Lex Fridman PodcastAndrew Huberman: Neuroscience of Optimal Performance | Lex Fridman Podcast #139
EVERY SPOKEN WORD
150 min read · 30,261 words- 0:00 – 2:29
Introduction
- LFLex Fridman
The following is a conversation with Andrew Huberman, a neuroscientist at Stanford working to understand how the brain works, how it can change through experience, and how to repair brain circuits damaged by injury or disease. He has a great Instagram account @hubermanlab where he teaches the world about the brain and the human mind. Also, he's a friend and an inspiration in that he shows that you can be humble, giving, and still succeed in the science world. Quick mention of each sponsor followed by some thoughts related to the episode. Eight Sleep, a mattress that cools itself and gives me yet another reason to enjoy sleep. SEMrush, the most advanced SEO optimization tool I've ever come across. And Cash App, the app I use to send money to friends. Please check out these sponsors in the description to get a discount and to support this podcast. As a side note, let me say that I heard from a lot of people about the previous conversation I had with Yaron Brook about objectivism. Some people loved it, some people hated it. I misspoke in some parts, was more critical on occasion than I'm meant to be, didn't push on certain points that I should have, was under-educated or completely unaware about some major things that happened in the past or major ideas out there. I bring all that up to say that if we are to have difficult conversations, we have to give each other space to make mistakes, to learn, to grow. Taking one or two statements from our three-hour podcast and suggesting that they encapsulate who I am, I was, or ever will be is a standard that we can't hold each other to. I don't think anyone could live up to that kind of standard, at least I know I can't. The conversation with Yaron is mild relative to some conversations that I will likely have in the coming year. Please continue to challenge me, but please try to do so with love and with patience. I promise to work my ass off to improve. Whether I'm successful at that or not, we shall see. If you enjoy this thing, subscribe on YouTube, review it with five stars on Apple Podcasts, follow on Spotify, support on Patreon, or connect with me on Twitter @lexfridman. And now here's my conversation with Andrew Huberman.
- 2:29 – 10:41
Fear
- LFLex Fridman
You've mentioned that in your lab at Stanford, you (laughs) induce stress by putting people into, uh, virtual reality and having them go through one of a set of experiences, I think you mentioned this on Rogan or with Whitney, that scare them.
- AHAndrew Huberman
Mm-hmm.
- LFLex Fridman
So just, uh, on a practical, psychological level and maybe on a philosophical level, wha- what are people afraid of? What are the fears? What are these fear experiences (laughs) that you find to be effective?
- AHAndrew Huberman
Yeah, so it depends on the person obviously, um, and we should probably define fear, right? 'Cause you can...
- LFLex Fridman
(laughs) Yeah.
- AHAndrew Huberman
Uh, w- without going too far down the rabbit hole of...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
... of defining these things. Um, you know, you can't really have fear without stress, but you could have stress without fear. And you can't really have trauma without fear and stress, but you could have fear and stress without trauma. So, you know, we can start playing the word game, and that actually is one of the motivations for even having a laboratory that studies these things is that we really need better physiological, neuroscientific, and operational definitions of what these things are.
- LFLex Fridman
Okay.
- AHAndrew Huberman
I mean, the, the field of understanding, um, emotions and states, which is mainly what I'm interested in, is very complicated, but we can, um, we can do away with a lot of complicated debate and say in our laboratory what we're looking for to assign it a value of fear is a big inflection in autonomic arousal, so increases in heart rate, increases in breathing, u- um, perspiration, pupil dilation, all the hallmark signature features of the stress response.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Uh, and in some cases, we have the benefit of getting neurosurgery patients where we've got electrodes in their amygdala, in their insula, in their orbital frontal cortex, um, down beneath the skull, so these are chronically implanted electrodes, we're getting multiunit signals and we can start seeing some central features of, uh, meaning within the brain. And what's interesting is that as trivial as it might seem in listening to it, almost everybody responds to heights and falling from a high virtual place with a very strong stress, if not fear response. And that's because the visual vestibular apparatus eye, right, the, the optic flow and how it links to the, you know, balanced semicircular canals of the inner ears, all this technical stuff, but really all of that pools all your physiology. The, the feeling that your stomach is dropping, the feeling that you're... Suddenly you're sweating even though you're not afraid of falling off this virtual platform, but you feel as if you're following- falling, excuse me, because of the optic flow. That one is universal. So we've got a dive with great white sharks experience where you actually exit the cage, we went out and-
- LFLex Fridman
(laughs)
- AHAndrew Huberman
... did this in the real world and brought back 360 video that's built out pretty...
- LFLex Fridman
Oh, so this is actual 360 video? That's awesome.
- AHAndrew Huberman
360 video, and this was important to us, right? So when we decided to set up this platform, a lot of the motivation was that a lot of the studies of, of these things in laboratories, I don't want to call them lame because I want to be respectful of the, the people that did this stuff before, but they study fear by, you know, showing subjects a picture of a bloody arm...
- LFLex Fridman
Right.
- AHAndrew Huberman
... or a snake, or something like that, or... And it just, unless you have a snake phobia, it just wasn't creating a real enough experience. So we need to do something where people aren't gonna get injured, but where we can tap into the physiology and that thing of presence of people momentarily, not the whole time, but momentarily-...forgetting they're in a laboratory.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
And so heights will always do it. And I, if people want to challenge me on this, I like to point to that movie Free Solo, which was wild because, you know, it's an incredible movie, but I think a lot of its popularity can be explained by a puzzle, which is, you knew he was gonna live when you walked in the theater...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
...or you watched it on, at home. You knew before that he, he survived, and yet it was still scary, that people were somehow able to put themselves into that experience or into Alex's experience enough that they, they were concerned or worried or afraid at some level. So heights always does it. If we get people who have generalized anxiety, these are people who wa- wake up and move through life at a generally higher state of autonomic arousal and anxiety, then we can tip them a little bit more easily with things that don't necessarily get everyone afraid, things like, um, claustrophobia, public speaking. That's gonna vary from person to person. Um, and then if you're afraid of sharks, like my sister, for instance, is afraid of sharks, she won't even come to my laboratory, because there sh- there's a thing about sharks in it. That's how terrified some people are of these specific stimuli. But heights gets them every time.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And...
- LFLex Fridman
I'm terrified of heights.
- AHAndrew Huberman
It, it's... You know, when we have you step off a platform, virtual platform, and it's a flat floor in my lab, but we... You're up there.
- LFLex Fridman
Well, you actually allow them the possibility in the virtual world to actually take the leap of faith?
