Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. (Upbeat guitar music) I’m Andrew Huberman and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. For today’s podcast, we’re going to talk about the parts list of the nervous system. Now that might sound boring, but these are the bits and pieces that together make up everything about your experience of life, from what you think about to what you feel, what you imagine, and what you accomplish from the day you’re born until the day you die.

That parts list is really incredible because it has a history associated with it that really provides a window into all sorts of things like engineering, warfare, religion, and philosophy. So I’m going to share with you the parts list that makes up who you are through the lens of some of those other aspects of life and other aspects of the history of the discovery of the nervous system. By the end of this podcast, I promise you’re going to understand a lot more about how you work and how to apply that knowledge. There’s going to be a little bit of story, there’s going to be a lot of discussion about the people who made these particular discoveries, there’ll be a little bit of technical language.

There’s no way to avoid it, but at the end you’re going to have in hand what will be the equivalent of an entire semester of learning about the nervous system and how it works. Before we get started, a few important points to note: I am not a medical doctor, meaning I don’t prescribe anything. I’m a professor, so sometimes I’ll profess things – in fact, I profess a lot of things. We are going to talk about some basic functioning of the nervous system parts, and how to apply that knowledge. However, your healthcare and wellbeing is your responsibility. Therefore, when we discuss new tools or practices, please filter it through that responsibility. Make sure to talk to a healthcare professional if you want to explore any new tools or practices, and be smart in your pursuit of these new tools.

I want to emphasize that my personal goal of bringing zero cost to consumer information to the general public is separate from my role at Stanford University. I am delighted that Athletic Greens is sponsoring the podcast, as I have been using their all-in-one drink since 2012. It contains vitamins, minerals, probiotics, and prebiotics, and I like it because it is easy to take and tastes good. Furthermore, there is now a lot of data regarding the importance of gut microbiome for immune health and gut-brain access. Taking Athletic Greens helps me get all the vitamins, minerals, probiotics, and prebiotics I need.

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The nervous system includes the brain and the spinal cord, as well as the connections between the brain and spinal cord and the organs of the body. It also includes the connections between the organs back to the spinal cord and brain. This continuous loop of communication between the brain, spinal cord, and body is how we think, remember, feel, and imagine from the moment we are born until the day we die.

The nervous system is like a Mobius strip – an impossible figure that no matter which angle you look at it from, you can’t tell where it starts and where it ends. This structure allows us to deploy immune cells, releasing cells that will go and kill infection when we are in the presence of it. Most people think of this as a function of the immune system, but it is actually the nervous system that tells organs like the spleen to release killer cells to hunt down and gobble up bacterial and viral invaders. When we have a stomach ache, it is the nervous system that is causing it, and when we want to talk about experience or how to change the self in any way, we need to think about the nervous system first. It is fair to say that the nervous system governs all other biological systems of the body, and is itself influenced by those other biological systems.

The nervous system is made up of trillions of nerve cells, or neurons. Ramon y Cajal and Camillo Golgi discovered this when they figured out how to stain the nervous system in a way that revealed the individual cells. They also saw that the neurons weren’t touching each other, but were instead separated by tiny gaps called synapses. This is where chemicals from one neuron are released into the gap and received by another neuron.

The way to think about your body and your thoughts and your mind is that you are a flow of electricity. There’s nothing mystical about this; you’re a flow of electricity between these different nerve cells. Depending on which nerve cells are active, you might be lifting your arm or lowering your arm, seeing something and perceiving it as red or green. This example of perceiving red or green is particularly good because our experience of the world often makes it seem as if these things happening outside us are happening inside us. In reality, the language of the nervous system is just electricity, like a Morse code of some sort. It just depends on how they’re assembled and in what order.

The way to think about how the nervous system works is that our experiences, our memories, and everything is sort of like the keys on a piano being played in a particular order. If we play the keys on a piano in a particular order and with a particular intensity, that’s a given song. This can be analogous to a given experience. It’s not really that the key, such as A sharp or E flat, is the song; it’s just one component of the song.

The brain area called the hippocampus is involved in memory, but not in the way that memories are stored as sentences. Instead, memories are stored as patterns of electricity in neurons that when repeated, give us the sense that we are experiencing the thing again. This is what deja vu is, where we get the feeling that what we are experiencing is so familiar and like something we have experienced previously; this is because the neurons that were active in one circumstance are now becoming active in the same circumstance again.

