|   | 
Details
   web
Records
Author (up) Bedrosian, T.A. (ed)
Title Circadian Disruption by Light at Night: Implications for Mood Type Book Whole
Year 2013 Publication Abbreviated Journal
Volume Issue Pages
Keywords circadian disruption; sleep; light at night; melanopsin; mood; mental health; Mood Disorders; epigenetics; red light
Abstract Life on Earth has adapted to a consistent 24-h solar cycle. Circadian rhythms in physiology and behavior remain synchronized to the environment using light as the most potent entraining cue. During the past century, however, the widespread adoption of electric light has led to `round-the-clock’ societies. Instead of aligning with the environment, individuals follow artificial and often erratic light cycles created by social and work schedules. In particular, exposure to artificial light at night (LAN), termed “light pollution”, has become pervasive over the past 100 years. Virtually every individual living in the U.S. and Europe experiences this aberrant light exposure, and moreover about 20% of the population performs shift work. LAN may disrupt physiological timekeeping, leading to dysregulation of internal processes and misalignment between behavior and the environment. Recent evidence suggests that individuals exposed to excessive LAN, such as night shift workers, have increased risk for depressive disorders, but the biological mechanism remains unspecified. In mammals, intrinsically photosensitive retinal ganglion cells (ipRGCs) project light information to (1) the suprachiasmatic nucleus (SCN) in the hypothalamus, regulating circadian rhythms, and (2) to limbic regions, putatively regulating mood. Thus, LAN has the potential to affect both circadian timekeeping and mood. In this dissertation, I present evidence from rodent studies supporting the novel hypothesis that night-time exposure to light disrupts circadian organization and contributes to depressed mood. First, I consider the physiological and behavioral consequences associated with unnatural exposure to LAN. The effects of LAN on circadian output are considered in terms of locomotor activity, the diurnal cortisol rhythm, and diurnal clock protein expression in the brain in Chapter 2. The influence of LAN on behavior and brain plasticity is discussed, with particular focus on depressive-like behavior (Chapter 3) and effects of SSRI treatment (Chapter 4). Effects of LAN on structural plasticity and gene expression in the brain are described, with emphasis on potential correlates of the depressive-like behavior observed under LAN in Chapter 5. Given the prevalence of LAN exposure and its importance, strategies for reversing the effects are offered. Specifically, eliminating LAN quickly reverses behavioral and physiological effects of exposure as described in Chapter 5. In Chapter 6 I report that administration of a pharmacological cytokine inhibitor prevents depressive-like behaviors in LAN, implicating brain inflammation in the behavioral effect. Finally, I demonstrate in Chapter 7 that exposure to red wavelength LAN reduces the effects on brain and behavior, suggesting that LAN acts through specific retinal pathways involving melanopsin. Taken together, these studies demonstrate the consequences of LAN, but also outline potential avenues for prevention or intervention.
Address Department of Neuroscience and The Institute for Behavioral Medicine Research The Ohio State University
Corporate Author Thesis Ph.D. thesis
Publisher Place of Publication Editor Bedrosian, T.A.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 323
Permanent link to this record
 

 
Author (up) Bedrosian, T.A.; Vaughn, C.A.; Galan, A.; Daye, G.; Weil, Z.M.; Nelson, R.J.
