The long-range goal of the proposed project is to clarify the organization of projections from field CAI of the hippocampus. To accomplish this goal, three specific groups of experiments in the rat are proposed: 1) A detailed study of axonal projections from field CAI to the lateral septal complex, to the subiculum, and to the entorhinal area using the anterograde tracer, PHAL; 2) A study of neural inputs to field CAI using the retrograde tracer, fluorogold; 3) An analysis of the topographic organization of projections along the septotemporal axis of the hippocampus. A better understanding of the circuitry in which field CA 1 is involved and the organization of these projections will lead to a better understanding of the hippocampus as a whole and how it interacts with other systems to control goal-directed behavior. Such understanding will eventually lead to breakthroughs in the treatment of certain disorders related to aging, diseases, and trauma.