Essentials: Neuralink & Technologies to Enhance Human Brains | Dr. Matt MacDougall
Guests: Matt MacDougall
Full transcript · Read the full conversation in order, with its original context.
§01Transcript — part 1
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. Matthew MacDougall.
Dr. MacDougall, welcome.
Good to be here.
Just to kick things off,
as a neurosurgeon and as a neuroscientist,
can you share with us your vision of the brain as an organ as it relates to what's possible there?
Surgeons tend to view the world a little bit differently than most because they like to fix
and they like to mend. And in your case, have the potential to add things into the brain that don't
exist there already. So how do you think about and conceptualize the brain as an organ? And what
do you think is really possible with the brain that most of us don't already probably think about?
The brain really is a collection of functional modules pinned together, duct taped together in this bone box attached to your head.
And sometimes you see very interesting failure modes.
So one of the most memorable patients I ever had was very early on in my training.
I was down at UC San Diego and saw a very young guy who had just been in a car accident.
We had operated on him.
And as is so often the case in neurosurgery, we had saved his life, potentially at the cost of
quality of life. When he woke from surgery with bilateral frontal lobe damage, he had essentially
no impulse control left. And so we were called back by his 80-year-old recovery room nurse
saying, you've got to come see your patient right away. Something's wrong. And we walk in to see
him and he points at his elderly nurse and says, she won't have sex with me. And, you know, it was
apparent at that moment, his frontal lobes were gone. And that person is never going to have
reasonable human behavior again. It's one of the most tragic ways to have a brain malfunction. But,
you know, anything a brain does, anything from control of hormone levels in your body,
to vision, to sensation, to, you know, the most obvious thing, which is muscle movement of any
kind from eye movement to moving your bicep. All that comes out of the brain. All of it can go
wrong, any part of it or all of it. So yeah, working with the brain is the substance of the
brain as a surgeon, very high stakes. But once in a while, you get a chance to really help.
You get a chance to fix something that seems unfixable.
And you have Lazarus-like miracles, not too uncommonly.
So it's extremely satisfying as a career.
Could you share with us one of the more satisfying experiences or what qualifies as satisfying
in neurosurgery?
Yeah.
One of the relatively newer techniques that we do is if someone comes in with a reasonably
small tumor somewhere deep in the brain that's hard to get to, the traditional approach to taking
that out would involve cutting through a lot of good normal brain and disrupting a lot of neurons,
a lot of white matter, that, you know, kind of the wires connecting neurons.
Then the modern approach involves a two millimeter drill hole in the skull down which you can pass
a little fiber optic cannula and attach it to a laser and just heat the tumor up deep inside the
brain under direct MRI visualization in real time. So this person is in the MRI scanner,
you're taking pictures every second or so. As the tumor heats up, you can monitor the temperature
and get it exactly where you want it, where it's going to kill all those tumor cells, but not hurt
hardly any of the brain surrounding it. And so not uncommonly nowadays, we have someone come in
with a tumor that previously would have been catastrophic to operate on, and we can eliminate
that tumor with, you know, leaving a poke hole in their skin, even in cases that previously would
have considered totally inoperable, say a tumor in the brainstem or a tumor in primary motor cortex
or primary verbal areas, Broca's area, where we would have expected to either not operate or do
catastrophic damage. Those people sometimes now are coming out unscathed. In your role at Neuralink
and as a neurosurgeon in other clinical settings, surely you are using machines. It's, I think,
a very exciting time in which engineers are starting to toss up big problems and go for it.
And obviously Elon is certainly among the best, if not the best, in terms of going really big.
to the extent that you are allowed, could you share with us what the missions at Neuralink
are and what the general scope of missions are? And then if possible, share with us some of the
more specific goals. I can imagine basic goals of trying to understand the brain and augment the
brain. I could imagine clinical goals of trying to repair things in humans that are suffering in
some way. Neuralink and I think Tesla and SpaceX before it end up being these blank canvases that
people project their hopes and fears onto. And so we experience a lot of upside in this. People
assume that we have superpowers in our ability to alter the way brains work, and people have
terrifying fears of the horrible things we're going to do. Those extremes are not true.
We are making a neural implant. We have a robotic insertion device that helps place
tiny electrodes, smaller than the size of a human hair, all throughout a small region of the brain.
