Shortening of the photoperiod affects sleep distribution, EEG and cortical temperature in the Djungarian hamster

To asses the influence of photoperiod on sleep regulation EEG, EMG, and cortical temperature were continuously recorded for two baseline days and after 4 h sleep deprivation in Djungarian hamsters (Phodopus sungorus) adapted to a short photoperiod (light dark 816). Comparison to previous data collected in a long photoperiod (lightdark 168) showed several major effects of photoperiod: 1. A prominent change in the 24-h distribution, duration and number of vigilance state episodes, whereas the total amount of sleep and waking was unchanged; 2. Cortical temperature was 0.7°C lower in the short photoperiod; 3. There was a significant negative correlation between cortical temperature and the frequency of REM sleep episodes; and 4. Absolute EEG power density showed a marked reduction in the short photoperiod. After sleep deprivation EEG slow-wave activity (mean power density 0.75–4.0 Hz) in NREM sleep showed a remarkably similar increase in both photoperiods demonstrating the robustness of the homeostatic regulation of sleep. Cortical temperature remained above baseline values after sleep deprivation in the short photoperiod whereas a negative rebound was present in the long photoperiod. Our results support the hypothesis that cortical temperature has a strong influence on REM sleep propensity and indicate the possibility of an optimum cortical temperature for recovery sleep after sleep deprivation. The lower EEG power density in the short photoperiod may contribute to energy conservation.Abbreviations LP long photoperiod - NREM non-rapid-eye-movement - REM rapid-eye-movement - SCN suprachiasmatic nucleus - SD sleep deprivation - SP short photoperiod - SWA slow-wave activity - T _CRT cortical temperature     

非线性动力学在脑电信号分析中的应用

EEG是由大脑产生的非线性时间序列,体现出混沌行为。近年来迅速发展的非线性动力学理论为脑电信号分析开创了一个新的领域。本文综述了近年来非线性动力学在脑电信号研究中（睡眠阶段,麻醉深度,认知过程,精神分裂,痴呆及癫痫）的进展,以期对脑神经动力学有更好的理解。     

不同生理状态时脑电时间序列的三神复杂度计算比较

为了研究不同生理状态下的脑电复杂度变化特点,本文依照１９９４年徐京等人应用的算法,对４种状态（安静睁眼,清醒闭目,浅度睡眠,深度睡眠）下的三种脑电复杂度（Ｋｃ,Ｃ１,Ｃ２）的变化规律进行了比较分析,Ｋｃ与Ｃ１的变化相一致,从安静睁眼剂的清醒闭目到浅睡到深度睡眠,Ｋｃ与Ｃ１值均依次下降,Ｃ２值的变化则与它们相反,尤其在深睡期显著升高,实验结果提示,复杂度可做为脑电时间序列的研究指标。     

不同生理状态时脑电时间序列的三神复杂度计算比较

为了研究不同生理状态下的脑电复杂度变化特点,本文依照１９９４年徐京华等人应用的算法,对４种状态（安静睁眼、清醒闭目、浅度睡眠、深度睡眠）下的三种脑电复杂度（ＫＣ、Ｃ１、２）的变化规律进行了比较分析,ＫＣ与Ｃ１的变化相一致。从安静睁眼到清醒闭目到浅睡到深度睡眠,ＫＣ与Ｃ１值均依次下降。Ｃ２值的变化则与它们相反,尤其在深睡期显著升高。实验结果提示,复杂度可做为脑电时间序列的研究指标。     

