title: Slow-wave sleep in daytime and nocturnal sleep: an estimate of the time course of "Process S".
abstract: Daan et al. (1984) have proposed that sleep and wakefulness are regulated, in part, by a "Process S" that increases during wakefulness and declines during sleep. Data derived from several studies were taken to determine the time course of Process S during both wakefulness and sleep. As required by the model, slow-wave-sleep (SWS; an index of Process S) was found to increase exponentially as a function of prior wake time (equation 1) and to decline exponentially as a function of time asleep (equation 2). The equations accounted for 91% and 96% of the variance, respectively. In addition, equation 1 accurately predicted the amount the amount of SWS in the first hour of nocturnal sleep.
authors.affiliation: Department of Psychology, Queen's University, Kingston, Ontario, Canada.
authors.forename: J B
authors.initials: JB
authors.lastname: Knowles
authors.forename: A W
authors.initials: AW
authors.lastname: MacLean
authors.forename: L
authors.initials: L
authors.lastname: Salem
authors.forename: C
authors.initials: C
authors.lastname: Vetere
authors.forename: M
authors.initials: M
authors.lastname: Coulter
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology