Sleep advances : a journal of the Sleep Research Society最新文献

Carefully timed light exposure is a promising countermeasure to overcome the negative sleep and circadian implications of shift work. However, many lighting interventions are static and applied at the group level (e.g. light banks, changes to ambient lighting), which is not appropriate for all populations or settings. This study investigates whether individualized lighting exposure, via personal light treatment devices (PLTDs), can improve sleep, sustain projected performance, and entrain circadian rhythms with the work schedules of US Navy submariners. Submarines are a unique testbed for PLTD intervention because they provide a self-contained environment with little influence from outside schedules or lighting. Forty-two submariners were pseudo-randomly assigned to either the PLTD or Control group. PLTD group participants wore blue-light exposure glasses for ~40 minutes upon waking and blue-blocking glasses for ~2 hours before sleep; Control group participants did not use PLTDs. Both groups completed questionnaires assessing subjective sleep and mood before and after the 12-day intervention, and wore wrist actigraphy devices to objectively assess sleep, projected performance, and predicted circadian phase outcomes. Compared with the Control group, several objective and subjective sleep outcomes and projected performance scores were improved in the PLTD group. The PLTD group's predicted circadian phase (modeled from actigraphy-derived accelerometer data) more rapidly shifted to align with scheduled work periods. Compliance with PLTD use was high, with no major disruptions to operational duties reported. These data provide initial support for the use of PLTDs as a flexible and customizable countermeasure for fatigue, sleep loss, and circadian misalignment in an operational environment.

Robert Stickgold's research was among the earliest to rigorously quantify the effect of learning on dream content. As a result, we learned that dreaming is influenced by the activation of newly formed memory traces in the sleeping brain. Exactly how this happens is an ongoing area of investigation. Here, we test the hypothesis that participants are especially likely to dream of recent experiences, which overlap with well-established semantic networks. We created an artificial situation in which participants encountered new information about a person with which they have extensive past experience-a favorite celebrity. We tracked the effect of novel information about a favorite celebrity on participants' dream content across 3 consecutive nights and queried participants about other recent and remote memory sources of their dreams. While the celebrity manipulation failed to affect dream content, this dataset provides rich descriptive information about how recent and remote memory fragments are incorporated into dreams, and how multiple memory sources combine to create bizarre, imaginative scenarios. We discuss these observations in light of the proposed "memory updating" function of sleep-dependent memory consolidation, as well as Stickgold and Zadra's NEXTUP (Network Exploration to Understand Possibilities) model of dreaming. This paper is part of the Festschrift in honor of Dr Robert Stickgold.

An accumulating body of evidence suggests a bidirectional relationship between sleep and cardiovascular (CV) health. A high level of evidence has linked obstructive sleep apnea (OSA) with cardiovascular disease (CVD). Accordingly, clinical sleep medicine emphasizes the diagnosis and treatment of OSA in the context of promoting CV health. While continuous positive airway pressure (CPAP), the mainstay treatment for OSA, is effective in improving several sleep-related quality-of-life outcomes and leads to modest reductions in blood pressure, there is currently insufficient evidence to justify using CPAP alone for improving CVD outcomes in OSA. Sleep physicians are uniquely positioned to expand their focus beyond the evaluation of OSA and administering CPAP, in efforts to enhance the CV health of sleep patients. Herein, we suggest the role of sleep physicians as CV preventionists. Key focus areas for managing CV risk beyond CPAP therapy in OSA include identifying comorbid disorders that are vital for optimizing CV health. This involves risk-stratifying patients and providing appropriate counseling, referrals, and treatment as appropriate for comorbid sleep conditions such as insomnia and insufficient sleep, comorbid CV risk factors including hypertension, dyslipidemia, metabolic dysfunction-associated steatohepatitis, as well as counseling for weight management programs, smoking, and alcohol cessation. We urge sleep clinicians to play an active and integral role in optimizing the CV health of patients with sleep disorders.

Study objectives: Military veterans often suffer from chronic pain and sleep issues at a greater frequency than the general population, leading some to self-medicate with alcohol. While research shows a connection between sleep and pain, few studies have examined bidirectional links between sleep and pain at the daily level-or the extent to which alcohol use may moderate these associations.

Methods: Heavy-drinking veterans seeking treatment for insomnia (N = 109, 82.5% male, mean age 38.9 years) completed 14 days of morning diaries documenting sleep patterns, pain intensity, and alcohol consumption. Multilevel modeling examined within- and between-person associations between sleep (quality, duration, and efficiency) and next-day pain as well as pain and same-night sleep.

