This study demonstrates the transfer of both motor and sensory functions from one hemisphere to the other in children who had an entire cortical hemisphere surgically removed. The areas of the cortex responsible for these new functions in the remaining hemisphere are associative motor and sensory areas and do not include the typical primary motor and somatosensory regions, thus suggesting the regionalization of brain plasticity. This regionalization can be evaluated with functional magnetic resonance imaging, supporting this technique as an effective tool in the study of brain plasticity.