Essentials: The Neuroscience of Speech, Language & Music | Dr. Erich Jarvis

In this Huberman Lab Essentials episode, my guest is Dr. Erich Jarvis, PhD, a professor and Head of the Laboratory of Neurogenetics of Language at Rockefeller University and an investigator at the Howard Hughes Medical Institute (HHMI). We discuss the brain circuits and genes underlying spoken language and why the ability to learn and produce vocalizations is extraordinarily rare in the animal kingdom. We also explore why song likely evolved before language, how gesture and movement share deep neural roots with speech, the neurobiology of stuttering, why childhood is the optimal window for language acquisition, and how physical movement — including dance — may help preserve speech and cognitive function across a lifetime. Read the show notes at hubermanlab.com. Thank you to our sponsors AG1: https://drinkag1.com/huberman Function: https://functionhealth.com/huberman Eight Sleep: https://eightsleep.com/huberman Timestamps (00:00:00) Speech & Language (00:00:23) Speech vs. Language; Brain Pathways for Communication (00:01:57) Gesture, Hand Movement & Speech Evolution (00:04:31) Sponsor: Function (00:05:59) Innate Vocalizations vs. Learned Speech (00:08:01) Evolution of Spoken Language; Neanderthals & Vocal Learning (00:09:29) Birdsong & Human Speech; Brain Circuit Parallels (00:13:22) Hummingbirds; Vocal Learning Species & Complex Traits (00:14:32) Critical Periods & Learning Your Native Song (00:16:50) Pidgin Language & Cultural-Genetic Convergence (00:18:36) Sponsor: AG1 (00:20:01) Genes Specialized in Speech Circuits (00:23:05) Critical Period for Language Learning; Multilingualism (00:25:17) Music, Emotion & Semantic vs. Affective Communication (00:28:14) Sponsor: Eight Sleep (00:29:49) Facial Expression & Speech Circuitry (00:31:07) Written Language & Neural Pathways (00:32:47) Stuttering; Basal Ganglia & Neurobiological Basis (00:35:03) Texting & Language Evolution (00:36:36) Tool: Movement, Dancing & Singing to Maintain Cognitive Health (00:38:43) Recap Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Andrew D. Huberman?

  Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. And now, for my discussion with Dr. Eric Jarvis. Eric, so great to have you here.

• 0:22Speaker 01

  Thank you.

• 0:23Andrew D. Huberman?

  Very interested in learning from you about speech and language. In terms of the study of speech and language, and thinking about how the brain organizes speech and language, what are the similarities? What are the differences? How should we think about speech and language?

• 0:38Speaker 01

  There really isn't such a sharp distinction. And let me tell you how some people think of it now, that there's a separate language module in the brain that has all the algorithms and computations that influence the speech pathway on how to produce sound, and the auditory pathway on how to perceive and interpret it for speech, or for, you know, sound that we call speech. I don't think there is any good evidence for a separate language module. Instead, there is a speech production pathway that's controlling our larynx, controlling our jaw muscles, that has built within it all the complex algorithms for spoken language. And there's the auditory pathway

• 1:23Speaker 01

  that has built within it all the complex algorithms for understanding speech, not separate from a language module. And this speech production pathway is specialized to humans, and parrots, and songbirds, whereas this auditory perception pathway is more ubiquitous amongst the animal kingdom. And this is why dogs can understand "sit", "siéntese", "come here, boy", "get the ball", and so forth. Dogs can understand several hundred human speech words. Great apes, you can teach them for several thousand, but they can't say a word.

• 1:57Andrew D. Huberman?

  What do we understand about modes of communication that are... Like language, but might not be what would classically be called language.

