Project description:The emotional dysregulation and impaired working memory found after sleep loss can have severe implications for our daily functioning. Considering the intertwined relationship between emotion and cognition in stimuli processing, there could be further implications of sleep deprivation in high-complex emotional situations. Although studied separately, this interaction between emotion and cognitive processes has been neglected in sleep research. The aim of the present study was to investigate the effect of 1?night of sleep deprivation on emotional working memory. Sixty-one healthy participants (mean age: 23.4?years) were either sleep deprived for 1?night (n?=?30) or had a normal night's sleep (n?=?31). They performed an N-back task with two levels of working memory load (1-back and 3-back) using positive, neutral and negative picture scenes. Sleep deprivation, compared with full night sleep, impaired emotional working memory accuracy, but not reaction times. The sleep-deprived participants, but not the controls, responded faster to positive than to negative and neutral pictures. The effect of sleep deprivation was similar for both high and low working memory loads. The results showed that although detrimental in terms of accuracy, sleep deprivation did not impair working memory speed. In fact, our findings indicate that positive stimuli may facilitate working memory processing speed after sleep deprivation.
Project description:Sleep restriction and circadian clock disruption are associated with metabolic disorders such as obesity, insulin resistance, and diabetes. The metabolic pathways involved in human sleep, however, have yet to be investigated with the use of a metabolomics approach. Here we have used untargeted and targeted liquid chromatography (LC)/MS metabolomics to examine the effect of acute sleep deprivation on plasma metabolite rhythms. Twelve healthy young male subjects remained in controlled laboratory conditions with respect to environmental light, sleep, meals, and posture during a 24-h wake/sleep cycle, followed by 24 h of wakefulness. Two-hourly plasma samples collected over the 48 h period were analyzed by LC/MS. Principal component analysis revealed a clear time of day variation with a significant cosine fit during the wake/sleep cycle and during 24 h of wakefulness in untargeted and targeted analysis. Of 171 metabolites quantified, daily rhythms were observed in the majority (n = 109), with 78 of these maintaining their rhythmicity during 24 h of wakefulness, most with reduced amplitude (n = 66). During sleep deprivation, 27 metabolites (tryptophan, serotonin, taurine, 8 acylcarnitines, 13 glycerophospholipids, and 3 sphingolipids) exhibited significantly increased levels compared with during sleep. The increased levels of serotonin, tryptophan, and taurine may explain the antidepressive effect of acute sleep deprivation and deserve further study. This report, to our knowledge the first of metabolic profiling during sleep and sleep deprivation and characterization of 24 h rhythms under these conditions, offers a novel view of human sleep/wake regulation.
Project description:To gain insight into the dynamic molecular processes that are altered during prolonged wakefulness and during sleep. We performed an RNA expression profiling study examining temporal changes in the brain of Drosophila in relationship to the duration of prior sleep or wakefulness. Our experimental design allowed us to determine whether genes identified as differentially regulated between sleep and wakefulness were up- or down-regulated in these states. Because stimulation of the experimental animal during the normal sleep period is used to prolong wakefulness in most experimental paradigms, the interpretation of the effects of prolonged wakefulness is confounded by the effect of the perturbation stimulus itself on the animal’s biology. We controlled for this effect in our experimental paradigm by examining gene expression changes in response to identical stimulation but during the animal’s normal wakefulness. The design of our study also allowed us to control for circadian variation in gene expression, since we compared sleeping and sleep deprived flies at the same diurnal time. Keywords: sleep deprivation, time course, stress response
Project description:Sleep has been proposed to be a physiological adaptation to conserve energy, but little research has examined this proposed function of sleep in humans. We quantified effects of sleep, sleep deprivation and recovery sleep on whole-body total daily energy expenditure (EE) and on EE during the habitual day and nighttime. We also determined effects of sleep stage during baseline and recovery sleep on EE. Seven healthy participants aged 22 ± 5 years (mean ± s.d.) maintained ?8 h per night sleep schedules for 1 week before the study and consumed a weight-maintenance diet for 3 days prior to and during the laboratory protocol. Following a habituation night, subjects lived in a whole-room indirect calorimeter for 3 days. The first 24 h served as baseline – 16 h wakefulness, 8 h scheduled sleep – and this was followed by 40 h sleep deprivation and 8 h scheduled recovery sleep. Findings show that, compared to baseline, 24 h EE was significantly increased by ?7% during the first 24 h of sleep deprivation and was significantly decreased by ?5% during recovery, which included hours awake 25-40 and 8 h recovery sleep. During the night time, EE was significantly increased by ?32% on the sleep deprivation night and significantly decreased by ?4% during recovery sleep compared to baseline. Small differences in EE were observed among sleep stages, but wakefulness during the sleep episode was associated with increased energy expenditure. These findings provide support for the hypothesis that sleep conserves energy and that sleep deprivation increases total daily EE in humans.
