The blind get a taste of vision

Abstract

In sensory substitution a given sensory modality acquires the functional properties of a missing one. This phenomenon is due to a reorganization of the sensory systems that are deprived of their normal input through a process called cross-modal plasticity [1]. 'Rewiring' studies carried out on ferrets [2] and hamsters [3] provided strong support for these phenomena. For example, lesions of central retinal targets induce the formation of new and permanent retinofugal projections into non-visual thalamic sites such as the auditory nucleus [3]. Single neurons in the auditory cortex of these rewired animals respond to visual stimuli and some of them respond equally well to auditory as to visual stimuli. Moreover, those cells that respond to visual stimuli show properties (e.g., orientation selectivity, motion and direction sensitivity) similar to those encountered in the visual cortex of normal hamsters.