健康早产儿24小时脑电图的定量评价

早产儿的生物学行为主要以睡眠为主,因此了解各个睡眠阶段的脑电图模型,对临床客观评价早产儿的大脑发育特点及健康状况具有重要的临床意义。本文旨在探讨健康早产儿不同睡眠阶段脑电图特点,进而为其睡眠阶段的自动判定提供标准。应用多导生理记录仪对24例健康早产儿进行了41次Fp1-C3双电极连续24小时脑电图记录,同时用两台摄像机同步记录眼球运动及肢体运动。依据呼吸、眼球及肢体运动视觉判定睡眠阶段。应用自回两台摄像机同步记录眼球运动最适赤池信息量准则（Min-AIC)、总功率（TP）、δ功率（δP）、θ功率（θP）、α功率（αP）、β功率（βP）及不连续性（Dis）进行分析。结果显示Min-AIC,TP,δP及Dis四个变量依睡眠阶段不同有显著性差异（P＜0．01）。多变量判别分析亦显示联合这四个变量可对睡眠阶段进行判定。联合Min-AIC、TP、δP及Dis四个变量适于对胎龄大于30周的健康早产儿的睡眠阶段进行判定。     

视频脑电图鉴别诊断癫痫患者睡眠障碍、认知障碍的临床价值研究

目的:探讨视频脑电图诊断癫痫患者睡眠障碍、认知障碍的临床价值。方法:选取2014年1月~2016年12月在我院神经内科进行诊治的癫痫患者236例作为癫痫组,另选取同期的健康患者家属或者其他健康体检者236例作为正常对照组,对两组进行视频脑电图联合睡眠参数分析;并对癫痫组视频脑电图联合认知参数进行分析。结果:癫痫组睡眠Ⅰ~Ⅱ期时间显著长于正常对照组且具有统计学差异(P=0.000),睡眠Ⅲ~Ⅳ期时间显著短于正常对照组且具有统计学差异(P=0.000),睡眠时相转换频率、觉醒指数均显著高于正常对照组且均具有统计学差异(P=0.000);清醒期、睡眠期不同痫样放电指数(IED)的WAIS-RC IQ和WMS-RC MQ均具有统计学差异(P0.05),10%IED≤50%者的WAIS-RC IQ和WMS-RC MQ均显著低于1%IED≤10%者且均具有统计学差异(P0.05),IED 10%可能是痫样放电影响患者认知功能的最低阈值。结论:视频脑电图在癫痫患者睡眠障碍、认知障碍识别中具有重要的临床价值。     

EEG in Children: Periodometric Analysis,Typology, and Age Peculiarities

We carried out a computer analysis of the EEG of 169 healthy schoolchildren (6 to 17 years old) with the use of a periodometric approach allowing us to obtain a number of quantitative indices that characterize the temporal structure of the analyzed EEG segment (histogram of distribution of the frequencies of EEG oscillations within the analyzed time period, indices of the different rhythms, and matrix of the probabilities of conversion from waves of one frequency range to waves of other ranges). We demonstrated that data of the periodometric analysis can be used for objective classification of EEG patterns. In children of different age groups, five types of background EEG activity were classified and described; we also demonstrated that the intragroup frequencies of these EEG types vary in healthy children with age. We discuss the advantages and disadvantages of the periodometric analysis of EEG, as well as the prospects and expediency of use of this analysis in physiological studies and in clinics.     

脑电监测SD大鼠异氟醚全身麻醉模型的建立及脑电分析

目的:建立脑电监测SD大鼠异氟醚全身麻醉模型并分析脑电监测结果。方法:随机选取SD大鼠20只,先行脑电电极置入术,术后使用密闭吸入麻醉动物行为学观察圆筒,观察异氟醚引起的麻醉诱导、维持、觉醒状态并记录诱导、觉醒时间。将记录的行为学结果对照典型脑电图波形改变判断麻醉深度。结果:实验SD大鼠均检测出脑电图,通过对照行为学观察发现动态脑电监测结果同异氟醚麻醉过程进展一致。在麻醉过程中SD大鼠出现典型的全身麻醉脑电循环。结论:动态脑电监测和SD大鼠行为学观察可以准确反应全身麻醉深度。     

