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Human phase response curve to a single 6.5 h pulse of short-wavelength light

Rüger, M., St Hilaire, M.A., Brainard, G.C., Khalsa, S.-B.S., Kronauer, R.E., Czeisler, C.A. and Lockley, S.W. (2013) Human phase response curve to a single 6.5 h pulse of short-wavelength light Journal of Physiology, 591 (1). pp. 353-363.

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The photic resetting response of the human circadian pacemaker depends on the timing of exposure, and the direction and magnitude of the resulting shift is described by a phase response curve (PRC). Previous PRCs in humans have utilized high-intensity polychromatic white light. Given that the circadian photoreception system is maximally sensitive to short-wavelength visible light, the aim of the current study was to construct a PRC to blue (480 nm) light and compare it to a 10,000 lux white light PRC constructed previously using a similar protocol. Eighteen young healthy participants (18-30 years) were studied for 9-10 days in a time-free environment. The protocol included three baseline days followed by a constant routine (CR) to assess initial circadian phase. Following this CR, participants were exposed to a 6.5 h 480 nm light exposure (11.8 μW cm-2, 11.2 lux) following mydriasis via a modified Ganzfeld dome. A second CR was conducted following the light exposure to re-assess circadian phase. Phase shifts were calculated from the difference in dim light melatonin onset (DLMO) between CRs. Exposure to 6.5 h of 480 nm light resets the circadian pacemaker according to a conventional type 1 PRC with fitted maximum delays and advances of -2.6 h and 1.3 h, respectively. The 480 nm PRC induced �75% of the response of the 10,000 lux white light PRC. These results may contribute to a re-evaluation of dosing guidelines for clinical light therapy and the use of light as a fatigue countermeasure. © 2012 The Physiological Society.

Item Type: Article
Authors :
Rüger, M.
St Hilaire, M.A.
Brainard, G.C.
Khalsa, S.-B.S.
Kronauer, R.E.
Czeisler, C.A.
Date : 2013
DOI : 10.1113/jphysiol.2012.239046
Uncontrolled Keywords : melanopsin, melatonin, adult, amplitude modulation, article, blue light, circadian rhythm, core temperature, evoked visual response, female, hormone synthesis, human, human experiment, light dark cycle, light exposure, light intensity, male, mydriasis, normal human, phase response curve, photoreceptor potential, priority journal, sensory system parameters, visual stimulation, white light, Adolescent, Adult, Body Temperature, Circadian Rhythm, Female, Humans, Light, Male, Melatonin, Young Adult
Depositing User : Clive Harris
Date Deposited : 17 Jun 2020 01:33
Last Modified : 17 Jun 2020 01:33

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