• 2:06Speaker 01

  Yes, right. So next to the brain regions that are controlling spoken language are the brain regions for gesturing with the hands. And that hand parallel pathway has also complex algorithms that we can utilize. And some species are more advanced in these circuits, whether it's sound or gesturing with hands, and some are less advanced. Humans are the most advanced at spoken language, but not necessarily as big a difference at gestural language compared to some other species. So as you and I are talking here today, and people who are listening but can't see us, we're actually gesturing with our hands as we talk, without knowing it, or doing it unconsciously. And if we were talking on

• 2:51Speaker 01

  a telephone, I would have one hand here and I'd be gesturing with the other hand, without even you seeing me, right? And so why is that? Some have argued, and I would agree, but based upon what we've seen, is that there's an evolutionary relationship between the brain pathways that control speech production and gesturing. And the brain regions I mentioned are directly adjacent to each other. And why is that? I think that the brain pathways that control speech evolved out of the brain pathways that control body movement. All right. And that's, when you talk about Italian, French, English, and

• 3:29Speaker 01

  so forth, each one of those languages come with a learned set of gestures that you can communicate with. Now, how is that related to other animals? Well, Coco, a gorilla, who was raised with humans for 39 years, or more, learned how to do gesture, communication, learn how to sign language, so to speak, right? But Coco couldn't produce those sounds. Coco could understand them as well. By seeing somebody sign or hearing somebody produce speech. But Coco couldn't produce it with her voice. And so what's going on there is that a number of species, not all of them.

• 4:11Speaker 01

  A number of species have motor pathways in the brain where you can do, learn, gesturing, rudimentary language, if you wanted, say, with your limbs, even if it's not as advanced as humans. But they don't have this extra brain pathway for the sound. So they can't gesture with their voice in the way that they gesture with their hands.

• 4:31Andrew D. Huberman?

  I'd like to take a quick break and acknowledge our sponsor, Function. Function provides over 160 advanced lab tests to give you a clear snapshot of your bodily health. This snapshot gives insights into your heart health, hormone health, autoimmune function, nutrient levels, and much more. They've also recently added access to advanced MRI and CT scans. Function not only provides testing of over 160 biomarkers key to your physical and mental health, it also analyzes these results and provides recommendations for improving your health from top doctors. For example, in a recent test with Function, I learned that some of my blood lipids were slightly out of range. As a result, I decided to start supplementing with nattokinase, which can naturally help reduce LDL cholesterol, and it did.

• 5:15Andrew D. Huberman?

  In a follow-up test, I could confirm that this strategy worked. My blood lipids are now back where I want them, in range. Comprehensive lab testing of the sort that Function offers is so important for health. And while I've been doing it for years, it's always been overly complicated and expensive. But now with Function, it's extremely easy and affordable. To learn more, visit functionhealth.com/huberman and use the code HUBERMAN for a $50 credit towards your membership. One thing that I've wondered about for a very long time is whether or not primitive emotions and primitive sounds are the early substrate of language. When I smell something delicious, I typically inhale more and I might say, mm.

• 6:01Andrew D. Huberman?

  Or something like that. Whereas if I smell something putrid, I typically turn away, I wince, and I will exhale, trying to not ingest those molecules or inhale those molecules. I could imagine that these are the basic dark and light contrasts of the language system. This kind of primitive to more sophisticated pyramid of of sound to language. Is this a crazy idea? Do we have any, do we have any evidence this is the way it works?

• 6:30Speaker 01

  No, it's not a crazy idea. And in fact, you hit upon one of the key distinctions in the field of research that I started out in, which is vocal learning research. Most vertebrate species vocalize, but most of them are producing innate sounds that they're born with. That is babies crying, for example, or dogs barking. And only a few species have learned vocal communication, the ability to imitate sounds. And that is what makes spoken language special. When people think of what's special about language, it's the learned vocalizations. That is what's rare. So all the things you talked about, the breathing, the grunting and so forth, a lot of that is handled by the brainstem circuits,

• 7:13Speaker 01

  you know, right around the level of your neck and below, like a reflex kind of thing. So or or even some emotional aspects of your behavior in the hypothalamus and so forth. But for a learned behavior, learning how to speak, learning how to play the piano, teaching a dog to learn how to do tricks is using the forebrain circuits. And what has happened is that there's a lot of forebrain circuits that are controlling learning how to move body parts in these species, but not for the vocalizations. But in humans and in parrots and some other species, somehow we acquired circuits where the forebrain has taken over the brainstem.

