scholarly journals Urethane Anesthesia Exhibits Neurophysiological Correlates of Unconsciousness and is Distinct from Sleep

2021 ◽  
Author(s):  
Alejandra Mondino ◽  
Joaquin Gonzalez ◽  
Duan Li ◽  
Diego M. Mateos ◽  
Lucia Osorio ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Nrem Sleep ◽  
Loss Of Consciousness ◽  
General Anesthetic ◽  
Wave State ◽  
Natural Sleep ◽  
Urethane Anesthesia ◽  
Activated State ◽  
The Relationship ◽  
Physiological Sleep

Urethane is a general anesthetic widely used in animal research. It is unique among anesthetics because urethane anesthesia alternates between macroscopically distinct electrographic states: a slow-wave state that resembles NREM sleep (NREMure), and an activated state with features of both REM sleep and wakefulness (REMure). However, the relationship between urethane anesthesia and physiological sleep is still unclear. In this study, electroencephalography (EEG) and electromyography were recorded in chronically prepared rats during natural sleep-wake states and during urethane anesthesia. We subsequently analyzed the EEG signatures associated with the loss of consciousness and found that, in comparison to natural sleep-wake states, the power, coherence, directed connectivity and complexity of brain oscillations are distinct during urethane. We also demonstrate that both urethane states have clear EEG signatures of general anesthesia. Thus, despite superficial similarities that have led others to conclude that urethane is a model of sleep, the electrocortical traits of depressed and activated states during urethane anesthesia differ from physiological sleep states.

scholarly journals The relationship between fasting-induced torpor, sleep and waking in laboratory mice

SLEEP ◽  
2021 ◽  
Author(s):  
Yi-Ge Huang ◽  
Sarah J Flaherty ◽  
Carina A Pothecary ◽  
Russell G Foster ◽  
Stuart N Peirson ◽  
...  
Keyword(s):  
Body Temperature ◽  
Rem Sleep ◽  
Brain Activity ◽  
Mammalian Species ◽  
Nrem Sleep ◽  
Laboratory Mice ◽  
State Classification ◽  
Metabolic Suppression ◽  
The Relationship ◽  
Electroencephalogram Eeg

Abstract Study objectives Torpor is a regulated and reversible state of metabolic suppression used by many mammalian species to conserve energy. Whereas the relationship between torpor and sleep has been well-studied in seasonal hibernators, less is known about the effects of fasting-induced torpor on states of vigilance and brain activity in laboratory mice. Methods Continuous monitoring of electroencephalogram (EEG), electromyogram (EMG) and surface body temperature was undertaken in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. Results All animals showed bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of NREM sleep, REM sleep and wakefulness enabled us to perform vigilance-state classification in all cases. Consistent with previous studies, hypothermic bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing surface body temperature. During deep hypothermia, REM sleep was largely abolished, and we observed shivering-associated intense bursts of muscle activity. Conclusions Our study highlights important similarities between EEG signatures of fasting-induced torpor in mice, daily torpor in Djungarian hamsters and hibernation in seasonally-hibernating species. Future studies are necessary to clarify the effects on fasting-induced torpor on subsequent sleep.

Correlations using the NREM-REM sleep cycle frequency support distinct regulation mechanisms for REM and NREM sleep

2002 ◽  
Vol 93 (1) ◽  
pp. 141-146 ◽  
Author(s):  
O. Le Bon ◽  
L. Staner ◽  
S. K. Rivelli ◽  
G. Hoffmann ◽  
I. Pelc ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Healthy Subjects ◽  
Nrem Sleep ◽  
Sleep Cycle ◽  
Cycle Frequency ◽  
Regulation Mechanisms ◽  
The Mean ◽  
Number Of Cycles ◽  
The Relationship ◽  
Sleep Cycles

Polysomnograms of most homeothermic species distinguish two states, rapid eye movement (REM) and non-REM (NREM) sleep. These alternate several times during the night for reasons and following rules that remain poorly understood. It is unknown whether each state has its own function and regulation or whether they represent two facets of the same process. The present study compared the mean REM/NREM sleep ratio and the mean number of NREM-REM sleep cycles across 3 consecutive nights. The rationale was that, if REM and NREM sleep are tightly associated, their ratio should be comparable whatever the cycle frequency in the night. Twenty-six healthy subjects of both sexes were recorded at their home for 4 consecutive nights. The correlation between the REM/NREM sleep ratio and the number of cycles was highly significant. Of the two sleep components, REM sleep was associated to the number of cycles, whereas NREM sleep was not. This suggests that the relationship between REM sleep and NREM sleep is rather weak within cycles, does not support the concept of NREM-REM sleep cycles as miniature units of the sleep process, and favors the concept of distinct mechanisms of regulation for the two components.

