Similarly, people have trouble discriminating color patches that are small. The optic nerve that leaves your eye that goes back to your visual cortex is a cable with millions of fibers in it.
determine that pattern of DNA methylation determines whether this particular gene will be switched on, say to make an optic nerve , or switched off so that it's becomes a liver cell. And that happens as we're in the womb and we become an embryo. And that's the epigenome. These chemicals that turn genes on and off is the epigenome.
This is the pituitary gland here. This would be the optic nerve connecting to the eyes. And just as the optic chiasm-- just as the optic nerves form the optic chiasm, they fuse.
My spinal cord inflammation, I've been able to recover quite well from. But my optic nerve inflammations or my optic neuritis-- that was much harder. So gradually in my 20s, my vision did decrease the level that it is now.
the subtitle given by my co-authors Stu Card and Jock Mackinlay to call it Using Vision to Think. That is your eyes are not just input devices but they're ways of solving problems; that the optic nerve and your mind is well designed to in a few hundred milliseconds pick out trends, clusters, gaps, and outliers if the visual representations are appropriate in terms of colors, size, shape, and proximity.
why it is we get old and how it is we reverse it. But but for this this model what we're doing is we're introducing a set of three genes into this optic nerve at the back of the eye and turning them on for 6 to 8 weeks.
What we did in collaboration with a lab across the street, Xi He's lab, after we put the virus in the eye of a mouse, we pinched the back of its optic nerve . And what normally happens is-- I'm sure you can guess-- is the nerve dies.
All of them, apparently. Your pupil is the end of your optic nerve , so you can see-- just like your teeth are the end of your skeleton.
And by dint of how it falls on one retina relative to the other, it assigns it a place in space that's either in front or behind the other image. On the place where the optic nerve leaves the retina and goes to the rest of the brain.
head now there's some interesting facts about this this pathway one is the bandwidth of this connection does anyone know what the bandwidth of the optic nerve is it's about 10 megabits per second um which is really interesting when you think about it because it's it's when I when I read that study and
A lot of people don't know that. You can touch your brain if you touch your eye. Um so, the optic nerve gets old and what we've discovered if it gets damaged or gets old, it's not working. But the nerves for most the most part, if you're old, are still there.
And that's where the light hits. And at that point there are a lot of nerves that coalesce into the optic nerve that runs to the brain by just a few millimeters. So, the brain is here. The eye is actually part of the brain.
So here we see our SCN again. And we know that there's a special projection from the eye via the optic nerve to the SCN. It's called the retinohypothalamic tract.
And those discoveries led to the identification of another light sensor within the eye called a photosensitive retinal ganglion cell. About 1 out of every 100 of those ganglion cells that form the optic nerve is directly light sensitive using a special photopigment called melanopsin, or OPN4. And it's these photosensitive retinal ganglion cells that allow us to align the internal data to the external world.
An axolotl loses its limb, it will regrow a limb. And so what you're looking at is a stain of the optic nerve that's been crushed, and you can see where the crush ends.
And as this bundle of nerves has to leave the retina, it means we can't actually have any photo receptors on there. So what this means is that any information that is projected onto that optic nerve , which was known as the blind spot, will disappear, because we've never encoded it in the first place.
to these cavities in the brain called the ventricles um not quite right um he was close though what we know is that the eyes send out an optic nerve which eventually um one or two synapses later uh sends input into the visual part of the brain which is actually in the back of the
I don't think anyone wants to go back to high school. But this is the way it works. And we chose the optic nerve because it's a safe and close system, not because it should work better in optic nerves. In fact, we've now done it in mice in my lab for the brain. Uh we're doing
But it's really just water flowing out of the jungle into the sea. And in the book, "How to Astronaut," I talk about having those particles hit my optic nerve and seeing white flashes.
An axolotl loses its limb, it will regrow a limb. doesn't have the TET genes in its eye, you cannot restore the growth of its optic nerve .
a book hopefully this one or looking at a facial expression each of those experiences trigger a different Cascade of neural events the light comes into your eye goes back to your retina into the optic nerve there are chemical reactions neurotransmitters transport the information uh across these neural networks this is the basic building
And then these are the ganglion cells, which gather this information. And then, of course, it's the axons of the ganglion cells that form the optic nerve . And we worked on mice originally and then humans, and to our amazement, discovered that you don't need the visual cells at all.
And what normally happens is-- I'm sure you can guess-- is the nerve dies. If we're old, even if we're young adults, we will not grow back an optic nerve . If we break our spine, we will not grow back a spine and a spinal cord.
An axolotl loses its limb, it will regrow a limb. You might say, David, a crushed eye, it's unlikely I'm going to have a crushed optic nerve .
And of course, this image is projected through the lens onto the back of our eye, which is known as the retina, which is covered in thousands of little photo receptors that encode all of the visual information, and then send it through the optic nerve to different parts of the visual cortex.
He's going to be defined by his ability to continue to live a full life. The other was Marty Bailey, blinded in Afghanistan when a grenade went off in the foxhole that he was in right next to him, severed his optic nerve . And it's the same for him.
Similarly, people have trouble discriminating color patches that are small. The other reason is that in your retina, every cone cell in the fovea sends a fiber out to the optic nerve that goes
Today, those peripherals might be your printer, your scanner, your SCADA controller, your MRI machine, your car, your avionic, your 3D printer. You can understand why that would be a bit freaky, but of course, in the future, those peripherals might also include your optic nerve , your cochlea, and the stumps of your legs. When your computer boots up, the TPM can ask your bootloader for a signed hash of itself and verify that the signature of the hash comes from a trusted party, someone you trust.
conscious mind perceives when you look at the road. Let me show you now the image that your retina picks up. Your retina picks up an image that's only clear in the very center of the area that you're fixating on, and it's very fuzzy outside of that and it has a black spot that you'll see over here which is the blind spot from where your optic nerve attaches to your retina. What your brain does is it takes this and it uses this data and it uses the data from