A taste for space

Abstract

Can we see only with the retina? Paul Bach-y-Rita has previously shown that people, including the blind, can also see when a 2-D array of tactile stimulators transduces signals from a camera – as long as the camera is actively controlled by the observer (as the eye is). Recently, Bach-y-Rita and Paul Kaczmarek at the University of Wisconsin have improved the system by trading tactile for mild electrical stimulation, and placing the stimulators inside the mouth on the tongue. Because of the sensitivity of the tongue and the presence of saliva, which is a good conductor, smaller currents can be used to deliver stimulation that is more uniform. The 144-electrode system, which, according to Bach-y-Rita requires 50 hours of training for proficiency, has already been used to pilot subjects in simple navigation tasks. The next step will be to create a wireless link to an inconspicuous camera, to be mounted on spectacles. Another application – to help divers see in murky waters with a sonar rather than a video camera – has already been tested by the US Navy. MW