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Ito H, Fukatsu N, Rahaman SM, Mukai Y, Izawa S, Ono D, Kilduff TS, Yamanaka A. Deficiency of orexin signaling during sleep is involved in abnormal REM sleep architecture in narcolepsy. Proc Natl Acad Sci U S A 2023; 120:e2301951120. [PMID: 37796986 PMCID: PMC10576136 DOI: 10.1073/pnas.2301951120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/10/2023] [Indexed: 10/07/2023] Open
Abstract
Narcolepsy is a sleep disorder caused by deficiency of orexin signaling. However, the neural mechanisms by which deficient orexin signaling causes the abnormal rapid eye movement (REM) sleep characteristics of narcolepsy, such as cataplexy and frequent transitions to REM states, are not fully understood. Here, we determined the activity dynamics of orexin neurons during sleep that suppress the abnormal REM sleep architecture of narcolepsy. Orexin neurons were highly active during wakefulness, showed intermittent synchronous activity during non-REM (NREM) sleep, were quiescent prior to the transition from NREM to REM sleep, and a small subpopulation of these cells was active during REM sleep. Orexin neurons that lacked orexin peptides were less active during REM sleep and were mostly silent during cataplexy. Optogenetic inhibition of orexin neurons established that the activity dynamics of these cells during NREM sleep regulate NREM-REM sleep transitions. Inhibition of orexin neurons during REM sleep increased subsequent REM sleep in "orexin intact" mice and subsequent cataplexy in mice lacking orexin peptides, indicating that the activity of a subpopulation of orexin neurons during the preceding REM sleep suppresses subsequent REM sleep and cataplexy. Thus, these results identify how deficient orexin signaling during sleep results in the abnormal REM sleep architecture characteristic of narcolepsy.
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Affiliation(s)
- Hiroto Ito
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Japan Society for the Promotion of Science Research Fellowship for Young Scientists, Tokyo102-0083, Japan
| | - Noriaki Fukatsu
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Sheikh Mizanur Rahaman
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Yasutaka Mukai
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Shuntaro Izawa
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Thomas S. Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA94025
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Chinese Institute for Brain Research, Beijing102206, China
- National Institute for Physiological Sciences, Aichi444-8585, Japan
- National Institutes of Natural Sciences, Aichi444-8585, Japan
- Division of Brain Sciences Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo160-8582, Japan
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Putyora E, Brocklehurst S, Sandilands V. The Effects of Commercially-Relevant Disturbances on Sleep Behaviour in Laying Hens. Animals (Basel) 2023; 13:3105. [PMID: 37835711 PMCID: PMC10571886 DOI: 10.3390/ani13193105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/11/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
Ensuring the welfare of commercially kept animals is a legal and ethical responsibility. Sleep behaviour can be sensitive to environmental perturbations and may be useful in assessing welfare state. The objective of this study was to use behavioural and electrophysiological (EEG) measures to observe the effects of 24 h stressors followed by periods of no stressors on laying hen sleep behaviour, and to investigate the use of sleep behaviour as a means of welfare assessment in commercial poultry. Ten laying hens surgically implanted with EEG devices to record their brain activity over four batches were used. Hens were subjected to undisturbed, disturbed and recovery periods for 24 h. Disturbed periods consisted of either feed deprivation, increased ambient temperature (28 °C) or simulated footpad pain via injection of Freund's adjuvant into the footpad. Sleep state was scored using behaviour data from infrared cameras and EEG data. Over all periods, hens engaged in both SWS (average 60%) and REM sleep (average 12%) during the lights-off period. Feed deprivation and footpad pain had little to no effect on sleep states, while increased ambient temperature significantly reduced REM sleep (to near elimination, p < 0.001) and SWS (p = 0.017). During the lights-on period, footpad pain increased the proportion of time spent resting (p = 0.008) and in SWS (p < 0.001), with feed deprivation or increased ambient temperature (p > 0.05) having no effect. Increasing ambient temperatures are likely to affect sleep and welfare in commercially-kept laying hens in the face of global climate change.
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Affiliation(s)
- Endre Putyora
- Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
- Department of Agriculture, Horticulture and Engineering Sciences, Scotland’s Rural College (SRUC), Edinburgh EH25 9RG, UK;
| | | | - Victoria Sandilands
- Department of Agriculture, Horticulture and Engineering Sciences, Scotland’s Rural College (SRUC), Edinburgh EH25 9RG, UK;
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Jing W, Xia Y, Li M, Cui Y, Chen M, Xue M, Guo D, Biswal BB, Yao D. State-independent and state-dependent patterns in the rat default mode network. Neuroimage 2021; 237:118148. [PMID: 33984491 DOI: 10.1016/j.neuroimage.2021.118148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/04/2021] [Accepted: 05/04/2021] [Indexed: 10/21/2022] Open
Abstract
Resting-state studies have typically assumed constant functional connectivity (FC) between brain regions, and these parameters of interest provide meaningful descriptions of the functional organization of the brain. A number of studies have recently provided evidence pointing to dynamic FC fluctuations in the resting brain, especially in higher-order regions such as the default mode network (DMN). The neural activities underlying dynamic FC remain poorly understood. Here, we recorded electrophysiological signals from DMN regions in freely behaving rats. The dynamic FCs between signals within the DMN were estimated by the phase locking value (PLV) method with sliding time windows across vigilance states [quiet wakefulness (QW) and slow-wave and rapid eye movement sleep (SWS and REMS)]. Factor analysis was then performed to reveal the hidden patterns within the DMN. We identified distinct spatial FC patterns according to the similarities between their temporal dynamics. Interestingly, some of these patterns were vigilance state-dependent, while others were independent across states. The temporal contributions of these patterns fluctuated over time, and their interactive relationships were different across vigilance states. These spatial patterns with dynamic temporal contributions and combinations may offer a flexible framework for efficiently integrating information to support cognition and behavior. These findings provide novel insights into the dynamic functional organization of the rat DMN.
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Affiliation(s)
- Wei Jing
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China; Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China
| | - Yang Xia
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China
| | - Min Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China
| | - Yan Cui
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China
| | - Mingming Chen
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China; School of Electrical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Miaomiao Xue
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China
| | - Daqing Guo
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China
| | - Bharat B Biswal
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China; Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ 07103, United States.
| | - Dezhong Yao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, 2019RU035 Chengdu, China; School of Electrical Engineering, Zhengzhou University, Zhengzhou 450001, China.
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Le Bon O. Relationships between REM and NREM in the NREM-REM sleep cycle: a review on competing concepts. Sleep Med 2020; 70:6-16. [DOI: 10.1016/j.sleep.2020.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/04/2020] [Accepted: 02/06/2020] [Indexed: 01/06/2023]
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Guillaumin MCC, McKillop LE, Cui N, Fisher SP, Foster RG, de Vos M, Peirson SN, Achermann P, Vyazovskiy VV. Cortical region-specific sleep homeostasis in mice: effects of time of day and waking experience. Sleep 2019; 41:4985519. [PMID: 29697841 PMCID: PMC6047413 DOI: 10.1093/sleep/zsy079] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/19/2018] [Indexed: 12/21/2022] Open
Abstract
Sleep–wake history, wake behaviors, lighting conditions, and circadian time influence sleep, but neither their relative contribution nor the underlying mechanisms are fully understood. The dynamics of electroencephalogram (EEG) slow-wave activity (SWA) during sleep can be described using the two-process model, whereby the parameters of homeostatic Process S are estimated using empirical EEG SWA (0.5–4 Hz) in nonrapid eye movement sleep (NREMS), and the 24 hr distribution of vigilance states. We hypothesized that the influence of extrinsic factors on sleep homeostasis, such as the time of day or wake behavior, would manifest in systematic deviations between empirical SWA and model predictions. To test this hypothesis, we performed parameter estimation and tested model predictions using NREMS SWA derived from continuous EEG recordings from the frontal and occipital cortex in mice. The animals showed prolonged wake periods, followed by consolidated sleep, both during the dark and light phases, and wakefulness primarily consisted of voluntary wheel running, learning a new motor skill or novel object exploration. Simulated SWA matched empirical levels well across conditions, and neither waking experience nor time of day had a significant influence on the fit between data and simulation. However, we consistently observed that Process S declined during sleep significantly faster in the frontal than in the occipital area of the neocortex. The striking resilience of the model to specific wake behaviors, lighting conditions, and time of day suggests that intrinsic factors underpinning the dynamics of Process S are robust to extrinsic influences, despite their major role in shaping the overall amount and distribution of vigilance states across 24 hr.
