Bliss Chapman
Appearances
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Huge congrats. Thank you, thank you. Yeah, could not have done it without the team. And yeah, I mean, that's the other thing that I told the team as well, of just... this immense sense of optimism for the future. I mean, it's a very important moment for the company, needless to say, as well as hopefully for many others out there that we can help.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The main takeaway is that in the end, the performance have come back and it's actually gotten better than it was before. He's actually just beat the world record yet again last week. to 8.5 BPS. So, I mean, he's, he's just cranking and he's just improving. The previous one was that he said was eight. Correct. He said 8.5. Yeah. The previous world record in human was 4.6. Yeah.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So it's almost double. Yeah. And his goal is to try to get to 10, which is rough, roughly around kind of the median neural linker using a, you know, mouse with the hand. So it's, it's getting there. So, yeah. So the, the performance was regained. Yeah, better than before. So that's a story on its own of what took the BCI team to recover that performance.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It was actually mostly on kind of the signal processing. And so, as I mentioned, we were kind of looking at these spike outputs from the... our electrodes. And what happened is that four weeks into the surgery, we noticed that the threads have slowly come out of the brain.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the way in which we noticed this at first, obviously, is that, well, I think Nolan was the first to notice that his performance was degrading.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
and i think at the time we were also trying to do a bunch of different experimentation um you know different algorithms different um sort of ui ux so it was expected that there will be variability in the performance um but we did see kind of a steady decline and then also the way in which we
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
measure the health of the electrodes or whether they're in the brain or not is by measuring impedance of the electrode. So we look at kind of the interfacial, kind of the Randall circuit, they say, the capacitance and the resistance between the electrosurface and the medium.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And if that changes in some dramatic ways, we have some indication, or if you're not seeing spikes on those channels, you have some indications that something's happening there.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And what we noticed is that looking at those impedance plot and spike rate plots, and also because we have those electrodes recording along the depth, you're seeing some sort of movement that indicated that the reservoir being pulled out.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that obviously will have an implication on the model side, because if you're the number of inputs that are going into the model is changing because you have less of them, that model needs to get updated, right? And But there were still signals.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And as I mentioned, similar to how even when you place the signals on the surface of the brain or further away, like outside the skull, you still see some useful signals. What we started looking at is not just the spike occurrence through this BOSS algorithm that I mentioned, but we started looking at just the power of the frequency band that is interesting for Nolan to be able to modulate.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So once we kind of changed the algorithm for the implant to not just give you the boss output, but also these spike band power output, that helped us sort of refine the model with the new set of inputs. And that was the thing that really ultimately gave us the performance back. In terms of
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And obviously, the thing that we want, ultimately, and the thing that we are working towards is figuring out ways in which we can keep those threads intact for as long as possible so that we have many more channels going into the model. That's by far the number one priority that the team is currently embarking on to understand how to prevent that from happening.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The thing that I will say also is that As I mentioned, this is the first time ever that we're putting these threads in a human brain. And human brain, just for size reference, is 10 times that of the monkey brain or the sheep brain. And it's just a very, very different environment. It moves a lot more. It actually moved a lot more than we expected when we did Nolan's surgery. And...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It's just a very, very different environment than what we're used to. And this is why we do clinical trial. We want to uncover some of these issues and failure modes earlier than later. So in many ways, it's provided us with this enormous amount of data and information to be able to solve this. And this is something that Neuralink is extremely good at.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Once we have set of clear objective and engineering problem, we have enormous amount of talents across many, many disciplines to be able to come together and fix the problem very, very quickly.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It is. And, and I mean, I think, I mean, as a company, we're extremely vertically integrated. You know, we make these thin film arrays in our own microfab and,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
That's a whole thing that we can get into.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
This is the needle that's engaging with the loops in the thread. So they're the ones that... you know thread the feather loop um and then peel it from the silicon backing and then this is the thing that gets inserted into the tissue and then this pulls out leaving the thread and this kind of a notch or the shark tooth that we used to call uh is the thing that actually is um grasping the loop.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And then it's designed in such a way such that when you pull out, it leaves the loop. And the robot is controlling this needle. Correct. So this is actually housed in a cannula. And basically the robot has a lot of the optics that look for where the loop is. There's actually a 405 nanometer light that actually causes the polyimide to fluoresce so that you can locate the location of the loop.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So the loop lights up? Yeah, yeah, they do. It's a micron precision process.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, our robot is quite heavy, our current version of it. It's like a giant granite slab that weighs about a ton because it needs to be sensitive to vibration, environmental vibration. And then as the head is moving, at the speed that it's moving, there's a lot of kind of motion control to make sure that you can achieve that level of precision. a lot of optics that kind of zoom in on that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You know, we're working on next generation of the robot that is lighter, easier to transport. I mean, it is a feat to move the robot.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Absolutely. I mean, let alone you try to actually thread a loop in a sewing kit. I mean, this is like, we're talking like fractions of human hair. These things are, it's not visible.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, this proxy is super cool, actually. So there's a 3D printed skull from the images that is taken at Barrow. as well as this hydrogel mix, you know, sort of synthetic polymer thing that actually mimics the mechanical properties of the brain. It also has vasculature of the person. So basically what we're talking about here, and there's a lot of work that has gone into making this set proxy,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
that it's about finding the right concentration of these different synthetic polymers to get the right set of consistency for the needle dynamics as they're being inserted. But we practice this surgery with the person, you know, Nolan's basically physiology and brain many, many times prior to actually doing the surgery. So to every, every step, every step, every step. Yeah.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Like where does someone stand? Like, I mean, like what you're looking at is the picture. This is in, in, in our office of this kind of corner of the robot engineering space that we, you know, have created this like mock or space that looks exactly like what they would experience. All the staff would experience doing their actual surgery. So,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I mean, it's just kind of like any dance rehearsal where you know exactly where you're going to stand at what point. And you just practice that over and over and over again with an exact anatomy of someone that you're going to surgeries. And it got to a point where a lot of our engineers, when we created a craniectomy, they're like, oh, that looks very familiar. We've seen that before. Yeah.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, the power of the mind to visualize and where, I mean, there's a whole field that studies where muscle memory lies in cerebellum. Yeah, it's incredible.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
at the end of the day, the gold standard is to look at the tissue. What sort of trauma did you cause the tissue? And does that correlate to whatever behavioral anomalies that you may have seen? And that's the language to which we can communicate about the safety of inserting something into the brain and what type of trauma that you can cause.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So we actually have an entire department of pathology that looks at these tissue slices. There are many steps that are involved in doing this once you have studies that are launched with particular endpoints in mind. At some point, you have to euthanize the animal, and then you go through necropsy to collect the brain tissue samples.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You fix them in formalin, and you gross them, you section them, and you look at individual slices just to see what kind of reaction or lack thereof exists. That's the kind of the language to which FDA speaks and, you know, as well for us to kind of evaluate the safety of the insertion mechanism as well as the threats at various different time points, you know, both acute.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So anywhere between, you know, zero to three months to beyond three months.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Very high. I mean, it's a highly, highly regulated environment with the governing agencies that...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
scrutinize every every medical device that gets marketed and i think i think it's a good thing um you know it's good to have those high standards and we we try to hold extremely high standards um to kind of understand what sort of damage if any these uh innovative emerging technologies and new technologies that we're building are and you know so far i i we have been extremely impressed by lack of
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