The importance of understanding the parts of the nervous system, which includes more than just the brain, is highlighted by the discovery of neurons and synapses in the early 1900s. Since then, many important events have occurred, such as the changes in artillery in World War One, which allowed for naturally occurring lesions of the nervous system to be produced. This has given us insight into how the nervous system works and how electrical activity of neurons dictates our experience, similar to how a song may sound different when played on two different instruments.

Well, unlike previous years where a lot of the artillery would create these big sort of holes as the bullets would blow out of the brain or body, when the holes were very discrete they entered at one point and left at another point, they would take out or destroy very discrete bits of neural tissue, of the nervous system. So people were coming back from war with holes in their brain and in other parts of their nervous system that were limited to very specific locations. In addition to that, there was some advancement in the cleaning of wounds that happened, so many more people were surviving.

What this meant was that neurologists now had a collection of patients that would come back and they’d have holes in very specific locations of their brain. And they’d say things like, well, I can recognize faces but I can’t recognize who those faces belong to. I know it’s a face, but I don’t know who it belongs to. And after that person eventually died, the neurologist would figure out, ah, I’ve had 10 patients that all told me that they couldn’t recognize faces. And they all had these bullet holes that went through a particular region of the brain. And that’s how we know a lot about how particular brain regions like the hippocampus work.

In fact, some of the more amazing examples of this, where people would come back and they, for instance, would speak in complete gibberish whereas previously they could speak normally.

Even though they were speaking in complete gibberish, they could understand language perfectly. This suggests that speech and language are actually controlled by separate portions of the nervous system. There are many examples of this, such as people who cannot recognize the faces of famous people.

In the early 2000s, a paper was published in the journal “Nature” showing that in a perfectly healthy human being, there was a neuron that would become electrically active only when the person viewed the picture of Jennifer Aniston, the actress. This neuron was therefore referred to as the Jennifer Aniston cell. It is assumed that if one can recognize Jennifer Aniston’s face, they also have neurons that can recognize the faces of other famous and non-famous people.

This indicates that our brain is a map of our experience. We come into the world with a bias towards learning particular kinds of information, and our brain is ready to receive and learn this information. Ultimately, the brain is a map of experience.

Experience is the result of the nervous system’s ability to perceive and process sensory information. Sensory receptors, such as neurons in the eye, skin and ears, filter our entire experience of life. The nervous system does five or six things, of which sensation is the first. Other functions include interpreting the sensory information and making decisions based on it. Tools can be applied to make the nervous system work better and more efficiently.

There is much more happening in the world than humans are able to experience. For example, some animals, such as snakes and pit vipers, have infrared vision which allows them to sense heat emissions from other animals. Humans cannot do this without using technology such as infrared goggles. Similarly, turtles and certain species of birds have neurons in their nervous system that allow them to detect magnetic fields which helps them to migrate long distances.

Sea turtles are able to navigate the ocean using their sense of magnetism. They have neurons in their nose and head that allow them to migrate along magnetic fields, enabling them to travel thousands of miles from one location in the ocean to another. This incredible feat allows them to congregate on one particular beach at a particular time of year to mate, lay eggs, and then wander back off into the sea to die. Their young will eventually hatch and shuffle to the ocean, repeating this cycle. Humans are not magnetic sensing organisms, as we do not have receptors that sense magnetic fields. Although there is some data that suggests some humans may be able to sense magnetic fields, it is doubtful that they can do so with any degree of accuracy or robustness. This could be a topic for a future podcast.

Sensation and perception are closely related. Sensation is the process of detecting physical stimuli from the environment, while perception is our ability to take the sensations and make sense of them. We can experience the difference between perception and sensation very easily. For instance, if we pay attention to the contact of our feet with whatever surface they are in contact with, we are now perceiving what was being sensed all along. Sensation is not negotiable, however, perception is under the control of our attention.

