Grant: Operating Grant

Vision is a powerful source of information to control locomotion. We have previously shown that persons with stroke have an altered processing of visual motion information (optic flow) to control their speed and direction of walking. It remains unclear if such altered walking behaviours are caused by difficulties in discriminating visual motion or in integrating multiple sources of sensory and motor information during gait. Whether the expression and severity of the altered walking behaviours is explained by the brain lesion location is also unclear. We aim to understand, using functional magnetic resonance imaging (fMRI), normal brain structures that are involved in the discrimination of heading and active control of steering when exposed to optic flow. We will also investigate whether optic flow speed modifies brain activation while discriminating heading direction. The ability of stroke and healthy individuals to discriminate heading and control steering during simulated self-motion in sitting will be examined. Steering performances in sitting vs. walking will further be investigated to assess the contribution of sensorimotor deficits related to postural and gait dysunctions post stroke. Finally, we will determine whether individuals post stroke can adapt and hence learn to enhance their steering performance in response to repeated optic flow exposure. The visual control of walking is essential to safely navigate in the environment. The proposed studies will provide insights on brain functions, in particular visual perception in the control of walking after stroke. Results will also lead to the development of a virtual reality-based locomotor training protocol that incorporates manipulation of visual motion information.