ABSTRACT
Memory consolidation is a neural process of information transfer from a short-term to a long-term store which results in the establishment of a permanent memory resistant to disruptive treatments (McGaugh and Herz, 1972; Weingartner and Parker, 1984; Alvarez and Squire, 1994). Though the concept of memory consolidation forms a core of current research on information storage in the nervous system, there is still no apparent consensus about the neural mechanisms of this event. This is not due to a vague definition of the process itself. On the contrary, recent advances in systems and molecular neuroscience have produced two clear models of memory consolidation (Alvarez and Squire, 1994; DeZazzo and Tully, 1995; Abel et al., 1995; Bailey et al., 1996). However these two models operate on very different scales of time and space. A network model is based mainly on the
studies of declarative memory distortions in humans and effects of brain lesions in mammals (Squire, 1992). It views consolidation as a structural reorganization of memory repository between the hippocampal system and the neocortex. Such a process requires lengthy periods of weeks and even years to be accomplished (Squire et al., 1993; Squire and Zola, 1996). The molecular genetics approach adopts a broader view of long-term memory consolidation as a universal biological phenomenon conserved through the animal kingdom and shared by different forms of nondeclarative and declarative memories (Bailey et al., 1996; Tully et al., 1994). A shift from short-term to long-term memory is understood here as a critical “switch” between mechanisms that support synaptic modifications within the same cell. This transfer of information from the short-term to long-term storage is believed to require activation of gene expression through universal transcriptional mechanisms which are conserved from invertebrates to mammals and operate within minutes to hours after learning (Abel et al., 1995; DeZazzo and Tully, 1995; Mayford et al., 1995; Tully, 1997).
