0093 Superior Sleep in Highly Superior Autobiographical Memory

Abstract Introduction Individuals with highly superior autobiographical memory (HSAM) have the rare ability to instantly recall nearly every day of their adult lives. Previous research indicates that the extraordinary abilities of HSAM individuals are not a result of better memory encoding. Rather, HSAM individuals appear to not forget as easily as other individuals. One possibility is that enhanced memory consolidation during sleep may allow for stronger autobiographical memories that are more resistant to forgetting in HSAM individuals. Thus, aspects of sleep previously implicated in memory consolidation, including slow-oscillatory activity, sleep spindles, and synchrony between slow-oscillations and sleep spindles during non-REM sleep, may be enhanced in HSAM. Methods Overnight polysomnography was measured for two nights in HSAM individuals (n = 9) and in controls (n = 13) matched in age, sex, race, and education level to the HSAM individuals. The first night served as an adaptation night. All participants also completed brief neuropsychological assessments of episodic memory and intelligence and subjective measures of sleep and daytime sleepiness. Results No group differences were observed in the neuropsychological assessments or in the subjective measures of sleep and daytime sleepiness. Likewise, there were no group differences in total sleep time, time spent in each sleep stage, or in frontal non-REM slow-oscillatory power (.5 – 1.5 Hz). However, HSAM individuals showed higher non-REM sleep spindle density than controls at frontal, central, and parietal sites, with the largest increase at parietal sites. Furthermore, during non-REM sleep, spindles were more precisely coupled to the peaks of the slow oscillations in HSAM individuals than in controls at parietal sites. Conclusion These results are the first to demonstrate that aspects of sleep physiology previously implicated in memory consolidation, including sleep spindles and coupling between sleep spindles and slow oscillations, are enhanced in individuals with HSAM. This suggests that superior memory consolidation contributes to superior autobiographical memory in HSAM and increases our understanding of this fascinating condition, laying the groundwork for future studies aimed at leveraging sleep/memory connections for improving memory. Support (if any) McKnight Endowment Fund for Neuroscience