Datasets:

MasaFoundation

/

huberman_lab_Dr._Erich_Jarvis_The_Neuroscience_of_Speech_Language__Music

like 0

Follow

Masa Foundation 4

A

Welcome to the Huberman Lab podcast, where we discuss science and science based tools for everyday life.

B

I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, my guest is Doctor Eric Jarvis. Doctor Jarvis is a professor at the Rockefeller University in New York City, and his laboratory studies the neurobiology of vocal learning, language, speech disorders, and, remarkably, the relationship between language, music, and movement, in particular, dance. His work spans from genomics, so, the very genes that make up our genome and the genomes of other species that speak and have language, such as songbirds and parrots, all the way up to neural circuits, that is, the connections in the brain and body that govern our ability to learn and generate specific sounds and movements coordinated with those sounds, including hand movements, and all the way up to cognition. That is, our ability to think in specific ways based on what we are saying and the way that we comprehend what other people are saying, singing and doing. As you'll soon see, I was immediately transfixed and absolutely enchanted by Doctor Jarvis's description of his work and the ways that it impacts all the various aspects of our lives. For instance, I learned from Doctor Jarvis that as we read, we are generating very low levels of motor activity in our throat. That is, we are speaking the words that we are reading at a level below the perception of sound or our own perception of those words. But if one were to put an amplifier or to measure the firing of those muscles in our vocal cords, we'd find that as we're reading information, we are actually speaking that information. And as I learned, and you'll soon learn, there's a direct link between those species in the world that have song and movement, which many of us would associate with dance and our ability to learn and generate complex language. So, for people with speech disorders like stutter, or for people who are interested in multiple language learning, bilingual, trilingual, etcetera, and frankly, for anyone who is interested in how we communicate through words, written or spoken, I'm certain today's episode is going to be an especially interesting and important one for you. Doctor Jarvis work is so pioneering that he has been awarded truly countless awards. I'm not going to take our time to list off all the various important awards that he's received, but I should point out that in addition to being a decorated professor at the Rockefeller University, he is also an investigator with the Howard Hughes Medical Institute, the so called HHMI. And for those of you that don't know HHMI, investigators are selected on an extremely competitive basis that they have to re up. That is, they have to recompete every five years. They actually receive a grade every five years. That dictates whether or not they are no longer a Howard Hughes investigator, whether or not they can advance to another five years of funding for their important research. And indeed, Howard Hughes investigators are selected not just for the rigor of their work, but for their pioneering spirit and their ability to take on high risk, high benefit work. Which is exactly the kind of work that Doctor Jarvis has been providing for decades now. Again, I think today's episode is one of the more unique and special episodes that we've had on the Huberman Lab podcast. I single it out because it really spans from the basic to the applied. And Doctor Jarvis story is an especially unique one in terms of how he arrived at becoming a neurobiologist. So, for those of you that are interested in personal journey and personal story, Doctor Jarvis is truly a special and important one. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost and consumer information about science and science related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is element. Element is an electrolyte drink with everything.

A

You need and nothing you don't.

B

That means plenty of salt, magnesium, and potassium, the so called electrolytes, and no sugar. Now, salt, magnesium, and potassium are critical to the function of all the cells in your body, in particular to the function of your nerve cells, also called neurons. In fact, in order for your neurons to function properly, all three electrolytes need to be present in the proper ratios. And we now know that even slight reductions in electrolyte concentrations or dehydration of the body can lead to deficits in cognitive and physical performance. Element contains a science backed electrolyte ratio of 1000 milligrams. That's 1 gram of sodium, 200 milligrams of potassium, and 60 milligrams of magnesium. I typically drink element first thing in the morning when I wake up in order to hydrate my body and make.

A

Sure I have enough electrolytes.

B

And while I do any kind of physical training and after physical training as well, especially if I've been sweating a lot, if you'd like to try element, you can go to drinkelement. That's lMnt.com Huberman to claim a free element sample pack with your purchase. Again, that's drinkelementlmnt.com. hubermandhe Today's episode is also brought to us by waking up. Waking up is a meditation app that includes hundreds of meditation programs, mindfulness trainings, yoga Nidra sessions, and NSDR non sleep deep rest protocols. I started using the waking up app a few years ago because even though I've been doing regular meditation since my teens and I started doing yoga Nidra about a decade ago, my dad mentioned to me that he had found an app turned out to be the waking up app, which could teach you meditations of different durations and that had a lot of different types of meditations to place the brain and body into different states and that he liked it very much.

