Consolidation, Reconsolidation of Memory, Extinction and Forgetting: a Review

Introduction. To study the regularities of formation of individual experience we summarize the results of research in consolidation, reconsolidation of memory, extinction and forgetting within a unified idea that considers them in the frames of systems psychophysiology as manifestations of two coordinated processes: formation of new experience and modification of previously formed experience. Theoretical Justification. Within the framework of the theory of functional systems, it had been proposed that systemogenesis also takes place in adults, since the formation of a new behavioral act is the formation of a new system. In studies with single-neuron activity recording it was shown that during performance of new behavior the simultaneous activation of multiple earlier formed systems occurs along with activation of new systems formed during learning. Therefore, we consider consolidation, reconsolidation, extinction, and forgetting as manifestations of reorganization of individual experience as a whole. The results of research in the neurophysiology of memory show that the processes of memory formation (including its consolidation) and forgetting are not mutually exclusive and can take place independently. Some forms of forgetting are caused by the inability to use memory, rather than by its removal, that makes forgetting similar to the formation of extinction. Discussion. We argue that (re)consolidation, extinction and forgetting may be based on similar long-term changes in previously formed experience, in particular those that do not let some elements of this experience to be utilized further.