How Neuralink plans to give blind people sight

HostWe usually think of seeing as something our eyes do, like two cameras taking a video of the world. But if those cameras break, or if the cord connecting them to the brain gets cut, the part of the brain that actually makes the movie is still there, just sitting in the dark. There's this idea that we could just walk around the broken eyes and talk to the brain directly. How do you even start to give someone sight if their eyes don't work at all?

GuestWell, you have to look at what the eye is actually doing for us. Its main job is to take light and turn it into tiny electrical zaps. Those zaps travel down a thick cord to the very back of your head, which is where your brain actually builds the picture you see. If the eyes or that cord are damaged, the brain is like a TV screen with no signal. The plan here, which they call Blindsight, is to plug a new cable directly into the back of the head. They use a very small chip with over a thousand tiny, flexible wires. These wires are much thinner than a human hair. A robot stitches them into the part of the brain that handles sight, which is called the visual cortex. Instead of waiting for the eyes to send a signal, a camera on a pair of glasses takes in the world, sends that data to a computer, and the computer tells those tiny wires to zap the brain in a specific pattern.

HostBut it feels like there's a big gap between a camera and a brain. I mean, if you just start zapping the back of my head, how does my brain know that a certain zap means there's a door in front of me or a cat at my feet?

GuestThat's the hardest part of the whole thing. The brain has to learn a new language. When those tiny wires, or electrodes, poke the brain with a little bit of power, the person sees a tiny dot of light. Scientists call these dots phosphenes. Think of them like the glowing dots on a giant scoreboard at a game. If you turn on just one dot, it doesn't mean much. But if you turn on hundreds of them in the right spots, you can start to see a shape. At first, it's not going to look like what you and I see. It'll be very blocky and simple. The goal right now is to get the brain to see enough of these dots that the person can find a doorway, walk down a sidewalk without hitting a pole, or maybe even play a very simple video game.

HostSo it's more like seeing a map made of glowing dots than actually seeing a face or a tree. I'm struggling to see how that's helpful for someone who has been in the dark for years. Is a bunch of dots really enough to change how someone lives?

GuestIt's a fair point, because it's definitely not high-definition. The person leading this work even said the first version might look like those old video games from the seventies, like Atari graphics. It's very rough. But for someone who sees absolutely nothing, being able to tell where a window is or seeing the outline of a person walking toward them is a massive shift. And the government actually gave this project a special status recently, called a breakthrough device tag. That's basically a fast track to help them get through all the red tape and testing because the potential to help people is so big. They're not just trying to fix what was lost, either. Since the signal is coming from a camera and not a living eye, they think they can eventually show the brain things that human eyes can't even see, like heat maps or ultraviolet light.

HostWait, that sounds like something out of a movie. You're saying they might be able to see like a honeybee or a night-vision camera? But wait, if someone has been blind from birth, their brain never learned how to see in the first place. Does this even work for them?

GuestThat's one of the biggest questions the team is still chasing. If someone had sight and then lost it, the brain already has the maps and the paths ready to go. It remembers what a line or a curve looks like. But if someone was born blind, that part of the brain might have moved on to other jobs, like helping them hear better or feel things more sharply with their hands. There's a real worry that the brain might not be able to switch back. But the team is hopeful because the brain is very good at changing how it works when it gets new information. They're starting with people who lost their sight later in life first, just to prove the wires can actually talk to the brain without causing problems.

HostIt's wild to think about. We always treated the eye as the only way to get the world inside our heads.

GuestWe're still trying to find out if a brain that has never seen a single ray of light can be taught to read those glowing dots and turn them into a world.

HostThe front door might be broken, but it turns out we're finding a way to wire the house from the inside out.