9421582 Martin A major challenge facing brain researchers is to explain how signals arriving in the brain from sensory receptors is translated into commands for movement. In this grant, Dr. Martin will examine the organization of the region of the brain known as the motor cortex and its relation to the steering of forelimb movements directed toward visual targets. There appear to be functional subregions of the motor cortex, and they will be analyzed in this work by selectively, and reversibly, inactivating parts of the motor cortex as movements are made. This research will increase our understanding of the principles underlying biological motor control. This understanding should have important implications for the design of robotic control circuitry and the development of prosthetic devices. ***