Daily distribution of sleep states in the jackdaw, Corvus monedula

Polygraphic and behavioral studies of the jackdaws Corvus monedula have revealed a strong influence of the natural day-night cycle on their daily wakefulness-sleep activity. The jackdaws were behaviorally active during the light part of the photoperiod. The daily distribution of slow wave sleep (SWS) was symmetric and that of paradoxical sleep (PS) was asymmetric. The amount of PS was greater in the second half of the night than in the first. Short and intermediate length episodes occurred almost homogeneously throughout the night. The longest sleep episodes clustered toward the middle part of the night and did not occur in the periods following onset of sleep and before the end of sleep.     

Auditory deprivation modifies biological rhythms in the golden hamster

To assess to what extent auditory sensory deprivation affects biological rhythmicity, sleep/wakefulness cycle and 24 h rhythm in locomotor activity were examined in golden hamsters after bilateral cochlear lesion. An increase in total sleep time as well as a decrease in wakefulness (W) were associated to an augmented number of W episodes, as well as of slow wave sleep (SWS) and paradoxical sleep (PS) episodes in deaf hamsters. The number of episodes of the three behavioural states and the percent duration of W and SWS increased significantly during the light phase of daily photoperiod only. Lower amplitudes of locomotor activity rhythm and a different phase angle as far as light off were found in deaf hamsters kept either under light-dark photoperiod or in constant darkness. Period of locomotor activity remained unchanged after cochlear lesions. The results indicate that auditory deprivation disturbs photic synchronization of rhythms with little effect on the clock timing mechanism itself.     

Evolutionary aspects of sleep–wake cycle development in vertebrates (Modern state of the I.G. Karmanova’s sleep evolution theory)

The genetic basis of rest–activity circadian alternation in animal behavior is considered in the evolutionary range from bacteria to mammals. We scrutinize various concepts of sleep development in the animal world evolution as well as the I.G. Karmanova’s theory of the sleep–wake cycle evolution in vertebrates, beginning from wakefulness–primary sleep (or protosleep) in fish and amphibians through wakefulness–intermediate sleep in reptiles to wakefulness–slow wave sleep (SWS) and paradoxical sleep (PS) in birds and mammals. Primary sleep is represented by the three major sleep-like immobility states: catalepsy, catatonia and cataplexy. The main behavioral, somatovegetative and neurophysiological characteristics of primary sleep and the ancient activation pattern during primary sleep are described. The issues of which of these sleep manifestations are homologous to SWS, PS, hibernation and stress response are discussed. In conclusion, the general diagram of sleep evolution in vertebrates is presented, and the I.G. Karmanova’s contribution to evolutionary somnology is highlighted.     

中缝背核5-羟色胺能神经元在睡眠调节中的作用研究

目的：研究中缝背核(DRN)5-羟色胺(5-HT)能神经元在睡眠中的调节作用。方法：运用脑立体定位、核团微量注射和多导睡眠描记(PSG),观察DRN 5-HT能神经元对大鼠睡眠的影响。结果：DRN微量注射谷氨酸钠(L-Glu),大鼠睡眠减少,特别是深慢波睡眠(SWS2)明显减少,觉醒(W)增加;DRN微量注射海人酸(KA)和对氯苯丙氨酸(PCPA),大鼠SWS2和异相睡眠(PS)增加,W减少。结论：DRN 5-HT能神经元参与睡眠的调节,兴奋DRN 5-HT能神经元睡眠时间减少,抑制DRN 5-HT能神经元则具有促进睡眠的作用。     

Sleep pattern in the starling (Sturnus vulgaris)

Electrographic and behavioural observations were conducted on two male and two female captive starlings (Sturnus vulgaris) under natural illumination conditions during autumn. Polygraphically sleep and wakefulness of starling were similar to those of other birds. Starling's total sleep (TS) and slow wave sleep (SWS) lasted 39.0 +/- 1.4% and 38.3 +/- 1.7% of the 24-h period respectively. Paradoxical sleep (PS) was 1.8 +/- 0.2% of the total sleep time. The mean durations individual of TS, SWS and PS episodes were 6.8 +/- 0.2 min, 5.0 +/- 1.0 min and 18 +/- 3 s respectively. The daily percentage of SWS was correlated with the mean episode duration while that of PS was correlated with the number of episodes rather than with the mean episode duration. Starling females spent in sleep a greater percentage of the 24-h period than males.     