• 7:54Speaker 01

  And now using that brainstem not only to produce the innate behaviors or vocal behaviors, but the learned ones as well.

• 8:01Andrew D. Huberman?

  Do we have any sense of when? Modern or sophisticated language evolved?

• 8:07Speaker 01

  Amongst the primates, which we humans belong to, we are the only ones that have this advanced vocal learning ability.

• 8:15Speaker 01

  Now, when you, it was assumed that it was only Homo sapiens.

• 8:21Speaker 01

  Then you can go back in time now, based upon genomic data, not only of us living humans, but of the fossils that have been found for Homo sapiens, of Neanderthals, of Denisovan individuals, and discover that our ancestor, our human ancestors, supposedly hybridized with these other hominid species. And it was assumed that these other hominid species don't learn how to imitate sounds. I don't know of any species today that's a vocal learner that can have children with a non-vocal learning species. I don't see it. It doesn't mean it didn't exist. And when we look at the genetic data from these ancestral hominids,

• 9:06Speaker 01

  that, you know, where we can look at genes that are involved in learned vocal communication, they have the same sequence as we humans do for genes that function in speech circuits. So I think Neanderthals had spoken language. I'm not going to say it's as advanced as what it is in humans, I don't know. But I think it's been there for at least between 500,000 to a million years.

• 9:29Andrew D. Huberman?

  Maybe we could talk a little bit more about the overlap between brain circuits that control language and speech in humans and other animals. You know, I was weaned in the neuroscience era where bird song and the the ability of birds to learn their tutor's song was and still is a prominent field, a subfield of neuroscience. And this notion of a critical period, a time in which language is learned more easily than it is later in life.

• 9:57Andrew D. Huberman?

  The names of the different brain areas were quite different. It one opens the textbooks, we hear Veroniques and Broca's for the humans. And you look at the bird stuff, I remember, you know,

• 10:07Speaker 01

  HPC.

• 10:08Andrew D. Huberman?

  Robust archetom, area X.

• 10:10Speaker 01

  That's right, yeah.

• 10:11Andrew D. Huberman?

  How similar or different are the brains, brain areas controlling speech and language? And say, a songbird and a young child, human child?

• 10:19Speaker 01

  Yeah, so going back to the 1950s or even a little earlier, and Peter Moller and others who got involved in neuroethology, the study of neurobiology of behavior in a natural way, right? You know, they started to find that behaviorally, there are these species of birds, like songbirds and parents. And now we also know hummingbirds, just three of them, out of the 40 something bird groups out there on the planet, orders, that they can imitate sounds like we do. And so that was a similarity. In other words, they had this kind of behavior that's more similar to us than chimpanzees have with us or than chickens have with them, right? They're close to relatives. And then they discovered even more similarities,

• 11:02Speaker 01

  these critical periods, that if you remove a child, you know, this unfortunately happens where a child is feral and is not raised with human and goes through their puberty phase of growth, it becomes hard for them to learn a language as an adult. So there's this critical period where you learn best. And even later on, when you're in regular society, it's hard to learn. Well, the birds undergo these same things. And then it was discovered that if they become deaf, we humans become deaf, our speech starts to deteriorate without any kind of therapy. If a non-human primate or, you know, or let's say a chicken becomes deaf, their vocalizations don't deteriorate, very little at least.

