The Pacemaker and its Precision

Abstract

The central hypothesis of this book invokes a “pacemaker” as the source of the wake-sleep cycle. It is a matter of definition that a pacemaker is a persistent generator of regular, rhythmic output, and so at first glance the proposition that the wake-sleep cycle of vertebrates reflects a pacemaker may seem to convey nothing more than that a rhythm of some regularity has been observed. There is, however, a critical additional implication, testable by experiment, which is that wakefulness and sleep, activity and inactivity, are not themselves essential elements in the “feedback loop” which is responsible for the observed rhythm. Applied to the human experience, it is an initially appealing hypothesis that the duration of sleep is determined only by how tired one was from the preceding day’s activity; that the duration of wakefulness is then determined by how long and soundly one has slept, and how much activity has been undertaken before being again tired enough to sleep; and that the regular sequence of these two independently timed processes might lead to the daily wake-sleep cycle. This suggestion seems to comport with our ordinary experience, but it is exactly this kind of proposition that the pacemaker concept is intended to contradict.