immune response from these threads.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so what you're looking at is a stained tissue image. So this is a sectioned tissue slice from an animal that was implanted for seven months, so kind of a chronic time point. And you're seeing all these different colors, and each color indicates specific types of cell types. So purple and pink are astrocytes and microglia, respectively. They're types of glial cells.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the other thing that people may not be aware of is your brain is not just made up of soup of neurons and axons. There are other cells like glial cells that actually kind of is the glue and also react if there are any trauma or damage to the tissue. With the brown or the neurons? The brown are the neurons.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So what you're seeing is in this kind of macro image, you're seeing these like circle highlighted in white, the insertion sites. And when you zoom into one of those, you see the threads. And then in this particular case, I think we're seeing about the 16 wires that are going into the page.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the incredible thing here is the fact that you have the neurons that are these brown structures or brown circular or elliptical thing that are actually touching and abutting the threads. So what this is saying is that there's basically zero trauma that's caused during this insertion.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And with these neural interfaces, these micro electrodes that you insert, that is one of the most common mode of failure. So when you... insert these threads like the Utah ray, it causes neuronal death around the site because you're inserting a foreign object, right? And that kind of elicit these like immune response through microglia and astrocytes. They form this like protective layer around it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Not only are you killing the neuron cells, but you're also creating this protective layer that then basically prevents you from recording neural signals because you're getting further and further away from the neurons that you're trying to record. And that is the biggest mode of failure. And in this particular example, in that inset, it's about 50 micron with that scale bar.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The neurons just seem to be attracted to it. Yeah.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the way that these things, I mean, your tissues generally don't have these beautiful colors. This is a multiplex stain that uses these different proteins that are staining these at different colors. We use a very standard set of staining techniques with HE, EVA1, and NUEN, and GFAP. So if you go to the next image, this is also kind of illustrates the second point.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Cause you can make an argument. And initially when we saw the previous image, we said, oh, like, are the threads just floating? Like what is happening here? Like, are we actually looking at the right thing? So what we did is we did another stain and this is all done in-house.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
of this masson's uh trichrome stain which is in blue that shows these collagen layers so the blue basically like you don't want the blue around the implant threads because that means that there's some sort of scarring that's happened and what you're seeing if you look at individual threads is that you don't see any of the blue which means that there has been absolutely or very very minimal to a point where it's not detectable amount of trauma in these inserted threads
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so we think this is primarily due to the size as well as the flexibility of the threads. Also the fact that R1 is avoiding vasculature, so we're not disrupting or we're not causing damage to the vessels and not breaking any of the blood-brain barrier has basically caused the immune response to be muted.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so what you're looking at is not electrodes themselves. Those are the conductive wires. So each of those should probably be two micron in width. So what we're looking at is we're looking at the coronal slice. So we're looking at some slice of the tissue. So as you go deeper, you'll obviously have less and less of the tapering. of the thread.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But yeah, the point basically being that there's just kind of cells around the insert site, which is just an incredible thing to see. I've just never seen anything like this. How easy and safe is it to remove the implant? Yeah, so it depends on when. In the first three months or so after the surgery, there's a lot of kind of tissue modeling that's happening.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You know, similar to when you get a cut, you know, you obviously, you know, start over first couple weeks or depending on the size of the wound, scar tissue forming, right? There are these like contracted and then in the end, they turn into scab and you can scab it off. The same thing happens in the brain. And it's a very dynamic environment.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And before the scar tissue or the neomembrane or the new membrane that forms, it's quite easy to just pull them out. And there's minimal trauma that's caused during that. Once the scar tissue forms, and with Nolan as well, we believe that that's the thing that's currently anchoring the threads. So we haven't seen any more movements since then. So they're quite stable.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
it gets harder to actually completely extract the threads. So our current method for removing the device is cutting the thread, leaving the tissue intact and then unscrewing and taking the implant up. And that hole is now gonna be plugged with either another Neuralink or just with kind of a peak-based, plastic-based cap. Is it okay to leave the threads in there forever? Yeah, we think so.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
We've done studies where we left them there. And one of the biggest concerns that we had is like, do they migrate? And do they get to a point where they should not be? We haven't seen that. Again, once the scar tissue forms, they get anchored in place. And I should also say that When we say upgrades, we're not just talking in theory here. We've actually upgraded many, many times.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Most of our monkeys or non-human primates, NHP, have been upgraded. Pager, who you saw playing Mind Pong, has the latest version of the device since two years ago and is seemingly very happy and healthy and fat.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so there are a couple of different things here. So for Nolan, if we were to upgrade, what we would have to do is either cut the threads or extract the threads, depending on the situation there in terms of how they're anchored or scarred in. If you were to remove them with the dual substitute, you have an intact brain, so you can reinsert different threads with the updated implant package.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There are a couple of different ways other ways that we're thinking about the future of what the upgradable system looks like. One is, At the moment, we currently remove the dura, this kind of thick layer that protects the brain. But that actually is the thing that actually proliferates the scar tissue formation.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So typically, the general good rule of thumb is you want to leave the nature as is and not disrupt it as much. So we're looking at ways to insert the threads through the dura, which comes with different set of challenges, such as You know, it's a pretty thick layer. So how do you actually penetrate that without breaking the needle?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So we're looking at different needle design for that, as well as the kind of the loop engagement. The other biggest challenges are it's quite opaque optically with white light illumination. So how do you avoid still this biggest advantage that we have of avoiding vasculature? How do you image through that? How do you actually still mediate that?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So there are other imaging techniques that we're looking at to enable that. But our hypothesis is that, and based on some of the early evidence that we have, doing through the dura insertion will cause minimal scarring that causes them to be much easier to extract over time.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the other thing that we're also looking at, this is going to be a fundamental change in the implant architecture is at the moment, it's a monolithic single implant that comes with a thread that's bonded together.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So you can't actually separate the thing out, but you can imagine having two-part implant, you know, bottom part that is the thread that are inserted that has the chips and maybe a radio and some power source. And then you have another implant that has more of the computational heavy load and the bigger battery.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And then one can be under the dura, one can be above the dura, like, you know, being the plug for the skull. They can talk to each other, but the thing that you want to upgrade, the computer and not the threads, if you want to upgrade that, you just go in there, you know, remove the screws and then put in the next version. And, you know, you're off the, you know, it's a very, very easy surgery too.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Like you do a skin incision, slip this in, screw, probably be able to do this in 10 minutes.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, that is a priority. So for next versions of the implant, the key metrics that we're looking to improve are number of channels, just recording from more and more neurons. We have a pathway to actually go from currently 1,000 to hopefully 3,000, if not 6,000 by end of this year. And then end of next year, we want to get to even more, 16,000. There's a couple of limitations to that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
One is obviously being able to photolithographically print those wires. As I mentioned, it's two micron in width and spacing. Obviously, there are chips that are much more advanced than those types of resolution, and we have some of the tools that we have brought in-house to be able to do that. So traces will be narrower just so that you have to have more of the wires coming into the chip.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Chips also cannot linearly consume more energy as you have more and more channels. So there's a lot of innovations in the circuit architecture as well as the circuit design topology to make them lower power. You need to also think about if you have all of these spikes, how do you send that off to the end application?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So you need to think about bandwidth limitation there and potentially innovations in signal processing. Physically, one of the biggest challenges is gonna be the interface. It's always the interface that breaks. Bonding this thin film array to the electronics, it starts to become very, very highly dense interconnects. So how do you connectorize that?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's a lot of innovations in kind of the 3D integrations in the recent years that we can take advantage of. One of the biggest challenges that we do have is forming this hermetic barrier, right? This is an extremely harsh environment that we're in, the brain. So how do you protect it from
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
yeah, like the brain trying to kill your electronics to also your electronics leaking things that you don't want into the brain and that forming that hermetic barrier is going to be a very, very big challenge that we, you know, I think are actually well suited to tackle. How do you test that? Like what's the development environment to simulate that kind of harshness?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so this is where the accelerated life tester essentially is a brain in a vat. It literally is a vessel that is made up of... And again, for all intents and purpose for this particular types of tests, your brain is a saltwater. And you can also put some other set of chemicals like reactive oxygen species that get at kind of these interfaces and trying to cause a reaction to pull it apart.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But you could also... increase the rate at which these interfaces are aging by just increasing temperature. So every 10 degrees Celsius that you increase, you're basically accelerating time by 2x.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And there's a limit as to how much temperature you want to increase, because at some point there's some other nonlinear dynamics that causes you to have other nasty gases to form that just is not realistic in an environment. So what we do is we increase in our ALT chamber by 20 degrees Celsius that increases the aging by four times.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So essentially one day in ALT chamber is four day in calendar year. And we look at whether the implants still are intact, including the threads and- And operation and all of that. and operation and all of that. It obviously is not an exact same environment as a brain. Cause you know, brain has mechanical, you know, other more biological groups that, that attack at it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But it is a good test environment testing environment for at least the, the, the enclosure and the strength of the enclosure. And I mean, we've had implants, the current version of the implant that has been in there for, I mean, close to two and a half years, which is equivalent to a decade. And they seem to be fine.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. You have to get it in the right pH too. And then consciousness will emerge. Yeah. No. Uh, by the way, the other thing that also is interesting about our enclosure is, uh, If you look at our implant, it's not your common looking medical implant that usually is encased in a titanium can that's laser welded. We use this polymer called PCTFE, polychlorotrifluoroethylene.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