Humans are able to do what’s called covert attention. We can place a spotlight of attention on something, for instance, something we’re reading or looking at or someone that we’re listening to. We can also place a second spotlight of attention on something we’re eating and how it tastes or our child running around in the room or my dog. We can split our attention into two locations, but of course we can also bring our attention, that is, our perception, to one particular location. We can dilate our attention kind of like making a spotlight more diffuse or we can make it more concentrated.

This is very important to understand if we’re going to think about tools to improve our nervous system, whether or not that tool is in the form of a chemical that we decide to take, maybe a supplement to increase some chemical in our brain if that’s our choice, or a brain machine device or we’re going to try and learn something better by engaging in some focus or motivated pursuit for some period of time each day. Attention is something that is absolutely under our control, in particular when we’re rested. Anyone that tells you you can’t multitask, tell them they’re wrong. And if they disagree with you, tell them to contact me.

Bottom up processing is when the nervous system passes off as much as it can to reflexive action. This is what happens when we do things like walking that we already know how to do without thinking about it. On the other hand, when we are rested and able to direct our attention in very deliberate ways, this is because of something in our nervous system which is like a two way street. This two way street is a communication between the reflexive aspects of our nervous system and the deliberate aspects of our nervous system. We will get back to this topic when we have defined rest more clearly.

The nervous system can be reflexive in its action or it can be deliberate. Reflexive action tends to be what we call bottom up, while deliberate action and perceptions, as well as deliberate thoughts, are top down. They require some effort and focus. At any moment, if something unexpected happens, such as a car screeching around the corner, you may pause and move into deliberate action. You will look around in a focused way. The point is that you can decide to focus your attention and energy on anything you want and direct your behavior in any way you desire. However, it will always feel like it requires effort and strain.

Whereas when you’re in reflexive mode, just walking and talking and eating and doing your thing, it’s going to feel very easy. This is because your nervous system is wired up to be able to do most things easily without much metabolic demand and without consuming much energy. However, the moment you try and do something very specific, you’re going to feel a sort of mental friction. It’s going to be challenging.

We’ve got sensations, perceptions, and then we’ve got things that we call feelings slash emotions. These can be complicated because almost all of us, hopefully all of us, are familiar with things like happiness and sadness or boredom or frustration. Scientists, such as neuroscientists, psychologists, and philosophers, argue like crazy about what these are and how they work. It is believed that emotions and feelings are the product of the nervous system, involving the activity of neurons which are electrically active but also release chemicals.

Neuromodulators are chemicals that have a profound influence on our emotional states. Examples of neuromodulators include dopamine, serotonin, acetylcholine, and epinephrine. These neuromodulators can be thought of as playlists that bias which neurons are likely to be active or inactive. Dopamine, for example, is often discussed as the molecule of reward or joy and it does tend to create an upbeat mood when released in appropriate amounts in the brain. This is because it makes certain neurons and neural circuits more active and others less active.

Serotonin is a molecule that when released tends to make us feel really good with what we have, our sort of internal landscape and the resources that we have. Dopamine is more a molecule of motivation toward things that are outside us and that we want to pursue. In healthy conditions, every time we accomplish something en route to a goal, a bit of dopamine is released and we feel more motivation. In extreme cases, such as mania, somebody is relentlessly in pursuit of external things like money and relationships, in a delusional state of thinking they have the resources they need when in fact they don’t.

These neuromodulators can exist in normal levels, low levels, and high levels, which gave us a window into neuroscience history – the discovery of antidepressants and so-called anti-psychotics. In the 1950s, ’60s, and ’70s, it was discovered that there are compounds that can increase or decrease serotonin and dopamine, leading to the development of most antidepressants. However, these drugs would reduce serotonin but also reduce dopamine, or increase serotonin but also increase some other neuromodulator chemical. This is because these neuromodulators have a lot of receptors, which are different than the receptors discussed earlier.

The receptors I’m talking about are like parking spots where dopamine is released. When it attaches to a receptor, it can have different effects on different organs of the body. For example, it can make the heart beat faster if the receptor is on the heart, or it can have a completely different effect on muscle. This is why some antidepressants that increase serotonin can be beneficial for people, but can also cause side effects such as blunted motivation, appetite, or libido if the doses are too high or the drug isn’t right for the individual. This is because serotonin is binding to receptors in the areas of the brain that control those other things.

