Cross-Modal Plasticity in Auditory and Visual Systems

Neuro-plasticity is the neuronal system ability to modify and recover itself after the occurrence of impairment and injuries. Following the abolition of a sensory modality، modifications will be applied to other modalities and their cortical function in a way that the processing of these modalities not only will happen in their own specific cortical area، but also in those areas that have developed injuries. Therefore a compensatory process will happen in the regions، which are deprived of their own sensory inputs. This phenomenon is known as cross-modal plasticity. This paper investigates various aspects of cross- modal plasticitycity between auditory and visual systems، and the latest scientific findings in this field are explored. Scientific articles published in Pubmed، Google Scholar، Science Direct websites using key words Cross-modal plasticity and Auditory، Neuronal plasticity and Visual، Neuronal plasticity between 1980 and 2013 were investigated. Ninety five articles were found using the mentioned methods. All titles and abstracts were studied thoroughly، and 70 articles with the desired concept were selected eventually. The extent of cross-modal plasticity is related to the age at which the deprivation of a certain sense occurs. In blind people، Auditory and Somatosensory senses take up the occipital space، and result in the augmentation of hearing، recalling memories، spatial localization، musical understanding and reading Braille. In deaf people on the other hand، visual and somatosensory occupy parts of the temporal lobe and result in improvement of peripheral visual signals processing، and enhancement of tactile sense، and active movements.