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 opthalmology at

Stamford School of Medicine. And now for

my discussion with Dr. Eddie Chang.

Eddie, welcome.

>> Hi. Hi, Andrew.

>> Great to be here with you. Your main

focus these days is the neurobiology of

speech and language. So for those that

aren't familiar, could you please

distinguish for us speech versus

language in terms of whether or not

different brain areas control them? When

I think about language, I think about

words and just talking. If I sit down to

do a long podcast or I think about

asking you a question, I don't even

think about the words I want to say very

much. I mean, I have to think about them

a little bit. one would hope, but I

don't think about individual syllables

unless I'm trying to, you know, accent

something or it's a word that I have a

particular difficulty saying or I want

to change the cadence, etc. So, what in

the world is contained in these brain

areas? What is represented? Um, to me is

is perhaps one of the most interesting

questions and I know this lands square

in your wheelhouse.

>> Sure. Let's get into this uh Andrew

because this is one of the most exciting

stuff that's happening right now is

understanding how the brain processes

these exact questions. And speech

corresponds to the communication signal.

It corresponds to me moving my mouth and

my vocal tract to generate words. And

you're hearing these as an auditory

signal. Language is something much

broader. So it refers to what you're

extracting from the words that I'm

saying. We call that pragmatics and sort

of are you getting the gist of what I'm

saying? There's another aspect of it

that we call semantics. Do you

understand the meaning of these words

and uh the sentences? There's another

part that we call syntax which refers to

how the words are assembled in a

grammatical form. So those are all

really critical parts of language and

speech is just one form of language.

There's many other forms like sign

language, uh, reading. Those are all

important modalities for reading. Our

research really focuses on this area

that we're calling speech. Again, the

production of this audio signal, which

you can't see, but your microphones are

picking up. There are these vibrations

in the air that are created by my vocal

tract that are picked up by the

microphone in the case of this

recording, but also picked up by the

sensors in your ear. The very tiny

vibrations in your uh ear are picking

that up and translating that into

electrical activity. It's such a complex

feat. Some people would say it's the

most complex motor thing that we do as a

species is is just speaking. not you

know the extreme feats of acrobatics or

athleticism but speaking

>> well and especially when uh one observes

you know uh opera or um people who you

know freestyle rappers you know and of

course it's not just the lips it's the

tongue

>> and you've mentioned two other

structures ferinx and larynx are the

main ones that um can you tell us just

just educate us at a a superficial level

what this ferinx and larynx do

differentially because I think most

people aren't going to Okay, sure. I'll

talk primarily about the larynx here for

a second, which is that if you think

about when we're speaking, really what

we're doing is we're shaping the breath.

So, even before you get to the larynx,

you got to start with the expiration. We

fill up our lungs and then we push the

air out. That's a normal part of

breathing. What is really amazing about

speech and language is that we evolved

to take advantage of that normal

physiologic thing at a larynx. And what

the larynx does is that when you're

exhaling, it brings the vocal folds

together. Some people call them vocal

cords. They're not really cords. They're

really vocal folds. They're two pieces

of tissue that come together and a

muscle brings them together. And then

what happens is when the air comes

through the vocal folds, when they're

together, they vibrate at really high

frequencies, like 100 to 200 hertz. And

the reason why men and women generally

have different voice qualities is it has

to do with the size of the larynx and

the shape of it. Okay? So in general men

have a larger voice box or larynx and

the vibrating frequency the resonance

frequency of the vocal folds when the

air comes through them is about 100

hertz for men and about 200 for women.

So you take a breath in. As the air is

coming out, the vocal folds come

together. The air goes through. That

creates the sound of the voice that we

call voicing. It's not just your voice

characteristic. It's the energy of your

voice. It's coming from the larynx

there. It's a noise. And then it's the

source of the voice. And then what

happens is that energy that sound goes

up through the parts of the vocal tract

like the fairings into the oral cavity

which is your mouth and your tongue and

your lips. And what those things are

doing is that they're shaping this the

air in particular ways that create

consonants and vowels. That's what I

mean by shaping the breath. It just

starts with this exhalation. You

generate the voice in the larynx and

then everything above the larynx is

moving around just like the way my mouth

is doing right now to shape that air

into particular patterns that you can

hear is words immediately makes me

wonder about more um primitive or

non-learned vocalizations like crying or

laughter. Are those produced by the

language areas or do they have their own

unique neural structures?

