SUMMARY

This chapter begins with a brief discussion of the complexity of the long-term potentiation (LTP)-memory debate. We suggest that the notion of LTP as a unitary “memory encoding device” is too simplistic to survive rigorous experimentation and debate. However, while there are difficulties in making the direct connection between LTP and memory, we have not abandoned the proposition that LTP studies can enhance our understanding of the physiology of memory. The primary focus of this chapter is to incorporate studies on LTP, memory, and stress into a synthesis on the dynamics of emotional memory storage in the hippocampus and amygdala. The work is based on the idea that the induction or blockade of LTP can serve as a “diagnostic” measure of how stress affects information processing by different brain structures. The synthesis provides a novel perspective on why the characteristics of nonemotional memories differ from the pathologically intense, and fragmented, characteristics of traumatic memories.

Introduction

Long-term potentiation (LTP) has long been embraced as a model of memory because its characteristics are consistent with models of synaptic storage mechanisms and it has features in common with learning and memory. Just as memory is a lasting trace formed as a result of a brief experience, LTP is a lasting enhancement of synaptic efficacy produced by brief electrical stimulation. Initially, the field was buoyed by repeated findings of commonalities between LTP and memory. The early work showed, for example, that drugs that blocked hippocampal LTP impaired hippocampal-dependent learning, and that LTP, as with memory, was impaired in old animals.