The subiculum to entorhinal cortex projection is capable of sustaining both short- and long-term plastic changes

The hippocampus communicates with the neocortex via the entorhinal cortex. These areas are thought to be critically involved in the consolidation of memories. The hippocampus is considered to be the site of association of sensory information, which is then laid down for long-term storage in the neocortex. We examined the projection from the subiculum to the entorhinal cortex to determine whether it could function to transfer this hippocampally-processed information to the neocortex. Following stimulation in the subiculum we demonstrate a negative-going deflection followed by a positive-going deflection in the entorhinal cortex. This projection is capable of short-term plastic changes in the form of PPF. FIn addition, we demonstrate that long-term synaptic changes in the form of LTP and LTD could be sustained for at least 30 min on this pathway. Finally we show that PPF changes after LTP and LTD, suggesting that a presynaptic mechanism may be involved in both of these pathways.