We talked about sensation, perception and feelings. Neuromodulators must be considered when discussing feelings and emotions, as these are contextual. For example, in some cultures it is appropriate to show joy or sadness, whereas in others it is considered inappropriate. It is not fair to say that there is a sadness circuit or area of the brain, but certain chemicals and brain circuits tend to be active when we are in different motivated or non-motivated states. Emotions are often not under our control, as they can feel like they just happen to us, as they are somewhat reflexive.

We don’t usually set out with a deliberate thought to be happy or sad; rather, we tend to experience them in a passive and reflexive way. Thoughts are interesting because they draw on not only the present, but also past memories and future expectations. Thoughts can be reflexive, occurring all the time like pop-up windows, or we can decide to have a thought, much like writing something out on a piece of paper. We can direct our thought process, understanding that the neural circuits that underlie thoughts can be controlled in this deliberate way.

Finally, actions or behaviors are the most important aspect of our nervous system. Our behaviors are the only thing that will create a fossil record of our existence, as after death our nervous system deteriorates and our skeleton will remain. In moments of joy or sadness, it can feel so all-encompassing that we think it has meaning beyond that moment, but in reality our sensations, perceptions, thoughts, and feelings are not carried forward beyond our lifetime, except through the actions we take such as writing, speaking, and engineering. The Nobel Prize-winning neuroscientist Sherrington mapped the circuitry of nerve cells that give rise to movement and said, “Movement is the final common pathway”.

Our central nervous system, including our brain and spinal cord, is designed to impact our behavior. This is because thoughts allow us to reach into the past and anticipate the future, instead of just experiencing what is happening in the moment. This capacity for us to engage in behaviors that are based on our past experience and our desired future outcomes gives rise to an incredible ability to change our nervous system.

Movement can be either reflexive or deliberate. Reflexive movement occurs through central pattern generators, which are groups of neurons in the brain stem. Deliberate movement requires top-down processing, where the forebrain works from the top down to control the central pattern generators. This is important because it gives rise to the ability to change our nervous system.

When you do something deliberately, you pay attention and bring your perception to an analysis of three things: duration (how long something is going to take or should be done), path (what you should be doing), and outcome (if you do something for a given length of time, what’s going to happen). When you’re walking down the street, eating, or just talking reflexively, you’re not engaging this “DPO” type of deliberate function in your brain and nervous system. However, the moment you decide to learn something, resist speaking, or speak up when you would rather be quiet, you start to recruit these neuromodulators that are released from particular areas of your brain and your body. This cues your nervous system that something is different about what you’re doing and feeling.

When someone says something triggering to you, it can be difficult to prevent yourself from responding. This is an example of top down processing, where your forebrain is actively suppressing your behavior. This can cause agitation and stress, as you are suppressing a circuit. In children, this type of processing does not develop until they are 22-25 years old, which can explain why they may not be able to control their reactions in certain situations.

In young children, a robust way of expressing their emotions can be seen through rocking back and forth, as it is hard for them to sit still due to their central pattern generators. In contrast, adults are able to sit still and will usually ask or wait to be offered something they want, such as a piece of candy. However, those with damage to certain areas of the frontal lobes lack this restriction and will often blurt things out without thinking. We all know people like this.

Impulsivity is a lack of top down control, a lack of top-down processing. When people have damage to their frontal lobes, or when looking at puppies or young children, everything is a potential interaction for them and they have a hard time restricting their behavior and speech. The motor system is designed to work in a reflexive way, and then when we decide to learn something, do something, or not do something, we have to engage in top-down restriction. This is accompanied by the release of a neuromodulator called norepinephrine, which in the body is called adrenaline, and it makes us feel agitated. Additionally, the consumption of alcohol can make it harder to engage in top-down processing, as it removes inhibition by suppressing the activity of nerve cells.

Learning something new or suppressing responses can feel challenging, as the chemicals in our body are designed to make us feel agitated. This low-level tremor is what I call ‘limbic friction’, and is the result of our primitive reflexive responses in the limbic system being in a tug of war with our frontal cortex. Unless there is damage to the frontal lobe, or we’ve had too much to drink, we can work on top-down processing to shape our behavior and thinking, and to change how we are able to perform in any context. This requires feeling the agitation.