Project description:Study objectiveSleep deprivation significantly reduces the ability to maintain a consistent alertness level and impairs vigilant attention. Previous studies have shown that longer inter-stimulus interval (ISI) are associated with faster reaction times (RTs) on the Psychomotor Vigilance Test (PVT). However, whether and how sleep deprivation interacts with this ISI effect remains unclear.MethodsN = 70 healthy adults (age range 20-50 years, 41 males) participated in a 5-day and 4-night in-laboratory controlled sleep deprivation study, including N = 54 in the experimental group with one night of total sleep deprivation and N = 16 in the control group without sleep loss. All participants completed a neurobehavioral test battery every 2 hours while awake, including a 10-minute standard PVT (PVT-S, N = 1626) and a 3-minute brief PVT (PVT-B, N = 1622). The linear approach to threshold with ergodic rate (LATER) model was used to fit the RT data.ResultsRT decreased significantly with longer ISI on the PVT-S and PVT-B. Increased ISI effect was found for both PVT-S and PVT-B during sleep deprivation compared to baseline or recovery sleep in the experimental group, whereas no differences in the ISI effect were found in the control group. The LATER model fitting indicated that changes in perceptual sensitivity rather than threshold adjustment may underlie the ISI effect.ConclusionsBoth standard and brief PVT showed a similar ISI effect on vigilant attention performance. Sleep deprivation increased the ISI effect on both PVT-S and PVT-B, which may be due to impaired temporal resolution and time estimation after sleep loss.
Project description:In the context of high-stakes tests, test takers who do not have enough time to complete a test rush toward the end and may engage in speeded behavior when tests do not penalize guessing. Using mathematical derivations and simulations, previous research showed that random guessing responses should attenuate interitem correlations, and therefore, decrease estimates of reliability. Meanwhile, other researchers showed that random guessing could in fact inflate reliability estimates using real data. We provide analytical derivations on how speededness could affect correlations between two dichotomous items in multiple ways, depending on the manifestation and prevalence of test speededness. Furthermore, we provide two simulation studies that evaluate the magnitude of impact of test speededness on interitem correlations and Cronbach's alpha. We found that the impact of test speededness can vary between item pairs and that it depends on the manifestation of test speededness and item level characteristics. Furthermore, speeded responses will, in general, attenuate or not affect reliability estimates, depending on the prevalence of such responses and conceptual interpretation of speeded responses. Implications of the findings are discussed.
Project description:The present study aimed to investigate the effects of intensive effort on egocentric distance perception according to different angles of view after sleep deprivation at the beginning (SDB) or at the end (SDE) of the night and after a normal sleep night (NNS). Ten male students soccer players (age 22.8 ± 1.3 years; body mass 72.0 ± 10.4 kg; body height 180.0 ± 3.0 cm) performed a repeated cycling (RS) exercise (10 × 6 s maximal cycling with 24 s in between) after SDB, SDE, and NNS. They were asked to estimate three distances (i.e. 15, 25, and 35 m) before and after RS from different angles of view [i.e. in front (0°) and in side (45° left and 45° right)]. For 35 m, distance estimation was better during NNS compared to SDB and SDE for the front and the two side angles either before or after RS (p < 0.05). Concerning 25 m, distance estimation was better after compared to before RS for the front angle during the NNS session (p < 0.05). For 15 m, distance estimation was better during NNS than SDB and SDE for the front and both side angles after RS (p < 0.05). We concluded that partial sleep deprivation negatively affected the estimation of the egocentric distance for the three angles of view either at rest or after RS exercise.
Project description:Analysis of the effects of sleep deprivation, recovery sleep, and three time-of-day controls on seven brain regions laser microdissected from mouse brain. The regions include the locus coeruleus, suprachiasmatic nucleus, hypocretin area, tuberomammillary nucleus, orbital cortex, posteromedial cortical amygdala, and entorhinal cortex. In this study, 7 brain regions were collected by laser microdissection from brain tissue of mice from 5 different treatment groups and used for microarray experiments. Four biological replicates were generated for each regionxcondition. Conditions are: SD, sleep deprivation for 6 hours from ZT0 - 6; SDC, time-of-day control for SD at ZT6; RS, recovery sleep for 4 hours following SD; RSC, time-of-day control for RS at ZT10; W, spontaneous waking at ZT18.
Project description:Analysis of the effects of sleep deprivation, recovery sleep, and three time-of-day controls on seven brain regions laser microdissected from mouse brain. The regions include the locus coeruleus, suprachiasmatic nucleus, hypocretin area, tuberomammillary nucleus, orbital cortex, posteromedial cortical amygdala, and entorhinal cortex.