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Séminaire impromptu - Charles Czeisler"Neurobiology of the human circadian pacemaker: Impact of environmental light on population health and safety"

Abstract :

Spécialiste en chronobiologie, Université de Boston
Division of Sleep Medecine Harward Medicale School

My laboratory research is focused on understanding the neurobiology of the human circadian pacemaker, located in the suprachiasmatic nucleus (SCN) of the hypothalamus, and its interaction with the sleep homeostat, and on applying that knowledge to clinical medicine and occupational health. We are examining the role of the pineal hormone melatonin in the organization of sleep and circadian rhythms. We are investigating the physiological mechanism underlying photic resetting of the human circadian pacemaker, having shown that some blind people without sight can retain normal circadian responsiveness to light. We are now investigating how the timing, duration, intensity and wavelength of light affects its circadian resetting capacity, which is mediated through intrinsically photosensitive retinal ganglion cells containing the novel photopigment melanopsin. Current research is aimed at functional determination of the photoreceptor(s) responsible for circadian vision in humans, on adaptation of circadian photoreceptors and on the after-effects of entrainment on circadian period in humans. We are investigating how circadian and homeostatic processes interact to regulate sleep and neurobiological function during wakefulness. Other ongoing research in the lab includes examining novel wakefulness- and sleep-promoting countermeasures, the effect of exercise on the circadian pacemaker, fMRI of the sleep deprived brain, the influence of aging on sleep and circadian rhythms, the influence of chronic sleep restriction on human performance, the influence of space flight on sleep and circadian rhythms and the application of our research to night workers-including medical residents and police-through the work of the Harvard Work Hours, Health and Safety Group.

Selected publications

Last publications

Sleep Duration in Midlife and Later Life in Relation to Cognition.
Devore EE, Grodstein F, Duffy JF, Stampfer MJ, Czeisler CA, Schernhammer ES.
J Am Geriatr Soc. 2014 May 1. doi: 10.1111/jgs.12790. [Epub ahead of print]

Diurnal spectral sensitivity of the acute alerting effects of light.
Rahman SA, Flynn-Evans EE, Aeschbach D, Brainard GC, Czeisler CA, Lockley SW.
Sleep. 2014 Feb 1;37(2):271-81. doi: 10.5665/sleep.3396.

Absence of Central Circadian Pacemaker Abnormalities in Humans With Loss of Function Mutation in Prokineticin 2.
Balasubramanian R, Cohen DA, Klerman EB, Pignatelli D, Hall JE, Dwyer AA, Czeisler CA, Pitteloud N, Crowley WF Jr.
J Clin Endocrinol Metab. 2014 Jan 1:jc20132096. [Epub ahead of print]

The sleep and technology use of Americans: findings from the National Sleep Foundation's 2011 Sleep in America poll.
Gradisar M, Wolfson AR, Harvey AG, Hale L, Rosenberg R, Czeisler CA.
J Clin Sleep Med. 2013 Dec 15;9(12):1291-9. doi: 10.5664/jcsm.3272.

 Measuring and using light in the melanopsin age.

Lucas RJ, Peirson SN, Berson DM, Brown TM, Cooper HM, Czeisler CA, Figueiro MG, Gamlin PD, Lockley SW, O'Hagan JB, Price LL, Provencio I, Skene DJ, Brainard GC.
Trends Neurosci. 2014 Jan;37(1):1-9. doi: 10.1016/j.tins.2013.10.004. Epub 2013 Nov 25.

Assessment of drowsiness based on ocular parameters detected by infrared reflectance oculography.
Anderson C, Chang AM, Sullivan JP, Ronda JM, Czeisler CA.
J Clin Sleep Med. 2013 Sep;9(9):907-20, 920A-920B. doi: 10.5664/jcsm.2992.

Scientific focus :

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