of mine who is an excellent physician says Better Living Through Chemistry still requires Better Living meaning yes prescription drugs can have a positive impact on these aspects of brain function in a way that can really
we improve lives but that behavioral tools also work. In fact, they can collaborate in a very synergistic way to increase the amount of neuroplasticity in the relevant circuit. So I'm of the mind and I think more and more people out there. I like to think are of the mind that behaviors
nutrition supplement based tools
and prescription drugs all can have their place to varying degrees depending on the circumstances and the individual.
Okay. So today we talked about working memory this incredible
capacity of our brain in
fact
A specific set of brain circuits designed for us
to absorb information that is perceived in our environment use the relevant parts and then Chuck it just get rid of it. Forget it
so very different than short and long-term memory
which we also discussed and we talked about a few of the mechanisms as well. I
think you'll agree that working memory is one of
the more incredible aspects to brain function. I mean if you think about this is a set of neural circuits that engage the same
algorithm over and over in different contexts in order for us to be able to
Navigate new environments
familiar environments to interleave different activities different strategies to tasks which to rule out distractors. It's
also critical to every aspect of our
Waking Life and fortunately there are also zero cost and low cost behavioral supplement based and prescription drug approaches to improving this incredible thing. We call working memory. So it was a pleasure to share some of those with you today as well.
If you're learning from and you're
enjoying this podcast, please subscribe to our YouTube channel. That's a terrific.
Zero cost way to support us
in addition, please subscribe to the podcast on both Spotify and apple, please also check out the sponsors mentioned at the beginning and throughout today's
episode. That's the best way to support this podcast.
If you have questions for me or comments about the
podcast, we're guess or
topics that you'd like me to host on the huberman Lab podcast, please put those in the comments
section on YouTube. I do read all the
comments during today's episode and on many previous episodes of The huberman Lab podcast, we discussed supplements while supplements are necessary for everybody many people drive.
Tremendous benefit
from them for things like improving sleep for hormone support and for Focus
to learn more about the supplements discussed on the huberman Lab
podcast, you can go to live momentous spell do u.s.
So that's live
momentous.com hubermann.
If you're not already following me on social media. I am huberman lab on all social media platforms. So that's
Instagram Twitter now called X
threads Facebook and Linkedin on all of those
platforms. I discuss science and science related tools
some of which overlaps with the content on the huberman Lab podcast, but
much of which is distinct from the
Content on the huberman Lab podcast
again, that's huberman lab
on all social media platforms.
If you haven't already subscribe to our monthly neural network newsletter, the neural network newsletter is a completely
zero cost newsletter that
provides podcast summaries and protocols in the form of brief PDFs of one to three pages in which I detail things like how to do deliberate cold exposure and some of the science behind it how to regulate your dopamine levels how to improve your sleep and on and on everything from Focus
neuroplasticity and all of which is available again
completely zero cost.
By going to huberman lab.com go to the menu tab scroll down a newsletter and simply sign up by providing your email, and I want to emphasize that we do not share your
email with anybody.
Thank you. Once again for joining me for today's discussion about working memory and ways to
improve your working memory and last but certainly
not least. Thank you for your interest in
science.