In the first indication that we're aiming at, we are hoping to implant a series of these electrodes
into the brains of people that have had a bad spinal cord injury. So people that are essentially
quadriplegic. They have perfect brains, but they can't use them to move their body. They can't
move their arms or legs. And so this, you know, pristine motor cortex up in their brain is
completely capable of operating a human body. It's just not wired properly any longer to a human's
arms or legs. And so our goal is to place this implant into a motor cortex and have that person
be able to then control a computer. So a mouse and a keyboard, as if they had their hands on a mouse
and a keyboard, even though they aren't moving their hands. Their motor intentions are coming
directly out of the brain into the device. And so they're able to regain their digital freedom
and connect with the world through the internet. Why use robotics to insert these chips?
These electrodes are so tiny and the blood vessels on the surface of the brain so numerous
and so densely packed that a human physically can't do this. A human hand is not steady enough
to grab this couple micron width loop at the end of our electrode thread and place it accurately,
blindly, by the way, into the cortical surface accurately enough at the right depth to get
through all the cortical layers that we want to reach. I would love if human surgeons were
essential to this process, but very soon humans run out of motor skills sufficient to do this job.
And so we are required, in this case, to lean on robots to do this incredibly precise, incredibly fast, incredibly numerous placement of electrodes into the right area of the brain.
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So in some ways, Neuralink is pioneering the development of robotic surgeons as much as it's pioneering the exploration and augmentation and treatment of human brain conditions.
Right. And as the device exists currently, as we're submitting it to the FDA, it is only for the placement of the electrodes.
the robot's part of the surgery. I or another neurosurgeon still needs to do the more crude
part of opening the skin and skull and presenting the robot a pristine brain surface to sew
electrodes into. Broadly speaking, the mission of Neuralink is to reduce human suffering,
at least in the near term. There's hope that eventually there's a use here that makes sense
for a brain interface to bring AI as a tool embedded in the brain that a human can use to
augment their capabilities. I think that's pretty far down the road for us, but definitely on a
desired roadmap. In the near term, we really are focused on people with terrible medical problems
that have no options right now. So to just give us a bit fuller picture of this, you were talking
about a patient who can't move their limbs because they have spinal cord damage. The motor cortex
that controls movement is in theory fine. Make a small hole in the skull and through that hole,
a robot is going to place electrodes, obviously motor cortex, but then where, how? Is the idea
that you're going to play a concert from different locations, you're going to hit all the keys on the
piano in different combinations. I still don't understand how the signals are going to get out
of motor cortex, past the lesion and out to the limbs because the lesion hasn't been dealt with
at all in this scenario. So just to clarify there, I should emphasize we're not in the immediate
future talking about reconnecting the brain to the patient's own limbs. That's on the roadmap,
but it's way down the roadmap a few years. What we're talking about in the immediate future is
having the person be able to control electronic devices around them with their motor intentions
alone, right? So prosthetic hand and arm or just mouse and keys on a... Mouse and keys on a
keyboard for starters. So you wouldn't see anything in the world move. As they have an intention,
the patient might imagine, say, flexing their fist or moving their wrist. And what would happen
on the screen is the mouse would move down and left and click on an icon and bring up their word
processor. And then a keyboard at the bottom of the screen would allow them to select letters in
sequence and they could type. So we're using smarter algorithms to decode the motor intentions
out of the brain. We have been able to do this in monkeys really well. So we have a small army
of monkeys playing video games for smoothie rewards. And they do really well. We actually
have the world record of bit rate of information coming out of a monkey's brain to intelligently
control a cursor on a screen. We're doing that better than anyone else. Would you be willing,
or are you willing, if allowed, to have these electrodes implanted into your motor cortex?
Yeah, absolutely. I would be excited to do that. I think for the first iteration of the device,
it wouldn't be very useful because I can still move my limbs. And our first outputs from this
are things that I can do just as easily with my hands, right? Moving a mouse, typing in a keyboard,
We are necessarily making this device as a medical device for people with bad medical problems and no good options.
It wouldn't really make sense for an able-bodied person to get one in the near term.
As the technology develops and we make devices specifically designed to perform functions that can't be done even by an able-bodied person,
say eventually refine the technique to get to the point where you can type faster with your mind
and one of these devices than you can with text to speech or speech to text and your fingers.
That's a use case that makes sense for someone like me to get it. It doesn't really make sense
for me to get one when it allows me to use a mouse slightly worse than I can with my hand
currently. That said, the safety of the device, I would absolutely vouch for from the hundreds of
surgeries that I've personally done with this. I think it's much safer than many of the industry
standard FDA-approved surgeries that I routinely do on patients that no one even thinks twice about
their standard of care. Neuralink has already reached, in my mind, a safety threshold that is
far beyond a commonly accepted safety threshold. Along the lines of augmenting one's biological
function or functions in the world, I think now's the appropriate time to talk about the small lump
present in the top of your hand. For those listening, not watching, there's a small lump
between Dr. MacDougall's forefinger and thumb or index finger and thumb placed on skin on the top
of his hand. You've had this for some years now because we've known each other for, gosh, probably
seven years now or so. And you've always had it in the time that I've known you. What is that lump
and why did you put it in there? Yeah. So it's a small writable RFID tag. So it's just a very
small implantable chip that wireless devices can temporarily power. If you approach an antenna,
They can power and send a small amount of data back and forth.
Most phones have the capability of reading and writing to this chip.
For years, it let me into my house.
It unlocked a deadbolt on my front door.
For some years, it unlocked the doors at Neuralink and let me through the various locked doors inside the building.
What other sorts of things could one put into these RFIDs in theory?
and how long can they stay in there before you need to take them out and recharge them or replace
them? Well, these are passive. They're coated in biocompatible glass. And as an extra, I'm a
rock climber. And so I was worried about that glass shattering during rock climbing. I additionally
coated them in another ring of silicone before implanting that. So it's pretty safe. They're
passive. There's no battery. There's no active electronics in them. So they could last the rest
of my life. I don't think I'd ever have to remove it for any reason. You know, at some point,
the technology is always improving, so I might remove it and upgrade it. Already, there's, you
know, 10x more storage versions available that could be a drop-in replacement for this if I ever
remove it. It has a small niche use case, and it's an interesting proof of concept tiptoeing towards
the concept that you mentioned of, you know, you have to be willing to go through the things that
you're suggesting to your patients in order to say with a straight face that you think this is
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I'd like to go back to brain augmentation.
You've made very clear that one of the first goals for Neuralink is to get quadriplegics
walking again.
Well, again, just to be very clear, the first step is we aren't reconnecting the patient's
own muscle system to their motor cortex.
Allowing them, excuse me, agency over the movement of things in the world.
Yes.
And eventually their body.
And you're exactly right.
Yeah, eventually their body.
We would love to do that.
We've done a lot of work on developing a system for stimulating the spinal cord itself.
§02Transcript — part 2
And so that gets to the question that you asked a few minutes ago of how do you reconnect
the motor cortex to the rest of the body?
Well, if you can bypass the damaged area of the spinal cord and have an implant in the
spinal cord itself connected to an implant in the brain and have them talking to each
other, you can take the perfectly intact motor signals out of the motor cortex and send them
to the spinal cord, which most of the wiring should be intact in the spinal cord below the
level of, say, the injury caused by a car accident or motorcycle accident or gunshot wound or
whatever. And it should be possible to reconnect the brain to the body in that way. So not out of
the realm of possibility that in some small number of years that Neuralink will be able to reconnect
somebody's own body to their brain. Along the lines of augmentation, early on in some of the
public discussions about Neuralink that I overheard between Elon and various podcast hosts, etc.,
there was this idea thrown out that, for instance, that you would have some chips in your brain and
I would have some chips in my brain and you and I could just sit here looking at each other or not,
nodding or shaking our heads and essentially hear each other's thoughts. Is that possible
that we could sit here and just hear each other's thoughts? And also how would we restrict what the
other person could hear? Yeah. Well, so absolutely. I mean, think about the fact that we could do this
Right now, if you pulled out your phone and started texting me on my phone and I looked down and started texting you, we would be communicating without looking at each other or talking.
Shifting that function from a phone to an implanted device, it requires no magic advance, no leap forward.
It's technology we already know how to do.
If we, say, put a device in that allows you to control a keyboard and a mouse, which is our stated intention for our first human clinical trial.
And so texting each other with our brains is maybe an uninspiring rendition of this, but it's not very difficult to imagine the implementation of the same device in a more verbally focused area of the brain that allows you to more naturally speak the thoughts that you're thinking and have them rendered into speech that I can hear, maybe via a bone conducting implant.
