Synaptically identified hippocampal slow potentials during behavior.

Averaged evoked slow-wave potentials (AEPs) were recorded from various locations within the dentate gyrus and CA1 field of the hippocampus of 16 rats during the performance of an operant tone discrimination task. Consistent time-locked tone averaged evoked potentials (AEPs) were recorded from the perforant path zone in the outer molecular layer of the dentate gyrus. Tone AEPs were never present in this region (1) prior to development of the discrimination, (2) during behavioral extinction, or (3) during the performance of other operant behaviors. Results are discussed in terms of the functions of the perforant path in neural and behavioral plasticity.