Auditory and auditory-tactile processing in congenitally blind humans

Studying blind humans is an excellent opportunity to investigate how experience might shape auditory processing. In everyday life, blind humans rely more on auditory information than sighted humans to recognize people, localize events, or process language. A growing number of studies have provided evidence that the increased use of the auditory system results in compensatory behavior in the blind. Blind humans perform better in perceptual auditory tasks, like pitch or duration discrimination, and in auditory language and memory tasks. Neural plasticity at different levels of the auditory processing stream has been linked to these behavioral benefits. In everyday life, many events stimulate more than one sensory system. Multisensory research has cumulated evidence that the integration of information across modalities facilitates perception and action control. Neurophysiological correlates of multisensory interactions have been described for various subcortical and cortical areas. There is evidence that vision plays a pivotal role in setting up multisensory functions during ontogeny. This article summarizes evidence for a reorganization of multisensory brain areas and reduced crossmodal interactions on the behavioral level following congenital visual deprivation.