How do we construct maps of the real world in our brain? Apparently there is a structure called the hippocampus that contains a spatial map that is laid down through experience. Dr. Walsh has devised a novel behavioral test to assess how various chemical inputs affect the behavioral function of this structure. With this NSF grant he will manipulate the chemical environment of the cells that provide major inputs to the hippocampus. By measuring the number and types of errors made in a spatial maze after each manipulation he will be able to determine whether his chemical manipulations have improved or interfered with hippocampal function. The results of these experiments will improve our understanding of the neurobiological foundations of learning and memory. The future applications will include drugs that can be used to improve memory or, alternatively, reduce the influence of unwanted, intrusive memories.***//