- AHAndrew Huberman
Yeah, maybe I should describe a little bit of the experiment. So, um, without giving away too much, in case someone wants to be a subject in one of these, uh, experiments, we have them playing a cognitive game. It's a simple lights out kind of game where you're, you know, pointing a cursor and turning out lights on a grid. But it gets increasingly complex and it speeds up on them, and, um, you know, there's a failure point for everybody where they just can't make the motor commands fast enough. And then we surprise people, essentially, by placing them virtually. All of a sudden, they're sus- they're on a narrow platform between two buildings.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And then we encourage them or we cue them with a, with a... By talking to them through a microphone to continue across that platform to continue the game. And, you know, some people, they, they just won't d- they actually will hold... Get down on the ground and hold onto a virtual beam that doesn't even exist on a flat floor. And so what this really tells us is the power of the brain to enter these virtual states as if they were real. And we really think that anchoring the visual and the vestibular, the balance components of the nervous system, are what bring people into that presence so quickly. There's also the potential, and we haven't done this yet, to bring in 360 sound. So the reason we did 360 video is that when we started all this back in 2016, a lot of VR was pretty lame, frankly. It was CGI. It just wasn't real enough. But with 360 video, we knew that we could get people into this presence where they think they're in a real experience more quickly. And our friend, Michael Moller, who I was introduced to because of the project, I reached out to some friends. Michael Moller's a very famous, um, portrait photographer in Hollywood, but he dives with great white sharks and he leaves the cage.
- 10:41 – 14:25
Virtual reality
- AHAndrew Huberman
.
- LFLex Fridman
Well, from a psychology and from a neuroscience perspective, this whole construction that you've developed is fascinating. We did this a little bit with autonomous vehicles, so to try to understand the decision-making process of a pedestrian when they cross the road, and trying to create an experience of a car, you know, that could run you over, so there's the danger of there. I was so surprised how real that whole world was, and the graphics that we built wasn't ultra-realistic or anything, but I was still afraid of being hit by a car. E- everybody we tested were really afraid of being hit by that car.
- AHAndrew Huberman
Even though it was all a simulation?
- LFLex Fridman
It was all a simulation. It was, uh, it was kind of boxy, actually.
- AHAndrew Huberman
Mm-hmm.
- LFLex Fridman
I mean, it wasn't like ultra-realistic simulation. And it's fascinating.
- AHAndrew Huberman
I mean, l- looms and heights. So, any kind of depth, we're just programmed to, um, to not necessarily recoil, but to be cautious about that edge and that depth. And then looms, things coming at us that are getting larger. There are looming sensing neurons even in the retina...
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
...at the very, very early stage of visual processing. And, um, incidentally, uh, the way...... Mueller and, you know, folks learned how to not get eaten by great white sharks when you're swimming outside the cage is as they start c- lumbering in, you swim toward them. And they get very confused when you loom on them.
- LFLex Fridman
Okay.
- AHAndrew Huberman
Because clearly you're smaller, clearly they could eat you if they wanted to, but there's something about forward movement toward, uh, any creature that that creature questions whether or not it would be a good idea to generate forward movement toward you. And so that's actually the survival tool of these cage exit white shark divers.
- LFLex Fridman
Are you playing around with... Like, one of the critical things for the autonomous vehicle research is you couldn't do 360 video because the, there's a game theoretic, there's an interactive element that's really necessary. So maybe people realize this, maybe they don't, but 360 video, you obviously... Well, it's actually not that obvious to people, but you can't change the reality that you're watching. (laughs)
- AHAndrew Huberman
That's right.
- LFLex Fridman
So, uh, but you find that that's... Like, is there something fundamental about fear and stress that the interactive element is essential for? Or do you find you can, you can arouse people with just the video?
- AHAndrew Huberman
Great question. Um, it works best to use mixed reality. So we have a snake stimulus. Uh, I personally don't like snakes at all. I don't mind spiders, we also have a spider stimulus, but, like, snakes, I just don't like them.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
There's something about the, the slithering and the... It just, it creates a visceral response for me. Um, some people not so much and they have lower levels of stress and fear in there. But one way that we can get them to feel more of that is to use mixed reality where we have a, an actual physical bat and they have to stomp out the snake as opposed to just m- um, walk to a little safe corner.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Which then makes the snake disappear. That tends to be not as stressful as if they have a physical weapon. And so you got people in there, you know, banging on the floor...
- LFLex Fridman
(laughs)
- AHAndrew Huberman
... against this thing, and there's something about engaging that makes it more of a th- more of a threat. Now I should also mention...
- LFLex Fridman
That's true.
- AHAndrew Huberman
... we, we always get the subjective report from the subject of what they experienced because I, we never wanna project our own ideas about what they were feeling, but that's the beauty of working with humans is you can ask them how they feel.
- LFLex Fridman
Exactly.
- AHAndrew Huberman
And humans aren't great at explaining how they feel, um, but it's a lot easier to understand what they're saying than a mouse or a macaque monkey is saying. (laughs) Um, so it's the best we can do is language plus these physiological and neurophysiological
- 14:25 – 16:13
Claustrophobia
- AHAndrew Huberman
signals.
- LFLex Fridman
Is there something you've learned about yourself, about your deepest fears? Like, you said snakes. Is there something that... Like, if I were to torture you, I'm, so I'm Russian, so, you know, I always kinda think how can I murder this people then, this person that entered the room, but also how, how can I torture you to get some information out of you? What, w- what, what would I go with?
- AHAndrew Huberman
Hmm. It's interesting you should say that. I never considered myself claustrophobic.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
But, um, 'cause I don't mind small environments pr- provided they're well-ventilated, but I, uh, before COVID, I started going to this Russian banya.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Um, you know...
- LFLex Fridman
(laughs)
- AHAndrew Huberman
... in the ******* area, and I had never been to a banya.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
So, you know, the whole experience of really, really hot sauna.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And, uh, what do they call it? The plotza? They're hitting you with the leaves and...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And it gets really hot and humid in there, and there were a couple times where I thought, "Okay, this thing is below ground, it's in a city where there are a lot of earthquakes, like, if this place crumbled and we were stuck in here." And I'd start getting a little panicky.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And I realize and I'm like, "I don't like small, confined spaces with poor ventilation." So I realize, I think I have some claustrophobia, and I wasn't aware of that before. So I've put myself into our own claustrophobia stimulus which involves getting into an elevator...
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... um, and, with a bunch of people, virtual people, and the elevator gets stalled. And at first you're fine, you feel fine, but then as we start modulating the environment and we actually can control levels of oxygen in the environment if we want to, um, it is really uncomfortable for me and I never would have thought... You know, I fly, I'm comfortable in planes, I... But it is really uncomfortable and so I think I've un-
- LFLex Fridman
Claustrophobia.
- AHAndrew Huberman
... unhatched a bit of, uh, claustrophobia.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Yeah.
- 16:13 – 17:48
Skydiving
- AHAndrew Huberman
- LFLex Fridman
Yeah, for me as well probably. That one, that one's pretty bad. The heights I try to overcome, so I went skydiving to try to overcome the fear of heights, but that didn't help.
- AHAndrew Huberman
Did you jump out?
- LFLex Fridman
Yeah, I ju-
- AHAndrew Huberman
All right.
- LFLex Fridman
Yeah, I ju- jumped out, but it was, it was a, it was fundamentally different experience than... I guess there could be a lot of different flavors of fear of heights maybe.
- AHAndrew Huberman
Mm-hmm.
- LFLex Fridman
But the one I have didn't seem to be connected to s- jumping out of a plane because they're very different, 'cause, like, once you accept that you're going to jump then it's, it's a different thing. I, I think what I'm afraid of is the moments before it is, is the mo- is the scariest part.
- AHAndrew Huberman
Absolutely.
- LFLex Fridman
And, and I, I don't think that's emphasized in the skydiving experience as much, and also just the acceptance of the fact that it's going to happen. So, so once you accept that it's going to happen, it's not as scary. It's the fact that it's not supposed to happen and it might, that's the scary part. That... I, I guess I'm not being eloquent in this des- description, but there's something about skydiving that, uh, was actually philosophically liberating. I was, it was... I was like, "Wow, it, it was, uh..." The possibility that you can walk on a surface and then at a certain point there's no surface anymore to walk on and it's all of a sudden the world becomes three-dimensional and there's this freedom of floating, that the concept of, like, of Earth disappears for a brief few seconds. I don't know. That was, that was...
- AHAndrew Huberman
Wild.
- LFLex Fridman
That was wild but I'm still terrified of heights,
- 17:48 – 22:48
Overcoming fears
- LFLex Fridman
so... I mean, one, one thing I, I wanna ask just on fear 'cause it's so fascinating is have you, um, learned anything about what it takes to overcome fears?
- AHAndrew Huberman
Yes. And that comes from two, from a, you know, research study standpoint, uh, two parallel tracks of research. One was done actually in mice, uh, 'cause we have a mouse lab also, c- where we can probe around different brain areas and try and figure out what interesting brain areas we might wanna probe around in humans. And a graduate student in my lab, she's now at Caltech, um, Lindsay Salé, um, published a paper back in 2018 showing that w- what at first might seem a little bit obvious, but the mechanisms are not, which is that there are really three responses to fear. You can pause, you can freeze essentially, um, you can retreat, you can back up, or you can go forward. And there's a single hub of neurons in the mid-brain, in the m- it's actually not the mid-brain, but it's, it's in the middle of the thalamus, which is a forebrain structure. Uh, and depending on which neurons are active there, there's a much higher probability that a mouse, or it turns out or a human will advance in the face of fear, or will pause or will, will retreat. Now that just assigns a neural structure to a behavioral phenomenon. But what's interesting is that it turns out that the lowest level of stress or autonomic arousal is actually associated with the pausing and freezing response.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Then as the threat becomes more impending, and we used visual looms in this case, the retreat response has a slightly higher level of autonomic arousal and stress. So think about playing hide and go seeking, you're trying to stay quiet in a, uh, in a closet that you're hiding. If you're very calm, it's easy to stay quiet and still. As your level of stress goes up, it's harder to maintain that level of quiet and stillness. You see this also in animals that are stalking. A cat will chatter its teeth. That's actually sort of top-down inhibition and trying to restrain behavior. So the freeze response is actually an active response, but it's fairly low stress. And what was interesting to us is that the highest level of autonomic arousal was associated with the forward movement toward the threat, so in your case, um, jumping out of the plane. However, the forward movement in the face of threat was linked to the activation of what we call collateral, which means just a side connection, literally a wire in the brain that connects to the dopamine circuits for reward. And so when one safely and adaptively, meaning you survive, moves through a threat or toward a threat, it's rewarded as a positive experience.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
And so the key, it actually maps very well to cognitive behavioral therapy and a lot of the existing treatments for trauma, is that you have to confront the thing that makes you afraid. So otherwise you exist in this very low level of reverberatory circuit activity where the, the circuits for autonomic arousal are humming and they're humming more and more and more. And we have to remember that, that stress and fear and threat were designed to agitate us so that we actually move. Th- so the reason I mention this is that I think a lot of times people think that the maximum, you know, stress response or fear response is to freeze and to lock up.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
But that's actually not the maximum stress response. The maximum stress response is to advance, but it's associated with reward. It has positive valence.
- LFLex Fridman
Oh, interesting word.
- AHAndrew Huberman
So it, so there's this kind of, everyone always thinks about the bell sh- you know, the sort of hump shape, uh, curve for, you know, at low levels of arousal performance is low and as it increases, performance goes higher and then it drops off as you get really stressed. But there's another bump further out the distribution-
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... where you perform very well under very high levels of stress. And so we've been spending a lot of time in humans and in animals exploring what it takes to get people comfortable to go to that place, and also to let them experience how there are heightened states of cognition there. There's, um, changes in time perception that allow you to evaluate your environment in fast, at a faster frame rate essentially. This is the matrix-
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... as a lot of people think of it.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Um, but we tend to think about fear as all the low level stuff where things aren't worked out, but there are many, um, there are a lot of different features to the fear response, and so we think about it quantitatively and we think about it from a circuit perspective in terms of outcomes and we try and weigh that against the threat. So we never want people to put themselves in unnecessary risk, but that's where the VR is fun because you can push people hard without risk of physically injuring them.
- LFLex Fridman
And that's, uh, like you said, it's a little bump. That, that seems to be a very small fraction of the human experience, right? So it's kind of fascinating to study it 'cause, um, most of us move through life without ever experiencing that kind of, uh, focus.
- 22:48 – 26:02
Optimal performance
- LFLex Fridman
- AHAndrew Huberman
Well, everything's in a peak state there. I really think that's where optimal performance lies.
- LFLex Fridman
There's so many interesting words here, but what's performance and what's optimal performance? We're talking about mental ability to, what, to perceive the environment quickly, to make actions quickly? What's optimal performance?
