Spectral sensitivity of circadian phase resetting, melatonin suppression and acute alerting effects of intermittent light exposure

2021 ◽  
pp. 114504 ◽  
Author(s):  
Shadab A. Rahman ◽  
George C. Brainard ◽  
Charles A. Czeisler ◽  
Steven W. Lockley
Keyword(s):  
Spectral Sensitivity ◽  
Light Exposure ◽  
Phase Resetting ◽  
Intermittent Light ◽  
Circadian Phase ◽  
Melatonin Suppression

scholarly journals The Circadian Phase Response Curve to Light: Conservation across Seasons and Anchorage to Sunset

2021 ◽  
Author(s):  
Hannah K. Dollish ◽  
Sevag Kaladchibachi ◽  
David C. Negelspach ◽  
Fabian Fernandez
Keyword(s):  
Human Population ◽  
Phase Response Curve ◽  
Light Exposure ◽  
Phase Response ◽  
Phase Resetting ◽  
Response Curves ◽  
Light Responses ◽  
Circadian Phase ◽  
Phase Alignment ◽  
Seasonal Depression

Predictions about circadian light responses are largely based on photic phase-response curves (PRCs) generated from animals housed under seasonally agnostic equatorial photoperiods with alternating 12-hour segments of light and darkness. Most of the human population, however, lives at northerly latitudes where seasonal variations in the light-dark schedule are pronounced. Here, we address this disconnect by constructing the first high-resolution seasonal atlas for light-induced circadian phase-resetting. Testing the light responses of nearly 4,000 Drosophila at 120 timepoints across 5 seasonally relevant photoperiods, we determined that many aspects of the circadian PRC waveform are conserved with increasing daylength. Surprisingly though, irrespective of LD schedule, the start of the PRCs always remained anchored to the timing of subjective sunset, creating a differential overlap of the advance zone with the morning hours after subjective sunrise that was maximized under summer photoperiods and minimized under winter photoperiods. These data suggest that circadian photosensitivity is effectively extinguished by the early winter morning and out of optimal phase alignment with the wake schedules of many individuals. They raise the possibility that phototherapy protocols for conditions such as seasonal depression might be improved with programmed light exposure during the final hours of sleep.

Circadian Phase Resetting in Older People by Ocular Bright Light Exposure

2001 ◽  
Vol 49 (1) ◽  
pp. 30-40 ◽  
Author(s):  
E.B. Klerman ◽  
J.F. Duffy ◽  
D.-J. Dijk ◽  
C.A. Czeisler
Keyword(s):  
Older People ◽  
Light Exposure ◽  
Bright Light ◽  
Phase Resetting ◽  
Circadian Phase ◽  
Bright Light Exposure

scholarly journals Functional decoupling of melatonin suppression and circadian phase resetting in humans

2018 ◽  
Vol 596 (11) ◽  
pp. 2147-2157 ◽  
Author(s):  
Shadab A. Rahman ◽  
Melissa A. St Hilaire ◽  
Claude Gronfier ◽  
Anne-Marie Chang ◽  
Nayantara Santhi ◽  
...  
Keyword(s):  
Phase Resetting ◽  
Circadian Phase ◽  
Melatonin Suppression

scholarly journals Effect of exposure duration and light spectra on nighttime melatonin suppression in adolescents and adults

2018 ◽  
Vol 51 (4) ◽  
pp. 530-543 ◽  
Author(s):  
R Nagare ◽  
B Plitnick ◽  
MG Figueiro
Keyword(s):  
Repeated Measures ◽  
Short Wavelength ◽  
Exposure Duration ◽  
Light Exposure ◽  
Circadian Phase ◽  
Light Spectra ◽  
Melatonin Suppression ◽  
Main Effect ◽  
Adolescents And Adults ◽  
Wavelength Radiation

This study investigated how light exposure duration affects melatonin suppression, a well-established marker of circadian phase, and whether adolescents (13–18 years) are more sensitive to short-wavelength (blue) light than adults (32–51 years). Twenty-four participants (12 adolescents, 12 adults) were exposed to three lighting conditions during successive 4-h study nights that were separated by at least one week. In addition to a dim light (<5 lux) control, participants were exposed to two light spectra (warm (2700 K) and cool (5600 K)) delivering a circadian stimulus of 0.25 at eye level. Repeated measures analysis of variance revealed a significant main effect of exposure duration, indicating that a longer duration exposure suppressed melatonin to a greater degree. The analysis further revealed a significant main effect of spectrum and a significant interaction between spectrum and participant age. For the adolescents, but not the adults, melatonin suppression was significantly greater after exposure to the 5600 K intervention (43%) compared to the 2700 K intervention (29%), suggesting an increased sensitivity to short-wavelength radiation. These results will be used to extend the model of human circadian phototransduction to incorporate factors such as exposure duration and participant age to better predict effective circadian stimulus.