Distribution of sleep and wakefulness in 24-h light-dark cycles in the juvenile and adult magpie, Pica pica

The daily organization of sleep and wakefulness was examined electrographically under natural conditions in captive juvenile and adult magpies, Pica pica. Electrographic indices of sleep in the magpie were found to be similar to those of other avian species. The daily amount of TS in juveniles was 17% greater than in adults. The amount of paradoxical sleep (PS) in adults was one-fifth that of juveniles. In adults sleep was confined to darkness, while in juveniles it also occurred during the light period. SWS in adults was almost constant, while PS slightly increased across the night. No systematic trends were observed in juveniles. In both groups of birds, the longest sleep episodes appeared around midnight.     

侧脑室注射促甲状腺激素释放激素对大鼠睡眠—觉醒的影响

采用多导睡眠描记术研究了例脑室注射促甲状腺激素释放激素(TRH)对正常大鼠和去甲状腺大鼠睡眠-觉醒的影响。在正常大鼠,TRH引起觉醒增加,浅慢波睡眠(SWS_1)、深慢波睡眠(SWS_2)和总睡眠时间(TST)均减少,异相睡眠(PS)消失,SWS_1、SWS_2和PS的潜伏期均显著延长,给药后立即产生效应并在1h内达高峰。去甲状腺对大鼠的睡眠-觉醒无明显影响,注射TRH后引起的效应与正常大鼠相似。结果提示TRH有促进大鼠觉醒的作用,对各睡眠时相均有抑制作用,其作用部位可能在下丘脑以外的中枢结构。     

Effects of electrolytic lesion of hypothalamic paraventricular nucleus and its related areas on the sleep waking cycle in the cat

In order to study putative hypothalamic mechanisms of sleep waking cycle regulation we destroyed, by electrolytic coagulation, a large part of the medial hypothalamus overlapping the paraventricular nucleus in 6 adult cats. We never observed any modification of light slow wave sleep. Three of the six cats presented no paradoxical sleep (PS) impairment, despite an almost total destruction of neurophysin-immunoreactive cells of PVN in two cats and marked signs of diabetes insipidus in the third. Further, in the other three animals a statistically significant decrease of daily quantities of PS and deep slow wave sleep (SWS2) were related to an extensive destruction of the anterior hypothalamic area. These results suggest lack of influence of the PVN in sleep regulation and an involvement of the anterior hypothalamus in the onset of SWS2 and PS.     

Sleep pattern in the rook, Corvus frugilegus

In the rook, Corvus frugilegus, electrographic and behavioural correlates of sleep and wakefulness have been determined under natural lighting conditions. Slow wave sleep (SWS) was characterized by high amplitude slow EEG activity, low neck EMG, and behavioural inactivity. Paradoxical sleep (PS) was characterized by low amplitude fast EEG activity and inconsistent decrease in EMG. PS episodes always commenced with head downward. Several eye movements occurred activity were present. The rook spent in sleep 31.8% of the 24-h period. PS however, eye movements, high tonic neck EMG activity, and behavioural activity were present. The rook spent in sleep 31.8% of the 24-h period. PS constituted 1.8% of total sleep, while the rest of total sleep was occupied by SWS. On the average, episodes of SWS and PS lasted 10.8 min and 24 s respectively. The daily percentage of SWS was highly correlated with the mean episode duration. PS amount was better correlated with the number of episodes than with their mean duration. Our data suggest that over-short period of recovery from surgery and adaptation with implanted electrodes could lead to underestimation of sleep duration in rook.     