Effects of the anesthetic agent propofol on neural populations

The neuronal mechanisms of general anesthesia are still poorly understood. Besides several characteristic features of anesthesia observed in experiments, a prominent effect is the bi-phasic change of power in the observed electroencephalogram (EEG), i.e. the initial increase and subsequent decrease of the EEG-power in several frequency bands while increasing the concentration of the anaesthetic agent. The present work aims to derive analytical conditions for this bi-phasic spectral behavior by the study of a neural population model. This model describes mathematically the effective membrane potential and involves excitatory and inhibitory synapses, excitatory and inhibitory cells, nonlocal spatial interactions and a finite axonal conduction speed. The work derives conditions for synaptic time constants based on experimental results and gives conditions on the resting state stability. Further the power spectrum of Local Field Potentials and EEG generated by the neural activity is derived analytically and allow for the detailed study of bi-spectral power changes. We find bi-phasic power changes both in monostable and bistable system regime, affirming the omnipresence of bi-spectral power changes in anesthesia. Further the work gives conditions for the strong increase of power in the δ-frequency band for large propofol concentrations as observed in experiments.     

树鼩24小时昼夜节律的探讨

自从Carlsson(1922)时期到现在,树鲍(tupaiidae)的分类地位问题一直引起人们很大的兴趣和讨论。历史上树鼩曾不止一次地被错定为松鼠(Grzimek 1975)。虽然人们对树鼩是否属食虫目(Insectivora),原猿亚目(Prosimiae)或另立新目方面尚存在不少争议,但大多数人都同意灵长类在大约第三纪自食虫目演化而来,而树鼩是目前地球上幸存的少数几种灵长类原宗(Ptimitive stock)中的一种(chiarelli 1974;Lende 1970;Grzimak1975;Casseday等1979)。 树鼩可分成2亚科,6属,47种和约100个亚种,它们绝大部分产自亚洲南部。本研     

模拟高海拔低氧对人体睡眠的影响

在模拟不同海拔高度的低氧条件暴露下,我们记录和测定了6名对象的睡眠生理各项指标。结果如下:在急性低氧暴露下所有对象均出现了睡眠障碍,主要是在夜间规定睡眠时间中觉醒期和觉醒次数增加,深睡眠期和快眼动期减少,睡眠各期的呼吸频率和心率增加。随着低氧暴露时间的延长和多次空气潜水后,各睡眠生理指标有向海平对照值水平发展的趋势。4500m以上的低氧暴露下,所有对象在睡眠中都有周期性呼吸现象出现,并影响体内的缺氧。     

Automatic EEG arousal detection for sleep apnea syndrome

Electroencephalographic (EEG) arousals are seen in EEG recordings as an awakening response of the human brain. Sleep apnea is a serious sleep disorder. Severe sleep apnea brings about EEG arousals and sleep for patients with sleep apnea syndrome (SAS) is thus frequently interrupted. The number of respiratory-related arousals during the whole night on PSG recordings is directly related to the quality of sleep. Detecting EEG arousals in the PSG record is thus a significant task for clinical diagnosis in sleep medicine. In this paper, a method for automatic detection of EEG arousals in SAS patients was proposed. To effectively detect respiratory-related arousals, threshold values were determined according to pathological events as sleep apnea and electromyogram (EMG). If resumption of ventilation (end of the apnea interval) was detected, much lower thresholds were adopted for detecting EEG arousals, including relatively doubtful arousals. Conversely, threshold was maintained high when pathological events were undetected. The proposed method was applied to polysomnographic (PSG) records of eight patients with SAS and accuracy of EEG arousal detection was verified by comparative visual inspection. Effectiveness of the proposed method in clinical diagnosis was also investigated.     