which is actually commonly used in blister packs. So when you have a pill and you try to pop the pill, there's like kind of that plastic membrane. That's what this is. No one's actually ever used this except us. And the reason we wanted to do this is because it's electromagnetically transparent. So when we talked about the electromagnetic inductive charging with titanium can.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Usually if you want to do something like that, you have to have a sapphire window and it's a very, very tough process to scale.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. We we've had, we've had, um, I mean, our monkeys have had two neural links. One in each hemisphere. And then we're also looking at, you know, potential of having one in motor cortex, one in visual cortex, and one in wherever other cortex.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
That's the goal. And, you know, we talk about at Neuralink building a generalized neural interface to the brain. And that also is strategically how we're approaching this with marketing and also with regulatory, which is, hey, look, we have the robot and the robot can access any part of the cortex.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Right now we're focused on motor cortex with current version of the N1 that's specialized for motor decoding tasks. But also at the end of the day, there's kind of a general compute available there. But typically, if you want to really get down to kind of hyper-optimizing for power and efficiency, you do need to get to some specialized function, right?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But what we're saying is that, hey, you are now used to this robotic insertion techniques, which took many, many years of showing data and in conversation with the FDA, and also internally convincing ourselves that this is safe. And
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Now, the difference is if we go to other parts of the brain, like visual cortex, which we're interested in as our second product, obviously it's a completely different environment. The cortex is laid out very, very differently. you know, it's going to be more stimulation focused rather than recording, just kind of creating visual percepts.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But in the end, we're using the same thin film array technology. We're using the same robot insertion technology. We're using the same, you know, packaging technology. Now it's more the conversation is focused around what are the differences and what are the implication of those differences in safety and efficacy.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I guess I'll start by saying that we actually have been... capable of stimulating through our dental array as well as our electronics for years. We have actually demonstrated some of that capabilities for reanimating the limb in the spinal cord. Obviously for the current EFS study, we've hardware disabled that. So that's something that we wanted to embark as a separate journey.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And obviously there are many, many different ways to write information into the brain the way in which we're doing that is through electrical you know passing electrical current and and kind of causing that to really change the local environment so that you can sort of artificially cause kind of the the neurons to depolarize in in nearby areas for for vision specifically um
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The way our visual system works, it's both well understood. I mean, anything with kind of brain, there are aspects of it that's well understood, but in the end, we don't really know anything. But the way visual system works is that you have photon hitting your eye, and in your eyes, there are these specialized cells called photoreceptor cells.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
that convert the photon energy into electrical signals. And then they get, that then gets projected to your back of your head, your visual cortex. You know, it goes through actually, you know, thalamic system called LGN that then projects it out. And then in the visual cortex there's, you know, visual area one or V1. And then there's a bunch of other higher level processing layers like V2, V3.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And there are actually kind of interesting parallels. And when you study the behaviors of these convolutional neural networks, like what the different layers of the network is detecting, you know, first they're detecting like these edges. And they're then detecting some more natural curves and then they start to detect like objects, right? Kind of similar thing happens in the brain.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And a lot of that has been inspired and also it's been kind of exciting to see some of the correlations there. But things like from there, where does cognition arise and where is color encoded? There's just not a lot of understanding, fundamental understanding there. So in terms of... kind of bringing sight back to those that are blind, there are many different forms of blindness.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's actually a million people, 1 million people in the US that are legally blind. You know, that means like certain, like score below in kind of the visual test. I think it's something like if you can see something at 20 feet distance that normal people can see at 200 feet distance, like if you're worse than that, you're legally blind.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, like to navigate your environment. And yeah, there are different forms of blindness. There are forms of blindness where there's some degeneration of your retina, these photoreceptor cells, and the rest of your visual processing that I described is intact. And for those types of individuals, you may not need to maybe stick electrodes into the visual cortex.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You can actually build retinal prosthetic devices that actually just replaces the function of that retinal cells that are degenerated. And there are many companies that are working on that. But that's a very small slice, albeit significant, still smaller slice of folks that are legally blind.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
If there's any damage along that circuitry, whether it's in the optic nerve or just the LGN circuitry or any break in that circuit, that's not going to work for you. And the source of where you need to actually cause that visual percept to happen because your biological mechanism is not doing that is by placing electrodes in the visual cortex in the back of your head.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the way in which this would work is that you would have an external camera, whether it's something as unsophisticated as a GoPro or some sort of wearable Ray-Ban type glasses that Meta's working on, that captures a scene. That scene is then converted to a set of electrical impulses or stimulation pulses that you would activate in your visual cortex through these thin film arrays. And by
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Playing some concerted orchestra of these stimulation patterns, you can create what's called phosphenes, which are these white, yellowish dots that you can also create by just pressing your eyes. You can actually create those percepts by stimulating the visual cortex.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the name of the game is really have many of those and have those percepts be, the phosphenes be as small as possible so that you can start to tell apart, like they're the individual pixels of the screen, right? So if you have many, many of those, potentially you'll be able to...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
In the long term, be able to actually get naturalistic vision, but in the short term to maybe midterm, being able to at least be able to have object detection algorithms run on your glasses, the prepop processing units, and then being able to at least see the edges of things so you don't bump into stuff.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. The thing that actually, so a couple of things, one is, you know, obviously if you're blind from birth, the way brain works, especially in the early age, Neuroplasticity is really nothing other than kind of your brain and different parts of your brain fighting for the limited territory.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And I mean, very, very quickly, you see cases where people that are, I mean, you also hear about people who are blind that have heightened sense of hearing or some other senses. And the reason for that is because that cortex that's not used just gets taken over by these different parts of the cortex. So for those types of individuals,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I mean, I guess they're going to have to now map some other parts of their senses into what they call vision, but it's going to be obviously a very, very different conscious experience. So I think that's an interesting caveat. The other thing that also is important to highlight is that we're currently limited by our biology in terms of the wavelength that we can see.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's a very, very small wavelength that is a visible light wavelength that we can see with our eyes. But when you have an external camera with this BCI system, you're not limited to that. You can have infrared, you can have UV, you can have whatever other spectrum that you want to see. And whether that gets mapped to some sort of weird conscious experience, I've no idea.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But when I, you know, oftentimes I talk to people, about the goal of Neuralink being going beyond the limits of our biology. That's sort of what I mean.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. I mean, my theory of how like visual system works also is that I mean, there's just so many things happening in the world and there's a lot of photons that are going into your eye and it's unclear exactly where some of the pre-processing steps are happening.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But I mean, I actually think that just from a fundamental perspective, there's just so much, the reality that we're in, if it's a reality, is so, there's so much data and I think humans are just unable to actually like eat enough actually to process all that information.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So there's some sort of filtering that does happen, whether that happens in the retina, whether that happens in different layers of the visual cortex, unclear. But like the analogy that I sometimes think about is, if your brain is a CCD camera and all of the information in the world is a sun,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And when you try to actually look at the sun with the CCD camera, it's just going to saturate the sensors, right? Because it's an enormous amount of energy. So what you do is you end up adding these filters, right? To just kind of narrow the information that's coming to you and being captured. And I think, you know, things like our experiences or our...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
like drugs, like propofol, that like anesthetic drug or psychedelics, what they're doing is they're kind of swapping out these filters and putting in new ones or removing older ones and kind of controlling our conscious experience.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, I think, I mean, even with our early participants, if they start to do things that I can't do, which I think is in the realm of possibility for them to be able to get, you know, 15, 20, if not like 100 BPS, right? There's nothing that fundamentally stops us from being able to achieve that type of performance. I mean, I would certainly get jealous that they can do that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. I mean, the thing that also is hard to appreciate sometimes is that He's doing these things while talking. I mean, it's multitasking, right? So it's clearly, it's obviously cognitively intensive, but similar to how when we talk, we move our hands. These things are multitasking. I mean, he's able to do that. And you won't be able to do that with other people.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
