Crossmodal plasticity and hearing capabilities following blindness.

Valuable insights into the role of experience in shaping perception can be obtained by studying the effects of blindness or other forms of sensory deprivation on the intact senses. Blind individuals are particularly dependent on their hearing and there is extensive evidence that they can develop superior auditory skills, either as a result of plasticity within the auditory system or through the recruitment of functionally relevant occipital cortical areas that lack their normal visual inputs. Because spatial processing normally relies on close interactions between vision and hearing, much of the research in this area has focused on the effects of blindness on auditory localization. Although enhanced auditory skills have been reported in many studies, some aspects of spatial hearing are impaired in the absence of vision. In this case, the effects of crossmodal plasticity may reflect a balance between adaptive changes that compensate for blindness and the role vision normally plays, particularly during development, in calibrating the brain's representation of auditory space.