00:00Imagine using technology to restore eyesight to the blind.
00:05Elon Musk's Neuralink Brain Implant Company believes that they can do it, and to a lot
00:10of people that might sound like biblical grandstanding, but there is good scientific evidence that
00:16says digital sight may be a very real possibility.
00:22And this is how Neuralink Brain Implants will cure blindness.
00:30The first trick is understanding what vision even is.
00:35There are certain aspects of human eyesight that are well understood, but overall, we
00:39really don't know how this works.
00:42Light as we commonly know it is essentially just electromagnetic radiation that exists
00:47within our visible wavelengths.
00:50That radiation is contained inside energetic particles called photons.
00:54These photons have no mass, no electrical charge, and they are in a constant state of motion,
01:00hence the speed of light.
01:02Photons of light enter your eyeball and are focused by a lens onto a layer of tissue near
01:07the back of the eye.
01:09That is your retina.
01:11It's made of special cells called photoreceptors, and they can transform electromagnetic energy
01:16into electrical signal.
01:18That signal flows through the optic nerve and into the visual cortex of the brain, at which
01:23point billions of neurons inside the brain translate the electrical signal into everything
01:29that you can see.
01:30We know that the neural network processes visual information in layers.
01:34There are basic, low-level processing layers for things like edge detection, identifying curves,
01:40recognizing objects.
01:42But when we get to higher levels of processing, like color encoding, no one really knows what's
01:48going on in there.
01:49When a person loses their ability to see, it's almost always a problem associated with the
01:54eye or the optic nerve, not the visual cortex.
01:58So the majority of our treatments right now are focused on regenerating that physical tissue.
02:03In most scenarios, that doesn't work.
02:07But this also means that it's just the input device that isn't working.
02:11The processing system is still intact, so in theory, we can plug electrical signals straight
02:17into the visual cortex and create vision in the same way as the eye and the optic nerve.
02:23This does sound crazy, but it has been done before.
02:27Actually the first experiments with stimulating vision through electrical signals date back
02:32all the way to the late 1920s.
02:35In order to understand this, we need to learn a new word first, photosphene.
02:40This is a phenomenon where you see light in your visual field without any light entering
02:44your eye.
02:45Do you ever see stars with your eyes closed?
02:47Do you see patterns of light when you rub your eyes?
02:51These are photosphenes that you are seeing.
02:54Photosphenes can be induced by mechanical, electrical, or magnetic stimulation of either the retina
02:59or the visual cortex.
03:01So you'll see them if you take a blow to the head, but you'll also see them if you get
03:05an electrical shock in the right portion of your brain.
03:09This was first confirmed by the famous neurologist Otfred Forrester in 1929.
03:15Decades later, in 1968, two scientists at the University of Cambridge refined the procedure
03:21by connecting electrodes into the brain of a 52-year-old blind patient and wiring them
03:26to an array of radio devices.
03:28When certain radio signals were transmitted into the brain, the patient experienced sensations
03:34of light.
03:35When just one electrode was stimulated, the patient would see a single, very small spot
03:40of white light in a consistent location.
03:43This is the photosphene.
03:45And it was found that as long as the electrodes were spaced more than two millimeters apart,
03:50the resulting photosphenes can be easily distinguished from each other.
03:53So by stimulating multiple electrodes at once, the patient would be caused to see patterns
03:59of light.
04:00This experiment was repeated in 1974 at the University of Utah.
04:05They placed a rectangular grid of electrodes into the visual cortex, four across by three
04:10deep, and then they used these electrodes to project patterns of braille dots into the
04:14patient's vision, creating a very primitive, yet effective visual prosthetic, the first
04:20of its kind.
04:21Now of course, opening up a person's skull and sticking wires into their brain just to
04:25show them braille letters isn't really helping anyone, but it is a solid foundation to build
04:31on.
04:32We know that Neuralink is working on an application called Blindsight.
04:36The companies follow up to their current app, Telepathy.
04:39Telepathy is all about output.
04:41Neuralink electrodes detect activity spikes from within the brain and convert those to
04:45digital signals that are transmitted wirelessly into a computer, so all that the user has
04:50to do is think about moving a cursor on a screen, and telepathy will make it happen.
04:56Now Blindsight becomes about input.