assistive technology, as far as I'm aware, you know, if you're obviously using like an eye tracking device, you know, you're very much fixated on that thing that you're trying to do. And if you're using voice control, I mean, like if you say some other stuff, yeah, you don't get to use that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But I mean, I think at some point for him, like if he wants to really achieve those high level BPS, it does require like, you know, full attention, right? And that's a separate circuitry that is a big mystery, like how attention works and you know.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, the primary goal is, you know, for our study in the first place is to achieve safety endpoints, just understand safety of this device, as well as the implantation process. And also, at the same time, understand the efficacy and the impact that it could have on the potential users lives. And
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Just because you're living with tetraplegia, it doesn't mean your situation is same as another person living with tetraplegia. It's wildly, wildly varying. And it's something that we're hoping to also understand how our technology can serve not just a very small slice of those individuals, but broader group of individuals and being able to get the feedback too.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
just really build just the best product for them. So there's obviously also goals that we have and the primary purpose of the early feasibility study is to learn from each and every participant to improve the device, improve the surgery before we embark on what's called the pivotal study that then is much larger trial that starts to look at statistical significance of your endpoints.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's required before you can then market the device. And that's how it works in the US and just generally around the world. That's the process you follow. Our goal is to really just understand from people like Nolan, P2, P3, future participants, what aspects of our device needs to improve. If it turns out that people are like, I really don't like the fact that it lasts only six hours.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I want to be able to use this computer for... you know, like 24 hours. I mean, that's, that is a, you know, user needs and user requirements, which we can only find out from just, just being able to engage with them.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
in terms of like cursor control and signal and all that kind of stuff to like life experience yeah so there's hardware changes but also just just firmware updates um so even even when we um you know had had that sort of recovery event for nolan uh you know he now has the new firmware that that he um has been updated with and
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It's similar to how your phones get updated all the time with new firmwares for security patches, whatever new functionality, UI, right? And that's something that is possible with our implant. It's not a static one-time device that can only do the thing that it said it can do. I mean, similar to Tesla, you can do over-the-air firmware updates and now you have completely new user interface.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
All this bells and whistles and improvements on everything, like the latest, right? That's, you know, when we say generalized platform, that's what we're talking about.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. And what else is there? Yeah, those are still in the realm of movement. So largely speaking, we have two programs. We have the movement program and we have the vision program. The movement program currently is focused around the digital freedom. As you can easily guess, if you can control 2D cursor in the digital space, you could move anything in the physical space.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So robotic arms, wheelchair, your environment, or even really like whether it's through the phone or just like directly to those interfaces. So like to those machines. So we're looking at ways to kind of expand those types of capability, even for Nolan. That requires, you know, conversation with the FDA and kind of showing safety data for,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
you know, if there's a robotic arm or a wheelchair that, you know, we can guarantee that they're not going to hurt themselves accidentally. Right. Um, it's very different if you're moving stuff in the, in the digital domain versus like in the physical space, you can actually, um, potentially cause harm to the participants. Um, so we're working through that right now.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Um, speech does involve different areas of the brain. Speech prosthetic is very, very fascinating. And there's actually been a lot of really, um, amazing work that's been happening in academia. You know, Sergei Stavitsky at UC Davis, Jamie Henderson, and, you know, late Krishna Shinoy at Stanford are doing just some incredible amount of work in improving speech neuroprosthetics. And
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Those are actually looking more at parts of the motor cortex that are controlling these vocal articulators and being able to even by mouthing the word or imagine speech, you can pick up those signals. The more sophisticated higher level processing areas like the Broca's area or Wernicke's area,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Those are still very, very big mystery in terms of the underlying mechanism of how all that stuff works. But yeah, I mean, I think Neuralink's eventual goal is to kind of understand those things and be able to provide a platform and tools to be able to understand that and study that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
In some ways, like, I guess this starts to kind of get into the heart problem of consciousness. Um, and, uh, I mean, on, on one hand, all of these are at some point set of electrical signals that, um, from there Maybe it in itself is giving you the cognition or the meaning, or somehow human mind is incredibly amazing storytelling machine.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So we're telling ourselves and fooling ourselves that there's some interesting meaning here, but I mean, I certainly think that PCI and, you know, really PCI at the end of the day is a set of tools that help you kind of study the underlying mechanisms and in a both like local, but also broader sense. And whether,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's some interesting patterns of electrical signal that means you're thinking this versus... And you can either learn from many, many sets of data to correlate some of that and be able to do mind reading or not. I'm not sure. I certainly would not kind of blow that out as a possibility, but... I think BCI alone probably can't do that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's probably additional set of tools and framework and also like just heart problem of consciousness at the end of the day is rooted in this philosophical question of like, what is the meaning of it all? What's the nature of our existence? Like, where's the mind emerged from this complex network? Like.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, we do really think about BCI and what we're building as a tool for understanding the mind, the brain, the only question that matters. There's actually, there actually is some biological
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
existence proof of like what it would take to kind of start to form some of these experiences that may be unique um if you actually look at every one of our brains there are two hemispheres there's a left-sided brain there's a right-sided brain and
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
i mean unless you have some other conditions you normally don't feel like left lex or right legs like you just feel like one legs right so what is happening there right um if you actually look at The two hemispheres, there's a structure that kind of connectorized the two called the corpus callosum that is supposed to have around 200 to 300 million connections or axons.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So whether that means that's the number of interface and electrodes that we need to create some sort of mind meld or from that, like whatever new conscious experience that you can experience. But I do think that there's like kind of an interesting existence proof that we all have. And that threshold is unknown at this time.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Oh yeah, these things, everything in this domain is, you know, speculation, right?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I do. First of all, there are, like, if you look at worldwide, people suffering from movement disorders and visual tephysis, I mean, that's... in the tens, if not hundreds of millions of people. So that alone, I think there's a lot of benefit and potential good that we can do with this type of technology.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And once you start to get into kind of neuro, like psychiatric application, you know, depression, anxiety, hunger, or, you know, obesity, right? Like mood control of appetite. I mean, that starts to become you know, very real to everyone.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Oh yeah. I mean that, yeah, this is even before going to that, right? I mean, there's like almost, I mean the entire world that could benefit from these types of thing. And then, yeah, like if we're talking about kind of next generation of how we interface with, you know, machines or even ourselves, in many ways, I think BCI can play a role in that.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And, you know, some of the things that I also talk about is I do think that there is a real possibility that you could see 8 billion people walking around with Neuralink.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
For me, I was always interested in understanding the purpose of things and how it was engineered to serve that purpose, whether it's organic or inorganic, like we were talking earlier about your curtain holders. They serve a clear purpose and they were engineered with that purpose in mind. And growing up, I had a lot of interest in
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
seeing things, touching things, feeling things, and trying to really understand the root of how it was designed to serve that purpose. And, you know, obviously brain is just a fascinating organ that we all carry. It's a infinitely powerful machine that has intelligence and cognition that arise from it. And, you know, we haven't even scratched the surface in terms of how all of that occurs.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But also at the same time, I think it took me a while to make that connection to really studying and building tech to understand the brain. Not until graduate school. You know, there were a couple moments, key moments in my life where some of those, I think, influenced how the trajectory of my life changed. got me to studying what I'm doing right now.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You know, one was growing up both sides of my family, my grandparents had a very severe form of Alzheimer and it's, you know, incredibly debilitating I mean, literally, you're seeing someone's whole identity and their mind just losing over time. And I just remember thinking how both the power of the mind, but also how something like that could really lose your sense of identity.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
lose the power yeah a lot of what we know about the brain actually comes from these cases where there are trauma to the brain or some parts of the brain that led someone to lose certain abilities and as a result there's some correlation and understanding of that part of the tissue being critical for that function
