Circadian Periodicity in Primates under Various Light - Dark Ratios.
DELAWARE UNIV NEWARK
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The activity of four rhesus monkeys Macaca mulatta was recorded for the purpose of appraising the effects of different light-dark LD ratios upon circadian periodicity. Light-dark cycle was automatically scheduled, and temperature was held constant. Three LD ratios 1212, 618, and 186 were used. Consistent differential effects upon shape and amplitude of the circadian period, associated with the different LD ratios, were observed. A high degree of photoperiodic dependency was demonstrated under the LD 186 schedule. Activity onset and cessation closely followed the onset and termination of the light period. A lesser degree of photoperiodic dependency was manifested by the LD 618 schedule, with activity starting 3-4 hours before the onset of light. Author
- Anatomy and Physiology