Use of an ultrasonic echolocation prosthesis by early visually deprived cats.

The aim of this study was to design an animal model of sensory substitution in the case of blindness. Six kittens were binocularly enucleated; as adults, they were fitted with an ultrasonic echolocation prosthesis. This device provided the animals with auditory signals that coded distance and direction of obstacles. Animals were trained by operant conditioning to use the prosthesis in various behavioral situation. The results showed that visually deprived animals tried to solve the task using natural information and that they only used artificial information provided by the prosthesis when they were unable to succeed with natural cues. Under these conditions, it was asserted that in a jumping test these animals evaluated depth by means of the prosthesis; in a locomotion task in a maze, it was also demonstrated that they could use the prosthesis for avoiding obstacles.