Hypothetical concepts are presented in relation to the possibility of renewing memory on reconsolidation and various pathways of influencing it.
The entorhinal cortex, on the other hand, gives evidence of temporally graded changes extending up to 20 years, suggesting that it is this region that participates in memory consolidation over decades.
The entorhinal cortex is damaged in the early stages of Alzheimer’s disease.
The hypothesis that new memories consolidate slowly over time was proposed 100 years ago, and continues to guide memory research.
In modern consolidation theory, it is assumed that new memories are initially 'labile' and sensitive to disruption before undergoing a series of processes (e.g., glutamate release, protein synthesis, neural growth and rearrangement) that render the memory representations progressively more stable.
It has been assumed that once this occurs, the memory is "fixed" — a permanent, unchanging, representation.
With new techniques, it has indeed become possible to observe these changes (you can see videos here).
Researchers found that the changes to a cell that occurred in response to an initial stimulation lasted some three to five minutes and disappeared within five to 10 minutes.
If the cell was stimulated four times over the course of an hour, however, the synapse would actually split and new synapses would form, producing a (presumably) permanent change.
It is reasonable, and useful, to distinguish between: I think that "reconsolidation" is a retrieval process rather than part of the encoding processes, but of course, if you admit retrieval as involving a return to the active state and a modification of the original representation in line with new associations, then the differences between retrieval and encoding become less evident.