Title Nocturnal light exposure impairs affective responses in a wavelength-dependent manner Type Journal Article
Year 2013 Publication The Journal of Neuroscience : the Official Journal of the Society for Neuroscience Abbreviated Journal J Neurosci
Volume 33 Issue 32 Pages 13081-13087
Keywords Analysis of Variance; Animals; Circadian Rhythm/*physiology; Cricetinae; Dose-Response Relationship, Radiation; Female; Food Deprivation/physiology; Food Preferences/physiology/radiation effects; Fourier Analysis; Gene Expression Regulation/radiation effects; Hippocampus/pathology/radiation effects; Immobility Response, Tonic/radiation effects; Light/*adverse effects; Mood Disorders/*etiology/pathology; Motor Activity/physiology/radiation effects; Phodopus; Proto-Oncogene Proteins c-fos/metabolism; Social Behavior; Suprachiasmatic Nucleus/metabolism; Time Factors
Abstract Life on earth is entrained to a 24 h solar cycle that synchronizes circadian rhythms in physiology and behavior; light is the most potent entraining cue. In mammals, light is detected by (1) rods and cones, which mediate visual function, and (2) intrinsically photosensitive retinal ganglion cells (ipRGCs), which primarily project to the suprachiasmatic nucleus (SCN) in the hypothalamus to regulate circadian rhythms. Recent evidence, however, demonstrates that ipRGCs also project to limbic brain regions, suggesting that, through this pathway, light may have a role in cognition and mood. Therefore, it follows that unnatural exposure to light may have negative consequences for mood or behavior. Modern environmental lighting conditions have led to excessive exposure to light at night (LAN), and particularly to blue wavelength lights. We hypothesized that nocturnal light exposure (i.e., dim LAN) would induce depressive responses and alter neuronal structure in hamsters (Phodopus sungorus). If this effect is mediated by ipRGCs, which have reduced sensitivity to red wavelength light, then we predicted that red LAN would have limited effects on brain and behavior compared with shorter wavelengths. Additionally, red LAN would not induce c-Fos activation in the SCN. Our results demonstrate that exposure to LAN influences behavior and neuronal plasticity and that this effect is likely mediated by ipRGCs. Modern sources of LAN that contain blue wavelengths may be particularly disruptive to the circadian system, potentially contributing to altered mood regulation.
Address Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA. Bedrosian.2@osu.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0270-6474 ISBN Medium
Area Expedition Conference
Notes PMID:23926261 Approved no
Call Number IDA @ john @ Serial 27
Permanent link to this record
 

 
Author (up) Bedrosian, T.A.; Weil, Z.M.; Nelson, R.J.
Title Chronic dim light at night provokes reversible depression-like phenotype: possible role for TNF Type Journal Article
Year 2013 Publication Molecular Psychiatry Abbreviated Journal
Volume 18 Issue Pages 930-936
Keywords Animals
Abstract The prevalence of major depression has increased in recent decades and women are twice as likely as men to develop the disorder. Recent environmental changes almost certainly have a role in this phenomenon, but a complete set of contributors remains unspecified. Exposure to artificial light at night (LAN) has surged in prevalence during the past 50 years, coinciding with rising rates of depression. Chronic exposure to LAN is linked to increased risk of breast cancer, obesity and mood disorders, although the relationship to mood is not well characterized. In this study, we investigated the effects of chronic exposure to 5 lux LAN on depression-like behaviors in female hamsters. Using this model, we also characterized hippocampal brain-derived neurotrophic factor expression and hippocampal dendritic morphology, and investigated the reversibility of these changes 1, 2 or 4 weeks following elimination of LAN. Furthermore, we explored the mechanism of action, focusing on hippocampal proinflammatory cytokines given their dual role in synaptic plasticity and the pathogenesis of depression. Using reverse transcription-quantitative PCR, we identified a reversible increase in hippocampal tumor necrosis factor (TNF), but not interleukin-1β, mRNA expression in hamsters exposed to LAN. Direct intracerebroventricular infusion of a dominant-negative inhibitor of soluble TNF, XPro1595, prevented the development of depression-like behavior under LAN, but had no effect on dendritic spine density in the hippocampus. These results indicate a partial role for TNF in the reversible depression-like phenotype observed under chronic dim LAN. Recent environmental changes, such as LAN exposure, may warrant more attention as possible contributors to rising rates of mood disorders.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 386
Permanent link to this record
 

 
Author (up) Bolshakov, C.V.; Bulyuk, V.N.; Sinelschikova, A.Y.; Vorotkov, M.V.
