Duration invariance and intensity dependence of the human circadian system phase shifting response to brief light flashes
Article
Article Title | Duration invariance and intensity dependence of the human circadian system phase shifting response to brief light flashes |
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ERA Journal ID | 2111 |
Article Category | Article |
Authors | Joyce, Daniel S., Spitschan, Manuel and Zeitzer, Jamie M. |
Journal Title | Proceedings of the Royal Society B: Biological Sciences |
Journal Citation | 289 (1970), pp. 1-10 |
Number of Pages | 10 |
Year | 2022 |
Publisher | Royal Society Publishing |
Place of Publication | United Kingdom |
ISSN | 0962-8452 |
1471-2954 | |
Digital Object Identifier (DOI) | https://doi.org/10.1098/rspb.2021.1943 |
Web Address (URL) | https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1943 |
Abstract | The melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are characterized by a delayed off-time following the cessation of light stimulation. Here, we exploited this unusual physiologic property to characterize the exquisite sensitivity of the human circadian system to flashed light. In a 34 h in-laboratory between-subjects design, we examined phase shifting in response to variable-intensity (3-9500 photopic lux) flashes at fixed duration (2 ms; n = 28 participants) and variable-duration (10 s- 10 s) flashes at fixed intensity (2000 photopic lux; n = 31 participants). Acute melatonin suppression, objective alertness and subjective sleepiness during the flash sequence were also assessed. We find a dose-response relationship between flash intensity and circadian phase shift, with an indication of a possible threshold-like behaviour. We find a slight parametric relationship between flash duration and circadian phase shift. Consistent with prior studies, we observe no dose-response relationship to either flash intensity or duration and the acute impact of light on melatonin suppression, objective alertness or subjective sleepiness. Our findings are consistent with circadian responses to a sequence of flashes being mediated by rod or cone photoreceptors via ipRGC integration. |
Keywords | alertness; circadian; light; melatonin; sleep; flash |
ANZSRC Field of Research 2020 | 520406. Sensory processes, perception and performance |
520206. Psychophysiology | |
Byline Affiliations | Stanford University, United States |
VA Palo Alto Health Care System, United States | |
Technical University of Munich, Germany | |
Max Planck Society, Germany |
https://research.usq.edu.au/item/w3v24/duration-invariance-and-intensity-dependence-of-the-human-circadian-system-phase-shifting-response-to-brief-light-flashes
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