A

So I gave the waking up app a try, and I too found it.

B

To be extremely useful because sometimes I only have a few minutes to meditate, other times I have longer to meditate. And indeed, I love the fact that I can explore different types of meditation to bring about different levels of understanding about consciousness, but also to place my brain and body into lots of different kinds of states, depending on which meditation I do. I also love that the waking up app has lots of different types of yoga Nidra sessions. For those of you who don't know, yoga Nidra is a process of lying very still but keeping an active mind. It's very different than most meditations, and there's excellent scientific data to show that yoga nidra and something similar to it called non sleep deep rest, or NSDR, can greatly restore levels of cognitive and physical energy, even with just a short ten minute session. If you'd like to try the waking up app, you can go to wakingup.com huberman and access a free 30 day trial. Again, that's wakingup.com huberman to access a free 30 day trial. And now for my discussion with Doctor Eric Jarvis.

A

Eric, so great to have you here.

C

Thank you.

A

Very interested in learning from you about speech and language. And even as I asked the question, I realized that a lot of people, including myself, probably don't fully appreciate the distinction between speech and language. Speech I think of as the motor patterns, the production of sound that has meaning, hopefully, and language, of course, come various languages and varieties of ways of communicating. But 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?

C

Yeah, well, I'm glad you invited me here, and I'm also glad to get that first question, which I consider a provocative one. The reason why I've been struggling. What is the difference with speech and language for many years? And realize why am I struggling is because there are behavioral terms, let's call them psychologically, psychology developed kind of terms that don't actually align exactly with brain function. And the question is there a distinction between speech and language? And when I look at the brain of work that other people have done, work we have done, also compared it with animal models like those who can imitate sounds like parrots and songbirds, I start to see there really isn't such a sharp distinction. So to get at what I think is going on, 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. And it turns out 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 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, siente, say, 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.

A

Fascinating, because you've raised a number of animal species early on here, and because I have basically an obsession with animals since the time I was very small, I have to ask, which animals have language? Which animals have modes of communication that are sort of like language? Yeah, you know, I've heard whale songs. I don't know what they're saying. They sound very beautiful, but they could be insulting each other, for all I know, and they very well. Maybe dolphins, birds. I mean, what do we understand about modes of communication that are like language but might not be what would classically be called language?

C

Right. So modes of communication that people would define as language more very, in a very narrow definition, they would say production of sounds. So speech and. But what about the hands to gesturing with the hands? What about a bird who is doing aerial displays in the air, communicating information through body language? Well, I'm going to go back to the brain. So what I think is going on is, for spoken language, we're using the speech pathway and all the complex algorithms there. 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. Now, we humans and a few others are the most advanced for the speech sounds or the spoken language. But a non human primate can produce gesturing in a more advanced form than they could produce sound. I'm not sure I got that across, clearly, just to say that humans are the most advanced at spoken language, but not necessarily as big a difference at gestural language compared to some other species.

A

Very clear and very interesting, and immediately prompts the question, have there been brain imaging or other sorts of studies evaluating neural activity in the context of cultures and languages, at least that I associate with a lot of hand movement, like Italian versus, I don't know, maybe you could give us some examples of cultures where language is not associated with as much overt hand movement.

C

Yes. 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 a telephone, I would have one hand here and I would be gesturing with the other hand without even you seeing me. Right. And so why is that? Some have argued, and I would agree, based upon what we've seen, is that there is 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, and that when you talk about Italian, French, English, and 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, learned 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, a number of species, have motor pathways in the brain where you can do learned 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.

A

I see. 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, and whether or not there's a bridge that we can draw between those in terms of just the basic respiration systems associated with different extreme feelings. Here's the way I'm imagining this might work. When I smell something delicious, I typically inhale more, and I might say, mmm, or something like that. Whereas if I smell something putrid, I typically turn away. I wince, and I will exhale, you know, or so kind of like turn away 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. And as I say that, I'm saying that from the orientation of a vision scientist who thinks of all visual images built up in a very basic way of a hierarchical model of the ability to see dark and light. So I could imagine this kind of primitive to more sophisticated pyramid of sound to language. Is this a crazy idea? Do we have any, do we have any evidence this is the way it works?

