Memory consolidation

Memory consolidation is the process by which the brain stabilizes newly learned information so that it can be stored long-term. A memory trace is the biological change in neural circuits that occurs during learning. Consolidation is divided into synaptic consolidation, which occurs within the first hours of learning at individual synapses and is supported by late-phase long-term potentiation, and systems consolidation, which involves gradual reorganisation over weeks to years with reduced reliance on the hippocampus and greater involvement of cortical networks. A third process, reconsolidation, has been proposed, in which consolidated memories become unstable again after retrieval and may need to be updated before being stabilised once more. The idea was formally introduced in the late nineteenth century by the German researchers Georg Elias Müller and Alfons Pilzecker, who proposed that memory takes time to fixate and stabilise, and later studies of anterograde amnesia, including the case of patient H.M., helped establish the modern theories of consolidation.