Intracellular recordings were made from CA1 pyramidal cells in the hippocampal in vitro slice preparation. Neurons displayed characteristics previously described for the intact preparation including: EPSPs, IPSPs, depolarizing after-potentials, bursting, frequency potentiation, double pulse facilitation, and probably dendritis spiking. Cells could be discharged when orthodromic or antidromic pathways were stimulated, with injection of a depolarizing current pulse, and from iontophoresis of glutamic acid. The apparently normal behavior of the neurons makes the isolated hippocampal slice a promising cortical preparation.