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Studying paradoxical sleep homeostasis requires the specific and efficient deprivation of paradoxical sleep and the evaluation of the subsequent recovery period. With this aim, the small-platforms-over-water technique has been used extensively in rats, but only rare studies were conducted in mice, with no sleep data reported during deprivation. Mice are used increasingly with the emergence of transgenic mice and technologies such as optogenetics, raising the need for a reliable method to manipulate paradoxical sleep. To fulfil this need, we refined this deprivation method and analysed vigilance states thoroughly during the entire protocol. We also studied activation of hypocretin/orexin and melanin-concentrating hormone neurones using Fos immunohistochemistry to verify whether mechanisms regulating paradoxical sleep in mice are similar to those in rats. We showed that 48 h of deprivation was highly efficient, with a residual amount of paradoxical sleep of only 2.2%. Slow wave sleep and wake quantities were similar to baseline, except during the first 4 h of deprivation, where slow wave sleep was strongly reduced. After deprivation, we observed a 124% increase in paradoxical sleep quantities during the first hour of rebound. In addition, 34% of hypocretin/orexin neurones were activated during deprivation, whereas melanin-concentrated hormone neurones were activated only during paradoxical sleep rebound. Corticosterone level showed a twofold increase after deprivation and returned to baseline level after 4 h of recovery. In summary, a fairly selective deprivation and a significant rebound of paradoxical sleep can be obtained in mice using the small-platforms-over-water method. As in rats, rebound is accompanied by a selective activation of melanin-concentrating hormone neurones. [ABSTRACT FROM AUTHOR]

This paper discusses the significance for the philosophy of perception and aesthetics of certain productions of the 'offline brain'. These are experienced in hypnagogic and other trance states, and in disease- or drug-induced hallucination. They bear a similarity to other visual patterns in nature, and reappear in human artistry, especially of the craft type. The reasons behind these resonances are explored, along with the question why we are disposed to find geometrical complexity and 'supercolouration' beautiful. The paper concludes with a plea on behalf of neuroaesthetics, but with a caution or two. [ABSTRACT FROM AUTHOR]

Significant inter-individual differences in vigilance decline following sleep deprivation exist. We characterized functional connectivity in 68 healthy young adult participants in rested wakefulness and following a night of total sleep deprivation. After whole brain signal regression, functionally connected cortical networks during the well-rested state exhibited reduced correlation following sleep deprivation, suggesting that highly integrated brain regions become less integrated during sleep deprivation. In contrast, anti-correlations in the well-rested state became less so following sleep deprivation, suggesting that highly segregated networks become less segregated during sleep deprivation. Subjects more resilient to vigilance decline following sleep deprivation showed stronger anti-correlations among several networks. The weaker anti-correlations overlapped with connectivity alterations following sleep deprivation. Resilient individuals thus evidence clearer separation of highly segregated cortical networks in the well-rested state. In contrast to corticocortical connectivity, subcortical–cortical connectivity was comparable across resilient and vulnerable groups despite prominent state-related changes in both groups. Because sleep deprivation results in a significant elevation of whole brain signal amplitude, the aforesaid signal changes and group contrasts may be masked in analyses omitting their regression, suggesting possible value in regressing whole brain signal in certain experimental contexts. [ABSTRACT FROM AUTHOR]

Introduction: Noradrenergic cells in LC participate in the process of cortical activation and behavioral arousal. The evidence suggests that locus ceoruleus (LC) plays an important role in the sleep-wake cycle. The aim of this study was stereological estimation of cavity caused by lesion and assessment of sleep stages after bilateral lesion of the LC. Materials and Methods: Male Wistar rats weighting 250-275 gr were divided into four groups (control: n=6, sham: n=6, lesion1: n=6 and lesion2: n=6). 6 hydroxydopamine (6 OHDA) (2µg/0.5µl and 4µg/1µl) was sterotaxically injected bilaterally into LC to produced lesion. For sleep recording 3 EEG and 2 EMG electrodes were implanted respectively in the skull and dorsal neck muscle. Recordings were taken before and 7, 21 and 42 days after lesion. After 7 weeks, Rats first were anesthetized and then their brains were removed and cut in 7 µm serial sections and stained with cresyl violet. The volume of LC and the lesion induced cavity were evaluated through the stereological technique. Results: Lesion - induced cavity volume (0.5 µl) was restricted to LC, whereas Another group (1 µl), total LC and structures adjacent to the LC were also damaged. A significant decrease was seen in non-rapid eye movement (NREM) and paradoxical sleep (PS) stages and a significant increase was seen in duration of wake and paradoxical sleep without atonia (PS-A) in lesion group in comparison with control and sham groups. Conclusion: The results of this study demonstrate 2µg/0.5µl 6-OHDA is suitable dose for LC lesion and bilateral lesion of LC causing disrupt wake, NREM, PS and also produce the PS-A. [ABSTRACT FROM AUTHOR]

The study aimed to test whether a shift in chronotype (determined by mid-sleep on free days) is associated with alterations in psychological well-being and sleep parameters. One hundred and seventeen undergraduates were tested in longitudinal study with four repeated measures. Measurements were taken during spring in three-week intervals and each measurement consisted of self-reported sleep parameters on work and free days (i.e. bedtime, sleep latency, wake time, sleep onset, mid-sleep time, social jetlag), satisfaction with life, and mood (energetic arousal, tense arousal, hedonic tone). Between-subjects analyses revealed earlier chronotypes, as compared to the later ones, showing lower tense arousal, higher energetic arousal and life satisfaction, earlier bedtime, sleep onset and offset on both work and free days, longer sleep duration and shorter sleep latency on workdays, and less social jetlag. Within-subjects analyses revealed increasing photoperiod associated with a shift toward earlier chronotype, decrease in social jetlag, and shortening sleep latency. The seasonal shift toward earlier chronotype was not associated with alterations in mood or life satisfaction, but it was associated with a shift toward earlier bedtimes and longer sleep duration on workdays, decrease in sleep latency, and social jetlag. Results from the within-subjects analyses were consistent with the results of between-subjects analyses regarding sleep–wake functioning, but inconsistent regarding psychological outcomes. [ABSTRACT FROM AUTHOR]

Two sources of information (parent-reported sleep diaries and actigraph records) were used to investigate how toddler sleep characteristics (bed time/sleep onset, wake time/sleep offset, total nighttime sleep, and total sleep time) are related to sleep problems and temperament. There were 64 toddler participants in the study. Consistent with studies of older children, parent reports differed from actigraph-based records. The findings that parent-reported and actigraph-recorded sleep characteristics varied as a function of parent report of toddler sleep problems and temperament add needed information on toddler sleep. Such information may contribute to improving parents’ awareness of their child’s sleep characteristics and correlates of problem sleep. [ABSTRACT FROM PUBLISHER]