- AHAndrew Huberman
Yeah. Well, it's very subjective and it varies depending on, um, task and environment. So o- one way where we can make it a little bit more operational-
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... and concrete is to say, um, there is a sweet spot, if you will, where the level of internal autonomic arousal, AKA stress or alertness, whatever you want to call it, is ideally matched to the speed of whatever challenge you happen-
- LFLex Fridman
Got it. Yeah.
- AHAndrew Huberman
... to be facing in the outside world. So we all have, um, perception of the outside world as exteroception and the perception of our internal real estate, interoception. And when those two thi- when interoception and exteroception are matched along a couple dimensions, performance, uh, tends to increase, eh, or tends to be in, in an optimal range. So for instance, if you're ... I don't play guitar, but I know you play guitar. So let's say you're trying to learn something new on the guitar.I'm not saying that being in these super high states of activation are the best place for you to be in order to learn. It may be that you, your internal arousal needs to be at a level where your analysis of space and time has to be well-matched to the information coming in, and what you're trying to do in terms of performance, in terms of playing chords...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
... and notes and so forth. Now, in these cases of high threat where things are coming in quickly and animals and humans need to react very quickly, the higher your state of autonomic arousal, the better, because you're slicing time more finely just because of the way the autonomic system works. It, you know, the- the pu- pu- uh, pupil dilation for instance and movement of the lens essentially changes your- your optics. Now that's obvious. But in, with the change in optics is a change in how you bend time and slice time, which allows you to s- get more frames per second read out. With the guitar learning for instance, it might actually be that you wanna be almost sleepy.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Almost in a, uh, kind of drowsy state to be able to, uh, and I don't play music, so I can't...
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
I'm guessing here, but sense some of the nuance in the chords or the ways that you're, uh, to be relaxed enough that your fingers can follow an external queue. So matching the movement of your fingers to something that's pure exteroception.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
And so there is no perfect autonomic state for, uh, performance. This is why I don't favor terms like flow...
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... because they're not well operationally de- defined enough. But I do believe that optimal or peak performance is going to arise when internal state is ideally matched to the s- base time features of the external demands.
- LFLex Fridman
So there's so- some slicing of time that happens and then you're, you're able to adjust, s- slice time more finely or more, less finely in order to adjust to the, the stimulus, the dynamics of
- 26:02 – 41:27
Deep work
- LFLex Fridman
the stimulus. What about the, the realm of ideas? So like, you know, I'm, I'm a big believer... Uh, this guy named Cal Newport who wrote a book about Deep Work.
- AHAndrew Huberman
Oh, yeah. I love that book.
- LFLex Fridman
(laughs) Yeah, he's great. Uh, so, uh, he, uh, I mean, one of the nice things I've always practiced Deep Work but he, it's- it's always nice to have words, uh, put to the, the concepts that you've practiced. It somehow makes them more concrete, and allows you to, uh, to get better. It- it turns into a skill that you can get better at. But, you know, I also value deep thinking where you think... It's almost meditative. You think about a particular concept for long periods of time. The programming you have to do that kinda thing for. You just have to hold this concept like, like you- you hold it, and then you take steps with it, you take further steps, and you're- you're holding relatively complicated things in your mind as you're thinking about them. And there's a lot of... I mean, the hardest part is there's, uh, frustrating things like, you take a step and it turns out to be the wrong direction, so you have to calmly turn around and take a step back. And then, as you're kinda like exploring through the space of ideas, is there something about your study of optimal performance that could be applied to the act of thinking...
- AHAndrew Huberman
Mm-hmm.
- LFLex Fridman
... as opposed to action?
- AHAndrew Huberman
Well, we haven't done, uh, too much work there but what, um, but I think I can comment on it...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
... from a neuroscience perspective.
- LFLex Fridman
Yeah, what's your intuition about it?
- AHAndrew Huberman
Which is really all I do is that I...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Well, I mean, we do experiments in the lab but, um, looking at things through the lens of neuroscience. So what you're describing, um, can be mapped fairly well to working memory, just keeping things online and updating them as they change and information is coming back into- into your brain. Uh, Jack Feldman, who I'm a huge fan of and, um, fortunate to be friends with, is a, uh, professor at UCLA, works on respiration and breathing, but he has a physics background and, um, and so he thinks about respiration and breathing in terms of ground states and how they modulate other states, a very- very interesting and I think, um, important work. Jack, uh, has an answer to your question.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
So I'm not gonna get this exactly right 'cause this is lifted from a coffee conversation that we had...
- LFLex Fridman
(laughs)
- AHAndrew Huberman
... about a month ago but, uh, so, um, apologies in advance for the... But I think I can get it mostly right. So we were talking about this, about how the brain updates cognitive states depending on demands, and thinking in particular. And he used an interesting example, I'd be curious to know if you- you agree or disagree. Uh, he said, you know most great mathematics is done by people in their late teens and 20s.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
And even you could say early 20s. Sometimes into the late 20s but not much further on.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Maybe I just insulted some mathematicians but...
- LFLex Fridman
No, that's- that's- that's true.
- AHAndrew Huberman
And I think that it demands... His argument was, um, there's a tremendous demand on working memory to work out theorems in math, and to keep a number of plates spinning, so to speak, mentally, and run back and forth between them updating them. In physics, Jack said, and I- I'm in cl- I think this makes sense to me too, that there's a reliance on working memory but an increased reliance on some s- sort of deep, deep memory and deep memory stores, probably stuff that's moved out of the hippocampus and forebrain and into the cortex, and is, um, more, y- some episodic and declarative stuff but really so you're- you're pulling from your library basically...
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
It's not all RAM, it's not all working memory. And then in biology, the, and physicists tend to have very active careers into their, you know, 30s and 40s and 50s and so forth, um, sometimes later. And then in biology, you see careers that are, have a much longer arc. You get kind of these protracted (laughs) careers often, uh, people still in their 60s and 70s doing- doing really terrific work.... not always doing it with their own hands, 'cause there are people in the labs who are doing them, of course. But, um, and that work does tend to rely on insights gained from having a very deep knowledge base, where you can remember a paper and a, or maybe a figure in a paper, you could go look it up if you wanted to. But it's very different than the working memory of the mathematician. And so, when you're talking about coding or being in that tunnel of thought and trying to iterate and keeping a lot of plates spinning, it, it speaks directly to working memory. My lab hasn't done too much of that.
- LFLex Fridman
With working memory?