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And it's an incredibly fragile organ, if you think about it that way, but also it's incredibly plastic and incredibly resilient in many different ways.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Correct. Another key moment that sort of influenced how the trajectory of my life have shaped towards the current focus of my life has been during my teenage year when I came to the U.S., I didn't speak a word of English.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There was a huge language barrier and there was a lot of struggle to kind of connect with my peers around me because I didn't understand the artificial construct that we have created called language, specifically English in this case. And I remember feeling pretty isolated, not being able to connect with peers around me.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So I spent a lot of time just on my own, you know, reading books, watching movies. And I naturally sort of gravitated towards sci-fi books. I just found them really, really interesting. And also it was a great way for me to learn English.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Some of the first set of books that I picked up are Ender's Game, the whole saga by Orson Scott Card, and Neuromancer from William Gibson, and Snow Crash from Neal Stephenson. And movies like Matrix was coming out around that time point that really influenced how I think about the potential impact that technology can have for our lives in general.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So fast track to my college years, I was always fascinated by just physical stuff, building physical stuff, and especially physical things that had some sort of intelligence. And I studied electrical engineering during undergrad, and I started out my research in MEMS, so microelectromechanical systems, and really building these tiny nanostructures for temperature sensing.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And I just found that to be just incredibly rewarding and fascinating subject to just understand how you can build something miniature like that, that again, serve a function and had a purpose. And then I spent large majority of my college years basically building millimeter wave circuits for next-gen telecommunication systems for imaging.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And it was just something that I found very, very intellectually interesting, phase arrays, how the signal processing works for any modern as well as next-gen telecommunication system, wireless and wireline. EM waves or electromagnetic waves are fascinating. How do you design antennas that are most efficient in a small footprint that you have? How do you make these things energy efficient?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
That was something that just consumed my intellectual curiosity. And that journey led me to actually apply to and find myself a PhD program at UC Berkeley.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
at this consortium called the Berkeley Wireless Research Center that was precisely looking at building, at the time we called it XG, similar to 3G, 4G, 5G, but the next, next generation G system, and how you would design circuits around that to ultimately go on phones and basically any other devices that are wirelessly connected these days.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So I was just absolutely just fascinated by how that entire system works and that infrastructure works. And then also during grad school, I had sort of the fortune of having a couple of research fellowships that led me to pursue whatever project that I want.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's one of the things that I really enjoyed about my graduate school career, where you got to kind of pursue your intellectual curiosity in the domain that may not matter at the end of the day, but it's something that really... allows you the opportunity to go as deeply as you want, as well as as widely as you want.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And at the time I was actually working on this project called the Smart Band-Aid. And the idea was that when you get a wound, there's a lot of other kind of proliferation of signaling pathway that cells follow to close that wound.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And there were hypotheses that when you apply external electric field, you can actually accelerate the closing of that field by having basically electro taxing of the cells around that wound site. And specifically, not just for normal wound, there are chronic wounds that don't heal.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So we were interested in building some sort of a wearable patch that you could apply to kind of facilitate that healing process. And that was in collaboration with Professor Michelle Maharvitz, which was a great addition to kind of my thesis committee and really shaped the rest of my PhD career. So this would be the first time you interacted with biology, I suppose. Correct, correct.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I mean, there were some peripheral end application of the wireless imaging and telecommunication system that I was using for security and bioimaging, but this was... a very clear direct application to biology and biological system and understanding the constraints around that and really designing and engineering electrical solutions around it. So that was my first introduction.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's also kind of how I got introduced to Michel. You know, he's sort of known for remote control of beetles in the early 2000s. And then Around 2013, obviously kind of the holy grail when it comes to implantable system is to kind of understand how small of a thing you can make.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And a lot of that is driven by how much energy or how much power you can supply to it and how you extract data from it. So at the time at Berkeley, there was kind of this desire to kind of understand in the neural space what sort of system you can build to really miniaturize these implantable systems.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And I distinctively remember this one particular meeting where Michel came in and he's like, guys, I think I have a solution. The solution is ultrasound. Yeah. And, uh, and then he proceeded to kind of walk through why that is the case.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that, that really formed the basis for my thesis work, um, uh, called neural dust system that was looking at ways to use ultrasound as opposed to, uh, electromagnetic waves for powering as well as communication.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I guess I should step back and say the initial goal of the project was to build these tiny, about a size of a neuron, implantable system that can be parked next to a neuron, being able to record its state and being able to ping that back to the outside world for doing something useful.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And as I mentioned, the size of the implantable system is limited by how you power the thing and get the data off of it. And at the end of the day, fundamentally, if you look at a human body, we're essentially a bag of salt water with some interesting proteins and chemicals, but it's mostly salt water that's very, very well temperature regulated at 37 degrees Celsius.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And we'll get into later why that's an extremely harsh environment for any electronics to survive, as I'm sure you've experienced, or maybe not experienced, dropping a cell phone in salt water in an ocean. It will instantly kill the device, right? But anyways, just in general, electromagnetic waves don't penetrate through this environment well. And just the speed of light, it is what it is.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
We can't change it. And based on the wavelength at which you are interfacing with the device, the device just needs to be big. Like these inductors needs to be quite big. And the general good rule of thumb is that you want the wavefront to be roughly on the order of the size of the thing that you're interfacing with.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So an implantable system that is around 10 to 100 micron in dimension, in a volume, which is about the size of a neuron that you see in a human body, you would have to operate at hundreds of gigahertz, which... Number one, not only is it difficult to build electronics operating at those frequencies, but also the body just attenuates that very, very significantly.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So the interesting kind of insight of this ultrasound was the fact that ultrasound just travels a lot more effectively in the human body tissue compared to electromagnetic waves. And this is something that you encounter and I'm sure most people have encountered in their lives when you go to hospitals that are medical ultrasound sonograph.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And they go into very, very deep depth without attenuating too much of the signal. So All in all, you know, ultrasound, the fact that it travels through the body extremely well and the mechanism to which it travels to the body really well is that just the wave front is very different. It's electromagnetic waves are transverse. Whereas in ultrasound waves are compressive.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So it's just a completely different mode of, uh, wavefront propagation. Um, and as well as speed of sound is orders and orders of magnitude, less than speed of light, which means that even at 10 megahertz ultrasound wave, your wavefront ultimately is a very, very small wavelength. So if you're talking about interfacing with the 10 micron or a hundred micron type structure.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
you would have 150 micron wavefront at 10 megahertz and building electronics at those frequencies are much, much easier and they're a lot more efficient. So the basic idea kind of was born out of using ultrasound as a mechanism for powering the device and then also getting data back. So now the question is, how do you get the data back?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The mechanism to which we landed on is what's called backscattering. This is actually something that is very common and that we interface on a day-to-day basis with our RFID cards, our radio frequency ID tags, where There's actually rarely in your ID a battery inside. There's an antenna and there's some sort of coil that has your serial identification ID.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And then there's an external device called a reader that then sends a wavefront. And then you reflect back that wavefront with some sort of modulation that's unique to your ID. That's what's called backscattering fundamentally. So the tag itself actually doesn't have to consume that much energy. And that was a mechanism to which we were kind of thinking about sending the data back.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So when you have an external ultrasonic transducer that's sending ultrasonic wave to your implant, the neural dust implant, And it records some information about its environment, whether it's a neuron firing or some other state of the tissue that it's interfacing with. And then it just amplitude modulates the wavefront that comes back to the source.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Correct. So it is that initial kind of startup circuitry to get that recording, amplifying it, and then just modulating. And the mechanism to which that you can enable that is there is this specialized crystal called piezoelectric crystals that are able to convert sound energy into electrical energy and vice versa.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So you can kind of have this interplay between the ultrasonic domain and electrical domain that is the biological tissue.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I think a good starting point is going back to 1790s. I did not expect that. Where the concept of animal electricity or the fact that body's electric was first discovered by Luigi Galvani, where he had this famous experiment where he connected set of electrodes to a frog leg and ran current through it. And then it started twitching and he said, Oh my goodness, body's electric.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So fast forward many, many years to 1920s, where Hans Berger, who is a German psychiatrist, discovered EEG or electroencephalography, which is still around. There are these electrode arrays that you wear outside the skull that gives you some sort of neural recording. That was a very, very big milestone that you can record some sort of activities about the human mind.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And then in the 1940s, there were these group of scientists, Renshaw, Forbes, and Morrison that inserted these glass microelectrodes into the cortex and recorded single neurons. The fact that there's signal that are a bit more high resolution and high fidelity as you get closer to the source, let's say.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And in the 1950s, these two scientists, Hodgkin and Huxley showed up and they built this beautiful, beautiful models of the cell membrane and the ionic mechanism and had these like circuit diagram. And as someone who is an electrical engineer, it's a beautiful model that's built out of
