Advances in cognitive neuroscience and brain imaging technologies provide us with the increasing ability to interface directly with activity in the brain. Researchers have begun to use these technologies to build brain-computer interfaces. In these interfaces, humans intentionally manipulate their brain activity in order to directly control a computer or physical prostheses. The ability to communicate and control devices with thought alone has especially high impact for individuals with reduced capabilities for muscular response. In fact, applications for patients with severe motor disabilities have been the driving force of most brain-computer interface research.