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Author Smith, G.; Vingrys, A.J.; Maddocks, J.D.; Hely, C.P. url  doi
openurl 
  Title Color recognition and discrimination under full-moon light Type Journal Article
  Year (up) 1994 Publication Applied Optics Abbreviated Journal Appl Opt  
  Volume 33 Issue 21 Pages 4741-4748  
  Keywords Human Health  
  Abstract The ability to recognize and discriminate colors under full-moon light was measured Color naming was performed at three sizes (0.5 degrees , 2 degrees , and 4 degrees ) by the use of one white and six colored chips that spanned the spectrum at two levels of saturation. The results show that correct color recognition is possible under full-moon light. However, the recognition rate depends on a complex interaction between hue, level of saturation, and size of test field. For small fields and desaturated colors, the recognition rate is low. However, for saturated colors, most hues can be recognized at better than chance levels, with red being recognized very accurately.  
  Address  
  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 0003-6935 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:20935847 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 531  
Permanent link to this record
 

 
Author Czeisler, C.A.; Shanahan, T.L.; Klerman, E.B.; Martens, H.; Brotman, D.J.; Emens, J.S.; Klein, T.; Rizzo, J.F. 3rd url  doi
openurl 
  Title Suppression of melatonin secretion in some blind patients by exposure to bright light Type Journal Article
  Year (up) 1995 Publication The New England Journal of Medicine Abbreviated Journal N Engl J Med  
  Volume 332 Issue 1 Pages 6-11  
  Keywords Human Health; Adolescent; Adult; Aged; Blindness/etiology/*physiopathology; Circadian Rhythm; Female; Humans; *Light; Male; Melatonin/blood/*secretion; Middle Aged; Photic Stimulation; Sleep Initiation and Maintenance Disorders/physiopathology; Visual Perception  
  Abstract BACKGROUND: Complete blindness generally results in the loss of synchronization of circadian rhythms to the 24-hour day and in recurrent insomnia. However, some blind patients maintain circadian entrainment. We undertook this study to determine whether some blind patients' eyes convey sufficient photic information to entrain the hypothalamic circadian pacemaker and suppress melatonin secretion, despite an apparently complete loss of visual function. METHODS: We evaluated the input of light to the circadian pacemaker by testing the ability of bright light to decrease plasma melatonin concentrations in 11 blind patients with no conscious perception of light and in 6 normal subjects. We also evaluated circadian entrainment over time in the blind patients. RESULTS: Plasma melatonin concentrations decreased during exposure to bright light in three sightless patients by an average (+/- SD) of 69 +/- 21 percent and in the normal subjects by an average of 66 +/- 15 percent. When two of these blind patients were tested with their eyes covered during exposure to light, plasma melatonin did not decrease. The three blind patients reported no difficulty sleeping and maintained apparent circadian entrainment to the 24-hour day. Plasma melatonin concentrations did not decrease during exposure to bright light in seven of the remaining blind patients; in the eighth, plasma melatonin was undetectable. These eight patients reported a history of insomnia, and in four the circadian temperature rhythm was not entrained to the 24-hour day. CONCLUSIONS: The visual subsystem that mediates light-induced suppression of melatonin secretion remains functionally intact in some sightless patients. The absence of photic input to the circadian system thus constitutes a distinct form of blindness, associated with periodic insomnia, that afflicts most but not all patients with no conscious perception of light.  
  Address Department of Medicine, Harvard Medical School, Boston, MA 02115  
  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 0028-4793 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:7990870 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 732  
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Author Boivin, D.B.; Duffy, J.F.; Kronauer, R.E.; Czeisler, C.A. url  doi
openurl 
  Title Dose-response relationships for resetting of human circadian clock by light Type Journal Article
  Year (up) 1996 Publication Nature Abbreviated Journal Nature  
  Volume 379 Issue 6565 Pages 540-542  
  Keywords Human Health; Adult; Body Temperature; Circadian Rhythm/*radiation effects; Dose-Response Relationship, Radiation; Humans; *Light; Male; NASA Discipline Number 18-10; NASA Discipline Regulatory Physiology; NASA Program Space Physiology and Countermeasures; Non-NASA Center  
  Abstract Since the first report in unicells, studies across diverse species have demonstrated that light is a powerful synchronizer which resets, in an intensity-dependent manner, endogenous circadian pacemakers. Although it is recognized that bright light (approximately 7,000 to 13,000 lux) is an effective circadian synchronizer in humans, it is widely believed that the human circadian pacemaker is insensitive to ordinary indoor illumination (approximately 50-300 lux). It has been proposed that the relationship between the resetting effect of light and its intensity follows a compressive nonlinear function, such that exposure to lower illuminances still exerts a robust effect. We therefore undertook a series of experiments which support this hypothesis and report here that light of even relatively low intensity (approximately 180 lux) significantly phase-shifts the human circadian pacemaker. Our results clearly demonstrate that humans are much more sensitive to light than initially suspected and support the conclusion that they are not qualitatively different from other mammals in their mechanism of circadian entrainment.  
  Address Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA  
  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 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8596632 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 722  
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Author Middleton, B.; Arendt, J.; Stone, BM url  openurl
  Title Human circadian rhythms in constant dim light (8 lux) with knowledge of clock time Type Journal Article
  Year (up) 1996 Publication Journal of Sleep Research Abbreviated Journal J. Sleep Res.  
  Volume 5 Issue 2 Pages 69-76  
  Keywords Human Health; circadian rhythm; light/dark cycle; melatonin; entrainment; melatonin levels; 6-sulphatoxymelatonin  
  Abstract The light/dark (L/D) cycle is a major synchronizer of human circadian rhythms. In the absence of a strong L/D cycle, synchrony with 24 hours can nevertheless be maintained in a socially structured environment, as shown in Polar regions (Broadway et al. 1987) and by some blind subjects (Czeisler et al. 1995a). The relative contribution of other time cues to entrainment in dim light has not been fully explored. The present study investigated the behaviour of melatonin (assessed as 6-sulphatoxymelatonin); rectal temperature; activity and sleep (actigraphy and logs) in constant dim light (L/ L) with access to a digital clock. 6 normal healthy males were maintained as a group in partial temporal isolation with attenuated sound and ambient temperature for 21 days. All 6 subjects showed free-running periodicity for 6-sulphatoxymelatonin and 5/6 subjects for temperature, activity and sleep offset. The average period (tau) was 24.26 +/- 0.049, substantially shorter than in previous experiments with a self selected L/D cycle but similar to a recent study conducted in very dim light. One subject maintained a rigid sleep/wake cycle throughout whilst his 6-sulphatoxymelatonin rhythm free-ran. Total sleep time, from actigraph data, did not change but sleep efficiency decreased during the experiment. The subjects did not show group synchronization. These results confirm previous data indicating the importance of the L/D cycle in human entrainment and underline the lesser role of social cues and knowledge of clock time. This particular approach will permit the administration of timed medication to sighted humans under free-running conditions.  
  Address  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language Summary Language Original Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1098  
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Author Brainard, G.C.; Rollag, M.D.; Hanifin, J.P. url  doi
openurl 
  Title Photic Regulation of Melatonin in Humans: Ocular and Neural Signal Transduction Type Journal Article
  Year (up) 1997 Publication Journal of Biological Rhythms Abbreviated Journal Journal of Biological Rhythms  
  Volume 12 Issue 6 Pages 537-546  
  Keywords Human Health; eye; lens; light; melatonin suppression; photoreceptor; pineal gland; pupil  
  Abstract  
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  Series Volume Series Issue Edition  
  ISSN 0748-7304 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ schroer @ Serial 583  
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