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Author Nordt, A.; Klenke, R. url  doi
openurl 
  Title Sleepless in town--drivers of the temporal shift in dawn song in urban European blackbirds Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 8 Pages e71476  
  Keywords Animals; Automobiles; Cities; Ecosystem; Germany; Humans; Light; Male; Noise; Photoperiod; Sleep; Songbirds/*physiology; Urban Population; *Vocalization, Animal; dawn chorus; morning chorus  
  Abstract Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. time their dawn song according to changing light intensities. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds (Turdus merula). We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds.  
  Address Helmholtz Centre for Environmental Research – UFZ, Department of Conservation Biology, Leipzig, Germany. anja.nordt@ufz.de  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23940759; PMCID:PMC3737108 Approved no  
  Call Number IDA @ john @ Serial 43  
Permanent link to this record
 

 
Author Fonken, L.K.; Aubrecht, T.G.; Melendez-Fernandez, O.H.; Weil, Z.M.; Nelson, R.J. url  doi
openurl 
  Title Dim light at night disrupts molecular circadian rhythms and increases body weight Type Journal Article
  Year 2013 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms  
  Volume 28 Issue 4 Pages 262-271  
  Keywords Animals; Blood Glucose/metabolism; Body Weight/*physiology; CLOCK Proteins/biosynthesis/genetics; Circadian Rhythm/*physiology; Corticosterone/metabolism; Feeding Behavior/physiology; Immunohistochemistry; Light; *Lighting; Male; Mice; Motor Activity; Polymerase Chain Reaction; Suprachiasmatic Nucleus/metabolism/physiology; clock genes; feeding rhythm; light pollution; obesity  
  Abstract With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.  
  Address Department of Neuroscience and Institute for Behavioral Medicine Research, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA. fonken.1@osu.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0748-7304 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23929553; PMCID:PMC4033305 Approved no  
  Call Number IDA @ john @ Serial 28  
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Author Bedrosian, T.A.; Vaughn, C.A.; Galan, A.; Daye, G.; Weil, Z.M.; Nelson, R.J. url  doi
openurl 
  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  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0270-6474 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23926261 Approved no  
  Call Number IDA @ john @ Serial 27  
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Author Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D. url  doi
openurl 
  Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
  Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 23 Issue 16 Pages 1554-1558  
  Keywords Human Health; Adult; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight; Young Adult; Circadian Rhythm  
  Abstract The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks.  
  Address Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309-0354, USA. kenneth.wright@colorado.edu  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23910656; PMCID:PMC4020279 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 505  
Permanent link to this record
 

 
Author Chang, A.-M.; Scheer, F.A.J.L.; Czeisler, C.A.; Aeschbach, D. url  doi
openurl 
  Title Direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans depend on prior light history Type Journal Article
  Year 2013 Publication Sleep Abbreviated Journal Sleep  
  Volume 36 Issue 8 Pages 1239-1246  
  Keywords Arousal/*radiation effects; Attention/radiation effects; Cross-Over Studies; *Electroencephalography; Female; Humans; *Light; Male; Melatonin/blood/physiology; Psychomotor Performance/radiation effects; Reaction Time; Wakefulness/*radiation effects; Young Adult; Light history; alertness and performance; light exposure  
  Abstract STUDY OBJECTIVES: Light can induce an acute alerting response in humans; however, it is unknown whether the magnitude of this response is simply a function of the absolute illuminance of the light itself, or whether it depends on illuminance history preceding the stimulus. Here, we compared the effects of illuminance history on the alerting response to a subsequent light stimulus. DESIGN: A randomized, crossover design was used to compare the effect of two illuminance histories (1 lux vs. 90 lux) on the alerting response to a 6.5-h 90-lux light stimulus during the biological night. SETTING: Intensive Physiologic Monitoring Unit, Brigham and Women's Hospital, Boston, MA. PARTICIPANTS: Fourteen healthy young adults (6 F; 23.5 +/- 2.9 years). INTERVENTIONS: Participants were administered two 6.5-h light exposures (LE) of 90 lux during the biological night. For 3 days prior to each LE, participants were exposed to either 1 lux or 90 lux during the wake episode. MEASUREMENTS AND RESULTS: The alerting response to light was assessed using subjective sleepiness ratings, lapses of attention, and reaction times as measured with an auditory psychomotor vigilance task, as well as power density in the delta/theta range of the waking EEG. The alerting response to light was greater and lasted longer when the LE followed exposure to 1 lux compared to 90 lux light. CONCLUSION: The magnitude and duration of the alerting effect of light at night depends on the illuminance history and appears to be subject to sensitization and adaptation.  
  Address Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. amchang@rics.bwh.harvard.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0161-8105 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23904684; PMCID:PMC3700721 Approved no  
  Call Number IDA @ john @ Serial 145  
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