Memory Reconsolidation and Extinction Have Distinct Temporal and Biochemical Signatures

TLDR

Memory retrieval activates processes that can reinforce or alter stored information, initiating a reconsolidation cascade that depends on protein synthesis. The study shows that reconsolidation is faster for younger, weaker memories and that blocking CB1 or L‑type Ca channels inhibits extinction but leaves reconsolidation intact, revealing distinct biochemical pathways.

Abstract

Memory retrieval is not a passive phenomenon. Instead, it triggers a number of processes that either reinforce or alter stored information. Retrieval is thought to activate a second memory consolidation cascade (reconsolidation) that requires protein synthesis. Here, we show that the temporal dynamics of memory reconsolidation are dependent on the strength and age of the memory, such that younger and weaker memories are more easily reconsolidated than older and stronger memories. We also report that reconsolidation and extinction, two opposing processes triggered by memory retrieval, have distinct biochemical signatures: pharmacological antagonism of either cannabinoid receptor 1 or L-type voltage-gated calcium channels blocks extinction but not reconsolidation. These studies demonstrate the dynamic nature of memory processing after retrieval and represent a first step toward a molecular dissection of underlying mechanisms.