References of "Chellappa, Sarah Laxhmi"
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See detailCircadian Rhythm Sleep Disorder: Genetic and Environmental Factors
Chellappa, Sarah Laxhmi ULg; Viola, Antoine; Mongrain, Valerie

in Kushida, Clete (Ed.) Encyclopaedia of Sleep (in press)

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See detailCircadian and homeostatic regulation of sleepiness and cognition and its neuronal underpinnings
Schmidt, Christina; Chellappa, Sarah Laxhmi ULg; Cajochen, Christian

in Garbarino, Sergio (Ed.) Sleepiness and Human Impact Assessment (in press)

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See detailTwo time pieces for sleep regulation: the circadian clock and the homeostatic hourglass
Cajochen, Christian; Schmidt, Christina; Chellappa, Sarah Laxhmi ULg

in Garbarino, Sergio (Ed.) Sleepiness and Human Impact Assessment (in press)

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See detailEvolution of Treatment and Investigative Approaches in Sleep Medicine
Ly, Julien; Chellappa, Sarah Laxhmi ULg; MAQUET, Pierre ULg

in Billiard, Michael (Ed.) Sleep Medicine: a comprehensive guide (in press)

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See detailNeurophysiological basis of sleep and wakefulness
Chellappa, Sarah Laxhmi ULg; Schmidt, Christina; Cajochen, Christian

in Garbarino, Sergio (Ed.) Sleepiness and Human Impact Assessment (in press)

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See detailPrior light history impacts on higher order cognitive brain function
Chellappa, Sarah Laxhmi ULg; Ly, Julien; Meyer, Christelle ULg et al

Conference (2014, June 17)

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See detailThe circadian system sets the temporal organization of basic human neuronal function
Chellappa, Sarah Laxhmi ULg; Ly, Julien; Gaggioni, Giulia et al

Conference (2014, June 16)

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See detailLight modulation of human sleep depends on a polymorphism in the clock gene PER3
Chellappa, Sarah Laxhmi ULg; Viola, Antoine; Schmidt, Christina ULg et al

in Behavioural Brain Research (2014), 271

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See detailLight modulation of human sleep depends on a polymorphism in the clock gene Period3.
Chellappa, Sarah Laxhmi ULg; Viola, Antoine U.; Schmidt, Christina ULg et al

in Behavioural brain research (2014), 271

Non-image-forming (NIF) responses to light powerfully modulate human physiology. However, it remains scarcely understood how NIF responses to light modulate human sleep and its EEG hallmarks, and if there ... [more ▼]

Non-image-forming (NIF) responses to light powerfully modulate human physiology. However, it remains scarcely understood how NIF responses to light modulate human sleep and its EEG hallmarks, and if there are differences across individuals. Here we investigated NIF responses to light on sleep in individuals genotyped for the PERIOD3 (PER3) variable-number tandem-repeat (VNTR) polymorphism. Eighteen healthy young men (20-28 years; mean+/-SEM: 25.9+/-1.2) homozygous for the PER3 polymorphism were matched by age, body-mass index, and ethnicity. The study protocol comprised a balanced cross-over design during the winter, during which participants were exposed to either light of 40lx at 6500K (blue-enriched) or light at 2500K (non-blue enriched), during 2h in the evening. Compared to light at 2500K, light at 6500K induced a significant increase in all-night NREM sleep slow-wave activity (SWA: 1.0-4.5Hz) in the occipital cortex for PER3(5/5) individuals, but not for PER3(4/4) volunteers. Dynamics of SWA across sleep cycles revealed increased occipital NREM sleep SWA for virtuallyall sleep episode only for PER3(5/5) individuals. Furthermore, they experienced light at 6500K as significantly brighter. Intriguingly, this subjective perception of brightness significantly predicted their increased occipital SWA throughout the sleep episode. Our data indicate that humans homozygous for the PER3(5/5) allele are more sensitive to NIF light effects, as indexed by specific changes in sleep EEG activity. Ultimately, individual differences in NIF light responses on sleep may depend on a clock gene polymorphism involved in sleep-wake regulation. [less ▲]

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See detailPrior light history impacts on cognitive brain function
Chellappa, Sarah Laxhmi ULg; Ly, Julien; Meyer, Christelle ULg et al

Conference (2014)

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See detailPrior light history impacts on higher order cognitive brain function
Chellappa, Sarah Laxhmi ULg; Ly, Julien; Meyer, Christelle ULg et al

Conference (2014)

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See detailCortical excitability depends on time awake and circadian phase
Ly, Julien; Gaggioni, Giulia; Chellappa, Sarah Laxhmi ULg et al

Conference (2014)

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See detailPhotic memory for executive brain responses
Chellappa*, Sarah Laxhmi ULg; Ly*, Julien ULg; Meyer, Christelle ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2014), Epub ahead of print

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See detailUltradian and circadian modulation of dream recall: EEG correlates and age effects
Chellappa, Sarah Laxhmi ULg; Cajochen, Christian

in International Journal of Psychophysiology (2013)

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See detailEffects of Artificial Dawn and Morning Blue Light on Daytime Cognitive Performance, Well-being, Cortisol and Melatonin Levels.
Gabel, Virginie; Maire, Micheline; Reichert, Carolin F. et al

in Chronobiology International (2013), 30(8), 988-97

Light exposure elicits numerous effects on human physiology and behavior, such as better cognitive performance and mood. Here we investigated the role of morning light exposure as a countermeasure for ... [more ▼]

Light exposure elicits numerous effects on human physiology and behavior, such as better cognitive performance and mood. Here we investigated the role of morning light exposure as a countermeasure for impaired cognitive performance and mood under sleep restriction (SR). Seventeen participants took part of a 48h laboratory protocol, during which three different light settings (separated by 2 wks) were administered each morning after two 6-h sleep restriction nights: a blue monochromatic LED (light-emitting diode) light condition (BL; 100 lux at 470 nm for 20 min) starting 2 h after scheduled wake-up time, a dawn-simulating light (DsL) starting 30 min before and ending 20 min after scheduled wake-up time (polychromatic light gradually increasing from 0 to 250 lux), and a dim light (DL) condition for 2 h beginning upon scheduled wake time (<8 lux). Cognitive tasks were performed every 2 h during scheduled wakefulness, and questionnaires were administered hourly to assess subjective sleepiness, mood, and well-being. Salivary melatonin and cortisol were collected throughout scheduled wakefulness in regular intervals, and the effects on melatonin were measured after only one light pulse. Following the first SR, analysis of the time course of cognitive performance during scheduled wakefulness indicated a decrease following DL, whereas it remained stable following BL and significantly improved after DsL. Cognitive performance levels during the second day after SR were not significantly affected by the different light conditions. However, after both SR nights, mood and well-being were significantly enhanced after exposure to morning DsL compared with DL and BL. Melatonin onset occurred earlier after morning BL exposure, than after morning DsL and DL, whereas salivary cortisol levels were higher at wake-up time after DsL compared with BL and DL. Our data indicate that exposure to an artificial morning dawn simulation light improves subjective well-being, mood, and cognitive performance, as compared with DL and BL, with minimal impact on circadian phase. Thus, DsL may provide an effective strategy for enhancing cognitive performance, well-being, and mood under mild sleep restriction. [less ▲]

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See detailAcute exposure to evening blue-enriched light impacts on human sleep
Chellappa, Sarah Laxhmi ULg; Steiner, Roland; Oelhafen, Peter et al

in Journal of Sleep Research (2013)

Detailed reference viewed: 3 (0 ULg)