• 11:47Speaker 01

  Well, this happens in the vocal learning birds. So there were all these behavioral parallels that came along with a package. And then people looked into the brain. Fernando Nadavam, my former PhD advisor, and began to discover the area X you talked about, the robust nucleus of the archipelium. And And these brain pathways were not found in the species who couldn't imitate. So there was a parallel here. And then, jumping many years later, you know, I started to dig down into these brain circuits to discover that these brain circuits have parallel functions with the brain circuits for humans, even though they're by a different name like barocas and laryngomotor cortex.

• 12:27Speaker 01

  And most recently, we discovered not only the actual circuitry and the connectivity are similar, but the underlying genes that are expressed in these brain regions in a specialized way, different from the rest of the brain, are also similar between humans and songbirds and parrots. So all the way down to the genes, and now we're finding the specific mutations are also similar, not always identical, but similar, which indicates remarkable convergence for a so-called complex behavior in species separated by 300 million years from the common ancestor. And not only that, we are discovering that mutations in these genes that cause speech deficits in humans, like in FoxP2,

• 13:10Speaker 01

  if you put those same mutations or similar type of deficits in these vocal learning birds, you get similar deficits. So convergence of the behavior is associated with similar genetic disorders of the behavior. Do hummingbirds sing or do they hum? Hummingbirds hum with their wings and sing with their ser rings. In a coordinated way? In a coordinated way. There's some species of hummingbirds that actually will, Doug Ashworth showed this, that will flap their wings and create a slapping sound with their wings that's in unison with their song. And you would not know it, but it sounds like a particular syllable in their songs,

• 13:52Speaker 01

  even though it's their wings and their voice at the same time. Hummingbirds are clapping to their song? Clapping, but they're snapping their wings together in unison with a song to make it like, if I'm going, ba da da da da, ba da. You know, and I banged on the table. Except they make it almost sound like their voice with their wings. What's amazing about hummingbirds, and I were gonna say vocal learning species in general, is that for whatever reason, they seem to evolve multiple complex traits. You know, this idea that the evolving language, spoken language in particular, comes along with a set of specializations.

• 14:31Andrew D. Huberman?

  When I was coming up in neuroscience, I learned that, I think it was the work of Peter Marler, that young birds learn, songbirds, learn their tutor's song and learn it quite, quite well. But that they could learn the song of another tutor. In other words, they could learn a different, and for the listeners, I'm doing air quotes here, a different language, a different bird's song, different than their own species song. But never as well as they could learn their own natural genetically linked song.

• 15:05Speaker 01

  Yes.

• 15:05Andrew D. Huberman?

  Genetically linked, meaning that it would be like me being raised in a different culture and that I would learn the other language, but not as well as I would have learned English. This, this is the idea.

• 15:17Speaker 01

  Yes.

• 15:17Andrew D. Huberman?

  Is that true?

• 15:18Speaker 01

  That is true, yes. And that's, and that's what I learned growing up as well and, and talked to Peter Marler himself about before he passed. He had this, he used to call it the innate predisposition to learn. All right, so, um, which would be kind of the equivalent in the linguistic community of universal grammar. There is something genetically influencing our vocal communication on top of what we learn culturally. And so there's this balance between the genetic control of speech or a song in these birds and the learned cultural control. And so, so yes, if you were to take, um, you know, um, I mean, in this case, we, we actually

• 16:01Speaker 01

  tried this at Rockefeller later on, take a zebra finch and raise it with a canary, it would sing a song that was sort of like a hybrid in between. We call it a caninch, right?

• 16:14Speaker 01

  And vice versa for the canary. Because there's something different about their vocal musculature or the circuitry in the brain. And with a zebra finch, even with a closely related species, if you would take a zebra finch, a young animal, and in one cage next to it, place its own species, adult male, right? And in the other cage, place a Bengalese finch next to it, it would preferably learn the song from its own species neighbor. But if you remove its neighbor, it would learn that Bengalese finch very well.

• 16:45Andrew D. Huberman?

  Fantastic.

• 16:46Speaker 01

  So there's, it has something to do with also the social bonding with your own species.

