To date, the relationship between anomalous ipsilateral corticofugal motor projections and functional outcome has not been examined in detail. There is preliminary evidence that the presence of these anomalous ipsilateral projections is associated with poor outcome, suggesting that they represent an inefficient cortical re-organization process. In addition, the anomalous projections that arise de novo from the ipsilateral primary motor cortex appear to have the worst prognosis. The proposed research study will characterize anomalous ipsilateral corticofugal motor projections in a group of children with spastic hemiplegia and spastic diplegia subtypes of cerebral palsy using TMS and EMG. We will evaluate functional limitations of the hand in these children and will examine the relationship between each type of ipsilateral pathway and functional outcome. In this way, it will be possible to determine which anomalous ipsilateral projections are associated with poor function in patients with cerebral palsy.