I actually read about this technology several years ago in a wired article called Mixed Feelings. The article is extremely interesting, so much so that i re-read it today. But if you don't feel like reading the entire thing here are the parts relevant to the above video / story. First it talks about why this works.
It turns out that the tricky bit isn't the sensing. The world is full of gadgets that detect things humans cannot. The hard part is processing the input. Neuroscientists don't know enough about how the brain interprets data. The science of plugging things directly into the brain — artificial retinas or cochlear implants — remains primitive.
So here's the solution: Figure out how to change the sensory data you want into something that the human brain is already wired to accept, like touch or sight. The brain, it turns out, is dramatically more flexible than anyone previously thought, as if we had unused sensory ports just waiting for the right plug-ins. Now it's time to build them.
Then it refers to an experiment that was the predecessor to the above device.
Paul Bach-y-Rita built his first "tactile display" in the 1960s. Inspired by the plasticity he saw in his father as the older man recovered from a stroke, Bach-y-Rita wanted to prove that the brain could assimilate disparate types of information. So he installed a 20-by-20 array of metal rods in the back of an old dentist chair. The ends of the rods were the pixels — people sitting in the chairs could identify, with great accuracy, "pictures" poked into their backs; they could, in effect, see the images with their sense of touch.
The mouthpiece was the next itteration.
Having long ago abandoned the vaguely Marathon Man like dentist chair, the team now uses a mouthpiece studded with 144 tiny electrodes. It's attached by ribbon cable to a pulse generator that induces electric current against the tongue. (As a sensing organ, the tongue has a lot going for it: nerves and touch receptors packed close together and bathed in a conducting liquid, saliva.)
Here is the most relevant part.
During a long brainstorm session, they wondered whether the tongue could actually augment sight for the visually impaired. I tried the prototype; in a white-walled office strewn with spare electronics parts, Wicab neuroscientist Aimee Arnoldussen hung a plastic box the size of a brick around my neck and gave me the mouthpiece. "Some people hold it still, and some keep it moving like a lollipop," she said. "It's up to you."
Arnoldussen handed me a pair of blacked-out glasses with a tiny camera attached to the bridge. The camera was cabled to a laptop that would relay images to the mouthpiece. The look was pretty geeky, but the folks at the lab were used to it.
She turned it on. Nothing happened.
"Those buttons on the box?" she said. "They're like the volume controls for the image. You want to turn it up as high as you're comfortable."
I cranked up the voltage of the electric shocks to my tongue. It didn't feel bad, actually — like licking the leads on a really weak 9-volt battery. Arnoldussen handed me a long white foam cylinder and spun my chair toward a large black rectangle painted on the wall. "Move the foam against the black to see how it feels," she said.
I could see it. Feel it. Whatever — I could tell where the foam was. With Arnold ussen behind me carrying the laptop, I walked around the Wicab offices. I managed to avoid most walls and desks, scanning my head from side to side slowly to give myself a wider field of view, like radar. Thinking back on it, I don't remember the feeling of the electrodes on my tongue at all during my walkabout. What I remember are pictures: high-contrast images of cubicle walls and office doors, as though I'd seen them with my eyes. Tyler's group hasn't done the brain imaging studies to figure out why this is so — they don't know whether my visual cortex was processing the information from my tongue or whether some other region was doing the work.
The thing that really interests me is this "Thinking back on it, I don't remember the feeling of the electrodes on my tongue at all during my walkabout. What I remember are pictures: high-contrast images of cubicle walls and office doors, as though I'd seen them with my eyes."
Click the title for the short BBC article that accompanies the video.