scholarly journals The relationship between fasting-induced torpor, sleep and wakefulness in the laboratory mouse

2020 ◽  
Author(s):  
Yi G. Huang ◽  
Sarah J. Flaherty ◽  
Carina A. Pothecary ◽  
Russell G. Foster ◽  
Stuart N. Peirson ◽  
...  
Keyword(s):  
Body Temperature ◽  
Rem Sleep ◽  
Brain Activity ◽  
Mammalian Species ◽  
Laboratory Mouse ◽  
Nrem Sleep ◽  
Early Ontogeny ◽  
State Classification ◽  
The Relationship ◽  
Electroencephalogram Eeg

AbstractTorpor is a regulated reversible state of metabolic suppression used by many mammalian species to conserve energy. Although torpor has been studied extensively in terms of general physiology, metabolism and neuroendocrinology, the effects of hypometabolism and associated hypothermia on brain activity and states of vigilance have received little attention. Here we performed continuous monitoring of electroencephalogram (EEG), electromyogram (EMG) and peripheral body temperature in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. All animals showed prominent bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of NREM sleep, REM sleep and wakefulness allowed us to perform vigilance-state classification in all cases. Invariably, hypothermia bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing body temperature. Furthermore, during deep hypothermia REM sleep was largely abolished, but we observed brief and intense bursts of muscle activity, which resembled the regular motor discharges seen during early ontogeny associated with immature sleep patterns. We conclude that torpor and sleep are electrophysiologically on a continuum, and that, in order for torpor to occur, mice need to first transition through euthermic sleep.

Effects of selective sleep deprivation on ventilation during recovery sleep in normal humans

1992 ◽  
Vol 72 (1) ◽  
pp. 100-109 ◽  
Author(s):  
J. B. Neilly ◽  
N. B. Kribbs ◽  
G. Maislin ◽  
A. I. Pack
Keyword(s):  
Sleep Deprivation ◽  
Eye Movement ◽  
Rem Sleep ◽  
Minute Ventilation ◽  
Nrem Sleep ◽  
Rapid Eye Movement ◽  
Rem Sleep Deprivation ◽  
Sleep Period ◽  
Recovery Sleep ◽  
The Relationship

To assess the effects of selective sleep loss on ventilation during recovery sleep, we deprived 10 healthy young adult humans of rapid-eye-movement (REM) sleep for 48 h and compared ventilation measured during the recovery night with that measured during the baseline night. At a later date we repeated the study using awakenings during non-rapid-eye-movement (NREM) sleep at the same frequency as in REM sleep deprivation. Neither intervention produced significant changes in average minute ventilation during presleep wakefulness, NREM sleep, or the first REM sleep period. By contrast, both interventions resulted in an increased frequency of breaths, in which ventilation was reduced below the range for tonic REM sleep, and in an increased number of longer episodes, in which ventilation was reduced during the first REM sleep period on the recovery night. The changes after REM sleep deprivation were largely due to an increase in the duration of the REM sleep period with an increase in the total phasic activity and, to a lesser extent, to changes in the relationship between ventilatory components and phasic eye movements. The changes in ventilation after partial NREM sleep deprivation were associated with more pronounced changes in the relationship between specific ventilatory components and eye movement density, whereas no change was observed in the composition of the first REM sleep period. These findings demonstrate that sleep deprivation leads to changes in ventilation during subsequent REM sleep.

scholarly journals Optogenetic activation of cholinergic neurons in the PPT or LDT induces REM sleep

2014 ◽  
Vol 112 (2) ◽  
pp. 584-589 ◽  
Author(s):  
Christa J. Van Dort ◽  
Daniel P. Zachs ◽  
Jonathan D. Kenny ◽  
Shu Zheng ◽  
Rebecca R. Goldblum ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Cholinergic Neurons ◽  
Nrem Sleep ◽  
Sleep Regulation ◽  
Natural Sleep ◽  
Sleep Episode ◽  
Episode Duration ◽  
Laterodorsal Tegmentum ◽  
Mesopontine Tegmentum

Rapid eye movement (REM) sleep is an important component of the natural sleep/wake cycle, yet the mechanisms that regulate REM sleep remain incompletely understood. Cholinergic neurons in the mesopontine tegmentum have been implicated in REM sleep regulation, but lesions of this area have had varying effects on REM sleep. Therefore, this study aimed to clarify the role of cholinergic neurons in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT) in REM sleep generation. Selective optogenetic activation of cholinergic neurons in the PPT or LDT during non-REM (NREM) sleep increased the number of REM sleep episodes and did not change REM sleep episode duration. Activation of cholinergic neurons in the PPT or LDT during NREM sleep was sufficient to induce REM sleep.

