Preserved Functional Specialization in Sensory Substitution of the Early Blind

Abstract

It has long been established that the occipital cortex of early blind animals and humans is activated by nonvisual stimuli (Rauschecker 1995). Using functional magnetic resonance imaging, we have demonstrated recently that the middle occipital gyrus (MOG) of early blind humans retains its function in spatial localization and is activated in auditory and tactile spatial tasks (Renier et al 2010). Sound localization performance was directly correlated with amount of activation in MOG. Currently we are using a visual-to-auditory substitution device to investigate whether cortical areas in the visual ventral stream also retain their function in face and object recognition when they are stimulated by auditory and tactile “objects”. The results should make a valuable contribution not only to further understanding of this fundamental question regarding cortical plasticity but also to aid blind persons in everyday practical situations.