Targeted memory reactivation of face-name learning depends on ample and undisturbed slow-wave sleep

Face memory, including the ability to recall a person’s name, is of major importance in social contexts. Like many other memory functions, it may rely on sleep. We investigated whether targeted memory reactivation during sleep could improve associative and perceptual aspects of face memory. Participants studied 80 face-name pairs, and then a subset of spoken names with associated background music was presented unobtrusively during a daytime nap. This manipulation preferentially improved name recall and face recognition for those reactivated face-name pairs, as modulated by two factors related to sleep quality; memory benefits were positively correlated with the duration of stage N3 sleep (slow-wave sleep) and negatively correlated with measures of sleep disruption. We conclude that (a) reactivation of specific face-name memories during sleep can strengthen these associations and the constituent memories, and that (b) the effectiveness of this reactivation depends on uninterrupted N3 sleep.

Effect of sleep and mood on academic performance—at interface of physiology, psychology, and education

Academic achievement and cognitive functions are influenced by sleep and mood/emotion. In addition, several other factors affect learning. A coherent overview of the resultant interrelationships is essential but has not been presented till date. This unique and interdisciplinary review sits at the interface of physiology, psychology, and education. It compiles and critically examines the effects of sleep and mood on cognition and academic performance while including relevant conflicting observations. Moreover, it discusses the impact of several regulatory factors on learning, namely, age, gender, diet, hydration level, obesity, sex hormones, daytime nap, circadian rhythm, and genetics. Core physiological mechanisms that mediate the effects of these factors are described briefly and simplistically. The bidirectional relationship between sleep and mood is addressed. Contextual pictorial models that hypothesise learning on an emotion scale and emotion on a learning scale have been proposed. Essentially, convoluted associations between physiological and psychological factors, including sleep and mood that determine academic performance are recognised and affirmed. The emerged picture reveals far more complexity than perceived. It questions the currently adopted ‘one-size fits all’ approach in education and urges to envisage formulating bespoke strategies to optimise teaching-learning approaches while retaining uniformity in education. The information presented here can help improvise education strategies and provide better academic and pastoral support to students during their academic journey.

Effects of post short nap sleep inertia on cognitive and psychomotor task performance

Introduction: Sleep inertia, a detrimental effect of daytime nap, may affect cognitive functions following awakening. The present study aimed to assess the effects of sleep inertia on cognitive and psychomotor tasks following short nap of 30 min taken in the afternoon hours, a realistic probability in the aerospace operational environment. Material and Methods: In a repetitive measure design, 30 healthy male volunteers having adequate sleep the previous night, were tested for changes in cognitive and psychomotor performance following 30 min of nap after lunch at the Sleep-cum-Group confinement lab. Post nap longitudinal testing for dual task (DT) test and Stroop test was carried out in periodic intervals for 40 min. DT response time (DTRT), DT lag error (DTLE), DT correct clicks (DTCC) and response time difference (Stroop Effect [SE]) were analyzed as performance measures. Results: There was a significant increase in DTRT (χ2 =11.13, P = 0.011) in the post-nap period as compared to pre-nap baseline values. No significant changes were observed in other parameters vis DTLE, DTCC, and SE. Post-hoc analysis revealed that the increase of DTRT was significant at 6 min post-nap session; following which the changes were not statistically significant. Conclusion: Sleep inertia was found to affect speed component of the task rather than accuracy in a post-nap period of 30 min. The effect was significant at 6 min following awakening and after that, the effects got dissipated. Although nap can be an effective strategy for sleep-alertness management, the effects of sleep inertia have to be borne in mind, especially during sustained military operations.

The Prevalence of Use of Various Post-Exercise Recovery Methods after Training among Elite Endurance Athletes

There is now compelling evidence of the effectiveness of a range of post-exercise recovery techniques, including extended nights of sleep, cold water immersion, massage, and compression garments. Currently, limited information is available on post-exercise recovery methods used by elite endurance athletes. Therefore, this study investigated the actual methods of recovery used in this group of athletes. Google Forms were used to collect information on the recovery methods used by elite endurance track and field athletes (n = 153, 61.4% men, 38.6% women; average age: 22.7 ± 4.6 years). The most used methods of recovery were sauna bathing (96.7%), massage (86.9%), daytime nap (81.0%), and long night sleep (at least 9h) (61.4%). Recovery methods with proven effectiveness such as cold water immersion and compression garments were rarely used (15.0% and 7.8%, respectively). Overall, recovery methods were used more often when the tiers of the track and field athletes were higher. Massage and sauna bathing were the most used methods of post-exercise recovery among Russian endurance track and field athletes. In most cases, they were used in conjunction with short daytime nap and long night sleep. Higher tier athletes were more likely to use sauna bathing, massage, long night sleep, and daytime nap but not cold water immersion and compression garments as recovery methods; however, all these methods except for cold water immersion were widely used among elite-tier athletes.

