Abstract
Sensory deprivation from birth leads to a number of manifestations ranging from anatomical reorganisation to behavioural and cognitive changes. We will illustrate these changes in humans that have been deprived of vision since birth (congenital blindness, CB). We took advantage of a sensory substitution device coined Tongue display unit (TDU) that uses the tongue as a medium to transmit “visual” information to the brain. By using MRI whole brain voxel-based morphometry, we show that the visual pathways of the blind are atrophied. Their visual cortex however can be recruited in tasks involving the somatosensory system. For example, CB can discriminate the orientation of a stimulus, detect motion and motion direction. In doing so, they recruit cortical areas involved in visual perception such as the visual cortex and area MT. Finally, TMS of the visual cortex induces parasthesiae on the tongue that are somatotopically organized. Our data argue for crossmodal plasticity in early blindness that is training-dependent.