Re-stepping into the same river: competition problem rather than a reconsolidation failure in an established motor skill

Ella Gabitov,Geneviève Albouy,Bradley R King,Leonardo G Cohen,Nitzan Censor,Avi Karni,Stuart M Fogel,Arnaud Boutin,Habib Benali,Julie Carrier,Basile Pinsard,Julien Doyon

doi:10.1038/s41598-017-09677-1

Abstract

Animal models suggest that consolidated memories return to their labile state when reactivated and need to be restabilized through reconsolidation processes to persist. Consistent with this notion, post-reactivation pharmacological protein synthesis blockage results in mnemonic failure in hippocampus-dependent memories. It has been proposed that, in humans, post-reactivation experience with a competitive task can also interfere with memory restabilization. However, several studies failed to induce performance deficit implementing this approach. Moreover, even upon effective post-reactivation interference, hindered performance may rapidly recover, raising the possibility of a retrieval rather than a storage deficit. Here, to address these issues in procedural memory domain, we used new learning to interfere with restabilization of motor memory acquired through training on a sequence of finger movements. Only immediate post-reactivation interference was associated with the loss of post-training delayed gains in performance, a hallmark of motor sequence memory consolidation. We also demonstrate that such performance deficit more likely indicates a genuine memory impairment rather than a retrieval failure. However, the reconsolidation view on a reactivation-induced plasticity is not supported. Instead, our results are in line with the integration model according to which new knowledge acquired during the interfering experience, is integrated through its consolidation creating memory competition.

Highlights

Animal models suggest that consolidated memories return to their labile state when reactivated and need to be restabilized through reconsolidation processes to persist
As protein synthesis inhibitors cannot be administered to humans, the introduction of a competing task, that has been shown to effectively block the consolidation process initiated by a novel learning experience[9,10,11], has been adopted as a post-retrieval intervention in investigations of reconsolidation processes with human participants[9, 12,13,14,15]
To limit the period of memory trace reactivation as recommended by de Beukelaar et al.[15], and to minimize the effects of the additional practice afforded in the retesting per se, performance level at each time-point of interest was evaluated using data from a single block corresponding to the execution of 12 consecutive 5-element sequences

Summary

Introduction

Animal models suggest that consolidated memories return to their labile state when reactivated and need to be restabilized through reconsolidation processes to persist. Even upon effective postreactivation interference, hindered performance may rapidly recover, raising the possibility of a retrieval rather than a storage deficit To address these issues in procedural memory domain, we used new learning to interfere with restabilization of motor memory acquired through training on a sequence of finger movements. Most of the support for this idea comes from an amnesic phenomenon observed in animals using injection of protein synthesis inhibitors directly into specific brain areas in close temporal proximity to the reactivation of an established memory trace that hinders its restabilization Even such direct intervention may result only in transient impairments. Whether, when and how a competing behavioral experience following the retrieval/reactivation of a given skill can interfere with reconsolidation processes and degrade the pre-established “how to” knowledge remains an open question

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Conclusion