This is a RUI proposal to involve undergraduate engineering students in neurophysiology research. The project is to record from cells of the hippocampus of freely-moving rats during the preweaning and postweaning periods. The responses to paired electrical stimulation will be used to characterize the development of facilitatory and inhibitory modulation of the studied cells. The proposed project is unique in that neurophysiological correlates of behavior can be obtained by the use of unanesthetized and freely moving animals. The research will lead to an improved understanding of the basic physiology of maturation, and it will also involve engineering undergraduates in significant life sciences research.