P083 Age of Nap Cessation and Short-term Social-Emotional Functioning in Early Childhood

Background Daytime nap cessation, in which sleep transitions from biphasic to monophasic sleep, is a common feature of early childhood sleep patterns. Yet, to date, understanding of the meaning of this transition for children’s development is not well understood. The aim of this study is to investigate the relationship between the age of nap cessation and behavioral and social functioning in young children. Methods Parent report data from the Effective Early Educational Experiences (E4Kids) study of N=1700 children from across Queensland and Victoria is analysed. Data on age of nap cessation, Strengths and Difficulties Questionnaire (SDQ), and Social Skills Improvement Scale (SSIS) is examined to determine whether age of nap cessation is associated with internalizing and externalizing behaviour and social skills in early childhood. Progress to date Data collection and cleaning are complete. Initial descriptive analyses and identification of significant covariates are underway, and final regressions will be run shortly. Intended outcome/ Impact This study provides new evidence on the relationship between age of napping cessation and social-emotional outcomes in young children. Such evidence is important for building an understanding of the role of sleep cessation in children’s early development, and to inform practitioners and parents responsible for supporting children’s sleep.

Effects of a Short Daytime Nap on the Cognitive Performance: A Systematic Review and Meta-Analysis

Background: Napping in the workplace is under debate, with interesting results on work efficiency and well-being of workers. In this systematic review and meta-analysis, we aimed to assess the benefits of a short daytime nap on cognitive performance. Methods: PubMed, Cochrane Library, ScienceDirect and PsycInfo databases were searched until 19 August 2021. Cognitive performance in working-aged adults, both before and following a daytime nap or under control conditions (no nap), was analysed by time and by type of cognitive function (alertness, executive function and memory). Results: We included 11 studies (all in laboratory conditions including one with a subgroup in working conditions) for a total of 381 participants. Mean duration of nap was 55.4 ± 29.4 min. Overall cognitive performance did not differ at baseline (t0) between groups (effect size −0.03, 95% CI −0.14 to 0.07), and improved in the nap group following the nap (t1) (0.18, 0.09 to 0.27), especially for alertness (0.29, 0.10 to 0.48). Sensitivity analyses gave similar results comparing only randomized controlled trials, and after exclusion of outliers. Whatever the model used, performance mainly improved until 120 min after nap, with conflicting results during the sleep inertia period. Early naps in the afternoon (before 1.00 p.m.) gave better cognitive performance (0.24, −0.07 to 0.34). The benefits of napping were independent of sex and age. Duration of nap and time between nap and t1 did not influence cognitive performance. Conclusions: Despite the fact that our meta-analyses included almost exclusively laboratory studies, daytime napping in the afternoon improved cognitive performance with beneficial effects of early nap. More studies in real work condition are warranted before implementing daytime napping at work as a preventive measure to improve work efficiency.

Short daytime napping reduces the risk of cognitive decline in community-dwelling older adults: a 5-year longitudinal study

Background Beneficial effects of napping on cognition have been suggested in cross-sectional studies. This study aimed to clarify longitudinal associations between cognitive decline and sleep characteristics, particularly daytime napping, over a 5-year period in older adults. Methods Study participants were 389 community-dwelling individuals aged ≥65 years living in Ojiya City, Niigata, Japan. Baseline and follow-up examinations were conducted in 2011–2013 and 2016–2018, respectively. Trained nurses visited and interviewed participants to collect the following information at baseline and follow-up: demographic characteristics, disease history, lifestyle habits including bedtime, sleeping hours, and daytime nap duration, and cognitive function. The assessment of cognitive function was performed using the revised Hasegawa’s dementia scale (HDS-R), with cognitive decline defined as a change in the HDS-R of ≤ − 3 over 5 years. Odds ratios (ORs) for cognitive decline were calculated using multiple logistic regression analysis. Results Mean age of participants was 74.6 years (SD 6.4), and the cumulative incidence of cognitive decline was 106/389 (27.3%). The adjusted OR for 1–29 min daytime napping was significantly lower compared to that for no napping (OR = 0.47, 95%CI: 0.23–0.96). Earlier bedtime was associated with cognitive decline (adjusted P for trend = 0.0480). Conclusion Short daytime napping (< 30 min) reduces the risk of cognitive decline over 5 years for community-dwelling older people. A future study will be necessary to confirm the effect of short napping on the reduction of risk for clinically diagnosed dementia.