scholarly journals The effect of dream report collection and dream incorporation on memory consolidation during sleep

2018 ◽  
Author(s):  
Sarah F. Schoch ◽  
Maren J. Cordi ◽  
Michael Schredl ◽  
Bjöern Rasch
Keyword(s):  
Task Performance ◽  
Rem Sleep ◽  
Memory Consolidation ◽  
Memory Performance ◽  
Nrem Sleep ◽  
Learning Task ◽  
Association Learning ◽  
Dream Report ◽  
Waking Up ◽  
The Relationship

AbstractWaking up during the night to collect dream reports is a commonly used method to study dreams. This method has also been applied in studies on the relationship between dreams and memory consolidation. However, it is unclear if these awakenings influence ongoing memory consolidation processes. Furthermore, only few studies have examined if task incorporation into dreams is related to enhanced performance in the task. Here we compare memory performance in a word-picture association learning task after a night with (up to six awakenings) and without awakenings in 22 young and healthy participants. We then examine if the task is successfully incorporated into the dreams and if this incorporation is related to the task performance the next morning. We show that while the awakenings impair both subjective and objective sleep quality, these awakenings did not impair ongoing memory consolidation during sleep. When dreams were collected during the night by awakenings, memories of the learning task were successfully incorporated into dreams. No incorporation occurred in dreams collected only in the morning. Task incorporation into NREM sleep dreams, but not REM sleep dreams showed a relationship with task performance the next morning.We conclude that the method of awakenings to collect dream reports is suitable for dream and memory studies, and is even crucial to uncover task incorporations. Furthermore, our study suggests that dreams in NREM rather than REM sleep might be related to processes of memory consolidation during sleep.

Benzodiazepines and Sleep Architecture: a Systematic Review.

2021 ◽  
Vol 20 ◽  
Author(s):  
Felipe Maraucci Ribeiro de Mendonça ◽  
Giulia Paulo Rossi Ribeiro de Mendonça ◽  
Laura Costa Souza ◽  
Lucas Pequeno Galvão ◽  
Henrique Soares Paiva ◽  
...  
Keyword(s):  
Systematic Review ◽  
Eye Movement ◽  
Rem Sleep ◽  
Nrem Sleep ◽  
Sleep Architecture ◽  
Professional Judgment ◽  
Rapid Eye Movement ◽  
Two Phases ◽  
Physiological Sleep

Background: Insomnia, defined as a difficulty in initiating or maintaining sleep, is a relevant medical issue. Benzodiazepines (BZDs) are commonly prescribed to treat insomnia. Two phases characterize human sleep structure: sleep with Non-Rapid Eye Movement (NREM) and sleep with Rapid Eye Movement (REM). Physiological sleep includes NREM and REM phases in a continuous cycle known as “Sleep Architecture.” Objective: This systematic review summarizes the studies that investigated BZDs changes on Sleep Architecture. Methods: The article’s selection included human clinical trials (in English, Portuguese, or Spanish) only, specifically focused on BZDs effects on sleep architecture. PubMed, BVS, and GoogleScholar databases were searched. Results: Findings on BZDs effects on sleep architecture confirm an increase in stage 2 of NREM sleep and a decrease in time of stages 3 and 4 of NREM sleep with a reduction in time of REM sleep during the nocturnal sleep. Conclusion: Variations in NREM and REM sleep may lead to deficits in concentration and working memory, and weight gain. The increase in stage 2 of NREM sleep may lead to a subjective improvement of sleep quality with no awakenings. BZDz should be prescribed with zeal and professional judgment. These patients should be closely monitored for possible long-term side effects.

scholarly journals Diaphragm long-term facilitation following acute intermittent hypoxia during wakefulness and sleep

2011 ◽  
Vol 110 (5) ◽  
pp. 1299-1310 ◽  
Author(s):  
J. Terada ◽  
G. S. Mitchell
Keyword(s):  
Rem Sleep ◽  
Intermittent Hypoxia ◽  
Neural Control ◽  
Nrem Sleep ◽  
Emg Activity ◽  
Natural Sleep ◽  
Time Control ◽  
Respiratory Plasticity ◽  
Long Term Facilitation

