a cross-modal recruitment of the occipital cortex during perceptual tasks such as Braille reading, tactile perception, tactual object recognition, sound localization, and sound discrimination. This may suggest that blind people can use their occipital lobe, generally used for vision, to perceive objects through the use of other sensory modalities. This cross modal plasticity may explain the often described tendency of blind people to show enhanced ability in the other senses. Perception versus sensing While considering the physiological aspects of sensory substitution, it is essential to distinguish between sensing and perceiving. The general question posed by this differentiation is: Are blind people seeing or perceiving to see by putting together different sensory data? While sensation comes in one modality – visual, auditory, tactile etc. – perception due to sensory substitution is not one modality but a result of cross-modal interactions. It is therefore concluded that while sensory substitution for vision induces visual-like perception in sighted individuals, it induces auditory or tactile perception in blind individuals. In short, blind people perceive to see through touch and audition with sensory substitution. Through experiments with a Tactile-visual sensory substitution (TVSS) device developed by Bach-y-Rita subjects described the perceptual experience of the TVSS as particularly visual, such that objects were perceived as if located in the external space and not on the back or skin. Further studies using the TVSS showed that such perceptual changes were only possible when the participants could actively explore their environment with the TVSS. These results have been underpinned by many other studies testing different substitution systems with blind subjects such as vision-to-tactile substitution, vision-to-auditory substitution and vision-to-vestibular substitution Such results are also reported in sighted subjects, when blindfolded and deliver further support for the sensorimotor contingency theory. Different applications Applications are not restricted to disabled persons, but also include artistic presentations, games, and augmented reality. Some examples are substitution of visual stimuli to audio or tactile, and of audio stimuli to tactile. Some of the most popular are probably Paul Bach-y-Rita's Tactile Vision Sensory Substitution (TVSS), developed with Carter Collins at Smith-Kettlewell Institute and Peter Meijer's Seeing with Sound approach (The vOICe). Technical developments, such as miniaturization and electrical stimulation help the advance of sensory substitution devices. In sensory substitution systems, we generally have sensors that collect the data from the external environment. This data is then relayed to a coupling system that interprets and transduces the information and