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Abstractor: D.M. Bowden, 1969
SUMMARY
Three adolescent male baboons were trained to press a bar in response to a bell or a light to receive food, and not to press in response to a tone. This simple conditioning paradigm was repeated more than 1,000 times until the subjects responded correctly no matter what time of day or night, despite the presence of strange people in the test chamber, and after interruptions in the testing schedule lasting as long as 30 days, thus illustrating the stability of the acquired responses. During this phase of the experiment the subjects were also tested for baseline levels and diurnal variations in motor activity, body temperature, blood pressure (BP), and electrocardiogram (EKG).
Once performance was stable and the baseline data had been established, the animals were subjected to a stressor condition in which the normal 12-hour light/ 12-hour dark cycle (12L-12D) was replaced by a succession of cycles, such as 6L-6D or 24D-24L, and feeding times were irregular. Each time the diurnal records indicated that the subject's activity rhythm was becoming entrained to a new cycle, the cycle was altered. The subjects were studied for 10 weeks under the stressor condition and for 6 to 16 weeks after cessation of the stressor condition.
All subjects showed disruption of the CRS within 12 days after onset of the stressor condition. They did not respond to the CSs when tested at night, and one
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