>> We call those vocalizations. A

vocalization is basically where someone

can create a sound like a cry or a moan

that kind of sound. And it also involves

the exhalation of air. It also involves

some phonation at the level of larynx

where the vocal folds come together to

create that audible sound. But it turns

out that those are actually different

areas. So people who have injuries in

the speech and language areas oftentimes

can still moan. They can still vocalize.

And it is a different part of the brain.

I would say an area that uh even

non-human primates have that can be

specialized, you know, for vocalization.

It's a different form of communication

than than words, for example. Speaking

of storage of and ability to speak, you

are doing some amazing work and have

achieved some um pretty incredible

well-deserved recognition for your work

in bringing language out of paralyzed

people. essentially allowing people who

are locked in to a paralyzed state or

otherwise unable to articulate speech

using brain machine interface

essentially translating the neural

activity of areas of the brain that w

would produce speech into hardware

artificial non-biological tools in order

to allow paralyzed people to

communicate.

>> So there are a series of conditions um

they include things like brain stem

stroke. The brain stem is the part of

the brain that connects the cerebrum

which is the top part does our thinking

and a lot of the motor control, speech,

language, everything. And the brain stem

is what connects that to the spinal cord

and the nerves that go out to the face

and vocal tract. So if you have a stroke

there, you could be thinking all the

wild creative intelligent thoughts you

have in the mind and the cerebrum, but

you can't get them out into words or you

can't get them out to your hand to write

them down. So that's a very severe form

of paralysis called brain stem stroke.

There's another kind of conditions that

we call neurogenerative where the nerve

cells die basically or atrophy and a

condition called uh ALS. That's a very

severe form of paralysis. In its extreme

form, people essentially lose all

voluntary movement. The muscles to their

diaphragm and their lungs essentially

give out as well. They get weakness

there and then they can't breathe

anymore. In our field, these are kind of

like the most devastating things that

can happen. This condition of what we

call being locked in refers to this idea

that you can have completely intact

cognition and awareness but have no way

to express that. No voluntary movement,

no ability to speak and that is

devastating because uh psychologically

and socially you know you're completely

isolated. That's what we call locked in

syndrome and it's devastating. So we've

been studying this patterning of

electrical activity for consonants and

vowels. And essentially once we figured

out a lot of these codes for the

individual phonetic elements, part of

the lab started to focus on this very

specific question for people who have

these kind of paralysis. Could we

intercept those signals from the brain,

the cerebral cortex, as someone is

trying to say those words? And then can

we intercept them and then have them

taken out of the brain through wires to

a computer that are going to interpret

those signals and translate them into

words. So we started a clinical trial.

It's called the Bravo trial. It's still

underway. And the first participant in

the Bravo trial was a man who had been

paralyzed for 15 years. He was in a car

accident. He actually walked out of the

hospital the day after that car

accident, but the next day had a

complication related to it where he had

a very large stroke in the brain stem

and that turned out to be devastating.

He didn't wake up from that stroke for

about a week. He was in a coma for about

a week and when he woke up from that

coma, he realized that he couldn't speak

or move his arms or legs. As he told me

or communicated to us, that was

absolutely devastating. He wanted really

to die at that time.

>> Could he blink his eyes or move his

mouth in any way?

>> He could blink his eyes. He had some

limited mouth movements but couldn't

produce any intelligible speech. It was

like completely slurred and

incomprehensible. He survived this

injury. A lot of people who have that

kind of stroke just don't survive. The

way he actually communicates because he

has a little bit of residual neck

movements is that he improvised and had

his friends basically put a stick

attached to his baseball cap because he

could move his neck. He would

essentially type out letters on a

keyboard screen to get out words. In

fact, this is how he communicated was

through a device that he would

essentially peck out letters one by one

by moving his neck to control this stick

attached to his baseball cap. He hadn't

really spoken for about 15 years.

>> Oh, goodness.

