Grant: Joint Canada-Israel Health Research Program

Following stroke or traumatic brain injury, many patients exhibit cortical visual impairment (CVI), usually in the form of a large blind spot in the visual field contralateral to the insult. CVI results specifically from damage to the primary visual cortex, and it is usually permanent. However, these patients do have access to visual input, via another brain pathway that bypasses the primary visual cortex. Animal studies have shown that this pathway is functionally intact following brain damage, but it appears that CVI patients are unable to use them. An exciting but controversial idea is that training can strengthen this residual pathway. Indeed, some studies have shown that CVI patients can be trained to react to visual stimuli presented in their blind fields. However, other studies have not detected any benefit of training. Recent work in our laboratories has led to the development of new training protocols that appear to powerfully shape the way that subjects perceive visual stimuli. Our goals in this project are therefore to discover even more effective ways to engage the brain's potential for plasticity and to design and to test new vision training protocols, based on our expanding knowledge about the brain's visual pathways. We will design software programs that maximally stimulate residual pathways in CVI patients and that can be used easily and conveniently in a home setting. We will then determine the extent to which vision can be recovered following stroke. The training framework we hope to establish could be extended to pediatric patients and to healthy subjects who want to improve specific aspects of their visual perception.