Footshock-induced modification of a monosynaptic evoked potential in the hippocampus.

Parameters of dentate gyrus field potentials evoked by stimulation of the perforant path were studied in freely moving rats before and after repeated footshock application. An increase of population-EPSP steepness and a shortening of population spike latency was demonstrated immediately after the footshocks. These results indicate control for variables in behavior should be included in studies of monosynaptic potentials.