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Koller DP, Kasanin V, Flynn-Evans EE, Sullivan JP, Dijk DJ, Czeisler CA, Barger LK. Altered sleep spindles and slow waves during space shuttle missions. NPJ Microgravity 2021; 7:48. [PMID: 34795291 PMCID: PMC8602337 DOI: 10.1038/s41526-021-00177-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 10/07/2021] [Indexed: 11/09/2022] Open
Abstract
Sleep deficiencies and associated performance decrements are common among astronauts during spaceflight missions. Previously, sleep in space was analyzed with a focus on global measures while the intricate structure of sleep oscillations remains largely unexplored. This study extends previous findings by analyzing how spaceflight affects characteristics of sleep spindles and slow waves, two sleep oscillations associated with sleep quality and quantity, in four astronauts before, during and after two Space Shuttle missions. Analysis of these oscillations revealed significantly increased fast spindle density, elevated slow spindle frequency, and decreased slow wave amplitude in space compared to on Earth. These results reflect sleep characteristics during spaceflight on a finer electrophysiological scale and provide an opportunity for further research on sleep in space.
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Affiliation(s)
- Dominik P Koller
- Advanced Concepts Team, European Space Agency, ESTEC, Noordwijk, The Netherlands.
| | - Vida Kasanin
- Advanced Concepts Team, European Space Agency, ESTEC, Noordwijk, The Netherlands
| | - Erin E Flynn-Evans
- Fatigue Countermeasures Laboratory, Human Systems Integration Division, Exploration Technology Directorate, NASA Ames Research Center, Moffett Field, CA, USA
| | - Jason P Sullivan
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, Guildford, UK
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Laura K Barger
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
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2
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Jiang D, Ma Y, Wang Y. A robust two-stage sleep spindle detection approach using single-channel EEG. J Neural Eng 2021; 18. [PMID: 33326950 DOI: 10.1088/1741-2552/abd463] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/16/2020] [Indexed: 11/12/2022]
Abstract
Objective.Sleep spindles in the electroencephalogram (EEG) are significant in sleep analysis related to cognitive functions and neurological diseases, and thus are of great clinical interests. An automatic sleep spindle detection algorithm could help decrease the workload of visual inspection by sleep clinicians.Approach.We propose a robust two-stage approach for sleep spindle detection using single-channel EEG. In the pre-detection stage, a stable number of sleep spindle candidates are discovered using the Teager energy operator with adaptive parameters, where the number of true sleep spindles are ensured as many as possible to maximize the detection sensitivity. In the refinement stage, representative features are designed and a bagging classifier is exploited to further recognize the true spindles from all candidates, in order to remove the false detection in the first stage.Main results.Using the union of all experts' annotations as the ground truth, its performance outperforms state-of-the-art works in terms of F1-score (F1) on two public databases (F1: 0.814 for Montreal archive of sleep studies dataset and 0.690 for DREAMS dataset). The annotation consistency between the proposed method and certain selected expert as the trainer could exceed the consistency between two human experts.Significance.The proposed sleep spindle detection method is based on single-channel EEG thus introduces as less interference to the subjects as possible. It is robust to subject variations between databases and is capable of learning certain annotation rules, which is expected to help facilitate the manual labeling of certain experts. In addition, this method is fast enough for real-time applications.
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Affiliation(s)
- Dihong Jiang
- Department of Electronic Engineering, Fudan University, Shanghai, People's Republic of China
| | - Yu Ma
- Department of Electronic Engineering, Fudan University, Shanghai, People's Republic of China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai, People's Republic of China
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai, People's Republic of China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai, People's Republic of China
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3
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Pesonen AK, Merikanto I, Halonen R, Ujma P, Makkonen T, Räikkönen K, Lahti J, Kuula L. Polygenic impact of morningness on the overnight dynamics of sleep spindle amplitude. GENES BRAIN AND BEHAVIOR 2020; 19:e12641. [PMID: 31925898 DOI: 10.1111/gbb.12641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 12/18/2019] [Accepted: 01/07/2020] [Indexed: 11/28/2022]
Abstract
Sleep spindles are thalamocortical oscillations that contribute to sleep maintenance and sleep-related brain plasticity. The current study is an explorative study of the circadian dynamics of sleep spindles in relation to a polygenic score (PGS) for circadian preference towards morningness. The participants represent the 17-year follow-up of a birth cohort having both genome-wide data and an ambulatory sleep electroencephalography measurement available ( N = 154, Mean age = 16.9, SD = 0.1 years, 57% girls). Based on a recent genome-wide association study, we calculated a PGS for circadian preference towards morningness across the whole genome, including 354 single-nucleotide polymorphisms. Stage 2 slow (9-12.5 Hz, N = 186 739) and fast (12.5-16 Hz, N = 135 504) sleep spindles were detected using an automated algorithm with individual time tags and amplitudes for each spindle. There was a significant interaction of PGS for morningness and timing of sleep spindles across the night. These growth curve models showed a curvilinear trajectory of spindle amplitudes: those with a higher PGS for morningness showed higher slow spindle amplitudes in frontal derivations, and a faster dissipation of spindle amplitude in central derivations. Overall, the findings provide new evidence on how individual sleep spindle trajectories are influenced by genetic factors associated with circadian type. The finding may lead to new hypotheses on the associations previously observed between circadian types, psychiatric problems and spindle activity.
