Speaker A
As we get into adulthood, most of our neural maps in the brain, certainly our sensory maps and our cortex, our motor maps that allow us to move in particular ways, those have been established. You can still change them, but they've
Huberman explains how adult neuroplasticity requires alertness and focus, with acetylcholine from nucleus basalis and vagus nerve stimulation via exercise opening a plasticity window.
Key Takeaways
- Adult neuroplasticity requires both alertness and focus, not passive exposure.
- Exercise, especially high-intensity, can open a plasticity window by engaging the vagus nerve and acetylcholine pathways.
- Incremental, repeated learning sessions followed by good sleep maximize lasting neural change.
- Nicotine enhances acetylcholine but is habit-forming and harmful, so its risks outweigh its cognitive benefits.
What the video covers
- Adult neural maps are largely established by early adulthood but can still be modified through neuroplasticity.
- Unlike childhood learning through passive exposure, adult plasticity requires both alertness and focus.
- Incremental learning, repeated small bouts over time, can yield plasticity comparable to childhood levels, just more slowly.
- Acetylcholine released from the nucleus basalis acts as a permissive gate that makes neuroplasticity much more likely for a period of time.
- Animal and human studies show that stimulating nucleus basalis acetylcholine release leads to rapid cortical remapping according to sensory experience.
- Pharmacological options such as alpha-GPC, huperzine, and nicotine can increase acetylcholine, but nicotine carries serious health and addiction risks.
- Vagus nerve stimulation increases alertness and can enhance acetylcholine release via a pathway from the NTS to nucleus basalis, aiding stroke recovery.
- High-intensity exercise activates the vagus nerve and locus coeruleus norepinephrine release, boosting alertness and triggering a plasticity window for several hours.
- Alertness (via norepinephrine) and focus (via acetylcholine) together are the triggers for adult neuroplasticity.
- Plasticity consolidates during sleep, especially deep sleep and REM, so good sleep is essential after learning.
Chapters
- 00:00Neural Maps and Adult Plasticity
- 00:53Alertness and Focus as Requirements
- 01:43Acetylcholine and Nucleus Basalis
- 02:42Pharmacological Enhancers and Nicotine Risks
- 04:25Vagus Nerve and Brain Alertness Pathways
- 06:24Exercise, Norepinephrine, and Plasticity Windows
- 08:01Sleep and Consolidation of Plasticity
- 08:57Focus Training and Organizing Learning Bouts
- 10:45Exercise as a Trigger for Lifelong Plasticity
Full Transcript — Download SRT & Markdown
Speaker A
mostly been established throughout childhood and into our early 20s. And if we want to modify those circuits with neuroplasticity, there are a couple of key requirements. One, you need to be alert. You can't get neuroplasticity.
Speaker A
That is, you can't trigger neuroplasticity unless you're alert. You also have to be focused. This is critical and differentiates adult plasticity in a major way from plasticity when we're young where we can learn by passive exposure. Okay? When
Speaker A
we're young, we can learn by passive exposure or even better by focused exposure. But when we are adults, we need alertness and we need focus. Just passively being exposed to, you know, music or to a motor pattern is not going
Speaker A
to allow us to change our nervous system. That's been shown over and over again. Fortunately, what also has been shown over and over again is that if we are alert and we're focused and we are determined, especially if we undertake
Speaker A
what's called incremental learning, where we go after small bits of neuroplasticity repeatedly over time, we can get as much neuroplasticity as one observes in childhood. It just takes longer and you have to do it so-called incrementally.
