A18 SLEEP, Volume 44, Abstract Supplement, 2021 A. Basic and Translational Sleep and Circadian Science VI. Learning, Memory and Cognition even if the items were themselves correctly recognized, and regardless of their afective valence. These results indicate that TSD may disrupt binding of information to its context, which could explain TSD defcits in decision-making tasks that require novel associative linking. Furthermore, our fndings are important in real-world situations such as eyewitness accounts and perseveration of the infuence of misinformation. Support (if any): NIH grant R21 CA167691 and CDMRP award W81XWH-20-1-0442 041 ALTERATION OF THREAT-RELATED INFORMATION PROCESSING DURING EXTENDED SLEEP DEPRIVATION Sara Alger, 1 John Hughes, 1 Thomas Balkin, 1 Tracy Jill Doty 1 1 Walter Reed Army Institute of Research Introduction: Threat-related information is preferentially processed, facilitating quick and efcient responses. However, the impact of ex- tended sleep deprivation on perception of and response to threatening information is not well known. Sleep loss may increase amygdalar activity and negative mood, potentially facilitating threat processing. However, it also reduces cognitive function, possibly impairing ability to respond. The present study assessed the extent to which extended sleep deprivation modulates threat processing using a threat expect- ation paradigm. Methods: Twenty-one participants underwent one baseline night of sleep followed by 62hrs total sleep deprivation (TSD) and one re- covery night of sleep (12hrs). Threat expectation task performance was assessed at baseline, at multiple time points during TSD, and fol- lowing recovery sleep. To control for circadian infuence, performance at three 1100 sessions (baseline, 52hrs into TSD, and recovery) were compared. The threat expectation task involved determining whether a presented face was fearful (i.e., signaled threat) or neutral. Faces were presented at three expectation levels: 80%, 50%, and 20% chance of viewing a fearful face. Results: Overall, responses were faster (F=9.77, p=0.001) and more accurate (F=11.48, p=0.001) when the type of face (fearful or neu- tral) was expected. Accuracy signifcantly decreased over TSD (t=7.71, p<0.001) and recovered following subsequent sleep. Fear bias was cal- culated for accuracy (accuracy for fearful face minus neutral face). Under conditions of high expectation (80%) of viewing a fearful face, fear bias increased across TSD (t=-1.95, p=0.07). Although accuracy to both fearful and neutral faces signifcantly declined across TSD (both p<0.001), decline for neutral faces was greater, thus increasing fear bias. Importantly, the increased bias toward fear was still evident compared to baseline following a 12-hour recovery sleep opportunity, (t=-1.93, p=0.07). Conclusion: Extended sleep deprivation, common in operational en- vironments where there is also high expectation of encountering threat, impairs cognitive control and is thought to enhance amygdala activity. These data show that, consequently, cognitive resources become biased toward biologically adaptive behaviors (i.e., threat processing) at the expense of attending and responding more broadly to all stimuli. This behavior is not reversed with a single extended sleep opportunity. Support (if any): Department of Defense Military Operational Medicine Research Program (MOMRP) 042 A LOOK AT SEX DIFFERENCES ON SLEEP’S IMPACT ON WORKING MEMORY IMPROVEMENT Jing Zhang, 1 Lauren Whitehurst, 2 Sara Mednick 3 1 University of California, Irvine, 2 University of Kentucky, 3 University of California Irvine Introduction: Studies have shown that sleep afects working memory (WM) improvement, but specifc electrophysiological fea- tures are unclear (Sattari et al., 2019; MacDonald et al., 2018). In addition, sex diferences have been found in both sleep and working memory (Mong, 2016; Harness, 2008). The goal of this study is to identify sex diferences in EEG correlates of working memory over a night of sleep. Methods: Sixty-three healthy (33 females), college-aged adults without sleep disorder were enrolled. A 32-channel electroenceph- alogram (EEG) cap was used to record brain activity during sleep. Operation span (OS) task was used to evaluate WM performance. Participants reported to the laboratory in the evening, performed OS before sleep (test1) and after sleep (test2). Trials were divided into easy and hard trials based on the number of letters subjects had to recall. A repeated-measure analysis of variance was conducted to examine the efects of time and trial difculty. Paired-sample t-tests between test 1 and test 2 were conducted for males and females. Pearson’s cor- relations were examined between WM performance at test 1 and the diference score between test 1 and test 2 and EEG frequency bands. The Benjamini–Hochberg method was used to control for multiple comparisons. Results: There was an increase in performance across the night in WM hard trials across all subjects (F(1,62)=4.86, p=0.03), no efect for easy trials (p>0.05). Females, but not males, showed a signifcant de- crease in easy trials (t62= 2.40, p=0.02), while both males and females showed improvement in hard trials across the night. Females showed a positive correlation between test 1 hard trials and slow sigma, delta, slow oscillation in stage 3, this correlation is not seen in males. No cor- relations between overnight improvement and EEG bands were found. Conclusion: Consistent with previous studies, participants showed better memory performance over a night of sleep, and the WM per- formance was associated with slow wave activity in females. Slow sigma also plays a role in the WM performance for females, indicating a possible role of sleep spindles. These associations were not shown in males, suggesting sex hormones mediate sleep’s impact on WM performance. Support (if any): 043 SLEEP RESTRICTION AFFECTS MEMORY IN HEALTHY ADULTS: PRELIMINARY FINDINGS Molly Zimmerman, 1 Christiane Hale, 2 Adam Brickman, 3 Lok- Kin Yeung, 2 Justin Cochran, 2 Marie-Pierre St-Onge 2 1 Fordham University, 2 Columbia University Irving Medical Center, 3 Columbia University Introduction: Sleep loss has a range of detrimental efects on cogni- tive ability. However, few studies have examined the impact of sleep restriction on neuropsychological function using an experimental de- sign. The goal of this study was to examine the extent to which main- tained insufcient sleep afects cognition in healthy adults compared to habitual adequate sleep. Methods: This study used a randomized, crossover, outpatient sleep restriction design. Adults who regularly slept at least 7 h/night, veri- fed by 2 weeks of screening with actigraphy, completed 2 phases of 6 weeks each: habitual sleep (>7 h of sleep/night) or sleep restriction (habitual sleep minus 1.5 h) separated by a 6-week washout period. During the sleep restriction phase, participants were asked to delay their bedtime by 1.5 hours/night while maintaining their habitual wake time. Neuropsychological function was evaluated with the NIH Toolbox Cognition Battery at baseline (week 0) and endpoint (week 6) of each intervention phase. The NIH Toolbox evaluates a range Downloaded from https://academic.oup.com/sleep/article/44/Supplement_2/A18/6260032 by guest on 23 October 2023