Abstract

Consolidated memories can persist from a single day to years, and persistence is improved by retraining or retrieval-mediated plasticity. Memory enhancement has a fundamental role in the maintenance of memory relevance. One retrieval-based way to strengthen memory is the reconsolidation process. This mechanism occurs when a consolidated memory is reactivated by the presentation of a reminder which represents an incongruence between past and current events, generating an error in the prediction. In humans, it was shown that the presentation of more than one of these reminders improves the performance in the testing session by enhancing memory precision. Here, we tried to make a step forward in the identification of brain correlates imprinted during the reconsolidation process of a syllable-paired association task after the reactivation. We suggest that the brain at rest is a potential gateway to understand the brain plasticity that is occurring during the memory enhancement. The aim of this study was to anlayze the power spectra and EEG connectivity of the resting state immidiatly after the three different reactivation conditions: the presentation of one cue that included the prediction error and triggered the labilization-restabilization process (Rx), the presentation of two consecutive Rx (Rx2) and the presentation of a reminder that not labilized the original trace. The reminders that triggered the reconsolidation process were associated with an increase in whole brain theta and low beta band. Moreover, the condition that involved the double reactivation performed better in the testing session 48 hours after training and presented the highest theta power (between 4 and 8 Hz) in frontal regions as in encoding and retrieval of episodic memory tasks. In addition, the Rx2 condition present an increase of all oscillation bands in the whole brain wich supports previous findings where the retrieval of memories that passed through the reconsolidation process are associated with a larger and more connected brain network, involving a better exchange information.