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Affiliation(s)
- Anu-Katriina Pesonen
- SleepWell Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ilona Merikanto
- SleepWell Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,National Institute for Health and Welfare, Helsinki, Finland
| | - Risto Halonen
- SleepWell Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Peter Ujma
- Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary.,Epilepsy Centre, National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Tommi Makkonen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Katri Räikkönen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jari Lahti
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Liisa Kuula
- SleepWell Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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4
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Mylonas D, Tocci C, Coon WG, Baran B, Kohnke EJ, Zhu L, Vangel MG, Stickgold R, Manoach DS. Naps reliably estimate nocturnal sleep spindle density in health and schizophrenia. J Sleep Res 2019; 29:e12968. [PMID: 31860157 DOI: 10.1111/jsr.12968] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 11/21/2019] [Accepted: 11/23/2019] [Indexed: 01/10/2023]
Abstract
Sleep spindles, defining oscillations of non-rapid eye movement stage 2 sleep (N2), mediate memory consolidation. Spindle density (spindles/minute) is a stable, heritable feature of the sleep electroencephalogram. In schizophrenia, reduced spindle density correlates with impaired sleep-dependent memory consolidation and is a promising treatment target. Measuring sleep spindles is also important for basic studies of memory. However, overnight sleep studies are expensive, time consuming and require considerable infrastructure. Here we investigated whether afternoon naps can reliably and accurately estimate nocturnal spindle density in health and schizophrenia. Fourteen schizophrenia patients and eight healthy controls had polysomnography during two overnights and three afternoon naps. Although spindle density was lower during naps than nights, the two measures were highly correlated. For both groups, naps and nights provided highly reliable estimates of spindle density. We conclude that naps provide an accurate, reliable and more scalable alternative to measuring spindle density overnight.
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Affiliation(s)
- Dimitrios Mylonas
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Catherine Tocci
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA
| | - William G Coon
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Bengi Baran
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Erin J Kohnke
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA
| | - Lin Zhu
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA
| | - Mark G Vangel
- Department of Radiology, Massachussets General Hospital, Charlestown, MA, USA.,Department of Biostatistics, Harvard Medical School, Boston, MA, USA
| | - Robert Stickgold
- Harvard Medical School, Boston, MA, USA.,Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Dara S Manoach
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
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5
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Abstract
Sleep spindles are burstlike signals in the electroencephalogram (EEG) of the sleeping mammalian brain and electrical surface correlates of neuronal oscillations in thalamus. As one of the most inheritable sleep EEG signatures, sleep spindles probably reflect the strength and malleability of thalamocortical circuits that underlie individual cognitive profiles. We review the characteristics, organization, regulation, and origins of sleep spindles and their implication in non-rapid-eye-movement sleep (NREMS) and its functions, focusing on human and rodent. Spatially, sleep spindle-related neuronal activity appears on scales ranging from small thalamic circuits to functional cortical areas, and generates a cortical state favoring intracortical plasticity while limiting cortical output. Temporally, sleep spindles are discrete events, part of a continuous power band, and elements grouped on an infraslow time scale over which NREMS alternates between continuity and fragility. We synthesize diverse and seemingly unlinked functions of sleep spindles for sleep architecture, sensory processing, synaptic plasticity, memory formation, and cognitive abilities into a unifying sleep spindle concept, according to which sleep spindles 1) generate neural conditions of large-scale functional connectivity and plasticity that outlast their appearance as discrete EEG events, 2) appear preferentially in thalamic circuits engaged in learning and attention-based experience during wakefulness, and 3) enable a selective reactivation and routing of wake-instated neuronal traces between brain areas such as hippocampus and cortex. Their fine spatiotemporal organization reflects NREMS as a physiological state coordinated over brain and body and may indicate, if not anticipate and ultimately differentiate, pathologies in sleep and neurodevelopmental, -degenerative, and -psychiatric conditions.
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Affiliation(s)
- Laura M J Fernandez
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Anita Lüthi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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6
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Fang Z, Ray LB, Houldin E, Smith D, Owen AM, Fogel SM. Sleep Spindle-dependent Functional Connectivity Correlates with Cognitive Abilities. J Cogn Neurosci 2019; 32:446-466. [PMID: 31659927 DOI: 10.1162/jocn_a_01488] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
EEG studies have shown that interindividual differences in the electrophysiological properties of sleep spindles (e.g., density, amplitude, duration) are highly correlated with trait-like "reasoning" abilities (i.e., "fluid intelligence"; problem-solving skills; the ability to employ logic or identify complex patterns), but not interindividual differences in STM or "verbal" intellectual abilities. Previous simultaneous EEG-fMRI studies revealed brain activations time-locked to spindles. Our group has recently demonstrated that the extent of activation in a subset of these regions was related to interindividual differences in reasoning intellectual abilities, specifically. However, spindles reflect communication between spatially distant and functionally distinct brain areas. The functional communication among brain regions related to spindles and their relationship to reasoning abilities have yet to be investigated. Using simultaneous EEG-fMRI sleep recordings and psychophysiological interaction analysis, we identified spindle-related functional communication among brain regions in the thalamo-cortical-BG system, the salience network, and the default mode network. Furthermore, the extent of the functional connectivity of the cortical-striatal circuitry and the thalamo-cortical circuitry was specifically related to reasoning abilities but was unrelated to STM or verbal abilities, thus suggesting that individuals with higher fluid intelligence have stronger functional coupling among these brain areas during spontaneous spindle events. This may serve as a first step in further understanding the function of sleep spindles and the brain network functional communication, which support the capacity for fluid intelligence.
