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Author Narendra, A.; Reid, S.F.; Raderschall, C.A. url  doi
openurl 
  Title Navigational efficiency of nocturnal Myrmecia ants suffers at low light levels Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 3 Pages e58801  
  Keywords Adaptation, Biological/*physiology; Animals; Ants/*physiology; Australian Capital Territory; *Cues; Geographic Information Systems; Homing Behavior/*physiology; *Light; Locomotion/*physiology; Orientation/*physiology; insects  
  Abstract Insects face the challenge of navigating to specific goals in both bright sun-lit and dim-lit environments. Both diurnal and nocturnal insects use quite similar navigation strategies. This is despite the signal-to-noise ratio of the navigational cues being poor at low light conditions. To better understand the evolution of nocturnal life, we investigated the navigational efficiency of a nocturnal ant, Myrmecia pyriformis, at different light levels. Workers of M. pyriformis leave the nest individually in a narrow light-window in the evening twilight to forage on nest-specific Eucalyptus trees. The majority of foragers return to the nest in the morning twilight, while few attempt to return to the nest throughout the night. We found that as light levels dropped, ants paused for longer, walked more slowly, the success in finding the nest reduced and their paths became less straight. We found that in both bright and dark conditions ants relied predominantly on visual landmark information for navigation and that landmark guidance became less reliable at low light conditions. It is perhaps due to the poor navigational efficiency at low light levels that the majority of foragers restrict navigational tasks to the twilight periods, where sufficient navigational information is still available.  
  Address (up) ARC Centre of Excellence in Vision Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia. ajay.narendra@anu.edu.au  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23484052; PMCID:PMC3590162 Approved no  
  Call Number IDA @ john @ Serial 117  
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Author Bijveld, M.M.C.; van Genderen, M.M.; Hoeben, F.P.; Katzin, A.A.; van Nispen, R.M.A.; Riemslag, F.C.C.; Kappers, A.M.L. url  doi
openurl 
  Title Assessment of night vision problems in patients with congenital stationary night blindness Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 5 Pages e62927  
  Keywords Vision; Adolescent; Adult; Case-Control Studies; Child; *Dark Adaptation; Electroretinography; Eye Diseases, Hereditary/*physiopathology; Female; Genetic Diseases, X-Linked/*physiopathology; Humans; Light; Male; Middle Aged; Myopia/*physiopathology; Night Blindness/*physiopathology; *Night Vision; *Pattern Recognition, Visual; Surveys and Questionnaires; *Visual Acuity; Visual Fields  
  Abstract Congenital Stationary Night Blindness (CSNB) is a retinal disorder caused by a signal transmission defect between photoreceptors and bipolar cells. CSNB can be subdivided in CSNB2 (rod signal transmission reduced) and CSNB1 (rod signal transmission absent). The present study is the first in which night vision problems are assessed in CSNB patients in a systematic way, with the purpose of improving rehabilitation for these patients. We assessed the night vision problems of 13 CSNB2 patients and 9 CSNB1 patients by means of a questionnaire on low luminance situations. We furthermore investigated their dark adapted visual functions by the Goldmann Weekers dark adaptation curve, a dark adapted static visual field, and a two-dimensional version of the “Light Lab”. In the latter test, a digital image of a living room with objects was projected on a screen. While increasing the luminance of the image, we asked the patients to report on detection and recognition of objects. The questionnaire showed that the CSNB2 patients hardly experienced any night vision problems, while all CSNB1 patients experienced some problems although they generally did not describe them as severe. The three scotopic tests showed minimally to moderately decreased dark adapted visual functions in the CSNB2 patients, with differences between patients. In contrast, the dark adapted visual functions of the CSNB1 patients were more severely affected, but showed almost no differences between patients. The results from the “2D Light Lab” showed that all CSNB1 patients were blind at low intensities (equal to starlight), but quickly regained vision at higher intensities (full moonlight). Just above their dark adapted thresholds both CSNB1 and CSNB2 patients had normal visual fields. From the results we conclude that night vision problems in CSNB, in contrast to what the name suggests, are not conspicuous and generally not disabling.  