C

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. So for vocal communication, you have most vertebrate species vocalize, but most of them are producing innate sounds that they're born with. Producing, 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. And so this distinction between innateness and learned is more of a bigger dichotomy when it comes to vocalizations than for other behaviors in the animal kingdom. And when you go in the brain, you see it there as well. All the things you talked about, the breathing, the grunting and so forth. A lot of that is handled by the brain stem circuits right around the level of your neck and below, like a reflex kind of thing, 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, and now using that brainstem not only to produce the innate behaviors or vocal behaviors, but the learned ones.

A

As well, do we have any sense of when modern or sophisticated language evolved? Thinking back to the species that we evolved from and even within homo sapiens, has there been an evolution of language? Has there been a devolution of language?

C

Yeah, yeah, yeah, I would say. And to be able to answer that question, it does come with the caveat that I think we humans overrate ourselves when it compared to other species. And so it makes even scientists go astray in trying to hypothesize, when you especially don't find fossil evidence of language that easily out there. In terms of what happened in the past, amongst the primates which we humans belong to, we are the only ones that have this advanced vocal learning ability. Now, when you. It was assumed that it was only homo sapiens, 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, 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. 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 that our ancestors had this ability, and that we've been coming more and more advanced with it culturally and possibly genetically. But I think it's evolved sometime in the last 500,000 to a million years.

A

Incredible. Maybe we could talk a little bit more about the overlap between brain circuits that control language and speech in humans and other animals. I was weaned in the neuroscience era, where birdsong and the ability of birds to learn their tutor song was, and still is a prominent field subfield of neuroscience. And then, of course, neuroimaging of humans speaking and learning, et cetera. And this notion of a critical period, a time in which languages learned more easily than it is later in life, and the names of the different brain areas were quite different. One opens the textbooks. We hear wernickes and brocas for the humans, and you look at the birds of it, I remember HVc, robust arch. Striatum area. Hx. That's right, et cetera. But for most of our listeners, those names won't mean a whole lot. But in terms of homologies, between areas, in terms of function, what do we know? And how similar or different are the brain areas controlling speech and language in, say, a songbird and a young human child?

C

Yeah. So, going back to the 1950s or even a little earlier, Peter Mahler and others who got involved in neuroethology, the study of neurobiology of behavior in a natural way, they start to find that, behaviorally, there are these species of birds, like songbirds and parrots. 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. Their closer relatives. And then they discovered even more similarities, these critical periods that if you remove a child, 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 set birds undergo the same thing. 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. 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 Nadava, my former PhD advisor, and began to discover the area x. You talked about the robust nucleus of the archipelium. 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, 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 Broca's and laryngeal motor cortex. 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 so called complex behavior in species separated by 300 million years from a common ancestor. And not only that, we are discovering that mutations in these genes that cause speech deficits in humans, like in foxp two, 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.

A

Incredible. I have to ask, do Hummingbirds sing or DO they hum?

C

Hummingbirds hum with their wings and sing.

A

With their syrinx in a coordinated way.

C

In a coordinated way. There's some species of hummingbirds that actually will. Doug Aschwiller 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, even though it's their wings and their voice at the same time.

A

Hummingbirds are clapping to their song.

C

Clapping. 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, and I banged on the table, except they make it almost sound like their voice with their wings.

A

Incredible.

C

Yes. And they got, some of the smaller.

A

Kids would say, mind blown, right?

C

Yes.

A

Incredible.

C

Yes.

A

Incredible. I love hummingbirds, and I always feel like it's such a special thing to get in a moment to see one, because they move around so fast and they flit away so fast in these ballistic trajectories that when you get to see one stationary for a moment or even just hovering there, you feel like you're extracting so much from their little microcosm of life. But now I realize they're playing music, essentially, right?

C

Exactly. And what's amazing about hummingbirds and I'm going to say vocal learning, species in general, is that for whatever reason, they seem to evolve multiple complex traits. This idea that evolving language, spoken language in particular, comes along with a set of specializations.

