Sleep homeostasis in the rat: simulation of the time course of EEG slow-wave activity

Neurosci Lett. 1991 Sep 16;130(2):141-4. doi: 10.1016/0304-3940(91)90382-4.


According to the two-process model of sleep regulation, a homeostatic Process S increases during waking and declines during sleep. For humans, the time course of S has been derived from the changes in EEG slow-wave activity (SWA; spectral power density in the 0.75-4.0 Hz range) during sleep. We tested the applicability of the model to sleep in the rat. The simulation was based on the vigilance states for consecutive 8-s epochs of a 96-h experiment in 9 animals. The level of S was made to decrease in epochs of non-REM sleep (NREMS), and to increase in epochs of waking or REM sleep according to exponential functions. By optimizing the initial value and the time constants of S, a close fit between the hourly values of SWA in NREMS and of S was obtained. The biphasic time course of SWA during baseline, its enhancement in the initial recovery period after 24-h sleep deprivation, and its subsequent prolonged undershoot were present in the simulation. We conclude that sleep homeostasis as conceptualized in the two-process model may be a general property of mammalian sleep.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Electroencephalography
  • Homeostasis
  • Male
  • Models, Biological
  • Rats / physiology*
  • Sleep / physiology*
  • Sleep Deprivation / physiology
  • Sleep Stages / physiology