Activity cycles of the rhesus monkey (Macaca mulatta) under several experimental conditions, both in isolation and in a group situation
Titel:
Activity cycles of the rhesus monkey (Macaca mulatta) under several experimental conditions, both in isolation and in a group situation
Auteur:
Yellin, A. M. Hauty, G. T.
Verschenen in:
Biological rhythm research
Paginering:
Jaargang 2 (1971) nr. 4 pagina's 475-490
Jaar:
1971-12
Inhoud:
Rhesus monkeys (Macaca mulatta) were subjected to several, successively applied, environmental conditions. Their activity was monitored by means of ultra-sonic movement detectors, and the data were submitted to a least sqares spectral analysis. Under a rigidly enforced external cycle of twelve hours of light followed by twelve hours of dark (L/D 12/12 the individually isolated monkeys exhibited great photoperiodic dependency and a very consistent activity pattern, with the peak occurring shortly after light onset. In constant light (L/L) there were individual differences in the rate of which the activity patterns changed from those exhibited under the L/D 12/12 condition. The modifications included, in addition to changes in circadian frequency, a rise in the activity level during hte rest period and shifts in the location of the peak of the daily activity curve relative to its onset. Under self-regulated exposure to light and dark (L/D-Sl1) the isolated monkeys' activity patterns became highly irregular, and there were indications of a tendency for circadian periodicity to disappear under prolonged exposure to this condition. Mutual entrainment was clearly apparent in a group condition where each subject could independently control the lighting of the colony room (L/D-SG). There were indications that dominance played some role in the group entrainment. The activity curves under this condition resembled the pattern observed under the L/D 12/12 regimen. The last condition, which was similar to the L/D-S11] condition (L/D-S12) provided added proof for the mutual entrainment observed under the previous group condition. The newly isolated subjects all began to “free-run” from the same point in time. This condition also demonstrated the effects of previous environmental conditions on a current one. The computer analysis also indicated frequencies other than circadian. Under the group condition there was very close correspondence in time of peaking of these periodicities across all the subjects. This provided added proof for the social entrainment in the group situation.
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