This proposal requests funds for the purchase of a computer- aided system for the reconstruction, measurement and statistical analysis of neuronal processes from sectioned or whole-mounted nervous tissue. The central goal of all the projects described is to understand how the detailed structure of neurons and their anatomical relationship?s with one another translate into the precise functioning of the nervous system. Five of the major users have projects that utilize various aspects of the insect nervous system as test subjects, a sixth investigates neural development in the amphibian nervous system.