A

Incredible. 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 song and learn it 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 song, different than their own species song, but never as well as they could learn their own natural, genetically linked song. Yes, 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 is the idea, yes. Is that true?

C

That is true, yes. And that's what I learned growing up as well, and talked to Peter Mahler himself about before he passed. He used to call it the innate predisposition to learn. All right, so 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, yes, if you were to take. I mean, in this case, we actually 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 caninche 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, young animal, and in one cage next to it, place its own species, adult male, 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.

A

Fantastic.

C

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

A

Incredible. 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 pigeon, 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 this 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? Is that not true?

C

I haven't studied enough myself in terms of pidgin specifically, but in terms of cultural evolution of language and hybridization between different cultures and so forth, even amongst birds with different dialects, and you bring them together. 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 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 I 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 years, 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 interesting.

A

So we've got brain circuits in songbirds and in humans that in many ways are similar, 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 phenomena we're calling speech and language. What sorts of things are those genes controlling? I could imagine they were controlling the wiring of connections between brain areas, essentially a map of a circuit, like an engineer would design a circuit for speech and language. Nature designed this for speech and language, but presumably other things, too, like the ability to connect motor patterns within the throat of muscles, within the throat and the control of the tongue. I mean, what are these genes doing?

C

You're pretty good. Yeah, you've made some very good guesses there. That makes sense. So, yes, 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 to the motor neurons that control the larynx in humans or the syrinx in birds. And so we actually made a prediction that since some of these connections differ. We're going to find genes that control neuro connectivity 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 connections. And what was interesting, it was sort of in the opposite direction that we expected. That is, some of these genes, actually a number of them, that control neuro connectivity, were turned off in the speech circuit. And it didn't make sense to us at first until 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 a gain of function for speech. Other genes that surprised us were genes involved in calcium buffering neuroprotection, like a parvavamin or 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, 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 three to four to five times faster than just regular walking or running. When you stick electrodes in the brain, areas that control, learn vocalizations in these birds, and I think in humans as well, those neurons are firing at a higher rate to control these muscles. 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 that is needed to control the larynx. And then finally, a third set of genes that are specialized 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.

A

Yeah, it's interesting as you say that, because I realize that many aspects of speech are sort of reflexive. I'm not thinking about each word I'm gonna say. They just sort of roll out of my mouth, hopefully with some forethought. We both know people that seem to speak think less. Fewer synapses between their brain and their mouth than others. Right? A lot of examples out there. And some people are very deliberate in their speech, but nonetheless, that much of speech has to be precise, and some of it less precise in terms of plasticity of speech and the ability to learn multiple languages, but even just one language, what's going on in the critical period? The so called critical period? Why is it that. So my niece speaks Spanish, she's guatemalan, speaks Spanish and English incredibly well. She's 14 years old. I've struggled with Spanish my whole life. My father's bilingual, my mother is not. I've tried to learn Spanish as an adult. It's really challenging. I'm told that had I learned it when I was eight, I would be better off. That's right. Or it would be installed within me. So the first question is, is it easier to learn multiple languages without an accent early in life? And if so, why? 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?

C

So the answer to both of those questions is yes. But to explain this, I need to let you know, 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. What I mean, easier in terms of when you start from first principles of learning something. So the very first time, if you're going to learn Chinese as a child versus the very first time you learn Chinese as an adult, or learning play piano as a child versus an adulthood. But the speech pathways, or let's say speech behavior, I think, has a stronger critical period change to it than other circuits. And what's going on there in general, why do you need a critical period to make you more stable, to make you more stubborn, so to speak? The reason, I believe, is that the brain is not. Brain can only hold so much information. And if you are undergoing rapid learning to learn, to acquire new knowledge, you also have to dump stuff, put memory or information in the trash, like in a computer. You only have so many gigabases of memory. And so therefore, 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 and solidify the circuits with what you learned as a child, and you use that for the rest of your life. And we humans stay even more plastic in our brain functions controlled by a gene called srgap two. We have an extra copy of it. That leaves our speech circuit in other brain regions, in a more immature state throughout life compared to other animals. So we're more immature. We're still juvenile like compared to other animals.

A

I knew it.

