0108 Brief Periods of Sleep and Quiet Rest Equivalently Benefit Memory Consolidation

Abstract Introduction Past research has demonstrated that sleep benefits the consolidation of memories. However, more recent studies have suggested that quiet rest could have similar benefits for memory. Here, we examined the effect of a brief period of sleep, quiet rest, or active wakefulness on declarative and procedural memory. We hypothesized that sleep and quiet rest would equally benefit memory, compared to a period of active wakefulness. Methods After completing a declarative (Icelandic-English word pairs) and procedural memory task (the Motor Sequence Task (MST)), participants began a 30-min retention period with PSG monitoring, in which they either slept (n=24), quietly rested with their eyes closed (n=22), or completed a distractor task (n=28). Following the retention period, participants were tested on the same memory tasks they completed earlier. Results Percent improvement on the MST from the end of training to the end of the test session differed by condition, F(2, 73)=4.21, p=.019. Sleep and quiet rest led to nearly identical improvement (p=.95), with improvement in both of these conditions being significantly greater than in active wake (sleep vs. active wake: p=.01; quiet rest vs. active wake: p=.02). Similarly, retention of the Icelandic-English word pairs differed by condition (F(2, 73)=5.68, p=.005), with sleep and quiet rest demonstrating nearly identical memory change over time (p=.81), and retention in both of these conditions being significantly higher than in active wake (sleep vs. active wake: p=.007; quiet rest vs. active wake: p=.004). Conclusion These data suggest that sleep and quiet rest can exert an equivalent effect on memory consolidation for both declarative and procedural memory, at least across very brief retention durations. Therefore, neurobiology specific to sleep might not be necessary to induce offline improvement in memory across short intervals. Support This research was supported by National Institutes of Health Award R15MH107891.