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Affiliation(s)
| | - Laura E McKillop
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nanyi Cui
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Simon P Fisher
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Russell G Foster
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Maarten de Vos
- Department of Engineering Science, University of Oxford, Headington, United Kingdom
| | - Stuart N Peirson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Peter Achermann
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Jing W, Wang Y, Fang G, Chen M, Xue M, Guo D, Yao D, Xia Y. EEG Bands of Wakeful Rest, Slow-Wave and Rapid-Eye-Movement Sleep at Different Brain Areas in Rats. Front Comput Neurosci 2016; 10:79. [PMID: 27536231 PMCID: PMC4971061 DOI: 10.3389/fncom.2016.00079] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/19/2016] [Indexed: 12/02/2022] Open
Abstract
Accumulating evidence reveals that neuronal oscillations with various frequency bands in the brain have different physiological functions. However, the frequency band divisions in rats were typically based on empirical spectral distribution from limited channels information. In the present study, functionally relevant frequency bands across vigilance states and brain regions were identified using factor analysis based on 9 channels EEG signals recorded from multiple brain areas in rats. We found that frequency band divisions varied both across vigilance states and brain regions. In particular, theta oscillations during REM sleep were subdivided into two bands, 5–7 and 8–11 Hz corresponding to the tonic and phasic stages, respectively. The spindle activities of SWS were different along the anterior-posterior axis, lower oscillations (~16 Hz) in frontal regions and higher in parietal (~21 Hz). The delta and theta activities co-varied in the visual and auditory cortex during wakeful rest. In addition, power spectra of beta oscillations were significantly decreased in association cortex during REM sleep compared with wakeful rest. These results provide us some new insights into understand the brain oscillations across vigilance states, and also indicate that the spatial factor should not be ignored when considering the frequency band divisions in rats.
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Affiliation(s)
- Wei Jing
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Yanran Wang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Guangzhan Fang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences Chengdu, China
| | - Mingming Chen
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Miaomiao Xue
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Daqing Guo
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Yang Xia
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
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Abstract
A commonly held view is that extended wakefulness is causal for a broad spectrum of deleterious effects at molecular, cellular, network, physiological, psychological, and behavioral levels. Consequently, it is often presumed that sleep plays an active role in providing renormalization of the changes incurred during preceding waking. Not surprisingly, unequivocal empirical evidence supporting such a simple bi-directional interaction between waking and sleep is often limited or controversial. One difficulty is that, invariably, a constellation of many intricately interrelated factors, including the time of day, specific activities or behaviors during preceding waking, metabolic status and stress are present at the time of measurement, shaping the overall effect observed. In addition to this, although insufficient or disrupted sleep is thought to prevent efficient recovery of specific physiological variables, it is also often difficult to attribute specific changes to the lack of sleep proper. Furthermore, sleep is a complex phenomenon characterized by a multitude of processes, whose unique and distinct contributions to the purported functions of sleep are difficult to determine, because they are interrelated. Intensive research effort over the last decades has greatly progressed current understanding of the cellular and physiological processes underlying the regulation of vigilance states. Notably, it also highlighted the infinite complexity within both waking and sleep, and revealed a number of fundamental conceptual and technical obstacles that need to be overcome in order to fully understand these processes. A promising approach could be to view sleep not as an entity, which has specific function(s) and is subject to direct regulation, but as a manifestation of the process of metaregulation, which enables efficient moment-to-moment integration between internal and external factors, preceding history and current homeostatic needs.
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Vyazovskiy VV, Delogu A. NREM and REM Sleep: Complementary Roles in Recovery after Wakefulness. Neuroscientist 2014; 20:203-19. [PMID: 24598308 DOI: 10.1177/1073858413518152] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The overall function of sleep is hypothesized to provide "recovery" after preceding waking activities, thereby ensuring optimal functioning during subsequent wakefulness. However, the functional significance of the temporal dynamics of sleep, manifested in the slow homeostatic process and the alternation between non-rapid eye movement (NREM) and REM sleep remains unclear. We propose that NREM and REM sleep have distinct and complementary contributions to the overall function of sleep. Specifically, we suggest that cortical slow oscillations, occurring within specific functionally interconnected neuronal networks during NREM sleep, enable information processing, synaptic plasticity, and prophylactic cellular maintenance ("recovery process"). In turn, periodic excursions into an activated brain state-REM sleep-appear to be ideally placed to perform "selection" of brain networks, which have benefited from the process of "recovery," based on their offline performance. Such two-stage modus operandi of the sleep process would ensure that its functions are fulfilled according to the current need and in the shortest time possible. Our hypothesis accounts for the overall architecture of normal sleep and opens up new perspectives for understanding pathological conditions associated with abnormal sleep patterns.
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Affiliation(s)
| | - Alessio Delogu
- Department of Neuroscience, Institute of Psychiatry, King's College London, London, UK
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Le Bon O, Linkowski P. Absence of systematic relationships between REMS duration episodes and spectral power Delta and Ultra-Slow bands in contiguous NREMS episodes in healthy humans. J Neurophysiol 2013; 110:162-9. [DOI: 10.1152/jn.00020.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies in animals and humans have reported correlations between the durations of rapid eye movement sleep (REMS) episodes and immediately preceding or subsequent non-REMS (NREMS) episodes. The relationship between these two types of sleep is a crucial component in understanding the regulation and neurophysiology of ultradian alternations that occur during sleep. Although the present study replicated previous studies, we also measured NREMS in terms of spectral power Delta and Ultra-Slow bands in addition to duration in examining correlations. The spectral power Delta band, also known as slow-wave activity, measures sleep quantity and is believed to reflect sleep physiology better than mere episode durations. The Ultra-Slow spectral power band was analyzed in parallel. Healthy human participants of both sexes ( n = 26, age range 15–45 yr, n = 12 female) were carefully selected to participate in two consecutive series of home polysomnograms performed after 2 nights of habituation to the equipment. In the analyses, REMS episode durations (minutes) were compared with immediately preceding and immediately subsequent NREMS episodes (Delta and Ultra-Slow power) in each sleep cycle. REMS episode duration was more strongly correlated with preceding NREMS episodes than with subsequent NREMS episodes. However, in most cases, no correlations were observed in either direction. One ultradian sleep regulation hypothesis, which is based on stronger correlations between REMS and subsequent NREMS episode durations, holds that the main purpose of REMS is to reactivate NREMS during each sleep cycle. The present results do not support that hypothesis.
