AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 6 1033-R1036, Copyright © 1986 by American Physiological Society
Further discussion of a model of the REM sleep oscillator
R. W. McCarley and S. G. Massaquoi
The limit cycle feature and the grounding of our model in physiology are
endorsed by Daan and Beersma [Am. J. Physiol. 251 (Regulatory Integrative
Comp. Physiol. 20): R1030-R1032, 1986.] as well as the fundamental
postulate of the model that the latency, duration, and intensity of the
first rapid-eye-movement (REM) period depends on whether the limit cycle is
entered from an internal or external trajectory, and the fact that this
trajectory is determined by circadian modulation of conditions at sleep
onset. We describe our reasons for preferring a more explicit formulation
of the sleep onset conditions than provided in our earlier "Karma" version
of this model and provide additional details of how the control of the
REM-off population decline is modeled. Additional empirical evidence is
cited for the continuous circadian modulation of REM cycle parameters. We
emphasize that, compared with the original simple model, the present
version of the model adds only one additional "free" initial condition
parameter (circadian phase) that is used to model normal sleep begun at
different circadian phases and the resultant variations in REM latency,
duration, intensity, and period length. We present specific predictions of
the model and new supporting empirical data.