- AHAndrew Huberman
But we are pushing working memory when we have people do things like the simple lights out tasks while they're under ... We can increase the cognitive load by increasing the level of autonomic arousal to the point where they start doing less well.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And, you know, everyone has a cliff. This is what's kind of fun. We've had, um, you know, SEAL team operators come to the lab. We've had people from other units in the, uh, military very ... You know, we've had range of, of intellects and backgrounds and all sorts of things, and everyone has a cliff. And those cliffs, uh, sometimes show up as a function of s- the demands of speed of processing or how many things you need to keep online. I mean, we're all limited at some point in the number of things we can keep online. So what you're describing is very interesting because it, I think it has to do with how narrow or broad the information set is. Beca- And I don't program, I'm not a active programmer, so, um, this is a regime I don't really fully know, so I don't wanna comment about it, uh, in th- in any way, uh, that, you know, doesn't suggest that. But I think that what you're talking about is top-down control, so this is prefrontal cortex keeping every bit of reflexive circuitry at bay, the one that makes you wanna get up and use the restroom, the one that makes you wanna check your phone, the ... All of that, but also running these anterior thalamus to prefrontal cortex loops which we know are very important for working memory.
- LFLex Fridman
Yeah. Let, let me try to think through this a little bit. Uh, so, reducing the process of thinking to working memory access is tricky. It's probably ultimately correct, but if I were to say some of the most challenging things that, uh, an engineer has to do, and a sci- a scientific thinker, I would say it's kinda depressing to think that we do that best in our 20s, but is, uh, this kind of first principles thinking step of, of saying you, you're accessing the things that you know and then saying, "Well, let me ... How do I do this differently than I've done it before?" This, this weird, like, stepping back, like, "Is this right? Let's try it this other way." That, that's the most mentally taxing step is like y- you've gotten quite good at this particular pattern of how you solve this particular problem, so there's a, there's a pattern recognition first. You're like, "Okay, I know how to, how to build a thing that solves this particular problem," in programming, say. And then the question is, but can I do it much better? And I don't know if that's ... I don't know what the hell that is. I don't know if that's accessing working memory. That's, that's almost access ... Maybe it is accessing memory in the sense that it's trying to find similar patterns in a totally different place that it can be, uh, projected onto this. But you're, you're, it's ... You're not querying, uh, facts. You're querying, like, functional things, like ...
- AHAndrew Huberman
Yeah, it's patterns. I mean, you're running al-
- 41:27 – 45:13
Psychedelics
- AHAndrew Huberman
- LFLex Fridman
I wonder how to experiment with the mind without, without any medical assistance first. Like, you know, I, I push my mind in all kinds of directions. I definitely want to... I, I did, uh, shrooms a couple of times. I definitely want to, uh, figure out how I can experiment with, um, with psychedelics. I'm talking to, uh, Rick-... Domin, I think?
- AHAndrew Huberman
No, it's Doblin.
- LFLex Fridman
Doblin. Uh, soon (laughs) I em- went back and forth. So he does all these studies in psychedelics, and he keeps ignoring the parts of my email that asks like, "How do I participate in these studies?" (laughs)
- AHAndrew Huberman
Yeah. Well, there are some legality issues. I mean, the conversation... I wanna be very clear. I'm not saying that-
- LFLex Fridman
No.
- AHAndrew Huberman
... anyone should go out and do psychedelics.
- LFLex Fridman
No.
- AHAndrew Huberman
I think that drowsy states and sleep states are, are super interesting for accessing some of these more creative states of mind. Hypnosis is something that my colleague, David Spiegel, Associate Chair of Psychiatry at Stanford, works on, where also, again, it's a unique state because you have narrow context. So this is very, um, kind of tunnel vision and yet, deep really rela- excuse me, deeply relaxed, where new algorithms, if you will, can start to surface. Um, strong state for inducing neuroplasticity. And I think the... You know, so if I had a, um... I'm part of a group, um, that, uh, it's called the Liminal Collective. It's a group of people that get together and talk about, um, just wild ideas, but they try and implement.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Um, and it's a, it's a really interesting group. Some people from, uh, military, from, uh, Logitech, and some other backgrounds, academic backgrounds. And I was asked, you know, what would be... Um, if you could create a tool, if you just had a tool, like your magic wand wish for the day, what would it be? I thought it'd be really interesting if someone could develop psychedelics that have, um, on-off switches. So you could go into a psychedelic state very deeply for 10 minutes, but you could launch yourself out of that state and place yourself into a linear, real world state very quickly so that you could extract whatever it was that, that happened in that experience and then go back in if you wanted. Because the problem with psychedelic states and dream states is that, first of all, a lot of the reason people do them is they're lying. They say they want plasticity and they want all this stuff.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
They want a peak experience-
- LFLex Fridman
Yeah.
- AHAndrew Huberman
... inside of an amplified experience. So they're kind of seeking something unusual.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And I think we should just be honest about that.
- LFLex Fridman
Yep. Mm-hmm.
- AHAndrew Huberman
Because a lot of times, they're not trying to make their brain better, they're just trying to experience something really amazing. But the problem is space and time are so unlocked in these states, just like they are in dreams, that you can really end up with a whole lot of nothing. You can have an amazing amplified experience housed in an a- amplified experience and come out of that thinking you had a meaningful experience when you didn't bring anything back.
- LFLex Fridman
You didn't bring anything back.
- AHAndrew Huberman
Right.
- LFLex Fridman
All y- all you have is a fuzzy memory of having a transformational experience.
- AHAndrew Huberman
Right.
- LFLex Fridman
But you don't actually have-
- AHAndrew Huberman
It could be-
- LFLex Fridman
... yeah, tools to bring back or I just-
- AHAndrew Huberman
That's right.
- LFLex Fridman
Sorry, actual f- actually concrete ideas to bring back. Yeah, it's interesting. You shou- yeah, I wonder if it's possible to do that with the m- with the mind to, to be able to ho- hop back and forth, like-
- AHAndrew Huberman
Well, I think that's where the real power of, you know, adjusting states is gonna be. It probably will be with devices. Um, I mean, maybe it'll be done through pharmacology. It's just that it's hard to do on-off switches in, in human pharmacology that we have them for animals. I mean, we ha- we have, you know, Cre-Flip recombinases, and we have, um, you know, channelopsins and halorhodopsins, and, um, all these kinds of things. But to, to do that work in humans is tricky, but I think you could do it with, um, virtual reality, augmented reality, and other devices that bring more of the somatic experience
- 45:13 – 58:53
Deep work
- AHAndrew Huberman
into it.