• 16:50Andrew D. Huberman?

  That raises a question that I, based on something I also heard, but I don't have any scientific, peer-reviewed publication to point to, which is this idea of pidgin. Not the bird, but this idea of when multiple cultures and languages converge in a given geographic area, that the children of all the different native languages will come up with their own language. I think it was in island culture, maybe in Hawaii, called pidgin, which is sort of a hybrid of the various languages that their parents speak at home and that they themselves speak. And that somehow pidgin, again, not the bird, but a language called pidgin, for reasons I don't know, harbors certain basic elements of all language. Is that true?

• 17:35Andrew D. Huberman?

  Is that not true?

• 17:36Speaker 01

  What is going on here is cultural evolution remarkably tracks genetic evolution. So if you bring people from two separate populations together that have been in their separate populations, evolutionarily at least, for hundreds of generations. So someone's speaking Chinese, someone's speaking English. And that child then is learning from both of them. Yes, that child's going to be able to pick up and merge phonemes and words together in a way that an adult wouldn't. Because why they're experiencing both languages at the same time during their critical period of years

• 18:18Speaker 01

  in a way that adults would not be able to experience? And so you get a hybrid. And the lowest common denominator is going to be what they share. And so the phonemes that they've retained in each of their languages is what's going to be, I imagine, used the most.

• 18:36Andrew D. Huberman?

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• 19:21Andrew D. Huberman?

  what would that supplement be? And my answer is always AG1, because it has just been oh so critical to supporting all aspects of my physical health, mental health, and performance. I know this from my own experience with AG1, and I continually hear this from other people who use AG1 daily. If you would like to try AG1, you can go to drinkag1.com/huberman to get a special offer. For a limited time, AG1 is giving away six free travel packs of AG1 and a bottle of vitamin D3K2 with your subscription. Again, that's drinkag1 with the numeral 1.com/huberman to get six free travel packs and a bottle of vitamin D3K2 with your subscription. So we've got brain circuits in songbirds and in humans that in many ways are similar,

• 20:06Andrew D. Huberman?

  perhaps not in their exact wiring, but in their basic contour of wiring, and genes that are expressed in both sets of neural circuits in very distinct species that are responsible for these phenomenon we're calling speech and language. I mean, what are these genes doing?

• 20:21Speaker 01

  One of the things that differ in the speech pathways of us and these song pathways of birds is some of the connections are fundamentally different than the surrounding circuits, like a direct cortical connection. From the areas that control vocalizations in the cortex, the motor neurons that control the larynx in humans, or the ser rings in birds. And so we actually made a prediction that since some of these connections differ, we're going to find genes that control neuroconnectivity and that specialize in that function that differ. And that's exactly what we found. Genes that control what we call axon guidance and formation of connections. And what was interesting, it was sort of in the opposite direction than we expected. That is, some of these genes,

• 21:06Speaker 01

  actually a number of them that control neuroconnectivity, were turned off in the speech circuit. All right. And it didn't make sense to us at first. And so we started to realize the function of these genes are to repel connections from forming. So repulsive molecules. And so when you turn them off, they allow certain connections to form that normally would have not formed. So by turning it off, you got to gain a function for speech. All right. Other genes that surprised us were genes involved in calcium buffering, neural protection, like a parvalamine or a heat shock protein. So when your brain gets hot, these proteins turn on. And we couldn't figure out for a long time, why is that the case? And then the idea popped to me one day and said,

• 21:51Speaker 01

  ah, when I heard the larynx is the fastest firing muscles in the body. All right. In order to vibrate sound and modulate sound in the way we do, you have to control, you have to move those muscles, you know, three to four to five times faster than just regular walking or running. And so when you stick electrodes in the brain areas that control learned vocalizations in these birds, and I think in humans as well, those neurons are firing at a higher rate to control these muscles. And so what is that going to do? You're going to have lots of toxicity in those neurons unless you upregulate molecules that take out the extra load

• 22:35Speaker 01

  that is needed to control the larynx. And then finally, a third set of genes that are specializing in the speech circuit are involved in neuroplasticity. Neuroplasticity, meaning allowing the brain circuits to be more flexible, so you can learn better. And why is that? I think learning how to produce speech is a more complex learning ability than, say, learning how to walk or learning how to do tricks and jumps and so forth that dogs do.