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Affiliation(s)
- O. Le Bon
- Sleep Unit, Tivoli University Hospital and Laboratory of Psychiatric Research, Faculty of Medecine, Université Libre de Bruxelles, Brussels, Belgium; and
| | - P. Linkowski
- Department of Psychiatry, Erasme Hospital, Laboratory of Psychiatric Research Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
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Polta SA, Fenzl T, Jakubcakova V, Kimura M, Yassouridis A, Wotjak CT. Prognostic and symptomatic aspects of rapid eye movement sleep in a mouse model of posttraumatic stress disorder. Front Behav Neurosci 2013; 7:60. [PMID: 23750131 PMCID: PMC3668327 DOI: 10.3389/fnbeh.2013.00060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 05/19/2013] [Indexed: 01/08/2023] Open
Abstract
Not every individual develops Posttraumatic Stress Disorder (PTSD) after the exposure to a potentially traumatic event. Therefore, the identification of pre-existing risk factors and early diagnostic biomarkers is of high medical relevance. However, no objective biomarker has yet progressed into clinical practice. Sleep disturbances represent commonly reported complaints in PTSD patients. In particular, changes in rapid eye movement sleep (REMS) properties are frequently observed in PTSD patients. Here, we examined in a mouse model of PTSD whether (1) mice developed REMS alterations after trauma and (2) whether REMS architecture before and/or shortly after trauma predicted the development of PTSD-like symptoms. We monitored sleep-wake behavior via combined electroencephalogram/electromyogram recordings immediately before (24 h pre), immediately after (0-48 h post) and 2 months after exposure to an electric foot shock in male C57BL/6N mice (n = 15). PTSD-like symptoms, including hyperarousal, contextual, and generalized fear, were assessed 1 month post-trauma. Shocked mice showed early onset and sustained elevation of REMS compared to non-shocked controls. In addition, REMS architecture before trauma was correlated with the intensity of acoustic startle responses, but not contextual fear, 1 month after trauma. Our data suggest REMS as prognostic (pre-trauma) and symptomatic (post-trauma) marker of PTSD-like symptoms in mice. Translated to the situation in humans, REMS may constitute a viable, objective, and non-invasive biomarker in PTSD and other trauma-related psychiatric disorders, which could guide pharmacological interventions in humans at high risk.
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Horne J. Why REM sleep? Clues beyond the laboratory in a more challenging world. Biol Psychol 2013; 92:152-68. [DOI: 10.1016/j.biopsycho.2012.10.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 09/17/2012] [Accepted: 10/11/2012] [Indexed: 11/16/2022]
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Blagrove M, Fouquet NC, Baird AL, Pace-Schott EF, Davies AC, Neuschaffer JL, Henley-Einion JA, Weidemann CT, Thome J, McNamara P, Turnbull OH. Association of salivary-assessed oxytocin and cortisol levels with time of night and sleep stage. J Neural Transm (Vienna) 2012; 119:1223-32. [DOI: 10.1007/s00702-012-0880-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/25/2012] [Indexed: 02/06/2023]
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Rosales-Lagarde A, Armony JL, del Río-Portilla Y, Trejo-Martínez D, Conde R, Corsi-Cabrera M. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study. Front Behav Neurosci 2012; 6:25. [PMID: 22719723 PMCID: PMC3376727 DOI: 10.3389/fnbeh.2012.00025] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/24/2012] [Indexed: 11/13/2022] Open
Abstract
Converging evidence from animal and human studies suggest that rapid eye movement (REM) sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation (REM-D) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM-D, by awakening them at each REM sleep onset, or non-rapid eye movement sleep interruptions (NREM-I) as control for potential non-specific effects of awakenings and lack of sleep. In a within-subject design, a visual emotional reactivity task was performed in the scanner before and 24 h after sleep manipulation. Behaviorally, emotional reactivity was enhanced relative to baseline (BL) in the REM deprived group only. In terms of fMRI signal, there was, as expected, an overall decrease in activity in the NREM-I group when subjects performed the task the second time, particularly in regions involved in emotional processing, such as occipital and temporal areas, as well as in the ventrolateral prefrontal cortex, involved in top-down emotion regulation. In contrast, activity in these areas remained the same level or even increased in the REM-D group, compared to their BL level. Taken together, these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity, both at behavioral and neural levels, and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness.
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Affiliation(s)
- Alejandra Rosales-Lagarde
- Faculty of Psychology, Laboratory of Sleep, Universidad Nacional Autónoma de MéxicoMéxico DF, México
| | - Jorge L. Armony
- Department of Psychiatry, McGill University and Douglas Mental Health University Institute, MontrealQC, Canada
| | - Yolanda del Río-Portilla
- Faculty of Psychology, Laboratory of Sleep, Universidad Nacional Autónoma de MéxicoMéxico DF, México
| | - David Trejo-Martínez
- Module of Neuroimage and Cognition, Hospital Ángeles del PedregalMexico City, Mexico
| | - Ruben Conde
- Module of Neuroimage and Cognition, Hospital Ángeles del PedregalMexico City, Mexico
| | - Maria Corsi-Cabrera
- Faculty of Psychology, Laboratory of Sleep, Universidad Nacional Autónoma de MéxicoMéxico DF, México
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The end of sleep: 'sleep debt' versus biological adaptation of human sleep to waking needs. Biol Psychol 2010; 87:1-14. [PMID: 20955760 DOI: 10.1016/j.biopsycho.2010.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/14/2010] [Accepted: 10/07/2010] [Indexed: 01/02/2023]
Abstract
It is argued that the latter part of usual human sleep is phenotypically adaptable (without 'sleep debt') to habitual shortening or lengthening, according to environmental influences of light, safety, food availability and socio-economic factors, but without increasing daytime sleepiness. Pluripotent brain mechanisms linking sleep, hunger, foraging, locomotion and alertness, facilitate this time management, with REM acting as a 'buffer' between wakefulness and nonREM ('true') sleep. The adaptive sleep range is approximately 6-9h, although, a timely short (<20 min) nap can equate to 1h 'extra' nighttime sleep. Appraisal of recent epidemiological findings linking habitual sleep duration to mortality and morbidity points to nominal causal effects of sleep within this range. Statistical significance, here, may not equate to real clinical significance. Sleep durations outside 6-9h are usually surrogates of common underlying causes, with sleep associations taking years to develop. Manipulation of sleep, alone, is unlikely to overcome these health effects, and there are effective, rapid, non-sleep, behavioural countermeasures. Sleep can be taken for pleasure, with minimal sleepiness; such 'sleepability' is 'unmasked' by sleep-conducive situations. Sleep is not the only anodyne to sleepiness, but so is wakefulness, inasmuch that some sleepiness disappears when wakefulness becomes more challenging and eventful. A more ecological approach to sleep and sleepiness is advocated.
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Is sleep in animals affected by prior waking experiences? Anim Welf 2010. [DOI: 10.1017/s0962728600001597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
AbstractMethods to assess changes in the mental state of animals in response to their environment can be used to provide information to enhance animal welfare. One of the most profound changes of mental state observable in mammals is the change between wakefulness and sleep. Sleeping mammals have characteristics that are similar to one another and are measurable, such as specific behaviours, changes in responsiveness to external stimuli and changes in electrophysiology and neurochemistry. Although sleep is a ubiquitous behaviour in the life of mammals, there has been relatively little research on this topic in domesticated animals. All animals are motivated to sleep and this motivation increases after a prolonged period of wakefulness. In humans, sleep can be affected by what has occurred in the prior period of wakefulness and this has also been demonstrated in some non-human mammals. An important aspect of human sleep medicine is the association between stress and subsequent sleep disturbances. Studying changes in amount, bout length, distribution or type of sleep after exposure to potentially stressful events, could help us understand how animals respond to changes in their environment. It is possible that different types of stressors could affect sleep characteristics in different ways and that monitoring and identifying these changes could be useful in providing an additional way of identifying management procedures that have the potential to affect welfare. Sleep measurement is a potentially valuable tool in studies to assess animal welfare.
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Abstract
Understanding dreams has long been considered fundamental to the development of a theory of consciousness. Evidence from neurobiology and neuroimaging research has paved the way for new theories of dreaming that are empirically supported. In this article we argue that dreaming is a unique state of consciousness that incorporates 3 temporal dimensions: experience of the present, processing of the past, and preparation for the future. The temporal complexity of dreams is made possible in part by the unique neurobiological environment of sleep, in which stimuli are internally generated and many of the restrictions associated with waking thought are absent. Because dream consciousness is not determined by sensory stimuli, a flexible integration of past experiences and the forging of novel connections are possible. We argue that disparate dream theories may not be mutually exclusive but rather relate to different temporal domains of the dream state.
