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Varma P, Postnova S, Knock S, Howard ME, Aidman E, Rajaratnam SWM, Sletten TL. SleepSync: Early Testing of a Personalised Sleep-Wake Management Smartphone Application for Improving Sleep and Cognitive Fitness in Defence Shift Workers. Clocks Sleep 2024; 6:267-280. [PMID: 38920420 PMCID: PMC11203003 DOI: 10.3390/clockssleep6020019] [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: 04/10/2024] [Revised: 05/27/2024] [Accepted: 05/27/2024] [Indexed: 06/27/2024] Open
Abstract
Shift work, long work hours, and operational tasks contribute to sleep and circadian disruption in defence personnel, with profound impacts on cognition. To address this, a digital technology, the SleepSync app, was designed for use in defence. A pre-post design study was undertaken to examine whether four weeks app use improved sleep and cognitive fitness (high performance neurocognition) in a cohort of shift workers from the Royal Australian Air Force. In total, 13 of approximately 20 shift-working personnel from one base volunteered for the study. Sleep outcomes were assessed using the Insomnia Severity Index (ISI), the Patient-Reported Outcomes Measurement Information System (PROMIS), Sleep Disturbance and Sleep-Related Impairment Scales, the Glasgow Sleep Effort Scale, the Sleep Hygiene Index, and mental health was assessed using the Depression, Anxiety, and Stress Scale-21. Sustained attention was measured using the 3-min Psychomotor Vigilance Task (PVT) and controlled response using the NBack. Results showed significant improvements in insomnia (ISI scores 10.31 at baseline and 7.50 after app use), sleep-related impairments (SRI T-scores 53.03 at baseline to 46.75 post-app use), and healthy sleep practices (SHI scores 21.61 at baseline to 18.83 post-app use; all p < 0.001). Trends for improvement were recorded for depression. NBack incorrect responses reduced significantly (9.36 at baseline; reduced by -3.87 at last week of app use, p < 0.001), but no other objective measures improved. These findings suggest that SleepSync may improve sleep and positively enhance cognitive fitness but warrants further investigation in large samples. Randomised control trials with other cohorts of defence personnel are needed to confirm the utility of this intervention in defence settings.
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Affiliation(s)
- Prerna Varma
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, VIC 3168, Australia
| | - Svetlana Postnova
- School of Physics, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Stuart Knock
- School of Physics, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Mark E. Howard
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, VIC 3168, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC 3084, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eugene Aidman
- Defence, Science and Technology Group, Department of Defence, Edinburgh, SA 5111, Australia;
- School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Shantha W. M. Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, VIC 3168, Australia
- School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Tracey L. Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, VIC 3168, Australia
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Cortical waste clearance in normal and restricted sleep with potential runaway tau buildup in Alzheimer's disease. Sci Rep 2022; 12:13740. [PMID: 35961995 PMCID: PMC9374764 DOI: 10.1038/s41598-022-15109-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 06/17/2022] [Indexed: 01/10/2023] Open
Abstract
Accumulation of waste in cortical tissue and glymphatic waste clearance via extracellular voids partly drives the sleep-wake cycle and modeling has reproduced much of its dynamics. Here, new modeling incorporates higher void volume and clearance in sleep, multiple waste compounds, and clearance obstruction by waste. This model reproduces normal sleep-wake cycles, sleep deprivation effects, and performance decreases under chronic sleep restriction (CSR). Once fitted to calibration data, it successfully predicts dynamics in further experiments on sleep deprivation, intermittent CSR, and recovery after restricted sleep. The results imply a central role for waste products with lifetimes similar to tau protein. Strong tau buildup is predicted if pathologically enhanced production or impaired clearance occur, with runaway buildup above a critical threshold. Predicted tau accumulation has timescales consistent with the development of Alzheimer’s disease. The model unifies a wide sweep of phenomena, clarifying the role of glymphatic clearance and targets for interventions against waste buildup.