• 23:05Andrew D. Huberman?

  In terms of plasticity of speech and the ability to learn multiple languages, but even just one language, what's going on in the so-called critical period? And then the second question is, if one can already speak more than one language as a consequence of childhood learning, is it easier to acquire new languages later on?

• 23:24Speaker 01

  Actually, the entire brain is undergoing a critical period development, not just the speech pathways. And so it's easier to learn how to play a piano. It's easier to learn how to ride a bike for the first time and so forth as a young child than it is later in life. The brain can only hold so much information. And if you are undergoing rapid learning to learn, to acquire new knowledge, you also have to put memory or information in the trash, like in a computer. You only have so many gigabases of memory. Plus, also for survival, you don't want to keep forgetting things. And so the brain is designed, I believe, to undergo this critical period

• 24:08Speaker 01

  and solidify the circuits with what you learned as a child and you use that for the rest of your life. And now, the question you asked about if you learn more languages as a child, is it easier to learn as an adult? And that's a common finding out there in the literature. There are some that argue against it. But for those that support it, the idea there is you are born with a set of innate sounds you can produce, the phonemes, and you narrow that down because not all languages use all of them. And so you narrowed down the ones you use to string the phonemes together in the words that you learn, and you maintain those phonemes as an adult. And here comes along another language that's using those phonemes or in different combinations

• 24:52Speaker 01

  you're not used to, and therefore it's like starting from first principles. But if you already have them in multiple languages that you're using, then it makes it easier to use them in another third or fourth language. So it's not like your brain has maintained greater plasticity, is your brain has maintained greater ability to produce different sounds that then allows you to learn another language faster.

• 25:16Andrew D. Huberman?

  What about modes of speech and language that seem to have a depth of emotionality and meaning, but for which it departs from structured language? I think of musicians, like there are some Bob Dylan songs that to me, I understand the individual words. I like to think there's an emotion associated with it, at least I experienced some sort of emotion, and I have a guess about what he was experiencing. But if I were to just read it linearly without the music and without him singing it or somebody singing it like him, it wouldn't hold any meaning. So in other words, words that seem to have meaning but not associated with language, but somehow tap into an emotionality.

• 25:58Speaker 01

  Absolutely. So we call this difference semantic communication, communication with meaning, and affective communication, communication that has more of an emotional feeling content to it. I believe, you know, based upon imaging work and work we see in birds, when birds are communicating semantic information in their sounds, which is not too often, but it happens, versus affective communication, sing because I'm trying to attract the mate, my courtship song, or defend my territory, it's the same brain circuits, it's the same speech-like or song circuits are being used in different ways. There's several other points here, I think it's important for those listening out there

• 26:41Speaker 01

  to hear, is that when I say also this affective and semantic communication being used by similar brain circuits, it also matters the side of the brain. In birds and in humans, there's left-right dominance for learned communication, learned sound communication. So the left in us humans is more dominant for speech. But the right has a more balance for singing or processing musical sounds as opposed to processing speech. Both get used for both reasons. And so when people say your right brain is your artistic brain and your left brain is your thinking brain, this is what they're referring to.

• 27:26Speaker 01

  And so that's another distinction. The second thing that's useful to know is that all vocal learning species use their learned sounds for this emotional, affective kind of communication. But only a few of them, like humans and some parrots and dolphins, use it for the semantic kind of communication we're calling speech. And that has led a number of people to hypothesize that the evolution of spoken language of speech evolved first for singing, for this more like emotional kind of mate attraction, like the Jennifer Lopez, the Ricky Martin kind of songs and so forth. And then later on,

• 28:10Speaker 01

  it became used for abstract communication like we're doing now.