- LFLex Fridman
You're, of course, a scientist who's studying humans as a collective. I tend to be just a, a one person scientist of just looking at myself. And, you know, I play... When these deep thinking, deep work sessions, I'm very cognizant, like in the morning, that there's times when my mind is so, like, eloquent at being able to jump around from ideas and hold them all together. And I, I'm almost like I step back from a third person perspective and enjoy that, whatever that mind is doing. I'm, I do not waste those moments. I... And I'm very conscious of, um, this like little creature that woke up, that's only awake for, if we're being honest, maybe a couple hours a day. Uh, if-
- AHAndrew Huberman
Early part of the day for you.
- LFLex Fridman
Early part of the day. Not always. Well, early part of the day for me is a very, uh, fluid concept. (laughs) So...
- AHAndrew Huberman
You're one of those.
- LFLex Fridman
Yeah, I'm one.
- AHAndrew Huberman
Yeah, you're one of those.
- LFLex Fridman
So, being single, one of the problems, single and no meetings, I don't schedule any meetings. I, I will... I've been living, uh, like a 28-hour day. So I just, I like, I, uh, it drifts. So it's, it's all over the fr- uh, the, the place. But after, uh, a, uh, traditionally defined full night sleep, (laughs) uh, whatever the heck that means, I, I find that like in, in those moments, there's a clarity of mind that's just... That's everything is effortless and it's the, it's the deepest dives intellectually that I make. And I, uh, I'm cognizant of it, and I try to bring that to the other parts of the day that don't have it and treasure them even more in those moments, 'cause they only last like 5 or 10 minutes. Uh, 'cause, of course, in those moments, you wanna do all kinds of stupid stuff that are completely is, is, is worthless, like check social media or something like that. But those are the most precious things in, in an i- in an intellectual life, is those mental moments of clarity. And I wonder... I'm learning how to control them. I think caffeine is somehow involved. I'm not sure exactly.
- AHAndrew Huberman
Sure. Well, because if, if you learn how to titrate caffeine, and everyone's slightly different with this, uh, what they need, but if you learn to titrate caffeine with time of day and the kind of work that you're trying to do, you can bring that autonomic arousal state into a, the close to perfect place.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And then you can tune it in with, you know... Sometimes people want a little bit of background music, sometimes they want less, these kinds of things. The, the, the early part of the day is interesting because the, um, one thing that's not often discussed is this transition out of sleep. So there's a, a book, um, I think it's called Winston Churchill's Nap, and it's about naps and, and the transition between wake and sleep as a valuable period. Um, I've...Uh, a long time ago, um, someone who I respect a lot was mentoring me, said, um, "Be very careful about bringing in someone else's sensory experience early in the day." So when I wake up, I'm very drowsy. I sleep well, but I, I don't emerge from that very quickly. I need a lot of caffeine to wake up and whatnot. But there's this concept of getting the download from sleep.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Which is, you know, in sleep, you're, uh, you were essentially expunging the things that you don't need.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
The stuff that's meaningless from the previous day. But you were also running variations on these algorithms of whatever it is you're trying to work out in life on short timescales, like the previous day, and long timescales, like your whole life. (laughs) And those lateral connections in layer five of the, of the neocortex are very robustly, um, active and, uh, across sensory areas, and, and you're running a, an algorithm or a colle- you know, a brain, it's a brain state that would be useless and waking. You wouldn't get anything done. You'd be the person talking to yourself in the hallway or something about something that no one else can see. But in those states, you do the, the theory is that you arrive at certain solutions and those solutions will reveal themselves in the early part of the day.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Unless you interfere with them by bringing in, social media is a good example, of you immediately enter somebody else's spacetime sensory relationship. Someone is the conductor of your thoughts in that case. And so many people have written about this. Um, what I'm saying isn't entirely new, but, but allowing the download to occur in the early part of the day and, and asking the question, am I more in my head or external? Am I in more of an interoceptive or exteroceptive mode? And depending on the kind of work you need to do, if it's, it sounds like for you, it's very interoceptive in the end, very... you got a lot of thinking going on and a lot of computing going on. Allowing yourself to transition out of that sleep state and arrive with those solutions from sleep and plug into the work really deeply.
- LFLex Fridman
Oh, yeah.
- AHAndrew Huberman
And then, and only then allowing things like music, news, social media, doesn't mean you shouldn't talk to loved ones and see faces and things like that, but some people have taken this to the extreme. When I was a graduate student at Berkeley, there was a guy, um, there was a professor, brilliant, odd, but brilliant, um, who was so fixated on this concept that he wouldn't look at faces in the early part of the day.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
Because he just didn't want to, anything else to impact him. Now, he would, didn't have the most, um, rounded life, (laughs) I suppose. But if you're talking about, um, cognitive performance, this could be actually be very beneficial.
- LFLex Fridman
You said so many brilliant things. So one, if you read books that describe the habits of, um, brilliant people like, uh, writers, they do control their sensory experience in, in the w- in the, in the hours after wake. Like many writers, you know, they have a particular habit of several hours early in the morning of actual writing. They don't do, don't do any- anything else for the rest of the day, but they control, they're very sensitive to noises and so on. I think they make it very difficult to live with them. I try to... I'm definitely like that, like I could, I- I love to control the sensory, uh, how much information is, is coming in. There's something about the peaceful, just everything being peaceful. At the same time, and we were talking to a mutual friend of Whitney Cummings, who, um, has, has a, has a mansion, a castle on top of a cliff in, in the middle of nowhere. She actually purchased her own island. Uh, so she wants silence. She wants to control how much, uh, uh, s- sound is coming in.
- AHAndrew Huberman
She's very sensitive to, to sound and environment.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
Yeah, beautiful home and environment, but like clearly puts a lot of attention into-
- LFLex Fridman
Just quiet.
- AHAndrew Huberman
... details, yeah. And, and very creative.
- LFLex Fridman
Yeah. And that's-
- AHAndrew Huberman
Yeah.
- LFLex Fridman
Yeah, that allows for creativity to flourish. I'm also... I don't like, that feels like a slippery slope. So I, I enjoy introducing, uh, noises and signals and, uh, training my mind to be able to tune them out. 'Cause I feel like you can't always control the environment so perfectly because, uh, because your mind gets comfortable with that. I think it's a skill that you want to learn to be able to sh- shut it off. Like, I often go to like back before COVID to a coffee shop. It really annoys me when there's sounds and voices and so on, but I feel like I can train my mind-
- 58:53 – 1:06:11
Everything in the brain is an abstraction
- AHAndrew Huberman
the day, yeah.
