MIDDLETON, Wis.--Some people have a strange condition called synesthesia. Their senses are cross-wired in such a way that they "see" sounds or "hear" sights. Now a U.S. company has invented a device that enables people to "touch" sights too. It was developed to help blind people see again.
The device is called the BrainPort. It includes a tiny video camera mounted on a pair of sunglasses. The camera is wired to a handheld unit that converts the camera's video signal into electrical pulses. A second wire relays those pulses from the unit to a "lollipop," a 9-square-centimeter (1.4-square-inch) array of tiny electrodes (rods through which an electric current flows).
Each electrode on the lollipop corresponds to a pixel (dot of light) on the image captured by the video camera. If the pixel on the upper right-hand corner of the image is white, the electrode on the upper right-hand corner of the lollipop receives a strong electrical pulse. If the pixel is black, no pulse occurs.
When the lollipop is placed on a person's tongue, the electrodes stimulate the layer of touch-sensitive nerves in the tongue's surface. The tongue tingles like Pop Rocks. In a matter of time, the person's brain learns to interpret the information coming from the tongue as if it were coming from the eyes, says Aimee Arnoldussen, a neuroscientist at Wicab, the company that makes the BrainPort The pattern of electrical stimulation on the tongue is perceived as an image--the image picked up by the video camera on the sunglasses. "It becomes a task of learning, no different than learning how to ride a bike," she told Scientific American.
People trained to "see" with the BrainPort have learned very quickly how to locate doorways, tell the difference between cups and forks at a table, and read numbers and letters. The emotional reactions have been no less remarkable, the first sight of a letter moving one blind man to tears.
The people in northeastern India build bridges in an original way. They thread together the living roots of Ficus elastica trees and train them to grow high over streams in the forest. Over a period of 20 years, the roots are guided into the shape of a bridge, complete with handrails and a footpath, that can hold the weight of many people at once.