Research in my laboratory combines a variety of fluorescent probe technologies with confocal microscopy to visualize the dynamic behavior of growth cones and assess their physiological responses during axon extension in vitro and guided outgrowth in the intact spinal cord. Molecular expression as well as photolytic uncaging techniques are used to alter the physiology of growth cones. By combining the latest advances in imaging technologies with improved optical probes including fluorescent fusion proteins and FRET-based reporter molecules we hope to answer the following questions: 1) What role does intracellular calcium and cAMP play in the regulation axon outgrowth by specific classes of neurons at choice points in the developing spinal cord? 2) How do changes in cytosolic calcium and cAMP over varying spatial and temporal dimensions affect the growth cone cytoskeleton; 3) How do downstream effectors such as the Rho GTPases, Arp 2/3, Ena/VASP proteins and other cytoskeletal regulatory factors control growth cone behavior in response to specific guidance factors?