C

But we still go through the critical periods like they all do. 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 of phonemes. And you narrow that down because not all languages use all of them. And so you narrow down the ones you use to string the phonemes together in 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 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.

A

I see. Incredible.

C

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.

A

Got it. Are the hand gestures associated with sounds or with meanings of words?

C

I think the hand gestures are associated with both the sounds and the meaning of when I say sound. Like, if you are really angry and you are making a loud, screaming noise, you may make hand gestures that look like you're going to beat the wall because you're making loud sounds and loud gestures. All right, but if you want to explain something, like, come over here. What I just do now to you, for those who can't see me, I swung my hand towards you and swung it here. To me, that has a meaning to it to come here. So just like with the voice, the hand gestures are producing both qualities of sound.

A

And for people that speak multiple languages, especially those that learn those multiple languages early in development, do they switch their patterns of motor movements according to, let's say, going from Italian to Arabic or from Arabic to French in a way that matches the precision of language that they're speaking?

C

You know what? You just asked me a question I don't know the answer to. I would imagine that would make sense because of switching in terms of. Sometimes people might call this code switching, even different dialects of the same language. Could you do that with your gestures? I imagine so, but I really don't know if that's true. Or not?

A

Well, I certainly don't know from my own experience because I only speak one language.

B

I'd like to take a quick break and acknowledge one of our sponsors, athletic greens. Athletic greens, now called ag one, is a vitamin mineral probiotic drink that covers all of your foundational nutritional needs. I've been taking athletic greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking athletic greens, and the reason I still take athletic greens once or usually twice a day is that it gets me the probiotics that I need for gut health. Our gut is very important. It's populated by gut microbiota that communicate with the brain, the immune system and basically all the biological systems of our body to strongly impact our immediate and long term health. And those probiotics and athletic greens are optimal and vital for microbiotic health. In addition, athletic greens contains a number of adaptogens, vitamins and minerals that make sure that all of my foundational nutritional needs are met and it tastes great. If you'd like to try athletic greens, you can go to athleticgreens.com Huberman and they'll give you five free travel packs that make it really easy to mix up athletic greens while you're on the road, in the car, on the plane, etcetera. And they'll give you a year's supply of vitamin D, three k, two. Again, that's athleticgreens.com Huberman to to get the five free travel packs and the year's supply of vitamin D, three k.

A

Two to go a little bit into the abstract, but not too far. 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? Here's what I mean. Poetry. I think of musicians like there's 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.

C

Yep, absolutely. So we call this difference semantic communication. Communication with meaning and effective communication. Communication that has more of an emotional feeling content to it, but not with the semantics. And the two can be mixed up, like with singing words that have meaning but also have this effective emotional. You just love the sound of the singer that you're hearing. And initially, psychologists, scientists in general, thought that these were going to be controlled by different brain circuits. And it is the case there are emotional brain centers in the hypothalamus, in the cingulate cortex, and so forth that do give tone to the sounds. But I believe, you know, based upon imaging work and work we see in birds, when, when birds are communicating semantic information in their sounds, which is not too often, but it happens, versus effective communication. Sing because I'm trying to attract the mate my courtship song or defend my territory. It's the same brain circuits, the same speech like or song circuits are being used in different ways.

A

A friend of mine who's also a therapist said to me, you know, it's possible to say I love you with intense hatred and to say I hate you with intense love, and reminding me that it's possible to hear both of those statements in either way. So I guess it's not just limited to song or poetry. It also, there's something about the intention and the emotional context in which something's spoken that can heavily shape the way that we interpret what we hear.

C

That's right. And I consider all of that actually meaning, even though I defined it as people commonly do, semantic and effective communication. Effective communication to say I hate you but meant love, right, does have emotional meaning to it. And so one's more like an object kind of meaning or an abstract kind of meaning. There's several other points here. I think it's important for those listening out there to hear is that when I say also this effective 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. 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, effective 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 calling speech. And. 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 made attraction like the Jennifer Lopez, the Ricky Martin kind of songs and so forth. And then later on, it became used for abstract communication like we're doing now.

A

How interesting. Well, that's a perfect segue for me to be able to ask you about your background and motor control, not only of the hands, but of the body. So you have a number of important distinctions to your name, but one of them is that you were a member of the Alvin Ailey Dance School of Dance.

