1.
Sleep loss disrupts the neural signature of successful learning.
Guttesen, AÁV, Gaskell, MG, Madden, EV, Appleby, G, Cross, ZR, Cairney, SA
Cerebral cortex (New York, N.Y. : 1991). 2023;33(5):1610-1625
-
-
-
Free full text
-
Plain language summary
Understanding how sleep disturbances impair learning and memory is increasingly important in modern society, where many people fail to regularly obtain an adequate amount of sleep. The aim of this study was to investigate the relationship between sleep-associated consolidation and next-day learning and how suppressing slow-wave activity (SWA) [during slow-wave sleep, electrical activity in the brain changes while the body relaxes into deep and restorative rest] contributes to this relationship. This study was a within-subjects (n = 30), crossover design which showed that sleep improved both memory retention and next-day learning however, there was no evidence of a relationship between these measures or with SWA. Furthermore, an absence of sleep disrupts the neural operations underpinning memory encoding, leading to suboptimal performance. Authors conclude that an extended lack of sleep might disrupt the ability to draw upon semantic knowledge when encoding novel associations, necessitating the use of more surface-based and ultimately suboptimal routes to learning.
Abstract
Sleep supports memory consolidation as well as next-day learning. The influential "Active Systems" account of offline consolidation suggests that sleep-associated memory processing paves the way for new learning, but empirical evidence in support of this idea is scarce. Using a within-subjects (n = 30), crossover design, we assessed behavioral and electrophysiological indices of episodic encoding after a night of sleep or total sleep deprivation in healthy adults (aged 18-25 years) and investigated whether behavioral performance was predicted by the overnight consolidation of episodic associations from the previous day. Sleep supported memory consolidation and next-day learning as compared to sleep deprivation. However, the magnitude of this sleep-associated consolidation benefit did not significantly predict the ability to form novel memories after sleep. Interestingly, sleep deprivation prompted a qualitative change in the neural signature of encoding: Whereas 12-20 Hz beta desynchronization-an established marker of successful encoding-was observed after sleep, sleep deprivation disrupted beta desynchrony during successful learning. Taken together, these findings suggest that effective learning depends on sleep but not necessarily on sleep-associated consolidation.
2.
Effects of Two Physical Activity Interventions on Sleep and Sedentary Time in Pregnant Women.
Alomairah, SA, Knudsen, SP, Roland, CB, Molsted, S, Clausen, TD, Bendix, JM, Løkkegaard, E, Jensen, AK, Larsen, JE, Jennum, P, et al
International journal of environmental research and public health. 2023;20(7)
-
-
-
Free full text
Plain language summary
Pregnant women benefit from physical activity (PA) during pregnancy. The aim of this study was to assess the effect of the FitMum PA interventions on sleep quantity and quality and sedentary time (SED). This study was a secondary analysis of the FitMum study which included 220 healthy pregnant women. Participants were randomised to one of three groups. Results showed that pregnant women are prone to low sleep quality and high SED, which worsens as pregnancy progresses. Pregnant women who received structured supervised exercise training had better sleep quality and less SED than pregnant women receiving standard prenatal care when self-reported. Furthermore, when measured by a consumer activity tracker, no differences were observed between groups. Authors conclude that interventions that increase PA levels might improve sleep quality and decrease SED in pregnant women. Future behavioural interventions targeting pregnant women should include evidence-based content to improve sleep quality and reduce SED.
Abstract
Pregnancy is often associated with poor sleep and high sedentary time (SED). We investigated the effect of physical activity (PA) interventions on sleep and SED in pregnant women. A secondary analysis of a randomized controlled trial (n = 219) explored the effect of structured supervised exercise training (EXE) or motivational counseling on PA (MOT) compared to standard prenatal care (CON) on sleep and SED during pregnancy. Three times during pregnancy, sleep was determined by the Pittsburgh Sleep Quality Index (PSQI) and SED by the Pregnancy Physical Activity Questionnaire (PPAQ). Also, a wrist-worn consumer activity tracker measured sleep and SED continuously. Data from the activity tracker confirmed that sleep time decreases, and SED increases by approx. 30 and 24 min/day, respectively, from baseline (maximum gestational age (GA) week 15) to delivery. Compared to CON, the global PSQI score was better for EXE in GA week 28 (-0.8 [-1.5; -0.1], p = 0.031) and for both EXE and MOT in GA week 34 (-1 [-2; -0.5], p = 0.002; -1 [-2; -0.1], p = 0.026). In GA week 28, SED (h/day) from PPAQ was lower in EXE compared to both CON and MOT (-0.69 [-1; -0.0], p = 0.049; -0.6 [-1.0; -0.02], p = 0.042). In conclusion, PA interventions during pregnancy improved sleep quality and reduced SED.