Sleep and Memory Updating

Abstract

Prior research shows that a contextual reminder can return a previously consolidated memory to an unstable state similar to initial encoding. New knowledge presented before the trace is reconsolidated can emerge as updating of the first experience with knowledge from the second. Sleep has been implicated in the long-term strengthening and storage of newly acquired episodic memories; thus, the delay-dependent emergence of intrusions may be facilitated by a delay containing sleep. The experiments described here explore this possibility by tracking sleep while participants undergo an episodic reconsolidation paradigm, which involves learning two sets of information and a recall task, all separated by 48 hours. Prior work using this paradigm shows that reminding participants of the first learning experience prior to learning the second renders them more likely to intrude information from the second set in their recall of the first. In the present study, Experiment 1 compares amount of sleep across days in order to tease apart the differential effects on consolidation of the original Set 1 memory and its reconsolidation when it is updated with Set 2. In Experiment 2, the first analysis (Analysis A) identifies events in the sleep EEG, such as spindles, that are associated with certain elements of memory consolidation, and expands on the parameters in which they occur in memory reconsolidation in Analysis B. The overall aim of this project is to use sleep as a means to inform the nature of memory reconsolidation, which paints memory as ever changeable.