Speaker A
There's a lot to say about that, but for sake of today's discussion about the vagus nerve, I just want to tell you that there's a particular pathway in the brain that involves the molecule acetylcholine. Acetylcholine is used to
Speaker A
contract the muscles. It's released from motor neurons in the spinal cord onto muscles to contract the muscles. It's also used in the brain and elsewhere in the nervous system and it does a lot of different things. It's actually involved
Speaker A
in generating the rhythms of the heart. But acetylcholine released from a particular nucleus in the brain called nucleus basalis. The acetylcholine released from nucleus basalis is what we call permissive for plasticity. In other words, if you have acetylcholine
Speaker A
released from nucleus basalis into the brain, plasticity is much more likely to occur. And in fact acetylcholine released from nucleus basalis is sort of like a gate whereby if you release acetylcholine the opportunity for neuroplasticity and learning is
Speaker A
available for some period of time. So the question therefore becomes how do you get acetylcholine released from nucleus basalis. There are these incredible experiments that have been done by Mike Merzik and colleagues showing that if you stimulate nucleusalis to release acetylcholine and
Speaker A
you expose an animal or a human to a particular sensory stimulus, the brain remaps very fast according to that experience. Just enormous amounts of plasticity that you wouldn't observe otherwise. There are also fortunately experiments showing that if you
Speaker A
pharmacologically increase acetylcholine that you can enhance the opportunity for neuroplasticity. You still need to do the learning. You still need to attempt to learn something. You still have to make it incremental, but the amount of plasticity is significantly increased
Speaker A
when there's acetyloline released from nucleus basalis. So in the absence of deep brain stimulation using an electrode, which most of you fortunately will not experience because it requires drilling down through the skull and placing an electrode in basalis and
Speaker A
assuming that you're not taking anything to increase acetyloline transmission to learn, although there are ways to do that. I've talked about that before and I'll talk about that again in a future podcast. Some of those ways include supplementing with things like alphagpc
Speaker A
which is a precursor to acetylcholine. There are some other precursors to acetyloline or things that stimulate the release of acetylcholine such as hooperine and things like that that will open the opportunity for enhanced plasticity for a few hours. And there is
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good old nicotine. I know the word nicotine brings to mind things like lung cancer because for many many years, many many people and still now smoked nicotine in the form of cigarettes or vaping. Both of which I think are
Speaker A
absolutely terrible as is dipping and snuffing because yes, they increase levels of nicotinic acetylcholine receptor activation, which is just fancy nerd speak for acetyloline transmission in the brain is enhanced by nicotine.
Speaker A
But those delivery mechanisms also of course can give you cancer in the case of smoking, dipping, or snuffing. And vaping, despite what you hear out there, is absolutely terrible for your health.
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I don't care what anybody says, the evidence is starting to really pile up that vaping is bad for you. Now, is oral form nicotine bad for you in the form of gum or in the form of a pouch, etc.? I
Speaker A
just want to say a couple of things. One, it's extremely habit forming. Two, it increases blood pressure. and it's a vasoc constrictor. These drawbacks about nicotine are real and are critical to consider if you're going to use nicotine
Speaker A
as a focusing agent or a so-called neutropic. I don't really like that word, but if you're using nicotine as a way to enhance cognition and enhance neuroplasticity, you should know what the potential drawbacks are. Most notably, the habit forming and addicting
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properties, which are very robust. Now with that said, there are ways to non-farmacologically stimulate the nucleus basalis acetyloline pathway to enhance the window for plasticity and the way to do that is you guessed it through the vagus nerve. Studies in
Speaker A
healthy humans and humans who have had for instance stroke as well as animal studies have shown that if you stimulate the vagus nerve electrically you increase the level of alertness in the brain. And part of the mechanism by
Speaker A
which you do that is the one I told you about a few minutes ago. the adrenals, vagus, locus ceruius, but also there's a separate pathway from the NTS to nucleus basalis that stimulates the release of acetylcholine from nucleus basalis and
Speaker A
opens up the opportunity for neuroplasticity. This I should mention is not a small effect. It is a rapid effect and it's one that has allowed stroke patients for instance to improve their motor capabilities very quickly as compared to
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when the Vegas nerve is not stimulated or when acetyloline transmission is not enhanced pharmacologically. And fortunately now there are studies starting to accumulate in animal models and some in humans. We need more. But there are some showing that if you
Speaker A
enhance alertness by way of activating the vagus nerve through the mechanism that I told you before, which is good old-fashioned high-intensity exercise, that in the several hours following that exercise, there is an enhanced opportunity for neuroplasticity. Now, that enhanced opportunity for
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neuroplasticity comes by way of two different pathways. You already heard about the first one, which is the locus ceruius release of norepinephrine.