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Affiliation(s)
- Zhuo Fang
- Brain & Mind Institute, Western University, London, Canada.,University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
| | - Laura B Ray
- Brain & Mind Institute, Western University, London, Canada.,Sleep Unit, the Royal's Institute for Mental Health Research, University of Ottawa, Ottawa, Canada
| | - Evan Houldin
- Brain & Mind Institute, Western University, London, Canada.,Western University, London, Canada
| | - Dylan Smith
- University of Ottawa, Ottawa, Canada.,Sleep Unit, the Royal's Institute for Mental Health Research, University of Ottawa, Ottawa, Canada
| | - Adrian M Owen
- Brain & Mind Institute, Western University, London, Canada.,Western University, London, Canada
| | - Stuart M Fogel
- Brain & Mind Institute, Western University, London, Canada.,Western University, London, Canada.,University of Ottawa, Ottawa, Canada.,Sleep Unit, the Royal's Institute for Mental Health Research, University of Ottawa, Ottawa, Canada.,University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
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7
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Adamantidis AR, Gutierrez Herrera C, Gent TC. Oscillating circuitries in the sleeping brain. Nat Rev Neurosci 2019; 20:746-762. [DOI: 10.1038/s41583-019-0223-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2019] [Indexed: 12/20/2022]
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8
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Form and Function of Sleep Spindles across the Lifespan. Neural Plast 2016; 2016:6936381. [PMID: 27190654 PMCID: PMC4848449 DOI: 10.1155/2016/6936381] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/16/2016] [Indexed: 01/11/2023] Open
Abstract
Since the advent of EEG recordings, sleep spindles have been identified as hallmarks of non-REM sleep. Despite a broad general understanding of mechanisms of spindle generation gleaned from animal studies, the mechanisms underlying certain features of spindles in the human brain, such as “global” versus “local” spindles, are largely unknown. Neither the topography nor the morphology of sleep spindles remains constant throughout the lifespan. It is likely that changes in spindle phenomenology during development and aging are the result of dramatic changes in brain structure and function. Across various developmental windows, spindle activity is correlated with general cognitive aptitude, learning, and memory; however, these correlations vary in strength, and even direction, depending on age and metrics used. Understanding these differences across the lifespan should further clarify how these oscillations are generated and their function under a variety of circumstances. We discuss these issues, and their translational implications for human cognitive function. Because sleep spindles are similarly affected in disorders of neurodevelopment (such as schizophrenia) and during aging (such as neurodegenerative conditions), both types of disorders may benefit from therapies based on a better understanding of spindle function.
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9
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Sleep-Wake Regulation and Its Impact on Working Memory Performance: The Role of Adenosine. BIOLOGY 2016; 5:biology5010011. [PMID: 26861410 PMCID: PMC4810168 DOI: 10.3390/biology5010011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 11/28/2022]
Abstract
The sleep-wake cycle is regulated by a fine-tuned interplay between sleep-homeostatic and circadian mechanisms. Compelling evidence suggests that adenosine plays an important role in mediating the increase of homeostatic sleep pressure during time spent awake and its decrease during sleep. Here, we summarize evidence that adenosinergic mechanisms regulate not only the dynamic of sleep pressure, but are also implicated in the interaction of homeostatic and circadian processes. We review how this interaction becomes evident at several levels, including electrophysiological data, neuroimaging studies and behavioral observations. Regarding complex human behavior, we particularly focus on sleep-wake regulatory influences on working memory performance and underlying brain activity, with a specific emphasis on the role of adenosine in this interplay. We conclude that a change in adenosinergic mechanisms, whether exogenous or endogenous, does not only impact on sleep-homeostatic processes, but also interferes with the circadian timing system.
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10
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Ujma PP, Bódizs R, Gombos F, Stintzing J, Konrad BN, Genzel L, Steiger A, Dresler M. Nap sleep spindle correlates of intelligence. Sci Rep 2015; 5:17159. [PMID: 26607963 PMCID: PMC4660428 DOI: 10.1038/srep17159] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/26/2015] [Indexed: 11/09/2022] Open
Abstract
Sleep spindles are thalamocortical oscillations in non-rapid eye movement (NREM) sleep, that play an important role in sleep-related neuroplasticity and offline information processing. Several studies with full-night sleep recordings have reported a positive association between sleep spindles and fluid intelligence scores, however more recently it has been shown that only few sleep spindle measures correlate with intelligence in females, and none in males. Sleep spindle regulation underlies a circadian rhythm, however the association between spindles and intelligence has not been investigated in daytime nap sleep so far. In a sample of 86 healthy male human subjects, we investigated the correlation between fluid intelligence and sleep spindle parameters in an afternoon nap of 100 minutes. Mean sleep spindle length, amplitude and density were computed for each subject and for each derivation for both slow and fast spindles. A positive association was found between intelligence and slow spindle duration, but not any other sleep spindle parameter. As a positive correlation between intelligence and slow sleep spindle duration in full-night polysomnography has only been reported in females but not males, our results suggest that the association between intelligence and sleep spindles is more complex than previously assumed.
