title: Modelling sleep propensity-a need for rethinking.
abstract: The present paper reviews some of the evidence for noncircadian control of sleep propensity. It is argued that in order to account for the accumulated evidence there is a need for redefinition of some of the assumptions regarding the underlying regulation of sleep propensity. It is proposed that rapid ultradian variations in sleep propensity evolved in order to maximize the flexibility of the sleep/wake regulatory mechanism.
authors.affiliation: Sleep Laboratory, Faculty of Medicine, Technion-Israel Institute of Technology.
authors.initials: P
authors.lastname: Lavie