Neuroplasticity is the process by which neurons can change their connections and the way they work. This change can occur naturally, or it can be induced by brain damage. Most of the neuroplasticity that people want is self-directed plasticity. It is often the result of agitation and strain, and it is typically positive or adaptive. The brain is especially plastic from birth until about age 25. With this plasticity, it is possible to go from challenging and deliberate tasks to more reflexive ones.

Kids are learning all sorts of things passively, without having to work too hard or focus too hard (although focus helps). However, if you are an adult and you want to change your neural circuitry at the level of emotions, behavior, thoughts, or anything really, you need to ask two important questions. The first question is: what particular aspect of my nervous system am I trying to change? The second question is: how am I going to go about that? It turns out that the answer to the second question is governed by how awake or how sleepy we are. Let’s talk about that next.

Neuroplasticity is the ability for connections in the brain and body to change in response to experience. What is so incredible about the human nervous system is that we can direct our own neural changes. We can decide that we want to change our brain and our nervous system can change itself. This is not the same for other organs of the body, as they can only change in a limited way without being able to think and decide. For example, the gut cannot decide to rearrange its connections to be able to digest spicy foods better. However, the brain can decide to learn a language, be less emotionally reactive or more emotionally engaged, and undergo a series of steps to make those changes reflexive. It was once thought that neuroplasticity was only possible in young animals and humans, but it is now known that it can occur at any age. A young brain is especially plastic.

Children have the ability to learn three languages without an accent, while adults find this much more challenging. It takes a lot more effort and duration for adults to make the plastic changes needed to achieve this. However, research has shown that the adult brain can change in response to experience. Nobel prizes were awarded for the discovery that the young brain can change dramatically. For example, those born blind from birth use the area of the brain normally used for visualizing objects for braille reading. Brain imaging studies have demonstrated that the area of the brain that would normally light up for vision lights up for braille reading when these people read braille. If someone is made blind in adulthood, it is unlikely that their visual brain will be taken over by the areas of the brain responsible for touch. However, some evidence suggests that areas of the brain involved in hearing and touch can migrate into the area. There is now a lot of interest in trying to figure out how to induce more plasticity in adulthood, with more positive outcomes.

In order to understand the process of neuroplasticity, we must understand the role of neuromodulators. Dopamine, serotonin, and acetylcholine are what open up plasticity and allow for the mapping of information in the brain. This can have a positive side, as it is easy to get neuroplasticity as an adult through challenging experiences. However, this is due to the release of two sets of neuromodulators in the brain: epinephrine, which makes us alert and agitated, and acetylcholine, which creates a focused perceptual spotlight. This allows us to experience and feel something more easily.

Earlier, we were discussing perception and how it is similar to a spotlight. Acetylcholine makes this spotlight particularly bright and focused on one region of our experience. It does this by activating certain neurons in the brain and body more than the others. Acetylcholine can be thought of as a highlighter marker, which neuroplasticity then uses to identify which neurons were active during the alerting phase. Epinephrine creates the alertness, which is created by a subset of neurons in the brain stem. Acetylcholine, coming from an area of the forebrain, marks the neurons and synapses that are particularly active during this heightened level of alertness. This makes these cells, neurons, and synapses more likely to be active in the future without us having to think about it. In bad circumstances, this all happens without us having to do much.

We want something to happen, however, we know that the process of getting neuroplasticity – so that we have more focus, more motivation – absolutely requires the release of epinephrine. We have to have alertness in order to have focus and we have to have focus in order to direct those plastic changes to particular parts of our nervous system. This has immense implications in thinking about the various tools, whether or not those are chemical tools or machine tools or just self-induced regimens of how long or how intensely we’re going to focus in order to get neuroplasticity.

The dirty secret of neuroplasticity is that no neuroplasticity occurs during the thing we’re trying to learn. All the neuroplasticity, the strengthening of the synapses, the addition of new nerve cells or at least connections between nerve cells, all of that occurs at a very different phase of life – when we are in sleep and non-sleep deep rest.

This is important to consider when thinking about New Year’s resolutions. What happens in March or April or May when motivation is low? Neuroplasticity is the Holy Grail of human experience and understanding how it works is key to achieving our goals.