Results: Individuals with longer sleep duration, better sleep quality, and higher sleep efficiency (SE) reported lower pain levels compared to those with shorter sleep, poorer sleep quality, and lower SE (p values <.001 to .01). In addition, on days when individuals experienced better sleep quality compared to their own average, they reported lower pain levels the following day (p = .01). In contrast to hypotheses, daily pain levels did not predict sleep outcomes at the daily within-person level, although significant between-person correlations were noted. Daily alcohol intake did not affect these relationships.

Conclusions: Sleep quality is associated with the daily experience of pain among heavy-drinking veterans with insomnia. Daily variations in sleep quality significantly impact pain, irrespective of alcohol consumption, highlighting a predominantly unidirectional influence from sleep to pain. These findings underscore the importance of optimizing sleep to mitigate pain in this population.

Sleep is essential for maintaining optimal health. Both sleep duration and quality have been linked to various physiological functions and physical and mental health outcomes. Nutrition has been shown to impact sleep parameters, from the nutrient composition of foods, such as tryptophan levels, to the physiological response to foods, such as the glucose response. However, the relationship between glycemic control and sleep, and its impact on next-day benefits, particularly on cognitive performance, remains complex and is not fully understood. This narrative review aims to explore the relationship between glycemia and sleep, and how it may affect cognitive performance the following day. The review includes data from observational and interventional studies, discussing mechanisms of action that may explain the modulating effect of glycemia on sleep and cognition. The evidence suggests that lower postprandial glucose and low variation of nocturnal glucose are associated with better sleep quality and shorter sleep onset latency. Good sleep quality, in turn, is positively associated with cognitive processes such as sustained attention and memory consolidation measured the next day after sleep. Future research opportunities lie in investigating the effects of modulating the glycemic and insulinemic responses through evening meals on sleep quality and next-day cognitive performance. Well-designed clinical trials involving healthy individuals are necessary to establish the effects of these interventions. Controlling glycemic and insulinemic profiles through the evening meal may have significant implications for improving sleep quality and cognitive performance, with potential impact on individual mental health, productivity, and overall well-being.

Study objectives: Astrocytes change their intracellular calcium (Ca²⁺) concentration during sleep/wakefulness states in mice. Furthermore, the Ca²⁺ dynamics in astrocytes vary depending on the brain region. However, it remains unclear whether alterations in astrocyte activity can affect sleep-wake states and cortical oscillations in a brain region-dependent manner.

Methods: Astrocyte activity was artificially manipulated in mice using chemogenetics. Astrocytes in the hippocampus and pons, which are 2 brain regions previously classified into different clusters based on their Ca²⁺ dynamics during sleep-wakefulness, were focused on to compare whether there are differences in the effects of astrocytes from different brain regions.

Results: The chemogenetic activation of astrocytes in the hippocampus significantly decreased the total time of wakefulness and increased the total time of sleep. This had little effect on cortical oscillations in all sleep-wakefulness states. On the other hand, the activation of astrocytes in the pons substantially suppressed rapid eye movement (REM) sleep in association with a decreased number of REM episodes, indicating strong inhibition of REM onset. Regarding cortical oscillations, the delta wave component during non-REM sleep was significantly enhanced.

Conclusions: These results suggest that astrocytes modulate sleep-wakefulness states and cortical oscillations. Furthermore, the role of astrocytes in sleep-wakefulness states appears to vary among brain regions.

A central tenet of Freudian dream theory holds that there is thematic coherence within all dreams, even those containing scene and plot discontinuities. While other models support varying degrees of dream coherence, none address the question of how, or even whether, coherence can be identified in dreams with such discontinuities. Here, we objectively test the ability of judges to evaluate the coherence of individual dream narratives. Twenty reports with complete scene and plot discontinuities were collected, and half were cut apart at their discontinuities and their two halves spliced together with segments from dreams of other subjects. The remaining 10 reports were left intact. Judges correctly identified reports as intact or spliced only 57% of the time, a rate only slightly better than chance. Only 3 of the 20 reports, one intact and two spliced, were reliably scored correctly, while one intact report was mis-scored by 80% of the judges. Judges had no greater confidence in correct decisions than incorrect ones. Dream report features identified by the judges that were effectively used in scoring dreams included characters, locations and objects, while psychoanalytic content and writing style were least effectively used. In sum, we find no evidence that dream construction consistently results in identifiable thematic coherence. Rather, scene and plot discontinuities in many cases represent such complete breaks as to be unrecognizable. We conclude that the finding of continuity by those reading these reports reflects ineluctable synthetic activity in the mind of the dream researcher or analyst rather than in the mind of the dreamer. This paper is part of the Festschrift in honor of Dr. Robert Stickgold.

