Synaptic Plasticity and Spatial Representations in the Hippocampus

Abstract

How does the brain acquire and remember new experiences? It is believed that synaptic plasticity, the process by which synaptic connections are strengthened or weakened, is a key mechanism for information storage in the central nervous system. Long-term potentiation (LTP), the long-lasting enhancement of excitatory synaptic transmission, and long-term depression (LTD), the persistent depression of synaptic responsiveness, are exp-erimental models of synaptic plasticity thought to reveal how synapses are modified during learning. In this chapter we focus on the properties of LTP and LTD that make them attractive functional models for memory and review key findings from studies that demonstrate a link between LTP and behavior. We then discuss how synaptic modifications can affect spatial representations expressed by hippocampal place cells, which have been used as tools for understanding how synaptic changes are implemented in neural networks. We conclude the chapter by discussing how attractor states in neural networks can aid in the storage and recall of many representations involving more than just space, and how LTP may help fine-tune shifts between attractor states during behavior.