Here's a wonderful example of brain plasticity. When infants or toddlers suffer massive trauma in one cerebral hemisphere, the brain will typically "reroute" the interneural connections in the surviving motor cortex so that the child will recover motor control of both the left and right sides of the body. Even with something as basic as motor function, there is not a specific area of the left or right motor cortex that is rigidly "hardwired" to control a specific part of the body.
Miles