Title Influence of the vertical light beam on numbers and flight trajectories of night-migrating songbirds Type Journal Article
Year 2013 Publication Avian Ecol. Behav. Abbreviated Journal
Volume 24 Issue Pages 35–49
Keywords Animals; nocturnal migration; light pollution; numbers; flight track; extrinsic factors
Abstract In this paper we analyse the data obtained in the automatic regime by the Optical Electronic Device (OED, Vorotkov et al. 2009; Bolshakov et al. 2010) for autumn nocturnal passage of passerines on the Courish Spit on the Baltic Sea and estimate: (1) numbers aloft under differ- ent types of wind (following wind, opposing wind and calm conditions); (2) flight trajectories in the 5° cone of white light. We found that under natural nocturnal illumination conditions, the vertical cone of white light impacts the detectable numbers aloft and disturbs straight flight trajectories. The OED data obtained throughout the night suggest, after correction for ground speed and the mean flight altitude, the actual number of birds in the light cone peaks at calm conditions, is halved under following winds which are optimal for passage and is 21 times lower under unfavourable headwinds. It is assumed that high numbers in the light cone under calm conditions is an artefact of bird attraction by light and their concentration around the searchlights. The OED data obtained for midnight ±1 hour, flying migrants respond to the vertical light cone under all types of wind conditions by altering their straight flight trajec- tories. However, this response is most apparent in still air conditions. The proportion of birds that change their flight track reaches 43%. We assume that under such conditions some birds are not only attracted to the illuminated zone at low altitudes, but, besides slowing down their ground speed, change their trajectories to the degree of flying in circles. To determine combi- nations of factors and to test for their possible impact on the probability of response to light, we used a binary logistic regression. The presence of birds with straight vs. curved tracks was used as the dependent variable. Final logistic models obtained for midnight ±1 hour for calm conditions and headwinds, suggest that occurrence probability of songbirds with curvilinear flight tracks is higher for small birds, when no or just a small part of Moon disk is visible and under high air humidity. Under headwinds the probability of occurrence of birds flying curvi- linear tracks is also higher under overcast. For following winds, the probability of occurrence birds flying curvilinearly was higher when many small birds were aloft, when air humidity was high and when wind was not strictly following. Unlike other wind situations, this model did not include the size of visible part of the Moon disk as a significant factor. The increase of occurrence of curvilinear flight tracks through the light beam when winds were not exactly following was probably caused by the problems with compensating the lateral component of tailwinds under high velocities, especially by small birds.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 378
Permanent link to this record
 

 
Author (up) Brainard, G.C.; Coyle, W.; Ayers, M.; Kemp, J.; Warfield, B.; Maida, J.; Bowen, C.; Bernecker, C.; Lockley, S.W.; Hanifin, J.P.
Title Solid-state lighting for the International Space Station: Tests of visual performance and melatonin regulation Type Journal Article
Year 2013 Publication Acta Astronautica Abbreviated Journal Acta Astronautica
Volume 92 Issue 1 Pages 21-28
Keywords Human Health; Lighting
Abstract The International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts' working and living environments. Solid-state light emitting diodes (LEDs) are attractive candidates for replacing the GLAs on the ISS. The advantages of LEDs over conventional fluorescent light sources include lower up-mass, power consumption and heat generation, as well as fewer toxic materials, greater resistance to damage and long lamp life. A prototype Solid-State Lighting Assembly (SSLA) was developed and successfully installed on the ISS. The broad aim of the ongoing work is to test light emitted by prototype SSLAs for supporting astronaut vision and assessing neuroendocrine, circadian, neurobehavioral and sleep effects. Three completed ground-based studies are presented here including experiments on visual performance, color discrimination, and acute plasma melatonin suppression in cohorts of healthy, human subjects under different SSLA light exposure conditions within a high-fidelity replica of the ISS Crew Quarters (CQ). All visual tests were done under indirect daylight at 201 lx, fluorescent room light at 531 lx and 4870 K SSLA light in the CQ at 1266 lx. Visual performance was assessed with numerical verification tests (NVT). NVT data show that there are no significant differences in score (F=0.73, p=0.48) or time (F=0.14, p=0.87) for subjects performing five contrast tests (10%–100%). Color discrimination was assessed with Farnsworth-Munsell 100 Hue tests (FM-100). The FM-100 data showed no significant differences (F=0.01, p=0.99) in color discrimination for indirect daylight, fluorescent room light and 4870 K SSLA light in the CQ. Plasma melatonin suppression data show that there are significant differences (F=29.61, p<0.0001) across the percent change scores of plasma melatonin for five corneal irradiances, ranging from 0 to 405 &#956;W/cm2 of 4870 K SSLA light in the CQ (0–1270 lx). Risk factors for the health and safety of astronauts include disturbed circadian rhythms and altered sleep–wake patterns. These studies will help determine if SSLA lighting can be used both to support astronaut vision and serve as an in-flight countermeasure for circadian desynchrony, sleep disruption and cognitive performance deficits on the ISS.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0094-5765 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1533
Permanent link to this record