Train drivers' sleep quality and quantity during extended relay operations

Relay operations are an important mode of freight transportation within Australia. Relay work requires multiple crews to drive the train continuously from one specified destination to another and return. Importantly, the nature of relay work requires train drivers to sleep on-board during designated resting shifts. The main aim of the present study was to investigate the quality and quantity of sleep obtained in on-board rest facilities (relay vans) during extended (four-day) relay operations. Drivers (n=9) working the Port Augusta to Darwin relay operation volunteered to participate. The first leg of the trip typically took 40 h followed by an overnight stay in Darwin (between 8-12 h) prior to return. Two crews, each consisting of two drivers, changed every 8 h, giving the crew an 8 h rest in the relay van prior to each 8 h working shift. Using polysomnography, home sleep data were collected prior to and following each trip using a standard five-channel EEG montage. All sleep periods during the relay trip (including Darwin) were also recorded. Additionally, subjective sleep quality ratings were recorded following each sleep period. Analyses revealed that the quantity of sleep obtained in the relay vans (3.3 h) was significantly reduced compared to home (6.8 h). In general, the total sleep time was increased at night and reduced during the day. In terms of quality, sleep onset latency, sleep efficiency, and amount of slow wave and rapid eye movement sleep did not differ significantly between home and the relay vans. The results of the study highlight sleep quantity as the main concern during extended relay operations. Future research should focus on investigating the subjective and objective impact of this sleep reduction on waking functions.     

Human plasma DSIP decreases at the initiation of sleep at different circadian times

Nocturnal plasma delta sleep-inducing peptide-like immunoreactivity (DSIP-LI) was determined serially in seven healthy male subjects. Time courses during nocturnal sleep (2300-0800 h), nocturnal sleep deprivation (2300-0500 h), and morning recovery sleep (0500–0800 h) after sleep deprivation were compared. A significant decrease in plasma DSIP-LI was found at the transition from wakefulness to sleep in both evening sleep (2300 h) and morning recovery sleep (0500 h). Time courses were accompanied by physiological changes in sleep electroencephalographic slow-wave activity, and in plasma concentrations of cortisol and human growth hormone. No sleep stage specificity was found. It is concluded that DSIP is influenced by the initiation of sleep.     

Quantification of Sleepiness Through Principal Component Analysis of the Electroencephalographic Spectrum

Although circadian and sleep research has made extraordinary progress in the recent years, one remaining challenge is the objective quantification of sleepiness in individuals suffering from sleep deprivation, sleep restriction, and excessive somnolence. The major goal of the present study was to apply principal component analysis to the wake electroencephalographic (EEG) spectrum in order to establish an objective measure of sleepiness. The present analysis was led by the hypothesis that in sleep-deprived individuals, the time course of self-rated sleepiness correlates with the time course score on the 2nd principal component of the EEG spectrum. The resting EEG of 15 young subjects was recorded at 2-h intervals for 32–50?h. Principal component analysis was performed on the sets of 16 single-Hz log-transformed EEG powers (1–16?Hz frequency range). The time course of self-perceived sleepiness correlated strongly with the time course of the 2nd principal component score, irrespective of derivation (frontal or occipital) and of analyzed section of the 7-min EEG record (2-min section with eyes open or any of the five 1-min sections with eyes closed). This result indicates the possibility of deriving an objective index of physiological sleepiness by applying principal component analysis to the wake EEG spectrum. (Author correspondence: putilov@ngs.ru)     

应用生长、分级的SOM模型进行意识任务分类

提出一种使用生长、分级的自组织映射（growing hierarchical self-organizing map,GHSOM）模型进行基于EEG信号的意识任务分类来实现脑机接口技术的方法。GHSOM模型是自组织映射（self-organizing map,SOM）的一种变体,由多层的SOM组成,具有一定的分级结构,能够表达数据中不同层次的信息。同时研究了使用平均量化误差（mean quantization error,mqe）和量化误差（quantization error,qe）两种方法实现的GHSOM模型对意识任务分类的作用。结果表明,GHSOM模型对于意识任务的可分性能够提供可视化的信息,并且发现使用量化误差方法实现的GHSOM模型提供较多的数据信息和较高的分类精度。使用GHSOM模型进行了5类意识任务的分类,平均分类精度可达80％。     

Thermopreference,tolerance and metabolic rate of early stages juvenile Octopus maya acclimated to different temperatures

