"You don't see with your eyes. You see with your brain." — Paul Bach-y- Rita, neuroscientist, 1934-2006
In 1959 Pedro Bach-y-Rita, an immigrant from Spain and a poet in the Catalan language, suffered a massive stroke. Doctors told his family that he would never walk or talk again. His son, a medical student at the time, didn't accept their prognosis. He set up a grueling regime of physical therapy for his father and it was wildly successful. In just a year his father was teaching again at the College of New York. Pedro died of a heart attack 15 years later while trekking in Columbia. An autopsy proved that the stoke he'd suffered all those years earlier had, indeed, deprived him of the use of much of his brain, including the areas that control motion and motor activity.
Pedro had another son, also a doctor, Paul Bach-y-Rita. Paul founded the new study of neuroplasticity. He wasn't surprised by the results of the autopsy. The results confirmed his own research. He believed the brain to be far more malleable than previous researchers had given it credit.
Some of you may know the NPR show Radiolab. It specializes in stories that will surprise you. It can be a little hokey, even a little annoying at times in its setups and asides, its jokes and banter and gimmicks, but when the show gets down to business it can rock your world.
Its presenters, Jad Abumrad and Robert Krulwich seem to believe that half of what you already know is just wrong, and the rest is entirely suspect. They set about proving their point every weekend, but with a lot of recycled material thrown in. That's great for me. I love their premise. It's the basis of all my thinking. Being proven wrong is the beginning of learning. It's kind of fun, too. A recent show (a 2014 rebroadcast) was that kind of fun.
If you're a stupid as I am you've probably been assuming that your eyes do the seeing. Maybe that's not all that stupid because that's what nearly everyone thought before Paul Bach-y- Rita. You probably thought that your eyes gather in all the visual information before you and then somehow project that image back to the brain. Oh, fool! Turns out they only do about half that. A single eye does take in visual information through its two million light sensors but what it sends to the brain is nothing more than pulses of electricity. The brain then does all the heavy lifting by creating images out of only this. If your mind isn't blown yet, there's more.
The Radiolab story was about a woman named Emily who had lost her eyesight in an auto accident. She'd been chosen for a study of a new device that can return sight to the blind, even give sight to those who'd never had it. The restored sight is limited, as Emily explained, but it's enough for her to navigate the world around her and identify individual objects and even letters. Nothing was done to restore her eyesight. That's gone forever. With a small live-action camera attached to a pair of sunglasses and a “popsicle stick” in her mouth, Emily learned to see with her tongue. Yes, I said see with her tongue! I mean that literally.
Radiolab didn't go much beyond Emily's story but there is a story behind her story. Paul Bach-y-Rita and the instrument he invented gave her this extraordinary gift. He'd been tinkering on a device that could turn images seen by a camera into electrical impulses that would be felt. At his laboratory he came up with an electrode array that could fit into the palm of the hand connected to a camera. One day while experimenting with it he needed both hands for something and slipped it into his mouth for a moment. It was an ah-ha moment. The array filled his tongue with sensations so detailed they reproduced something like the process that occurs with healthy eyes.
The tongue was the perfect portal for restoring sight. Tongues are packed with nerve endings close to its surface and the moisture of that environment enhances electrical transmission. Each of the 400 electrodes arranged in a grid “light up” in patterns sent from the camera. Exactly how the brain accomplishes the miracle of translating neural impulses from the tongue into vision is still not completely understood, but that's not to say that it's anymore miraculous than eyesight itself. The process for both is substantially the same. Whether felt or seen, nerve pulses are similarly sent to the brain and the brain creates images. The brain constructs images from the pulses sent to it.