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Author Dumont, M.; Beaulieu, C. url  doi
openurl 
  Title Light exposure in the natural environment: relevance to mood and sleep disorders Type Journal Article
  Year 2007 Publication Sleep Medicine Abbreviated Journal Sleep Med  
  Volume 8 Issue 6 Pages (down) 557-565  
  Keywords Human Health; Affect; *Biological Clocks; *Circadian Rhythm; Humans; *Light; Mood Disorders/*etiology; Sleep Disorders, Circadian Rhythm/*complications; Wakefulness; Work Schedule Tolerance  
  Abstract In addition to being necessary for vision, light also plays a primary role in circadian physiology. Humans are diurnal animals and their biological clock synchronizes their physiological functions in such a way that functions associated with activity happen in the daytime while functions associated with rest occur at night. A misalignment between the endogenous circadian clock and the desired sleep schedule is the main cause of circadian sleep disorders; it may be involved in certain mood disorders as well. Since light is the main environmental cue used by the biological clock to set its own timing in relation to the day-night cycle, inappropriate light exposure can be involved in the physiopathology of circadian disorders. Conversely, when handled properly, controlled light exposure can be used to treat some mood and sleep disorders. While the earliest studies in the field focused solely on exposure to bright light, contemporary studies aim at understanding how the entire profile of light-dark exposure can influence the circadian clock and, consequently, mood, sleep, and vigilance quality. Following a brief summary of the main concepts underlying the non-visual effects of light, this paper presents some studies using ambulatory measurements of light exposure to illustrate how these concepts apply in real-life situations and discusses the clinical relevance of light exposure in the natural environment for mood, sleep, and circadian disorders.  
  Address Chronobiology Laboratory, Sacre-Coeur Hospital of Montreal, Montreal, Quebec, Canada H4J 1C5. marie.dumont@umontreal.ca  
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  Language English Summary Language Original Title  
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  ISSN 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17383230 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 736  
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Author Walbeek, T.J.; Harrison, E.M.; Soler, R.R.; Gorman, M.R. url  doi
openurl 
  Title Enhanced Circadian Entrainment in Mice and Its Utility under Human Shiftwork Schedules Type Journal Article
  Year 2019 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep  
  Volume 1 Issue 3 Pages (down) 394-413  
  Keywords Animals  
  Abstract The circadian system is generally considered to be incapable of adjusting to rapid changes in sleep/work demands. In shiftworkers this leads to chronic circadian disruption and sleep loss, which together predict underperformance at work and negative health consequences. Two distinct experimental protocols have been proposed to increase circadian flexibility in rodents using dim light at night: rhythm bifurcation and T-cycle (i.e., day length) entrainment. Successful translation of such protocols to human shiftworkers could facilitate alignment of internal time with external demands. To assess entrainment flexibility following bifurcation and exposure to T-cycles, mice in Study 1 were repeatedly phase-shifted. Mice from experimental conditions rapidly phase-shifted their activity, while control mice showed expected transient misalignment. In Study 2 and 3, mice followed a several weeks-long intervention designed to model a modified DuPont or Continental shiftwork schedule, respectively. For both schedules, bifurcation and nocturnal dim lighting reduced circadian misalignment. Together, these studies demonstrate proof of concept that mammalian circadian systems can be rendered sufficiently flexible to adapt to multiple, rapidly changing shiftwork schedules. Flexible adaptation to exotic light-dark cycles likely relies on entrainment mechanisms that are distinct from traditional entrainment.  
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  ISSN 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2661  
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Author Komada, Y.; Aoki, K.; Gohshi, S.; Ichioka, H.; Shibata, S. url  doi
openurl 
  Title Effects of television luminance and wavelength at habitual bedtime on melatonin and cortisol secretion in humans: Blue light and melatonin secretion Type Journal Article
  Year 2015 Publication Sleep and Biological Rhythms Abbreviated Journal Sleep and Biological Rhythms  
  Volume 13 Issue 4 Pages (down) 316–322  
  Keywords Human Health  
  Abstract The aim of this study was to examine the effect of exposure to different types of television displays at habitual bedtime on human melatonin and cortisol secretion. Thirteen male participants (mean age: 22.7 ± 0.85 years) were tested over three nights in one baseline and two experimental sessions. Participants were instructed to watch a movie on four different luminance- and wavelength-controlled television displays: normal luminance (450 candela [cd]/m2) or high luminance (1200 cd/m2) and normal blue light or half blue light. Salivary melatonin and cortisol levels were measured at two time points before and after television viewing. There was no significant difference in cortisol secretion due to the different displays. Melatonin suppression was significantly lower following the exposure to the half-blue light display compared with the normal blue light display. These results suggest that the use of half-blue light displays during night time may prevent circadian rhythm dysfunction.  
