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Welcome to The Huberman Lab podcast, where we discuss science and science-based tools for everyday life.
I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today we are going to talk all about dopamine and what drives you to do the things that you do. We're going to talk about motivation and desire and craving, but also how dopamine relates to satisfaction and our feelings of well-being. And of course, any discussion about dopamine has to include a discussion about the potential for dopamine-induced addiction. Indeed, dopamine lies at the heart of addiction to all things, but today we are mainly going to focus on how what we do and how we do it, and how we conceptualize those things, leads to changes in this amazing molecule in our brain and bodies that we call dopamine. I'm going to teach you what dopamine is and what it is not.
There are a lot of myths about the molecule dopamine; we often hear about so-called dopamine hits. Today we are going to dispel many common myths about dopamine, and we are going to talk about how dopamine actually works. We're going to discuss the biology of dopamine, the psychology. We will discuss some neural circuits and a really exciting aspect of dopamine biology or so-called dopamine schedules. In other words, we are going to discuss how things like food, drugs, caffeine, pornography, even some plant-based compounds, can change our baseline levels of dopamine. And in doing so, they change how much dopamine we are capable of experiencing from what could be very satisfying events, or events that make us feel not so good because of things that we did or took prior. So I promise you it's going to be a vast discussion, but I will structure it for you, and you'll come away with a deep understanding of really what drives you. You will also come away with a lot of tools, how to leverage dopamine so that you can sustain energy, drive and motivation for the things that are important to you over long periods of time.
Before we dive into the meat of today's discussion, I'd like to share with you a fascinating result that really underscores what dopamine is capable of in our brains and bodies, and underscores the fact that just through behaviors, no drugs, nothing of that sort, just through behaviors we can achieve terrifically high increases in dopamine that are very long and sustained in ways that serve us. This is a result that was published in the European Journal of Physiology. I'll go into it in more detail later, but essentially what it involved is having human subjects get into water of different temperatures. So it was warm water, moderately cool water and cold, cold water. Had them stay in that water for up to an hour, and they measured by way of blood draw things like cortisol, norepinephrine and dopamine.
What was fascinating is that cold water exposure led to very rapid increases in norepinephrine and epinephrine, which is also just called adrenaline. It also led to increases in dopamine, and these increases in dopamine were very significant. They kicked in around 10 or 15 minutes after submersion into the cold water. And I should mention the head wasn't below water, it was just up to the neck. And the dopamine release continued to rise and rise and rise, and eventually reached 250% above baseline.
Now, what was interesting is after subjects got out of this cold water, that dopamine increase was sustained. And I know nowadays many people are interested in using cold water therapy as a way to increase metabolism and fat loss, but also to improve sense of well-being, improve cognition, improve clarity of mind. There's something really special about this very alert but calm state of mind that seems to be the one that's optimal for pretty much everything except sleep. But for all aspects of work and for social engagement and for sport, that highly alert but calm state of mind really is the sweet spot that I believe most of us would like to achieve. And this cold water exposure, done correctly, really can help people achieve that state of mind through these increases in dopamine that last a very long time.
I will later detail the specifics of that study, what it entailed in terms of how long the variations that different subjects experienced, as well as how to limit the amount of stress hormone, cortisol, that's released as a consequence of the cold water. And we will also talk about compounds, supplements that people can take in order to increase their levels of dopamine, should they choose.
Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is however 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.
I'd like to announce that there's an event that some of you may find very useful. This is an event put on by Logitech that I will be speaking at. It's called Rethink Education: the Biology of Learning, Re-Imagining Learning through Neuroscience. And at this event I will be speaking, there will be other speakers as well, and I will be talking about neuroplasticity and its applications for teaching and for learning. I will describe what I call the plasticity super-protocol that incorporates all of what we know about rapid learning, efficient learning, and the best ways to teach and learn. It's geared towards educators of all kinds. It is zero cost. So please feel free to sign up. The event is September 30th, 2021, at 3:00 p.m. eastern. You can find the registration link in the caption for this episode.
So let's talk about dopamine. Most people have heard of dopamine, and we hear all the time now about dopamine hits, but actually there's no such thing as a dopamine hit. And actually, the way that your body uses dopamine is to have a baseline level of dopamine, meaning an amount of dopamine that's circulating in your brain and body all the time. And that turns out to be important for how you feel generally, whether or not you're in a good mood, motivated, et cetera. And you also can experience peaks in dopamine above baseline. Now, this has a very specific name in the neurobiology literature, so-called "tonic" and "phasic" release of dopamine. And I'll explain what that means in a couple of minutes. But if you remember nothing else from this episode, please remember this. That when you experience something or you crave something really desirable, really exciting to you, very pleasurable, what happens afterwards is your baseline level of dopamine drops. So these peaks in dopamine, they influence how much dopamine will generally be circulating afterward.
And you might think, "Oh, a big peak in dopamine. After that, I'm going to feel even better because I just had this great event." Not the case. What actually happens is that your baseline level of dopamine drops, and I will explain the precise mechanism for that. In the neuroscience literature we refer to this as tonic and phasic release of dopamine. Tonic being the low level baseline that's always there circulating, released into your brain all the time. And then phasic, these peaks that ride above that baseline. And those two things interact, and this is really important. I'm going to teach you the underlying neurobiology, but even if you have no background in biology, I promise to make it all clear. I'll explain the terms and what they mean, and I'm excited to teach you about dopamine because dopamine has everything to do with how you feel right now as you're listening to this. It has everything to do with how you will feel an hour from now, has everything to do with your level of motivation and your level of desire and your willingness to push through effort.
If ever you've interacted with somebody who just doesn't seem to have any drive, they've given up, or if you've interacted with somebody who seems to have endless drive and energy, what you are looking at there in those two circumstances is without question a difference in the level of dopamine circulating in their system. There will be other factors too, but the level of dopamine is the primary determinant of how motivated we are, how excited we are, how outward facing we are, and how willing we are to lean into life and pursue things.
Dopamine is what we call a neuromodulator. Neuromodulators are different than neurotransmitters. Neurotransmitters are involved in the dialogue between neurons, nerve cells, and neurotransmitters tend to mediate local communication. Just imagine two people talking to one another at a concert. That communication between them is analogous to the communication carried out by neurotransmitters, whereas neuromodulators influence the communication of many neurons. Imagine a bunch of people dancing where it's a coordinated dance involving 10 or 20 or hundreds of people. Neuromodulators are coordinating that dance. In the nervous system what this means is that dopamine release changes the probability that certain neural circuits will be active and that other neural circuits will be inactive. So it modulates a bunch of things all at once. And that's why it's so powerful at shifting not just our levels of energy, but also our mindset, also our feelings of whether or not we can or cannot accomplish something.
So how does dopamine work and what does it do?
Well, first of all, it is not just responsible for pleasure. It is responsible for motivation and drive, primarily at the psychological level, also for craving. Those three things are sort of the same. Motivation, drive and craving. It also controls time perception, and we will get deep into how dopamine can modulate time perception and how important it is that everybody be able to access increases in dopamine at different time scales. This turns out to be important to not end up addicted to substances, but it also turns out to be very important to sustain effort and be a happy person over long periods of time, which I think most everybody wants. It certainly is adaptive in life to be able to do that.
Dopamine is also vitally important for movement. I'll explain the neural circuits for dopamine and mindset, and dopamine in movement, in a moment. But in diseases like Parkinson's or Lewy body dementia, which is similar to Parkinson's in many ways, there's a depletion or death of dopamine neurons at a particular location in the brain, which leads to shaky movements, challenges in speaking, challenges in particular in initiating movement. And because dopamine is depleted elsewhere too, people with Parkinson's and Lewy body dementia also experience drops in motivation and affect, meaning mood. They tend to get depressed, and so on. When those people are properly treated, they can, not always, but they can recover some fluidity of movement, some ability to initiate movement. And almost without question, those people feel better psychologically, not just because they can move, but also because dopamine impacts mood and motivation.
What are the underlying neural circuits?
For those of you that are not interested in biology and specific nomenclature, you can tune out now if you want, but it's actually pretty straightforward. You have two main neural circuits in the brain that dopamine uses in order to exert all its effects. The first one is a pathway that goes from this area in the ... what's called the ventral tegmentum. That's fancy, but ventral just means bottom, and tegmentum actually means floor. So it's at the bottom of the brain, and it's the ventral part of the floor. So it's really low in the back of the brain, the ventral tegmentum, and it goes from the ventral tegmentum to what's called the ventral striatum and the prefrontal cortex.
Now, that's a lot of language, but basically what we call this is the mesocorticolimbic pathway. This is the pathway by which dopamine influences motivation, drive and craving. It involves structures that some of you may have heard of before, things like nucleus accumbens and the prefrontal cortex. This is the pathway that really gets disrupted in addictions, where in particular drugs that influence the release of dopamine, like cocaine and methamphetamine, we'll talk about those drugs today. They tap into this pathway. But if you are pursuing a partner, a boyfriend or girlfriend, if you're pursuing a degree in school, if you're pursuing a finish line in a race, you are tapping into this so-called mesocorticolimbic pathway. This is the classic reward pathway in all mammals.
The other pathway emerges from an area in the brain called the substantia nigra, so-called because the cells in that area are dark, and the substantia nigra connects to an area of the brain called the dorsal striatum. This is not surprisingly called the nigrostriatal pathway. For those of you who have never done any neuroanatomy, I'm going to teach you a little trick right now. Everything in neuroanatomy, the first part of a word tells you where the neurons are, and then the second part tells you where they are connecting to. So when I say nigrostriatal pathway, it means that the neurons are in substantia nigra and they connect to the striatum, nigrostriatal pathway. So while it's a lot of language, there is some logic there.
Okay, so we've got these two pathways. One mainly for movement. This is the substantia nigra to dorsal striatum. And we've got this other pathway, the so-called mesocorticolimbic pathway that's for reward, reinforcement and motivation. I want you to remember that there are two pathways. If you don't remember the two pathways in detail, that's fine, but please remember that there are two pathways because that turns out to be important later.
Now, the other thing to understand about dopamine is that the way that dopamine is released in the brain and body can differ, meaning it can be very local or it can be more broad. Now, most of you have probably heard of synapses. Synapses are the little spaces between neurons, and basically neurons, nerve cells, communicate with one another by making each other electrically active or by making each other less electrically active.