  Address (up) Bartimeus Institute for the Visually Impaired, Zeist, The Netherlands. mbijveld@bartimeus.nl  
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  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23658786; PMCID:PMC3643903 Approved no  
  Call Number GFZ @ kyba @ Serial 3051  
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Author Summa, K.C.; Vitaterna, M.H.; Turek, F.W. url  doi
openurl 
  Title Environmental perturbation of the circadian clock disrupts pregnancy in the mouse Type Journal Article
  Year 2012 Publication PloS one Abbreviated Journal PLoS One  
  Volume 7 Issue 5 Pages e37668  
  Keywords Animals; Circadian Rhythm/*physiology; *Environment; Female; Locomotion/physiology; Mice; Mice, Inbred C57BL; Photoperiod; Pregnancy; Pregnancy Outcome; Reproduction/*physiology  
  Abstract BACKGROUND: The circadian clock has been linked to reproduction at many levels in mammals. Epidemiological studies of female shift workers have reported increased rates of reproductive abnormalities and adverse pregnancy outcomes, although whether the cause is circadian disruption or another factor associated with shift work is unknown. Here we test whether environmental disruption of circadian rhythms, using repeated shifts of the light:dark (LD) cycle, adversely affects reproductive success in mice. METHODOLOGY/PRINCIPAL FINDINGS: Young adult female C57BL/6J (B6) mice were paired with B6 males until copulation was verified by visual identification of vaginal plug formation. Females were then randomly assigned to one of three groups: control, phase-delay or phase-advance. Controls remained on a constant 12-hr light:12-hr dark cycle, whereas phase-delayed and phase-advanced mice were subjected to 6-hr delays or advances in the LD cycle every 5-6 days, respectively. The number of copulations resulting in term pregnancies was determined. Control females had a full-term pregnancy success rate of 90% (11/12), which fell to 50% (9/18; p<0.1) in the phase-delay group and 22% (4/18; p<0.01) in the phase-advance group. CONCLUSIONS/SIGNIFICANCE: Repeated shifting of the LD cycle, which disrupts endogenous circadian timekeeping, dramatically reduces pregnancy success in mice. Advances of the LD cycle have a greater negative impact on pregnancy outcomes and, in non-pregnant female mice, require longer for circadian re-entrainment, suggesting that the magnitude or duration of circadian misalignment may be related to the severity of the adverse impact on pregnancy. These results explicitly link disruptions of circadian entrainment to adverse pregnancy outcomes in mammals, which may have important implications for the reproductive health of female shift workers, women with circadian rhythm sleep disorders and/or women with disturbed circadian rhythms for other reasons.  
  Address (up) Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America  
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  Language English Summary Language Original Title  
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  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22649550; PMCID:PMC3359308 Approved no  
  Call Number IDA @ john @ Serial 92  
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Author Chellappa, S.L.; Steiner, R.; Blattner, P.; Oelhafen, P.; Gotz, T.; Cajochen, C. url  doi
openurl 
  Title Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert? Type Journal Article
  Year 2011 Publication PloS one Abbreviated Journal PLoS One  
  Volume 6 Issue 1 Pages e16429  
  Keywords Circadian Rhythm/radiation effects; Cognition/*radiation effects; Color; Cross-Over Studies; Fluorescence; Humans; *Light; Male; Melatonin/*radiation effects; Reaction Time/*radiation effects; Young Adult; blue light  
  Abstract BACKGROUND: Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance. METHODS: Sixteen healthy young men were studied in a balanced cross-over design with light exposure of 3 different light settings (compact fluorescent lamps with light of 40 lux at 6500K and at 2500K and incandescent lamps of 40 lux at 3000K) during 2 h in the evening. RESULTS: Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task), but not in tasks associated with executive function (Paced Visual Serial Addition Task). This cognitive improvement was strongly related with attenuated salivary melatonin levels, particularly for the light condition at 6500K. CONCLUSIONS: Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.  
  Address (up) Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland  
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  ISSN 1932-6203 ISBN Medium  
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  Notes PMID:21298068; PMCID:PMC3027693 Approved no  
  Call Number IDA @ john @ Serial 286  
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Author Bonmati-Carrion, M.A.; Hild, K.; Isherwood, C.; Sweeney, S.J.; Revell, V.L.; Skene, D.J.; Rol, M.A.; Madrid, J.A. url  doi
openurl 
  Title Relationship between Human Pupillary Light Reflex and Circadian System Status Type Journal Article
  Year 2016 Publication PloS one Abbreviated Journal PLoS One  
  Volume 11 Issue 9 Pages e0162476  
  Keywords Human Health  
  Abstract Intrinsically photosensitive retinal ganglion cells (ipRGCs), whose photopigment melanopsin has a peak of sensitivity in the short wavelength range of the spectrum, constitute a common light input pathway to the olivary pretectal nucleus (OPN), the pupillary light reflex (PLR) regulatory centre, and to the suprachiasmatic nuclei (SCN), the major pacemaker of the circadian system. Thus, evaluating PLR under short wavelength light (lambdamax </= 500 nm) and creating an integrated PLR parameter, as a possible tool to indirectly assess the status of the circadian system, becomes of interest. Nine monochromatic, photon-matched light stimuli (300 s), in 10 nm increments from lambdamax 420 to 500 nm were administered to 15 healthy young participants (8 females), analyzing: i) the PLR; ii) wrist temperature (WT) and motor activity rhythms (WA), iii) light exposure (L) pattern and iv) diurnal preference (Horne-Ostberg), sleep quality (Pittsburgh) and daytime sleepiness (Epworth). Linear correlations between the different PLR parameters and circadian status index obtained from WT, WA and L recordings and scores from questionnaires were calculated. In summary, we found markers of robust circadian rhythms, namely high stability, reduced fragmentation, high amplitude, phase advance and low internal desynchronization, were correlated with a reduced PLR to 460-490 nm wavelengths. Integrated circadian (CSI) and PLR (cp-PLR) parameters are proposed, that also showed an inverse correlation. These results demonstrate, for the first time, the existence of a close relationship between the circadian system robustness and the pupillary reflex response, two non-visual functions primarily under melanopsin-ipRGC input.  
  Address (up) Chronobiology Laboratory, Department of Physiology, Faculty of Biology, University of Murcia, IMIB-Arrixaca, 30100, Espinardo, Murcia, Spain  
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  Language English Summary Language Original Title  
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  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:27636197; PMCID:PMC5026360 Approved no  
  Call Number LoNNe @ kyba @ Serial 1537  
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