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Characterization of the sleep architecture in two species of fruit bat. Behav Brain Res 2010; 208:497-501. [PMID: 20043956 DOI: 10.1016/j.bbr.2009.12.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 12/15/2009] [Accepted: 12/21/2009] [Indexed: 10/20/2022]
Abstract
Bats (Chiroptera) are the second-most abundant mammalian order in the world, occupying a diverse range of habitats and exhibiting many different life history traits. In order to contribute to this highly underrepresented group we describe the sleep architecture of two species of frugivorous bat, the greater short-nosed fruit bat (Cynopterus sphinx) and the lesser dawn fruit bat (Eonycteris spelaea). Electroencephalogram (EEG) and electromyogram (EMG) data were recorded from multiple individuals (>or=5) by telemetry over a 72-h period in a laboratory setting with light/dark cycles equivalent to those found in the wild. Our results show that over a 24-h period both species spent more time asleep than awake (mean 15 h), less than previous reported for Chiroptera (20 h). C. sphinx spent significantly more of its non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM) quotas during the light phase, while E. spelaea divided its sleep-wake architecture equally between both light and dark phases. Comparing the sleep patterns of the two species found that C. sphinx had significantly fewer NREM and REM episodes than E. spelaea but each episode lasted for a significantly longer period of time. Potential hypotheses to explain the differences in the sleep architecture of C. sphinx with E. spelaea, including risk of predation and social interaction are discussed.
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Abstract
The idea that sleep might be involved in brain plasticity has been investigated for many years through a large number of animal and human studies, but evidence remains fragmentary. Large amounts of sleep in early life suggest that sleep may play a role in brain maturation. In particular, the influence of sleep in developing the visual system has been highlighted. The current data suggest that both Rapid Eye Movement (REM) and non-REM sleep states would be important for brain development. Such findings stress the need for optimal paediatric sleep management. In the adult brain, the role of sleep in learning and memory is emphasized by studies at behavioural, systems, cellular and molecular levels. First, sleep amounts are reported to increase following a learning task and sleep deprivation impairs task acquisition and consolidation. At the systems level, neurophysiological studies suggest possible mechanisms for the consolidation of memory traces. These imply both thalamocortical and hippocampo-neocortical networks. Similarly, neuroimaging techniques demonstrated the experience-dependent changes in cerebral activity during sleep. Finally, recent works show the modulation during sleep of cerebral protein synthesis and expression of genes involved in neuronal plasticity.
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Affiliation(s)
- T T Dang-Vu
- Cyclotron Research Centre, University of Liege, Belgium.
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REM sleep, energy balance and ‘optimal foraging’. Neurosci Biobehav Rev 2009; 33:466-74. [DOI: 10.1016/j.neubiorev.2008.12.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 11/30/2008] [Accepted: 12/08/2008] [Indexed: 11/21/2022]
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Le Bon O, Hoffmann R, Staner L, Armitage R. Relationships between the number of ultradian cycles and key sleep variables in outpatients with major depressive disorder. Psychiatry Res 2009; 165:60-7. [PMID: 19046605 DOI: 10.1016/j.psychres.2007.08.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 07/08/2007] [Accepted: 08/18/2007] [Indexed: 11/26/2022]
Abstract
The regulation of the alternation between rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS) is still a matter of much debate. It is also an important topic for psychiatric research, since both sleep components show anomalies in Major Depressive Disorders (MDD) and related syndromes. In previous studies on healthy controls, we showed preferential links of the number of ultradian cycles with REMS-related variables rather than with NREMS-related variables. REMS Latency (RL), for example, was shown to be inversely related to the number of cycles. The present study replicates these analyses in a group of 29 patients with MDD (age range: 23-56; 16 females), after two adaptation nights. Results showed significant correlations between the number of cycles and REMS, and between the number of cycles and RL, whereas correlations with NREMS were not significant. This indirectly supports regulation hypotheses considering REMS as the main focus of the oscillation, inhibiting and interrupting NREMS. Also, when the RL is shorter, there are more ultradian cycles than when the RL is long. This adds an interesting element in the elucidation of the physiological meaning of anomalies of RL.
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Affiliation(s)
- Olivier Le Bon
- CHU Tivoli, Department of Psychiatry, Université Libre de Bruxelles, av. Max Buset 34, 7100 La Louvière, Belgium.
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Amici R, Cerri M, Ocampo-Garcés A, Baracchi F, Dentico D, Jones CA, Luppi M, Perez E, Parmeggiani PL, Zamboni G. Cold exposure and sleep in the rat: REM sleep homeostasis and body size. Sleep 2008; 31:708-15. [PMID: 18517040 DOI: 10.1093/sleep/31.5.708] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES Exposure to low ambient temperature (Ta) depresses REM sleep (REMS) occurrence. In this study, both short and long-term homeostatic aspects of REMS regulation were analyzed during cold exposure and during subsequent recovery at Ta 24 degrees C. DESIGN EEG activity, hypothalamic temperature, and motor activity were studied during a 24-h exposure to Tas ranging from 10 degrees C to -10 degrees C and for 4 days during recovery. SETTING Laboratory of Physiological Regulation during the Wake-Sleep Cycle, Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna. SUBJECTS 24 male albino rats. INTERVENTIONS Animals were implanted with electrodes for EEG recording and a thermistor to measure hypothalamic temperature. MEASUREMENTS AND RESULTS REMS occurrence decreased proportionally with cold exposure, but a fast compensatory REMS rebound occurred during the first day of recovery when the previous loss went beyond a "fast rebound" threshold corresponding to 22% of the daily REMS need. A slow REMS rebound apparently allowed the animals to fully restore the previous REMS loss during the following 3 days of recovery. CONCLUSION Comparing the present data on rats with data from earlier studies on cats and humans, it appears that small mammals have less tolerance for REMS loss than large ones. In small mammals, this low tolerance may be responsible on a short-term basis for the shorter wake-sleep cycle, and on long-term basis, for the higher percentage of REMS that is quickly recovered following REMS deprivation.
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Affiliation(s)
- Roberto Amici
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Italy.
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Hatzinger M, Brand S, Perren S, Stadelmann S, von Wyl A, von Klitzing K, Holsboer-Trachsler E. Electroencephalographic sleep profiles and hypothalamic-pituitary-adrenocortical (HPA)-activity in kindergarten children: early indication of poor sleep quality associated with increased cortisol secretion. J Psychiatr Res 2008; 42:532-43. [PMID: 17645894 DOI: 10.1016/j.jpsychires.2007.05.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/15/2007] [Accepted: 05/22/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVES In children, objective data carried out from sleep EEG monitoring are scarce. Furthermore, results associating the hypothalamic-pituitary-adrenocortical (HPA)-activity with sleep EEG measurements in children are missing. Therefore, our study aimed to investigate in preschool-children the association between sleep patterns and endocrine activity. Furthermore, children's behavioral/emotional difficulties and competences were assessed in order to correlate psychological strain with sleep measures. PARTICIPANTS AND METHODS Sixty-seven kindergarten children (35 boys and 32 girls) aged 5.34 underwent EEG-monitoring for one night. For baseline HPA-activity assessment, saliva samples were collected immediately after awakening, whereas saliva samples before, while and after a psychological challenge were used to assess the HPA-activity under stress conditions. RESULTS Compared to girls, boys showed significantly more REM sleep time. After cluster analysis, children labeled as 'poor' sleepers (n=27; 40,30%) showed significantly increased morning cortisol values, as compared to 'good' sleepers (n=22; 32,83%). Furthermore, increased cortisol AUC values under stress conditions were significantly associated with an elevated number of awakenings after sleep onset, and more sleep time in stages 1 and 2. In addition, an increased sleep efficiency was significantly correlated with self-reported emotional/behavioral difficulties, i.e. with low degrees of impulsivity (r=-.31; p<.05) and lower degrees of social inhibition and peer victimiziation (r=-.26, p<.05). CONCLUSIONS Our results underlined that already in preschool years, associations between objectively examined unfavorable sleep patterns, increased HPA-system activity and more difficult behavioral and psychosocial dimensions may be observed.