Circadian rhythms of slow-wave sleep and paradoxical sleep are in opposite phase in genetically hypoprolactinemic rats

In eleven genetically hypoprolactinemic rats (IPL nude rats) and five control rats (OFA), the sleep-waking cycle was continuously registered for 14 days at two ambient temperatures. At 23 degrees C, the slow wave sleep (SWS) duration of IPL rats was significantly higher (+6.8%, t = 5.4, p less than 0.001) than that of control rats, while the paradoxical sleep (PS) duration was lowered by 31.8% (t = 9.4, p less than 0.001). The circadian rhythm of PS disappeared while that of SWS persisted unchanged. At 30 degrees C, both sleep durations reached the level of control rats. The circadian rhythm of PS was however completely reversed: the PS acrophase was at 01 h while that of SWS was at 12 hrs. This first observation of spontaneous dissociation of the two states of sleep supports the hypothesis of two distinct circadian clocks, one for SWS, another for PS. It is suggested that hypothalamic prolactin and/or other still unknown genetic alterations might be responsible for the observed change in the PS circadian rhythm.     

Chronic Upper Airway Obstruction Induces Abnormal Sleep/Wake Dynamics in Juvenile Rats

Objectives

Conventional scoring of sleep provides little information about the process of transitioning between vigilance-states. We used the state space technique to explore whether rats with chronic upper airway obstruction (UAO) have abnormal sleep/wake states, faster movements between states, or abnormal transitions between states.

Design

The tracheae of 22-day-old Sprague-Dawley rats were surgically narrowed to increase upper airway resistance with no evidence for frank obstructed apneas or hypopneas; 24-h electroencephalography of sleep/wake recordings of UAO and sham-control animals was analyzed using state space technique. This non-categorical approach allows quantitative and unbiased examination of vigilance-states and state transitions. Measurements were performed 2 weeks post-surgery at baseline and following administration of ritanserin (5-HT2 receptor antagonist) the next day to stimulate sleep.

Measurements and Results

UAO rats spent less time in deep (delta-rich) slow wave sleep (SWS) and near transition zones between states. State transitions from light SWS to wake and vice versa and microarousals were more frequent and rapid in UAO rats, indicating that obstructed animals have more regions where vigilance-states are unstable. Ritanserin consolidated sleep in both groups by decreasing the number of microarousals and trajectories between wake and light SWS, and increasing deep SWS in UAO.

Conclusions

State space technique enables visualization of vigilance-state transitions and velocities that were not evident by traditional scoring methods. This analysis provides new quantitative assessment of abnormal vigilance-state dynamics in UAO in the absence of frank obstructed apneas or hypopneas.     

Study of sleep of shift workers with alternating schedules: adaptation and recovery in case of rapid shift rotation (3-4 days) (author's transl)

An electroencephalographic study of the sleep of shift workers (3 x 8) was performed in a French oil refinery. The recordings of diurnal sleep showed: a severe disorganization of the first day sleep (very short duration, decrease of PS and SWS in absolute amount); a trend towards better sleep characteristics (duration, PS and SWS amount) through the day-sleep period. Recovery night sleep appeared different when following curtailed night sleep (morning shift) and when following curtailed day sleep (night shift). Nocturnal sleep following immediately the diurnal sleep shows only partly the characteristics of a real recovery. Thus there seems to be a beginning adaptation to schedule reversal. This result supports a rapid shift alternation (3-4 days) which restrains both the cumulated sleep deficit and the adaptation to schedule reversal.     

Opposite variations of extracellular concentrations of 5-hydroxyindoleacetic acid (5-HIAA) measured by voltammetry of axonal terminals and cell bodies of the dorsal raphe nucleus through the sleep-wake cycle

Differential pulse voltammetry was used for 5-hydroxyindoleacetic acid (5-HIAA) detection in the rat caudate (n. Cd) and Raphe Dorsalis (n. RD) nuclei, in chronic experimental conditions. In the anterior and ventral part of n. RD, large increases in the extracellular concentrations of 5-HIAA were reported during slow wave sleep (SWS) and paradoxical sleep (PS) whereas a decrease occurred during waking. These variations could reflect the dendritic release of serotonin. In n. Cd, opposite variations of the extracellular concentrations of 5-HIAA were observed i.e. increase during waking state and decrease during SWS and PS.     

