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Author LeGates, T.A.; Fernandez, D.C.; Hattar, S.
Title Light as a central modulator of circadian rhythms, sleep and affect Type Journal Article
Year 2014 Publication Nature Reviews. Neuroscience Abbreviated Journal Nat Rev Neurosci
Volume 15 Issue 7 Pages 443-454
Keywords Human Health; photobiology; circadian disruption; asynchronization; sleep; mood; Review
Abstract Light has profoundly influenced the evolution of life on earth. As widely appreciated, light enables us to generate images of our environment. However, light – through intrinsically photosensitive retinal ganglion cells (ipRGCs) – also influences behaviours that are essential for our health and quality of life but are independent of image formation. These include the synchronization of the circadian clock to the solar day, tracking of seasonal changes and the regulation of sleep. Irregular light environments lead to problems in circadian rhythms and sleep, which eventually cause mood and learning deficits. Recently, it was found that irregular light can also directly affect mood and learning without producing major disruptions in circadian rhythms and sleep. In this Review, we discuss the indirect and direct influence of light on mood and learning, and provide a model for how light, the circadian clock and sleep interact to influence mood and cognitive functions.
Address 1] Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218, USA. [2] Johns Hopkins University, Department of Neuroscience, Baltimore, Maryland 21218, USA
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1471-003X ISBN Medium
Area Expedition Conference
Notes PMID:24917305 Approved no
Call Number IDA @ john @ Serial 299
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Author Higuchi, S.; Nagafuchi, Y.; Lee, S.-I.; Harada, T.
Title Influence of Light at Night on Melatonin Suppression in Children Type Journal Article
Year 2014 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume 99 Issue 9 Pages 3298-3303
Keywords melatonin; light at night; photobiology; children
Abstract Context: The sensitivity of melatonin to light suppression is expected to be higher in children since children have large pupils and pure crystal lenses. However, melatonin suppression by light in children remains unclear. Objective: We investigated whether light-induced melatonin suppression in children is larger than that in adults. Methods: Thirty-three healthy primary school children (mean age: 7.4 +/- 1.8 yr) and 29 healthy adults (mean age: 41.2 +/- 4.8 yr) participated in two experiments. In the first experiment, salivary melatonin concentrations in 13 children and 13 adults were measured at night under a dim light (< 30 lx) and moderately bright light (580 lx) in an experimental facility. Pupil diameters were also measured under dim light and bright light. In the second experiment, melatonin concentrations in 20 children and 16 adults were measured under dim light in the experimental facility and under room light at home (illuminance 140.0 +/- 82.7 lx). Results: In the experiment 1, the melatonin concentration was significantly decreased by exposure to moderately bright light in both adults and children. Melatonin suppression was significantly larger in children (88.2%, n=5) than in adults (46.3%, n=6) (p<0.01), although the data for some participants were excluded because melatonin concentrations had not yet risen. In the experiment 2, melatonin secretion was significantly suppressed by room light at home in children (n=15) (p<0.05) but not in adults (n=11). Conclusion: We found that the percentage of melatonin suppression by light in children was almost twice that in adults, suggesting that melatonin in children is more sensitive than that in adults to light at night.
Address Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan
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Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:24840814 Approved no
Call Number IDA @ john @ Serial 300
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Author Chellappa, S.L.; Viola, A.U.; Schmidt, C.; Bachmann, V.; Gabel, V.; Maire, M.; Reichert, C.F.; Valomon, A.; Gotz, T.; Landolt, H.-P.; Cajochen, C.
Title Human melatonin and alerting response to blue-enriched light depend on a polymorphism in the clock gene PER3 Type Journal Article
Year 2012 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume 97 Issue 3 Pages E433-7
Keywords Adult; Alleles; Cross-Over Studies; Female; Genotype; Homozygote; Humans; *Light; Male; Melatonin/*blood/genetics; *Minisatellite Repeats; Period Circadian Proteins/*genetics; *Polymorphism, Genetic; Questionnaires; Sleep/genetics; Wakefulness/*genetics
Abstract CONTEXT: Light exposure, particularly at the short-wavelength range, triggers several nonvisual responses in humans. However, the extent to which the melatonin-suppressing and alerting effect of light differs among individuals remains unknown. OBJECTIVE: Here we investigated whether blue-enriched polychromatic light impacts differentially on melatonin and subjective and objective alertness in healthy participants genotyped for the PERIOD3 (PER3) variable-number, tandem-repeat polymorphism. DESIGN, SETTING, AND PARTICIPANTS: Eighteen healthy young men homozygous for the PER3 polymorphism (PER3(5/5)and PER3(4/4)) underwent a balanced crossover design during the winter season, with light exposure to compact fluorescent lamps of 40 lux at 6500 K and at 2500 K during 2 h in the evening. RESULTS: In comparison to light at 2500 K, blue-enriched light at 6500 K induced a significant suppression of the evening rise in endogenous melatonin levels in PER3(5/5) individuals but not in PER3(4/4). Likewise, PER3(5/5) individuals exhibited a more pronounced alerting response to light at 6500 K than PER3(4/4) volunteers. Waking electroencephalographic activity in the theta range (5-7 Hz), a putative correlate of sleepiness, was drastically attenuated during light exposure at 6500 K in PER3(5/5) individuals as compared with PER3(4/4). CONCLUSIONS: We provide first evidence that humans homozygous for the PER3 5/5 allele are particularly sensitive to blue-enriched light, as indexed by the suppression of endogenous melatonin and waking theta activity. Light sensitivity in humans may be modulated by a clock gene polymorphism implicated in the sleep-wake regulation.
Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Wilhelm Kleinstrasse 27, CH-4012 Basel, Switzerland
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Language English Summary Language Original Title
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ISSN 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:22188742 Approved no
Call Number IDA @ john @ Serial 301
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Author Martinez-Nicolas, A.; Ortiz-Tudela, E.; Madrid, J.A.; Rol, M.A.
Title Crosstalk between environmental light and internal time in humans Type Journal Article
Year 2011 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 28 Issue 7 Pages 617-629
Keywords Adolescent; Biological Clocks/*physiology; Circadian Rhythm/*physiology; Cues; *Environment; Female; Humans; *Light; Male; Sleep; Spain; Temperature; *Time; Young Adult
Abstract Daily exposure to environmental light is the most important zeitgeber in humans, and all studied characteristics of light pattern (timing, intensity, rate of change, duration, and spectrum) influence the circadian system. However, and due to lack of current studies on environmental light exposure and its influence on the circadian system, the aim of this work is to determine the characteristics of a naturalistic regimen of light exposure and its relationship with the functioning of the human circadian system. Eighty-eight undergraduate students (18-23 yrs) were recruited in Murcia, Spain (latitude 38 degrees 01'N) to record wrist temperature (WT), light exposure, and sleep for 1 wk under free-living conditions. Light-exposure timing, rate of change, regularity, intensity, and contrast were calculated, and their effects on the sleep pattern and WT rhythm were then analyzed. In general, higher values for interdaily stability, relative amplitude, mean morning light, and light quality index (LQI) correlated with higher interdaily stability and relative amplitude, and phase advance in sleep plus greater stability in WT and phase advance of the WT circadian rhythm. On the other hand, a higher fragmentation of the light-exposure rhythm was associated with more fragmented sleep. Naturalistic studies using 24-h ambulatory light monitoring provide essential information about the main circadian system input, necessary for maintaining healthy circadian tuning. Correcting light-exposure patterns accordingly may help prevent or even reverse health problems associated with circadian disruption.
Address Chronobiology Laboratory, Department of Physiology, University of Murcia, Murcia, Spain
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Language English Summary Language Original Title
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ISSN 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:21793693 Approved no
Call Number IDA @ john @ Serial 302
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Author Sharkey, K.M.; Carskadon, M.A.; Figueiro, M.G.; Zhu, Y.; Rea, M.S.
Title Effects of an advanced sleep schedule and morning short wavelength light exposure on circadian phase in young adults with late sleep schedules Type Journal Article
Year 2011 Publication Sleep Medicine Abbreviated Journal Sleep Med
Volume 12 Issue 7 Pages 685-692
Keywords Affect/physiology/radiation effects; Circadian Rhythm/*physiology/*radiation effects; Color; Dose-Response Relationship, Radiation; Female; Humans; *Light; Male; Melatonin/metabolism; Photoperiod; Phototherapy/*methods; Saliva/metabolism; Sleep/physiology/radiation effects; Sleep Disorders, Circadian Rhythm/prevention & control/*therapy; Stress, Psychological/prevention & control/therapy; Treatment Outcome; Young Adult; blue light
Abstract OBJECTIVE: We examined the effects of an advanced sleep/wake schedule and morning short wavelength (blue) light in 25 adults (mean age+/-SD=21.8+/-3 years; 13 women) with late sleep schedules and subclinical features of delayed sleep phase disorder (DSPD). METHODS: After a baseline week, participants kept individualized, fixed, advanced 7.5-h sleep schedules for 6days. Participants were randomly assigned to groups to receive “blue” (470nm, approximately 225lux, n=12) or “dim” (<1lux, n=13) light for 1h after waking each day. Head-worn “Daysimeters” measured light exposure; actigraphs and sleep diaries confirmed schedule compliance. Salivary dim light melatonin onset (DLMO), self-reported sleep, and mood were examined with 2x2 ANOVA. RESULTS: After 6days, both groups showed significant circadian phase advances, but morning blue light was not associated with larger phase shifts than dim-light exposure. The average DLMO advances (mean+/-SD) were 1.5+/-1.1h in the dim light group and 1.4+/-0.7h in the blue light group. CONCLUSIONS: Adherence to a fixed advanced sleep/wake schedule resulted in significant circadian phase shifts in young adults with subclinical DSPD with or without morning blue light exposure. Light/dark exposures associated with fixed early sleep schedules are sufficient to advance circadian phase in young adults.
Address Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Alpert Medical School of Brown University, Box G-RIH, Providence, RI 02912, USA. katherine_sharkey@brown.edu
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:21704557; PMCID:PMC3145013 Approved no
Call Number IDA @ john @ Serial 303
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