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Affiliation(s)
- Péter P Ujma
- Institute of Behavioural Sciences, Semmelweis University, H-1089 Budapest, Hungary.,National Institute of Clinical Neuroscience, Epilepsy Centrum, Department of Neurology, H-1145 Budapest, Hungary
| | - Róbert Bódizs
- Institute of Behavioural Sciences, Semmelweis University, H-1089 Budapest, Hungary.,Department of General Psychology, Pázmány Péter Catholic University, H-1088 Budapest, Hungary
| | - Ferenc Gombos
- Department of General Psychology, Pázmány Péter Catholic University, H-1088 Budapest, Hungary
| | | | - Boris N Konrad
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6525 EN Nijmegen, The Netherlands
| | - Lisa Genzel
- Centre for Cognitive and Neural Systems, University of Edinburgh, EH8 9JZ Edinburgh, UK
| | - Axel Steiger
- Max Planck Institute of Psychiatry, 80804 Munich, Germany
| | - Martin Dresler
- Max Planck Institute of Psychiatry, 80804 Munich, Germany.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6525 EN Nijmegen, The Netherlands
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11
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Rosinvil T, Lafortune M, Sekerovic Z, Bouchard M, Dubé J, Latulipe-Loiselle A, Martin N, Lina JM, Carrier J. Age-related changes in sleep spindles characteristics during daytime recovery following a 25-hour sleep deprivation. Front Hum Neurosci 2015; 9:323. [PMID: 26089788 PMCID: PMC4452883 DOI: 10.3389/fnhum.2015.00323] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 05/19/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The mechanisms underlying sleep spindles (~11-15 Hz; >0.5 s) help to protect sleep. With age, it becomes increasingly difficult to maintain sleep at a challenging time (e.g., daytime), even after sleep loss. This study compared spindle characteristics during daytime recovery and nocturnal sleep in young and middle-aged adults. In addition, we explored whether spindles characteristics in baseline nocturnal sleep were associated with the ability to maintain sleep during daytime recovery periods in both age groups. METHODS Twenty-nine young (15 women and 14 men; 27.3 y ± 5.0) and 31 middle-aged (19 women and 13 men; 51.6 y ± 5.1) healthy subjects participated in a baseline nocturnal sleep and a daytime recovery sleep after 25 hours of sleep deprivation. Spindles were detected on artifact-free Non-rapid eye movement (NREM) sleep epochs. Spindle density (nb/min), amplitude (μV), frequency (Hz), and duration (s) were analyzed on parasagittal (linked-ears) derivations. RESULTS In young subjects, spindle frequency increased during daytime recovery sleep as compared to baseline nocturnal sleep in all derivations, whereas middle-aged subjects showed spindle frequency enhancement only in the prefrontal derivation. No other significant interaction between age group and sleep condition was observed. Spindle density for all derivations and centro-occipital spindle amplitude decreased whereas prefrontal spindle amplitude increased from baseline to daytime recovery sleep in both age groups. Finally, no significant correlation was found between spindle characteristics during baseline nocturnal sleep and the marked reduction in sleep efficiency during daytime recovery sleep in both young and middle-aged subjects. CONCLUSION These results suggest that the interaction between homeostatic and circadian pressure modulates spindle frequency differently in aging. Spindle characteristics do not seem to be linked with the ability to maintain daytime recovery sleep.
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Affiliation(s)
- T. Rosinvil
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | - M. Lafortune
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | - Z. Sekerovic
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | - M. Bouchard
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | - J. Dubé
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | | | - N. Martin
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
| | - J. M. Lina
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Electrical Engineering, École de Technologie SupérieureMontréal, QC, Canada
| | - J. Carrier
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de MontréalMontréal, QC, Canada
- Department of Psychology, Université de MontréalMontréal, QC, Canada
- Research Center, Institut Universitaire Gériatrique de MontréalMontréal, QC, Canada
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12
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A two-night comparison in the sleep laboratory as a tool to challenge the relationship between sleep initiation, cardiophysiological and thermoregulatory changes in women with difficulties initiating sleep and thermal discomfort. Physiol Behav 2013; 114-115:77-82. [DOI: 10.1016/j.physbeh.2013.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/25/2012] [Accepted: 02/26/2013] [Indexed: 12/18/2022]
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13
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Nonclercq A, Urbain C, Verheulpen D, Decaestecker C, Van Bogaert P, Peigneux P. Sleep spindle detection through amplitude–frequency normal modelling. J Neurosci Methods 2013; 214:192-203. [DOI: 10.1016/j.jneumeth.2013.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 10/27/2022]
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14
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Frey S, Birchler-Pedross A, Hofstetter M, Brunner P, Götz T, Münch M, Blatter K, Knoblauch V, Wirz-Justice, A, Cajochen C. Young Women With Major Depression Live on Higher Homeostatic Sleep Pressure Than Healthy Controls. Chronobiol Int 2012; 29:278-94. [DOI: 10.3109/07420528.2012.656163] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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15
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Morris CJ, Aeschbach D, Scheer FAJL. Circadian system, sleep and endocrinology. Mol Cell Endocrinol 2012; 349:91-104. [PMID: 21939733 PMCID: PMC3242827 DOI: 10.1016/j.mce.2011.09.003] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 08/19/2011] [Accepted: 09/01/2011] [Indexed: 11/23/2022]
Abstract
Levels of numerous hormones vary across the day and night. Such fluctuations are not only attributable to changes in sleep/wakefulness and other behaviors but also to a circadian timing system governed by the suprachiasmatic nucleus of the hypothalamus. Sleep has a strong effect on levels of some hormones such as growth hormone but little effect on others which are more strongly regulated by the circadian timing system (e.g., melatonin). Whereas the exact mechanisms through which sleep affects circulating hormonal levels are poorly understood, more is known about how the circadian timing system influences the secretion of hormones. The suprachiasmatic nucleus exerts its influence on hormones via neuronal and humoral signals but it is now also apparent that peripheral tissues contain circadian clock proteins, similar to those in the suprachiasmatic nucleus, that are also involved in hormone regulation. Under normal circumstances, behaviors and the circadian timing system are synchronized with an optimal phase relationship and consequently hormonal systems are exquisitely regulated. However, many individuals (e.g., shift-workers) frequently and/or chronically undergo circadian misalignment by desynchronizing their sleep/wake and fasting/feeding cycle from the circadian timing system. Recent experiments indicate that circadian misalignment has an adverse effect on metabolic and hormonal factors such as circulating glucose and insulin. Further research is needed to determine the underlying mechanisms that cause the negative effects induced by circadian misalignment. Such research could aid the development of novel countermeasures for circadian misalignment.
