Long-Term Consequences of Early Eye Enucleation on Audiovisual Processing

A growing body of research shows that complete deprivation of the visual system from the loss of both eyes early in life results in changes in the remaining senses. Is the adaptive plasticity observed in the remaining intact senses also found in response to partial sensory deprivation specifically, the loss of one eye early in life? My dissertation examines evidence of adaptive plasticity following the loss of one eye (unilateral enucleation) early in life. Unilateral eye enucleation is a unique model for examining the consequences of the loss of binocularity since the brain is completely deprived of all visual input from that eye. My dissertation expands our understanding of the long-term effects of losing one eye early in life on the development of audiovisual processing both behaviourally and in terms of the underlying neural representation. The over-arching goal is to better understand neural plasticity as a result of sensory deprivation. To achieve this I conducted seven experiments, divided into 5 experimental chapters, that focus on the behavioural and structural correlates of audiovisual perception in a unique group of adults who lost one eye in the first few years of life. Behavioural data (Chapters II-V) in conjunction with neuroimaging data (Chapter VI) relate structure and function of the auditory, visual and audiovisual systems in this rare patient group allowing a more refined understanding of cross sensory effects of early sensory deprivation. This information contributes to us better understanding how audiovisual information is experienced by people with one eye. This group can be used as a model to learn how to accommodate and maintain the health of less extreme forms of visual deprivation and to promote overall long-term visual health.