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Affiliation(s)
- Martin Hatzinger
- Psychiatric Out-Patient Department, University Hospital Basel, Switzerland.
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LAHL OLAF, WISPEL CHRISTIANE, WILLIGENS BERNADETTE, PIETROWSKY REINHARD. An ultra short episode of sleep is sufficient to promote declarative memory performance. J Sleep Res 2008; 17:3-10. [DOI: 10.1111/j.1365-2869.2008.00622.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Hornung OP, Regen F, Danker-Hopfe H, Schredl M, Heuser I. The relationship between REM sleep and memory consolidation in old age and effects of cholinergic medication. Biol Psychiatry 2007; 61:750-7. [PMID: 17141741 DOI: 10.1016/j.biopsych.2006.08.034] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 05/31/2006] [Accepted: 08/28/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Recent findings in young adults suggest that rapid eye movement (REM) sleep plays a role in procedural memory consolidation. The significance of REM sleep for memory consolidation in old age has not yet been investigated. METHODS Effects of REM sleep manipulation on declarative and procedural memory consolidation were investigated in 107 healthy older adults, ages 60-82 years. Rapid eye movement sleep deprivation was achieved by REM sleep awakenings and compared with non-REM sleep awakenings. Rapid eye movement sleep augmentation was realized physiologically by REM sleep rebound and pharmacologically by administering an acetylcholinesterase inhibitor in a double-blind, placebo-controlled design. Memory performance was tested by a paired associate list and a mirror tracing task at 9:30 pm and 7:30 am with sleep intervening between 11:00 pm and 7:00 am. RESULTS Although REM sleep deprivation led to a significant reduction in total and phasic REM sleep, memory consolidation remained unaffected. Both REM sleep augmentation groups showed a significant increase in phasic REM sleep, whereas only pharmacological cholinergic REM sleep manipulation exerted a significant positive effect on procedural memory consolidation. CONCLUSIONS Because only after cholinergic stimulation of phasic REM sleep procedural memory consolidation is improved, cholinergic activation seems to be a crucial component of REM sleep-related memory consolidation in old age.
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Affiliation(s)
- Orla P Hornung
- Department of Psychiatry and Psychotherapy, Charité-University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany.
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Abstract
The following review examines the evidence for sleep in flying birds. The daily need to sleep in most animals has led to the common belief that birds, such as the common swift (Apus apus), which spend the night on the wing, sleep in flight. The electroencephalogram (EEG) recordings required to detect sleep in flight have not been performed, however, rendering the evidence for sleep in flight circumstantial. The neurophysiology of sleep and flight suggests that some types of sleep might be compatible with flight. As in mammals, birds exhibit two types of sleep, slow-wave sleep (SWS) and rapid eye-movement (REM) sleep. Whereas, SWS can occur in one or both brain hemispheres at a time, REM sleep only occurs bihemispherically. During unihemispheric SWS, the eye connected to the awake hemisphere remains open, a state that may allow birds to visually navigate during sleep in flight. Bihemispheric SWS may also be possible during flight when constant visual monitoring of the environment is unnecessary. Nevertheless, the reduction in muscle tone that usually accompanies REM sleep makes it unlikely that birds enter this state in flight. Upon landing, birds may need to recover the components of sleep that are incompatible with flight. Periods of undisturbed postflight recovery sleep may be essential for maintaining adaptive brain function during wakefulness. The recent miniaturization of EEG recording devices now makes it possible to measure brain activity in flight. Determining if and how birds sleep in flight will contribute to our understanding of a largely unexplored aspect of avian behavior and may also provide insight into the function of sleep.
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Affiliation(s)
- Niels C Rattenborg
- Max-Planck-Institute for Ornithology-Seewiesen, Postfach 1564, D-82305, Starnberg, Germany.
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Lesku JA, Roth TC, Amlaner CJ, Lima SL. A Phylogenetic Analysis of Sleep Architecture in Mammals: The Integration of Anatomy, Physiology, and Ecology. Am Nat 2006; 168:441-53. [PMID: 17004217 DOI: 10.1086/506973] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 05/30/2006] [Indexed: 11/03/2022]
Abstract
Among mammalian species, the time spent in the two main "architectural" states of sleep--slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep--varies greatly. Previous comparative studies of sleep architecture found that larger mammals, those with bigger brains, and those with higher absolute basal metabolic rates (BMR) tended to engage in less SWS and REM sleep. Species experiencing a greater risk of predation also exhibited less SWS and REM sleep. In all cases, however, these studies lacked a formal phylogenetic and theoretical framework and used mainly correlational analyses. Using independent contrasts and an updated data set, we extended existing approaches with path analysis to examine the integrated influence of anatomy, physiology, and ecology on sleep architecture. Path model structure was determined by nonmutually exclusive hypotheses for the function of sleep. We found that species with higher relative BMRs engage in less SWS, whereas species with larger relative brain masses engage in more REM sleep. REM sleep was the only sleep variable strongly influenced by predation risk; mammals sleeping in riskier environments engage in less REM sleep. Overall, we found support for some hypotheses for the function of sleep, such as facilitating memory consolidation or learning, but not others, such as energy conservation.
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Affiliation(s)
- John A Lesku
- Department of Ecology and Organismal Biology, Indiana State University, Terre Haute, Indiana 47809, USA.
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28
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Hornung OP, Regen F, Schredl M, Heuser I, Danker-Hopfe H. Manipulating REM sleep in older adults by selective REM sleep deprivation and physiological as well as pharmacological REM sleep augmentation methods. Exp Neurol 2005; 197:486-94. [PMID: 16289171 DOI: 10.1016/j.expneurol.2005.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/11/2005] [Accepted: 10/14/2005] [Indexed: 11/22/2022]
Abstract
Experimental approaches to manipulate REM sleep within the cognitive neuroscience of sleep are usually based on sleep deprivation paradigms and focus on younger adults. In the present study, a traditional selective REM sleep deprivation paradigm as well as two alternative manipulation paradigms targeting REM sleep augmentation were investigated in healthy older adults. The study sample consisted of 107 participants, male and female, between the ages of 60 and 82 years, who had been randomly assigned to five experimental groups. During the study night, a first group was deprived of REM sleep by selective REM sleep awakenings, while a second group was woken during stage 2 NREM sleep in matched frequency. Physiological REM sleep augmentation was realized by REM sleep rebound after selective REM sleep deprivation, pharmacological REM sleep augmentation by administering an acetylcholinesterase inhibitor in a double-blind, placebo-controlled design. Deprivation and augmentation paradigms manipulated REM sleep significantly, the former affecting more global measures such as REM sleep minutes and percentage, the latter more organizational aspects such as stage shifts to REM sleep, REM latency, REM density (only pharmacological augmentation) and phasic REM sleep duration. According to our findings, selective REM sleep deprivation seems to be an efficient method of REM sleep manipulation in healthy older adults. While physiological rebound-based and pharmacological cholinergic REM sleep augmentation methods both failed to affect global measures of REM sleep, their efficiency in manipulating organizational aspects of REM sleep extends the traditional scope of REM sleep manipulation methods within the cognitive neuroscience of sleep.
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Affiliation(s)
- Orla P Hornung
- Department of Psychiatry and Psychotherapy, Charité-University Medicine Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
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Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. ACTA ACUST UNITED AC 2005; 49:455-71. [PMID: 16269314 DOI: 10.1016/j.brainresrev.2005.01.006] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 11/17/2004] [Accepted: 01/12/2005] [Indexed: 11/29/2022]
Abstract
Our understanding of when the fetus can experience pain has been largely shaped by neuroanatomy. However, completion of the cortical nociceptive connections just after mid-gestation is only one part of the story. In addition to critically reviewing evidence for whether the fetus is ever awake or aware, and thus able to truly experience pain, we examine the role of endogenous neuro-inhibitors, such as adenosine and pregnanolone, produced within the feto-placental unit that contribute to fetal sleep states, and thus mediate suppression of fetal awareness. The uncritical view that the nature of presumed fetal pain perception can be assessed by reference to the prematurely born infant is challenged. Rigorously controlled studies of invasive procedures and analgesia in the fetus are required to clarify the impact of fetal nociception on postnatal pain sensitivity and neural development, and the potential benefits or harm of using analgesia in this unique setting.