- LFLex Fridman
C- can you linger just briefly on, 'cause you use this term a, a lot, and it'd be nice to try to get a little more color to it, which is interoception and exteroception, uh, wha- uh, what are we, what are we exactly talking about? So like, what's included in each category and how much overlap is there?
- AHAndrew Huberman
Interoception would be, uh, an awareness of anything that's within the confines or on the surface of my skin that I'm sensing.
- LFLex Fridman
Oh, so literally physiological, like-
- AHAndrew Huberman
Physiological, like within the boundaries of my skin and probably touch to the skin as well. Exteroception would be perception of anything that's ex- beyond the reach of my skin, so the, that bottle of water, um, a, a scent, um, a sound, although it... And this can change dramatically actually. If you have headphones in, you tend to hear things in your head if-
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
... as opposed to a speaker in the room.
- LFLex Fridman
It's interesting, yeah.
- AHAndrew Huberman
This is actually the basis of ventriloquism. So there are beautiful experiments done by Gregg Rechenzon up at UC Davis looking at how auditory and visual cues are matched, and we have an array of speakers, and you can, uh, this will become obvious as I say it, but, you know, obviously, the ventriloquist doesn't throw their voice. What they do is they direct your vision to a particular location, and you think the sound is coming from that location.
- LFLex Fridman
Yeah.
- AHAndrew Huberman
And there are beautiful experiments that Gregg and his colleagues have done where they suddenly introduce a auditory visual mismatch, and it freaks people out because you can actually make it seem, from a perception standpoint, as if the sound arrived from the corner of the room and hit you, like, i- physically.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
And, and people will recoil. And so sounds aren't getting thrown across the room. They're still coming from this defined location, an array of speakers, but this is the way the brain creates these internal representations and-... again, not to, I don't wanna go down a rabbit hole, but, um, I think as much as you're, you know, I'm sure the listeners appreciate this, but, you know, everything in the brain is an abstraction, right? I mean, they're, they're... The sensory apparati, they are the eyes and ears and nose and skin and taste and all that, are taking information, and with interoception, it's taking information from sensors inside the body, the enteric nervous system for the gut. I've got, uh, sensory neurons that inner make my liver, um, et cetera, taking all that, and the brain is abstracting that in the same way that if I took a picture of your face and I handed it to you and I'd say, "That's you," you'd say, "Yeah, that's me." But if I were an abstract artist, I'd be doing a little bit more what the brain does, where if I took a pen and... pad and paper, maybe I could do this 'cause I'm a terrible artist, and I could just mix it up and I'd, let's say I would make your eyes like water bottles, but I'd flip them upside down, and I'd start assigning fruits and objects to the different features...
- LFLex Fridman
Yeah.
- AHAndrew Huberman
... of your face and I showed it to you, I'd say, "Lex, that's you," you'd say, "Well, that's not me," and I'd say, "No, but that's my abstraction of you."
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
But that's what the brain does. The spacetime relationship of the neurons that fire that encode your face hasn't... have no resemblance to your face.
- LFLex Fridman
Right. And then they, they form the...
- AHAndrew Huberman
(laughs) And I think people don't really, uh, I don't know if people have fully internalized that, but the day...
- LFLex Fridman
Of course.
- AHAndrew Huberman
... that I... And I'm not sure I fully internalized that because it's weird to think about, but all neurons can do is fire in space and in time. Different neurons in different sequences, perhaps with different intensities.
- LFLex Fridman
Mm-hmm.
- AHAndrew Huberman
It's not clear the action potential is all or none, although people, neuroscientists don't like to talk about that even though it's been published in Nature a couple of times. The action potential for a given neuron doesn't always have the exact same waveform. People...
- LFLex Fridman
Oh, interesting.
- AHAndrew Huberman
It's in all the textbooks, but you can modify that waveform.
- LFLex Fridman
Well, the, the, uh... (laughs) I mean, there's a lot of fascinating stuff with, uh, with neuroscience about the fuzziness of all the, uh, uh, o- of the transfer of information from neuron to neuron. I mean, the, we, we certainly touch upon it every time we at all try to think about the difference between artificial neural networks and biological neural networks. But can we, uh, maybe linger a little bit on this, uh, on this circuitry that you're getting at? So the brain is just a bunch of stuff firing and it forms abstractions that are fascinating and beautiful, like layers upon layers upon layers of abstraction. And I think it, uh, just like when you're programming, you know, I'm programming in Python, it's, uh, it's awe-inspiring to think that underneath it all, it ends up being zeros and ones. And the computer doesn't know about those stupid Python or Windows or Linux. It, it only knows about the zeros and ones. In the same way with the brain, is there something interesting to you or fundamental to you about the circuitry of the brain that allows for the magic that's in our mind to emerge? How much do we understand, I mean, maybe even focusing on the vision system, is, is there something specific about the structure of the vision system, the circuitry of it, that, uh, allows for the complexity of the vision system to emerge? Or is it all just a complete chaotic mess that we don't understand?
- AHAndrew Huberman
It's definitely not all a chaotic mess that we don't understand, if we're talking about vision. (laughs)
- LFLex Fridman
(laughs) Okay, let's stick-
- AHAndrew Huberman
And that's not just 'cause I'm a vision scientist, but...
- LFLex Fridman
Let's stick to vision as well.
- 1:06:11 – 1:17:47
Human vision system
- LFLex Fridman
those yet.
- AHAndrew Huberman
Yeah, the visual system is amazing. We're mostly visual animals. To navigate, t- survive, humans mainly rely on vision, not smell or something else. But, um, it's a filter for cognition, and it's a, it's a strong driver of cognition. M- maybe just 'cause it came up and then, uh, we're moving to higher level concepts. I just... The, the way the visual system works can be summarized in a, um, in a few relatively succinct statements, unlike most of what I've said, which has not been succinct at all.
- LFLex Fridman
Let's go there. What, uh, what-
- AHAndrew Huberman
You know, the, the retina...
- LFLex Fridman
... what's, what's involved?