>> Yeah. So, it was part of a clinical

trial. It was, you know, something that

our hospital and also the FDA, you know,

had to approve and looked at very

carefully. But given a lot of the work

that we had done, there was some basis

for for why this might work. And so we

did a surgery where we implanted

electrodes

onto these areas that control the vocal

tract, the areas that control the

larynx, the areas that control the lips

and tongue and jaw movements when we

normally speak. These are areas that

presumably may be active. That was our

hope. And he underwent a surgery, a

brain surgery. We put an electrode array

and we connected it to a port that was

sculled to uh screwed to his skull. And

the port actually goes through his

scalp. And he's lived with this now for

the last three years. So he has an

electrode array that's implanted over

the part of the brain that's important

for speech. It's connected to a port.

And then we connect a wire to that port

that translates those uh what we call

analog, you know, brain waves and

converts them into digital signals. We

put them through a machine learning or

artificial intelligence algorithm that

can pick up these very very subtle

patterns. You can't actually see them

with your eye uh in in the brain

activity and translate those into words.

And this is something that took weeks to

train the algorithm to interpret it

correctly. But what was incredible about

it was to see how he reacted. He would

be prompted to say a given word like you

know outside for example and then he

would think about it try to say it and

finally those words would appear on the

screen. And what was really amazing

about it was you could really tell that

he like got a kick out of that because

you know his body would shake in a way

and his head would shake in a way that

he would start to giggle. That was cool

to see, but then I also realized that

when he was giggling, it kind of screwed

up the next words. Decoding.

>> Is that a bug you've since uh fixed?

>> No, we haven't fixed that. It's easier

just to tell him to stop giggling. The

way this worked was we trained uh this

computer to recognize 50 words. We

started with a very small vocabulary

that's expanding as we speak. I think

that this is just a matter of time

before these vocabularies become much

much larger. But we started with a 50

set of words. We created essentially all

the possible sentences that you could

generate from those 50 words. Why that

was important was you can use those all

those possible sentences to create a

computational model computer model of

all the different word combinations to

give different sentences given those 50

words. And then you can essentially do

what we call autocorrect. It's the same

kind of thing that we do when you're

texting, for example, you get the wrong

letter in there. Your phone actually

knows, you know, because it's context

what to correct it. So because the

decoding is not 100% correct all the

time. In fact, it's far from that. It's

really helpful to have these other

features like autocorrect, the stuff

that we use routinely now with texting

that makes it correct and then updates

it. So, it's a combination of a lot of

things. It's the AI that is translating

those brain activity patterns, but it's

also things that we've learned from

speech and speech technologies that, you

know, you put all together and then all

of a sudden it starts to work. That was

the first time that someone was

paralyzed and could create words and

sentences uh that was just decoded from

the brain activity.

>> These days, we hear a lot about neural

link, Elon Musk's company. While brain

machine interface of the sort that you

do and that other laboratories do has

been going on for a long time, there's

been some press around neural link about

the promise of what brain machine

interface could do. What are your

thoughts about manipulating neural

circuitry to achieve suprahuman or

superhuman or super physiological

functions? And here we don't even have

to think about neural link in

particular. It's just but one example of

companies and people in laboratories

that are quite understandably

considering all this.

>> It's a really interesting time right

now. The science has been going on for

decades. The work that we've done in

this field that you call brain machine

interface. It's been going on for a

while and a lot of the early work was

just trying to restore things like arm

movement or having people or monkeys

control a computer cursor for example on

the screen. That's been going on for

decades. What's been really new is that

industry is now involved and some some

of this now becoming commercialized and

we're starting to see us now cross over

to this field where it's no longer just

research that we're talking about

medical products um that are designed to

be you know surgically implanted in some

cases you know there's people doing this

kind of work non-invasively as well that

don't require surgery. The specific

question that you were asking about is

an area that we call augmentation. So

can you build a device um that

essentially enhances someone's ability

beyond superan normal, super memory,

super communication speeds, beyond

speech for example, superior

uh precision athletic abilities. I think

that these are very serious kind of

questions to be asking now because as

you mentioned the pathway so far is

really to focus on these medical

applications.

I personally don't think that we've

thought enough actually about what these

kind of scenarios are going to look like

and I don't think we've thought through

all the ethical implications of what

this means for augmentation in

particular. There's part of this that is

not new at all. Humans throughout

history have been doing things to

augment our function. Coffee, nicotine,

all kinds of medications that cross over

from medical to consumer that is

everywhere. So the pursuit of

augmentation or performance or

enhancement is really not a new thing.