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
these partial differential equations, talking about flow of ions and how that really leads to how neurons communicate. And they won the Nobel Prize for that 10 years later in the 1960s. So in 1969, Ed Fetz from University of Washington published this beautiful paper called Operant Conditioning of Cortical Unit Activity, where
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
He was able to record a single unit neuron from a monkey and was able to have the monkey modulate it based on its activity and reward system. So I would say this is the very, very first example, as far as I'm aware, of closed loop brain computer interface or BCI.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, number of experiments as well as set of tools to interface with the brain have just exploded. I think, and also just understanding the neural code and how some of the cortical layers and the functions are organized. So the other paper that is pretty seminal, especially in the motor decoding, was this paper in the 1980s from Georgiopoulos.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
that discovered that there's this thing called motor tuning curve. So what are motor tuning curves? It's the fact that there are neurons in the motor cortex of mammals, including humans, that have a preferential direction that causes them to fire.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So what that means is there are set of neurons that would increase their spiking activities when you're thinking about moving to the left, right, up, down. and any of those vectors. And based on that, you could start to think, well, if you can identify those essential eigenvectors, you can do a lot.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And you can actually use that information for actually decoding someone's intended movement from the cortex. So that was a very, very seminal kind of paper that showed that there is some sort of code that you can extract, especially in the motor cortex.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And if you measure the electrical signal from the brain that you could actually figure out what the intention was. Correct. Yeah, not only electrical signals, but electrical signals from the right set of neurons that give you these preferential direction.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
That answer fundamentally depends on what you want to do with it, right? There's actually an incredible amount of stuff that you can do with EEG and electrocorticograph, ECOG, which actually doesn't penetrate the cortical layer or parenchyma, but you place a set of electrodes on the surface of the brain. So the thing that I'm personally very interested in is just actually understanding
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
and being able to just really tap into the high resolution, high fidelity, understanding of the activities that are happening at the local level. And, you know, we can get into biophysics, but just to kind of step back to kind of, use analogy because analogy here can be useful. Sometimes it's a little bit difficult to think about electricity.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
At the end of the day, we're doing electrical recording that's mediated by ionic currents, movements of these charged particles, which is really, really hard for most people to think about. But turns out a lot of the activities that are happening in the brain and the frequency band with which that's happening is actually very, very similar to sound waves and our normal conversation audible range.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So the analogy that typically is used in the field is, if you have a football stadium, There's a game going on. If you stand outside the stadium, you maybe get a sense of how the game is going based on the cheers and the boos of the home crowd, whether the team is winning or not. But you have absolutely no idea what the score is.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You have absolutely no idea what individual audience or the players are talking or saying to each other, what the next play is, what the next goal is. So what you have to do is you have to drop the microphone into the stadium and then get near the source, like into the individual chatter. In this specific example, you would want to have it right next to where the huddle's happening.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So I think that's kind of a good illustration of what we're trying to do when we say, invasive or minimally invasive or implanted brain computer interfaces versus non-invasive or non-implanted brain interfaces. It's basically talking about where do you put that microphone and what can you do with that information.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so... The brain is made up of these specialized cells called neurons. There's billions of them, tens of billions. Sometimes people call it a hundred billion that are connected in this complex yet dynamic network that are constantly remodeling. They're changing their synaptic weights and that's what we typically call neuroplasticity.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the neurons are also bathed in this charged environment that is latent with many charged molecules like potassium ions, sodium ions, chlorine ions. And those actually facilitate these through ionic current communication between these different networks.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And when you look at a neuron as well, they have these membrane with a beautiful, beautiful protein structure called the voltage selective ion channels, which in my opinion is one of nature's best inventions. In many ways, if you think about what they are, they're doing the job of a modern day transistors. Transistors are nothing more at the end of the day than a voltage gated conduction channel.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And nature found a way to have that very, very early on in its evolution. And as we all know, with the transistor, you can have many, many computation and a lot of amazing things. that we have access to today. So I think it's one of those, just as a tangent, just a beautiful, beautiful invention that the nature came up with, these voltage-gated ion channels.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, there are actually, I mean, there's a lot of really, really interesting physics that are involved. And, you know, kind of going back to my work on ultrasound during grad school, there were groups and there are still groups looking at ways to cause neurons to actually... fire and action potential using ultrasound wave.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the mechanism to which that's happening is still unclear as I understand. It may just be that you're imparting some sort of thermal energy and that causes cells to depolarize in some interesting ways. But there are also these ion channels or even membranes that actually just open up its pore as they're being mechanically like shook, vibrated.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's just a lot of, you know, elements of these like move particles, which again, like that's governed by diffusion physics, right? Movements of particles. And there's also a lot of kind of interesting physics there.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Oh yeah, yeah. I mean, you can, yes, there's a lot of levels of physics that you can dive into. But yeah, in the end, you have these membranes with these voltage-gated ion channels that selectively let these charged molecules that are in the extracellular matrix in and out.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And these neurons generally have these resting potential where there's a voltage difference between inside the cell and outside the cell. And when there's some sort of... stimuli that changes the state such that they need to send information to the downstream network. You start to see these orchestration of these different molecules going in and out of these channels.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
They also open up, more of them open up once it reaches some threshold to a point where you have a depolarizing cell that sends an action potential. So it's just a very beautiful kind of orchestration of these molecules.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And what we're trying to do when we place an electrode or parking it next to a neuron is that you're trying to measure these local changes in the potential, again, mediated by the movements of the ions. And what's interesting, as I mentioned earlier, there's a lot of physics involved. And the two dominant physics for this electrical recording domain is diffusion physics and electromagnetism.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Where one dominates, where Maxwell's equation dominates versus Fick's law dominates, depends on where your electrode is. If it's close to the source, mostly electromagnetic based, when you're farther away from it, it's more diffusion based. Essentially, when you're able to park it next to it, you can listen in on those individual chatter and those local changes in the potential.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the type of signal that you get are these canonical textbook neural spiking waveform. The moment you're further away, and based on some of the studies that people have done, Christoph Koch's lab and others, once you're away from that source by roughly around 100 micron, which is about the width of a human hair, you no longer hear from that neuron.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You're no longer able to have the system sensitive enough to be able to record that particular local membrane potential change in that neuron. Just to kind of give you a sense of scale also, when you look at 100 micron voxel, so 100 micron by 100 micron by 100 micron box in a brain tissue, there's roughly around 40 neurons and whatever number of connections that they have.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So there's a lot in that volume of tissue. So the moment you're outside of that, there's just no hope that you'll be able to detect that change from that one specific neuron that you may care about. Yeah, but as you're moving about the space-
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, you want to listen to the chatter. And at the end of the day, you also want to basically let the software do the job of decoding. And just to kind of go to why ECOG and EEG work at all, right? When you have these local changes, you know, obviously it's not just this one neuron that's activating. There's many, many other networks that are activating all the time.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And you do see sort of a general change in the potential of this electrode, like this charged medium, right? And that's what you're recording when you're farther away. I mean, you still have some reference electrode that's stable in the brain that's just electroactive organ. And you're seeing some combination aggregate action potential changes. And then you can pick it up, right?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It's a much slower changing process. but there are these like canonical kind of oscillations and waves, like gamma waves, beta waves, like when you sleep, that can be detected, because there's sort of a synchronized kind of global effect of the brain that you can detect.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And I mean, the physics of this go, like, I mean, if we really want to go down that rabbit hole, like there's a lot that goes on in terms of,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
like why diffusion physics at some point dominates when you're further away from the source you know it it's just a charged medium um so similar to how when you have electromagnetic waves propagating in atmosphere or in in a charged medium like a plasma there's this weird shielding that happens that actually um further attenuates the signal um as you move away from it so yeah you see like if you do a really really deep dive on
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
kind of the signal attenuation over distance you start to see kind of one over r square in the beginning and then exponential drop off and that's the knee at which you know you go from electromagnet magnetism dominating to diffusion physics dominating