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Affiliation(s)
- Christopher J Morris
- Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA, United States.
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Yasenkov R, Deboer T. Circadian regulation of sleep and the sleep EEG under constant sleep pressure in the rat. Sleep 2010; 33:631-41. [PMID: 20469805 DOI: 10.1093/sleep/33.5.631] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVE Sleep is regulated by homeostatic and circadian processes. Slow wave activity (SWA; 1-4 Hz) in the NREM sleep electroencephalogram (EEG) reflects sleep homeostasis. Activity of faster EEG frequencies (10-25 Hz) is thought to be under influence of circadian factors. The relative contribution of both processes to the distribution of sleep and wakefulness and EEG activity in rodents remains uncertain. DESIGN Continuous EEG recording in rats in constant dark conditions (DD) were performed and a sleep deprivation protocol consisting of 2 h sleep deprivation followed by 2 h of rest (2h/2h) was applied for 48 h to obtain a constant sleep pressure. SETTINGS Basic sleep research laboratory. PATIENTS OR PARTICIPANTS Adult male Wistar rats. INTERVENTION Sleep deprivation. MEASUREMENTS AND RESULTS Under the 2h/2h protocol, the circadian modulation of waking, NREM and REM sleep was markedly reduced compared to the baseline, affecting the frequency of vigilance state episodes and the duration of REM sleep and waking episodes. In contrast, NREM sleep episode duration still showed a daily modulation. Consecutive 2h values of SWA in NREM sleep were stabile during the 2h\2h protocol, while NREM sleep EEG activity within the higher frequencies (7-25 Hz) still demonstrated strong circadian modulation, which did not differ from baseline. CONCLUSIONS In rats, the daily modulation of REM sleep is less pronounced compared to NREM sleep and waking. In contrast to SWA, activity in higher frequencies (7-25 Hz) in the NREM sleep EEG have an endogenous circadian origin and are not influenced by sleep homeostatic mechanisms.
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Affiliation(s)
- Roman Yasenkov
- Laboratory for Neurophysiology, Department of Molecular Cell Biology Leiden University Medical Center, Leiden, The Netherlands
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17
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Aeschbach D, Lockyer BJ, Dijk DJ, Lockley SW, Nuwayser ES, Nichols LD, Czeisler CA. Use of transdermal melatonin delivery to improve sleep maintenance during daytime. Clin Pharmacol Ther 2009; 86:378-82. [PMID: 19606092 PMCID: PMC2909186 DOI: 10.1038/clpt.2009.109] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oral melatonin (MEL) can improve daytime sleep, but the hormone's short elimination half-life limits its use as a hypnotic in shift workers and individuals with jet lag or other sleep problems. Here we show, in healthy subjects, that transdermal delivery of MEL during the daytime can elevate plasma MEL and reduce waking after sleep onset, by promoting sleep in the latter part of an 8-h sleep opportunity. Transdermal MEL may have advantages over fast-release oral MEL in improving sleep maintenance during adverse circadian phases.
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Affiliation(s)
- D Aeschbach
- Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
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18
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Birchler-Pedross A, Schröder CM, Münch M, Knoblauch V, Blatter K, Schnitzler-Sack C, Wirz-Justice A, Cajochen C. Subjective well-being is modulated by circadian phase, sleep pressure, age, and gender. J Biol Rhythms 2009; 24:232-42. [PMID: 19465700 DOI: 10.1177/0748730409335546] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Subjective well-being largely depends on mood, which shows circadian rhythmicity and can be linked to rhythms in many physiological circadian markers, such as melatonin and cortisol. In healthy young volunteers mood is influenced by an interaction of circadian phase and the duration of time awake. The authors analyzed this interaction under differential sleep pressure conditions to investigate age and gender effects on subjective well-being. Sixteen healthy young (8 women, 8 men; 20-35 years) and 16 older volunteers (8 women, 8 men; 55-75 years) underwent a 40-h sleep deprivation (high sleep pressure) and a 40-h nap protocol (low sleep pressure) in a balanced crossover design under constant routine conditions. Mood, tension, and physical comfort were assessed by visual analogue scales during scheduled wakefulness, and their average formed a composite score of well-being. Significant variations in well-being were determined by the factors "age," "sleep pressure," and "circadian phase." Well-being was generally worse under high than low sleep pressure. Older volunteers felt significantly worse than the young under both experimental conditions. Significant interactions were found between "sleep pressure" and "age," and between "sleep pressure" and "gender." This indicated that older volunteers and women responded with a greater impairment in well-being under high compared with low sleep pressure. The time course of well-being displayed a significant circadian modulation, particularly in women under high sleep pressure conditions. The results demonstrate age- and/or gender-related modifications of well-being related to sleep deprivation and circadian phase and thus point to specific biological components of mood vulnerability.