Speaker A
That's going to increase alertness, which is a prerequisite for focus. And it appears to be the case that the release of acetylcholine from nucleus basalis that's also triggered by this high-intensity exercise is what allows for that alertness to be converted into
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focus. And those two things together, alertness and focus, are the triggers for adult neuroplasticity. If you think about this, this is really exciting. For 25 years or more, we've known that plasticity is possible in the adult human. We knew you needed alertness and
Speaker A
you needed focus. We also, by the way, know that you need to get great sleep that night and in subsequent nights in order to actually allow the plasticity to occur. Plasticity is a process. It's not just triggered when you go about
Speaker A
trying to learn something. It actually takes place in sleep as well as sleep-like states like non-sleep, deep rest, and meditation. But especially in deep sleep and rapid eye movement sleep.
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This is why you can attempt to learn something cognitively or behaviorally over and over and over. you can't get those scales on the piano right. You can't get the, you know, the information dialed in from your class, a language
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class or from engineering or you're trying to figure out what this picture should be in your mind that you're going to paint, etc. You work at it, you work at it, you work at it, you sleep, you sleep, and then one day you wake up and
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suddenly you have the skill. It's because the actual rewiring of those circuits that we call neuroplasticity occurs during sleep, but it's triggered in those moments of incremental learning and really struggling. And keep in mind the struggle to learn something. That
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friction is part of the neuroplasticity process. And it's oh so clear now that alertness and focus are the prerequisites for plasticity. That alertness is coming in large part by way of the release of norepinephrine from locuser. That the focus is being
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augmented and perhaps even originating entirely from the release of acetylcholine and nucleus basalis. that acts as sort of a spotlight on a particular set of things that are happening while we're trying to learn and then that triggers the plasticity
Speaker A
process which takes place during sleep. So that beautiful picture of self-directed adaptive plasticity in adulthood is allowed to happen because the vagus nerve in part is triggering NTS to say hey locus ceruleius nucleus basalis wake up release norepinephrine
Speaker A
release acetylcholine now's the time to learn. So, what this means is if you're struggling to learn, if you want to continue to have robust neuroplasticity, if you happen to have some damage to motor pathways or you're having trouble
Speaker A
with focusing and brain fog, keep in mind focus itself is served by a circuit that is subject to plasticity, you can actually get better at focusing by working on focus just the same way you would on any skill. And so if you're
Speaker A
struggling with focus, I highly recommend finding a threshold of exercise that stimulates brain alertness that triggers these pathways that are now starting to be clear that they occur from the literature in animals and humans. And yes, you might augment this
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with something like caffeine, which will further increase levels of norepinephrine. You might even use lowdose nicotine. I'm not necessarily recommending that, certainly not for young people. And you do need to be aware of the habit forming aka addictive
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properties of nicotine. You definitely don't want to consume it in any form that's going to cause you to increase your risk of cancer or popcorn lung from vaping. You could use pharmarmacology.
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You could use alpha GPC. You could use herine in combination with exercise. However, I strongly strongly recommend that anyone who's interested in lifelong learning, think about organizing your bouts of learning, especially cognitive learning, to come in the two to three
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hours, maybe even four hours, but certainly in the 1 to two hours after you do some sort of exercise that doesn't leave you exhausted, but leaves you with elevated levels of energy in your body. So, you don't want to take
Speaker A
this physical exercise that I'm talking about to exhaustion because that's going to leave you depleted. that's going to cause a you know uptick in parasympathetic activity. Any of you that have done a hard leg workout and then you know 2 three hours later you're
Speaker A
just like it's very clear brain oxygen levels are down parasympathetic activity is up you are tired because you exhausted all that energy and exercise.
Speaker A
But if you can use exercise as a trigger to release adrenaline and stimulate these pathways within the brain that arrive via the signaling from the vagus, you do indeed open up the opportunity for enhanced neuroplasticity at any age.
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Topics:neuroplasticityvagus nerveacetylcholinenucleus basalisadult learningalertnessfocushigh-intensity exercisesleepHuberman Lab
