Posttraining changes in excitability of the commissural path-CA1 pyramidal cell synapse in the hippocampus of mice

Mice were partially trained on a bar-press operant conditioning task on continuous reinforcement (CRF). The amplitude of population excitatory postsynaptic potentials (EPSPs) evoked by commissural stimulation of the Ca2 field of the dorsal hippocampus was found to significantly increase 1 h after training and then to decrease. This phenomenon was either not observed or much less evident in mice could not learn the task or which had already been trained on this task.