The current study used event-related potentials to examine a candidate process through which sleep difficulties affect attentional processing in toddlers. Fifteen toddlers participated in an auditory Oddball task while neurophysiological data were collected. Sleep deficits were assessed using actigraphs, and attention was examined with a sustained attention task. A P3-like component was elicited from the toddlers, and longer target P3 latencies were associated with poorer sustained attention and irregular sleep. Findings suggest that irregular sleep is associated with less efficient attentional processing as reflected by the P3 component, and that longer target P3 latencies are associated with poorer sustained attention. [ABSTRACT FROM AUTHOR]

This longitudinal study assessed the role of early sleep patterns in predicting attention regulation and behavior problems. Sleep of 43 infants was assessed using actigraphy at 12 months of age and then reassessed when the children were 3–4 years old. During this follow-up, their attention regulation and behavior problems were also assessed using a computerized test and parental reports. Lower quality of sleep in infancy significantly predicted compromised attention regulation and behavior problems. These findings underscore the need to identify and treat early sleep problems. [ABSTRACT FROM PUBLISHER]

EEG, EMG, and EOG are very informative signals recorded in polysomnography (PSG) and used for sleep staging. Their reliable acquisition at home, however, is difficult. In comparison, ECG and thoracic respiratory (R) signals are easier to record and can be useful in home sleep monitoring systems. The simultaneous utilization of Heart Rate Variability (HRV) and respiratory (R) signals seems a plausible scenario as both heart rate (HR) and respiration rate (RR) vary during different sleep states. Therefore, we explored the combined discriminative capacity (accuracy, sensitivity, and specificity) of ECG/R signals in automatic sleep staging. As baseline, we classified the wakefulness, Stage 2, SWS (slow wave sleep) and REM sleep by using a Support Vector Machine (SVM) fed with a set of features extracted from: (a) HRV (34-features), (b) HRV/ECG-Derived Respiration (45-features), and (c) combined HRV/R (45-features) signals. Approach (a) produced reasonable discriminative capacity, while approach (b) significantly improved the classification; however, the best outcomes were achieved by using approach (c). Then, we enhanced the SVM classifier with the Recursive Feature Elimination (RFE) method. The classification results were improved with 35 out of the 45 HRV/RS-EDR features. In comparison, best results were obtained by combining 27 out of the 45 features derived from HRV/R signals, in which the optimal feature set selected by the SVM-RFE method, included a combination of time domain, time-frequency, and fractal features, as well as entropies. Overall, these improvements revealed that it is possible to simplify home monitoring of sleep disorders and achieve high discriminative capacity (accuracy = 89.32%, specificity = 92.88%, and sensitivity = 78.64%) in automatic sleep staging by the exclusive recording of cardiorespiratory signals. [ABSTRACT FROM AUTHOR]

Higher cognitive functions require the integration and coordination of large populations of neurons in cortical and subcortical regions. Oscillations in the high frequency band (30–100 Hz) of the electroencephalogram (EEG), that have been postulated to be a product of this interaction, are involved in the binding of spatially separated but temporally correlated neural events, which results in a unified perceptual experience. The extent of this functional connectivity can be examined by means of the mathematical algorithm called “coherence”, which is correlated with the “strength” of functional interactions between cortical areas. As a continuation of previous studies in the cat [6,7] , the present study was conducted to analyze EEG coherence in the gamma band of the rat during wakefulness (W), non-REM (NREM) sleep and REM sleep. Rats were implanted with electrodes in different cortical areas to record EEG activity, and the magnitude squared coherence values within the gamma frequency band of EEG (30–48 and 52–100 Hz) were determined. Coherence between all cortical regions in the low and high gamma frequency bands was greater during W compared with sleep. Remarkably, EEG coherence in the low and high gamma bands was smallest during REM sleep. We conclude that high frequency interactions between cortical areas are radically different during sleep and wakefulness in the rat. Since this feature is conserved in other mammals, including humans, we suggest that the uncoupling of gamma frequency activity during REM sleep is a defining trait of REM sleep in mammals. [ABSTRACT FROM AUTHOR]

Chronic sleep restriction (SR) has deleterious effects on cognitive performance that can be counteracted by light exposure. However, it is still unknown if naturalistic light settings (dawn simulating light) can enhance daytime cognitive performance in a sustainable matter. Seventeen participants were enrolled in a 24-h balanced cross-over study, subsequent to SR (6-h of sleep). Two different light settings were administered each morning: a) dawn simulating light (DsL; polychromatic light gradually increasing from 0 to 250 lx during 30 min before wake-up time, with light around 250 lx for 20 min after wake-up time) and b) control dim light (DL; <8 lx). Cognitive tests were performed every 2 h during scheduled wakefulness and questionnaires were completed hourly to assess subjective mood. The analyses yielded a main effect of “light condition” for the motor tracking task, sustained attention to response task and a working memory task (visual 1 and 3-back task), as well as for the Simple Reaction Time Task, such that participants showed better task performance throughout the day after morning DsL exposure compared to DL. Furthermore, low performers benefited more from the light effects compared to high performers. Conversely, no significant influences from the DsL were found for the Psychomotor Vigilance Task and a contrary effect was observed for the digit symbol substitution test. No light effects were observed for subjective perception of sleepiness, mental effort, concentration and motivation. Our data indicate that short exposure to artificial morning light may significantly enhance cognitive performance in a domain-specific manner under conditions of mild SR. [ABSTRACT FROM AUTHOR]

Cortical interneurons, immunoreactive for neuronal nitric oxide synthase (nNOS) and the receptor NK1, express the functional activity marker Fos selectively during sleep. NREM sleep 'pressure' is hypothesized to accumulate during waking and to dissipate during sleep. We reported previously that the proportion of Fos+ cortical nNOS/NK1 neurons is correlated with established electrophysiological markers of sleep pressure. As these markers covary with the amount of NREM sleep, it remained unclear whether cortical nNOS/NK1 neurons are activated to the same degree throughout NREM sleep or whether the extent of their activation is related to the sleep pressure that accrued during the prior waking period. To distinguish between these possibilities, we used hypnotic medications to control the amount of NREM sleep in rats while we varied prior wake duration and the resultant sleep pressure. Drug administration was preceded by 6 h of sleep deprivation (SD) ('high sleep pressure') or undisturbed conditions ('low sleep pressure'). We find that the proportion of Fos+ cortical nNOS/NK1 neurons was minimal when sleep pressure was low, irrespective of the amount of time spent in NREM sleep. In contrast, a large proportion of cortical nNOS/NK1 neurons was Fos+ when an equivalent amount of sleep was preceded by SD. We conclude that, although sleep is necessary for cortical nNOS/NK1 neuron activation, the proportion of cells activated is dependent upon prior wake duration. [ABSTRACT FROM AUTHOR]

