Entrainment of the Human Circadian System by Light

@article{Duffy2005EntrainmentOT,
  title={Entrainment of the Human Circadian System by Light},
  author={Jeanne F. Duffy and Kenneth P. Wright},
  journal={Journal of Biological Rhythms},
  year={2005},
  volume={20},
  pages={326 - 338}
}
  • J. Duffy, K. Wright
  • Published 1 August 2005
  • Biology, Psychology
  • Journal of Biological Rhythms
The periodic light-dark cycle is the dominant environmental synchronizer used by humans to entrain to the geophysical 24-h day. Entrainment is a fundamental property of circadian systems by which the period of the internal clock (τ) is synchronized to the period of the entraining stimuli (T cycle). An important aspect of entrainment in humans is the maintenance of an appropriate phase relationship between the circadian system, the timing of sleep and wakefulness, and environmental time (a.k.a… 

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TLDR
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1
2
3
4
5
...

References

SHOWING 1-10 OF 106 REFERENCES
Intrinsic Period and Light Intensity Determine the Phase Relationship between Melatonin and Sleep in Humans
TLDR
It is demonstrated that neurobiological and environmental factors interact to regulate the phase angle of entrainment in humans and has important implications for understanding physiological organization by the brain’s master circadian clock and may have implications forUnderstanding mechanisms underlying circadian sleep disorders.
Intrinsic near-24-h pacemaker period determines limits of circadian entrainment to a weak synchronizer in humans
TLDR
It is reported here that imposition of a sleep–wake schedule with exposure to the equivalent of candlelight during wakefulness and darkness during sleep is usually sufficient to maintain circadian entrainment to the 24-h day but not to a 23.5- or 24.6-H day.
Bright light affects human circadian rhythms
TLDR
It is found that bright light has an effect on the human circadian system which is qualitatively different from that of dim light, and which is similar to the effect of light in most animal experiments.
[Non-photic entrainment of human circadian clock--effects of forced sleep-wake schedule on the circadian rhythm in plasma melatonin].
  • K. Nakamura
  • Biology, Psychology
    [Hokkaido igaku zasshi] The Hokkaido journal of medical science
  • 1996
TLDR
It is concluded that the non-photic entrainment is operating in the human circadian clock, which supports the two self-sustained oscillator hypothesis.
Characteristics and Variability in Entrainment of Circadian Rhythms to Light in Diurnal Rodents
  • H. Pohl
  • Biology, Environmental Science
  • 1982
TLDR
In a comparative analysis of functional aspects of circadian pacemakers in four species of nocturnal rodents, Pittendrigh and Daan have shown that various pacemaker properties, such as the stability of the period, the shape of the phase response curve (PRC), the light-dependence of τ, and the ranges of entrainment to light cycles, vary interdependently.
Nonphotic Entrainment in Humans?
TLDR
The available evidence indicates that it remains worthwhile to continue to study nonphotic effects on human circadian timing to identify treatment strategies for shift workers and transmeridian travelers as well as for the blind and possibly the elderly.
Phase‐shifting human circadian rhythms: influence of sleep timing, social contact and light exposure.
TLDR
The data indicate that interventions designed to phase shift human circadian rhythms for adjustment to time zone changes or altered work schedules should focus on properly timed light exposure, and support the concept that the light‐dark cycle is the most important synchronizer of the human circadian system.
Light Effects on Human Circadian Rhythms: A Review of Recent Andechs Experiments
  • R. Wever
  • Biology, Psychology
    Journal of biological rhythms
  • 1989
TLDR
Since the hormone melatonin is often assumed to be involved in the generation and control of circadian rhythmicity, changes in melatonin secretion are discussed and preliminary results from experiments with administration of melatonin to humans are presented.
The effect of activity on the waking temperature rhythm in humans.
TLDR
Nine healthy female subjects studied when exposed to the natural light-dark cycle, forced desynchronization between the sleep/activity cycle and the endogenous circadian temperature rhythm took place, resulting in a further method for removing masking effects from circadianTemperature rhythm data in order to assess its endogenous component.
Photic Resetting of the Human Circadian Pacemaker in the Absence of Conscious Vision
TLDR
Light can affect the circadian pacemaker of some totally blind individuals— either by altering the phase of the circadianpacemaker or by affecting its amplitude, consistent with data from animal studies demonstrating that there are different neural pathways and retinal cells that relay photic information to the brain.
...
1
2
3
4
5
...