title: Sleep Propensity under Forced Desynchrony in a Model of Arousal State Dynamics.
abstract: An improvement to our current quantitative model of arousal state dynamics is presented that more accurately predicts sleep propensity as measured with sleep dynamics depending on circadian phase and prior wakefulness. A nonlinear relationship between the circadian variables within the dynamic circadian oscillator model is introduced to account for the skewed shape of the circadian rhythm of alertness that peaks just prior to the onset of the biological night (the "wake maintenance zone") and has a minimum toward the end of the biological night. The revised circadian drive thus provides a strong inhibitory input to the sleep-active neuronal population in the evening, counteracting the excitatory effects of the increased homeostatic sleep drive as originally proposed in the opponent process model of sleep-wake regulation. The revised model successfully predicts the sleep propensity profile as reflected in the dynamics of the total sleep time, sleep onset latency, wake/sleep ratio, and sleep efficiency during a wide range of experimental protocols. Specifically, all of these sleep measures are predicted for forced desynchrony schedules with day lengths ranging from 1.5 to 42.85 h and scheduled time in bed from 0.5 to 14.27 h. The revised model is expected to facilitate more accurate predictions of sleep under normal conditions as well as during circadian misalignment, for example, during shiftwork and jetlag.
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia Centre of Excellence for Integrative Brain Function, University of Sydney, New South Wales, Australia spostnova@sydney.edu.au.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Postnova
authors.affiliation: Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia Centre for Translational Sleep and Circadian Neurobiology, Monash University, Victoria, Australia.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Lockley
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia Cooperative Research Centre for Alertness, Safety, and Productivity, Melbourne, Australia Centre of Excellence for Integrative Brain Function, University of Sydney, New South Wales, Australia Centre for Translational Sleep and Circadian Neurobiology, University of Sydney, New South Wales, Australia.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Robinson
mesh_terms: D001143:Arousal; D001288:Attention; D001831:Body Temperature; D002940:Circadian Rhythm; D006706:Homeostasis; D006801:Humans; D020179:Jet Lag Syndrome; D008954:Models, Biological; D012890:Sleep; D012895:Sleep, REM; D014851:Wakefulness
keywords: circadian; circadian phase; forced desynchrony; homeostatic; modeling; sleep propensity; wake maintenance zone