Well, that all depends on how much attention and focus one can continually bring to whatever it is they’re trying to learn, so much so that agitation and a feeling of strain are actually required for this process of neuro-plasticity to get triggered. But the actual rewiring occurs during periods of sleep and non-sleep deep rest. There’s a study published last year that’s particularly relevant here, which was not done by my laboratory, that showed that 20 minutes of deep rest (not deep sleep) immediately after intense focus, can actually accelerate neuroplasticity.

Another incredible study showed that if people are learning a particular skill (such as a language or motor skill) and they hear a tone playing in the background periodically, learning is much faster in deep sleep. The tone acts as a Pavlovian cue to the sleeping brain, reminding it that something important happened in the waking phase. This results in higher rates of retention and learning. I will be discussing how to apply this knowledge in this and future podcast episodes.

Sleep and focus are key elements of attentional state. When we are asleep, we are unable to analyze duration, path, and outcome. During periods of deep rest, our attention drifts and this is important for the consolidation of the things we have learned, allowing them to become reflexive and easy. Modern clinicians are also thinking of ways to prevent bad circumstances from becoming permanently routed into our nervous system, and this can be done by interfering with the brain states that come after the bad thing that happened.

We want to make sure that we pay attention to the fact that for many of you, you’re thinking about neuroplasticity not just in changing your nervous system to add something new, but to also get rid of things that you don’t like. We want to reduce the emotional load of bad experiences or a bad relationship to something or someone, or an event. We can also learn to fear certain things less, or even eliminate a phobia or erase a trauma, although the memories themselves don’t get erased.

We need to understand how the autonomic nervous system works. It is a two phase process, which governs the transition between alert and focused states, and deep rest and deep sleep states. It is also known as the sympathetic and parasympathetic nervous systems, which can be a little bit misleading. It is immensely important to understand how this autonomic nervous system works.

The autonomic nervous system is associated with two states: alertness and calmness. Sympathetic and parasympathetic are sometimes used to refer to these states, but people often get confused. The autonomic nervous system works like a seesaw, with us becoming more alert in the morning and more relaxed and sleepy in the evening. Eventually, we go from alert to deeply calm when we go to sleep.

We go from an ability to engage in these very focused duration, path, outcome types of analyses to states in sleep that are completely divorced from duration, path, and outcome in which everything is completely random and untethered in terms of our sensations, perceptions, and feelings. Every 24 hours, we have a phase of our day that is optimal for thinking, focusing, learning, and doing all sorts of things. We have energy as well. At another phase of our day, we’re tired and have no ability to focus or engage in duration, path, outcome types of analyses. Both phases are important for shaping our nervous system in the ways that we want. If we want to engage neuroplasticity and get the most out of our nervous system, we each have to master the transition between wakefulness and sleep and the transition between sleep and wakefulness.

Now so much has been made of the importance of sleep. It is critically important for wound healing, learning, consolidating learning, and all aspects of our immune system. It is the one period of time in which we’re not doing these duration, path, and outcome types of analyses.

Much less has been made of how to get better at sleeping, how to get better at the process that involves falling asleep, staying asleep, and accessing the states of mind and body that involve total paralysis. Most people don’t know this, but you’re actually paralyzed during much of your sleep so that you can’t act out your dreams, presumably. But also, where your brain is in a total idle state, it’s just left to kind of free run.

And there are certain things that we can all do in order to master that transition, in order to get better at sleeping. It involves much more than just how much we sleep; we’re all being told, of course, that we need to sleep more, but there’s also the issue of sleep quality, accessing those deep states of non-DPO thinking. Accessing the right timing of sleep has not been discussed publicly, as far as I’m aware.

I think we all can appreciate that sleeping for half an hour throughout the day so that you get a total of eight hours of sleep every 24-hour cycle is probably very different and not optimal compared to a solid block of eight hours of sleep. Although there are people that have tried this, I think it’s been written about in various books.

It is critically important to all aspects of our health, including our longevity, to get better at sleeping.

Ultradian rhythms are shorter than that. They’re anywhere from 90 minutes to four hours.