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Affiliation(s)
- David J Mellor
- Riddet Centre and Institute of Food, Nutrition and Human Health, College of Sciences, Massey University, Palmerston North, New Zealand.
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30
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Abstract
The functions of mammalian sleep remain unclear. Most theories suggest a role for non-rapid eye movement (NREM) sleep in energy conservation and in nervous system recuperation. Theories of REM sleep have suggested a role for this state in periodic brain activation during sleep, in localized recuperative processes and in emotional regulation. Across mammals, the amount and nature of sleep are correlated with age, body size and ecological variables, such as whether the animals live in a terrestrial or an aquatic environment, their diet and the safety of their sleeping site. Sleep may be an efficient time for the completion of a number of functions, but variations in sleep expression indicate that these functions may differ across species.
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Affiliation(s)
- Jerome M Siegel
- Neurobiology Research 151A3, VA GLAHS Sepulveda, Department of Psychiatry and Brain Research Institute, UCLA School of Medicine, North Hills, California 91343, USA.
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31
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Le Bon O, Chabanski S, Dramaix M, Staner L, Pelc I, Linkowski P. Inverse association between Slow Wave Activity per cycle and the number of ultradian sleep cycles per night in healthy humans. Clin Neurophysiol 2005; 116:1493-500. [PMID: 15899592 DOI: 10.1016/j.clinph.2005.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2003] [Revised: 03/05/2005] [Accepted: 03/09/2005] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Comparisons of sleep Slow Wave Activity (SWA) during successive sleep cycles rely on the assumption that SWA in a given cycle is independent of the number of ultradian cycles present in a night. This assumption was evaluated here. METHODS Twenty-six healthy controls with no medical, sleep or psychiatric disorders were selected among 84 candidates and their sleep was recorded at home across 2 consecutive nights after two habituation nights. RESULTS In comparison with nights with less cycles, nights with more cycles showed significantly more REMS but not more NREMS. No correlation was found between the number of cycles and the integrated SWA per night (epochs visually scored as NREMS). However, inverse correlations were found between the number of cycles and the SWA per cycle. This was significant on both nights in Cycle 1 and strong trends were found for the two subsequent cycles on Night 2. Comparable results were found after removal of nights containing suspected Skipped First REMS episodes. CONCLUSIONS The SWA in a cycle was found to be inversely correlated to the number of cycles in the first 3 cycles in at least one of the two analyzed nights. SIGNIFICANCE Differences in the number of cycles per night are a potential bias in the comparisons of SWA per cycles.
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Affiliation(s)
- Olivier Le Bon
- Sleep Research Unit, Brugmann University Hospital, Université Libre de Bruxelles, CHU Brugmann S78, Place Van Gehuchten 4, 1020 Bruxelles, Belgium.
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Abstract
We discuss several lines of evidence refuting the hypothesis that procedural or declarative memories are processed/consolidated in sleep. One of the strongest arguments against a role for sleep in declarative memory involves the demonstration that the marked suppression or elimination of REM sleep in subjects on antidepressant drugs or with brainstem lesions produces no detrimental effects on cognition. Procedural memory, like declarative memory, undergoes a slow, time-dependent period of consolidation. A process has recently been described wherein performance on some procedural tasks improves with the mere passage of time and has been termed "enhancement." Some studies, but not others, have reported that the consolidation/enhancement of perceptual and motor skills is dependent on sleep. We suggest that consolidation or enhancement, initiated in waking with task acquisition, could in some instances extend to sleep, but sleep would serve no unique role in these processes. In sum, there is no compelling evidence to support a relationship between sleep and memory consolidation.
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Affiliation(s)
- Robert P Vertes
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
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Reix P, Arsenault J, Langlois C, Niyonsenga T, Praud JP. Nonnutritive swallowing and respiration relationships in preterm lambs. J Appl Physiol (1985) 2004; 97:1283-90. [PMID: 15180969 DOI: 10.1152/japplphysiol.00060.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to assess the effects of the different states of alertness on 1) nonnutritive swallowing (NNS) frequency, 2) the relationship between NNS and the respiratory cycle, and 3) the association of NNS with spontaneous apneas. Recordings of sleep states, diaphragm and laryngeal constrictor electrical activity, nasal flow, electrocardiogram, respiratory inductance plethysmography, and pulse oximetry were obtained from six preterm lambs without sedation. Analysis of 2,468 NNS showed that 1) NNS frequency was higher during quiet wakefulness and active sleep (AS) than in quiet sleep; 2) in all states of alertness, a greater number of NNS (38%) were preceded and followed by an inspiration; 3) although NNS and central apneas were rarely coincidental, AS appeared to favor their association; and 4) most obstructive apneas occurred in AS and were coincidental with bursts of NNS. Compared with results in full-term lambs, premature birth does not modify the NNS-respiratory coordination. However, AS in preterm lambs is characterized by a higher association of NNS bursts with obstructive apneas.
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Affiliation(s)
- Philippe Reix
- Dept. of Pediatrics, Univ. of Sherbrooke, Sherbrooke, PQ, Canada J1H 5N4
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Ferini-Strambi L, Ortelli P, Castronovo V, Cappa S. Increased periodic arousal fluctuations during non-REM sleep are associated to superior memory. Brain Res Bull 2004; 63:439-42. [PMID: 15249108 DOI: 10.1016/j.brainresbull.2004.01.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Revised: 12/12/2003] [Accepted: 01/20/2004] [Indexed: 11/26/2022]
Abstract
Sleep has been implicated in the plastic cerebral changes that underlie learning and memory. The scientific investigation of people with exceptional memory has been relatively neglected. We report the results of a polysomnographic investigation of an individual with superior memory performance. The sleep structure, in terms of sleep induction and maintenance, as well as non-REM and REM sleep percentages, were normal. The main finding was an increased number of periodic arousal fluctuations during non-REM sleep (measured as cyclic alternating pattern, CAP) during two consecutive nights (7-8 S.D. units above that observed in age-matched controls). Since CAP rate reflects the structural organization of non-REM sleep, this observation supports the hypothesis of a link between non-REM sleep and declarative memory performance.
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Affiliation(s)
- Luigi Ferini-Strambi
- Sleep Disorders Center, Scientific Institute H San Raffaele, University Vita-Salute San Raffaele, Via Stamina d'Ancona 20, 20127 Milano, Italy.
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Yu S, Liu N, Zeng T, Tian S, Chen N, Zhou Y, Ma Y. Age-related effects of bilateral frontal eye fields lesions on rapid eye movements during REM sleep in rhesus monkeys. Neurosci Lett 2004; 366:58-62. [PMID: 15265590 DOI: 10.1016/j.neulet.2004.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 04/07/2004] [Accepted: 05/08/2004] [Indexed: 11/25/2022]
Abstract
Rapid eye movement (REM) is one of the most characteristic features of REM sleep, but the mechanisms underlying its regulation remain unclear. The present study aims to investigate whether the frontal eye field (FEF) is involved in the regulation of the rapid eye movements during REM sleep. To address this question, we ablated the FEF in four rhesus monkeys and observed the effects of the lesions on sleep architecture. After lesions, two adult monkeys did not show any lesion effect. However, in the other two adolescent monkeys, both the total duration and percentage of the rapid eye movements during REM sleep were decreased moderately. The result suggests that the relation between the FEF and the regulation of the rapid eye movements during REM sleep may be affected by age factor, also indicating that both the functions of the FEF and the mechanisms underlying the control of rapid eye movements during REM sleep might not be the same throughout the whole life span of an animal.
