|   | 
Details
   web
Records
Author Lockley, S.W.; Brainard, G.C.; Czeisler, C.A.
Title High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light Type Journal Article
Year 2003 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume 88 Issue 9 Pages 4502-4505
Keywords Human Health; Adult; Area Under Curve; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Male; Melatonin/*metabolism; Pineal Gland/metabolism/radiation effects; Saliva/metabolism; Non-programmatic
Abstract The endogenous circadian oscillator in mammals, situated in the suprachiasmatic nuclei, receives environmental photic input from specialized subsets of photoreceptive retinal ganglion cells. The human circadian pacemaker is exquisitely sensitive to ocular light exposure, even in some people who are otherwise totally blind. The magnitude of the resetting response to white light depends on the timing, intensity, duration, number and pattern of exposures. We report here that the circadian resetting response in humans, as measured by the pineal melatonin rhythm, is also wavelength dependent. Exposure to 6.5 h of monochromatic light at 460 nm induces a two-fold greater circadian phase delay than 6.5 h of 555 nm monochromatic light of equal photon density. Similarly, 460 nm monochromatic light causes twice the amount of melatonin suppression compared to 555 nm monochromatic light, and is dependent on the duration of exposure in addition to wavelength. These studies demonstrate that the peak of sensitivity of the human circadian pacemaker to light is blue-shifted relative to the three-cone visual photopic system, the sensitivity of which peaks at approximately 555 nm. Thus photopic lux, the standard unit of illuminance, is inappropriate when quantifying the photic drive required to reset the human circadian pacemaker.
Address (up) Division of Sleep Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA
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 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:12970330 Approved no
Call Number LoNNe @ kagoburian @ Serial 778
Permanent link to this record
 

 
Author Chang, A.-M.; Scheer, F.A.J.L.; Czeisler, C.A.; Aeschbach, D.
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 (up) Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. amchang@rics.bwh.harvard.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 0161-8105 ISBN Medium
Area Expedition Conference
Notes PMID:23904684; PMCID:PMC3700721 Approved no
Call Number IDA @ john @ Serial 145
Permanent link to this record
 

 
Author Wright, K.P.J.; Hull, J.T.; Czeisler, C.A.
Title Relationship between alertness, performance, and body temperature in humans Type Journal Article
Year 2002 Publication American Journal of Physiology. Regulatory, Integrative and Comparative Physiology Abbreviated Journal Am J Physiol Regul Integr Comp Physiol
Volume 283 Issue 6 Pages R1370-7
Keywords Human Health; Adult; Attention/*physiology; *Body Temperature; Circadian Rhythm/physiology; Cognition/*physiology; Female; Humans; Male; Memory/physiology; Reaction Time; Sleep/physiology; Time Factors; Wakefulness/physiology; NASA Discipline Regulatory Physiology; Non-NASA Center
Abstract Body temperature has been reported to influence human performance. Performance is reported to be better when body temperature is high/near its circadian peak and worse when body temperature is low/near its circadian minimum. We assessed whether this relationship between performance and body temperature reflects the regulation of both the internal biological timekeeping system and/or the influence of body temperature on performance independent of circadian phase. Fourteen subjects participated in a forced desynchrony protocol allowing assessment of the relationship between body temperature and performance while controlling for circadian phase and hours awake. Most neurobehavioral measures varied as a function of internal biological time and duration of wakefulness. A number of performance measures were better when body temperature was elevated, including working memory, subjective alertness, visual attention, and the slowest 10% of reaction times. These findings demonstrate that an increased body temperature, associated with and independent of internal biological time, is correlated with improved performance and alertness. These results support the hypothesis that body temperature modulates neurobehavioral function in humans.
Address (up) Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. kenneth.wright@colorado.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 0363-6119 ISBN Medium
Area Expedition Conference
Notes PMID:12388468 Approved no
Call Number LoNNe @ kagoburian @ Serial 835
Permanent link to this record
 

 
Author Rockhill, A.P.; DePerno, C.S.; Powell, R.A.
Title The effect of illumination and time of day on movements of bobcats (Lynx rufus) Type Journal Article
Year 2013 Publication PloS one Abbreviated Journal PLoS One
Volume 8 Issue 7 Pages e69213
Keywords Animals; Female; *Lighting; Lynx/*physiology; Male; Moon; Movement/*physiology; North Carolina; Time Factors; Wetlands
Abstract Understanding behavioral changes of prey and predators based on lunar illumination provides insight into important life history, behavioral ecology, and survival information. The objectives of this research were to determine if bobcat movement rates differed by period of day (dark, moon, crepuscular, day), lunar illumination (<10%, 10 – <50%, 50 – <90%, >90%), and moon phase (new, full). Bobcats had high movement rates during crepuscular and day periods and low movement rates during dark periods with highest nighttime rates at 10-<50% lunar illumination. Bobcats had highest movement rates during daytime when nighttime illumination was low (new moon) and higher movement rates during nighttime when lunar illumination was high (full moon). The behaviors we observed are consistent with prey availability being affected by light level and by limited vision by bobcats during darkness.
Address (up) Fisheries, Wildlife, and Conservation Biology, North Carolina State University, Raleigh, North Carolina, USA. aimee_rockhill@ncsu.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 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:23861963; PMCID:PMC3704646 Approved no
Call Number IDA @ john @ Serial 84
Permanent link to this record
 

 
Author Menegaux, F.; Truong, T.; Anger, A.; Cordina-Duverger, E.; Lamkarkach, F.; Arveux, P.; Kerbrat, P.; Fevotte, J.; Guenel, P.
Title Night work and breast cancer: a population-based case-control study in France (the CECILE study) Type Journal Article
Year 2013 Publication International Journal of Cancer. Journal International du Cancer Abbreviated Journal Int J Cancer
Volume 132 Issue 4 Pages 924-931
Keywords Human Health; Adult; Aged; Breast Neoplasms/epidemiology/*etiology; Case-Control Studies; *Circadian Rhythm; Employment; Female; France/epidemiology; Humans; Middle Aged; Occupations; Pregnancy; Risk Factors; *Work Schedule Tolerance
Abstract Night work involving disruption of circadian rhythm was suggested as a possible cause of breast cancer. We examined the role of night work in a large population-based case-control study carried out in France between 2005 and 2008. Lifetime occupational history including work schedules of each night work period was elicited in 1,232 cases of breast cancer and 1,317 population controls. Thirteen percent of the cases and 11% of the controls had ever worked on night shifts (OR = 1.27 [95% confidence interval = 0.99-1.64]). Odds ratios were 1.35 [1.01-1.80] in women who worked on overnight shifts, 1.40 [1.01-1.92] in women who had worked at night for 4.5 or more years, and 1.43 [1.01-2.03] in those who worked less than three nights per week on average. The odds ratio was 1.95 [1.13-3.35] in women employed in night work for >4 years before their first full-term pregnancy, a period where mammary gland cells are incompletely differentiated and possibly more susceptible to circadian disruption effects. Our results support the hypothesis that night work plays a role in breast cancer, particularly in women who started working at night before first full-term pregnancy.
Address (up) Inserm, CESP Center for research in Epidemiology and Population Health, U1018, Environmental Epidemiology of Cancer, Villejuif, France; Univ Paris-Sud, UMRS 1018, Villejuif, France
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 0020-7136 ISBN Medium
Area Expedition Conference
Notes PMID:22689255 Approved no
Call Number LoNNe @ kagoburian @ Serial 781
Permanent link to this record