The aim of the current study was to compare mental health problems, resilience and family characteristics in adolescents with and without delayed sleep phase ( DSP) in a population-based sample. Data were taken from the youth@hordaland-survey, a large population-based study in Hordaland County in Norway conducted in 2012. In all, 9338 adolescents aged 16-19 years (53.5% girls) provided self-reported data on a wide range of instruments assessing mental health symptoms, including depression, anxiety, obsessive-compulsive behaviours, attention deficit hyperactive disorder ( ADHD) symptoms, perfectionism, resilience and sleep. Measures of socioeconomic status were also included. Three hundred and six adolescents (prevalence 3.3%) were classified as having DSP [according to the International Classification of Sleep Disorders-2 ( ICSD-2)] criteria. Adolescents with DSP reported higher levels of depression, anxiety and ADHD symptoms. Adolescents with DSP also exhibited significantly lower levels of resilience. The Cohen's d effect sizes ranged from small [obsessive-compulsive disorder ( OCD): d = 0.15] to moderate (inattention: d = 0.71). In the fully adjusted model, the significant predictors of DSP included inattention [odds ratio ( OR): 2.11], lack of personal structure ( OR: 2.07), low ( OR: 1.85) and high ( OR: 1.91) paternal education, parents not living together ( OR: 1.81), hyperactivity/inattention (OR: 1.71) and poorer family economy ( OR: 1.59). In conclusion, the high symptom load across a range of mental health measures suggests that a broad and thorough clinical approach is warranted when adolescents present with DSP. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate long-term trends in insomnia symptoms, tiredness and school performance among Finnish adolescents. A time-series from 1984 to 2011 was analysed from two large-scale survey studies, the Finnish School Health Promotion Study and the Health Behavior in School-Aged Children study. A total of 1 136 583 adolescents aged 11-18 years answered a standardized questionnaire assessing frequency of insomnia symptoms, tiredness and school performance. A clear approximately twofold increasing trend in insomnia symptoms and tiredness was found from the mid-1990s to the end of the 2000s. The increase was evident in all participating age groups and in both genders. After 2008, the increase seems to have stopped. Insomnia symptoms and tiredness were associated with lower school performance and they were more prevalent among girls (11.9 and 18.4%) compared to boys (6.9 and 9.0%, respectively). Unexpectedly, we also observed an increasingly widening gap in school performance between normally vigilant and chronically tired pupils. The underlying causes of these phenomena are unknown, but may concern changes in the broader society. The observed recent increasing trend in adolescents' sleep problems is worrisome: poor sleep quality has also been suggested to associate with clinical or subclinical mood or anxiety disorders and behavioural problems and predispose to sleep and psychiatric disorders later in life. Our results justify further studies and call for serious attention to be paid to adolescent's sleep in the Finnish educational system and society at large. [ABSTRACT FROM AUTHOR]

Those suffering insomnia symptoms generally report daytime impairments. However, research has not assessed whether this relationship holds on a nightly basis, despite the strongly held belief that a night of poor sleep impairs mood and functioning the following day. The objective of this study was to test this relationship in a group of older poor sleepers with insomnia symptoms compared with good sleepers. This study utilized a within-subjects design to investigate day-to-day subjective daytime functioning and its relation to the previous night's sleep. Seventeen older individuals (mean age: 67.5 years) were identified with a retrospective questionnaire and 2 weeks of sleep-wake diary to have poor sleep consistent with insomnia. Seventeen good sleepers (mean age: 67.8 years) were selected using the same measures. Participants reported their beliefs about sleep and daytime functioning on the Dysfunctional Beliefs and Attitudes about Sleep Scale ( DBAS-16). One week later they commenced a 14-day period of sleep-wake diaries and concurrent responses to a modified Daytime Insomnia Symptom Scale ( DISS). Results showed significant night-to-day covariation between sleep efficiency and daytime functioning for individuals with poor sleep ( r = 0.34), but not for good sleepers ( r = 0.08). Those poor sleepers who held this covariation belief most strongly were those who subsequently showed this night-to-day relationship the most strongly ( r = 0.56). This was not true for good sleepers. For those suffering insomnia, these findings demonstrate their belief that a poor sleep is followed by an impaired daytime, consistent with their experience. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea ( OSA) is more common in men than women. Body size is greater in males (sexual dimorphism), but large body habitus is associated with OSA for both genders. We speculated that male-female phenotypical convergence (reduced sexual dimorphism via identical phenotype acquisition) occurs with OSA and tested hypotheses: (1) phenotypical features pathogenic for OSA differ between OSA and healthy subjects irrespective of gender; and (2) such characteristics exhibit phenotypical convergence. Utilizing an existing database, we calculated male-female (group average) ratios for eight anthropometric and 33 surface cephalometric variables from 104 Caucasian OSA patients [72 males; apnea-hypopnea index (events h−1): males: 42.3 ± 24.7 versus females: 42.6 ± 26.1 ( P > 0.9)] and 85 Caucasian, healthy, non- OSA, community volunteers (36 males). Log-transformed data were analysed using a general linear model with post-hoc unpaired t-tests and significance at P < 0.0012 (Bonferroni multiple-comparison correction). OSA patients were older (56.9 ± 14.4 versus 38.0 ± 13.8 years), but there were no within-group gender-based age differences. All anthropometric variables (except height), plus cranial base width, mandibular breadth and retromandibular width diagonal were larger in gender-matched OSA versus healthy comparisons; thus satisfying hypothesis (1). Male-female ratios were mostly >1.0 across groups, but with no significant group × gender interactions no variable satisfied hypothesis (2). Thus, in this exploratory study, OSA patients had gender-common phenotypical differences to healthy subjects, but sexual dimorphism was preserved. Lack of complete phenotypical convergence may indicate gender-based critical phenotype-level attainment for OSA and/or gender-based OSA prevalence arises from factors other than those in this study. [ABSTRACT FROM AUTHOR]

The main purpose of the present analysis is to assess the influence of introducing early nasal continuous positive airway pressure ( nCPAP) treatment on cardiovascular recurrences and mortality in patients with a first-ever ischaemic stroke and moderate-severe obstructive sleep apnea (OSA) with an apnea-hypopnea index (AHI) ≥20 events h−1 during a 5-year follow-up. Patients received conventional treatment for stroke and were assigned randomly to the nCPAP group ( n = 71) or the control group ( n = 69). Cardiovascular events and mortality were registered for all patients. Survival and cardiovascular event-free survival analysis were performed after 5-year follow-up using the Kaplan-Meier test. Patients in the nCPAP group had significantly higher cardiovascular survival than the control group (100 versus 89.9%, log-rank test 5.887; P = 0.015) However, and also despite a positive tendency, there were no significant differences in the cardiovascular event-free survival at 68 months between the n CPAP and control groups (89.5 versus 75.4%, log-rank test 3.565; P = 0.059). Early n CPAP therapy has a positive effect on long-term survival in ischaemic stroke patients and moderate-severe OSA. [ABSTRACT FROM AUTHOR]

In 2010 the European Medicines Agency withdrew the indication of modafinil for the treatment of obstructive sleep apnea, shift work sleep disorder and for idiopathic hypersomnia ( IH). In uncontrolled studies, modafinil has been reported to be efficacious in the treatment of sleep disorders. We therefore performed a randomized, placebo-controlled study with the aim of proving the efficacy of modafinil treatment in these patients. Drug-free IH patients without long sleep according to ICSD2 criteria, age >18 years and disease duration >2 years were included. After a washout phase, patients at baseline received placebo or 100 mg modafinil in the morning and at noon over 3 weeks, followed by 1 week without medication. At each visit the Epworth Sleepiness Scale ( ESS) and Clinical Global Impression ( CGI) rating scale were performed. At baseline and on days 8 and 21 four Maintenance of Wakefulness Tests ( MWTs)/day or per day were performed. Patients kept a sleep-wake diary throughout the study. Between 2009 and 2011 three sleep centres recruited 33 participants. Compared to placebo, modafinil decreased sleepiness significantly and improved mean sleep latency in the MWT non-significantly. The CGI improved significantly from baseline to the last visit on treatment. The most frequent adverse events were headaches and gastrointestinal disorders; skin and psychiatric reactions were not reported. The number of reported naps and duration of daytime sleepiness decreased significantly. Total sleep time of nocturnal sleep was slightly reduced. The sleep diaries showed increases in feeling refreshed in the morning; the diurnal diaries showed significant improvement of performance and of exhaustion. Modafinil is an effective and safe medication in the treatment of IH. Adverse events are mild to moderate. [ABSTRACT FROM AUTHOR]

After stroke, the injured brain undergoes extensive reorganization and reconnection. Sleep may play a role in synaptic plasticity underlying stroke recovery. To test this hypothesis, we investigated topographic sleep electroencephalographic characteristics, as a measure of brain reorganization, in the acute and chronic stages after hemispheric stroke. We studied eight patients with unilateral stroke in the supply territory of the middle cerebral artery and eight matched controls. All subjects underwent a detailed clinical examination including assessment of stroke severity, sleep habits and disturbances, anxiety and depression, and high-density electroencephalogram examination with 128 electrodes during sleep. The recordings were performed within 10 days after stroke in all patients, and in six patients also 3 months later. During sleep, we found higher slow-wave and theta activity over the affected hemisphere in the infarct area in the acute and chronic stage of stroke. Slow-wave, theta activity and spindle frequency range power over the affected hemisphere were lower in comparison to the non-affected side in a peri-infarct area in the patients' group, which persisted over time. Conversely, in wakefulness, only an increase of delta, theta activity and a slowing of alpha activity over the infarct area were found. Sleep slow-wave activity correlated with stroke severity and outcome. Stroke might have differential effects on the generation of delta activity in wakefulness and sleep slow waves (1-8 Hz). Sleep electroencephalogram changes over both the affected and non-affected hemispheres reflect the acute dysfunction caused by stroke and the plastic changes underlying its recovery. Moreover, these changes correlate with stroke severity and outcome. [ABSTRACT FROM AUTHOR]

Diurnal sleep effects on consolidation of a complex, ecological valid gross motor adaptation task were examined using a bicycle with an inverse steering device. We tested 24 male subjects aged between 20 and 29 years using a between-subjects design. Participants were trained to adapt to the inverse steering bicycle during 45 min. Performance was tested before ( TEST1) and after ( TEST2) training, as well as after a 2 h retention interval ( TEST3). During retention, participants either slept or remained awake. To assess gross motor performance, subjects had to ride the inverse steering bicycle 3 × 30 m straight-line and 3 × 30 m through a slalom. Beyond riding time, we sophisticatedly measured performance accuracy (standard deviation of steering angle) in both conditions using a rotatory potentiometer. A significant decrease of accuracy during straight-line riding after nap and wakefulness was shown. Accuracy during slalom riding remained stable after wakefulness but was reduced after sleep. We found that the duration of rapid eye movement sleep as well as sleep spindle activity are negatively related with gross motor performance changes over sleep. Together these findings suggest that the consolidation of adaptation to a new steering device does not benefit from a 2 h midday nap. We speculate that in case of strongly overlearned motor patterns such as normal cycling, diurnal sleep spindles and rapid eye movement sleep might even help to protect everyday needed skills, and to rapidly forget newly acquired, interfering and irrelevant material. [ABSTRACT FROM AUTHOR]

Children's sleep problems are common and associated with increased risk for adjustment problems. We examined daily links between children's sleep and mood, using a daily diary method and actigraphy. We also tested children's daily mood as a mediator of relations among sleep and children's broader internalizing and externalizing symptoms. A community sample of 142 children (mean age = 10.69 years; 57% girls; 69% European American, 31% African American) and their parents participated. For 1 week, children wore actigraphs and parents completed a daily telephone interview about their child's mood. Following the week of actigraphy, mothers and fathers reported on their child's adjustment. Multi-level models indicated within-person relations between children's mood and subsequent sleep fragmentation (indicated by increased activity) and sleep latency, and between-person relations between sleep latency and subsequent mood on the next day. Significant indirect effects were found such that a more negative daily mood (aggregated across diary days) mediated relations between poor sleep efficiency and longer sleep latency and parent-reported internalizing and externalizing symptoms. Findings extend previous research by highlighting disruptions to children's daily mood as a potential mechanism linking sleep problems to children's mental health. [ABSTRACT FROM AUTHOR]

Discrepancy between subjective and objective measures of sleep is associated with insomnia and increasing age. Cognitive behavioural therapy for insomnia improves sleep quality and decreases subjective-objective sleep discrepancy. This study describes differences between older adults with insomnia and controls in sleep discrepancy, and tests the hypothesis that reduced sleep discrepancy following cognitive behavioural therapy for insomnia correlates with the magnitude of symptom improvement reported by older adults with insomnia. Participants were 63 adults >60 years of age with insomnia, and 51 controls. At baseline, participants completed sleep diaries for 7 days while wearing wrist actigraphs. After receiving cognitive behavioural therapy for insomnia, insomnia patients repeated this sleep assessment. Sleep discrepancy variables were calculated by subtracting actigraphic sleep onset latency and wake after sleep onset from respective self-reported estimates, pre- and post-treatment. Mean level and night-to-night variability in sleep discrepancy were investigated. Baseline sleep discrepancies were compared between groups. Pre-post-treatment changes in Insomnia Severity Index score and sleep discrepancy variables were investigated within older adults with insomnia. Sleep discrepancy was significantly greater and more variable across nights in older adults with insomnia than controls, P ≤ 0.001 for all. Treatment with cognitive behavioural therapy for insomnia was associated with significant reduction in the Insomnia Severity Index score that correlated with changes in mean level and night-to-night variability in wake after sleep onset discrepancy, P < 0.001 for all. Study of sleep discrepancy patterns may guide more targeted treatments for late-life insomnia. [ABSTRACT FROM AUTHOR]

