Long-lasting hippocampal plasticity: cellular model for memory consolidation?

Abstract

The concept of memory consolidation was introduced into the scientific discourse over a century ago (Muller and Pilzecker 1900). Consolidation in its most general meaning refers to the idea that recently formed memories can sometimes be subject to stabilization over time, rendering them less susceptible to disruption by both new information and brain dysfunction. This process of maturation and stabilization manifests itself at different levels of neuronal organization and at multiple time windows. It is methodologically useful to distinguish between local, cellular consolidation and system consolidation (for review, see Dudai 1996). The first refers to processes that take place locally, in individual nodes of a neuronal circuit, i.e., synapses and neurons, during the first hours after learning. The second refers to processes that occur at the circuit level, may involve progressive reorganization of memory traces throughout the brain, and in some cases last weeks or longer. In the simplest of circuits, cellular and system consolidation may be isomorphic. In more complex circuits, system consolidation may involve additional mechanisms which reflect the selective activity of different circuits; a consequence of this selectivity is the potential, after consolidation, to retrieve memory using circuits that are different from those encoding the memory at an earlier stage (Shadmehr and Holcomb 1997; Squire and Zola 1998).KeywordsNMDA ReceptorDentate GyrusMemory ConsolidationPerforant PathSynaptic EfficacyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.