Accession Number:

AD0640631

Title:

ENTRAINMENT OF CIRCADIAN RHYTHMS BY ZEITGEBERS.

Descriptive Note:

Final scientific rept.,

Corporate Author:

MAX-PLANCK-INSTITUT FUER VERHALTENSPHYSIOLOGIE ERLING-ANDECHS (WEST GERMANY)

Personal Author(s):

Report Date:

1966-09-25

Pagination or Media Count:

5.0

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

Subject Categories:

  • Anatomy and Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE