Although the physical damage caused by stroke is irreversible, the brain has an impressive capacity for spontaneous functional recovery. After a stroke surviving brain cells will assume roles previously performed by stroke-affected cells. This plasticity appears to be necessary for recovery of function after severe injuries, but it may not be entirely beneficial. When surviving brain regions are forced to compensate for a loss of neural circuitry, this new duty could impair their ability to carry out their original function.
Stroke recovery is a slow process, and is best studied in longitudinal experiments. In the motor cortex, the brain region responsible for voluntary movement, such experiments have been constrained by the limitations of electrical brain stimulation. My colleagues and I recently developed a novel technique that makes such experiments possible for the first time. By repeatedly mapping the motor cortex of mice before and after a targeted stroke, we are able to study the brain’s response to injury on an unprecedented time scale.