Longitudinal Study of Infant Sleep: Results of 14 Subjects Studied at Monthly Intervals

The sleep of 14 normal infants was studied every month throughout the first year. A computer program incorporated an analysis of multiple variables from polygraphic data as recommended by a recently standardized new born scoring manual. Under our recording conditions, quiet sleep increased during the first 3 months but indeterminate sleep did not decline over the year as expected. This finding is incompatible with the notion that indeterminate sleep reflects immaturity or “undifferentiation” in sleep organization.     

睡眠剥夺对HSP70表达及脑超微结构的影响

目的：观察睡眠剥夺（SD）后大鼠脑组织HSP70表达的变化及对超微结构的影响。方法：44只雄性SD大鼠随机分为11组，每组4只，免疫组织化学方法检测HSP70的表达，电镜观察海马超微结构的变化。结果：睡眠剥夺后12小时即可在大脑皮质及海马观察到HSP70阳性细胞，2—3天数量达到高峰，7天时明显下降。白天睡眠剥夺12小时（SDd12h）组HSP70阳性细胞数较夜晚睡眠剥夺12小时（SDn12h）组多（P〈0．05）。RS组大脑皮质HSP70阳性细胞数较白天睡眠剥夺1天（SDd1d）组减少（P〈0．05）。白天睡眠剥夺3天（SDd3d）海马出现超微结构改变，白天睡眠剥夺7天（SDd7d）后改变更加明显。结论：睡眠剥夺可影响大鼠脑组织HSP70表达及超微结构。     

Sleep on the Night Shift: 24-Hour EEG Monitoring of Spontaneous Sleep/Wake Behavior

The present study sought to objectively describe the spontaneous sleep/wakefulness pattern of shift workers during a 24-hour period. Portable Medilog tape-recorders were used for ambulatory EEG monitoring of 25 male papermill workers (25-55 years) during days with night and afternoon work. The results showed that sleep after night work was two hours shorter than after afternoon work. The sleep reduction affected mainly Stage 2 and REM sleep while slow wave sleep was unchanged. In connection with night work 28% of the workers took a nap in the afternoon. These naps contained a large proportion of slow wave sleep and were, apparently, caused by the sleep deficit after the short main sleep period. The EEG recordings also revealed that 20% of the participants had sleep episodes during night work. These naps were as long as the afternoon naps, were experienced as "dozing offs" rather than naps, occurred at the time of the trough of the circadian wakefulness rhythm, and were concomitant with extreme subjective sleepiness and low rated work load. It was concluded that not only the sleep of shift workers was disturbed, but also the wakefulness--to the extent that sleepiness during night work sometimes reached a level where reasonable wakefulness could not be maintained. The latter observation is probably of special importance in work situations demanding a great responsibility for human lives or for great economic values.     

EEG delta power during sleep in young and old rats

Delta EEG power density, which has been viewed as a measure of intensity of NREM sleep, declines across the lifetime in humans, cats, and hamsters, but data in rats have been unclear. It is also uncertain whether older rats differ from younger animals in the degree of change in delta power during recovery sleep following short-term sleep deprivation. We have examined delta power density in NREM sleep under baseline conditions and following 48 h of sleep deprivation in young (3 months), middle-aged (12 months), and older (24 months) rats. The presence or absence of age effects was highly dependent on the method of normalizing the data. When expressed as a fraction of total NREM EEG power, there was no age effect on baseline delta power density, or on the change from baseline to recovery conditions. When expressed as a multiple of delta power in REM under the same condition, the younger rats had higher delta power density than the middle-aged and older rats. For all the ages combined, there was an increase in delta power density in the recovery condition. When examined by age, the younger rats (which started from a higher level of delta power density than the other groups) did not have an increase in delta during recovery; the middle-aged rats tended to, and the older rats (which started from lower baseline levels) significantly increased delta power density in the recovery condition. This suggests that the lower delta power seen during baseline in older rats is not due to decreased ability to generate delta activity.     

Periodic breathing and genetics

The episodic waxing and waning of ventilation is a fundamental event in sleep apnea syndromes. Post-hypoxic frequency decline (PHFD) and periodic breathing (PB) are evoked by brief hypoxic exposures in unanaesthetized and unrestrained inbred C57BL/6J mice, but not in A/J mice; and expression of PHFD differs not only among these mice strains but in among rat strains as well. These observations along with the current literature on genetic factors that operate on ventilatory behavior at rest and with chemosensory drive lead to the hypothesis that genetic factors infer some proportion of risk for the ventilatory instability observed in human sleep apnea syndromes.     