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19
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Dijk DJ, Archer SN. Circadian and Homeostatic Regulation of Human Sleep and Cognitive Performance and Its Modulation by PERIOD3. Sleep Med Clin 2009; 4:111-125. [PMID: 33162871 DOI: 10.1016/j.jsmc.2009.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XP, UK
| | - Simon N Archer
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XP, UK
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20
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Cajochen C, Di Biase R, Imai M. Interhemispheric EEG asymmetries during unilateral bright-light exposure and subsequent sleep in humans. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1053-60. [PMID: 18216135 DOI: 10.1152/ajpregu.00747.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested whether evening exposure to unilateral photic stimulation has repercussions on interhemispheric EEG asymmetries during wakefulness and later sleep. Because light exerts an alerting response in humans, which correlates with a decrease in waking EEG theta/alpha-activity and a reduction in sleep EEG delta activity, we hypothesized that EEG activity in these frequency bands show interhemispheric asymmetries after unilateral bright light (1,500 lux) exposure. A 2-h hemi-field light exposure acutely suppressed occipital EEG alpha activity in the ipsilateral hemisphere activated by light. Subjects felt more alert during bright light than dim light, an effect that was significantly more pronounced during activation of the right than the left visual cortex. During subsequent sleep, occipital EEG activity in the delta and theta range was significantly reduced after activation of the right visual cortex but not after stimulation of the left visual cortex. Furthermore, hemivisual field light exposure was able to shift the left predominance in occipital spindle EEG activity toward the stimulated hemisphere. Time course analysis revealed that this spindle shift remained significant during the first two sleep cycles. Our results reflect rather a hemispheric asymmetry in the alerting action of light than a use-dependent recovery function of sleep in response to the visual stimulation during prior waking. However, the observed shift in the spindle hemispheric dominance in the occipital cortex may still represent subtle local use-dependent recovery functions during sleep in a frequency range different from the delta range.
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Affiliation(s)
- Christian Cajochen
- Centre for Chronobiology, Psychiatric University Clinics, Wilhelm Kleinstr. 27, CH-4025 Basel, Switzerland.
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21
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Münch MY, Cain SW, Duffy JF. Biological Rhythms Workshop IC: sleep and rhythms. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 72:35-46. [PMID: 18419261 DOI: 10.1101/sqb.2007.72.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Rhythms of sleep and wakefulness (typically measured as rest/activity rhythms) are among the most prominent of biological rhythms and therefore were among the first to be recorded in early chronobiological studies. These rhythms can provide useful information about the central biological clock, although an appreciation of the problems associated with using rest/activity to infer central clock function is important in the design and interpretation of chronobiological experiments in both animals and humans. Here, we review the anatomical and neurophysiologic bases of sleep regulation in mammals as well as similarities and differences between the sleep of humans and that of other organisms. We outline how human sleep is measured, the role of the circadian system in models of human sleep regulation, and human circadian rhythm sleep disorders. Although the function of sleep is still not completely understood, sleep has a critical role for human health, and we have attempted to outline the role that the circadian timing system has in regulating human sleep and in contributing to sleep disorders.
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Affiliation(s)
- M Y Münch
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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22
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Schmidt C, Peigneux P, Muto V, Schenkel M, Knoblauch V, Münch M, de Quervain DJF, Wirz-Justice A, Cajochen C. Encoding difficulty promotes postlearning changes in sleep spindle activity during napping. J Neurosci 2006; 26:8976-82. [PMID: 16943553 PMCID: PMC6675334 DOI: 10.1523/jneurosci.2464-06.2006] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Learning-dependent increases in sleep spindle density have been reported during nocturnal sleep immediately after the learning session. Here, we investigated experience-dependent changes in daytime sleep EEG activity after declarative learning of unrelated word pairs. At weekly intervals, 13 young male volunteers spent three 24 h sessions in the laboratory under carefully controlled homeostatic and circadian conditions. At approximately midday, subjects performed either one of two word-pair learning tasks or a matched nonlearning control task, in a counterbalanced order. The two learning lists differed in the level of concreteness of the words used, resulting in an easier and a more difficult associative encoding condition, as confirmed by performance at immediate cued recall. Subjects were then allowed to sleep for 4 h; afterward, delayed cued recall was tested. Compared with the control condition, sleep EEG spectral activity in the low spindle frequency range and the density of low-frequency sleep spindles (11.25-13.75 Hz) were both significantly increased in the left frontal cortex after the difficult but not after the easy encoding condition. Furthermore, we found positive correlations between these EEG changes during sleep and changes in memory performance between pre-nap and post-nap recall sessions. These results indicate that, like during nocturnal sleep, daytime sleep EEG oscillations including spindle activity are modified after declarative learning of word pairs. Furthermore, we demonstrate here that the nature of the learning material is a determinant factor for sleep-related alterations after declarative learning.
