Grant: Doctoral: Vanier Canada Graduate Scholarships

Stroke is the leading cause of adult disability. Although the physical damage is irreversible, many deficits seen immediately after a stroke disappear in the following weeks. This spontaneous recovery is partly due a to rewiring of the brain's circuitry. My research will reveal plasticity in the brain during the period of spontaneous recovery after stroke, from the level of brain regions down to single neurons. I plan to study these phenomena in the sensory-motor cortex of mice, which is the brain region that processes sensory information from the limbs and controls their movement. Traditionally, making maps of the motor cortex has been labour-intensive and damaging to the brain. This is because the process required the insertion of an electrode into dozens of points in the brain, then passing an electrical current at each point to elicit movement of the different body parts. In order to accelerate this process, we have developed a novel approach that makes use of transgenic mice possessing light-activated neurons. Instead of inserting an electrode into the brain, a laser beam is scanned across the brain surface while motion sensors automatically record resulting limb movements. This technique is hundreds of times faster than previous methods, and can be repeated in the same mouse for months. I plan to use our new light-based mapping method to monitor the organization of the sensory-motor cortex before and after stroke, an experiment that would not be possible without this technical advance. Although few therapeutic options are currently available for patients recovering from stroke, enhancement or modification the brain's natural repair processes represents a logical target for new treatments. With a better understanding of stroke-induced plasticity, it may be possible to identify those natural mechanisms of recovery that are most beneficial, and to screen drugs or therapies for the ability to facilitate these biological processes.