Poster B98, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Elucidating Neural Correlates of Olfactory Targeted Memory Reactivation in the Sleeping Human Brain
Laura Shanahan1, Eva Gjorgieva1, Jay Gottfried1,2; 1Northwestern University Feinberg School of Medicine, 2Northwestern University Weinberg College of Arts and Sciences
Odors have been shown to be key agents in targeted memory reactivation (TMR), a technique used to manipulate sleep-based memory consolidation. During olfactory TMR, an odor is presented during learning, and then again during subsequent sleep (i.e., reactivation). TMR often results in enhanced performance for the associated memory task upon waking, but the neural mechanism underpinning these memory improvements is not well understood. Researchers speculate that reactivation cues bias memory replay toward associated memories. Here, we developed a novel olfactory TMR paradigm to test the hypothesis that odors evoke replay of associated memories in the sleeping human brain. First, subjects learn the locations of pictures belonging to specific categories during fMRI scanning. Next, subjects learn to associate each picture category with a unique odor. Then, half of the category-specific odors are presented in sleep during simultaneous EEG-fMRI recording. Our behavioral data suggests that reactivation improves memory performance for reactivated picture categories. Moreover, in an interference test following reactivation, reaction times for reactivated picture categories are increased, possibly reflecting a struggle to override the strengthened memory traces. Finally, we employ multivariate pattern classification of fMRI data to show that category-specific pictures elicit distinct ensemble patterns of neural activity during learning. In future analysis, we plan to directly test the hypothesis that odors promote replay of reactivated memory traces by searching for the re-emergence of category-specific fMRI activity during the reactivation phase.
Topic Area: LONG-TERM MEMORY: Episodic