C

That's right.

A

So you're an accomplished and quite able dancer. Right. Tell us a little bit about your background in the world of dance and as how it informs your interest in neuroscience. Excuse me. And perhaps even how it relates specifically to your work on speech and language.

C

Yes. Well, it's interesting. And this kind of history even goes before my time. So in my family, my mother and father's side, they both went to the high school of music and Art here in New York City. And particularly my mother's family, going back multiple generations, they were singers. And I even did my family genealogy and found out I not only we have some relationships to some well known singers, distant relationships like felonious monk, but going back to the plantations in North Carolina and so forth, my ancestors were singers in the church, for the towns and so forth. And this somehow got passed on multiple generations to my family. And I thought I was going to grow up and be a famous singer, right? And me and my brothers and sister formed a band when we were kids and so forth. But it turned out that I didn't inherit the singing talents of some of my other family members, even though it was okay, but not like my brother, not like my mother or my aunts and my cousin puta Fey, who is now a talented native american singer, that then influenced me to do other things. And I started competing in dance contests. Actually, this is around the time of Saturday Night fever, and as a teenager, and I started winning dance contests. And I thought, oh, I can dance. And I auditioned for the high school of performing Arts, and I got in here in New York City and got into ballet. Dance and got in. Right. And thought, if I learn ballet, I can learn everything else. It was that idea. If you learn something classical, it can teach you for everything else. And I was. Yeah. At Alvin Ailey dance school, Joffrey Belli dance School. And at the end of my senior concert, I had this opportunity to audition for the Alvin Ailey dance company. And I had an opportunity to go to college. And I also fell in love with another passion that my father had, which was science. And so I liked science in high school. And I found an overlap also between the arts and sciences. Both required creativity, hard work, discipline, new discovery. Both weren't boring to me. And the one decision I made at that senior dance concert was when talking to the Alvin Ailey recruiter and thinking about it, I have to make a decision. And I thought something my mother taught me because she was growing up in the 1960s cultural revolution, do something that has a positive impact on society. And I thought, I can do that better as a dancer than a scientist. So now jump. I get into college, undergraduate school. I major in molecular biology and mathematics. I decide I want to be a biologist. Got into graduate school, wanted to study the brain at, you know, at the Rockefeller University. So I went from Hunter College to Rockefeller University. And so now I got to the brain, and I. And why did I choose the brain is because it controls dancing. But I didn't, there wasn't anybody studying dancing, and I wanted to study the brain, something that it does that's really interesting and complex. And I thought, ah, language is what it does. You couldn't study that in mice. You couldn't study in nonhuman primates. But these birds do this wonderful thing that Fernando nottebon was studying at Rockefeller. And so that's what got me into the birds and. And then jumping. Now, 15 years later. Yeah, that's right. Even after I'm into now having my own lab, studying vocal learning in these birds as a model for language in humans, it turns out that Ani Patel and others have discovered that only vocal learning species can learn how to dance.

A

Is that right?

C

That's right, yes.

A

So I've seen these. I'm just scrolling through the files here. In my mind, I think about every once in a while, someone will. I love parrots. Every once in a while, someone will send me one of these little Instagram or Twitter videos of a parrot doing what looks to me like dance. Typically, it's a cockatoo.

C

That's right.

A

Right.

C

That's right.

A

Even foot stomping to the sound.

C

Famous one called snowball out there. But there are many snowballs out there.

A

All the dancing birds are named snowball. That's an interesting tactic. So only animals with language dance.

C

Yeah. Vocal learning, in particular, the ability to imitate sounds. Yes.

A

Incredible.

C

Yes. And this now is bringing my life full circle. Right. And so when that was discovered in 2009, at that same time in my lab at Duke, we discovered that vocal learning brain pathways in songbirds as well as in humans and parrots. Right. Like snowball are embedded within circuits that control learning how to move. And that led us to a theory called the brain pathway, or motor theory of vocal learning origin, where the brain pathways for vocal learning and speech evolved by a whole duplication of the surrounding motor circuits involving learning how to move. Now, how does that explain dance? Right. Well, when snowball, the cockatoos are dancing, they're using the brain regions around their speech like circuits to do this dancing behavior. And so what's going on there, what we hypothesize and now like to test is that when this, when speech evolves in humans and the equivalent behavior in parrots and songbirds, it required a very tight integration in the brain regions that can hear sound, with the brain regions that control your muscles from moving your larynx and tongue and so forth, for producing sound. And that tight auditory motor integration, we argue, then, contaminated the surrounding brain regions. And that contamination of the surrounding brain regions now allows us, humans in particular and parrots, to coordinate our muscle movements of the rest of the body with sound in the same way we do for speech sounds. So we're speaking with our bodies when we dance.

