101
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Jasinska M, Jasek-Gajda E, Woznicka O, Lis GJ, Pyza E, Litwin JA. Circadian clock regulates the shape and content of dendritic spines in mouse barrel cortex. PLoS One 2019; 14:e0225394. [PMID: 31730670 PMCID: PMC6857954 DOI: 10.1371/journal.pone.0225394] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/02/2019] [Indexed: 01/01/2023] Open
Abstract
Circadian rhythmicity affects neuronal activity induced changes in the density of synaptic contacts and dendritic spines, the most common location of synapses, in mouse somatosensory cortex. In the present study we analyzed morphology of single- and double-synapse spines under light/dark (12:12) and constant darkness conditions. Using serial electron micrographs we examined the shape of spines (stubby, thin, mushroom) and their content (smooth endoplasmic reticulum, spine apparatus), because these features are related to the maturation and stabilization of spines. We observed significant diurnal and circadian changes in the shape of spines that are differentially regulated: single-synapse spines remain under circadian clock regulation, while changes of double-synapse spines are driven by light. The thin and mushroom single-synapse spines, regardless of their content, are more stable comparing with the stubby single-synapse spines that show the greatest diversity. All types of double-synapse spines demonstrate a similar level of stability. In light/dark regime, formation of new mushroom single-synapse spines occurs, while under constant darkness new stubby single-synapse spines are formed. There are no shape preferences for new double-synapse spines. Diurnal and circadian alterations also concern spine content: both light exposure and the clock influence translocation of smooth endoplasmic reticulum from dendritic shaft to the spine. The increasing number of mushroom single-synapse spines and the presence of only those mushroom double-synapse spines that contain spine apparatus in the light phase indicates that the exposure to light, a stress factor for nocturnal animals, promotes enlargement and maturation of spines to increase synaptic strength and to enhance the effectiveness of neurotransmission.
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Affiliation(s)
- Malgorzata Jasinska
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
- * E-mail:
| | - Ewa Jasek-Gajda
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
| | - Olga Woznicka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Grzegorz J. Lis
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Jan A. Litwin
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
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Abstract
Artificial light at night (ALAN) is increasing exponentially worldwide, accelerated by the transition to new efficient lighting technologies. However, ALAN and resulting light pollution can cause unintended physiological consequences. In vertebrates, production of melatonin—the “hormone of darkness” and a key player in circadian regulation—can be suppressed by ALAN. In this paper, we provide an overview of research on melatonin and ALAN in vertebrates. We discuss how ALAN disrupts natural photic environments, its effect on melatonin and circadian rhythms, and different photoreceptor systems across vertebrate taxa. We then present the results of a systematic review in which we identified studies on melatonin under typical light-polluted conditions in fishes, amphibians, reptiles, birds, and mammals, including humans. Melatonin is suppressed by extremely low light intensities in many vertebrates, ranging from 0.01–0.03 lx for fishes and rodents to 6 lx for sensitive humans. Even lower, wavelength-dependent intensities are implied by some studies and require rigorous testing in ecological contexts. In many studies, melatonin suppression occurs at the minimum light levels tested, and, in better-studied groups, melatonin suppression is reported to occur at lower light levels. We identify major research gaps and conclude that, for most groups, crucial information is lacking. No studies were identified for amphibians and reptiles and long-term impacts of low-level ALAN exposure are unknown. Given the high sensitivity of vertebrate melatonin production to ALAN and the paucity of available information, it is crucial to research impacts of ALAN further in order to inform effective mitigation strategies for human health and the wellbeing and fitness of vertebrates in natural ecosystems.
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103
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Yasukouchi A, Maeda T, Hara K, Furuune H. Non-visual effects of diurnal exposure to an artificial skylight, including nocturnal melatonin suppression. J Physiol Anthropol 2019; 38:10. [PMID: 31462321 PMCID: PMC6714349 DOI: 10.1186/s40101-019-0203-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 08/19/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Recently, more consideration is being given to the beneficial effects of lighting on the maintenance and promotion of the health and well-being of office occupants in built environments. A new lighting technology using Rayleigh scattering has made it possible to simulate a blue sky. However, to date, no studies have examined the possible beneficial effects of such artificial skylights. The aims of this study were to examine the non-visual effects of artificial skylights and conventional fluorescent lights in a simulated office environment and to clarify the feature effects of the artificial skylights. METHODS Participants were 10 healthy male adults. Non-visual effects were evaluated based on brain arousal levels (α-wave ratio and contingent negative variation [CNV]), autonomic nervous activity (heart rate variability [HRV]), work performance, and subjective responses during daytime exposure to either an artificial skylight or fluorescent lights, as well as nocturnal melatonin secretion. RESULTS Subjective evaluations of both room lighting-related "natural" and "attractive" items and the "connected to nature" item were significantly higher with the skylight than with the fluorescent lights. Cortical arousal levels obtained from the early component of the CNV amplitude were significantly lower with the skylight than with the fluorescent lights, whereas α-wave ratio and work performance were similar between the two light sources. The HRV evaluation showed that sympathetic nerve tone was lower and parasympathetic nerve tone was higher, both significantly, for the skylight than for the fluorescent lights during daytime. Nocturnal melatonin secretion was significantly greater before and during light exposure at night under the daytime skylight than under the fluorescent lights. CONCLUSIONS Our results suggest that artificial skylights have some advantages over conventional fluorescent lights in maintaining ordinary work performance during daytime with less psychological and physiological stress. The findings also suggest that the artificial skylights would enable built environments to maintain long-term comfort and productivity.
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Affiliation(s)
- Akira Yasukouchi
- Department of Human Science, Faculty of Design, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan.
| | - Takafumi Maeda
- Department of Human Science, Faculty of Design, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan
| | - Kazuyoshi Hara
- La Forêt Engineering Co., Ltd, Roppongi Annex 7F, 6-7-6, Roppongi, Minato-ku, Tokyo, 106-0032, Japan
| | - Hiroyuki Furuune
- La Forêt Engineering Co., Ltd, Roppongi Annex 7F, 6-7-6, Roppongi, Minato-ku, Tokyo, 106-0032, Japan
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104
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Engelhard MM, Kollins SH. The Many Channels of Screen Media Technology in ADHD: a Paradigm for Quantifying Distinct Risks and Potential Benefits. Curr Psychiatry Rep 2019; 21:90. [PMID: 31410653 DOI: 10.1007/s11920-019-1077-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW Individuals with attention-deficit hyperactivity disorder (ADHD) may be unusually sensitive to screen media technology (SMT), from television to mobile devices. Although an association between ADHD and SMT use has been confirmed, its importance is uncertain partly due to variability in the way SMT has been conceptualized and measured. Here, we identify distinct, quantifiable dimensions of SMT use and review possible links to ADHD to facilitate more precise, reproducible investigation. RECENT FINDINGS Display characteristics, media multitasking, device notifications, SMT addiction, and media content all may uniquely impact the ADHD phenotype. Each can be investigated with a digital health approach and counteracted with device-based interventions. Novel digital therapeutics for ADHD demonstrate that specific forms of SMT can also have positive effects. Further study should quantify how distinct dimensions of SMT use relate to ADHD. SMT devices themselves can serve as a self-monitoring study platform and deliver digital interventions.
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Affiliation(s)
- Matthew M Engelhard
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Lakeview Pavilion, Suite 300, 2608 Erwin Rd, Durham, NC, 27705, USA.
| | - Scott H Kollins
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Lakeview Pavilion, Suite 300, 2608 Erwin Rd, Durham, NC, 27705, USA
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105
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Kazemi R, Alighanbari N, Zamanian Z. The effects of screen light filtering software on cognitive performance and sleep among night workers. Health Promot Perspect 2019; 9:233-240. [PMID: 31508344 PMCID: PMC6717920 DOI: 10.15171/hpp.2019.32] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/26/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Previous studies have reported impaired performance, sleepiness and sleep deprivation among night workers. The purpose of this study was to investigate the effect of color screen Light Filtering software on cognitive performance, alertness and sleep quality among night shift operators of a medical emergency operations center. Methods: This field trial interventional study was carried out among 30 nightshift operators of shiraz emergency control center. The baseline assessments were carried out under the existing computer screen light conditions in the week preceding the installation of f.lux software. The same measurements were repeated again 4 weeks after installing the software. The cognitive performance of the participants was measured using continuous performance test (CPT) and n-back, while their sleep quality was assessed through Pietersburg Sleep Quality Index (PSQI). Further, to assess their subjective and objective alertness, Stanford sleepiness index and go/nogo test were used, respectively. Results: The results of this study showed that Screen Light Filtering software significantly increased subjective (P<0.001) and objective alertness (P<0.05). Additionally, the performance of the working memory (P=0.008) and sleep quality (P=0.008) improved significantly after the intervention. Conclusion: The results revealed that using Screen Light Filtering software is an effective and low-cost method to improve sleep quality and cognitive performance since it filters the short wavelength part of the spectrum and helps body adaptation.
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Affiliation(s)
- Reza Kazemi
- Ergonomics Department, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Negar Alighanbari
- School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Zamanian
- Ergonomics Department, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
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106
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Lok R, van Koningsveld MJ, Gordijn MCM, Beersma DGM, Hut RA. Daytime melatonin and light independently affect human alertness and body temperature. J Pineal Res 2019; 67:e12583. [PMID: 31033013 PMCID: PMC6767594 DOI: 10.1111/jpi.12583] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/17/2019] [Accepted: 04/19/2019] [Indexed: 12/01/2022]
Abstract
Light significantly improves alertness during the night (Cajochen, Sleep Med Rev, 11, 2007 and 453; Ruger et al., AJP Regul Integr Comp Physiol, 290, 2005 and R1413), but results are less conclusive at daytime (Lok et al., J Biol Rhythms, 33, 2018 and 589). Melatonin and core body temperature levels at those times of day may contribute to differences in alerting effects of light. In this experiment, the combined effect of daytime exogenous melatonin administration and light intensity on alertness, body temperature, and skin temperature was studied. The goal was to assess whether (a) alerting effects of light are melatonin dependent, (b) soporific effects of melatonin are mediated via the thermoregulatory system, and (c) light can improve alertness after melatonin-induced sleepiness during daytime. 10 subjects (5 females, 5 males) received melatonin (5 mg) in dim (10 lux) and, on a separate occasion, in bright polychromatic white light (2000 lux). In addition, they received placebo both under dim and bright light conditions. Subjects participated in all four conditions in a balanced order, yielding a balanced within-subject design, lasting from noon to 04:00 pm. Alertness and performance were assessed half hourly, while body temperature and skin temperature were measured continuously. Saliva samples to detect melatonin concentrations were collected half hourly. Melatonin administration increased melatonin concentrations in all subjects. Subjective sleepiness and distal skin temperature increased after melatonin ingestion. Bright light exposure after melatonin administration did not change subjective alertness scores, but body temperature and proximal skin temperature increased, while distal skin temperature decreased. Light exposure did not significantly affect these parameters in the placebo condition. These results indicate that (a) exogenous melatonin administration during daytime increases subjective sleepiness, confirming a role for melatonin in sleepiness regulation, (b) bright light exposure after melatonin ingestion significantly affected thermoregulatory parameters without altering subjective sleepiness, therefore temperature changes seem nonessential for melatonin-induced sleepiness, (c) subjective sleepiness was increased by melatonin ingestion, but bright light administration was not able to improve melatonin-induced sleepiness feelings nor performance. Other (physiological) factors may therefore contribute to differences in alerting effects of light during daytime and nighttime.