Non-nucleoside reverse transcriptase inhibitors are important antiretroviral agents for the treatment of human immunodeficiency virus. Some non-nucleoside reverse transcriptase inhibitors, in particular efavirenz, have prominent effects on sleep, cognition and psychiatric variables that limit their tolerability. To avoid confounds due to drug-drug and drug-disease interactions, we assessed the effects of efavirenz in healthy volunteers on sleep, cognition and psychological endpoints during the first week of treatment. Forty healthy male subjects were randomized to receive placebo or efavirenz 600 mg nightly for 7 days after completion of a 3-day placebo run-in period. Treatment with efavirenz was associated with reduced time to sleep onset in the Maintenance of Wakefulness Test, an increase in non-rapid eye movement sleep, a large exposure-related decrease in sigma band spectral density and sleep spindle density during non-rapid eye movement sleep, and reduced performance on an attention switching task. Because efavirenz has been shown to have serotonin 2A receptor partial-agonist properties, we reasoned that antagonism of serotonin 2A receptor signalling in the thalamic reticular nucleus, which generates sleep spindles and promotes attention, may be responsible. Consistent with predictions, treatment of healthy volunteers with a single dose of a serotonin 2A receptor antagonist was found to significantly suppress sigma band spectral density in an exposure-related manner and modulated the overall spectral profile in a manner highly similar to that observed with efavirenz, consistent with the notion that efavirenz exhibits serotonin 2A receptor partial-agonist pharmacology in humans. [ABSTRACT FROM AUTHOR]

Short-term interval timing i.e., perception and action relating to durations in the seconds range, has been suggested to display time-of-day as well as wake dependent fluctuations due to circadian and sleep-homeostatic changes to the rate at which an underlying pacemaker emits pulses; pertinent human data being relatively sparse and lacking in consistency however, the phenomenon remains elusive and its mechanism poorly understood. To better characterize the putative circadian and sleep-homeostatic effects on interval timing and to assess the ability of a pacemaker-based mechanism to account for the data, we measured timing performance in eighteen young healthy male subjects across two epochs of sustained wakefulness of 38.67 h each, conducted prior to (under entrained conditions) and following (under free-running conditions) a 28 h sleep-wake schedule, using the methods of duration estimation and duration production on target intervals of 10 and 40 s. Our findings of opposing oscillatory time courses across both epochs of sustained wakefulness that combine with increasing and, respectively, decreasing, saturating exponential change for the tasks of estimation and production are consistent with the hypothesis that a pacemaker emitting pulses at a rate controlled by the circadian oscillator and increasing with time awake determines human shortterm interval timing; the duration-specificity of this pattern is interpreted as reflecting challenges to maintaining stable attention to the task that progressively increase with stimulus magnitude and thereby moderate the effects of pacemaker-rate changes on overt behavior. [ABSTRACT FROM AUTHOR]

Aim Viral respiratory infections and atopy have been implicated in the pathogenesis of adenotonsillar hypertrophy and obstructive sleep apnoea ( OSA), but the role of atopy is controversial. We aimed to test our hypothesis that atopy, expressed as physician-diagnosed eczema, was associated with adenotonsillar hypertrophy and OSA among children who snored. Methods Data on children who snored and were referred for polysomnography were reviewed. The primary outcome measures were adenotonsillar hypertrophy and OSA. Results We analysed data on 855 children with a mean age (±standard deviation) of 6.3 (±2.5) years and median obstructive apnoea-hypopnea index of 2.1 episodes per hour. Of the 855 subjects, 133 (15.6%) had physician-diagnosed eczema, 591 (69.1%) had adenoidal hypertrophy, 605 (70.8%) had tonsillar hypertrophy, 219 (25.6%) were obese and 470 (55%) had OSA. Eczema was not related to adenoidal or tonsillar hypertrophy after adjustment for gender and age, with odds ratios ( OR) of 1.00 (95% confidence interval 0.67-1.49; p = 0.98) and 0.88 (95% confidence interval 0.59-1.32; p = 0.54), respectively. Similarly, eczema did not affect OSA frequency after adjustment for adenoidal and tonsillar hypertrophy, obesity, gender and age, with an adjusted OR of 0.82 (0.56-1.21; p = 0.32). Conclusions Atopy was not related to adenotonsillar hypertrophy or OSA in children who snore. [ABSTRACT FROM AUTHOR]

Aim Impaired arousal from sleep has been implicated in sudden infant death syndrome ( SIDS). Sleeping in the prone position is a major risk factor for SIDS. Epidemiological studies have shown that pacifier use decreases the risk of SIDS, even when infants sleep prone. We examined spontaneous arousability in infants slept prone and supine over the first 6 months of life and hypothesised that spontaneous arousals would be increased in pacifier users, particularly in the prone position. Methods Healthy term infants (n = 30) were studied on three occasions over the first 6 months after birth. Spontaneous cortical arousals and subcortical activations were scored and converted into frequency per hour of sleep. Results There was no effect of pacifier use on total time spent sleeping or awake or the number of spontaneous awakenings at any age. There was also no effect of pacifier use on the frequency or duration of the total number of spontaneous arousals or on cortical arousals and subcortical activations. Conclusion Pacifier use did not alter infant spontaneous arousability at any of the three ages studied, in either the prone or supine sleeping position. Any preventative effect of pacifiers for SIDS may be through physiological mechanisms other than increased arousability. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recipients, however its long-term consequences have only rarely been investigated. Here, we hypothesized that the presence of OSA would be associated with higher risk of mortality and faster decline of graft function in kidney transplant recipients. In a prospective cohort study 100 prevalent kidney transplant recipients who underwent one-night polysomnography at baseline and were followed for a median 75 months. Generalized linear mixed-effects models and Cox regression models were used to assess the association between OSA and the rate of progression of chronic kidney disease(CKD) and mortality. The estimated slopes of estimated glomerular filtration rate(eGFR) in patients with and without OSA were compared using a two-stage model of eGFR change including only OSA as a variable. In this model patients with OSA (eGFR versus time was -0.93 ml/min/1.73 m2/yr(95%CI:-1.75 to-0.11) had a similar slope as compared to patients without OSA(eGFR versus time was -1.24 ml/min/1.73 m2/yr(95%CI: -1.67 to -0.81). In unadjusted Cox proportional regression analyses OSA was not associated with higher all-cause mortality risk (Hazard Ratio(HR) = 1.20; 95% Confidence Interval(CI): 0.50-2.85). No association was found between the presence of OSA and the rate of progression of CKD or all-cause mortality in prevalent kidney transplant recipients. [ABSTRACT FROM AUTHOR]