A

Incredible. And I have to say that as poor as I am at speaking multiple languages, I'm even worse at dancing.

C

But I guarantee you're better than a monkey.

A

But not snowball the cockatoo.

C

Maybe not snowball. On YouTube, we have a video where there's some scientists dancing with snowball, and you'll see snowballs doing better than some of the scientists.

A

Okay, well, as long as I'm not the worst of all scientists at dancing, there's always neuroplasticity. May it save me someday. You said something incredible that I completely believe, even though I have minimum to, let's just say minimum dancing ability. Okay. I can get by at a party or wedding without complete embarrassment, but I don't have any structured training, so the body clearly can communicate with movement. As a trained dancer and knowing other trained dancers, I always think of dance and bodily movement and communication through bodily movement as a form of wordlessness, like a state of wordlessness. In fact, the few times when I think that maybe I'm actually dancing modestly, well for the context that I'm in, where I see other people dancing and they seem to just be very much in the movement, it's almost like a state of non spoken language. And yet what you're telling me is that there's a direct bridge at some level between the movement of the body and language. So is there a language of the body that is distinct from the language of speech. And if so, or if not, how do those map onto one another? What does that Venn diagram look like?

C

Yeah. Yeah. So let me define first, dance in this context of vocal learning species. This is the kind of dancing that we are specialized in doing. And the vocal learning species specialize in doing is synchronizing body movements of muscles to the rhythmic beat of music. And for some reason, we like doing that. We like synchronizing to sound and doing it together as a group of people. And that kind of communication amongst ourselves is more like the effective kind of communication I mentioned earlier, unlike the semantic kind. So we humans are using our voices more for the semantic, abstract communication, but we're using learn dance for the effective emotional bonding kind of communication. It doesn't mean we can't communicate semantic information in dance, and we do it, but it's not as popular like a ballet that in the nutcracker, it is popular where they are communicating. The arabian guy comes out, which I was the arabian guy in the ballet nutcracker. That's how I remember for the Westchester Ballet company when I was a teenager. We're trying to communicate meaning, and now ballet, dance, and it can go on with a whole story and so forth, but people don't interpret that as clearly as speech. They're seeing the ballet with semantic communication, with a lot of emotional content. Whereas you go out to a club. Yeah, you're not communicating. Okay, how you feeling today? Tell me about your day and so forth, you're trying to synchronize with other people in an effective way. And I think that's because the dance brain circuit inherited the more ancient part of the speech circuit, which was for.

A

Singing, I always had the feeling that with certain forms of music, in particular opera, but any kind of music where there are some long notes sung, that at some level, there was a literal resonance created between the singer and the listener. Or I think of like, the deep voice of a Johnny cash, or where at some level, you can almost feel the voice in your own body. And in theory, that could be the vibration of the. Or the firing of the phrenic nerve controlling the diaphragm, for all I know. Is there any evidence that there's a coordination between performer and audience at the level of mind and body?

C

I'm going to say possibly, yes. And the reason why is because I just came back from a conference on the neurobiology of dance.

A

Clearly, I'm going to the wrong meetings. My colleague, vision science is so boring.

C

Yes, well, one of my colleagues Tecumseh Fitch and Jonathan Fritz, they organized a particular section on this conference in Virginia. And this is the first time I was in the room with so many neuroscientists studying the neurobiology of dance. It's a new field now in the last five years. And there was one lab where they were putting eeg electrodes on the dancers, on two different dancers partnering with each other, as well as the audience seeing the dance. And some argued, okay, if you're listening to the music as well, how are you responding? Because you're asking a question about music, and I'm giving you an answer about dance. And what they found is that the dancers, when they resonated with each other during a dance, or the audience listening to the dancers and the music, there's some resonance going on there that they score as higher resonance. Their brain activity with these wireless eeg signals are showing something different. And so that's why I say possibly yet it needs more rigorous study. And this is some stuff they publish, but it's not prime time yet, but they're trying to figure this out.

