On the possibility of simultaneously recording from two cells with a single microelectrode in the hippocampal slice.

Unusual cellular elements have been recorded intracellularly in the CA1 region of the rat hippocampal slice. The elements appear, by all electrophysiological criteria except one, to be glia. However, unlike glia, they can fire action potentials. We suggests that these recordings represent cases of artifactual coupling of two cells by a recording microelectrode. The results have implications for the interpretation of dye injection experiments in the hippocampal CA1 region.