• 28:14Andrew D. Huberman?

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• 29:44Andrew D. Huberman?

  that it can call, you know, that mismatch can cue our attention.

• 29:49Speaker 01

  Yeah.

• 29:50Andrew D. Huberman?

  So how does motor circuitry that controls facial expression map onto the brain circuits that control language, speech, and even bodily and hand movements?

• 29:59Speaker 01

  You ask a great question because we both know some colleagues, like Winrick Freiwold at Rockefeller University, who study facial expression and the neurobiology behind it. Non-human primates have a lot of diversity in their facial expression like we humans do. And what we know about the neurobiology of brain regions controlling those muscles of the face is that these non-human primates and some other species that don't learn how to imitate vocalizations, they have strong connections from the cortical regions to the motor neurons that control facial expressions. And even though it's more diverse in these non-human primates, there was already a pre-existing diversity of communication, whether it's intentional or unconscious,

• 30:43Speaker 01

  through facial expression in our ancestors. And on top of that, we humans now add the voice along with those facial expressions. So it's like an email, too. You're emailing and someone says something by email. Someone can interpret that angrily or gently, and it becomes ambiguous. The facial expressions get rid of that ambiguity.

• 31:07Andrew D. Huberman?

  I'm so glad you brought that out because my next question was, and is about written language. What is the process of going from a thought to language to written word? And what's going on there? What do we know about the neural circuitry?

• 31:21Speaker 01

  What I think is going on is, to explain what you're asking, is about... I'm going to take it from the perspective of reading something. You read something on a paper. The signal from the paper goes through your eyes. It goes to the back of your brain to your visual cortical regions eventually. That visual signal then goes to your speech pathway in the motor cortex in front here in Broca's area. And you silently speak what you read in your brain without moving your muscles. And sometimes, actually, if you put electrodes, EMG electrodes on your laryngeal muscles, even on birds, you can do this. You'll see activity there while you're reading or trying to speak silently, even though no sound's coming out.

• 32:06Speaker 01

  And so your speech pathway is now speaking what you're reading. Now, to finish it off, that signal is sent to your auditory pathway so you can hear what you're speaking in your own head.

• 32:20Andrew D. Huberman?

  That's incredible.

• 32:21Speaker 01

  And this is why it's complicated. Oh, and then you got to write, right? Okay, here comes the fourth one. Now, the hand area is next to your speech pathway. It's got to take that auditory signal or even the adjacent motor signals for speaking and translate it into a visual signal on paper. So you're using at least four brain circuits, which includes the speech production and the speech perception pathways to write.

• 32:47Andrew D. Huberman?

  Stutter is a particularly interesting case. What is the current neurobiological understanding of stutter? And what's being developed in terms of treatments for stutter?

• 32:58Speaker 01

  Yeah, so we actually accidentally came across stuttering in songbirds. And we've published several papers on this to try to figure out the neurobiological basis. The first study we had was a brain area called the basal ganglia. What's the striatum part of the basal ganglia involved in coordinating movements, learning how to make movements. When it was damaged in this speech-like pathway in these birds, what we found is that they started to stutter as the brain region recovered. And unlike humans, they actually recovered after three or four months. And why is that the case? Because bird brains undergoes new neurogenesis

• 33:42Speaker 01

  in a way that human or mammal brains don't. And it was the new neurons that were coming in into the circuit, but not quite, you know, with the right proper activity was resulting in this stuttering in these birds. And after it was repaired, not exactly the old song came back as after the repair, but still it recovered a lot better. And it's now known, they call this neurogenics stuttering in humans, with damage to the basal ganglia or some type of disruption to the basal ganglia at a young age also causes stuttering in humans. And even those who are born with stuttering,

• 34:25Speaker 01

  it's often the basal ganglia that's disrupted than some other brain circuit. And we think the speech part of the basal ganglia.