网络成瘾和睡眠时长在青少年受校园欺凌与抑郁间的链式中介作用

目的 探索青少年网络成瘾和睡眠时长在受校园欺凌与抑郁关系之间的中介作用,为青少年抑郁的预防干预提供依据。 方法 使用青少年健康相关危险行为问卷及CES - D抑郁量表,采用多阶段整群抽样法抽取徐州市4 190名青少年进行问卷调查。结果 在控制人口学等变量后,受校园欺凌、网络成瘾、睡眠时长对抑郁均有预测作用（r = 0.283,P＜0.01;r = 0.331,P＜0.01;r = - 0.184,P＜0.01）。路径分析表明,网络成瘾在受校园欺凌和青少年抑郁之间起中介作用;网络成瘾和睡眠时长在受校园欺凌和青少年抑郁间起链式中介作用。结论 受校园欺凌不仅直接影响青少年抑郁,还通过网络成瘾和睡眠时长的链式中介作用间接影响青少年抑郁。可通过减少青少年网络使用和提高睡眠时长来降低受校园欺凌对青少年抑郁的影响。     

Sleep following intense physical exercise stabilizes motor learning in typically developing boys

There is compelling evidence that sleep (N2, REM sleep, but also N3) supports the consolidation of motor memory in adults. Although children express higher levels of REM sleep and N3, it is still not understood why sleep does not benefit the consolidation of motor memory in children as in adults. Here, we aimed to manipulate sleep by daytime physical exercise in typically developing boys (N = 12; range 9–12 yrs) to test the impact on sleep and motor learning. The manipulation consisted of 1 h of intense ergometer exercise during the daytime before a night of restorative sleep. In a rest control condition, children were seated comfortably and listened to an audio drama. Motor learning was assessed with a visuomotor finger sequence tapping task; in both conditions learning took place before either exercise or rest. Prior to sleep in the sleep laboratory, motor memory was assessed as a baseline. Motor memory was again collected in the morning after a night of sleep in the lab. While there was no change in N3, we found prolonged REM sleep latency after physical activity compared to rest, corresponding to a prolonged first sleep cycle. With respect to motor learning, we found superior accuracy of motor performance after physical exercise compared to rest. Our findings suggest that physical exercise during the daytime stabilizes sleep-dependent motor learning.     

Sleep Problems among Mothers of Youth Stopped by the Police

Police stops are the most common form of criminal justice exposure in the USA, and are particularly common among urban youth, with 23% of them reporting a stop by the age of 15. While recent work has begun to illuminate the health impacts of police stops for these youth, little is known about the health consequences of youth police contact for the mothers of youth stopped by the police. The current study employs data from the Fragile Families and Child Wellbeing Study (FFCWS), a sample of urban, at-risk youth and their families. Multivariate logistic regression models are conducted to examine the link between youth police stops and sleep difficulties among mothers. Additional analyses examine whether the features and consequences of police stops are associated with sleep difficulties among mothers. The findings indicate that mothers with youth who have experienced police stops are more than twice as likely to report both depression- and anxiety-related sleep difficulties compared to their counterparts. Furthermore, stops with certain features—including those characterized by intrusiveness, high trauma, and high stigma—emerged as consistently significant predictors of maternal sleep difficulties. The findings suggest that mothers who are vicariously exposed to police contact via their children are a vulnerable group. Given the non-random distribution of police contact across the population of youth, with police contact concentrated among children of color, the findings suggest that police contact may exacerbate racial inequalities in sleep, which may itself contribute to racial disparities in broader mental and physical health outcomes.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11524-021-00518-1.     

Metabolic rate and substrate oxidation of young males with obesity at the different sleep stages

ObjectiveInsufficient and poor-quality sleep among young adults is closely related to obesity and may impact metabolic processes. The mobilization and use of endogenous substrates during sleep, especially fat oxidation, is essential for energy metabolism. This study investigated whether there are differences in sleep structure, metabolic rate, substrate oxidation, and the respiratory quotient (RQ) between young males with normal weight and obesity according to sleep stages and overnight sleep.MethodsFifteen young males with normal weight and fifteen with obesity posited electrodes of polysomnography (PSG) and slept in the metabolic chamber for estimation of sleep structure, sleep metabolic rate (SMR), carbohydrate oxidation (CHOO), fat oxidation (FATO), and RQ. Fat-free mass (FFM) was measured by bioelectrical impedance analysis.ResultsThe sleep period time (p = 0.038) and total sleep time (p = 0.032) were significantly shorter in the obesity group than in the normal-weight group. The obesity group also had a longer sleep latency (p = 0.034) and more sleep-turning events (p = 0.018). CHOO/FFM and the RQ were higher in the obesity group while FATO/FFM was significantly higher in the normal-weight group. FATO/FFM was also higher in the normal-weight group in each sleep stage whereas the RQ was higher in the obesity group (p < 0.05).ConclusionsYoung males with obesity showed lower fat oxidation and more dominant carbohydrate-derived fuel oxidation than normal-weight during sleep and experienced shorter sleep periods and total sleep time.