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Affiliation(s)
- Renske Lok
- Chronobiology Unit, Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Minke J. van Koningsveld
- Chronobiology Unit, Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Marijke C. M. Gordijn
- Chronobiology Unit, Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
- Chrono@WorkGroningenThe Netherlands
| | - Domien G. M. Beersma
- Chronobiology Unit, Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Roelof A. Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
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107
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Rupp AC, Ren M, Altimus CM, Fernandez DC, Richardson M, Turek F, Hattar S, Schmidt TM. Distinct ipRGC subpopulations mediate light's acute and circadian effects on body temperature and sleep. eLife 2019; 8:e44358. [PMID: 31333190 PMCID: PMC6650245 DOI: 10.7554/elife.44358] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 06/18/2019] [Indexed: 12/16/2022] Open
Abstract
The light environment greatly impacts human alertness, mood, and cognition by both acute regulation of physiology and indirect alignment of circadian rhythms. These processes require the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), but the relevant downstream brain areas involved remain elusive. ipRGCs project widely in the brain, including to the central circadian pacemaker, the suprachiasmatic nucleus (SCN). Here we show that body temperature and sleep responses to acute light exposure are absent after genetic ablation of all ipRGCs except a subpopulation that projects to the SCN. Furthermore, by chemogenetic activation of the ipRGCs that avoid the SCN, we show that these cells are sufficient for acute changes in body temperature. Our results challenge the idea that the SCN is a major relay for the acute effects of light on non-image forming behaviors and identify the sensory cells that initiate light's profound effects on body temperature and sleep.
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Affiliation(s)
- Alan C Rupp
- Department of BiologyJohns Hopkins UniversityBaltimoreUnited States
| | - Michelle Ren
- Department of NeurobiologyNorthwestern UniversityEvanstonUnited States
| | - Cara M Altimus
- Department of BiologyJohns Hopkins UniversityBaltimoreUnited States
| | | | | | - Fred Turek
- Department of NeurobiologyNorthwestern UniversityEvanstonUnited States
| | - Samer Hattar
- Department of BiologyJohns Hopkins UniversityBaltimoreUnited States
- Department of NeuroscienceJohns Hopkins UniversityBaltimoreUnited States
| | - Tiffany M Schmidt
- Department of NeurobiologyNorthwestern UniversityEvanstonUnited States
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108
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de Zeeuw J, Papakonstantinou A, Nowozin C, Stotz S, Zaleska M, Hädel S, Bes F, Münch M, Kunz D. Living in Biological Darkness: Objective Sleepiness and the Pupillary Light Responses Are Affected by Different Metameric Lighting Conditions during Daytime. J Biol Rhythms 2019; 34:410-431. [PMID: 31156018 PMCID: PMC6637815 DOI: 10.1177/0748730419847845] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nighttime melatonin suppression is the most commonly used method to indirectly quantify acute nonvisual light effects. Since light is the principal zeitgeber in humans, there is a need to assess its strength during daytime as well. This is especially important since humans evolved under natural daylight but now often spend their time indoors under artificial light, resulting in a different quality and quantity of light. We tested whether the pupillary light response (PLR) could be used as a marker for nonvisual light effects during daytime. We also recorded the wake electroencephalogram to objectively determine changes in daytime sleepiness between different illuminance levels and/or spectral compositions of light. In total, 72 participants visited the laboratory 4 times for 3-h light exposures. All participants underwent a dim-light condition and either 3 metameric daytime light exposures with different spectral compositions of polychromatic white light (100 photopic lux, peak wavelengths at 435 nm or 480 nm, enriched with longer wavelengths of light) or 3 different illuminances (200, 600, and 1200 photopic lux) with 1 metameric lighting condition (peak wavelength at 435 nm or 480 nm; 24 participants each). The results show that the PLR was sensitive to both spectral differences between metameric lighting conditions and different illuminances in a dose-responsive manner, depending on melanopic irradiance. Objective sleepiness was significantly reduced, depending on melanopic irradiance, at low illuminance (100 lux) and showed fewer differences at higher illuminance. Since many people are exposed to such low illuminance for most of their day—living in biological darkness—our results imply that optimizing the light spectrum could be important to improve daytime alertness. Our results suggest the PLR as a noninvasive physiological marker for ambient light exposure effects during daytime. These findings may be applied to assess light-dependent zeitgeber strength and evaluate lighting improvements at workplaces, schools, hospitals, and homes.
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Affiliation(s)
- Jan de Zeeuw
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,Intellux GmbH, Berlin, Germany
| | - Alexandra Papakonstantinou
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin
| | - Claudia Nowozin
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin
| | - Sophia Stotz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin
| | | | - Sven Hädel
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology
| | - Frederik Bes
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin
| | - Mirjam Münch
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Immunology, Laboratory of Chronobiology.,Sleep/Wake Research Centre, Massey University, Wellington, New Zealand
| | - Dieter Kunz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Sleep Research & Clinical Chronobiology.,Intellux GmbH, Berlin, Germany.,St. Hedwig-Hospital, Clinic for Sleep & Chronomedicine, Berlin
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109
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Prayag AS, Najjar RP, Gronfier C. Melatonin suppression is exquisitely sensitive to light and primarily driven by melanopsin in humans. J Pineal Res 2019; 66:e12562. [PMID: 30697806 DOI: 10.1111/jpi.12562] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/01/2019] [Accepted: 01/19/2019] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Light elicits a range of non-visual responses in humans. Driven predominantly by intrinsically photosensitive retinal ganglion cells (ipRGCs), but also by rods and/or cones, these responses include melatonin suppression. A sigmoidal relationship has been established between melatonin suppression and light intensity; however, photoreceptoral involvement remains unclear. METHODS AND RESULTS In this study, we first modelled the relationships between alpha-opic illuminances and melatonin suppression using an extensive dataset by Brainard and colleagues. Our results show that (a) melatonin suppression is better predicted by melanopic illuminance compared to other alpha-opic illuminances, (b) melatonin suppression is predicted to occur at levels as low as ~1.5 melanopic lux (melanopsin-weighted irradiance 0.2 µW/cm2 ), (c) saturation occurs at 305 melanopic lux (melanopsin-weighted irradiance 36.6 µW/cm2 ). We then tested this melanopsin-weighted illuminance-response model derived from Brainard and colleagues' data and show that it predicts equally well melatonin suppression data from our laboratory, although obtained using different intensities and exposure duration. DISCUSSION Together, our findings suggest that melatonin suppression by monochromatic lights is predominantly driven by melanopsin and that it can be initiated at extremely low melanopic lux levels in experimental conditions. This emphasizes the concern of the non-visual impacts of low light intensities in lighting design and light-emitting devices.
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Affiliation(s)
- Abhishek S Prayag
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
| | - Raymond P Najjar
- Department of Visual Neuroscience, Singapore Eye Research Institute, Singapore
- The Ophthalmology & Visual Sciences ACP, Duke-NUS Medical School, Singapore
| | - Claude Gronfier
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
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110
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Zubidat AE, Fares B, Fares F, Haim A. Artificial Light at Night of Different Spectral Compositions Differentially Affects Tumor Growth in Mice: Interaction With Melatonin and Epigenetic Pathways. Cancer Control 2019; 25:1073274818812908. [PMID: 30477310 PMCID: PMC6259078 DOI: 10.1177/1073274818812908] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Lighting technology is rapidly advancing toward shorter wavelength illuminations
that offer energy-efficient properties. Along with this advantage, the increased
use of such illuminations also poses some health challenges, particularly breast
cancer progression. Here, we evaluated the effects of artificial light at night
(ALAN) of 4 different spectral compositions (500-595 nm) at 350 Lux on melatonin
suppression by measuring its urine metabolite 6-sulfatoxymelatonin, global DNA
methylation, tumor growth, metastases formation, and urinary corticosterone
levels in 4T1 breast cancer cell-inoculated female BALB/c mice. The results
revealed an inverse dose-dependent relationship between wavelength and melatonin
suppression. Short wavelength increased tumor growth, promoted lung metastases
formation, and advanced DNA hypomethylation, while long wavelength lessened
these effects. Melatonin treatment counteracted these effects and resulted in
reduced cancer burden. The wavelength suppression threshold for
melatonin-induced tumor growth was 500 nm. These results suggest that short
wavelength increases cancer burden by inducing aberrant DNA methylation mediated
by the suppression of melatonin. Additionally, melatonin suppression and global
DNA methylation are suggested as promising biomarkers for early diagnosis and
therapy of breast cancer. Finally, ALAN may manifest other physiological
responses such as stress responses that may challenge the survival fitness of
the animal under natural environments.
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Affiliation(s)
- A E Zubidat
- 1 The Israeli Center for Interdisciplinary Research in Chronobiology, University of Haifa, Haifa, Israel
| | - B Fares
- 2 Department of Human Biology, University of Haifa, Haifa, Israel.,3 Department of Molecular Genetics, Carmel Medical Center, Haifa, Israel
| | - F Fares
- 2 Department of Human Biology, University of Haifa, Haifa, Israel.,3 Department of Molecular Genetics, Carmel Medical Center, Haifa, Israel
| | - A Haim
- 1 The Israeli Center for Interdisciplinary Research in Chronobiology, University of Haifa, Haifa, Israel
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111
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Tonetti L, Natale V. Effects of a single short exposure to blue light on cognitive performance. Chronobiol Int 2019; 36:725-732. [PMID: 30897969 DOI: 10.1080/07420528.2019.1593191] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of the present study is to explore the effects of a single short one-minute exposure to blue light on cognitive performance. For this purpose, 32 young adults (16 females, mean age 24.06 ± 1.88 years) took part in a within-subjects research design, under two conditions: blue light and no light. Under both conditions, they performed the lexical decision task (LDT) in order to assess the degree of automatic activation of semantic memory through an embedded semantic priming (reaction times to prime - reaction times to target), together with the Attention Network Test (ANT) to assess the efficiency of the alerting, executive and orienting networks. During the LDT, a significantly stronger semantic priming under the blue light condition compared to no light was observed, while during the ANT a significant difference in orienting network efficiency between conditions was observed. The present data appear to highlight that even a single short exposure to blue light has an effect on cognitive performance in young adults.