04:59Neuralink has to use the electrodes to inject electrical signals into the brain to stimulate
05:04the neurons and produce the photosphene effect.
05:07This would start with a digital camera, like a GoPro strapped to a person's head or
05:11something like those Ray-Ban smart glasses.
05:13These devices are already purpose-built for converting photons into electrical signal just
05:18like the retina.
05:20Then the Neuralink device can take the place of the optic nerve, transmitting the electrical
05:24signals directly into the neural networks of the visual cortex and stimulating the photosphene
05:29to create a visual representation of what the camera is seeing.
05:33The idea is that the smaller the electrode, the smaller the photosphene that the patient will
05:38see, so instead of seeing a big dot in their vision, the Neuralink user might see something
05:43more like a pixel on a display.
05:45Using Neuralink's R1 robot, these electrodes can be placed into a highly accurate grid on
05:50the visual cortex, just like the old experiment from the 70s, but with orders of magnitude higher
05:56resolution.
05:57Now that's not going to instantly create any kind of photorealistic image, but the Neuralink
06:02user will most likely see is something like an old Atari video game.
06:06It won't be particularly useful for seeing details, but it might be good enough for a
06:10person to see edges and large objects so that they don't bump into stuff.
06:15More resolution in the Neuralink image would require more electrodes.
06:19Neuralink is currently maxed out at around 1,000, but they are hoping to reach 3,000 or
06:24even 6,000 in the near term and as many as 16,000 electrode channels within the next year
06:30or two.
06:31But it's the amount of bandwidth going through the device that is the big limiting factor
06:35right now.
06:37We all know what happens to a computer when it starts working too hard.
06:41It gets hot, and you don't want a computer implanted in your skull to start getting hot.
06:47So the efficiency of the computer chip and the performances of the battery play important
06:51roles as well.
06:53Also, to give a person full panoramic vision, they would need to have two Neuralink implants,
06:58one on each hemisphere of the brain.
07:00Vision from your right eye is processed in the left side of the brain and vice versa.
07:05To make things even stranger, the image projected onto your retina by the lens in your eyeball
07:09is actually cast upside down.
07:12Your brain doesn't flip the image because it doesn't receive a projected image, just a series
07:16of nerve impulses that it decodes in such a way that everything is perceived correctly.
07:21Actually, the whole process of seeing things the right way up is pretty strange.
07:26If you tilt your head over 90 degrees, your perception of the world doesn't tilt.
07:30You still know up and down, even when you're sideways.
07:34This is the kind of stuff that still needs to get figured out, and that's going to take
07:37a lot of trial and error before we even begin to get things right.
07:42It won't be an easy process, don't be expecting a Neuralink to replace virtual reality or augmented
07:47reality headsets anytime soon.
07:50But there is potential for computer-enhanced vision to go far beyond the human eye at some
07:55point in the future, and this would be long in the future, but in theory, we can go way
08:00beyond just projecting a movie into your head.
08:03What we know as light is simply electromagnetic radiation that exists within our visual spectrum
08:09of wavelengths, but there is light that exists in higher wavelengths than what we can see.
08:15That's ultraviolet light, and there is light that exists in much longer wavelengths as well.
08:20That's infrared.
08:22We can't see this radiation, but we know it exists, and we can easily create digital image
08:27sensors that can read this light for us and convert it into a visible spectrum.
08:32Now if we go back to that idea of strapping a GoPro to a person's head and replace that with
08:37an infrared camera or an ultraviolet light detector, now we've just unlocked a whole new way for
08:43a person to perceive the world.
08:45We can go way beyond our conscious experience, deeper into the nature of the universe and
08:50existence, like taking a high-powered psychedelic drug without any of the weird side effects.
08:57Anyway, coming back around to real life, can Neuralink restore sight to the blind?
09:01Yes, but not in the sense of flicking a switch and turning your eyes back on, but more in the sense
09:07of being able to restore a very rudimentary visual perception of the outside world, like
09:12living inside your own low-res monochrome video game.
09:15But as the device capability improves over time, a long time, resolution will improve as well.
09:22As for those higher level functions, would you ever see colors? Could you look around in every
09:27direction you want? Can you tilt your head and still know which way is up? Well, these are secrets
09:33that still need to be revealed.
Comments