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Correct. Yeah. So once you penetrate the brain, you know, you're in the arena, so to speak. And there's a lot of neurons.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Also, most of them are silent. They don't really do much. Or their activities are, you have to hit it with just the right set of stimulus. So they're usually quiet. They're usually very quiet. There's, I mean, similar to dark energy and dark matter, there's dark neurons. What are they all doing?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
When you place these electrode, again, like within this hundred micron volume, you have 40 or so neurons. Like, why do you not see 40 neurons? Why do you see only a handful? What is happening there?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so there are three major components to the technology that we're building. One is the device, the thing that's actually recording these neural chatters. We call it N1 implant or the link. We have a surgical robot that's actually doing an implantation of these tiny, tiny wires that we call threads that are smaller than human hair.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And once everything is surgeries, you have these neural signals, these spiking neurons that are coming out of the brain, and you need to have some sort of software to decode what the users intend to do with that. So there's what's called a Neuralink application or B1 app that's doing that translation.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It's running the very, very simple machine learning model that decodes these inputs that are neural signals and then convert it to a set of outputs that allows our participant, first participant, Nolan, to be able to control a cursor. And this is done wirelessly. And this is done wirelessly. So our implant is actually a two-part.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The link has these flexible tiny wires called threads that have multiple electrodes along its length. And they're only inserted into the cortical layer, which is about three to five millimeters in a human brain. In the motor cortex region, that's where the intention for movement lies in.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And we have 64 of these threads, each thread having 16 electrodes along the span of three to four millimeters, separated by 200 microns. So you can actually record along the depth of the insertion. And based on that signal, there's custom integrated circuit or ASIC that we built that amplifies the neural signals that you're recording and then digitizing it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And then has some mechanism for detecting whether there was an interesting event that is a spiking event. and decide to send that or not send that through Bluetooth to an external device, whether it's a phone or a computer that's running this Neuralink application.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. So it does the signal processing to kind of really compress the amount of signal that you're recording. So we have a total of thousand electrodes, um, sampling at, uh, you know, just under 20 kilohertz with 10 bit each. So, uh, that's 200 megabits, um, that's coming through to the chip, uh, from thousand, uh, channel simultaneous, uh, neural recording. And that's quite a bit of data.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
and you know there is there are technology available to send that off wirelessly but being able to do that in a very very thermally constrained environment that is a brain so there has to be some amount of compression that happens to send off only the interesting data that you need which in in this particular case for motor decoding is
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
occurrence of a spike or not, and then being able to use that to decode the intended cursor movement. So the implant itself processes it, figures out whether a spike happened or not with our spike detection algorithm, and then sends it off, packages it, sends it off through Bluetooth
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
to an external device that then has the model to decode, okay, based on these spiking inputs, did Nolan wish to go up, down, left, right, or click, or right click, or whatever?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, there's an external charging device. So yeah, the second part of the implant, the threads are the ones, again, just the last... three to five millimeters are the ones that are actually penetrating the cortex. Uh, rest of it is actually most of the volume is occupied by the battery, uh, rechargeable battery. Um, and, uh, you know, it's about a size of a quarter.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Uh, you know, I actually have a device here. If you want to take a look at it, um, you know, this is the flexible thread component of it. And this is the implant. So it's about a size of a US quarter. It's about nine millimeter thick.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So basically this implant, once you have the craniectomy and the durectomy, threads are inserted and the hole that you created, this craniectomy, gets replaced with that. So basically that thing plugs that hole and you can screw in these self-drilling cranial screws to hold it in place.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And at the end of the day, once you have the skin flap over, there's only about two to three millimeters that's obviously transitioning off of the top of the implant to where the screws are. And that's the minor bump that you have.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
They are also, the threads themselves are quite strong.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And the thread themselves also has a very interesting feature at the end of it called the loop. And that's the mechanism to which the robot is able to interface and manipulate this tiny hair-like structure. And they're tiny. So what's the width of a thread? Yeah, so the width of a thread starts from 16 micron and then tapers out to about 84 micron.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So, you know, average human hair is about 80 to 100 micron in width. This thing is amazing. This thing is amazing. Yes, most of the volume is occupied by the battery, rechargeable lithium-ion cell. And the charging is done through inductive charging, which is actually very commonly used. Most cell phones have that. The biggest difference is that for us,
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Usually when you have a phone and you wanna charge it on a charging pad, you don't really care how hot it gets. Whereas for us, it matters. There's a very strict regulation and good reasons to not actually increase the surrounding tissue temperature by two degrees Celsius. So there's actually a lot of innovation that is packed into this.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
to allow charging of this implant without causing that temperature threshold to reach. And even small things like you see this charging coil and what's called a ferrite shield, right? So without that ferrite shield, what you end up having when you have resonant inductive charging is that the battery itself is a metallic can.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And you form these eddy currents from external charger, and that causes heating. And that actually contributes to inefficiency in charging. So this ferrite shield, what it does is that it actually concentrates that field line away from the battery and then around the coil that's actually wrapped around it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, there's a lot of innovation here. I would say that part of what enabled this was... just the innovations in the wearable. There's a lot of really, really powerful, tiny, low-power microcontrollers, temperature sensors or various different sensors, and power electronics. A lot of innovation really came in.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The charging coil design, how this is packaged, and how do you enable charging such that you don't really exceed that temperature limit, which is not a constraint for other devices out there.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so the current instantiation of the device has 64 threads and each thread has 16 electrodes for a total of 1,024 electrodes that are capable of both recording and stimulating. And the thread is basically this polymer insulated wire. The metal conductor is the kind of a tiramisu cake of Thai gold plat Thai. And they're very, very tiny wires, two micron in width.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So two, one millionth of a meter.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yes, you're not going to be able to see it with naked eyes.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yes, yes. That's also one element that was incredibly important for us. So each of these threads are, as I mentioned, 16 micron in width, and then they taper to 84 micron. But in thickness, they're less than 5 micron. And in thickness, it's mostly polyimide at the bottom and this metal track, and then another polyimide. So 2 micron of polyimide.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
400 nanometer of this metal stack and two micron of polyimide sandwiched together to protect it from the environment that is 37 degrees C bag of salt water.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so the material selection that we have is not, I don't think it was particularly unique. There were other labs and there are other labs that are kind of looking at similar material stack. There's kind of a fundamental question and still needs to be answered around
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
the longevity and reliability of these microelectrodes that we call, compared to some of the other more conventional neural interfaces, devices that are intracranial, so penetrating the cortex, that are more rigid, like the Utah ray. that are these four by four millimeter kind of silicon shank that have exposed recording site at the end of it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And, you know, that's been kind of the innovation from Richard Norman back in 1997. It's called the Utah Ray because, you know, he was at University of Utah.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah. Yeah, so it's a bed of needle. There's... Okay, go ahead. I'm sorry. Those are rigid shank. Rigid, yeah, you weren't kidding. And the size and the number of shanks vary anywhere from 64 to 128. At the very tip of it is an exposed electrode that actually records neural signal.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The other thing that's interesting to note is that unlike Neuralink threads that have recording electrodes that are actually exposed Iridium Oxide recording sites along the depth, this is only at a single depth. So these Utah Array spokes can be anywhere between 0.5 millimeters to 1.5 millimeter. And they also have designs that are slanted so you can have it inserted at different depth.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But that's one of the other big differences. And then, I mean, the main key difference is the fact that there's no active electronics. These are just electrodes. And then there's a bundle of a wire that you're seeing. And then that actually then exits the craniectomy that then has this port that you can connect to for any external electronic devices.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
They are working on or have the wireless telemetry device, but it still requires a through-the-skin cable. port that actually is one of the biggest failure modes for infection for the system.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, so as you mentioned, they're very, very difficult to maneuver by hand. These youth arrays that you saw earlier, they're actually inserted by a neurosurgeon actually positioning it near the site that they want, and then... there's a pneumatic hammer that actually pushes them in. So it's a pretty simple process and they're easier to maneuver.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But for these thin foam arrays, they're very, very tiny and flexible. So they're very difficult to maneuver. So that's why we built an entire robot to do that. There are other reasons for why we built the robot. And that is ultimately we want this to help millions and millions of people that can benefit from this. And there just aren't that many neurosurgeons out there.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And robots can be something that we hope can actually do large parts of the surgery. But yeah, the robot is this entire other sort of category of product that we're working on. And it's essentially this, multi-axis gantry system that has the specialized robot head that has all of the optics and this kind of a needle retracting mechanism that maneuvers these threads
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
via this loop structure that you have on the thread. So the thread already has a loop structure by which you can grab it.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So the aspect of this robot that is unique is that it's not surgeon assisted or human assisted. It's a semi-automatic or automatic robot. A robot, once you, you know, obviously there are human component to it when you're placing targets. You can always move it away from kind of major vessels that you see.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
But I mean, we want to get to a point where one click and it just does the surgery within minutes.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's actually also one thing that we... are looking at ways to do multiple threads at a time, there's nothing stopping from it, you can have multiple kind of engagement mechanisms. But right now, it's one by one.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And, you know, we also still do quite a bit of just just kind of verification to make sure that it got inserted, if so, how deep, you know, did it actually match what was programmed in and, you know, so on and so forth.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, we try to place them all around three or four millimeter from the surface just because the span of the electrode, those 16 electrodes that we currently have in this version spans roughly around three millimeters. So we want to get all of those in the brain.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, each electrode can record from anywhere between zero to 40, as I mentioned earlier. But practically speaking, We only see about, at most, like two to three. And you can actually distinguish which neuron it's coming from by the shape of the spikes. So I mentioned the spike detection algorithm that we have. It's called BOSS algorithm, Buffer Online Spike Sorter. Nice.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It actually outputs, at the end of the day, six unique values, which are the amplitude of these negative going hump, middle hump, positive going hump, and then also the time at which these happen. And from that, you can have a statistical probability estimation of, is that a spike? Is it not a spike? And then based on that, you could also determine...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
oh, that spike looks different than that spike, must come from a different neuron.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Okay. And just to be clear, I mean, the labs do this, what's called spike sorting. Usually once you have these like broadband, you know, the fully digitized signals, and then you run...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
a bunch of different set of algorithms to kind of tease apart it's just all of this for us is done on the device on the device in a very low power custom you know built asic uh digital processing unit highly heat constrained highly heat constrained and the processing time from signal going in and giving you the output is less than a microsecond which is uh you know a very very short amount of time oh yeah so the latency has to be super short correct
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Oh, wow. Oh, that's a pain in the ass. Yeah, latency is this huge, huge thing that you have to deal with. Right now, the biggest source of latency comes from the Bluetooth, the way in which they're packetized. And we bin them in 15 millisecond time window. Oh, interesting.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, Bluetooth is definitely not our final... wireless communication protocol that we want to get to.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, the primary motivation for choosing Bluetooth is that, I mean, everything has Bluetooth. All right, so you can talk to any device. Interoperability is just absolutely essential, especially in this early phase. And in many ways, if you can access a phone or a computer, you can do anything.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So we have what's called a patient registry that people can sign up to hear more about the updates. And that was a route to which Nolan applied. And the process is that once the application comes in, it contains some medical records. And we, you know, based on their medical eligibility that there's a lot of different inclusion, exclusion criteria for them to meet.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And we go through a pre-screening interview process with someone from Neuralink. And at some point we also go out to their homes to, do a BCI home audit because one of the most kind of revolutionary part about having this in one system that is completely wireless is that you can use it at home.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You don't actually have to go to the lab and go to the clinic to get connectorized to these specialized equipment that you can't take home with you. So that's one of the key elements of when we're designing the system that we wanted to keep in mind. People hopefully would want to be able to use this every day in the comfort of their home.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And so part of our engagement and what we're looking for during BCI Home Audit is to just kind of understand their situation, what other assistive technology do they use. And we should also step back and kind of say that
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, movement is so fundamental to our existence. I mean, even speaking involves movement of mouth, lip, larynx. And without that, it's extremely debilitating. There are many, many people that we can help.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And I mean, especially if you start to kind of look at other forms of movement disorders that are not just from spinal cord injury, but from ALS, MS, or even stroke that leads you, or just aging, right? That leads you to lose some of that mobility, that independence, it's extremely debilitating.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Yeah, I mean, it's exactly that. I mean, I think if you are able to control a cursor and able to click and be able to get access to computer or phone, I mean, the whole world opens up to you. And
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I mean, I guess the word telepathy, if you kind of think about that as, you know, just definitionally being able to transfer information from my brain to your brain without using some of the physical faculties that we have, you know, like voices.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
You know, as much as you're learning to use that thing, that thing's also learning about you. Like our model is constantly updating the weights to say, oh, if someone is thinking about, you know, this sophisticated forms of like spiking patterns, like that actually means to do this, right?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
The end-to-end, you know, we say patient in to patient out, is anywhere between two to four hours. In particular case for Nolan, it was about three and a half hours. And there's many steps leading to the actual robot insertion, right? So there's anesthesia induction, and we do intra-op CT imaging to make sure that we're drilling the hole in the right location.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And this is also pre-planned beforehand. Someone like Nolan would go through fMRI and then they can think about wiggling their hand, and obviously due to their injury, it's not gonna actually lead to any sort of intended output, but it's the same part of the brain that actually lights up when you're imagining moving your finger to actually moving your finger.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's one of the ways in which we can actually know where to place our threads, because we want to go into what's called the hand knob area in the motor cortex, and as much as possible, densely put our electrode threads. So, yeah, we do intra-op CT imaging to make sure and double-check the location of the craniectomy. And the surgeon comes in, does their thing in terms of skin...
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
incision, craniectomy, so drilling of the skull. And then there's many different layers of the brain. There's what's called the dura, which is a very, very thick layer that surrounds the brain. That gets actually resected in a process called durectomy. And that then exposed the pia and the brain that you wanna insert.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And by the time it's been around anywhere between one to one and a half hours, robot comes in, does his thing, placement of the targets, inserting of the thread. That takes anywhere between 20 to 40 minutes. In the particular case for Nolan, it was just under or just over 30 minutes. And then after that, the surgeon comes in.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
There's a couple other steps of like actually inserting the dural substitute layer to protect the thread as well as the brain. And then, yeah, screw in the implant and then skin flap and then suture and then you're out.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So he was actually immediately after the surgery, like an hour after the surgery, as he was waking up, we did turn on the device, make sure that we are recording neural signals. And we actually did have a couple signals that we noticed that he can actually modulate. And what I mean by modulate is that he can think about crunching his fist. And you could see the spike disappear and appear.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And that's awesome. And that was immediate, right? Immediate after in the recovery room.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Obviously, there have been other, as you mentioned, pioneers that have participated in these groundbreaking BCI investigational early feasibility studies. So we're obviously standing on the shoulders of the giants here. We're not the first ones to actually put electrodes in the human brain. I mean, just leading up to the surgery, I definitely could not sleep.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
It's the first time that you're working in a completely new environment. We had a lot of confidence based on our benchtop testing or preclinical R&D studies that we the mechanism, the threads, the insertion, all that stuff is very safe and that it's obviously ready for doing this in a human, but there's still a lot of unknown, unknown about can the needle actually insert?
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
I mean, we brought something like 40 needles just in case they break. And we ended up using only one. But I mean, that was a level of just complete unknown, right? Because it's a very, very different environment. And I mean, that's why we do clinical trial in the first place to be able to test these things out.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So extreme nervousness and just many, many sleepless night leading up to the surgery and definitely the day before the surgery. And it was an early morning surgery. Like we started at seven in the morning. And by the time it was around 10.30, everything was done. But I mean, first time seeing that, well, number one, just huge relief that this thing is doing what it's supposed to do.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
And two, I mean, just immense amount of gratitude for Nolan and his family. And then many others that have applied and that we've spoken to and will speak to are true pioneers in every war. And, you know, I sort of call them the neural astronauts or neural knot. Yeah. Um, you know, these amazing, just like in the sixties, right? Like these, these amazing just pioneers, right.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
Um, exploring the unknown outwards in this case is inward. Um, but an incredible amount of gratitude for them to, uh, you know, just, just participate and, and play a part. Um, and, and it's a, it's a journey that we're embarking on together. Um, but also like, I think it was just, uh, that was a very, very important milestone, but our work was just starting.
Lex Fridman Podcast
#438 – Elon Musk: Neuralink and the Future of Humanity
So a lot of just kind of, uh, anticipation for, okay, what's what needs to happen next? Um, what are set of sequences of events that needs to happen for us to, you know, make it worthwhile for, um, uh, you know, both Nolan as well as us.