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Affiliation(s)
- Lorenzo Tonetti
- a Department of Psychology , University of Bologna , Bologna , Italy
| | - Vincenzo Natale
- a Department of Psychology , University of Bologna , Bologna , Italy
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112
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Abstract
Dynamic vision is crucial to not only animals’ hunting behaviors but also human activities, and yet little is known about how to enhance it, except for extensive trainings like athletics do. Exposure to blue light has been shown to enhance human alertness (Chellappa et al., 2011), perhaps through intrinsically photosensitive retinal ganglion cells (ipRGCs), which are sensitive to motion perception as revealed by animal studies. However, it remains unknown whether blue light can enhance human dynamic vision, a motion-related ability. We conducted five experiments under blue or orange light to test three important components of dynamic vision: eye pursuit accuracy (EPA, Experiment 1), kinetic visual acuity (KVA, Experiment 1 and 2), and dynamic visual acuity (DVA, Experiment 3–5). EPA was measured by the distance between the position of the fixation and the position of the target when participants tracked a target dot. In the KVA task, participants reported three central target numbers (randomly chosen from 0 to 9) moving toward participants in the depth plane, with speed threshold calculated by a staircase procedure. In the DVA task, three numbers were presented along the meridian line on the same depth plane, with motion direction (Experiment 3) and difficulty level (Experiment 4) manipulated, and a blue light filter lens was used to test the ipRGCs contribution (Experiment 5). Results showed that blue light enhanced EPA and DVA, but reduced KVA. Further, DVA enhancement was modulated by difficulty level: blue light enhancement effect was found only with hard task in the downward motion in Experiment 3 and with the low contrast target in Experiment 4. However, this blue light enhancement effect was not caused by mechanism of the ipRGCs, at least not in the range we tested. In this first study demonstrating the relationship between different components of dynamic vision and blue light, our findings that DVA can be enhanced under blue light with hard but not easy task indicate that blue light can enhance dynamic visual discrimination when needed.
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Affiliation(s)
- Hung-Wen Chen
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Su-Ling Yeh
- Department of Psychology, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.,Center for Artificial Intelligence and Advanced Robotics, National Taiwan University, Taipei, Taiwan
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113
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Prayag AS, Jost S, Avouac P, Dumortier D, Gronfier C. Dynamics of Non-visual Responses in Humans: As Fast as Lightning? Front Neurosci 2019; 13:126. [PMID: 30890907 PMCID: PMC6411922 DOI: 10.3389/fnins.2019.00126] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/04/2019] [Indexed: 12/22/2022] Open
Abstract
The eye drives non-visual (NV) responses to light, including circadian resetting, pupillary reflex and alerting effects. Initially thought to depend on melanopsin-expressing retinal ganglion cells (ipRGCs), classical photopigments play a modulatory role in some of these responses. As most studies have investigated only a limited number of NV functions, generally under conditions of relatively high light levels and long duration of exposure, whether NV functions share similar irradiance sensitivities and response dynamics during light exposure is unknown. We addressed this issue using light exposure paradigms spectrally and spatially tuned to target mainly cones or ipRGCs, and by measuring longitudinally (50 min) several NV responses in 28 men. We demonstrate that the response dynamics of NV functions are faster than previously thought. We find that the brain, the heart, and thermoregulation are activated within 1 to 5 min of light exposure. Further, we show that NV functions do not share the same response sensitivities. While the half-maximum response is only ∼48 s for the tonic pupil diameter, it is ∼12 min for EEG gamma activity. Most NV responses seem to be saturated by low light levels, as low as 90 melanopic lux. Our results also reveal that it is possible to maintain optimal visual performance while modulating NV responses. Our findings have real-life implications. On one hand, light therapy paradigms should be re-evaluated with lower intensities and shorter durations, with the potential of improving patients' compliance. On the other hand, the significant impact of low intensity and short duration light exposures on NV physiology should make us reconsider the potential health consequences of light exposure before bedtime, in particular on sleep and circadian physiology.
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Affiliation(s)
- Abhishek S Prayag
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Sophie Jost
- ENTPE, LGCB, Université de Lyon, Lyon, France
| | | | | | - Claude Gronfier
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
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114
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Awakening effects of blue-enriched morning light exposure on university students' physiological and subjective responses. Sci Rep 2019; 9:345. [PMID: 30674951 PMCID: PMC6344573 DOI: 10.1038/s41598-018-36791-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 11/23/2018] [Indexed: 02/06/2023] Open
Abstract
We investigated physiological and subjective responses to morning light exposure of commercially available LED lighting with different correlated colour temperatures to predict how LED-based smart lighting employed in future learning environments will impact students. The classical markers of the circadian system (melatonin and cortisol), as well as the subjective perception of sleepiness, mood, and visual comfort, were compared. Fifteen university students underwent an hour of morning light exposure to both warm (3,500 K) and blue-enriched (6,500 K) white lights at recommended illuminance levels for classrooms and lecture halls (500 lux). The decline of melatonin levels was significantly greater after the exposure to blue-enriched white light. Exposure to blue-enriched white light significantly improved subjective perception of alertness, mood, and visual comfort. With regard to cortisol, we did not find a significant difference in the cortisol decrement between the two light conditions. Our findings suggest that the sensitivity of physiological and subjective responses to white LED light is blue-shifted. These findings, extending the already known effects of short-wavelength light on human physiology, reveal interesting practical implications. Blue-enriched LED light seems to be a simple yet effective potential countermeasure for morning drowsiness and dozing off in class, particularly in schools with insufficient daylight.
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115
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Hanifin J, Lockley S, Cecil K, West K, Jablonski M, Warfield B, James M, Ayers M, Byrne B, Gerner E, Pineda C, Rollag M, Brainard G. Randomized trial of polychromatic blue-enriched light for circadian phase shifting, melatonin suppression, and alerting responses. Physiol Behav 2019; 198:57-66. [DOI: 10.1016/j.physbeh.2018.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/06/2018] [Accepted: 10/03/2018] [Indexed: 11/25/2022]
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116
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Caldwell JA, Caldwell JL, Thompson LA, Lieberman HR. Fatigue and its management in the workplace. Neurosci Biobehav Rev 2019; 96:272-289. [DOI: 10.1016/j.neubiorev.2018.10.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/04/2018] [Accepted: 10/31/2018] [Indexed: 01/01/2023]
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117
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Łaszewska K, Goroncy A, Weber P, Pracki T, Tafil-Klawe M. Influence of the Spectral Quality of Light on Daytime Alertness Levels in Humans. Adv Cogn Psychol 2018; 14:192-208. [PMID: 32509040 PMCID: PMC7263078 DOI: 10.5709/acp-0250-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Exposure to light is very important for human health. However, the characteristics of the light stimulus and the appropriate timing of such exposure are essential. Studies that have used monochromatic light exposure have shown no systematic patterns for the effects of blue light compared to longer wavelengths. Previous studies have shown that red light exposure increases objective and subjective measures of alertness at night without suppressing nocturnal melatonin or inducing circadian disruption. The present study investigated whether noon time exposure to red light would increase both objective and subjective measures of alertness such as those measured by EEG, cognitive-behavioral performance, and subjective sleepiness. The three lighting conditions were as follows: dim light (< 0.01 lux at cornea), blue light (465 nm, 72 μW/cm2), and red light (625 nm, 18 μW/cm2), both at 40 lux. The results of the EEG data showed an increase in theta power over time in dim light only. In red light, alpha power showed a decrease over time. The impact of red light was observed in the performance measures: The only significant effect was a deterioration in the continuous performance test after red light exposure. Subjective measures of alertness were not affected by light in either condition, in contrast to darkness, when subjects reported greater sleepiness than before. None of the changes in objective measures of alertness induced by red light exposure translated into subjective sleepiness at noon. Thus, we concluded that behavioral effects of light at noon are very limited at best.
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Affiliation(s)
- Kamila Łaszewska
- Department of Psychology, Faculty of Humanities, Nicolaus Copernicus University, Fosa Staromiejska 1a, 87-100 Toruń, Poland
| | - Agnieszka Goroncy
- Department of Mathematical Statistics and Data Analysis, Faculty of Mathematics and Computer Science, Nicolaus CopernicusUniversity, Chopina 12/18, 87-100 Toruń, Poland
| | - Piotr Weber
- Atomic and Optical Physics Division, Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics andMathematics, Gdańsk University of Technology, Narutowicza 11/12, 80- 233 Gdańsk, Poland
| | - Tadeusz Pracki
- Department of Human Physiology, Nicolaus Copernicus University Ludwik Rydygier Collegium Medicum in Bydgoszcz,Karłowicza 24, 85-092 Bydgoszcz, Poland
| | - Małgorzata Tafil-Klawe
- Department of Human Physiology, Nicolaus Copernicus University Ludwik Rydygier Collegium Medicum in Bydgoszcz,Karłowicza 24, 85-092 Bydgoszcz, Poland
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118
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Light modulates oscillatory alpha activity in the occipital cortex of totally visually blind individuals with intact non-image-forming photoreception. Sci Rep 2018; 8:16968. [PMID: 30446699 PMCID: PMC6240048 DOI: 10.1038/s41598-018-35400-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 09/07/2018] [Indexed: 11/08/2022] Open
Abstract
The discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs) marked a major shift in our understanding of how light information is processed by the mammalian brain. These ipRGCs influence multiple functions not directly related to image formation such as circadian resetting and entrainment, pupil constriction, enhancement of alertness, as well as the modulation of cognition. More recently, it was demonstrated that ipRGCs may also contribute to basic visual functions. The impact of ipRGCs on visual function, independently of image forming photoreceptors, remains difficult to isolate, however, particularly in humans. We previously showed that exposure to intense monochromatic blue light (465 nm) induced non-conscious light perception in a forced choice task in three rare totally visually blind individuals without detectable rod and cone function, but who retained non-image-forming responses to light, very likely via ipRGCs. The neural foundation of such light perception in the absence of conscious vision is unknown, however. In this study, we characterized the brain activity of these three participants using electroencephalography (EEG), and demonstrate that unconsciously perceived light triggers an early and reliable transient desynchronization (i.e. decreased power) of the alpha EEG rhythm (8–14 Hz) over the occipital cortex. These results provide compelling insight into how ipRGC may contribute to transient changes in ongoing brain activity. They suggest that occipital alpha rhythm synchrony, which is typically linked to the visual system, is modulated by ipRGCs photoreception; a process that may contribute to the non-conscious light perception in those blind individuals.
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119
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Krüger EL, Tamura C, Trento TW. Identifying relationships between daylight variables and human preferences in a climate chamber. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:1292-1302. [PMID: 30045509 DOI: 10.1016/j.scitotenv.2018.06.164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/02/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
Interactions between human beings and the built environment are mediated by physiological and psychological stimuli, which may interfere in the perception and satisfaction related to indoor comfort variables. The study aims to explore the relationship between daylighting features and possible impacts on humans in regards to lighting preferences. The influence of different daylighting configurations, glazed façade orientation and season of the year on lighting preferences in human beings was evaluated by means of tests in a rotating climate with monitoring of environmental variables, developed by the Karlsruhe Institute of Technology, Karlsruhe, Germany. The sample, n = 16, is composed of German male students (height SD = 1.80 m, SD = 0.06; body weight SD = 80 kg, SD = 8.9; and age SD = 24.9 years, SD = 3.6). Under controlled thermal conditions (PMV approx. ±0.5), participants remained in two office-like environments over 5 h (8:00 am to 1:00 pm - local time) three days in a row, for three seasons of the year, totaling nine days of data collection per participant. Definitions of glazed façade orientations for the experimental rounds were done by means of computer simulations. Objective variables were measured by spectroradiometers at desk height, with sensor h = ca. 0.90 m, and comfortmeters. Preferences of daylighting features was assessed by a questionnaire with Likert-scale alternatives, administered online at 8:50 am, 10:30 am and 12:30 pm. Objective and subjective data were analyzed statistically (Spearman's rho, rs), suggesting possible correlations between lighting preferences and objective variables, including: E (lx), CCT (K), DWl (nm) and the circadian metric acv (circadian action factor).
