The phenomenon of memory is the prime behavioral evidence of information storage in brain cells. Other evidence is provided by the phenomenon of secondary epileptogenesis or mirror focus. In both cases the process of "remembering" has an electrophysiological correlate in the form of a particular configuration of slow waves derived from the active neuronal population. In the case of behavioral learning the correlate is a computer-derived waveform (evoked potential); in epileptogenesis it is the highly distinctive "epileptic spike". In neither case do we know the nature of the neural elements or their organization which generates the potential. Using multiunit recording techniques and computer analysis of relationships between unit discharge patterns and slow wave components, this research attempts to specify, first at an electrophysiological level, then at an anatomical and ultrastructural level and finally at a biochemical level, the individual cells and their organization which form the substrate of enduring memory. Experiments will employ cats and frogs and will utilize a classical conditioning paradigm in paralyzed animals as well as the kindling technique for establishment of secondary epileptogenesis. Once the cells have been identified electrophysiologically, intracellular dye techniques will be employed for electron microscopic identification of cell type, connectivity and synaptic organization.