So silently here, the thing that attracts a lot of us to a technology like Neuralink is that the ceiling is incredibly high.
There's no obvious reason that you can't interface with millions of neurons as this technology is refined and developed further.
So that's the kind of wide band, high bandwidth brain interface that you want to develop if you're talking about a semantic prosthetic, an AI assistant to your cognitive abilities.
you know, the more sci-fi things that we think about in the coming decades. So it's an important
caveat when you're evaluating these technologies. You really want it to be something that you can
expand off into the sci-fi. To what extent can these brain-machine interfaces learn and get
better and better and better because it's also listening to the nervous system that it's trying
to support? Right. It goes both ways. Basically what you're doing is taking a very crude software
intelligence. I would say not exactly a full-blown AI, but some well-designed software that can adapt
to changes in firing of the brain. And you're coupling it with another form of intelligence,
a human intelligence. And you're allowing the two to learn each other. So undoubtedly, the human
that has a Neuralink device will get better at using it over time. Undoubtedly, the software
that the Neuralink engineers have written
will adapt to the firing patterns
that the device is able to record
and over time focus in
on meaningful signals toward movement, right?
So if a neuron is a high firing rate
when you intend to move the mouse cursor
up and to the right,
it doesn't know that when it starts.
When you first put this in,
it's just a random series of signals
as far as the chip knows.
But you start correlating it with what the person, what you know the person wants to do as expressed in a series of games.
So you assume that, you know, that the person wants to move the mouse on the screen to the target that's shown because you tell them that's the goal.
And so you start correlating the activity that you record when they're moving toward an up and right target on a screen with that firing pattern.
and similarly for up and left, down and left, down and right.
And so you develop a model semi-intelligently in the software
for what the person is intending to do
and let the person run wild with it for a while
and they start to get better at using the model presented to them
by the software as expressed by the mouse moving
or not moving properly on the screen, right?
Imagine a scenario where you're asking somebody to play piano
but the sound that comes out of each key randomly shifts over time. Very difficult problem,
but a human brain is good enough with the aid of software to solve that problem and map well
enough to a semi-stable state that they're going to know how to use that mouse even when they,
say, turn the device off for the night, come back to it the next day. And some of the signals have
shifted. Let's talk about pigs. Elon and others there at Neuralink have shared some of the
progress that they've made in experimental animals that understandably evoke some strong
emotions in people. What was the rationale for using pigs? Well, let me say first, Neuralink is
almost entirely composed of animal loving people. If there was any possible way to help people the
way we want to help people without using animals in our research, we would do it. It's just not
known how to do that right now. And so we are completely restricted to making advances to
getting a device approval through the FDA by first showing that it's incredibly safe in animals.
As is the case for any medical advancement, essentially.
You know, I think we would probably be having a very different conversation around animal research
if we weren't, you know, we as a species, we as a culture, weren't just casually slaughtering
millions of animals to eat them every single day. And so that is a background against which
the relatively minuscule number of animals used in research. It becomes almost impossible to
understand why someone would point to that ridiculously small number of animals used in
research when the vast, vast majority of animals that humans use and end their lives are done for
food. In that context, we do animal research because we have to. There's no other way around
it. If tomorrow laws were changed and the FDA said, okay, you can do some of this early
experimentation in willing human participants, that would be a very interesting option. I think
there'd be a lot of people that would step up and say, yes, I'm willing to participate in early
stage clinical research. You already volunteered. Yeah. And I wouldn't be alone. On that note,
to whatever extent possible, I think Neuralink goes really, really far, much, much farther than
anyone I've ever heard of, any organization I've ever heard of, anything I've ever seen,
to give the animals agency in every aspect of the research.
We have just an incredible team of people looking out for the animals
and trying to design the experiments such that they're as purely opt-in as humanly possible.
No animal is ever compelled to participate in experiments beyond the surgery itself.
