Human spatial navigation via a visuo-tactile sensory substitution system.

Spatial navigation within a real 3-D maze was investigated to study space perception on the sole basis of tactile information transmitted by means of a 'tactile vision substitution system' (TVSS) allowing the conversion of optical images-collected by a micro camera-into 'tactile images' via a matrix in contact with the skin. The development of such a device is based on concepts of cerebral and functional plasticity, enabling subjective reproduction of visual images from tactile data processing. Blindfolded sighted subjects had to remotely control the movements of a robot on which the TVSS camera was mounted. Once familiarised with the cues in the maze, the subjects were given two exploration sessions. Performance was analysed according to an objective point of view (exploration time, discrimination capacity), as well as a subjective one (speech). The task was successfully carried out from the very first session. As the subjects took a different path during each navigation, a gradual improvement in performance (discrimination and exploration time) was noted, generating a phenomenon of learning. Moreover, subjective analysis revealed an evolution of the spatialisation process towards distal attribution. Finally, some emotional expressions seemed to reflect the genesis of 'qualia' (emotional qualities of stimulation).