Linking New Information to a Reactivated Memory Requires Consolidation and Not Reconsolidation Mechanisms

TL;DR

The study shows that linking new information to a reactivated memory happens through consolidation, not reconsolidation, which was previously thought to be responsible.

Contribution

The study reveals that consolidation, not reconsolidation, is the mechanism that links new information to a reactivated memory.

Findings

Reconsolidation does not contribute to linking new information with reactivated memories.

Consolidation mechanisms are responsible for associating new information with reactivated memories.

The original memory remains intact during this process.

Abstract

A new memory is initially labile and becomes stabilized through a process of consolidation, which depends on gene expression. Stable memories, however, can again become labile if reactivated by recall and require another phase of protein synthesis in order to be maintained. This process is known as reconsolidation. The functional significance of the labile phase of reconsolidation is unknown; one hypothesis proposes that it is required to link new information with reactivated memories. Reconsolidation is distinct from the initial consolidation, and one distinction is that the requirement for specific proteins or general protein synthesis during the two processes occurs in different brain areas. Here, we identified an anatomically distinctive molecular requirement that doubly dissociates consolidation from reconsolidation of an inhibitory avoidance memory. We then used this requirement to investigate whether reconsolidation and consolidation are involved in linking new information with reactivated memories. In contrast to what the hypothesis predicted, we found that reconsolidation does not contribute to the formation of an association between new and reactivated information. Instead, it recruits mechanisms similar to those underlying consolidation of a new memory. Thus, linking new information to a reactivated memory is mediated by consolidation and not reconsolidation mechanisms.

The association of new information with an established memory is mediated through a consolidation mechanism, leaving the original memory intact.

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