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  ISSN 1446-9235 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 1149  
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Author Panagiotou, M.; Rohling, J.H.T.; Deboer, T. url  doi
openurl 
  Title Sleep Network Deterioration as a Function of Dim-Light-At-Night Exposure Duration in a Mouse Model Type Journal Article
  Year 2020 Publication Clocks & Sleep Abbreviated Journal Clocks & Sleep  
  Volume 2 Issue 3 Pages (down) 308-324  
  Keywords Animals  
  Abstract Artificial light, despite its widespread and valuable use, has been associated withdeterioration of health and well-being, including altered circadian timing and sleep disturbances,particularly in nocturnal exposure. Recent findings from our lab reveal significant sleep andsleep electroencephalogram (EEG) changes owing to three months exposure to dim-light-at-night(DLAN). Aiming to further explore the detrimental effects of DLAN exposure, in the present study,we continuously recorded sleep EEG and the electromyogram for baseline 24-h and following 6-h sleepdeprivation in a varied DLAN duration scheme. C57BL/6J mice were exposed to a 12:12 h light:DLANcycle (75lux:5lux) vs. a 12:12 h light:dark cycle (75lux:0lux) for one day, one week, and one month.Our results show that sleep was already affected by a mere day of DLAN exposure with additionalcomplications emerging with increasing DLAN exposure duration, such as the gradual delay ofthe daily 24-h vigilance state rhythms. We conducted detrended fluctuation analysis (DFA) on thelocomotor activity data following 1-month and 3-month DLAN exposure, and a significantly lesshealthy rest-activity pattern, based on the decreased alpha values, was found in both conditionscompared to the control light-dark. Taking into account the behavioral, sleep and the sleep EEGparameters, our data suggest that DLAN exposure, even in the shortest duration, induces deleteriouseffects; nevertheless, potential compensatory mechanisms render the organism partly adjustable andable to cope. We think that, for this reason, our data do not always depict linear divergence amonggroups, as compared with control conditions. Chronic DLAN exposure impacts the sleep regulatorysystem, but also brain integrity, diminishing its adaptability and reactivity, especially apparent in thesleep EEG alterations and particular low alpha values following DFA.  
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  ISSN 2624-5175 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 3078  
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Author Lack, L.C.; Gradisar, M.; Van Someren, E.J.W.; Wright, H.R.; Lushington, K. url  doi
openurl 
  Title The relationship between insomnia and body temperatures Type Journal Article
  Year 2008 Publication Sleep Medicine Reviews Abbreviated Journal Sleep Med Rev  
  Volume 12 Issue 4 Pages (down) 307-317  
  Keywords Human Health; Arousal/physiology; Body Temperature Regulation/*physiology; Circadian Rhythm/physiology; Homeostasis/physiology; Humans; Melatonin/blood; Phototherapy; Skin Temperature/physiology; Sleep Disorders, Circadian Rhythm/physiopathology/therapy; Sleep Initiation and Maintenance Disorders/*physiopathology/therapy; Sympathetic Nervous System/physiopathology; Wakefulness/physiology  
  Abstract Sleepiness and sleep propensity are strongly influenced by our circadian clock as indicated by many circadian rhythms, most commonly by that of core body temperature. Sleep is most conducive in the temperature minimum phase, but is inhibited in a “wake maintenance zone” before the minimum phase, and is disrupted in a zone following that phase. Different types of insomnia symptoms have been associated with abnormalities of the body temperature rhythm. Sleep onset insomnia is associated with a delayed temperature rhythm presumably, at least partly, because sleep is attempted during a delayed evening wake maintenance zone. Morning bright light has been used to phase advance circadian rhythms and successfully treat sleep onset insomnia. Conversely, early morning awakening insomnia has been associated with a phase advanced temperature rhythm and has been successfully treated with the phase delaying effects of evening bright light. Sleep maintenance insomnia has been associated not with a circadian rhythm timing abnormality, but with nocturnally elevated core body temperature. Combination of sleep onset and maintenance insomnia has been associated with a 24-h elevation of core body temperature supporting the chronic hyper-arousal model of insomnia. The possibility that these last two types of insomnia may be related to impaired thermoregulation, particularly a reduced ability to dissipate body heat from distal skin areas, has not been consistently supported in laboratory studies. Further studies of thermoregulation are needed in the typical home environment in which the insomnia is most evident.  
  Address School of Psychology, Flinders University, South Australia, Australia. leon.lack@flinders.edu.au  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1087-0792 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18603220 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 775  
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