University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Human phase response curve to a 1 h pulse of bright white light

St Hilaire, M.A., Gooley, J.J., Khalsa, S.B.S., Kronauer, R.E., Czeisler, C.A. and Lockley, S.W. (2012) Human phase response curve to a 1 h pulse of bright white light Journal of Physiology, 590 (13). pp. 3035-3045.

Full text not available from this repository.


The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (~8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or <3 lux dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ~40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration-response function for the effects of light on circadian resetting. © 2012 The Authors. The Journal of Physiology © 2012 The Physiological Society.

Item Type: Article
Authors :
St Hilaire, M.A.
Gooley, J.J.
Khalsa, S.B.S.
Kronauer, R.E.
Czeisler, C.A.
Date : 2012
DOI : 10.1113/jphysiol.2012.227892
Uncontrolled Keywords : melatonin, adult, article, case report, circadian rhythm, controlled study, female, human, light dark cycle, light exposure, male, normal human, phase response curve, priority journal, white light, Adolescent, Adult, Circadian Rhythm, Female, Humans, Light, Male, Melatonin, Young Adult
Depositing User : Clive Harris
Date Deposited : 17 Jun 2020 01:40
Last Modified : 17 Jun 2020 01:40

Actions (login required)

View Item View Item


Downloads per month over past year

Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800