基底外侧杏仁核对睡眠-觉醒的调节作用

采用多道睡眠描记方法,观察了基底外侧杏仁核在睡眠－觉醒调节中的作用。结果发现,电损毁双侧ＢＬＮ引起慢波睡眠和快波睡眠增加,觉醒减少;在双侧ＢＬＮ内注射选择性损毁神经元胸体剂量的红藻氨酸引起双相效应,注射ＫＡ后第１天出现失眠,自第３天开始,ＳＷＳ增多,Ｗ减少,但ＰＳ无显著变化。     

Differential Associations of Early- and Late-Night Sleep with Functional Brain States Promoting Insight to Abstract Task Regularity

Background

Solving a task with insight has been associated with occipital and right-hemisphere activations. The present study tested the hypothesis if sleep-related alterations in functional activation states modulate the probability of insight into a hidden abstract regularity of a task.

Methodology

State-dependent functional activation was measured by beta and alpha electroencephalographic (EEG) activity and spatial synchronization. Task-dependent functional activation was assessed by slow cortical potentials (SPs). EEG parameters during the performance of the Number Reduction Task (NRT) were compared between before sleep and after sleep sessions. In two different groups, the relevant sleep occurred either in the first or in the second half of the night, dominated by slow wave sleep (SWS) or by rapid eye movement (REM) sleep.

Principal Findings

Changes in EEG parameters only occurred in the early-night group, not in the late-night group and indicated occipital and right-hemisphere functional alterations. These changes were associated with off-line consolidation of implicit task representations and with the amount of SWS but they did not predict subsequent insight. The gain of insight was, however, independently associated with changes of spectral beta and alpha measures only in those subjects from the two sleep groups who would subsequently comprehend the hidden regularity of the task. Insight-related enhancement of right frontal asymmetry after sleep did not depend on sleep stages.

Significance

It is concluded that off-line restructuring of implicit information during sleep is accompanied by alterations of functional activation states after sleep. This mechanism is promoted by SWS but not by REM sleep and may contribute to attaining insight after sleep. Original neurophysiologic evidence is provided for alterations of the functional activation brain states after sleep. These alterations are associated with a decrease in controlled processing within the visual system and with an increase in the functional connectivity of the right hemisphere, and are supported by SWS in the first half of the night.     

Circadian Eating and Sleeping Patterns in the Night Eating Syndrome

Objective: To compare the eating and sleep‐wake patterns of persons with the night eating syndrome (NES) with those of matched control subjects. Research Methods and Procedures: Forty‐six overweight/obese NES subjects (mean age 43.3 ± 9.8 years; 32 women) and 43 similar controls (mean age 39.0 ± 11.0 years; 28 women) wore wrist actigraphs for 7 days and completed sleep and food diaries at home. Results: There was no difference between the total energy intake of the NES and the control subjects, but the pattern of energy intake differed greatly. Relative to control subjects, the temporal pattern of food intake of night eaters was delayed. Food intake after the evening meal, as a proportion of the 24‐hour intake, was more than 3‐fold greater in NES subjects than in controls (34.6 ± 10.1% vs. 10.0 ± 6.9%, p = 0.001). NES subjects had sleep onset, offset, and total sleep duration times comparable with those of controls. NES subjects reported more nocturnal awakenings than did controls (1.5 ± 1.0 per night vs. 0.5 ± 0.5; p < 0.001), and their actigraphically monitored arousals occurred earlier during sleep (at 128 minutes after sleep onset vs. 193 minutes, p = 0.01). NES subjects consumed food on 74% of the awakenings vs. 0% for the controls. Discussion: The pattern of cumulative energy intake of the night eaters suggests a phase delay in energy consumption relative to sleep‐wake times. NES may involve a dissociation of the circadian control of eating relative to sleep.     