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Affiliation(s)
- Christina Schmidt
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
- Cyclotron Research Centre and
- Department of Cognitive Psychology, University of Liège, B-4000 Liège, Belgium
| | | | - Vincenzo Muto
- Department of Psychology, II University of Naples, 81100 Caserta, Italy, and
| | - Maja Schenkel
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
| | - Vera Knoblauch
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
| | - Mirjam Münch
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
| | | | - Anna Wirz-Justice
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric University Clinics, CH-4025 Basel, Switzerland
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23
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Berner I, Schabus M, Wienerroither T, Klimesch W. The significance of sigma neurofeedback training on sleep spindles and aspects of declarative memory. Appl Psychophysiol Biofeedback 2006; 31:97-114. [PMID: 16845599 PMCID: PMC3000596 DOI: 10.1007/s10484-006-9013-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2005] [Accepted: 06/14/2006] [Indexed: 10/24/2022]
Abstract
The functional significance of sleep spindles for overnight memory consolidation and general learning aptitude as well as the effect of four 10-minute sessions of spindle frequency (11.6-16 Hz, sigma) neurofeedback-training on subsequent sleep spindle activity and overnight performance change was investigated. Before sleep, subjects were trained on a paired-associate word list task after having received either neurofeedback training (NFT) or pseudofeedback training (PFT). Although NFT had no significant impact on subsequent spindle activity and behavioral outcomes, there was a trend for enhanced sigma band-power during NREM (stage 2 to 4) sleep after NFT as compared to PFT. Furthermore, a significant positive correlation between spindle activity during slow wave sleep (in the first night half) and overall memory performance was revealed. The results support the view that the considerable inter-individual variance in sleep spindle activity can at least be partly explained by differences in the ability to acquire new declarative information. We conclude that the short NFT before sleep was not sufficient to efficiently enhance phasic spindle activity and/or to influence memory processing. NFT was, however, successful in increasing sigma power, presumably because sigma NFT effects become more easily evident in actually trained frequency bands than in associated phasic spindle activity.
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Affiliation(s)
- I. Berner
- University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Address all University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria;
| | - M. Schabus
- University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria
- Address all University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria;
| | - T. Wienerroither
- University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria
| | - W. Klimesch
- University of Salzburg, Division of Physiological Psychology, Hellbrunnerstr. 34, 5020 Salzburg, Austria
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24
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Kräuchi K, Knoblauch V, Wirz-Justice A, Cajochen C. Challenging the sleep homeostat does not influence the thermoregulatory system in men: evidence from a nap vs. sleep-deprivation study. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1052-61. [PMID: 16306164 DOI: 10.1152/ajpregu.00381.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of our study was to understand the relationship between the components of the three-process model of sleepiness regulation (homeostatic, circadian, and sleep inertia) and the thermoregulatory system. This was achieved by comparing the impact of a 40-h sleep deprivation vs. a 40-h multiple nap paradigm (10 cycles with 150/75 min wakefulness/sleep episodes) on distal and proximal skin temperatures, core body temperature (CBT), melatonin secretion, subjective sleepiness, and nocturnal sleep EEG slow-wave activity in eight healthy young men in a “controlled posture” protocol. The main finding of the study was that accumulation of sleep pressure increased subjective sleepiness and slow-wave activity during the succeeding recovery night but did not influence the thermoregulatory system as measured by distal, proximal, and CBT. The circadian rhythm of sleepiness (and proximal temperature) was significantly correlated and phase locked with CBT, whereas distal temperature and melatonin secretion were phase advanced (by 113 ± 28 and 130 ± 30 min, respectively; both P < 0.005). This provides evidence for a primary role of distal vasodilatation in the circadian regulation of CBT and its relationship with sleepiness. Specific thermoregulatory changes occur at lights off and on. After lights off, skin temperatures increased and were most pronounced for distal; after lights on, the converse occurred. The decay in distal temperature (vasoconstriction) was significantly correlated with the disappearance of sleep inertia. These effects showed minor and nonsignificant circadian modulation. In summary, the thermoregulatory system seems to be independent of the sleep homeostat, but the circadian modulation of sleepiness and sleep inertia is clearly associated with thermoregulatory changes.
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Affiliation(s)
- Kurt Kräuchi
- Psychiatric University Clinics, Centre for Chronobiology, Wilhelm Klein Strasse 27, H4025 Basel, Switzerland.
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25
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Cajochen C, Jud C, Münch M, Kobialka S, Wirz-Justice A, Albrecht U. Evening exposure to blue light stimulates the expression of the clock genePER2in humans. Eur J Neurosci 2006; 23:1082-6. [PMID: 16519674 DOI: 10.1111/j.1460-9568.2006.04613.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We developed a non-invasive method to measure and quantify human circadian PER2 gene expression in oral mucosa samples and show that this gene oscillates in a circadian (= about a day) fashion. We also have the first evidence that induction of human PER2 expression is stimulated by exposing subjects to 2 h of light in the evening. This increase in PER2 expression was statistically significant in comparison to a non-light control condition only after light at 460 nm (blue) but not after light exposure at 550 nm (green). Our results indicate that the non-image-forming visual system is involved in human circadian gene expression. The demonstration of a functional circadian machinery in human buccal samples and its response to light opens the door for investigation of human circadian rhythms at the gene level and their associated disorders.
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Affiliation(s)
- Christian Cajochen
- Centre for Chronobiology, Psychiatric University Clinics, University of Basel, CH-4025 Basel, Switzerland.