A

I love it. So at least if I can't dance well, maybe I can hear and feel what it is to dance in a certain way.

C

That's right. And this will be. Some people will think that even songs that they heard, and they can almost sing to themselves in their own head, and they know what they want it to sound like, and, you know, when it really sounds good, what it sounds like, but they can't get their voice to do it.

A

I'm raising, for those listening, I'm raising my hand. No musical ability. Others in my household have tremendous musical ability with instruments and with voice, but not me.

C

Yeah. And so this is one of my. One of my selfish goals of trying to find the genetics of why can some people sing really well and some not? Is there some genetic predisposition to that? And then can I modify my own muscles or brain circuits to sing better?

A

You're still after the sing. I guess this is what happens when siblings vary in proficiency, is that competitiveness amongst brothers and sisters never goes away.

C

I've been trying to be as good as my brother Mark and Victor for the. My entire life.

A

Watch out, Mark and Victor. He's coming for you with neuroscience to back him. Earlier, you said that you discovered that you could dance. That caught my ear. It sounds like you didn't actually have to. I'm not suggesting you didn't work hard at it, but that at the moment where you discovered it, it just sort of was a skill that you had that up until that point, you didn't target a life in the world of dance. But the fact that you, quote unquote, discovered that you could dance really well and then went to this incredible school of dance and did well tells me that perhaps there is an ability that was built up in childhood and. Or that perhaps we do all have different genetic leanings for different motor functions.

C

Yeah, well, for me, there could be both explanations. Could be possible for the first. Yeah, I grew up in a family listening to Motown songs, dancing at parties and so forth. Family parties. An african american family, basically. So I grew up dancing from a young child. But this discovery, maybe dancing even more so in terms of a talented, the genetic component, if it really exists. I don't know. You know, with my 23 andme results, you know, it says I have the genetic substitutions that are associated with, you know, high intensity athletes and fast twist muscles. And who knows? Maybe that could have something to do with me being able to synchronize my body to rhythmic sounds, maybe, maybe better than some others. It turns out that my genetics also show that I have a genetic substitute that doesn't, that makes it hard for me to sing on pitch. And so that does correlate with my, you know, even though I can sing on this pitch, especially if I hear a piano or, you know, kind of playing it. But, you know, maybe that's why my siblings, you know, who didn't have that genetic predisposition in his 23 me results can go along with the genetic component as well.

A

I'm imagining family gatherings with 23 andme data and intense arguments about it. Innate and learned ability, fun, love to be in attendant. I'm not inviting myself to your Thanksgiving dinner, by the way, but I suppose I am.

C

You're welcome, Tim.

A

Thank you. I'll bring my 23 andme data. I'd love to chat a moment about facial expression. Cause that's a form of motor pattern that I think for most people out there, um, just think about smiling and frowning. But there are, of course, you know, thousands, if not millions of micro expressions and things of that sort, many of which are subconscious. And we're. We are all familiar with the fact that when what somebody says doesn't match some specific feature of their facial expression that it can, um, call, you know, that mismatch can cue our attention, especially among people that know each other very well. Like, somebody will say, well, you said that, but your right eye twitched a little bit in a way that tells me that you didn't really mean that these kinds of things, or when, in the opposite example, when the emotionality and the content of our speech is matched to a facial expression, there's something that's just so wonderful about that, because it seems like everything's aligned.

C

Yeah.

A

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

C

You ask a great question, because we both know some colleagues, like Winrich Feivold at Rockefeller University, who study facial expression and the neurobiology behind it. And now we both share some students that were co mentoring and talk about this same question that you brought up. And what I'm learning a lot is that 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, but absent connections or weak connections to the motor neurons that control the voice. So I think our diverse facial expression, even though it's more diverse than these nonhuman primates, there was already a pre existing diversity of communication, whether it's intentional or unconscious, through facial expression in our ancestors. And on top of that, we humans now add the voice along with those facial expressions.