Residual vision and plasticity after visual system damage

This is an introduction to a special issue of the journal Restorative Neuro logy and Neuroscience which contains a series of papers presented at a sate llite symposium held in conjunction with the European Forum of Neuroscience , Berlin, July 1-2, 1998, entitled "Visual System Damage: Residual Vision a nd Plasticity". The symposium highlighted research findings both from anima ls and humans which sustained brain injury in early development and in adul thood. The findings demonstrate the degree of residual vision the injured b rain possesses and summarize the effects of drugs and training on the plast icity of the visual system. As this conference demonstrated, the visual sys tem is able to respond in many ways in an adaptive manner to lesions inflic ted early in life and in adulthood. These changes may bring about spontaneo us recovery of visual functions as long as the brain contains a sufficient capacity of residual vision. Both in children and in adults, systematic vis ual training can help patients to regain some visual functions which have p reviously been considered to be irrevocably lost. By carefully assessing re sidual vision it is proposed that the potential for plasticity of the visua l system can be utilized to achieve clinical improvement using appropriate training paradigms.