This project studies neural mechanisms underlying processing of cognitive information and the learning of motor adaptations associated with spatial-motor behavior. Single unit activity is measured in monkeys trained to perform multidirectional reaching movements during instructed- delay tasks. The frontal lobe is an important structure for the generation of (a) reaching behavior in extrapersonal space, (b) proper movement sequencing, and (c) the utilization of requisite information from memory and sensory systems for guided movements. This is a behavioral neurophysiology study of three major divisions of the frontal lobe of primates: the primary motor cortex (M1), dorsal premotor cortex (Pmd), and supplementary motor area (SMA). Two paradigms involving the serial presentation of spatial information are used to investigate each cortical area and the processing of requisite visual-spatial information for reaching. In one a previously learned movement sequence is prepared and executed by a monkey. This task will determine which specific attributes of spatial reaching are encoded at the cortical level and whether movement sequences are represented in neural signals as transformation between spatial representations off component movement segments, or, as representations of the relationship between the first and second movement segments. In the second task, a robot arm is used to rapidly change the mechanical environment of reaching movements and accordingly modify the sensorimotor experience of producing different reaching movements with the same starting and final arm positions. The robot arm will rapidly produce unfamiliar mechanical environments and simulate collisions between the arm and "virtual" objects at specific locations along the movement trajectory. This design will allow the neural correlates of learned adaption of spatial-motor behavior to be studied.