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Affiliation(s)
- Eduardo L Krüger
- Departamento de Construção Civil, Universidade Tecnológica Federal do Paraná, Curitiba, Brazil.
| | - Cintia Tamura
- Universidade Tecnológica Federal do Paraná, Curitiba, Brazil
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120
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Daneault V, Dumont M, Massé É, Forcier P, Boré A, Lina JM, Doyon J, Vandewalle G, Carrier J. Plasticity in the Sensitivity to Light in Aging: Decreased Non-visual Impact of Light on Cognitive Brain Activity in Older Individuals but No Impact of Lens Replacement. Front Physiol 2018; 9:1557. [PMID: 30459639 PMCID: PMC6232421 DOI: 10.3389/fphys.2018.01557] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/17/2018] [Indexed: 11/29/2022] Open
Abstract
Beyond its essential visual role, light, and particularly blue light, has numerous non-visual effects, including stimulating cognitive functions and alertness. Non-visual effects of light may decrease with aging and contribute to cognitive and sleepiness complaints in aging. However, both the brain and the eye profoundly change in aging. Whether the stimulating effects light on cognitive brain functions varies in aging and how ocular changes may be involved is not established. We compared the impact of blue and orange lights on non-visual cognitive brain activity in younger (23.6 ± 2.5 years), and older individuals with their natural lenses (NL; 66.7 ± 5.1 years) or with intraocular lens (IOL) replacement following cataract surgery (69.6 ± 4.9 years). Analyses reveal that blue light modulates executive brain responses in both young and older individuals. Light effects were, however, stronger in young individuals including in the hippocampus and frontal and cingular cortices. Light effects did not significantly differ between older-IOL and older-NL while regression analyses indicated that differential brain engagement was not underlying age-related differences in light effects. These findings show that, although its impact decreases, light can stimulate cognitive brain activity in aging. Since lens replacement did not affect light impact, the brain seems to adapt to the progressive decrease in retinal light exposure in aging.
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Affiliation(s)
- Véronique Daneault
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.,Department of Psychology, University of Montreal, Montreal, QC, Canada
| | - Marie Dumont
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.,Department of Psychiatry, University of Montreal, Montreal, QC, Canada
| | - Éric Massé
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada
| | - Pierre Forcier
- École d'Optométrie, University of Montreal, Montreal, QC, Canada
| | - Arnaud Boré
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada
| | - Jean-Marc Lina
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.,Génie Électrique, École de technologie supérieure, Montreal, QC, Canada.,Centre de Recherches Mathématiques, Université de Montréal, Montreal, QC, Canada
| | - Julien Doyon
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Department of Psychology, University of Montreal, Montreal, QC, Canada
| | - Gilles Vandewalle
- GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging, University of Liège, Liège, Belgium
| | - Julie Carrier
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.,Department of Psychology, University of Montreal, Montreal, QC, Canada
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121
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Kazemi R, Choobineh A, Taheri S, Rastipishe P. Comparing task performance, visual comfort and alertness under different lighting sources: an experimental study. EXCLI JOURNAL 2018; 17:1018-1029. [PMID: 30564081 PMCID: PMC6295624 DOI: 10.17179/excli2018-1676] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/16/2018] [Indexed: 11/10/2022]
Abstract
The aim of this study is to compare the effects of different light sources - namely light-emitting diode (LED), compact fluorescent (FLcomp) and fluorescent with warm color temperature (FLwarm) and cool color temperature (FLcool) - on the performances, alertness, visual comfort level and preferences in a pilot study. A laboratory controlled experiment was conducted by focusing on 20 postgraduate students who volunteered to participate in a series of tests under four different light sources. "GO NO GO" task and Karolinska Sleepiness Scale (KSS) were employed to assess objective and subjective alertness, while modified OLS questionnaire was used to gauge comfort level and preferences. In addition, editing and typing tasks were carried out as a performance evaluation. Significant increase was observed in subjective and objective alertness level under FLcool condition and LED in comparison to FLwarm and FLcomp (p < 0.05). In terms of typing performances, respondents performed significantly better with regard to typing speed under FLcool than FLwarm and FLcomp. The lowest number of typing errors was made under FLcool, followed by LED, FLcomp and FLwarm. LED was the most preferred (p=0.001) and most comfortable (p=0.011) lighting condition. The study concludes that the FLcool and LED were more beneficial for alertness level and performance for both computer-based and paper-based activities.
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Affiliation(s)
- Reza Kazemi
- Research Center for Health Science, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Ergonomics, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alireza Choobineh
- Research Center for Health Science, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Ergonomics, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Shirin Taheri
- Student Research Committee, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Pegah Rastipishe
- Student Research Committee, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
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122
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Effects of blue- and red-enriched light on attention and sleep in typically developing adolescents. Physiol Behav 2018; 199:11-19. [PMID: 30381244 DOI: 10.1016/j.physbeh.2018.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/15/2018] [Accepted: 10/26/2018] [Indexed: 11/22/2022]
Abstract
Differential effects of blue- and red-enriched light on attention and sleep have been primarily described in adults. In our cross-over study in typically developing adolescents (11-17 years old), we found attention enhancing effects of blue- compared to red-enriched light in the morning (high intensity of ca. 1000 lx, short duration: <1 h) in two of three attention tasks: e.g. better performance in math tests and reduced reaction time variability in a computerized attention test. In our pilot study, actigraphy measures of sleep indicated slight benefits for red- compared to blue-enriched light in the evening: tendencies toward a lower number of phases with movement activity after sleep onset in the complete sample and shorter sleep onset latency in a subgroup with later evening exposure times. These findings point to the relevance of light concepts regarding attention and sleep in typically developing adolescents. Such concepts should be developed and tested further in attention demanding contexts (at school) and for therapeutic purposes in adolescents with impaired attention or impaired circadian rhythms.
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123
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Kazemi R, Hemmatjo R, Mokarami H, Hamidreza M. The effect of a blue enriched white light on salivary antioxidant capacity and melatonin among night shift workers: a field study. Ann Occup Environ Med 2018; 30:61. [PMID: 30364378 PMCID: PMC6194576 DOI: 10.1186/s40557-018-0275-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/10/2018] [Indexed: 12/04/2022] Open
Abstract
Background Because of their positive impact on individuals’ performance and alertness, blue enriched white light sources are gaining popularity in households and industries. However, these sources of blue light spectrum may cause oxidative stress. On the other hand, there are no empirical studies investigating the negative effect of blue enriched white light on oxidative stress. Thus, the current study aimed at empirical assessment of the effect of such light sources on oxidative stress among night shift workers. Methods The study, which adopted a cross-sectional design, focused on 30 control room operators of a petrochemical complex. The subjects followed a shift-work schedule comprising 7 night shifts, 7 day shifts, and 7 days off. The subjects were exposed to 6500 K, 3000 K, and 17,000 K light sources (which have various degrees of blue light) during three consecutive work cycles, with each cycle lasting for 7 nights. In each light condition, three salivary measurements were conducted (at the beginning, in the middle, and at the end of the shift). The measurements were used to assess catalase (CAT), total thiol molecules (TTG), and total antioxidant capacity (TAC), and melatonin. Results The results of repeated measures ANOVA showed that there was no significant difference among various light conditions with regard to salivary biomarkers (catalase, total thiol molecules, and total antioxidant capacity). There was however a significant difference between 3000 K and 17,000 K conditions with regard to the concentration of salivary melatonin (p = 0.001). Conclusion Given that there was no significant difference among various light conditions in terms of biomarkers, it is concluded that using sources of light with high color temperature can be recommended. Nonetheless, because of the limitations of the present study (e.g. short period of intervention), it is suggested that care should be exercised in using such light sources.
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Affiliation(s)
- Reza Kazemi
- 1Research Center for Health Sciences, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran.,2Department of Ergonomics, School of Health, Shiraz University of Medical Sciences, Razi avenue, Shiraz, Iran
| | - Rasoul Hemmatjo
- 3Department of Occupational Health Engineering, School of Health, Urmia University of Medical Sciences, Urmia, Iran
| | | | - Mokarami Hamidreza
- 2Department of Ergonomics, School of Health, Shiraz University of Medical Sciences, Razi avenue, Shiraz, Iran
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124
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Tähkämö L, Partonen T, Pesonen AK. Systematic review of light exposure impact on human circadian rhythm. Chronobiol Int 2018; 36:151-170. [DOI: 10.1080/07420528.2018.1527773] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Leena Tähkämö
- Lighting Unit, Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Timo Partonen
- Mental Health Unit, Department of Public Health Solutions, National Institute for Health and Welfare (THL), Helsinki, Finland
| | - Anu-Katriina Pesonen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, University of Helsinki, Finland
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125
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Łaszewska K, Goroncy A, Weber P, Pracki T, Tafil-Klawe M, Pracka D, Złomańczuk P. Daytime Acute Non-Visual Alerting Response in Brain Activity Occurs as a Result of Short- and Long-Wavelengths of Light. J PSYCHOPHYSIOL 2018. [DOI: 10.1027/0269-8803/a000199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. Very recent preliminary findings concerning the alerting capacities of light stimulus with long-wavelengths suggest the existence of neural pathways other than melatonin suppression that trigger the nonvisual response. Though the nonvisual effects of light during the daytime have not been investigated thoroughly, they are definitely worth investigating. The purpose of the present study is to enrich existing evidence by describing how quantitative electroencephalography (EEG) signal analysis can give insight into the measurement of the acute nonvisual response observed in brain states generated during daytime exposure to light (when melatonin secretion is negligible). EEG changes were assessed in 19 subjects during the daytime while being exposed to both short- (blue, 72 μW/cm2) and long-wavelength (red, 18 μW/cm2) radiation. We showed that artificial light stimulus as low as 40 lux decreases the synchronization in the upper theta, lower alpha, and upper alpha EEG activity spectrum. The direction of change was consistent with an increased level of alertness. We can conclude that EEG analysis is an indicator of the acute nonvisual response to daytime light. Surprisingly, the response was more spread over the scalp during exposure to red light than to blue light. According to our study, the response to long-wavelength stimulus that inhibits sleepiness, thereby inducing alertness, also takes place at the bright part of the 24-hr day when human beings are naturally predisposed to be exposed to a high level of sunlight: between 12 and 4 PM. The absorption spectrum of the nonvisual system seems to have different characteristics than was previously suspected: it is not dominated by the short-wavelengths, but involves long-wavelengths. Since we observed the predominance of the red-light alerting effect over the blue-light in this experiment, we conclude that more than one mechanism, beyond the melatonin pathway, must be involved.