The questions really as they relate to

neurochnologies for example have to do

with the invasive nature. For example,

if these technologies require surgery,

for example, to do something that is not

for a medical application. Again, there

that is not exactly new territory

either. People do that routinely for

cosmetic kind of procedures for physical

appearance, not necessarily cognitive.

So, I do think that provided the

technology continues to emerge the way

that it does, that it's going to be

around the corner. And it probably is

not going to be in ways that are super

obvious. I don't think it's going to be

like can we easily memorize every fact

in the world, but in forms that are

going to be much more incremental and

maybe more subtle. In many ways, we

already have that now. Like for example,

you don't have to have a neural

interface embedded in your brain to get

information essentially access to all

information in the world. You just have

to have, you know, your iPhone. Whether

you could do it faster through uh a

brain interface, I definitely wouldn't

rule that out. But think about this that

the systems that we have already to

speak and to communicate have evolved

over, you know, thousands and millions

of years and they're supported by neural

structures that have bandwidth of

millions of neurons.

There's no technology that exists right

now that people are thinking about that

are in commercial form. sternly not even

in research labs that come anywhere

close to what has been evolved for those

natural purposes. So I'm essentially

saying two sides of this which is we're

already getting into this now. This is

not new territory. This topic of

augmentation both physical and

cognitive. We've already surpassed that.

That's part of what humans do in

general. But we are entering this area

of like enhanced cognition. um these

areas that I think the technology is

going to be the rate limiting step and

how far we can go and we have not had

the full conversations about number one

is this what we actually want is this

going to be good for society who gets

access to this technology these are all

things that are going to become real

world problems could you tell us what

you're doing in terms of merging the

brain machine interface with extraction

of speech signals from people who are

locked in like Poncho with facial

expressions

>> sure yeah I'm here with you in person.

We could have done this virtually

probably. It's pretty easy to do that.

We could have recorded this really

separate. But there is something about

being able to actually see your

expressions and to understand other

forms of communication. So, another

really important one is nonverbal the

expressions that you're making. For

example, if you have a quizzical look on

your face, if I'm saying something not

clear, that's a sign to me that I need

to rephrase it or to say it in a

different way or to slow down. Facial

expressions actually are really

important part of the way we speak. And

there's two things. It's not just the

expressions of like how you're feeling

and perceiving what I'm saying. But it's

also seeing my mouth move in your eyes.

actually see my mouth move and my jaw

move in a particular way that actually

allows you to hear those sounds better.

So having both the visual information

but also the sounds go into your brain

is going to improved intelligibilityly

also make it more natural. And the

reason why we're also very interested in

this idea of not just having text on a

screen, but essentially a fully computer

animated face like an avatar of the

person's speech movements and their

facial expressions is going to be a more

complete form of expression. Now you can

imagine right now that might just be

someone looking at a computer screen

interpreting these signals. But I think

the way things are going in the next

couple of years a lot more of our social

interactions more than even now are

going to move into this digital virtual

space. Of course most people are

thinking about what that means for most

consumers but it also has really

important implications for people who

are disabled right and whether how how

are they going to participate in that.

And so we were thinking really about for

people like Poncho and other people who

are paralyzed, what other forms of BCI

can we do in order to help improve their

ability to communicate. So one is

essentially building out more holistic

avatars, you know, things that can

essentially decode, you know,

essentially their their expressions or

the movements associated with their

mouth and jaw when they actually speak

to improve that communication. So, do

you envision a time not too long from

now where instead of tweeting out

something in text, my avatar will I'll

I'll type it out, but my avatar will

just say it. It'll be an image of my

avatar saying whatever it is I happen to

be tweeting at that moment.

>> That's what we're working on. That is

going to happen and it's going to happen

soon and there's a lot of progress in

that. And again, we're just trying to

enrich

um the the field of, you know, of

communication, expression um to make it

more normal. And we actually think that

having that kind of avatar is a way of

getting feedback to people learning how

to speak through a speech

neuroprothetic. That's the device that

we call it. It's a speech

neuroprothetic. That is going to be the

way that can help people learn how to do

it the quickest. Not necessarily like

trying to say words and having it come

on a screen, but actually have people

embody feel like it's part of themselves

or that they are directly controlling

that

>> that illustration or animation. I get a

lot of questions about stutter. What can

people with stutter do if they'd like to

relieve their stutter? Stutter is a

condition where the words can't come out

fluently. So, you have all the ideas,

you've got the language. In fact, you

know, remember we talked about this

distinction between language and speech.