Thermopreference, tolerance and oxygen consumption rates of early juveniles Octopus maya (O. maya; weight range 0.38–0.78 g) were determined after acclimating the octopuses to temperatures (18, 22, 26, and 30 °C) for 20 days. The results indicated a direct relationship between preferred temperature (PT) and acclimated temperature, the PT was 23.4 °C. Critical Thermal Maxima, (CTMax; 31.8±1.2, 32.7±0.9, 34.8±1.4 and 36.5±1.0) and Critical Thermal Minima, (CTMin; 11.6±0.2, 12.8±0.6, 13.7±1.0, 19.00±0.9) increased significantly (P<0.05) with increasing acclimation temperatures. The endpoint for CTMax was ink release and for CTMin was tentacles curled, respectively. A thermal tolerance polygon over the range of 18–30 °C resulted in a calculated area of 210.0 °C². The oxygen consumption rate increased significantly α=0.05 with increasing acclimation temperatures between 18 and 30 °C. Maximum and minimum temperature quotients (Q₁₀) were observed between 26–30 °C and 22–26 °C as 3.03 and 1.71, respectively. These results suggest that O. maya has an increased capability for adapting to moderate temperatures, and suggest increased culture potential in subtropical regions southeast of México.     

脑电监测SD大鼠异氟醚全身麻醉模型的建立及脑电分析

目的建立脑电监测SD大鼠异氟醚全身麻醉模型并分析脑电监测结果。方法：随机选取SD大鼠20只,先行脑电电极置入术,术后使用密闭吸入麻醉动物行为学观察圆筒,观察异氟醚引起的麻醉诱导、维持、觉醒状态并记录诱导、觉醒时间。将记录的行为学结果对照典型脑电图波形改变判断麻醉深度。结果：实验SD大鼠均检测出脑电图,通过对照行为学观察发现动态脑电监、}测结果同异氟醚麻醉过程进展一致。在麻醉过程中SD大鼠出现典型的全身麻醉脑电循环。结论：动态脑电监测和SD大鼠行为学观察可以准确反应全身麻醉深度。     

Young Women With Major Depression Live on Higher Homeostatic Sleep Pressure Than Healthy Controls

There is mounting evidence for the involvement of the sleep-wake cycle and the circadian system in the pathogenesis of major depression. However, only a few studies so far focused on sleep and circadian rhythms under controlled experimental conditions. Thus, it remains unclear whether homeostatic sleep pressure or circadian rhythms, or both, are altered in depression. Here, the authors aimed at quantifying homeostatic and circadian sleep-wake regulatory mechanisms in young women suffering from major depressive disorder and healthy controls during a multiple nap paradigm under constant routine conditions. After an 8-h baseline night, 9 depressed women, 8 healthy young women, and 8 healthy older women underwent a 40-h multiple nap protocol (10 short sleep-wake cycles) followed by an 8-h recovery night. Polysomnographic recordings were done continuously, and subjective sleepiness was assessed. In order to measure circadian output, salivary melatonin samples were collected during scheduled wakefulness, and the circadian modulation of sleep spindles was analyzed with reference to the timing of melatonin secretion. Sleep parameters as well as non-rapid eye movement (NREM) sleep electroencephalographic (EEG) spectra were determined for collapsed left, central, and right frontal, central, parietal, and occipital derivations for the night and nap-sleep episodes in the frequency range .75–25?Hz. Young depressed women showed higher frontal EEG delta activity, as a marker of homeostatic sleep pressure, compared to healthy young and older women across both night sleep episodes together with significantly higher subjective sleepiness. Higher delta sleep EEG activity in the naps during the biological day were observed in young depressed women along with reduced nighttime melatonin secretion as compared to healthy young volunteers. The circadian modulation of sleep spindles between the biological night and day was virtually absent in healthy older women and partially impaired in young depressed women. These data provide strong evidence for higher homeostatic sleep pressure in young moderately depressed women, along with some indications for impairment of the strength of the endogenous circadian output signal involved in sleep-wake regulation. This finding may have important repercussions on the treatment of the illness as such that a selective suppression of EEG slow-wave activity could promote acute mood improvement. (Author correspondence: Christian.cajochen@upkbs.ch)