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Affiliation(s)
- Kamila Łaszewska
- Department of Physiology, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland
| | - Agnieszka Goroncy
- Department of Probability Theory and Stochastic Analysis, Faculty of Mathematics and Computer Science, Nicolaus Copernicus University, Toruń, Poland
| | - Piotr Weber
- Department of Atomic, Molecular and Optical Physics, Gdańsk University of Technology, Gdańsk, Poland
| | - Tadeusz Pracki
- Department of Physiology, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland
| | - Małgorzata Tafil-Klawe
- Department of Physiology, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland
| | - Daria Pracka
- Department of Physiology, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland
| | - Piotr Złomańczuk
- Department of Physiology, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland
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126
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Raikes AC, Killgore WDS. Potential for the development of light therapies in mild traumatic brain injury. Concussion 2018; 3:CNC57. [PMID: 30370058 PMCID: PMC6199671 DOI: 10.2217/cnc-2018-0006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022] Open
Abstract
Light affects almost all aspects of human physiological functioning, including circadian rhythms, sleep-wake regulation, alertness, cognition and mood. We review the existing relevant literature on the effects of various wavelengths of light on these major domains, particularly as they pertain to recovery from mild traumatic brain injuries. Evidence suggests that light, particularly in the blue wavelengths, has powerful alerting, cognitive and circadian phase shifting properties that could be useful for treatment. Other wavelengths, such as red and green may also have important effects that, if targeted appropriately, might also be useful for facilitating recovery. Despite the known effects of light, more research is needed. We recommend a personalized medicine approach to the use of light therapy as an adjunctive treatment for patients recovering from mild traumatic brain injury.
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Affiliation(s)
- Adam C Raikes
- Social, Cognitive & Affective Neuroscience Lab, Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, USA
- ORCID: 0000-0002-1609-6727
| | - William DS Killgore
- Social, Cognitive & Affective Neuroscience Lab, Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, USA
- ORCID: 0000-0002-5328-0208
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127
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Xu Q, Lang CP. Revisiting the alerting effect of light: A systematic review. Sleep Med Rev 2018; 41:39-49. [PMID: 29398582 DOI: 10.1016/j.smrv.2017.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 11/28/2017] [Accepted: 12/01/2017] [Indexed: 01/06/2023]
Abstract
Light plays an essential role in maintaining alertness levels. Like other non-image-forming responses, the alerting effect of light is influenced by its spectral wavelength, duration and intensity. Alertness levels are also dependent on circadian rhythm (process C) and homeostatic sleep pressure (process S), consistent with the classic two-process model of sleep regulation. Over the last decade, there has been increasing recognition of an additional process (referred to as the third process) in sleep regulation. This third process seems to receive sensory inputs from body systems such as digestion, and is usually synchronised with process C and process S. Previous studies on the alerting effect of light have been mostly conducted in laboratories. Although these studies are helpful in delineating the impact of process C and process S, their ability to assist in understanding the third process is limited. This systematic review investigated the factors that influence the alerting effect of light by examining randomised controlled trials and randomised or counterbalanced crossover studies. Factors that influence light's alerting effect were examined with reference to the three-process model. The post-illuminance alerting effect was examined separately due to its potential to offer flexible workplace-based light interventions to increase or maintain employees' alertness.
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Affiliation(s)
- Qunyan Xu
- School of Nursing and Midwifery, University of South Australia, Australia.
| | - Cathryne P Lang
- School of Psychology, Australian Catholic University, Australia
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128
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Hiwa S, Katayama T, Hiroyasu T. Functional near-infrared spectroscopy study of the neural correlates between auditory environments and intellectual work performance. Brain Behav 2018; 8:e01104. [PMID: 30183142 PMCID: PMC6192398 DOI: 10.1002/brb3.1104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 06/14/2018] [Accepted: 07/29/2018] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Many people spend a considerable amount of time performing intellectual activities within auditory environments that affect work efficiency. To investigate auditory environments that improve working efficiency, we investigated the relationship between brain activity and performance of the number memory task in environments with and without white noise using functional near-infrared spectroscopy (fNIRS). METHODS Twenty-nine healthy subjects (aged 21.9 ± 1.4 years) performed the number memory task in both the white noise and silent environments. Cerebral blood flow changes during the task were measured using an ETG-7100 fNIRS system (Hitachi, Ltd., Tokyo, Japan). The psychological states of the subjects were also estimated by subjective ratings of the pleasantness of the auditory environment. Then, they were divided into three groups based on their task scores. The differences in the cerebral blood flow (CBF) changes, functional connection strength, and the subjects' feelings of pleasantness to the noise between the subject groups were analyzed and discussed. RESULTS The first group felt that the white noise was pleasant, which strengthened the bilateral functional connections between the brain regions related to the memory task. Therefore, the subjects' task performance improved in the white noise environment. Although the second group felt that the white noise was uncomfortable, the frontal regions related to attention control were more activated in the white noise environment to sustain the task performance in the noisy environment. The third group felt that the white noise was unpleasant, and their CBF decreased in that environment, which was associated with deteriorated task performance. CONCLUSIONS Task performance was closely related to the subjects' feelings of pleasantness to the noise. The results of the analysis of the CBF changes and functional connectivity suggested that the effects of the white noise on brain activity differed among the three groups.
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129
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Lok R, Smolders KCHJ, Beersma DGM, de Kort YAW. Light, Alertness, and Alerting Effects of White Light: A Literature Overview. J Biol Rhythms 2018; 33:589-601. [PMID: 30191746 PMCID: PMC6236641 DOI: 10.1177/0748730418796443] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Light is known to elicit non-image-forming responses, such as effects on alertness. This has been reported especially during light exposure at night. Nighttime results might not be translatable to the day. This article aims to provide an overview of (1) neural mechanisms regulating alertness, (2) ways of measuring and quantifying alertness, and (3) the current literature specifically regarding effects of different intensities of white light on various measures and correlates of alertness during the daytime. In general, the present literature provides inconclusive results on alerting effects of the intensity of white light during daytime, particularly for objective measures and correlates of alertness. However, the various research paradigms employed in earlier studies differed substantially, and most studies tested only a limited set of lighting conditions. Therefore, the alerting potential of exposure to more intense white light should be investigated in a systematic, dose-dependent manner with multiple correlates of alertness and within one experimental paradigm over the course of day.
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Affiliation(s)
- Renske Lok
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Karin C H J Smolders
- Human-Technology Interaction, School of Innovation Sciences, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Domien G M Beersma
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Yvonne A W de Kort
- Human-Technology Interaction, School of Innovation Sciences, Eindhoven University of Technology, Eindhoven, the Netherlands
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130
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Lok R, Woelders T, Gordijn MCM, Hut RA, Beersma DGM. White Light During Daytime Does Not Improve Alertness in Well-rested Individuals. J Biol Rhythms 2018; 33:637-648. [PMID: 30191761 PMCID: PMC6236585 DOI: 10.1177/0748730418796036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Broad-spectrum light applied during the night has been shown to affect alertness in a
dose-dependent manner. The goal of this experiment was to investigate whether a similar
relationship could be established for light exposure during daytime. Fifty healthy
participants were subjected to a paradigm (0730-1730 h) in which they were intermittently
exposed to 1.5 h of dim light (<10 lux) and 1 h of experimental light (24-2000 lux).
The same intensity of experimental light was used throughout the day, resulting in groups
of 10 subjects per intensity. Alertness was assessed with subjective and multiple
objective measures. A significant effect of time of day was found in all parameters of
alertness (p < 0.05). Significant dose-response relationships between
light intensity and alertness during the day could be determined in a few of the
parameters of alertness at some times of the day; however, none survived correction for
multiple testing. We conclude that artificial light applied during daytime at intensities
up to 2000 lux does not elicit significant improvements in alertness in non-sleep-deprived
subjects.
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Affiliation(s)
- Renske Lok
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Tom Woelders
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Marijke C M Gordijn
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands.,Chrono@Work, Groningen, the Netherlands
| | - Roelof A Hut
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Domien G M Beersma
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
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131
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Hartstein LE, LeBourgeois MK, Berthier NE. Light correlated color temperature and task switching performance in preschool-age children: Preliminary insights. PLoS One 2018; 13:e0202973. [PMID: 30161180 PMCID: PMC6117001 DOI: 10.1371/journal.pone.0202973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 08/13/2018] [Indexed: 11/18/2022] Open
Abstract
Data from a growing number of experimental studies show that exposure to higher correlated color temperature (CCT) ambient light, containing more blue light, can positively impact alertness and cognitive performance in older children and adults. To date, few if any studies have examined whether light exposure influences cognitive task performance in preschool-age children, who are in the midst of rapid developmental changes in attention and executive function skills. In this study, healthy children aged 4.5-5.5 years (n = 20; 11 females) completed measures of sustained attention and task switching twice while being exposed to LED light set to either 3500K (a lower CCT) or 5000K (a higher CCT). A control group (n = 18; 10 females) completed the tasks twice under only the 3500K lighting condition. Although the lighting condition did not impact performance on the sustained attention task, exposure to the higher CCT light lead to greater improvement in preschool-age children's task switching performance (F(1,36) = 4.41, p = 0.04). Children in the control group showed a 6.5% increase in task switching accuracy between time points, whereas those in the experimental group improved by 15.2%. Our primary finding-that exposure to light at a higher correlated color temperature leads to greater improvement in task switching performance-indicates that the relationship between the spectral power distribution of light and executive function abilities is present early in cognitive development. These data have implications for designing learning environments and suggest that light may be an important contextual factor in the lives of young children in both the home and the classroom.
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Affiliation(s)
- Lauren E. Hartstein
- Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, MA, United States of America
- Lighting Enabled Systems & Applications Engineering Research Center, Rensselaer Polytechnic Institute, Troy, NY, United States of America
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States of America
- * E-mail:
| | - Monique K. LeBourgeois
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States of America
| | - Neil E. Berthier
- Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, MA, United States of America
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132
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Subjective time expansion with increased stimulation of intrinsically photosensitive retinal ganglion cells. Sci Rep 2018; 8:11693. [PMID: 30076316 PMCID: PMC6076248 DOI: 10.1038/s41598-018-29613-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 07/12/2018] [Indexed: 01/08/2023] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) contain photoreceptors that are especially sensitive to blue light. Nevertheless, how blue light and ipRGCs affect time perception remains unsolved. We used the oddball paradigm and manipulated the background light to examine whether and how blue light and ipRGCs affect perceived duration. In the oddball paradigm, participants were asked to judge the duration of the target (oddball), compared to that of the standard, with a two alternative-forced-choice procedure. When the background light was controlled to be either blue or red in Experiment 1, results showed that blue light led to longer subjective duration compared to red light. Experiment 2 further clarified the contribution of the ipRGCs. A set of multi-primary projector system that could manipulate the ipRGC stimulation were used, while the color and luminance of the background lights were kept constant throughout. Results showed that increased stimulation of ipRGCs under metameric background expanded subjective time. These results suggest that ipRGC stimulation increases arousal/attention so as to expand subjective duration.