Model organisms such as Drosophila are powerful tools to study the genetic basis of sleep. Previously, we identified the genes pointed and Arginine kinase 1 using selective breeding for long and short sleep duration in an outbred population of Drosophila. pointed is a transcription factor that is part of the epidermal growth factor receptor signaling pathway, while Arginine kinase 1 is involved in proline and arginine metabolism. Conserved orthologs of these genes exist in mice, leading us to hypothesize that they would also impact sleep in a murine model. We generated mutations in the murine orthologs Ets1 and Ckm using CRISPR in a C57BL/6N background and used video analysis to measure sleep in the mice. Both mutations affected sleep parameters, and the effects were observed predominantly in female mice, with males showing fewer differences from littermate controls. The study of natural populations in flies therefore leads to candidate genes with functional conservation on sleep in mammals.

Study objectives: Sleep spindles, defining electroencephalographic oscillations of nonrapid eye movement (NREM) stage 2 sleep (N2), mediate sleep-dependent memory consolidation (SDMC). Spindles are also thought to protect sleep continuity by suppressing thalamocortical sensory relay. Schizophrenia is characterized by spindle deficits and a correlated reduction of SDMC. We investigated whether this relationship is mediated by sleep fragmentation.

Methods: We detected spindles (12-15 Hz) during N2 at central electrodes in overnight polysomnography records from 56 participants with chronic schizophrenia and 59 healthy controls. Our primary measures of sleep continuity were the sleep fragmentation index and, in a subset of the data, visually scored arousals. SDMC was measured as overnight improvement on the finger-tapping motor sequence task.

Results: Participants with schizophrenia showed reductions of both spindle density (#/min) and SDMC in the context of normal sleep continuity and architecture. Spindle density predicted SDMC in both groups. In contrast, neither increased sleep fragmentation nor arousals predicted lower spindle density or worse SDMC in either group.

Conclusions: Our findings fail to support the hypothesis that sleep fragmentation accounts for spindle deficits, impaired SDMC, or their relationship in individuals with chronic schizophrenia. Instead, our findings are consistent with the hypothesis that spindle deficits directly impair memory consolidation in schizophrenia. Since sleep continuity and architecture are intact in this population, research aimed at developing interventions should instead focus on understanding dysfunction within the thalamocortical-hippocampal circuitry that both generates spindles and synchronizes them with other NREM oscillations to mediate SDMC.

Study objectives: The complete blood count (CBC) is one of the most commonly ordered blood tests with a large range of reference values that does not consider time of day for interpretation. Our objective was to systematically review this topic to report on peak and trough timing of CBC values.

Methods: A systematic search was performed for studies evaluating any component of the CBC with at least three collections over 24 hours. The studies were screened based on the predetermined eligibility criteria. Meta-analysis of aggregated data was analyzed with polynomial functions and forest plots.

Results: In total, 164 full-text articles were screened and 32 included in the final analysis with 548 total patients considering either leukocytes (n = 13), erythrocytes (n = 7), hemoglobin (n = 5), hematocrit (n = 5), platelets (n = 12), neutrophils (n = 11), lymphocytes (n = 13), monocytes (n = 8), eosinophils (n = 15), or basophils (n = 9). CBC components were analyzed by polynomial and forest plot analysis. Lymphocytes fitted best to a third-degree polynomial function (p = .010) with peak at 2264.87 cells/µL at 23:54 (CI: 1783.44 to 2746.31) with a trough of 1598.91 cells/µL at 10:47 (CI: 1230.12 to 1967.71). Lymphocytes and eosinophils peaked overnight, while erythrocytes, hemoglobin, and hematocrit peaked in the morning, and platelets, neutrophils, monocytes, and basophils peaked in late afternoon. Limitations include small sample size and significant study heterogeneity.

Conclusion: We identified a limited scope of studies characterizing CBC component rhythms. However, we still noted significant differences, particularly with lymphocytes. Future work should evaluate larger datasets to inform time-dependent interpretation of the CBC as we move toward precision medicine.