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Affiliation(s)
- Shan Yu
- School of Life Sciences, University of Science and Technology of China, Hefei, PR China
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Wetzel W, Wagner T, Balschun D. REM sleep enhancement induced by different procedures improves memory retention in rats. Eur J Neurosci 2003; 18:2611-7. [PMID: 14622163 DOI: 10.1046/j.1460-9568.2003.02890.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Growing evidence supports the idea that sleep following learning is critically involved in memory formation. Recent studies suggest that information acquired during waking is reactivated and possibly consolidated during subsequent sleep, especially during rapid-eye movement (REM) or paradoxical sleep (PS). Critical reviews, however, have questioned PS and memory relationships, particularly because of shortcomings of the PS deprivation paradigm applied in many studies. Therefore, in the present study we used an opposite strategy, i.e. we investigated the effects of PS enhancement on memory retention. In three experiments, we found that selective PS enhancement, induced by different procedures after discrimination training in rats, results in increased retention tested 24 h later. Moreover, calculated in all animals (n = 61), there was a highly significant correlation between post-training PS values and retention scores. Our results suggest that an experimentally induced increase of PS after learning facilitates memory consolidation.
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Affiliation(s)
- Wolfram Wetzel
- Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany.
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37
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Landolt HP, Kelsoe JR, Rapaport MH, Gillin JC. Rapid tryptophan depletion reverses phenelzine-induced suppression of REM sleep. J Sleep Res 2003; 12:13-8. [PMID: 12603782 DOI: 10.1046/j.1365-2869.2003.00336.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Treatment with the monoamine oxidase inhibitor phenelzine completely suppressed rapid eye movement (REM) sleep in five depressed patients. Hypothesizing that increased serotonergic neurotransmission eliminated REM sleep, we administered a tryptophan-free amino acid drink (TFD) known to reduce plasma tryptophan and brain levels of serotonin. The TFD reversed the REM sleep suppression, while the control drink (TFD plus tryptophan) had virtually no effect on sleep. Neither TFD nor control drink affected mood, total sleep time, sleep efficiency or the all-night electroencephalogram power spectra in non-rapid eye movement (NREM) sleep. We report the first non-disruptive, double-blind method for studying human subjects overnight with and without REM sleep. It opens up a novel strategy for investigating the functions of REM sleep, and the roles of serotonin and REM sleep in the regulation of NREM sleep and mood.
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Affiliation(s)
- Hans-Peter Landolt
- Department of Psychiatry, University of California at San Diego, VA San Diego Healthcare System, San Diego, CA, USA.
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38
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Ruther E. Editorial zur Arbeit "Der Traum spricht - Eine archaische Sprache". Eine phanomenologische Studie von Klaus Kendel. SOMNOLOGIE 2003. [DOI: 10.1046/j.1439-054x.2003.02280.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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39
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Abstract
The hypothesis that sleep promotes learning and memory has long been a subject of active investigation. This hypothesis implies that sleep must facilitate synaptic plasticity in some way, and recent studies have provided evidence for such a function. Our knowledge of both the cellular neurophysiology of sleep states and of the cellular and molecular mechanisms underlying synaptic plasticity has expanded considerably in recent years. In this article, we review findings in these areas and discuss possible mechanisms whereby the neurophysiological processes characteristic of sleep states may serve to facilitate synaptic plasticity. We address this issue first on the cellular level, considering how activation of T-type Ca(2+) channels in nonREM sleep may promote either long-term depression or long-term potentiation, as well as how cellular events of REM sleep may influence these processes. We then consider how synchronization of neuronal activity in thalamocortical and hippocampal-neocortical networks in nonREM sleep and REM sleep could promote differential strengthening of synapses according to the degree to which activity in one neuron is synchronized with activity in other neurons in the network. Rather than advocating one specific cellular hypothesis, we have intentionally taken a broad approach, describing a range of possible mechanisms whereby sleep may facilitate synaptic plasticity on the cellular and/or network levels. We have also provided a general review of evidence for and against the hypothesis that sleep does indeed facilitate learning, memory, and synaptic plasticity.
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Affiliation(s)
- Joel H Benington
- Department of Biology, St. Bonaventure University, St. Bonaventure, NY 14778, USA
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40
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Kisley MA, Olincy A, Robbins E, Polk SD, Adler LE, Waldo MC, Freedman R. Sensory gating impairment associated with schizophrenia persists into REM sleep. Psychophysiology 2003; 40:29-38. [PMID: 12751801 DOI: 10.1111/1469-8986.00004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Physiological measures of sensory gating are increasingly used to study biological factors associated with attentional dysfunction in psychiatric and neurologic patient populations. The present study was designed to assess sensory gating during rapid eye movement (REM) sleep in patients with schizophrenia, a population bearing a genetic load for gating impairment. Auditory event-related potentials (ERPs) were recorded in response to paired clicks during separate waking and overnight sleep recording sessions in controls and schizophrenia patients. Suppression of ERP component P50 was significantly impaired in the patient group during both waking and REM sleep, whereas the difference between groups for N100 gating was dependent on state. These results suggest that REM sleep is an appropriate state during which to assess P50 gating in order to disentangle the effects of state and trait on sensory gating impairment in other clinical populations.
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Affiliation(s)
- Michael A Kisley
- Department of Psychiatry, University of Colorado Health Sciences Center and Denver Veteran's Affairs Medical Center, Denver, Colorado, USA.
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41
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Lee Kavanau J. REM and NREM sleep as natural accompaniments of the evolution of warm-bloodedness. Neurosci Biobehav Rev 2002; 26:889-906. [PMID: 12667495 DOI: 10.1016/s0149-7634(02)00088-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Divergence of primitive sleep into REM and NREM states is thought to have occurred in the nocturnal Triassic ancestors of mammals as a natural accompaniment of the evolution of warm-bloodedness. As ambient temperatures during twilight portions of primitive sleep traversed these evolving ancestors' core temperature, mechanisms of thermoregulatory control that employ muscle contractions became superfluous. The resulting loss of need for such contractions during twilight sleep led to muscle atonia. With muscle tone absent, selection favored the persistence of the fast waves of nocturnal activity during twilight sleep. Stimulations by these waves reinforce motor circuits at the increasing temperatures of evolving warm-bloodedness without leading to sleep-disturbing muscle contractions. By these and related interlinked adaptations, twilight sleep evolved into REM sleep. The daytime period of sleep became NREM sleep. The evolution of NREM and REM sleep following this scenario has implications for sleep's maintenance processes for long-term memories. During NREM sleep, there is an unsynchronized, uncoordinated stimulation and reinforcement of individual distributed component circuits of consolidated memories by slow wave potentials, a process termed 'uncoordinated reinforcement'. The corresponding process during REM sleep is the coordinated stimulation and reinforcement of these circuits by fast wave potentials. This action temporally binds the individual component circuit outputs into fully formed memories, a process termed 'coordinated reinforcement'. Sequential uncoordinated and coordinated reinforcement, that is, NREM followed by REM sleep, emerges as the most effective mechanism of long-term memory maintenance in vertebrates. With the evolution of this two-stage mechanism of long-term memory maintenance, it became adaptive to partition sleep into several NREM-REM cycles, thereby achieving a more lengthy application of the cooperative sequential actions.
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Affiliation(s)
- J Lee Kavanau
- Department of Organismic Biology, Ecology and Evolution, University of California at Los Angeles (UCLA), 4 90095-1606, USA.