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133
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Fatima M, Zafar H, Talha Sana M, Shafique M. Investigating the Effect of Different Wavelength of Light on Heart Rate Variability and Perfusion Index. 2018 2ND INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING (IBIOMED) 2018. [DOI: 10.1109/ibiomed.2018.8534794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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134
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Schmidt C, Xhrouet M, Hamacher M, Delloye E, LeGoff C, Cavalier E, Collette F, Vandewalle G. Light exposure via a head-mounted device suppresses melatonin and improves vigilant attention without affecting cortisol and comfort. Psych J 2018; 7:163-175. [PMID: 29943899 DOI: 10.1002/pchj.215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/03/2018] [Accepted: 04/08/2018] [Indexed: 11/11/2022]
Abstract
We aimed at assessing whether a head-mounted light therapy device, enriched in blue wavelengths, suppresses melatonin secretion and improves vigilant attention in the late evening hours. We also assessed whether using such light device is associated with discomfort and physiological stress. Seventeen healthy young participants (eight females) participated in a counterbalanced within-subject design during which they were exposed for 2 hr before habitual sleep time to a blue-enriched light (1500 lx) or to a lower intensity red-light (150 lx) control condition, using a new-generation light emitting diode (LED) head-mounted device. Compared to the red light control condition, blue-enriched light significantly reduced melatonin secretion and reaction times during a psychomotor vigilance task while no significant differences were detected in discomfort and cortisol levels. These results suggest that, compared to a control condition, blue-enriched light, delivered by a new-generation head-mounted device, elicits typical non-visual responses to light without detectable discomfort and physiological stress. They suggest that such devices might constitute an effective alternative to standard light boxes.
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Affiliation(s)
- Christina Schmidt
- Sleep Research Group, GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging Unit, University of Liège, Liège, Belgium.,Psychology and Neuroscience of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, Liège, Belgium
| | - Marine Xhrouet
- Sleep Research Group, GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging Unit, University of Liège, Liège, Belgium.,Psychology and Neuroscience of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, Liège, Belgium
| | - Manon Hamacher
- Sleep Research Group, GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging Unit, University of Liège, Liège, Belgium.,Psychology and Neuroscience of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, Liège, Belgium
| | | | - Caroline LeGoff
- Department of Clinical Chemistry, University Hospital of Liège, University of Liège, Liège, Belgium
| | - Etienne Cavalier
- Department of Clinical Chemistry, University Hospital of Liège, University of Liège, Liège, Belgium
| | - Fabienne Collette
- Sleep Research Group, GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging Unit, University of Liège, Liège, Belgium.,Psychology and Neuroscience of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, Liège, Belgium
| | - Gilles Vandewalle
- Sleep Research Group, GIGA-Institute, Cyclotron Research Centre-In Vivo Imaging Unit, University of Liège, Liège, Belgium
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135
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Richardson C, Micic G, Cain N, Bartel K, Maddock B, Gradisar M. Cognitive performance in adolescents with Delayed Sleep-Wake Phase Disorder: Treatment effects and a comparison with good sleepers. J Adolesc 2018; 65:72-84. [DOI: 10.1016/j.adolescence.2018.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 02/12/2018] [Accepted: 03/05/2018] [Indexed: 12/23/2022]
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136
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Russart KLG, Nelson RJ. Artificial light at night alters behavior in laboratory and wild animals. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:401-408. [PMID: 29806740 DOI: 10.1002/jez.2173] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022]
Abstract
Life has evolved to internalize and depend upon the daily and seasonal light cycles to synchronize physiology and behavior with environmental conditions. The nightscape has been vastly changed in response to the use of artificial lighting. Wildlife is now often exposed to direct lighting via streetlights or indirect lighting via sky glow at night. Because many activities rely on daily and seasonal light cues, the effects of artificial light at night could be extensive, but remain largely unknown. Laboratory studies suggest exposure to light at night can alter typical timing of daily locomotor activity and shift the timing of foraging/food intake to the daytime in nocturnal rodents. Additionally, nocturnal rodents decrease anxiety-like behaviors (i.e., spend more time in the open and increase rearing up) in response to even dim light at night. These are all likely maladaptive responses in the wild. Photoperiodic animals rely on seasonal changes in day length as a cue to evoke physiological and behavioral modifications to anticipate favorable and unfavorable conditions for survival and reproduction. Light at night can mask detection of short days, inappropriately signal long days, and thus desynchronize seasonal reproductive activities. We review laboratory and the sparse field studies that address the effects of exposure to artificial light at night to propose that exposure to light at night disrupts circadian and seasonal behavior in wildlife, which potentially decreases individual fitness and modifies ecosystems.
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Affiliation(s)
- Kathryn L G Russart
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Randy J Nelson
- Behavioral Medicine and Psychiatry, School of Medicine, West Virginia University, Morgantown, West Virginia
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137
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Rodríguez-Morilla B, Madrid JA, Molina E, Pérez-Navarro J, Correa Á. Blue-Enriched Light Enhances Alertness but Impairs Accurate Performance in Evening Chronotypes Driving in the Morning. Front Psychol 2018; 9:688. [PMID: 29867659 PMCID: PMC5962740 DOI: 10.3389/fpsyg.2018.00688] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/20/2018] [Indexed: 12/26/2022] Open
Abstract
Attention maintenance is highly demanding and typically leads to vigilance decrement along time on task. Therefore, performance in tasks involving vigilance maintenance for long periods, such as driving, tends to deteriorate over time. Cognitive performance has been demonstrated to fluctuate over 24 h of the day (known as circadian oscillations), thus showing peaks and troughs depending on the time of day (leading to optimal and suboptimal times of day, respectively). Consequently, vigilance decrements are more pronounced along time on task when it is performed at suboptimal times of day. According to research, light exposure (especially blue-enriched white) enhances alertness. Thus, it has been proposed to prevent the vigilance decrement under such adverse circumstances. We aimed to explore the effects of blue-enriched white light (vs. dim light) on the performance of a simulated driving task at a suboptimal time of day. A group of evening-types was tested at 8 am, as this chronotype had previously shown their largest vigilance decrement at that time. In the dim light condition, vigilance decrements were expected on both subjective (as increments in the Karolinska Sleepiness Scale scores) and behavioral measures [as slower reaction times (RTs) in the auditory Psychomotor Vigilance Task, slower RTs to unexpected events during driving, and deteriorated driving accuracy along time on task]. Physiological activation was expected to decrease (as indexed by an increase of the distal-proximal temperature gradient, DPG). Under blue-enriched white light, all these trends should be attenuated. Results from the control dim light condition replicated the vigilance decrement in all measures. Most important, the blue-enriched white light attenuated this decrement, leading to both lower DPG and faster RTs. However, it impaired accuracy of driving performance, and did not have any effect on subjective sleepiness. We conclude that exposure to blue-enriched light provides an effective countermeasure to enhance vigilance performance at suboptimal times of day, according to measures such as RTs. However, it should be considered that alerting effects of light could impair accuracy in precision tasks as keeping a proper car position. The current findings provide ergonomic implications for safety and fatigue related management systems.
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Affiliation(s)
| | - Juan A Madrid
- Chronobiology Laboratory, University of Murcia, Murcia, Spain
| | - Enrique Molina
- Centro de Investigación Mente, Cerebro y Comportamiento, University of Granada, Granada, Spain
| | | | - Ángel Correa
- Centro de Investigación Mente, Cerebro y Comportamiento, University of Granada, Granada, Spain
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138
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Schobersberger W, Blank C, Hanser F, Griesmacher A, Canazei M, Leichtfried V. Impact of a single, short morning bright light exposure on tryptophan pathways and visuo- and sensorimotor performance: a crossover study. J Physiol Anthropol 2018; 37:12. [PMID: 29685169 PMCID: PMC5913807 DOI: 10.1186/s40101-018-0173-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 04/16/2018] [Indexed: 11/29/2022] Open
Abstract
Background Bright light (BL) has been shown to be effective in enhancing both cognitive and physical performances. Alterations in nighttime melatonin levels have also been observed. However, evaluations of light-induced changes in the preceding biochemical processes are absent. Therefore, the impact of a single morning BL exposure on sensorimotor and visuomotor performance, as well as tryptophan (trp) and trp metabolites, was evaluated in this study. Methods In a crossover design, 33 healthy volunteers were randomly exposed to 30 min of < 150 lx at eye level (office light, OL) and 5000 lx at eye level (bright light, BL) of 6500 K in the morning hours. Trp, sulfatoxymelatonin (aMT6s), and kynurenine (kyn) courses over the morning hours were analyzed, and changes in sensori- and visuomotor measures were examined. Results Motoric performance increased in both setups, independent of light intensity. aMT6s and kyn decreased equally under both lighting conditions. Trp levels decreased from a mean (95% confidence interval) of 82.0 (77.2–86.9) to 66.5 (62.5–70.1) in the OL setup only. Conclusion These data suggest that BL in the morning hours has a limited effect on visuo- and sensorimotor performance. Nevertheless, trp degradation pathways in the morning show diverse courses after OL and BL exposure. This suggests that trp courses can potentially be altered by BL exposure.
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Affiliation(s)
- Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, UMIT - University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tyrol, Austria. .,Tirol Kliniken GmbH, Anichstraße 35, 6020, Innsbruck, Austria.
| | - Cornelia Blank
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, UMIT - University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tyrol, Austria
| | - Friedrich Hanser
- Department of Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT - University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tyrol, Austria
| | - Andrea Griesmacher
- Central Institute of Medical and Chemical Diagnostics, LKH - University Hospital of Innsbruck, Anichstraße 35, 6020, Innsbruck, Tyrol, Austria
| | - Markus Canazei
- Department of Visual Perception, Bartenbach GmbH, Rinner Strasse 14, 6071, Aldrans, Tyrol, Austria
| | - Veronika Leichtfried
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, UMIT - University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tyrol, Austria
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139
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Scheuermaier K, Münch M, Ronda JM, Duffy JF. Improved cognitive morning performance in healthy older adults following blue-enriched light exposure on the previous evening. Behav Brain Res 2018; 348:267-275. [PMID: 29684473 DOI: 10.1016/j.bbr.2018.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 04/03/2018] [Accepted: 04/15/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVES Exposure to light can have acute alerting and circadian phase-shifting effects. This study investigated the effects of evening exposure to blue-enriched polychromatic white (BEL) vs. polychromatic white light (WL) on sleep inertia dissipation the following morning in older adults. METHODS Ten healthy older adults (average age = 63.3 yrs; 6F) participated in a 13-day study comprising three baseline days, an initial circadian phase assessment, four days with 2-h evening light exposures, a post light exposure circadian phase assessment and three recovery days. Participants were randomized to either BEL or WL of the same irradiance for the four evening light exposures. On the next mornings at 2, 12, 22 and 32 min after each wake time, the participants completed a 90-s digit-symbol substitution test (DSST) to assess working memory, and objective alertness was assessed using a wake EEG recording. DSST and power density from the wake EEG recordings were compared between the two groups. RESULTS DSST performance improved with time awake (p < 0.0001) and across study days in both light exposure groups (p < 0.0001). There was no main effect of group, although we observed a significant day x group interaction (p = 0.0004), whereby participants exposed to BEL performed significantly better on the first two mornings after light exposures than participants in WL (post-hoc, p < 0.05). On those days, the BEL group showed higher EEG activity in some of the frequency bins in the sigma and beta range (p < 0.05) on the wake EEG. CONCLUSION Exposure to blue-enriched white light in the evening significantly improved DSST performance the following morning when compared to polychromatic white light. This was associated with a higher level of objective alertness on the wake EEG, but not with changes in sleep or circadian timing.