scholarly journals Circadian phase resetting by a single short-duration light exposure

JCI Insight ◽  
2017 ◽  
Vol 2 (7) ◽  
Author(s):  
Shadab A. Rahman ◽  
Melissa A. St. Hilaire ◽  
Anne-Marie Chang ◽  
Nayantara Santhi ◽  
Jeanne F. Duffy ◽  
...  
Keyword(s):  
Short Duration ◽  
Light Exposure ◽  
Phase Resetting ◽  
Circadian Phase

scholarly journals Comment Concerning the Effects of Light Intensity on Melatonin Suppression in the Review “Light Modulation of Human Clocks, Wake, and Sleep” by A. Prayag et al.

2021 ◽  
Vol 3 (1) ◽  
pp. 181-188
Author(s):  
Peter Bracke ◽  
Eowyn Van de Putte ◽  
Wouter R. Ryckaert
Keyword(s):  
Phase Shift ◽  
Light Intensity ◽  
Dose Response ◽  
Light Modulation ◽  
Response Curves ◽  
Practical Applications ◽  
Circadian Phase ◽  
Melatonin Suppression ◽  
Dose Response Curves ◽  
Circadian Phase Shift

Dose-response curves for circadian phase shift and melatonin suppression in relation to white or monochromatic nighttime illumination can be scaled to melanopic weighed illumination for normally constricted pupils, which makes them easier to interpret and compare. This is helpful for a practical applications.

Enhanced circadian phase resetting in R192Q Cav2.1 calcium channel migraine mice

2008 ◽  
Vol 64 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Floor van Oosterhout ◽  
Stephan Michel ◽  
Tom Deboer ◽  
Thijs Houben ◽  
Rob C. G. van de Ven ◽  
...  
Keyword(s):  
Calcium Channel ◽  
Phase Resetting ◽  
Circadian Phase

scholarly journals Rest-activity cycles and melatonin phase angle of circadian entrainment in people without cone-mediated vision

2020 ◽  
Author(s):  
Manuel Spitschan ◽  
Corrado Garbazza ◽  
Susanne Kohl ◽  
Christian Cajochen
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Activity Patterns ◽  
External World ◽  
Circadian Phase ◽  
Cone System ◽  
Retinohypothalamic Tract ◽  
Activity Cycles ◽  
Phase Angles ◽  
Rest Activity

AbstractLight is strong zeitgeber to the human circadian system, entraining internal rhythms in physiology and behaviour to the external world. This is mediated by the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), which sense light in addition to the classical photoreceptors, the cones and rods. Circadian responses depend on light intensity, with exposure to brighter light leading to bigger circadian phase shifts and melatonin suppression. In congenital achromatopsia (prevalence 1 in 30,000 to 50,000 people), the cone system is non-functional, resulting in light avoidance and photophobia at light levels which are tolerable and habitual to individuals with a normal, trichromatic retina. Here, we examined chronotype and self-reported sleep, actigraphy-derived rest-activity cycles and increases melatonin in the evening in a group of genetically confirmed congenital achromats. We found normal rest-activity patterns in all participants, and normal melatonin phase angles of entrainment in 2/3 of our participants. Our results suggest that a functional cone system and exposure to daytime light intensities are not necessary for regular behavioural and hormonal entrainment. This may point to a compensation mechanism in circadian photoreception, which in conjunction with non-photic zeitgebers, ensures synchronisation of activity to the external world.Significance statementRhythms in physiology and behaviour are synchronised to the external cycle of light exposure. This is mediated by the retinohypothalamic tract, which connects the photoreceptors in the eye with the “circadian pacemaker” in our brain, the suprachiasmatic nucleus. What happens to our circadian rhythm when we lack the cone photoreceptors in the eye that enable us to see in daylight? We examined this question in a group of rare congenital achromats. Our work reveals that normal rhythms in rest and activity, and production of hormones, does not require a functional cone system.

scholarly journals Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

2020 ◽  
Vol 35 (4) ◽  
pp. 405-415 ◽  
Author(s):  
Martin Moore-Ede ◽  
Anneke Heitmann ◽  
Rainer Guttkuhn
Keyword(s):  
Spectral Sensitivity ◽  
White Light ◽  
Light Exposure ◽  
Human Subjects ◽  
Light Sources ◽  
Led Light ◽  
Light Spectra ◽  
Timing System ◽  
Circadian Timing System ◽  
Spectral Sensitivity Curve

Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.

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