• 34:33Andrew D. Huberman?

  Can adults who maintain a stutter from childhood repair that stutter?

• 34:38Speaker 01

  There are ways to overcome the stuttering through, through, you know, behavioral therapy. And I think all of the tools out there have something to do with sensory motor integration. Controlling what you hear with what you output in a thoughtful, controlled way helps reduce the stuttering.

• 35:03Andrew D. Huberman?

  Texting is a very, very interesting evolution of language. I wonder sometimes whether or not we are getting less proficient at speech because we are not required to write and think in complete sentences. What do you think's happening to language? Are we getting better at speaking, worse at speaking? And what do you think the role of things like texting and tweeting and shorthand communication, hashtagging, what's that doing to the way that our brains work?

• 35:35Speaker 01

  Texting. Actually, it has allowed for more rapid communication amongst people. It's more like a use it or lose it kind of a thing with the brain. The more you use a particular brain region or circuit, the more enhanced. It's like a muscle. The more you exercise it, the more healthier it is, the bigger it becomes and the more space it takes and the more you lose something else. So I think texting is not decreasing the speech prowess or the intellectual prowess of speech. It's converting it and using it a lot in a different way. In a way that may not be as rich in regular writing because you can only communicate so

• 36:20Speaker 01

  much nuance in short term writing. But whatever that, whatever is being done, you got people texting hours and hours and hours on the phone. So whatever your thumb circuit is going to get pretty big, actually.

• 36:36Andrew D. Huberman?

  For those listening who are interested in getting better at speaking and understanding languages, are there any tools that you recommend? Should kids learn how to read hard books and simple books? What do you recommend? Should adults learn how to do that? Everyone wants to know how to keep their brain working better, so to speak. But also, I think people want to be able to speak well and people want to be able to understand well.

• 36:59Speaker 01

  Yeah. What I've discovered personally, right, is that, so when I switched from pursuing a career in science, from a career in dance, I thought one day I would stop dancing. But I haven't because I find it fulfilling for me. And there've been periods of time, like during the pandemic, where I slowed down on dancing and so forth. And when you do that, you realize, okay, there are parts of your body where your muscle tone decreases a little bit and somewhat, or you could start to gain weight. I somehow don't gain weight that easily and I think it's related to my dance, if that's meaningful to your audience. But what I found is, in science, we like to think of a separation between movement and action and cognition.

• 37:43Speaker 01

  And there is a separation between perception and production. Cognition being perception, production being movement, right? But if the speech pathways is next to the movement pathways, what I discover is by dancing, it is helping me. Think. It is helping keeping my brain fresh. It's not just moving my muscles. I'm moving or using the circuitry in my brain to do, control a whole big body. You need a lot of brain tissue to do that. And so I argue if you want to stay cognitively intact into your old age, you better be moving. And you better be doing it consistently, whether it's dancing, walking, running,

• 38:26Speaker 01

  and also practicing speech. Oratory speech and so forth, or singing, is controlling the brain circuits that are moving your facial musculature. And it's going to keep your cognitive circuits also in tune. And I'm convinced of that from my own personal experience.

• 38:43Andrew D. Huberman?

  This has been an incredible conversation and opportunity for me to learn. I know I speak for a tremendous number of people and I just really want to say thank you for joining us today. You are incredibly busy. It's clear from your description of your science and your knowledge base that you are involved in a huge number of things. Very busy, so thank you for taking the time to speak to all of us. Thank you for the work that you're doing.

• 39:06Speaker 01

  Thank you for inviting me here to get the word out to the community of what's going on in the science world.

• 39:12Andrew D. Huberman?

  We're honored and very grateful too, Eric. Thank you.

• 39:21Speaker 02

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