ENTRAINMENT OF CIRCADIAN RHYTHMS BY ZEITGEBERS.
Abstract
The results of five different types of experiments can be summarized as follows: (1) The phase-angle difference between the circadian rhythm and the entraining Zeitgeber is a function of the free-running circadian period as measured under constant conditions. (2) Circadian activity rhythms of birds, kept in konstant dim illumination, can be entrained by species-specific song cycles, demonstrating the existence of 'social Zeitgebers'. (3) The duration of twilight is one of the factors determining the phase-angle difference between the circadian rhythm and the entraining light-dark cycle. (4) Calculations with a model equation for circadian rhythms indicate that the duration of re-entrainment of a circadian rhythm after a phase-shift of the Zeitgeber depends (a) on the natural circadian period and (b) on the direction of the shift. (5) The theoretical predictions concerning the duration of re-entrainment after phase-shifts of the Zeitgeber have been confirmed in experiments with animals as well as with human subjects. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 25, 1966
- Accession Number
- AD0640631
Entities
People
- Juergen Aschoff