Stuttering is a problem of speech,

right? So, the ideas, the meanings, the

grammar, it's all there in people's

stutter, but they can't get the words

out fluently. So that's a speech

condition and uh in particular it's a

condition that affects articulation

specifically about controlling the

production of words in this really

coordinated kind of movements that have

to happen in the vocal tract to produce

fluent speech

and um stuttering is a condition where

people have a predisposition to it. So

there's an aspect of stuttering. You are

a stutterer or you're not a stutterer.

But people who stutter don't stutter all

the time either. So you could be a

stutterer who stutters at sometimes but

not others. And really the the main link

between stuttering anxiety is that

anxiety can provoke it and make it

worse. That's certainly true, but it's

not necessarily caused by anxiety. It

can essentially trigger it or make it

worse, but it's not the cause of it, per

se. So the cause of it is still really

not clear, but it does have to do with

these kind of brain functions that we've

been talking about earlier, which is

that in order to produce normal fluent

speech, we're not even conscious of what

is going on in our mouths, in our

larynx, we're not conscious. And if we

were, we would not be able to speak

because it's too complex. It's too

precise. It's something that we have

really uh developed the abilities to do

and we do it naturally, right? It's part

of our programming and part of what we

learn inherently and you know it's just

through exposure.

So

stuttering is a is essentially a

breakdown at certain times

in that machinery being able to work in

a really coordinated way.

You can think about, you know, the

operations of these areas that are

controlling the vocal tract. Let's say

speech is like a symphony. In order for

it to come out normally, you've got to

have not just one part, the larynx, but

the lips, the jaw, they can't be doing

their own thing. They have to be very,

very precisely

activated and very, very precisely

controlled in a way to actually create

words. And so, in stuttering, there's a

breakdown of that coordination. If

somebody has a stutter, is it better to

address that early in life when there's

still neuroplasticity at is very robust?

And if so, what's the typical route for

treatment? I I have to imagine it's not

brain surgery typically. Um I'm guessing

there are speech therapists that that

people can talk to and and and they can

help them work out where they're getting

stuck in the relationship to anxiety.

>> Yeah, exactly. I mean, part of it is

about that anxiety, but a lot of it

really has to do with um therapy to sort

of like work through and think of tricks

basically sometimes to create conditions

where you can actually get the words to

come out. A lot of some forms of

stuttering are really initiation

problems. Just getting started itself is

is very hard. You want to start with

initial vowel or consonant, but it won't

emit. So a lot of the therapy is really

just focusing on like how do you create

the conditions you know for that to

happen. There's another aspect to it

that I find very interesting is that um

the feedback essentially what we hear

ourselves say. For example, every time

that I say a word I'm also hearing what

I'm saying. So that's what we call

auditory feedback. That turns out to be

very important. And sometimes when you

change that it can actually change the

amount someone stutters for better or

for worse. And it it's giving us a clue

that the brain is not just focused on

sending the commands out, but it's also

possibly interacting with the part that

is hearing the sounds. And there's

something might be going on in that

connection that that breaks down when

stuttering occurs. So there are

individuals that are stutterers, but

they don't stutter all the time. In

those instances, there's something

happening in those particular moments

where this very, very precise

coordination needs to happen in the

brain in order to get the words out

fluently.

>> Eddie, I have to say from the first time

we became friends, uh, 38 years ago,

>> something like that.

>> Something like that. To be sitting here

with you today for me is a absolute

thrill. Not just because we've been

friends for that long or that we got

reacquainted through the literally the

halls of medicine and science, but

because I really do see what you're

doing as really representing that front

absolute cutting edge of of exploration

and application. I mean, the story of

Poncho is but one of your many patients

that um has tremendous benefit from your

work and and now as a chair of a

department, you of course work alongside

individuals who are also doing

incredible work in the spinal cord etc.

So on behalf of myself and and everyone

listening, I just really want to thank

you for joining us today to share this

information, but also just for the work

you do. It's truly spectacular. So thank

you ever so much.

>> Thanks.