Summary

LTP does not equal memory. Rather, it is a critical component of the complicated process of memory formation. It seems to me now that I have written this chapter that the case for LTP or a similar phenomenon in memory formation is surprisingly strong! A very broad range of studies supports the hypothesis that hippocampal LTP is involved in triggering consolidation of memories in the cortex. It's important to keep in mind the subtleties of the hippocampal/cortical memory system. In addition, a second take-home message of this chapter is that hippocampal LTP need not be constrained to contributing to this single process. A powerful mechanism of activity-dependent synaptic plasticity such as LTP, particularly one that has the capacity for detecting three- or four-way coincidence events, has likely been adapted to multiple roles in the hippocampus and elsewhere in the brain. Specifically, we have discussed the likelihood that hippocampal LTP contributes to the formation of complicated associations and abstract spatial constructs, and that LTP may serve as part of a short-term memory buffer for trace associative conditioning.

In the next two chapters, we will discuss how these processes may be going awry in human learning and memory disorders, specifically human mental retardation syndromes and Alzheimer's disease.

Recent work in these areas has made clear the importance of understanding the molecular basis of LTP and memory formation in the biomedical realm. Far from being esoteric investigations into the minutia of synaptic plasticity, studies of LTP and the molecular basis of memory are giving important insights of great relevance to the human condition.

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Kelly Rampon

Mental Retardation Syndromes J. David Sweatt, Acrylic on canvas, 2002

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