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42
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Grözinger M, Beersma DGM, Fell J, Röschke J. Is the nonREM-REM sleep cycle reset by forced awakenings from REM sleep? Physiol Behav 2002; 77:341-7. [PMID: 12419411 DOI: 10.1016/s0031-9384(02)00862-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In selective REM sleep deprivation (SRSD), the occurrence of stage REM is repeatedly interrupted by short awakenings. Typically, the interventions aggregate in clusters resembling the REM episodes in undisturbed sleep. This salient phenomenon can easily be explained if the nonREM-REM sleep process is continued during the periods of forced wakefulness. However, earlier studies have alternatively suggested that awakenings from sleep might rather discontinue and reset the ultradian process. Theoretically, the two explanations predict a different distribution of REM episode duration. We evaluated 117 SRSD treatment nights recorded from 14 depressive inpatients receiving low dosages of Trimipramine. The alarms were triggered by an automatic mechanism for the detection of REM sleep and had to be canceled by the subjects themselves. The REM episodes were determined as in undisturbed sleep-they had to include the remaining REM activity and were separated by 30 min without REM epochs. The frequency histogram of REM episodes declined exponentially with episode duration for each of the first four sleep cycles. The duration of nonREM intervals revealed bimodal distributions. These results were found consistent with the model assuming a reset of the ultradian cycle upon awakening. Whether REM or nonREM activity is resumed on return to sleep can be modeled by a random decision whereby the probability for REM sleep might depend on the momentary REM pressure.
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Affiliation(s)
- Michael Grözinger
- Department of Psychiatry, University of Mainz, Untere Zahlbacher Str. 8, 55101 Mainz, Germany.
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43
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Karlsson KAE, Blumberg MS. The union of the state: myoclonic twitching is coupled with nuchal muscle atonia in infant rats. Behav Neurosci 2002; 116:912-7. [PMID: 12369810 DOI: 10.1037/0735-7044.116.5.912] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Active sleep (AS), as measured by the occurrence of myoclonic twitching (MT), is the most prevalent behavioral state in newborn rats. Historically, AS has been considered a developmental precursor of REM sleep, but recently this idea has been questioned. In the present study, the authors assess, in 2-, 5-, and 8-day-old rats, the relationship between MT and nuchal muscle atonia, a widely recognized component of REM sleep. At all ages, muscle atonia preceded MT and persisted until awake behaviors occurred. In addition, muscle tone decreased gradually during transitions from awake behavior to twitching. Thus, MT during infancy occurs against a backdrop of muscle atonia, a result that is consistent with the view that AS is a developmental precursor of REM sleep.
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44
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Werth E, Cote KA, Gallmann E, Borbély AA, Achermann P. Selective REM sleep deprivation during daytime I. Time course of interventions and recovery sleep. Am J Physiol Regul Integr Comp Physiol 2002; 283:R521-6. [PMID: 12121866 DOI: 10.1152/ajpregu.00462.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although repeated selective rapid eye movement (REM) sleep deprivation by awakenings during nighttime has shown that the number of sleep interruptions required to prevent REM sleep increases within and across consecutive nights, the underlying regulatory processes remained unspecified. To assess the role of circadian and homeostatic factors in REM sleep regulation, REM sleep was selectively deprived in healthy young adult males during a daytime sleep episode (7-15 h) after a night without sleep. Circadian REM sleep propensity is known to be high in the early morning. The number of interventions required to prevent REM sleep increased from the first to the third 2-h interval by a factor of two and then leveled off. Only a minor REM sleep rebound (11.6%) occurred in the following undisturbed recovery night. It is concluded that the limited rise of interventions during selective daytime REM sleep deprivation may be due to the declining circadian REM sleep propensity, which may partly offset the homeostatic drive and the sleep-dependent disinhibition of REM sleep.
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Affiliation(s)
- Esther Werth
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
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45
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Werth E, Achermann P, Borbély AA. Selective REM sleep deprivation during daytime. II. Muscle atonia in non-REM sleep. Am J Physiol Regul Integr Comp Physiol 2002; 283:R527-32. [PMID: 12121867 DOI: 10.1152/ajpregu.00466.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the hallmarks of rapid eye movement (REM) sleep is muscle atonia. Here we report extended epochs of muscle atonia in non-REM sleep (MAN). Their extent and time course was studied in a protocol that included a baseline night, a daytime sleep episode with or without selective REM sleep deprivation, and a recovery night. The distribution of the latency to the first occurrence of MAN was bimodal with a first mode shortly after sleep onset and a second mode 40 min later. Within a non-REM sleep episode, MAN showed a U-shaped distribution with the highest values before and after REM sleep. Whereas MAN was at a constant level over consecutive 2-h intervals of nighttime sleep, MAN showed high initial values when sleep began in the morning. Selective daytime REM sleep deprivation caused an initial enhancement of MAN during recovery sleep. It is concluded that episodes of MAN may represent an REM sleep equivalent and that it may be a marker of homeostatic and circadian REM sleep regulating processes. MAN episodes may contribute to the compensation of an REM sleep deficit.
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Affiliation(s)
- Esther Werth
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
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46
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Peigneux P, Laureys S, Delbeuck X, Maquet P. Sleeping brain, learning brain. The role of sleep for memory systems. Neuroreport 2001; 12:A111-24. [PMID: 11742260 DOI: 10.1097/00001756-200112210-00001] [Citation(s) in RCA: 221] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The hypothesis that sleep participates in the consolidation of recent memory traces has been investigated using four main paradigms: (1) effects of post-training sleep deprivation on memory consolidation, (2) effects of learning on post-training sleep, (3) effects of within sleep stimulation on the sleep pattern and on overnight memories, and (4) re-expression of behavior-specific neural patterns during post-training sleep. These studies convincingly support the idea that sleep is deeply involved in memory functions in humans and animals. However, the available data still remain too scarce to confirm or reject unequivocally the recently upheld hypothesis that consolidations of non-declarative and declarative memories are respectively dependent upon REM and NREM sleep processes.
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Affiliation(s)
- P Peigneux
- Cyclotron Research Center, University of Liège, Bât. B30, Sart Tilman, B-4000 Liège, Belgium
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47
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Abstract
It has been hypothesized that REM (rapid eye movement) sleep has an important role in memory consolidation. The evidence for this hypothesis is reviewed and found to be weak and contradictory. Animal studies correlating changes in REM sleep parameters with learning have produced inconsistent results and are confounded by stress effects. Humans with pharmacological and brain lesion-induced suppression of REM sleep do not show memory deficits, and other human sleep-learning studies have not produced consistent results. The time spent in REM sleep is not correlated with learning ability across humans, nor is there a positive relation between REM sleep time or intensity and encephalization across species. Although sleep is clearly important for optimum acquisition and performance of learned tasks, a major role in memory consolidation is unproven.
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Affiliation(s)
- J M Siegel
- Center for Sleep Research, Department of Veterans Affairs, Greater Los Angeles Healthcare System (VA GLAHCS), North Hills, CA 91343, USA.
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48
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Abstract
Converging evidence and new research methodologies from across the neurosciences permit the neuroscientific study of the role of sleep in off-line memory reprocessing, as well as the nature and function of dreaming. Evidence supports a role for sleep in the consolidation of an array of learning and memory tasks. In addition, new methodologies allow the experimental manipulation of dream content at sleep onset, permitting an objective and scientific study of this dream formation and a renewed search for the possible functions of dreaming and the biological processes subserving it.
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Affiliation(s)
- R Stickgold
- Laboratory of Neurophysiology and Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA.
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49
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Abstract
Sleep has been implicated in the plastic cerebral changes that underlie learning and memory. Indications that sleep participates in the consolidation of fresh memory traces come from a wide range of experimental observations. At the network level, reactivations during sleep of neuronal assemblies recently challenged by new environmental circumstances have been reported in different experimental designs. These neuronal assemblies are proposed to be involved in the processing of memory traces during sleep. However, despite this rapidly growing body of experimental data, evidence for the influence of sleep discharge patterns on memory traces remains fragmentary. The underlying role of sleep in learning and memory has yet to be precisely characterized.
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Affiliation(s)
- P Maquet
- Wellcome Department of Cognitive Neurology, University College London, London WC1N 3BG, UK
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