The Neurobiology of Consolidations, Or, How Stable is the Engram?Yadin Dudai|Annual Review of Psychology|2004 Consolidation is the progressive postacquisition stabilization of long-term memory. The term is commonly used to refer to two types of processes: synaptic consolidation, which is accomplished within the first minutes to hours after learning and occurs in all memory systems studied so far; and system consolidation, which takes much longer, and in which memories that are initially dependent upon the hippocampus undergo reorganization and may become hippocampal-independent. The textbook account of consolidation is that for any item in memory, consolidation starts and ends just once. Recently, a heated debate has been revitalized on whether this is indeed the case, or, alternatively, whether memories become labile and must undergo some form of renewed consolidation every time they are activated. This debate focuses attention on fundamental issues concerning the nature of the memory trace, its maturation, persistence, retrievability, and modifiability.
The Molecular and Systems Biology of MemoryThe Consolidation and Transformation of MemoryThe Restless Engram: Consolidations Never EndYadin Dudai|Annual Review of Neuroscience|2012 Memory consolidation is the hypothetical process in which an item in memory is transformed into a long-term form. It is commonly addressed at two complementary levels of description and analysis: the cellular/synaptic level (synaptic consolidation) and the brain systems level (systems consolidation). This article focuses on selected recent advances in consolidation research, including the reconsolidation of long-term memory items, the brain mechanisms of transformation of the content and of cue-dependency of memory items over time, as well as the role of rest and sleep in consolidating and shaping memories. Taken together, the picture that emerges is of dynamic engrams that are formed, modified, and remodified over time at the systems level by using synaptic consolidation mechanisms as subroutines. This implies that, contrary to interpretations that have dominated neuroscience for a while, but similar to long-standing cognitive concepts, consolidation of at least some items in long-term memory may never really come to an end.
dunce, a mutant of Drosophila deficient in learning.Yadin Dudai, Yuh Nung Jan, David M. Byers et al.|Proceedings of the National Academy of Sciences|1976 Normal Drosophilia learn to avoid an odorant associated with electric shock. An X-linked mutant, dunce, has been isolated that fails to display this learning in spite of being able to sense the odorant and electric shock and showing essentially normal behavior in other respects.