Sleep maturation influences cognitive development of preterm toddlers

Our recent study on full-term toddlers demonstrated that daytime nap properties affect the distribution ratio between nap and nighttime sleep duration in total sleep time but does not affect the overall total amount of daily sleep time. However, there is still no clear scientific consensus as to whether the ratio between naps and nighttime sleep or just daily total sleep duration itself is more important for healthy child development. In the current study, to gain an answer to this question, we examined the relationship between the sleep properties and the cognitive development of toddlers born prematurely using actigraphy and the Kyoto scale of psychological development (KSPD) test. 101 premature toddlers of approximately 1.5 years of age were recruited for the study. Actigraphy units were attached to their waist with an adjustable elastic belt for 7 consecutive days and a child sleep diary was completed by their parents. In the study, we found no significant correlation between either nap or nighttime sleep duration and cognitive development of the preterm toddlers. In contrast, we found that stable daily wake time was significantly associated with better cognitive development, suggesting that sleep regulation may contribute to the brain maturation of preterm toddlers.

A Daytime Nap Does Not Enhance the Retention of a First-Order or Second-Order Motor Sequence

This study examined the effects of a daytime nap on the retention of implicitly learnt “first-order conditional” (FOC) and “second-order conditional” (SOC) motor sequences. The implicit learning and retention of a motor sequence has been linked to the neural processes undertaken by the basal ganglia and primary motor cortex (i.e., procedural memory system). There is evidence, however, suggesting that SOC learning may further rely on the hippocampus-supported declarative memory system. Sleep appears to benefit the retention of information processed by the declarative memory system, but not the procedural memory system. Thus, it was hypothesized that sleep would benefit the retention of a SOC motor sequence but not a FOC sequence. The implicit learning and retention of these sequences was examined using the Serial Reaction Time Task. In this study, healthy adults implicitly learnt either a FOC (n = 20) or a SOC sequence (n = 20). Retention of both sequences was assessed following a daytime nap and period of wakefulness. Sleep was not found to improve the retention of the SOC sequence. There were no significant differences in the retention of a FOC or a SOC sequence following a nap or period of wakefulness. The study questions whether the declarative memory system is involved in the retention of implicitly learnt SOC sequences.

Early Impact of Lockdown on Daily Activity Behaviors and Sleep Pattern in Small Indian Population

Objectives: Lockdown has resulted in unprecedented changes in daily behaviors including depression. We hypothesized that the lockdown would impact our daily behavior such as sleep-wake cycle, eating time, physical activities, work hours, sleep quality, etc. We also observed the depression among the population during the lockdown. Methods: This is a cross-sectional study was conducted after one month of the imposition of the lockdown (between April 26 – May 05, 2020) by an online questionnaire designed using a google form filled by individuals from different professions (N=251). The analysis was performed using one-way RM ANOVA followed by Bonferroni’s multiple analysis post hoc test. Significance was taken at P< 0.0001. Results: The sleep-wake cycle, breakfast time was significantly delayed during the lockdown compared to weekdays before lockdown days. Total 60% of volunteers reported good sleep, 32% had increased daytime nap, maximum time spent in the usage of social media 29%, and 79% showed increased usage of electronic gadgets. The physical activity and work hours were reduced to 57% and 58% respectively. It seems that lockdown forced people to undergo depression as 54% were depressed. Conclusion: This is the first study to conclude the changes in daily behaviors including depression. Overall, delay in the sleep-wake cycle, breakfast timings, increased sedentary lifestyle, reduction in their work hours, addiction of electronic gadgets, spending maximum time on social media with increased depression. This study is helpful for the public health systems to create awareness regarding the sleep and health improvements during as well as after lockdown.