The Electrophysiology Core will provide centralized services for in vitro electrophysiological studies, including preparation of the in vitro brain slices, patch-clamp recordings, extracellular recordings, and the associated image and data processing plus analysis. Five aims in four projects will utilize this Core facility. Whole-cell patch-clamp recordings will be obtained from in vitro rat brain slices from basal forebrain neurons (Projects 2 & 3), ventrolateral preoptic (VLPO) neurons (Project 3) and from mouse tuberornarnmUlary, locus coeruleus and basal forebrain neurons (Project 5). In addition, extracellular recordings of hippocampal field potentials will be obtained from the CA1 region (Projects 2 & 4). The centralization of this resource makes the technique of in vitro electrophysiological recording available to multiple investigators in an environment that facilitates standardization of recording conditions across all projects.