Mind & Brain / Senses

I'm sitting at a table draped in black, surrounded by black curtains. Candles, spheres, and unfamiliar symbols have been placed before me. My right hand, arms, and head are strapped with wires, and my mouth is filled with electrodes. I'm blindfolded.

Although this may sound like a scene for a Black Mass, it's even stranger than that: I'm trying to see with my tongue.

The gear I'm wearing was invented by Paul Bach-y-Rita, a neuroscientist at the University of Wisconsin at Madison. Bach-y-Rita has devoted much of his career to a single, revolutionary concept: that our senses are interchangeable. The brain, Bach-y-Rita and many other neuroscientists believe, is an organ of astonishing plasticity: If one part of it is damaged, another part can serve the same function. To prove the point, his collaborator Kathi Kamm, a professor of occupational therapy at the university's Milwaukee campus, has strapped a small video camera to my forehead and connected it to a long plastic strip hanging from my mouth. A laptop computer reduces the camera's image to 144 pixels. Those pixels are converted to an electric current that is sent to the business end of the plastic strip—a 12-by-12 grid of electrodes that rests on my tongue.

Kamm sits down in front of me. She says she's holding a ball, but I can't hear a sound as she rolls it back and forth over the cloth-covered table. She says the ball will soon be rolling toward me—to my left, my right, or straight at me—but my eyes and ears have no way to tell where it's going.

That leaves my tongue. It has more tactile nerve endings than any part of the body other than the lips. What the camera sees is zapped onto my tongue's wet, conductive surface. As Kamm rolls the ball, my blindfolded eyes see nothing, but a tingling passes over my tongue. When she sends the ball my way, my hand leaps out to the left.

I've caught it.

"We don't see with our eyes," Bach-y-Rita is fond of saying. "we see with our brains." The ears, eyes, nose, tongue, and skin are just inputs that provide information. When the brain processes this data, we experience the five senses, but where the data come from may not be so important. "Clearly, there are connections to certain parts of the brain, but you can modify that," Bach-y-Rita says. "You can do so much more with a sensory organ than what Mother Nature does with it."

Bach-y-Rita, who is 69, looks like a cross between Albert Einstein and Harpo Marx. His hair springs from his head in a wild gray Afro, and his face often bears a comic, knowing smirk. He owes his iconoclastic spirit to his late father, he says. A professor of Spanish at the City University of New York, with a passion for 16th-century Catalonian poetry, Pedro Bach-y-Rita nearly destroyed his career in 1947 by organizing the country's first civil-rights strike at a university. He encouraged his children to be equally rebellious. Rather than raise Paul as a Catholic like himself or Jewish like his wife, for instance, he urged him to choose his own religion. Paul chose to become a Swedish Lutheran—he liked the pastor at Bernadotte Lutheran Church in the Bronx. But when he later won a scholarship to a Lutheran college, he turned it down. He didn't feel right accepting the money, he explained, since he was not a believer.

In 1958, at the age of 65, Pedro Bach-y-Rita suffered a stroke that left him confined to a wheelchair, hardly able to move or speak. Paul's brother, George, was a medical student at the University of Mexico at the time. Rather than let his father vegetate in a nursing home, George brought him to his house and put him to work. "It was tough love," Paul says. "He'd throw something on the floor and say 'Dad, go get it.'" The neighbors would watch in dismay as the old man struggled to sweep the porch. "But for him, it was so rewarding," Paul says. "This useless man was doing something."

Neurologists in those years believed that brain damage was impossible to reverse. If a stroke caused memory loss, paralysis, or dementia for more than a few weeks, the condition was permanent. Nevertheless, after three years Paul's father recovered completely. He went back to teaching and worked for another five years. When he died in 1969 at the age of 73, it was from a heart attack while hiking at an altitude of 9,000 feet in the mountains of Colombia.

The neuropathologist who autopsied Pedro's brain later published a paper on the case in the American Journal of Physical Medicine, complete with pictures of Pedro's devastated brain. "It was shocking," Paul says. "My father had recovered so much that we'd figured he didn't have much brain damage." Why did he recover, Paul remembers thinking, when everyone else said he couldn't?