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The 5-HT and PLC Signaling Pathways Regulate the Secretion of IL-1β, TNF-α and BDNF from NG2 Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:7425538. [PMID: 35600957 PMCID: PMC9122684 DOI: 10.1155/2022/7425538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 01/26/2023]
Abstract
The present study was clarified the relationship between NG2 glial cells and 5-hydroxytryptamine (5-HT) to further revealed a role in the regulation of cortical excitability. The co-localization of NG2 cells and 5-HT in rat prefrontal cortex was determined using immunofluorescence. Different concentrations of 5-HT were applied to cultured NG2 cells. Real-time PCR measured the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and brain-derived neurotrophic factor (BDNF). Changes in the expression of IL-1β, TNF-α, and BDNF in NG2 cells were detected after the addition of 5-HT receptor specific blockers and phospholipase C (PLC) specific activators and inhibitors. The results confirmed that the NG2 protein and 5-HT co-localized in the prefrontal cortex. 5-HT treatment of NG2 cells significantly reduced the expression of IL-1β and BDNF mRNA and increased the expression of TNF-α. The 5-HT receptor specific inhibitors alverine citrate, ketanserin, ondansetron and SB-399885 blocked the regulatory effects of 5-HT on NG2 cells. The PLC signal was linked to the secretion of IL-1β, TNF-α and BDNF in NG2 cells. These results indicated that 5-HT affected IL-1β, TNF-α, and BDNF secretion from NG2 cells via the 5-HT1A, 5-HT2A, 5-HT3, 5-HT6 receptors and the PLC signaling pathway.
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Progress in modelling of brain dynamics during anaesthesia and the role of sleep-wake circuitry. Biochem Pharmacol 2021; 191:114388. [DOI: 10.1016/j.bcp.2020.114388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/28/2022]
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From circadian clock mechanism to sleep disorders and jet lag: Insights from a computational approach. Biochem Pharmacol 2021; 191:114482. [DOI: 10.1016/j.bcp.2021.114482] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
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Torres FA, Orio P, Escobar MJ. Selection of stimulus parameters for enhancing slow wave sleep events with a neural-field theory thalamocortical model. PLoS Comput Biol 2021; 17:e1008758. [PMID: 34329289 PMCID: PMC8357165 DOI: 10.1371/journal.pcbi.1008758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 08/11/2021] [Accepted: 05/28/2021] [Indexed: 11/30/2022] Open
Abstract
Slow-wave sleep cortical brain activity, conformed by slow-oscillations and sleep spindles, plays a key role in memory consolidation. The increase of the power of the slow-wave events, obtained by auditory sensory stimulation, positively correlates with memory consolidation performance. However, little is known about the experimental protocol maximizing this effect, which could be induced by the power of slow-oscillation, the number of sleep spindles, or the timing of both events' co-occurrence. Using a mean-field model of thalamocortical activity, we studied the effect of several stimulation protocols, varying the pulse shape, duration, amplitude, and frequency, as well as a target-phase using a closed-loop approach. We evaluated the effect of these parameters on slow-oscillations (SO) and sleep-spindles (SP), considering: (i) the power at the frequency bands of interest, (ii) the number of SO and SP, (iii) co-occurrences between SO and SP, and (iv) synchronization of SP with the up-peak of the SO. The first three targets are maximized using a decreasing ramp pulse with a pulse duration of 50 ms. Also, we observed a reduction in the number of SO when increasing the stimulus energy by rising its amplitude. To assess the target-phase parameter, we applied closed-loop stimulation at 0°, 45°, and 90° of the phase of the narrow-band filtered ongoing activity, at 0.85 Hz as central frequency. The 0° stimulation produces better results in the power and number of SO and SP than the rhythmic or random stimulation. On the other hand, stimulating at 45° or 90° change the timing distribution of spindles centers but with fewer co-occurrences than rhythmic and 0° phase. Finally, we propose the application of closed-loop stimulation at the rising zero-cross point using pulses with a decreasing ramp shape and 50 ms of duration for future experimental work.
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Affiliation(s)
- Felipe A. Torres
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, Valparaíso, Chile
- Advanced Center for Electrical and Electronic Engineering (AC3E), Valparaíso, Chile
| | - Patricio Orio
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Advanced Center for Electrical and Electronic Engineering (AC3E), Valparaíso, Chile
| | - María-José Escobar
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, Valparaíso, Chile
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Androulakis IP. Circadian rhythms and the HPA axis: A systems view. WIREs Mech Dis 2021; 13:e1518. [PMID: 33438348 DOI: 10.1002/wsbm.1518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022]
Abstract
The circadian timing system comprises a network of time-keeping clocks distributed across a living host whose responsibility is to allocate resources and distribute functions temporally to optimize fitness. The molecular structures generating these rhythms have evolved to accommodate the rotation of the earth in an attempt to primarily match the light/dark periods during the 24-hr day. To maintain synchrony of timing across and within tissues, information from the central clock, located in the suprachiasmatic nucleus, is conveyed using systemic signals. Leading among those signals are endocrine hormones, and while the hypothalamic-pituitary-adrenal axis through the release of glucocorticoids is a major pacesetter. Interestingly, the fundamental units at the molecular and physiological scales that generate local and systemic signals share critical structural properties. These properties enable time-keeping systems to generate rhythmic signals and allow them to adopt specific properties as they interact with each other and the external environment. The purpose of this review is to provide a broad overview of these structures, discuss their functional characteristics, and describe some of their fundamental properties as these related to health and disease. This article is categorized under: Immune System Diseases > Computational Models Immune System Diseases > Biomedical Engineering.