Objective Treatment-induced early menopause occurs in > 80% of premenopausal women diagnosed with breast cancer. This study explored the relationship between vasomotor symptoms (VMS), sleep and mood in women aged 40-51 years with non-metastatic breast cancer. Methods Cross-sectional study using validated questionnaires (Greene Climacteric scale and Hospital Anxiety and Depression Scale, HADS). Women ( n = 114) were recruited from the community and hospital outpatient clinics. Frequency determination and structural equation modeling (SEMod) were used to examine the relationship between the latent variables: VMS, anxiety, and depression, and the indicator variable: difficulty sleeping. Results Participants' mean age was 47 years and 94% became menopausal after breast cancer diagnosis. Difficulty sleeping was reported by 82% of women with 46% reporting (Likert scale) 'quite a bit/extremely'. Most women reported night sweats (77% of women: 47% reporting 'quite a bit/extremely') and hot flushes (84% of women: 50% reporting 'quite a bit/extremely'). HADS scores indicated clinically relevant depression and anxiety in 98% and 99% of women, respectively. SEMod revealed that VMS contributed to difficulty sleeping (standardized coefficient = 0.54; p < 0.001) and difficulty sleeping mediated the relationship between VMS and anxiety (standardized coefficient = 0.34; p = 0.03). However, difficulty sleeping did not have a significant direct impact on depression (standardized coefficient = −0.03; p = 0.8), although anxiety was a strong predictor of depression (standardized coefficient = 0.83; p = 0.015). Conclusions VMS, sleep and mood disturbance are commonly experienced by younger women with breast cancer. Using SEMod, we demonstrate for the first time that VMS may directly influence sleep in these women. VMS may have an indirect effect on mood, partly mediated by sleep difficulty. [ABSTRACT FROM AUTHOR]

Self-reports of long or short sleep durations have indicated an association with cardiovascular morbidity and mortality, but there are limited data evaluating their association with white matter hyperintensity volume ( WMHV), a marker of cerebral small vessel disease. We conducted a cross-sectional analysis of self-reported sleep duration to test for a correlation with white matter hyperintensities, measured by quantitative magnetic resonance imaging ( MRI), in the Northern Manhattan Study. We used multivariable linear regression models to assess associations between both short (<6 h) and long (≥9 h) sleep durations and log-transformed WMHV, adjusting for demographic, behavioural and vascular risk factors. A total of 1244 participants, mean age 70 ± 9 years, 61% women and 68% Hispanics were analysed with magnetic resonance brain imaging and self-reported sleep duration. Short sleep was reported by 23% ( n = 293) and long sleep by 10% ( n = 121) of the sample. Long sleep ( β = 0.178; P = 0.035), but not short sleep ( β = −0.053; P = 0.357), was associated with greater log- WMHV in fully adjusted models. We observed an interaction between sleep duration, diabetes mellitus and log- WMHV ( P = 0.07). In fully adjusted models, stratified analysis showed that long sleep duration was associated with greater WMHV only in those with diabetes ( β = 0.78; P = 0.0314), but not in those without diabetes ( β = 0.022; P = 0.2), whereas short sleep was not associated with white matter hyperintensities in those with or without diabetes. In conclusion, long sleep duration was associated with a greater burden of white matter lesions in this stroke-free urban sample. The association was seen mainly among those with diabetes mellitus. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to assess the sleep quality of tinnitus sufferers and to confirm the relationship between age, gender, tinnitus duration and tinnitus severity and sleep disturbances. Methods: Sixty tinnitus patients and 60 control subjects without tinnitus were included in this study. Age, gender, duration of tinnitus were listed on a chart. Tinnitus severity was measured by Tinnitus Handicap Inventory (THI) (for tinnitus group). Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. Results: The mean values of sleep efficiency, perceived sleep quality, daily disturbances for tinnitus group were significantly higher than control group (p=0.0001). Ageing in tinnitus sufferers deteriorated the sleep quality of the subjects. Analysis of the scores according to gender showed no significant differences. There was positive correlation between THI scores and the scores of sleep efficiency, perceived sleep quality and daily disturbances respectively (p=0.0001/r=0.830, p=0.0001/r=0.686, p=0.0001/r=0.713). Conclusions: Tinnitus not only have negative effects on social life but also have negative effects on sleep quality. [ABSTRACT FROM AUTHOR]

A consistent body of evidence suggests that cognitive factors play key roles in the development of insomnia. Here we investigate the links between sleep quality and dysfunctional beliefs about sleep, on one side, and difficulties in emotion regulation, on the other. We also assess whether poor sleepers have more difficulties in regulating their emotions compared to good sleepers. One hundred thirty-three adults, aged 26.14±7.61 years, recruited from the general community, completed a battery of scales hosted online. Our results indicate that individuals complaining of poorer sleep have problems in accepting their own emotions and engaging in goaldirected behaviours when they experience negative emotions. They also show greater difficulties in controlling their impulse when experiencing negative emotions and in understanding their own emotions. Sleep quality was significantly, negatively and moderately linked with difficulties in emotion regulation. Our findings support future research in larger and diverse samples in both cross-sectional and longitudinal studies in order to clarify the interplay of sleep and emotions. [ABSTRACT FROM AUTHOR]

Work in animals and humans has suggested the existence of a slow wave sleep (SWS)-promoting/electroencephalogram (EEG)-synchronizing center in the mammalian lower brainstem. Although sleep-active GABAergic neurons in the medullary parafacial zone (PZ) are needed for normal SWS, it remains unclear whether these neurons can initiate and maintain SWS or EEG slow-wave activity (SWA) in behaving mice. We used genetically targeted activation and optogenetically based mapping to examine the downstream circuitry engaged by SWS-promoting PZ neurons, and we found that this circuit uniquely and potently initiated SWS and EEG SWA, regardless of the time of day. PZ neurons monosynaptically innervated and released synaptic GABA onto parabrachial neurons, which in turn projected to and released synaptic glutamate onto cortically projecting neurons of the magnocellular basal forebrain; thus, there is a circuit substrate through which GABAergic PZ neurons can potently trigger SWS and modulate the cortical EEG. [ABSTRACT FROM AUTHOR]

Background Recent investigation has demonstrated that approximately 75% of patients with medically refractory chronic rhinosinusitis (CRS) report abnormal sleep quality, with strong correlation between worse sleep quality and more severe CRS disease severity. It remains unknown whether the treatment effect of endoscopic sinus surgery (ESS) for CRS results in appreciable sleep quality improvements. Methods Adult patients (aged ≥18 years) with a current diagnosis of recalcitrant chronic rhinosinusitis (CRS), who voluntarily elected ESS as the next treatment modality (n = 301), were prospectively evaluated within 4 academic, tertiary care centers using treatment outcome instruments: the Rhinosinusitis Disability Index, the 22-item Sinonasal Outcome Test, the 2-item Patient Health Questionnaire, and the Pittsburgh Sleep Quality Index (PSQI) both before and after ESS. Results Seventy-two percent (72%) of patients with CRS were found to have poor sleep (PSQI > 5) at baseline with a mean (standard deviation) global PSQI score of 9.4 (4.6). Surgery improved overall mean global PSQI scores (by 2.2 points), and all 7 subdomain scores of the PSQI. Similarly, the odds of good sleep quality (PSQI ≤ 5) in patients treated with sinus surgery increased significantly (odds ratio [OR] 5.94; 95% confidence interval [CI], 3.06 to 11.53; p < 0.001). Stepwise multivariate linear regression found that acetylsalicylic acid (ASA) intolerance (β [standard error], −1.94 [0.93]; 95% CI, −3.77 to −0.11; p = 0.038), history of prior sinus surgery (β [standard error], 1.10 (0.54); 95% CI, 0.03 to 2.16; p = 0.044), and frontal sinusotomy (β [standard error], −1.03 [0.62]; 95% CI, −2.26 to 0.20; p = 0.099) were found to significantly associate with improvement in PSQI sleep scores. Conclusion Among patients with CRS, reduced sleep quality, poor disease-specific quality of life, and greater disease severity were improved following ESS. [ABSTRACT FROM AUTHOR]

