Initial encoding strength determines the effectiveness of targeted memory reactivation with odor cues

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Gautam Narayan¹ (narayag1@uci.edu), George Babineaux III², Matthew Cho¹, Sandhya Murugavel¹, Tiange Lu¹, Nicholas J. Lew¹, Sarvia Aquino¹, Eitan Schechtman¹; ¹Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine, California, USA, ²College of Science and Technology, North Carolina Agricultural and Technical State University, Greensboro, North Carolina, USA

Sleep plays an active role in the consolidation of memories that were encoded during the day. Targeted memory reactivation is a technique that uses non-invasive sensory cues, such as odors, to preferentially reactivate associated memories during sleep. In a pioneering study, Rasch et al. (2007) showed that odor reactivation during sleep improved memory for all learned items in a spatial task. Since the design included only one odor and a single learning block, it remains unclear whether the odor cues benefited consolidation of the learning context as a whole or selectively targeted the learned associations. We used a within-subjects design to test whether the presentation of odor cues during sleep would selectively prioritize consolidation for one category of objects over another. Participants (N=32) were trained on a 2D object location task, where each category was paired with a distinct odor, before taking a pre-nap test. During non-REM sleep, participants were re-exposed to one of the odors. After their nap, participants completed a test of the object locations. Our results showed a benefit of cueing, but only when accounting for pre-sleep memory performance. Cueing benefited memory uniformly, but this benefit was stronger for weakly encoded memories. These results provide a conceptual replication of Rasch et al. (2007), suggesting that odor-cueing can be used to selectively reactivate sets of memories with a task rather than the learning context as a whole. Moreover, our results provide more evidence that initial encoding strength dictates the extent of reactivation effectiveness.

Topic Area: LONG-TERM MEMORY: Episodic