Acute intermittent hypoxia (AIH) elicits a form of respiratory plasticity known as long-term facilitation (LTF). Here, we tested four hypotheses in unanesthetized, spontaneously breathing rats using radiotelemetry for EEG and diaphragm electromyography (Dia EMG) activity: 1) AIH induces LTF in Dia EMG activity; 2) diaphragm LTF (Dia LTF) is more robust during sleep vs. wakefulness; 3) AIH (or repetitive AIH) disrupts natural sleep-wake architecture; and 4) preconditioning with daily AIH (dAIH) for 7 days enhances Dia LTF. Sleep-wake states and Dia EMG were monitored before (60 min), during, and after (60 min) AIH (10, 5-min hypoxic episodes, 5-min normoxic intervals; n = 9), time control (continuous normoxia, n = 8), and AIH following dAIH preconditioning for 7 days (n = 7). Dia EMG activities during quiet wakefulness (QW), rapid eye movement (REM), and non-REM (NREM) sleep were analyzed and normalized to pre-AIH values in the same state. During NREM sleep, diaphragm amplitude (25.1 ± 4.6%), frequency (16.4 ± 4.7%), and minute diaphragm activity (amplitude × frequency; 45.2 ± 6.6%) increased above baseline 0–60 min post-AIH (all P < 0.05). This Dia LTF was less robust during QW and insignificant during REM sleep. dAIH preconditioning had no effect on LTF ( P > 0.05). We conclude that 1) AIH induces Dia LTF during NREM sleep and wakefulness; 2) Dia LTF is greater in NREM sleep vs. QW and is abolished during REM sleep; 3) AIH and repetitive AIH disrupt natural sleep patterns; and 4) Dia LTF is unaffected by dAIH. The capacity for plasticity in spinal pump muscles during sleep and wakefulness suggests an important role in the neural control of breathing.

scholarly journals Toward asleep DBS: cortico-basal ganglia spectral and coherence activity during interleaved propofol/ketamine sedation mimics NREM/REM sleep activity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jing Guang ◽  
Halen Baker ◽  
Orilia Ben-Yishay Nizri ◽  
Shimon Firman ◽  
Uri Werner-Reiss ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Rem Sleep ◽  
Standard Procedure ◽  
Low Frequency ◽  
Nrem Sleep ◽  
Sleep Cycle ◽  
Advanced Parkinson’S Disease ◽  
Low Frequency Power ◽  
The Brain ◽  
Frequency Power

AbstractDeep brain stimulation (DBS) is currently a standard procedure for advanced Parkinson’s disease. Many centers employ awake physiological navigation and stimulation assessment to optimize DBS localization and outcome. To enable DBS under sedation, asleep DBS, we characterized the cortico-basal ganglia neuronal network of two nonhuman primates under propofol, ketamine, and interleaved propofol-ketamine (IPK) sedation. Further, we compared these sedation states in the healthy and Parkinsonian condition to those of healthy sleep. Ketamine increases high-frequency power and synchronization while propofol increases low-frequency power and synchronization in polysomnography and neuronal activity recordings. Thus, ketamine does not mask the low-frequency oscillations used for physiological navigation toward the basal ganglia DBS targets. The brain spectral state under ketamine and propofol mimicked rapid eye movement (REM) and Non-REM (NREM) sleep activity, respectively, and the IPK protocol resembles the NREM-REM sleep cycle. These promising results are a meaningful step toward asleep DBS with nondistorted physiological navigation.

scholarly journals Shining a Light on the Mechanisms of Sleep for Memory Consolidation

2021 ◽  
Author(s):  
Michelle A. Frazer ◽  
Yesenia Cabrera ◽  
Rockelle S. Guthrie ◽  
Gina R. Poe
Keyword(s):  
Rem Sleep ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Strong Support ◽  
Nrem Sleep ◽  
Future Research ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Theta Waves ◽  
Learning Tasks

Abstract Purpose of review This paper reviews all optogenetic studies that directly test various sleep states, traits, and circuit-level activity profiles for the consolidation of different learning tasks. Recent findings Inhibiting or exciting neurons involved either in the production of sleep states or in the encoding and consolidation of memories reveals sleep states and traits that are essential for memory. REM sleep, NREM sleep, and the N2 transition to REM (characterized by sleep spindles) are integral to memory consolidation. Neural activity during sharp-wave ripples, slow oscillations, theta waves, and spindles are the mediators of this process. Summary These studies lend strong support to the hypothesis that sleep is essential to the consolidation of memories from the hippocampus and the consolidation of motor learning which does not necessarily involve the hippocampus. Future research can further probe the types of memory dependent on sleep-related traits and on the neurotransmitters and neuromodulators required.

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