So if, say, on a given day, our star monkey pager doesn't want to play video games for smoothie,
no one forces them to ever. They have free and full access to food this entire time. So they
aren't hungry. They aren't thirsty. The only thing that would motivate them is if they want
a treat extra to their normal rations. There's never any deprivation. There's never any adverse
negative stimuli that pushes them to do anything. It's one of the underappreciated innovations out
of Neuralink is how far the animal care team has been able to move in the direction of humane
treatment of these guys. Why pigs? Yeah, pigs are, you know, they're actually fairly commonly
used in medical device research. More, you know, in the cardiac area, their hearts are, you know,
somewhat similar to human hearts. There's a lot of different kind of pigs that we use in different
contexts when we're trying to optimize a certain characteristic. So yeah, the pigs are, we don't
necessarily need them to be smart or task performers, although occasionally we have,
you know, trained them to walk on a treadmill when we're studying how their limbs move
for some of our spinal cord research. But we're not, you know, recording interesting,
say, cognitive data out of their minds. They're really just a biological platform with a skull
that's close enough in size and shape to humans to be a valid platform to study the safety of the
device. So again, the pigs are really just a safety platform to say the device is safe to implant.
It doesn't break down or cause any kind of toxic reaction. The monkeys are where we are really
doing our heavy lifting in terms of ensuring that we're getting good signals out of the device,
that what we expect to see in humans is validated on the functional level in monkeys first.
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What is your wish for brain machine interface
and brain augmentation?
So let's assume that the clinical stuff can be worked out,
or maybe you have a pet clinical condition
that you just are just yearning to see resolved.
That would be fine too.
But in addition to that,
you really just expand out.
Let's say we can extend your life 200 years
or we're thinking about the kind of world
that your children are going to live in
and their grandchildren will live in.
What do you think is really possible
with brain augmentation and brain machine interface?
And here, please feel no bias whatsoever
to answer in a way that reveals to us
your incredible empathy and consideration
of clinical conditions.
Because that's how you spend your days,
is fixing patients and helping their lives be better.
So if it lands in that category, great.
But for sake of fun and for sake of delight
and for sake of really getting us, the audience,
to understand what's really possible here,
please feel no shackles.
I love the idea down the road, and we're talking, you know, a 10-year, maybe 20-year time frame of humans just getting control over some of the horrible ways that their brains go wrong, right?
So I think everybody at this point has either known someone or second order, known someone, a friend of a friend who has been touched by addiction or depression, suicide, obesity.
These functions of the brain or malfunctions of the brain are what drives me.
These are the things that I want to tackle in my career.
In terms of my kids' lifetime, I'm thinking full human expansion of human cognition into AI, full immersion in the internet of your cognitive abilities.
Having no limitation for what you think as bottlenecked by needing to read the Wikipedia article first to have the data to inform your thoughts.
having communication with anyone that you want to, unrestricted by this, you know,
flapping air past meat on your face. It's a, you know, a means of communication that's
ridiculously prone to being misunderstood. It's also a tiny, narrow bottleneck of communication.
We're, you know, trying to send messages back and forth through a tiny straw, and there's no reason
that needs to necessarily be true. It's the way things have always been, but it isn't the way
things are going to be in the future. I think there's a million very sci-fi possibilities
in terms of banding human minds together to be even more potent as a multi-unit organism,
you know, as an opt-in multi-brain. You know, these are things that are so far down the road,
but I can't even directly see how they would be implemented.
But the technology we're working on
is a little crack in the door
that allows some of this stuff
to even be thought about in a realistic way.
To that point, I encourage anyone
who is excited about things like that,
especially mechanical engineers, software engineers,
robotics engineers, come to the Neuralink website
and look at the jobs we've got.
We need the brightest people on the planet
working on these, the hardest problems in the world,
in my opinion.
And so if you want to work on this stuff, come help us.
I really want to thank you, first of all,
for coming here today and taking time
out of your important schedule of seeing patients
and doing brain surgery, literally.
Happy to do it.
Time away from your family
and time away from your mission at Neuralink briefly
to share with people what you guys are doing.
And I really just want to thank you also for being you,
which is perhaps sounds like a kind of an odd thing to hear,
But I think as made apparent by the device implanted in your hand, you don't just do this for a job.
You live and breathe and embody, truly embody this stuff around the nervous system and trying to figure out how to fix it, how to make it better.
And you live and breathe it, and I know your deep love for it.
So I want to thank you for not just the brains that you put into it and the energy you put into it, but also for the heart that you put into it.
§03Transcript — part 3
Thanks for that, Andrew. I appreciate that. We just want to help people. We want to make things better.