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Affiliation(s)
- Karine Scheuermaier
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States; Wits Sleep Laboratory, Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Mirjam Münch
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States; Sleep research and clinical chronobiology, Institute of Physiology, Charité Universitätsmedizin, Berlin, Germany; Clinic for Sleep and Chronomedicine, St. Hedwig-Krankenhaus, Berlin, Germany
| | - Joseph M Ronda
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States
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140
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Niemierzycka A, Tomczuk K, Mikicin M, Zdrodowska A, Orzechowski G, Kowalczyk M. Examinations of the methods used to power supply of different light sources and their effect on bioelectrical brain activity. Neurol Neurochir Pol 2018; 52:505-513. [PMID: 29559179 DOI: 10.1016/j.pjnns.2018.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE The article represents the preliminary study, with the aim of the experiment being to examine whether different types of light sources used commonly in building interiors combined with various color temperature have an effect on EEG activity. The effect of frequency pulsation and color temperature on brain activity in EEG examinations in the beta 2 band was assumed. MATERIAL/PARTICIPANTS Twenty healthy men aged 19-25 years participated in the experiment. METHODS The research stand was lit by: LED diodes with color temperatures of 3000K, 4200K, 6500K, with the power supplied using the pulse width modulation (PWM) method with the current frequency of 122Hz, linear fluorescent tubes (3000K, 6500K), with the power supplied with the frequency of 50Hz and 52kHz from the electromagnetic and electronic ballasts, and the conventional light bulb, with the power supplied directly from the mains electricity, used as a reference light. System Flex 30 apparatus with TrueScan software was used to record the EEG signal. The examination used two factors (speed and accuracy) of the Kraepelin's work curve to describe changes in work performance for various types of lighting. RESULTS The results demonstrate that the use of different types of emission of light and color temperature of the light have an effect on bioelectrical brain activity and work performance. CONCLUSIONS The highest activity of brain waves concerns the beta band in the frequency range of 21-22Hz, regardless of the type of the light source (LED, fluorescent tube). The methods used to supply power and color temperature of fluorescent tubes do not significantly affect bioelectrical brain activity during "work", but previous lighting with fluorescent tubes during work has an essential effect on bioelectrical brain activity during rest. Regardless of the color temperature, LED lighting with PWM power supply leads to the highest bioelectrical activity (mainly in the range of 21-22Hz) in the brain during work and rest, which might suggests the usefulness of this method of supplying power for everyday work. Incandescent light does not affect the bioelectrical brain activity during work and rest.
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Affiliation(s)
- Agnieszka Niemierzycka
- Józef Piłsudski University of Physical Education in Warsaw, Marymoncka 34, 00-968 Warsaw, Poland
| | | | - Mirosław Mikicin
- Józef Piłsudski University of Physical Education in Warsaw, Marymoncka 34, 00-968 Warsaw, Poland.
| | - Agnieszka Zdrodowska
- Józef Piłsudski University of Physical Education in Warsaw, Marymoncka 34, 00-968 Warsaw, Poland
| | - Grzegorz Orzechowski
- Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta, Finland
| | - Marek Kowalczyk
- Józef Piłsudski University of Physical Education in Warsaw, Marymoncka 34, 00-968 Warsaw, Poland
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141
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Pachito DV, Eckeli AL, Desouky AS, Corbett MA, Partonen T, Rajaratnam SMW, Riera R. Workplace lighting for improving alertness and mood in daytime workers. Cochrane Database Syst Rev 2018; 3:CD012243. [PMID: 29498416 PMCID: PMC6494162 DOI: 10.1002/14651858.cd012243.pub2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Exposure to light plays a crucial role in biological processes, influencing mood and alertness. Daytime workers may be exposed to insufficient or inappropriate light during daytime, leading to mood disturbances and decreases in levels of alertness. OBJECTIVES To assess the effectiveness and safety of lighting interventions to improve alertness and mood in daytime workers. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, seven other databases; ClinicalTrials.gov and the World Health Organization trials portal up to January 2018. SELECTION CRITERIA We included randomised controlled trials (RCTs), and non-randomised controlled before-after trials (CBAs) that employed a cross-over or parallel-group design, focusing on any type of lighting interventions applied for daytime workers. DATA COLLECTION AND ANALYSIS Two review authors independently screened references in two stages, extracted outcome data and assessed risk of bias. We used standardised mean differences (SMDs) and 95% confidence intervals (CI) to pool data from different questionnaires and scales assessing the same outcome across different studies. We combined clinically homogeneous studies in a meta-analysis. We used the GRADE system to rate quality of evidence. MAIN RESULTS The search yielded 2844 references. After screening titles and abstracts, we considered 34 full text articles for inclusion. We scrutinised reports against the eligibility criteria, resulting in the inclusion of five studies (three RCTs and two CBAs) with 282 participants altogether. These studies evaluated four types of comparisons: cool-white light, technically known as high correlated colour temperature (CCT) light versus standard illumination; different proportions of indirect and direct light; individually applied blue-enriched light versus no treatment; and individually applied morning bright light versus afternoon bright light for subsyndromal seasonal affective disorder.We found no studies comparing one level of illuminance versus another.We found two CBA studies (163 participants) comparing high CCT light with standard illumination. By pooling their results via meta-analysis we found that high CCT light may improve alertness (SMD -0.69, 95% CI -1.28 to -0.10; Columbia Jet Lag Scale and the Karolinska Sleepiness Scale) when compared to standard illumination. In one of the two CBA studies with 94 participants there was no difference in positive mood (mean difference (MD) 2.08, 95% CI -0.1 to 4.26) or negative mood (MD -0.45, 95% CI -1.84 to 0.94) assessed using the Positive and Negative Affect Schedule (PANAS) scale. High CCT light may have fewer adverse events than standard lighting (one CBA; 94 participants). Both studies were sponsored by the industry. We graded the quality of evidence as very low.We found no studies comparing light of a particular illuminance and light spectrum or CCT versus another combination of illuminance and light spectrum or CCT.We found no studies comparing daylight versus artificial light.We found one RCT (64 participants) comparing the effects of different proportions of direct and indirect light: 100% direct lighting, 70% direct lighting plus 30% indirect lighting, 30% direct lighting plus 70% indirect lighting and 100% indirect lighting. There was no substantial difference in mood, as assessed by the Beck Depression Inventory, or in adverse events, such as ocular, reading or concentration problems, in the short or medium term. We graded the quality of evidence as low.We found two RCTs comparing individually administered light versus no treatment. According to one RCT with 25 participants, blue-enriched light individually applied for 30 minutes a day may enhance alertness (MD -3.30, 95% CI -6.28 to -0.32; Epworth Sleepiness Scale) and may improve mood (MD -4.8, 95% CI -9.46 to -0.14; Beck Depression Inventory). We graded the quality of evidence as very low. One RCT with 30 participants compared individually applied morning bright light versus afternoon bright light for subsyndromal seasonal affective disorder. There was no substantial difference in alertness levels (MD 7.00, 95% CI -10.18 to 24.18), seasonal affective disorder symptoms (RR 1.60, 95% CI 0.81, 3.20; number of participants presenting with a decrease of at least 50% in SIGH-SAD scores) or frequency of adverse events (RR 0.53, 95% CI 0.26 to 1.07). Among all participants, 57% had a reduction of at least 50% in their SIGH-SAD score. We graded the quality of evidence as low.Publication bias could not be assessed for any of these comparisons. AUTHORS' CONCLUSIONS There is very low-quality evidence based on two CBA studies that high CCT light may improve alertness, but not mood, in daytime workers. There is very low-quality evidence based on one CBA study that high CCT light may also cause less irritability, eye discomfort and headache than standard illumination. There is low-quality evidence based on one RCT that different proportions of direct and indirect light in the workplace do not affect alertness or mood. There is very low-quality evidence based on one RCT that individually applied blue-enriched light improves both alertness and mood. There is low-quality evidence based on one RCT that individually administered bright light during the afternoon is as effective as morning exposure for improving alertness and mood in subsyndromal seasonal affective disorder.
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Affiliation(s)
- Daniela V Pachito
- Centro de Estudos de Saúde Baseada em Evidências e Avaliação Tecnológica em SaúdeCochrane BrazilRua Borges Lagoa, 564 cj 63São PauloSPBrazil04038‐000
| | - Alan L Eckeli
- São Paulo UniversityNeuroscience and Behavioural SciencesCampus UniversitarioRibeirão PretoSão PauloBrazil14.048‐900
| | | | - Mark A Corbett
- Corbett & Associates PtyLtdPO Box 477WalkervilleSouth AustraliaAustralia5081
| | - Timo Partonen
- National Institute for Health and WelfareDepartment of HealthMannerheimintie 166HelsinkiFinlandFI‐00300
| | - Shantha MW Rajaratnam
- Monash UniversitySchool of Psychological Sciences18 Innovation Walk (Building 17)Monash University Clayton CampusClaytonVictoriaAustralia3800
| | - Rachel Riera
- Centro de Estudos de Saúde Baseada em Evidências e Avaliação Tecnológica em SaúdeCochrane BrazilRua Borges Lagoa, 564 cj 63São PauloSPBrazil04038‐000
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142
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te Kulve M, Schlangen L, Schellen L, Souman JL, van Marken Lichtenbelt W. Correlated colour temperature of morning light influences alertness and body temperature. Physiol Behav 2018; 185:1-13. [DOI: 10.1016/j.physbeh.2017.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 01/08/2023]
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143
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Van der Maren S, Moderie C, Duclos C, Paquet J, Daneault V, Dumont M. Daily Profiles of Light Exposure and Evening Use of Light-emitting Devices in Young Adults Complaining of a Delayed Sleep Schedule. J Biol Rhythms 2018; 33:192-202. [PMID: 29463186 DOI: 10.1177/0748730418757007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A number of factors can contribute to a delayed sleep schedule. An important factor could be a daily profile of light exposure favoring a later circadian phase. This study aimed to compare light exposure between 14 young adults complaining of a delayed sleep schedule and 14 matched controls and to identify possible associations between habitual light exposure and circadian phase. Exposure to white and blue light was recorded with ambulatory monitors for 7 consecutive days. Participants also noted their daily use of light-emitting devices before bedtime. Endogenous circadian phase was estimated with the dim light melatonin onset (DLMO) in the laboratory. The amplitude of the light-dark cycle to which the subjects were exposed was smaller in delayed than in control subjects, and smaller amplitude was associated with a later DLMO. Smaller amplitude was due to both decreased exposure in the daytime and increased exposure at night. Total exposure to blue light, but not to white light, was lower in delayed subjects, possibly due to lower exposure to blue-rich outdoor light. Lower daily exposure to blue light was associated with a later DLMO. Timing of relative increases and decreases of light exposure in relation to endogenous circadian phase was also compared between the 2 groups. In delayed subjects, there was a relatively higher exposure to white and blue light 2 h after DLMO, a circadian time with maximal phase-delaying effect. Delayed participants also had higher exposure to light 8 to 10 h after DLMO, which occurred mostly during their sleep episode but may have some phase-advancing effects. Self-reported use of light-emitting devices before bedtime was higher in delayed than in control subjects and was associated with a later DLMO. This study suggests that individuals complaining of a delayed sleep schedule engage in light-related behaviors favoring a later circadian phase and a later bedtime.
