Beta and alpha desynchronizations underlie reconsolidation-mediated episodic memory updating

Abstract

Reactivation returns a consolidated memory to a plastic state, opening a window for the existing memory to be updated. For episodic memory, learning of competing information upon reactivation either integrates the new information into the reactivated memory or disrupts the reactivated memory directly, but the two effects were found in distinct experimental paradigms and their neural mechanisms are largely unknown. The current study explored the effects and neural mechanisms of episodic memory reactivation using behavioural and MEG techniques. Taking advantage of an independent-cue retrieval procedure, we revealed both the integration and the forgetting effects by a single post-reactivation interference paradigm. However, while the integration effect followed the reconsolidation window, the forgetting effect did not, suggesting only the integration effect being caused by memory reconsolidation. MEG measurements further revealed beta-band power decrease during reactivation and alpha-band power decrease during post-reactivation interference, both of which parametrically predicted the degree of memory integration. But neither the beta nor the alpha desynchronization was related to the forgetting of the original memory. Our results suggest original memory forgetting and new information integration happen in different time periods after memory reactivation, and beta and alpha desynchronizations underlie reconsolidation-mediated episodic memory updating.