Late post-learning effect of entorhinal cortex electrical stimulation persists despite destruction of the perforant path.

In an appetitive learning task in mice, stimulation of the lateral entorhinal cortex (LEC) 30 min after training produced an improvement in retention 24 h later, as well as faster extinction of conditioning. This effect persisted in animals with bilateral lesions of the perforant path. In addition, the threshold for hippocampal after-discharges produced by LEC stimulation was raised significantly in perforant-path lesioned animals. The results indicate a functional dissociation between hippocampal and cortical mechanisms involved in memory consolidation.