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Affiliation(s)
- Ioannis P Androulakis
- Biomedical Engineering Department, Chemical & Biochemical Engineering Department, Rutgers University, New Brunswick, New Jersey.,Department of Surgery, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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Tekieh T, Lockley SW, Robinson PA, McCloskey S, Zobaer MS, Postnova S. Modeling melanopsin-mediated effects of light on circadian phase, melatonin suppression, and subjective sleepiness. J Pineal Res 2020; 69:e12681. [PMID: 32640090 DOI: 10.1111/jpi.12681] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/05/2020] [Accepted: 07/01/2020] [Indexed: 12/14/2022]
Abstract
A physiologically based model of arousal dynamics is improved to incorporate the effects of the light spectrum on circadian phase resetting, melatonin suppression, and subjective sleepiness. To account for these nonvisual effects of light, melanopic irradiance replaces photopic illuminance that was used previously in the model. The dynamic circadian oscillator is revised according to the melanopic irradiance definition and tested against experimental circadian phase resetting dose-response and phase response data. Melatonin suppression function is recalibrated against melatonin dose-response data for monochromatic and polychromatic light sources. A new light-dependent term is introduced into the homeostatic weight component of subjective sleepiness to represent the direct alerting effect of light; the new term responds to light change in a time-dependent manner and is calibrated against experimental data. The model predictions are compared to a total of 14 experimental studies containing 26 data sets for 14 different spectral light profiles. The revised melanopic model shows on average 1.4 times lower prediction error for circadian phase resetting compared to the photopic-based model, 3.2 times lower error for melatonin suppression, and 2.1 times lower error for subjective sleepiness. Overall, incorporating melanopic irradiance allowed simulation of wavelength-dependent responses to light and could explain the majority of the observations. Moving forward, models of circadian phase resetting and the direct effects of light on alertness and sleep need to use nonvisual photoreception-based measures of light, for example, melanopic irradiance, instead of the traditionally used illuminance based on the visual system.
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Affiliation(s)
- Tahereh Tekieh
- School of Physics, University of Sydney, Sydney, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
- Centre of Excellence for Integrative Brain Function, University of Sydney, Sydney, NSW, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Vic., Australia
| | - Peter A Robinson
- School of Physics, University of Sydney, Sydney, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
- Centre of Excellence for Integrative Brain Function, University of Sydney, Sydney, NSW, Australia
- Centre for Translational Sleep and Circadian Neurobiology, University of Sydney, Sydney, NSW, Australia
| | - Stephen McCloskey
- School of Physics, University of Sydney, Sydney, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
| | - M S Zobaer
- School of Physics, University of Sydney, Sydney, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
| | - Svetlana Postnova
- School of Physics, University of Sydney, Sydney, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Vic., Australia
- Centre of Excellence for Integrative Brain Function, University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
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Abel JH, Lecamwasam K, Hilaire MAS, Klerman EB. Recent advances in modeling sleep: from the clinic to society and disease. CURRENT OPINION IN PHYSIOLOGY 2020; 15:37-46. [PMID: 34485783 PMCID: PMC8415470 DOI: 10.1016/j.cophys.2019.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the past few decades, advances in understanding sleep-wake neurophysiology have occurred hand-in-hand with advances in mathematical modeling of sleep and wake. In this review, we summarize recent updates in modeling the timing and durations of sleep and wake, the underlying neurophysiology of sleep and wake, and the application of these models in understanding cognition and disease. Throughout, we highlight the role modeling has played in developing our understanding of sleep and its underlying mechanisms. We present open questions and controversies in the field and propose the utility of individualized models of sleep for precision sleep medicine.
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Affiliation(s)
- John H Abel
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115
| | | | - Melissa A St Hilaire
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | - Elizabeth B Klerman
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114
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