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Affiliation(s)
- Solenne Van der Maren
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada.,Department of Psychology, University of Montreal, Montreal, QC, Canada
| | - Christophe Moderie
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada.,Department of Psychiatry, University of Montreal, Montreal, QC, Canada
| | - Catherine Duclos
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada.,Department of Psychiatry, University of Montreal, Montreal, QC, Canada
| | - Jean Paquet
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada
| | - Véronique Daneault
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada
| | - Marie Dumont
- Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, QC, Canada.,Department of Psychiatry, University of Montreal, Montreal, QC, Canada
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144
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Figueiro MG, Nagare R, Price L. Non-visual effects of light: how to use light to promote circadian entrainment and elicit alertness. LIGHTING RESEARCH & TECHNOLOGY (LONDON, ENGLAND : 2001) 2018; 50:38-62. [PMID: 30416392 PMCID: PMC6221201 DOI: 10.1177/1477153517721598] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In addition to stimulating the visual system, light incident on the retina stimulates other biological functions, also referred to as non-visual responses. Among the most notable biological functions are human circadian rhythms, which are bodily rhythms that, in constant darkness, oscillate with a period close to, but typically slightly longer than 24 hours. Twenty-four-hour light-dark patterns incident on the retina are the major synchronizer of circadian rhythms to the local time on Earth. Entrainment of circadian rhythms has been implicated in health and well-being. Light can also elicit an acute alerting effect on people, similar to a "cup of coffee." This review summarizes the literature on how light affects entrainment and alertness and how it can be used to achieve these aims.
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Affiliation(s)
- M G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - R Nagare
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Lla Price
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, UK
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145
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Souman JL, Tinga AM, te Pas SF, van Ee R, Vlaskamp BN. Acute alerting effects of light: A systematic literature review. Behav Brain Res 2018; 337:228-239. [DOI: 10.1016/j.bbr.2017.09.016] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 10/18/2022]
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146
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Bajaj S, Vanuk JR, Smith R, Dailey NS, Killgore WDS. Blue-Light Therapy following Mild Traumatic Brain Injury: Effects on White Matter Water Diffusion in the Brain. Front Neurol 2017; 8:616. [PMID: 29213254 PMCID: PMC5702646 DOI: 10.3389/fneur.2017.00616] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 11/06/2017] [Indexed: 11/13/2022] Open
Abstract
Mild traumatic brain injury (mTBI) is a common and often inconspicuous wound that is frequently associated with chronic low-grade symptoms and cognitive dysfunction. Previous evidence suggests that daily blue wavelength light therapy may be effective at reducing fatigue and improving sleep in patients recovering from mTBI. However, the effects of light therapy on recovering brain structure remain unexplored. In this study, we analyzed white matter diffusion properties, including generalized fractional anisotropy, and the quantity of water diffusion in isotropic (i.e., isotropic diffusion) and anisotropic fashion (i.e., quantitative anisotropy, QA) for fibers crossing 11 brain areas known to be significantly affected following mTBI. Specifically, we investigated how 6 weeks of daily morning blue light exposure therapy (compared to an amber-light placebo condition) impacted changes in white matter diffusion in individuals with mTBI. We observed a significant impact of the blue light treatment (relative to the placebo) on the amount of water diffusion (QA) for multiple brain areas, including the corpus callosum, anterior corona radiata, and thalamus. Moreover, many of these changes were associated with improvements in sleep latency and delayed memory. These findings suggest that blue wavelength light exposure may serve as one of the potential non-pharmacological treatments for facilitating structural and functional recovery following mTBI; they also support the use of QA as a reliable neuro-biomarker for mTBI therapies.
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Affiliation(s)
- Sahil Bajaj
- Social, Cognitive and Affective Neuroscience Laboratory (SCAN Lab), Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - John R Vanuk
- Social, Cognitive and Affective Neuroscience Laboratory (SCAN Lab), Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Ryan Smith
- Social, Cognitive and Affective Neuroscience Laboratory (SCAN Lab), Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Natalie S Dailey
- Social, Cognitive and Affective Neuroscience Laboratory (SCAN Lab), Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - William D S Killgore
- Social, Cognitive and Affective Neuroscience Laboratory (SCAN Lab), Department of Psychiatry, College of Medicine, University of Arizona, Tucson, AZ, United States
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147
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Lasauskaite R, Cajochen C. Influence of lighting color temperature on effort-related cardiac response. Biol Psychol 2017; 132:64-70. [PMID: 29133144 DOI: 10.1016/j.biopsycho.2017.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/23/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
Abstract
Higher color temperature refers to a higher proportion of blue spectral components of light, that are known to be associated with higher alertness state in humans. Based on motivational intensity theory (Brehm & Self, 1989), here we predicted that this lighting-induced alertness state should inform about the readiness to perform and this way influence subjective task demand and thus mental effort. To test this, study participants spent 15min under one of four lighting color temperature conditions and then performed a cognitive task. As predicted, effort-related cardiac response, indexed by a shortened cardiac pre-ejection period, decreased with increasing color temperature of light, as indicated by a significant single planned linear contrast. These results demonstrate that spectral properties of light can influence mental effort mobilization.
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Affiliation(s)
- Ruta Lasauskaite
- Centre for Chronobiology, Transfaculty Research Platform Molecular and Cognitive Neurosciences, Psychiatric Hospital of the University of Basel, University of Basel, Basel, Switzerland.
| | - Christian Cajochen
- Centre for Chronobiology, Transfaculty Research Platform Molecular and Cognitive Neurosciences, Psychiatric Hospital of the University of Basel, University of Basel, Basel, Switzerland
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148
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Sex differences in light sensitivity impact on brightness perception, vigilant attention and sleep in humans. Sci Rep 2017; 7:14215. [PMID: 29079823 PMCID: PMC5660221 DOI: 10.1038/s41598-017-13973-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 10/04/2017] [Indexed: 12/15/2022] Open
Abstract
Artificial light endows a "round-the-clock", 24-h/7-d society. Chronic exposure to light at night contributes to health hazards for humans, including disorders of sleep. Yet the influence of inter-individual traits, such as sex-differences, on light sensitivity remains to be established. Here we investigated potential sex-differences to evening light exposure of 40 lx at 6500 K (blue-enriched) or at 2500 K (non-blue-enriched), and their impact on brightness perception, vigilant attention and sleep physiology. In contrast to women, men had higher brightness perception and faster reaction times in a sustained attention task during blue-enriched light than non-blue-enriched. After blue-enriched light exposure, men had significantly higher all-night frontal NREM sleep slow-wave activity (SWA: 2-4 Hz), than women, particularly during the beginning of the sleep episode. Furthermore, brightness perception during blue-enriched light significantly predicted men's improved sustained attention performance and increased frontal NREM SWA. Our data indicate that, in contrast to women, men show a stronger response to blue-enriched light in the late evening even at very low light levels (40lux), as indexed by increased vigilant attention and sleep EEG hallmarks. Collectively, the data indicate that sex differences in light sensitivity might play a key role for ensuring the success of individually-targeted light interventions.
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149
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Chellappa SL, Lasauskaite R, Cajochen C. In a Heartbeat: Light and Cardiovascular Physiology. Front Neurol 2017; 8:541. [PMID: 29104560 PMCID: PMC5654948 DOI: 10.3389/fneur.2017.00541] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/27/2017] [Indexed: 12/22/2022] Open
Abstract
Light impinging on the retina fulfils a dual function: it serves for vision and it is required for proper entrainment of the endogenous circadian timing system to the 24-h day, thus influencing behaviors that promote health and optimal quality of life but are independent of image formation. The circadian pacemaker located in the suprachiasmatic nuclei modulates the cardiovascular system with an intrinsic ability to anticipate morning solar time and with a circadian nature of adverse cardiovascular events. Here, we infer that light exposure might affect cardiovascular function and provide evidence from existing research. Findings show a time-of-day dependent increase in relative sympathetic tone associated with bright light in the morning but not in the evening hours. Furthermore, dynamic light in the early morning hours can reduce the deleterious sleep-to-wake evoked transition on cardiac modulation. On the contrary, effects of numerous light parameters, such as illuminance level and wavelength of monochromatic light, on cardiac function are mixed. Therefore, in future research studies, light modalities, such as timing, duration, and its wavelength composition, should be taken in to account when testing the potential of light as a non-invasive countermeasure for adverse cardiovascular events.
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Affiliation(s)
- Sarah L Chellappa
- Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA, United States.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States
| | - Ruta Lasauskaite
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
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150
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Lee S, Muto N, Shimomura Y, Katsuura T. Human pupillary light reflex during successive irradiation with 1-ms blue- and green-pulsed light. J Physiol Anthropol 2017; 36:37. [PMID: 29041976 PMCID: PMC5646119 DOI: 10.1186/s40101-017-0153-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/10/2017] [Indexed: 11/16/2022] Open
Abstract
Background In the human retina, the contribution of intrinsically photosensitive retinal ganglion cells (ipRGCs) to the regulation of the pupillary response remains poorly understood. The objective of the current study was to determine the response dynamics of the pupillary light reflex to short, successive pulses of light. In order to better assess the roles of ipRGCs and cones, we used pulses of blue and green light. Methods Each participant was exposed to 1-ms blue (466 nm) and/or green (527 nm) light pulses simultaneously or separately, with inter-stimulus intervals (ISIs) of 0, 250, 500, 750, or 1000 ms. Pupil diameter was measured using an infrared camera system. Results We found that human pupillary light responses during simultaneous irradiation or successive irradiation with ISIs ≤ 250 ms were equivalent, though successive irradiation of blue- and green-pulsed light with ISIs ≥ 500 ms induced markedly increased pupillary constriction. Conclusions We propose that this result may be related to cell hyperpolarization that occurs in the retina just after the first light stimulus is turned off, with the threshold for this effect being between 250 and 500 ms in the human retina.
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Affiliation(s)
- Soomin Lee
- Center for Environment, Health and Field Sciences, Chiba University, 6-2-1, Kashiwanoha, Kashiwa, 277-0882, Japan.
| | - Naoko Muto
- Faculty of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yoshihiro Shimomura
- Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tetsuo Katsuura
- Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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