Sleep disordered breathing in children ranges from snoring, which has a prevalence of 12%, to obstructive sleep apnea (OSA) syndrome, which has a prevalence of 2?3% in the general population [1]. The underlying causes of pediatric OSA are extremely complex. There are bony structural influences, as seen in craniofacial abnormalities, and soft tissue abnormalities, such as a large tongue, redundant soft tissue, or compliance/collapsibility issues. In some groups, such as those with Down syndrome, a combination of these factors comes into play. [ABSTRACT FROM AUTHOR]

Sleep quality and duration are increasingly recognised as being important prognostic parameters in the assessment of an individual's health. However, reliable non-invasive long-term monitoring of sleep in a non-clinical setting remains a challenging problem. This paper describes the validation of a novel under mattress pressure sensing sleep monitoring modality that can be seamlessly integrated into existing home environments and provides a pervasive and distributed solution for monitoring long-term changes in sleep patterns and sleep disorders in adults. 410 minutes of concomitant Under Mattress Bed Sensor (UMBS) and strain gauge data were analysed from eight healthy adults lying passively. In this analysis, customised respirations rate detection algorithms yielded a mean difference of -0.12 breaths per five minutes and a mean percentage error (MPE) of 0.16% when the sensor was placed beneath the mattress. 1,491 minutes of UMBS and video data were recorded simultaneously from four participants in order to assess the movement detection efficacy of customised UMBS algorithms. These algorithms yielded accuracies, sensitivities and specificities of over 90% when compared to a video-based movement detection gold standard. A reduced data set (267 minutes) of wrist actigraphy, the gold standard ambulatory sleep monitor, was recorded. The UMBS was shown to outperform the movement detection ability of wrist actigraphy and has the added advantage of not requiring active subject participation. [ABSTRACT FROM AUTHOR]

Purpose In the present study, we aimed to investigate the effects of chemotherapy-induced peripheral neurotoxicity (CIPN) on psychological distress and sleep quality in cancer patients. Methods A total of 706 cancer patients were interviewed for the study. In the 4th week of treatment, patient CIPN was measured using the Patient Neurotoxicity Questionnaire (PNQ ) . The sleep quality and psychological distress of patients were measured using the Pittsburgh Sleep Quality Index (PSQI) , the Distress Thermometer (DT) , and the Hospital Anxiety and Depression Scale (HADS). Multiple logistic regression was applied to determine the independent effects of CIPN on psychological distress and sleep disturbance in the patients. Results These correlation coefficients were obtained: 0.387 (P < 0.0001) between the PNQ total score and the DT score, 0.386 (p < 0.0001) between the PNQ total score and the HADS Depression score, 0.379 (p < 0.0001) between the PNQ total score and the HADS Anxiety score, and 0.399 (p < 0.0001) between the PNQ total score and the PSQI global score. The prevalence rates of distress, depression, anxiety, and poor sleep quality in the five PNQ grades were statistically significantly different (p < 0.0001). After controlling for age, sex, education level, social supports, fatigue, disease stage, and tumour site, the PNQ grades were found to be associated with depression (p < 0.0001), anxiety (p < 0.0001), and poor sleep quality (p < 0.0001). Conclusions Chemotherapy-induced peripheral neurotoxicity negatively affects psychological distress and sleep quality in cancer patients treated with chemotherapy. High PNQ grades were significantly associated with poor psychological status and sleep quality. Our results emphasize the importance of assessing peripheral neuropathies during chemotherapy and of adjusting treatment plans based on assessment results. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationship between sleep disturbance in children with liver transplants and parent and family health-related quality of life (HRQOL). Method 47 parents of children with liver transplants completed measures of child sleep and family HRQOL. Relationships between sleep and HRQOL and differences in HRQOL between groups with scores above and below the cutoff on a pediatric sleep measure were examined. Results Parents endorsed higher rates of sleep-related breathing disorder (SRBD) and restless legs syndrome and periodic limb movements during sleep (RLS/PLMS) and lower HRQOL compared with published data. Significant correlations were found between SRBD and RLS/PLMS and HRQOL, and significant group differences in HRQOL were found between groups above and below the cutoff for behavior problems and RLS/PLMS. Conclusion There are significant relationships between symptoms of SRBD and RLS/PLMS in children with liver transplants and family HRQOL. Behavior problems may account for these strong relationships. [ABSTRACT FROM AUTHOR]

The search activity concept proposed a new classification of the types of behavior according to the adaptation to the environment. In this article I have explained the story of the creation of this concept and discuss the probability forecasts of the outcomes of activity in different types of behavior and in REM sleep dreams. The direction of search can be changed if the outcome of activity does not correspond to the forecast. Stereotyped behavior uses habitual skills and algorithms with a definite forecast of the results. Chaotic (panic) behavior does not include monitoring of the results of activity. It determines the unreasonable fluctuations of the direction of activity independent of its outcome without probability forecast. Finally after painful failures it can lead to the renunciation of activity where the forecast of the positive results of activity is on the zero level. In REM sleep dreams subject is separated from the surrounding environment and the "failures" of the virtual activity are not dangerous for the subject. The process of activity by itself is more important than its direction and its outcome. For this reason search activity in dreams imitates chaotic activity in wakefulness however without its negative outcome and after awakening subject is ready to perform normal search activity. [ABSTRACT FROM AUTHOR]

Though obstructive sleep apnea hypopnea syndrome (OSAHS) and metabolic syndrome (MS) are correlated; the contributing factors for the occurrence of MS in Chinese snorers remain largely undefined. We aimed to investigate the associated pathogenesis of coexistence of OSAHS and MS in Chinese snorers. A total of 144 Chinese habitual snorers were divided into 3 groups, the control group (simple snorers) (n 5 36), the mild OSAHS group (n 5 52) and the moderate-to-severe OSAHS group (n 5 56). The incidence of MS in the moderate-to-severe OSAHS group (26.8%) was significantly higher than that in the control group (8.3%), the mild OSAHS group (11.1%) and all the OSAHS patients (19.45%) (all P, 0.05). Homeostatic model assessment (HOMA) index and proinsulin (PI) were negatively correlated with nocturnal meanSpO2 and miniSpO2. Meanwhile, nocturnal SpO2 were negatively correlated with body mass index, waist and neck circumferences and diastolic blood pressure, but positively correlated with total cholesterol and high-density lipoprotein cholesterol. The study indicated that in Chinese snorers, moderate- to-severe OSAHS was closely associated with MS via nocturnal hypoxemia. [ABSTRACT FROM AUTHOR]

