It is proposed to characterize the basic neurophysiology of the aged rat brain, utilizing the hippocampus as a model system. Studies would be conducted using both in vivo (anesthetized) and in vitro (hippocampal slice) preparations. The experiments would particularly focus on aspects of synaptic plasticity (e.g., potentiation, depression) which have been speculatively linked to memory. If an age-related neurophysiological deficit is found, attempts would be made to correlate the degree of neurophysiological impairment with the degree of memory impairment along individual animals. Memory deficits have been reported to occur in the aged rats that would be employed (Strain: Fischer 344). Subsequently, if a physiological deficit can be defined, pharmacological attempts to counteract the deficit would be carried out.