Not many people can stick to the Uberman schedule, which is not to be confused with the Huberman schedule. My own schedule does not resemble this. I would never attempt such a sleeping regime. We have not explored, as a culture, the rhythms that occur in our waking states. Much focus has been put on the value of sleep and its importance, which is great. However, most people are not paying attention to what is happening in their waking states when their brain is optimized for focus, learning, changing, and reflexive thinking.

Scientific data points to the existence of ultradian rhythms, which are shorter than circadian rhythms, ranging from 90 minutes to four hours. Understanding these rhythms can help us to optimize our waking states and our learning and focus.

Ultradian rhythms occur throughout the day and are shorter than other rhythms. The most important one for this discussion is the 90 minute rhythm which affects our ability to attend and focus. It is also reflected in the way we sleep, which is broken up into 90 minute segments. Early in the night, we experience more phase one and two lighter sleep, before going into deeper phase three and four sleep. This cycle of stage one, two, three, four then repeats all night. Many people are aware of this, but it is also true that these ultradian rhythms continue when we wake up in the morning.

We are optimized for focus and attention within 90 minute cycles. At the beginning of one of these cycles, it is well-known that our brain and neural circuits are not optimally tuned. However, as we drop deeper into the cycle, our ability to focus, engage in a DPO process, direct neuroplasticity, and learn is much greater. We eventually pop out of the cycle at the end of the 90 minute cycle. These cycles occur in sleep and in wakefulness, and are governed by the autonomic nervous system. To master and control our nervous system, we need to understand that our entire existence occurs in these 90 minute cycles. It would be counterproductive to try and learn information while in deep sleep, but it is perfectly good to engage in a focused bout of learning each day for at least one 90 minute cycle.

When are you most creative?

The expectation should be that the early phase of that cycle is going to be challenging. It’s going to hurt and it’s not going to feel natural or like flow. However, you can learn and the circuits of your brain involved in focus and motivation can learn to drop into a mode of more focus, getting more neuroplasticity in other words, by engaging these ultradian cycles at the appropriate times of day.

For instance, some people are very good learners early in the day and not so good in the afternoon. You can start to explore this process even without any information about the underlying neurochemicals by simply paying attention, not just to when you go to sleep and when you wake up each morning, how deep or how shallow your sleep felt to you subjectively, but also throughout the day when your brain tends to be most anxious. That has a correlate related to perception which we will talk about. You can ask yourself when are you most focused, when are you most creative?

By understanding the different aspects of your perception, sensation, feeling, thought, and actions, you can develop a window into what is required to shift your focus or engage in creative type thinking at different times of the day. This all starts with mastering the autonomic nervous system, which is a transition between wakefulness and sleep, but also includes various 90 minute ultradian cycles that govern our life 24 hours a day. We can take control of the autonomic nervous system to access neuroplasticity, sleep, and creativity. This is based on studies published in the last 100 years, mainly within the last 10 years, and some that are very new. These studies point to the use of specific tools to get the most out of our nervous system.

Today we covered a lot of information about neurons, synapses, neuroplasticity, and the autonomic nervous system. We will revisit these topics going forward, so don’t worry if you didn’t fully understand everything in one pass. I wanted to provide a common base of information for us to use as we move ahead.

This information can be valuable to you in understanding what works well for you, what is challenging, and what has been easy. In the “Huberman Lab” podcast, we will dive deep into individual topics for an entire month. For January, we will explore sleep and non-sleep deep rest and how they impact learning, resetting our emotional capacity, and dealing with life circumstances when we are sleep deprived.

We’re going to be discussing how we’re more emotionally labile and why and how that is. Most importantly, we’re going to talk about how to get better at sleeping and how to access better sleep even when your sleep timing or duration is compromised. We’ll also be discussing the data that support a state called non-sleep deep rest, which is neither asleep nor awake, but can help to recover neuromodulators and processes involved in sensation, perception, feeling, thought, and action. We’ll be discussing neuroscience and how this phase of life, where one is not conscious, can actually reset and renew oneself to perform better and feel better in the waking state. Lastly, if you want to support the podcast, please click the like button, subscribe on YouTube, leave us a comment with feedback, and leave a review and comments on Apple.

Thanks for joining us for this episode! (upbeat guitar music) We hope you enjoyed it. Please don’t forget to check out our sponsors and thank you for your support. We’ll see you on the next episode next week.