Study of sleep in a walrus

Several behavioral and physiological adaptations have been developed in evolution of Pinnipeds allowing them to sleep both on land and in water. To date sleep has been examined in detail in eared and true seals (the families of Otariidae and Phocidae). The aim of this study was to examine sleep in another semiaquatic mammal — the walrus, which is the only extant representative of the family Odobenidae. Slow wave and paradoxical sleep (SWS and PS) in the examined walrus (2 year old female, weight 130 kg) averaged 19.4 ± 2.0 and 6.9 ± 1.1% of 24-h when on land, and 20.5 ± 0.8% of 24-h and 1.1 ± 0.6% when in water, respectively. The average duration of PS episode was 6.4 ± 0.6 min (maximum 23 min) when on land and 1.8 ± 0.1 min (maximum 3.3 min) when in water. In water, sleep occurred predominantly while the walrus submerged and lay on the bottom of the pool (89% of total sleep time). The walrus usually woke up while emerging to the surface for breathing. Most often EEG slow waves developed synchronously in both cortical hemispheres (90% of SWS time when on land and 97% when in water). Short episodes of interhemispheric EEG asymmetry usually coincided with brief opening of one eye. The pattern of sleep in the walrus was similar to the pattern of sleep in the Otariidae seals while on land (predominantly bilateral SWS, accompanied by regular breathing) and to the pattern of sleep in the Phocidae while in water (sleep during apneas both in depth and at the surface, interrupted by brief arousal when emerging for breathing).     

Low-frequency rhythmic electrocutaneous hand stimulation during slow-wave night sleep: Physiological and therapeutic effects

Neocortical EEG slow wave activity (SWA) in the delta frequency band (0.5–4.0 Hz) is a hallmark of slow wave sleep (SWS) and its power is a function of prior wake duration and an indicator of a sleep need. SWS is considered the most important stage for realization of recovery functions of sleep. Possibility of impact on characteristics of a night sleep by rhythmic (0.8–1.2 Hz) subthreshold electocutaneous stimulation of a hand during SWS is shown: 1st night—adaptation, 2nd night—control, 3d and 4th nights—with stimulation during SWA stages of a SWS. Stimulation caused significant increase in average duration of SWS and EEG SWA power (in 11 of 16 subjects), and also well-being and mood improvement in subjects with lowered emotional tone. It is supposed that the received result is caused by functioning of a hypothetical mechanism directed on maintenance and deepening of SWS and counteracting activating, awakening influences of the afferent stimulation. The results can be of value both for understanding the physiological mechanisms of sleep homeostasis and for development of non-pharmacological therapy of sleep disorders.     

The Inhibition of the Dorsal Paragigantocellular Reticular Nucleus Induces Waking and the Activation of All Adrenergic and Noradrenergic Neurons: A Combined Pharmacological and Functional Neuroanatomical Study

GABAergic neurons specifically active during paradoxical sleep (PS) localized in the dorsal paragigantocellular reticular nucleus (DPGi) are known to be responsible for the cessation of activity of the noradrenergic neurons of the locus coeruleus during PS. In the present study, we therefore sought to determine the role of the DPGi in PS onset and maintenance and in the inhibition of the LC noradrenergic neurons during this state. The effect of the inactivation of DPGi neurons on the sleep-waking cycle was examined in rats by microinjection of muscimol, a GABA_A agonist, or clonidine, an alpha-2 adrenergic receptor agonist. Combining immunostaining of the different populations of wake-inducing neurons with that of c-FOS, we then determined whether muscimol inhibition of the DPGi specifically induces the activation of the noradrenergic neurons of the LC. Slow wave sleep and PS were abolished during 3 and 5 h after muscimol injection in the DPGi, respectively. The application of clonidine in the DPGi specifically induced a significant decrease in PS quantities and delayed PS appearance compared to NaCl. We further surprisingly found out that more than 75% of the noradrenergic and adrenergic neurons of all adrenergic and noradrenergic cell groups are activated after muscimol treatment in contrast to the other wake active systems significantly less activated. These results suggest that, in addition to its already know inhibition of LC noradrenergic neurons during PS, the DPGi might inhibit the activity of noradrenergic and adrenergic neurons from all groups during PS, but also to a minor extent during SWS and waking.     

Sleep duration is reduced in elite athletes following night-time competition

ABSTRACT

This study examined the impact of competition on the sleep/wake behaviour of elite athletes. The sleep/wake behaviour of Australian Rules Football players was assessed with wrist activity monitors on the night immediately before, and the night immediately after, a day game and an evening game. The time of day that a game occurred had a marked influence on sleep/wake behaviour later that night. After the evening game, sleep onset was later, time in bed was shorter and total sleep obtained was less than after the day game. It is yet to be determined whether a reduction in sleep after evening games impairs recovery.