- AHAndrew Huberman
Yeah, so the retina is this-... three layers of neuron structure at the back of your eye, it's about as thick as a credit card. It is a piece of your brain, and sometimes people think I'm kind of wriggling by, out of, uh, reality by saying that. It is, it's absolutely a piece of the brain, it's- it's a forebrain structure that in the first trimester, there's a genetic program that made sure that that neural retina, which is part of your central nervous system, was squeezed out into what's called the embryonic eye cups, and that the bone formed with a little hole where the optic nerve is gonna connect it to the rest of the brain. And those, that window, uh, into the world is the only window into the world for a, for a mammal which has a thick skull. Birds have a thin skull, so their pineal gland sits... And lizards too, and snakes actually have a hole so that light can make it down into the pineal directly and then train melatonin rhythms for time of day and time of year. Humans have to do all that through the eyes. So three layers of neurons that are a piece of your brain, they are a central nervous system, and the optic nerve connects to the rest of the brain. The neurons in the eye, some just care about luminance, just how bright or dim it is...
- NANarrator
Mm-hmm.
- AHAndrew Huberman
... and they inform the brain about time of day, and then the central circadian clock informs every cell in your body about time of day and makes sure that all sorts of good stuff happens if you're getting light in your eyes at the right times.
- NANarrator
Mm-hmm.
- AHAndrew Huberman
And all sorts of bad things happen if you are getting light randomly throughout the 24-hour cycle. We could talk about all that, but this is a good incentive for keeping a relatively normal schedule, a consistent schedule...
- NANarrator
You lost me.
- AHAndrew Huberman
... of light exposure.
- NANarrator
(laughs)
- AHAndrew Huberman
Con- consistent schedule.
- NANarrator
Okay.
- AHAndrew Huberman
Try and keep a consistent schedule. When you're young, it's easy to go off schedule and recover. As you get older, it gets harder, but you see everything from outcomes in cancer patients to, oh, um, diabetes in, um, you know, improves when people are getting light at a particular time of day and getting darkness at a particular phase of the 24-hour cycle. We were des- designed to, um, get light and dark at different times of the c- of the circadian cycle. That's all being, all that information is coming in through a specialized type of neuron in the retina called the melanopsin, an intrinsically photosensitive ganglion cell discovered by David Berson at Brown University. That's not spatial information, it's subconscious, you don't think, "Oh, it's t- daytime." Even if you're looking at the sun, it doesn't matter, it's a photon counter. It's literally counting photons. And it's saying, "Oh, even though it's a cloudy day, lots of photons coming in. Ah, it's winter in Boston, it must be winter," and your system is a little depressed. It's spring and you feel alert. That's not a coincidence. That's these melanopsin cells signaling the circadian clock. There are a bunch of other neurons in the eye that signal to the brain, and they mainly signal the presence of things that are lighter than background or darker than background. So a black object would be darker than background, a light object, lighter than background, and that all com- it's mainly a pi- it's looking at pixels, mainly, it's loo- they look at circles, and those neurons have receptive fields, which not everyone will understand, but those neurons respond best to little circles of dark light or little circles of bright light.
- NANarrator
Mm-hmm.
- AHAndrew Huberman
Little circles of red light versus l- little circles of green light or blue light. And so it sounds very basic, it's like, red, green, blue, and circles, brighter or dimmer than what's next to it, but that's basically the only information that's sent down the optic nerve.
- NANarrator
Mm-hmm.
- AHAndrew Huberman
And when we say information, we can be very precise. I don't mean little bits of red traveling down the optic nerve, I mean spikes, neural action potentials...
- NANarrator
Mm-hmm.
- AHAndrew Huberman
... in space and time, which for you is like makes total sense, but I think for a lot of people, it's, uh, it's actually beautiful to think about. All that information in the outside world is converted into a language that's very simple, it's just like a few syllables, if you will.
- NANarrator
Mm-hmm.
- AHAndrew Huberman
And those syllables are being shouted down the optic nerve, converted into a totally different language like Morse code.
- NANarrator
Mm-hmm.
- AHAndrew Huberman
Beep, beep, beep, beep, beep.
- NANarrator
Yeah.
- AHAndrew Huberman
Goes into the brain, and then the thalamus essentially responds in the same way that the retina does, except the thalamus is also weighting things. It's saying, "You know what? That thing, um, was moving faster than everything else, or it's brighter than everything else, so that signal, I'm gonna get up, I'm gonna allow up to cortex." Or, "That signal is much redder than it is green, so I'm gonna let that signal go through. That signal is much, eh, it's kind of more like the red next to it, throw that out."
- NANarrator
Mm-hmm.
- AHAndrew Huberman
The information just doesn't get up into your cortex. And then in cortex, of course, is where perceptions happen, and in V1, if you will, visual area one, but also some neighboring areas, you start getting representations of things like oriented lines. So there is a neuron that responds to this angle of my hand versus vertical.
- 1:17:47 – 1:45:17
Neuralink
- NANarrator
- AHAndrew Huberman
There's no abstractions.
- NANarrator
Yeah.
- AHAndrew Huberman
And this is why I, um, you know, I know we have some common friends at Neuralink, and I love the demonstration they did recently, I'm a huge fan of what they're doing and, and where they're headed. And no, I don't get paid to say that, and I have no, uh, you know, business relationship to them. I'm just a huge fan of the people and the mission. But my question was to some of them, you know, when are you gonna go subcortical? 'Cause if you want to control an animal, you don't do it in the cortex. The cortex is like the abstract painting I made of your face. It, stim, moving, removing one piece or changing something may or may not matter for the abstraction, but when you are in the subcortical areas of the brain, a stimulating electrode can evoke an entire behavior or an entire state. And so the brain, if we're gonna have a discussion about the brain and how the brain works, we need to really be clear which brain, because everyone loves neocortex. It's like, oh, canonical circuits and cortex, we're gonna get the cortical connectome. And sure, necessary, but not sufficient, not to be able to plug in patterns of electrical stimulation and get behavior. Eventually we'll get there. But if you're talking subcortical circuits, that's where the action is, that's where you could potentially cure Parkinson's by stimulating the subthalamic nucleus, because we know that it gates motor activation patterns in very predictable ways. So I think for those that are interested in neuroscience, it pays to pay attention to, like, is this a circuit that ab- abstracts the sensory information, or is it just one that builds up...... hierarchical models in a very predictable way, and there's a huge chasm in neuroscience right now, because there's no conceptual leadership. No one knows which way to go. And this is why I think Neuralink has captured an amazing opportunity, which was, okay, while, while all you academic research labs are figuring all this stuff out, we're gonna pick a very specific goal and make the goal the end point. And some academic laboratories do that, but I think that's a beautiful way to attack this whole thing about the brain, because it's very concrete. Let's restore motion to the Parkinsonian patient. Academic labs do that, want to do that too, of course. Let's restore, um, speech to the stroke patient.
Episode duration: 2:32:14
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