Poster F88, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Sleep relates to the pattern representation and behavioral stability of memories
Emily Cowan1, Anli Liu2, Sanjeev Kothare2, Orrin Devinsky2, Lila Davachi1; 1New York University, 2NYU Langone School of Medicine
Sleep has been linked with successful memory consolidation, and evidence suggests particular features in the architecture of sleep may relate to sleep-dependent memory enhancements. Recent evidence has shown greater distribution of memory traces after a 24-hour delay, as measured by functional connectivity, is predictive of subsequent resistance to forgetting, indicating a specific role in memory stabilization. However, it remains unknown what aspects of sleep architecture are related to changes in the representation of memory traces, and the effect on subsequent behavioral measures of memory. To investigate this relationship, we designed a three-day experiment utilizing overnight polysomnography recordings, fMRI, and behavior. Subjects encoded lists of word-image pairs twice, either with an intervening period of overnight sleep (Sleep List), or a brief wakeful period (New List), such that the lists differed the opportunity for potential consolidation. During the re-study session, subjects were presented with the previously seen word-image pairs, and a new list of pairs (Single Study List) while in the scanner. Cued source recall was probed immediately following the scan and after a 24-hour delay, providing a measure of memory stability over time. Using a multivariate pattern similarity analysis, we examined the representations of the trials from each encoding list. Pattern separation was greater for subsequently remembered, compared to forgotten, pairs in the right hippocampus only in the Sleep List. By contrast, those trials showed more similar patterns in cortical regions. Additional analyses will focus on relating oscillatory signals during sleep with the neural patterns and behavioral expression of these memories.
Topic Area: LONG-TERM MEMORY: Episodic