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Little is known about how frequent, acute stressors affect wild animals. We present two experiments conducted on captive, Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii) that explore how frequent, acute doses of corticosterone (CORT) affect condition and behavior. CORT was administered either once or three times a day to birds in(More)
A typical CNV paradigm, with food as reward, evokes in the squirrel monkey's post-arcuate and post-central cortices both M-waves in response to the cues and what appears to be a CNV in the interstimulus interval. Both wave forms appear to be generated locally in cortex and to be more closely related temporally to the cues than to the animal's behavioral(More)
Our knowledge of glucocorticoid actions in vertebrates comes primarily from laboratory studies, which are often conducted with little consideration of how animals experience changes in glucocorticoid secretion in natural contexts. Typically, free-living animals are exposed to acute perturbations of the environment, ranging from a few minutes to a few hours(More)
A surface-negative wave, evoked by tone cues, appeared in monkey post-arcuate cortex as the monkey learned that the cue signaled the availability of reward. This evoked activity was depressed, concomitantly with changes in the animal's behavioral responding, by doses of delta9-tetrahydrocannabinol (delta9-THC) as low as 0.032 mg/kg and of pentobarbital as(More)
The effects of low doses of nabilone, chlorpromazine, pentobarbital, meprobamate, diazepam, chlordiazepoxiOde and d-amphetamine on behavioral responding to cues signalling the availability of food rewards, and on the M-wave, an evoked cortical potential previously reported to reflect the conditioned incentive value of the cues were determined in the(More)
It was shown that the late negative wave evoked in squirrel monkey cortex by tone cues signalling the availability of reward was smaller when the animal did not respond to the cue and often disappeared if the animal ignored many cues in succession. It decreased in amplitude as a test session progressed, and the rate of this decrease increased if the rate of(More)
Typical M-waves and CNVs were produced in squirrel monkey frontal and rostral parietal cortex by light cues, as well as by tone cues. With light cues, M-waves were about 50% as large as with tone cues, whereas CNVs were of about the same magnitude with either type of cue. Typical M-waves and CNVs were also produced when avoidance of tail-shock was(More)
Changing animals from a schedule on which they had to bar-press after a tone cue to get a food pellet, to a schedule on which the food pellet was presented automatically after the tone cue and the manipulandum was not available, had no effect on the latency, amplitude, or shape of the M-wave evoked by the tone cue. The amplitude of the evoked wave did,(More)