The thalamic synapses relay peripheral sensory information to the cortex, and constitute an important part of the thalamocortical network that generates oscillatory activities responsible for different vigilance (sleep and wakefulness) states. However, the modulation of thalamic synaptic transmission by potential sleep regulators, especially by combination of regulators in physiological scenarios, is not fully characterized. We found that somnogen adenosine itself acts similar to wake-promoting serotonin, both decreasing synaptic strength as well as short-term depression, at the retinothalamic synapse. We then combined the two modulators considering the coexistence of them in the hypnagogic (sleep-onset) state. Adenosine plus serotonin results in robust synergistic inhibition of synaptic strength and dramatic transformation of short-term synaptic depression to facilitation. These synaptic effects are not achievable with a single modulator, and are consistent with a high signal-to-noise ratio but a low level of signal transmission through the thalamus appropriate for slow-wave sleep. This study for the first time demonstrates that the sleep-regulatory modulators may work differently when present in combination than present singly in terms of shaping information flow in the thalamocortical network. The major synaptic characters such as the strength and short-term plasticity can be profoundly altered by combination of modulators based on physiological considerations. [ABSTRACT FROM AUTHOR]

Intermittent hypoxia (IH) is most often thought of for its role in morbidity associated with sleep-disordered breathing, including central nervous system pathology. However, recent evidence suggests that the nervous system fights back in an attempt to minimize pathology by increasing the expression of growth/trophic factors that confer neuroprotection and neuroplasticity. For example, even modest ("low dose") IH elicits respiratory motor plasticity, increasing the strength of respiratory contractions and breathing. These low IH doses upregulate hypoxia-sensitive growth/trophic factors within respiratory motoneurons but do not elicit detectable pathologies such as hippocampal cell death, neuroinflammation, or systemic hypertension. Recent advances have been made toward understanding cellular mechanisms giving rise to IH-induced respiratory plasticity, and attempts have been made to harness the benefits of low-dose IH to treat respiratory insufficiency after cervical spinal injury. Our recent realization that IH also upregulates growth/trophic factors in nonrespiratory motoneurons and improves limb (or leg) function after incomplete chronic spinal injuries suggests that IH-induced plasticity is a general feature of motor systems. Collectively, available evidence suggests that lowdose IH may represent a safe and effective treatment to restore lost motor function in diverse clinical disorders that impair motor function. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate subjective sleep quality, day-time sleepiness, prevalence of substance use, satisfaction with life among residents at our institute. To evaluate association of sleep qualitywith satisfaction with life and day-time sleepiness. To compare the findings between residents in clinical and para-clinical departments. Materials and Methods: Eighty-four residents filled questionnaires to obtain socio-demographic information and use of substance (s). Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Satisfaction With Life scale (SWLS) were also used. Association between sleep quality and sleepiness and satisfaction with life was evaluated. From the data collected, comparisons were made between the clinical and para-clinical department residents. Results: A significant number of residents belonging to the clinical faculty were poorsleepers; reported high levels of abnormal day-time sleepiness and less satisfaction with life compared to residents in para-clinical faculties. The differences in correlation between sleepiness and satisfaction with life with sleep quality among the two groups were not found to be significant. A larger percentage of clinical residents reported use of at least one substance during the residency period compared to the para-clinical residents. Conclusions: Poor sleep quality is perceived greatly by the resident doctors in our public hospital, especially among clinical faculties. Interventions are thus necessary in order to ensure adequate sleep among them. [ABSTRACT FROM AUTHOR]

Research suggests that a sensation of floating prior to sleep may be indicative of several sleep-related phenomena such as sleep paralysis, hypnagogic imagery, and out-of-body experiences (OBEs). Previous research into OBEs in particular has been limited in considering the broad range of tactile, auditory, and visual phenomena reported by individuals prior to sleep which relate to a floating sensation that tends to precede an OBE. In the present study, 178 participants were surveyed regarding their experience of a floating sensation prior to sleep as part of a larger OBE questionnaire. A thematic analysis was conducted in order to determine commonalities in floating sensations prior to sleep reported among participants. Themes in reports of tactile and emotional content during a floating sensation were noted. Tactile sensations of feeling light or weightless, body detachment or loss of physical sensation, sensations of flying and sensations of falling were most common. Emotions relevant to a sense of floating were reported as being negative, positive, or associated with a feeling of freedom. A number of the floating sensations reported prior to sleep overlapped with common descriptions of OBEs found in literature, while others did not. Implications are discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Linguistic analysis of dream reports. [•] Phenomenology of dream consciousness. [•] Differences between the phenomenology of REM sleep and of hypnagogic hallucinations. [•] Level of dreamer action. [ABSTRACT FROM AUTHOR]

Sleep behavior remains one of the most enigmatic areas of life. The unanswered questions range from 'why do we sleep?' to 'how we can improve sleep in today's society?' Identification of mutations responsible for altered circadian regulation of human sleep lead to unique opportunities for probing these territories. In this review, we summarize causative circadian mutations found from familial genetic studies to date. We also describe how these mutations mechanistically affect circadian function and lead to altered sleep behaviors, including shifted or shortening of sleep patterns. In addition, we discuss how the investigation of mutations can not only expand our understanding of the molecular mechanisms regulating the circadian clock and sleep duration, but also bridge the pathways between clock/sleep and other human physiological conditions and ailments such as metabolic regulation and migraine headaches. [ABSTRACT FROM AUTHOR]

The present study represents an attempt, in the context of the following questions, to examine the hypnagogic hallucinations experienced by one person over several years: (a) Do the hallucinations occur randomly, or follow some kind of trend or pattern? (b) Can the content of the hypnagogic experiences be categorized in types, and how do these relate to existing literature? (c) How do these types change or develop across the years? To find answers to the questions posed, first, the period of time was measured between consequent diary entries. Second, the actual material recorded by the dreamer was assessed using 14 criteria. These assessments were then subject to a P-Technique Factor Analysis. The Factor Analysis extracted four significant factors, labeled "Unusual Bodily Experiences, .... The Intruder," "Incubus," and "Fear." The extracted Factors are well supported by the results of similar studies dealing with random samples. Theoretical implications and consequences of the practical work will be discussed. The present investigation was inspired by the fact that much of the existing research into the topic is based on cross-sectional studies, which are inherently unable to account for individual temporal development in the hypnagogic phenomena in question. [ABSTRACT FROM AUTHOR]