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26
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Münch M, Knoblauch V, Blatter K, Schröder C, Schnitzler C, Kräuchi K, Wirz-Justice A, Cajochen C. Age-related attenuation of the evening circadian arousal signal in humans. Neurobiol Aging 2005; 26:1307-19. [PMID: 16182904 DOI: 10.1016/j.neurobiolaging.2005.03.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 03/09/2005] [Accepted: 03/15/2005] [Indexed: 11/19/2022]
Abstract
The human circadian pacemaker maintains timing and consolidation of sleep-wake behavior by opposing the build-up of homeostatic sleep pressure during the wake episode, particularly in the evening during the 'wake maintenance zone'. We tested whether age-related changes in sleep are a consequence of a weaker circadian arousal signal in the evening. Circadian rhythms and spectral components of the sleep EEG were investigated in 17 young (20-31 year) and 15 older (57-74 year) volunteers under constant posture conditions during a 40-h nap protocol (75/150 min sleep/wake schedule). Quantitative evidence for a weaker circadian arousal signal in aging arose from significantly more sleep occurring during the wake maintenance zone and higher subjective sleepiness ratings in the late afternoon and evening in the older group. In addition, we found a diminished melatonin secretion and a reduced circadian modulation of REM sleep together with less pronounced day-night differences in the lower alpha and spindle range of sleep EEG activity in the older group. Thus, our data indicate that age-related changes in sleep propensity are clearly related to a reduced circadian signal opposing the homeostatic drive for sleep.
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Affiliation(s)
- Mirjam Münch
- Centre for Chronobiology, University Psychiatric Hospitals, Wilhelm-Kleinstr. 27, CH-4025 Basel, Switzerland
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27
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De Gennaro L, Ferrara M, Vecchio F, Curcio G, Bertini M. An electroencephalographic fingerprint of human sleep. Neuroimage 2005; 26:114-22. [PMID: 15862211 DOI: 10.1016/j.neuroimage.2005.01.020] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 12/21/2004] [Accepted: 01/13/2005] [Indexed: 02/05/2023] Open
Abstract
Homeostatic and circadian processes are basic mechanisms of human sleep which challenge the common knowledge of large individual variations in sleep need or differences in circadian types. However, since sleep research has mostly focused on group measures, an approach which emphasizes the similarities between subjects, the biological foundations of the individual differences in normal sleep are still poorly understood. In the present work, we assessed individual differences in a range of EEG frequencies including sigma activity during non-REM sleep (8.0-15.5 Hz range) in a group of 10 subjects who had participated in a slow-wave sleep (SWS) deprivation study. We showed that, like a "fingerprint", a particular topographic distribution of the electroencephalogram (EEG) power along the antero-posterior cortical axis distinguishes each individual during non-REM sleep. This individual EEG-trait is substantially invariant across six consecutive nights characterized by large experimentally induced changes of sleep architecture. One possible hypothesis is that these EEG invariances can be related to individual differences in genetically determined functional brain anatomy, rather than to sleep-dependent mechanisms.
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Affiliation(s)
- Luigi De Gennaro
- Department of Psychology, University of Rome La Sapienza, Italy.
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28
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Himanen SL, Hasan J. Response to "sleep spindles: an overview". Sleep Med Rev 2004; 8:149. [PMID: 15033153 DOI: 10.1016/j.smrv.2003.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 11/18/2003] [Indexed: 10/26/2022]
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29
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Knoblauch V, Martens WLJ, Wirz-Justice A, Cajochen C. Human sleep spindle characteristics after sleep deprivation. Clin Neurophysiol 2004; 114:2258-67. [PMID: 14652085 DOI: 10.1016/s1388-2457(03)00238-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Sleep spindles (12-15 Hz oscillations) are one of the hallmarks of the electroencephalogram (EEG) during human non-rapid eye movement (non-REM) sleep. The effect of a 40 h sleep deprivation (SD) on spindle characteristics along the antero-posterior axis was investigated. METHODS EEGs during non-REM sleep in healthy young volunteers were analyzed with a new method for instantaneous spectral analysis, based on the fast time frequency transform (FTFT), which yields high-resolution spindle parameters in the combined time and frequency domain. RESULTS FTFT revealed that after SD, mean spindle amplitude was enhanced, while spindle density was reduced. The reduction in spindle density was most prominent in the frontal derivation (Fz), while spindle amplitude was increased in all derivations except in Fz. Mean spindle frequency and its variability within a spindle were reduced after SD. When analyzed per 0.25 Hz frequency bin, amplitude was increased in the lower spindle frequency range (12-13.75 Hz), whereas density was reduced in the high spindle frequency range (13.5-14.75 Hz). CONCLUSIONS The observed reduction in spindle density after SD confirms the inverse homeostatic relationship between sleep spindles and slow waves whereas the increase in spindle amplitude and the reduction in intra-spindle frequency variability support the hypothesis of a higher level of synchronization in thalamocortical cells when homeostatic sleep pressure is enhanced.
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Affiliation(s)
- Vera Knoblauch
- Centre for Chronobiology, Psychiatric University Clinic, Wilhelm Klein-Str. 27, CH-4025 Basel, Switzerland
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30
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CAJOCHEN C, DIJK DJ. Electroencephalographic activity during wakefulness, rapid eye movement and non-rapid eye movement sleep in humans: Comparison of their circadian and homeostatic modulation. Sleep Biol Rhythms 2003. [DOI: 10.1046/j.1446-9235.2003.00041.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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