Poster D91, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Mechanisms of targeted memory reactivation during sleep
James Antony1, Luis Piloto1, Margaret Wang1, Ken Norman1, Ken Paller2; 1Princeton University, 2Northwestern University
Newly formed hippocampal memory traces become reactivated during sleep, suggesting sleep may play an active role in long-term memory stability. Memory reactivation can be induced during post-learning sleep by presenting stimuli that had previously been associated with learning. This method, termed targeted memory reactivation (TMR), offers a unique opportunity to study the physiological conditions underlying memory reactivation with high temporal precision. In two experiments, participants learned specific sound-picture pairs followed by spatial locations for those pictures against a background grid. Next, they took a pre-nap location test and napped in the lab. During online indications of slow-wave sleep, half of the sounds were softly and repeatedly presented. At a post-nap test, cueing benefited memory. Moreover, we found that sleep spindles — bursts of 11-16 Hz electroencephalographic activity thought to contribute to memory processing — increase shortly after presenting TMR sound cues and predict later memory retention. However, spindles have a refractory period with a median of about 6 seconds, suggesting cues may not always be able to induce spindles. Indeed, we found spindles occurring shortly before (< 2.5 s) TMR cues prevent the TMR-related spindle increase and negatively predict later memory retention. To test causality of this later finding, we will discuss results from a study that tracks spindles in real time and delivers TMR cues either shortly after or long after spindles. These findings significantly contribute to understanding the efficacy of TMR and memory reactivation more generally.
Topic Area: LONG-TERM MEMORY: Episodic