Introduction: The mammalian hippocampal formation is comprised of the hippocampus proper, entorhinal cortex (EC) and subicular complex (subiculum, presubiculum, parasubiculum). The EC and subicular complex process and transmit information between the neocortex and hippocampus. The electrophysiology of EC and subiculum has received little attention, despite their importance in memory formation and involvement in pathophysiological changes associated with dementia and epilepsy. Experimental Outline: The production and regulation of neuronal responses in the subiculum of the mammalian brain will be determined. Recordings will be made from anaesthetized rats. Stimuli will activate the EC and hippocampal CAI inputs to subiculum. Intracellular, extracellular and laminar recording protocols will determine the steady-state responses, neuropharmacology and functional plasticity of these projection systems when activated either singly or in concert. Resultant data will provide important insights into the functions of the subicular complex as the final stage of hippocampal processing and help clarify its role as the interface between the hippocampal formation and the neocortex.