Behavioral biology最新文献

Literature on “imprinting,” a process whereby social preferences are presumably “stamped in” as a result of exposure during a very brief sensitive or critical period, is voluminous, yet much of it may have little relationship to social attachment processes. Domestic chicks remain responsive to biologically appropriate stimuli for several days posthatching and do not exhibit behavior which suggests that they learn to prefer to socialize with objects to which they have earlier been trained regardless of when they were exposed. Social attachment processes are of huge evolutionary and ontogenetic significance; imprinting, as it is usually defined and measured, may not reflect social attachment.

Stereotypic behaviors emitted by Mongolian gerbils given large acute doses of amphetamine are similar to analogous behaviors in other species in being repetitive, compulsive units of motor behavior. Qualitative and quantitative descriptions are used to emphasize the interspecies and intraspecies differences in the particular behaviors emitted. The behaviors observed before injection were not predictive of the stereotypies induced by amphetamine. One consistent change in behavior following amphetamine was the change from normal social behavior to social stereotypy, suggesting that the gerbil, a very social animal, may be useful for studying central mechanisms of social behavior.

Posttrial epinephrine injections can enhance or impair later retention performance of inhibitory (passive) avoidance training in rats. The findings reported here indicate that the effects on retention of epinephrine injections and of footshock level are closely related to transient posttraining decreases in whole brain norepinephrine concentrations. Posttraining norepinephrine levels, as measured 10 min after training and treatment, predict the later retention performance of groups of rats trained with high or low footshock and, in addition, predict the retroactive effects (enhancement or impairment) of posttrial epinephrine injections. These findings are consistent with the view that hormonal responses to training may modulate memory storage processing. In addition, the results suggest that memory modulation may involve neuroendocrine mechanisms that include the central noradrenergic system.

Changes in sleeping distances in 11 pairs of wild wolves (Canis lupus) were studied to determine if they correlated with stages of the breeding cycle. Aerial radio-tracking and observation were the techniques used. Members of most pairs slept less than 1 m apart at least sometime during proestrus and the first half of the breeding season, but slept farther apart during the second half and after breeding. These changes might be related to differences in serum estrogen levels.

Nocturnal gastric contraction periods were recorded in three subjects using stomach balloons and in four subjects using open catheters. In every subject, gastric contractions occurred cyclically about every 100 min. Gastric contraction cycles had no relationship to the EEG sleep stages or to REM—NONREM sleep cycles.

Exploration by hooded rats of two stimuli differing in complexity was investigated as a function of lesion location, preexposure complexity, and preexposure time over three successive 10-min periods. Results indicated the preexposure complexity altered the total number of exploratory responses of both lesioned and normal animals as a function of test stimulus complexity. Significant habituation rate differences were found between normal and operated animals, with similar effects occurring between cortical control and hippocampally damaged animals with one stimulus. There were no significant behavioral differences between animals receiving dorsal or ventral hippocampal lesions for the paradigm employed. Approaches to an area illuminated as the stimulus area, but containing no stimuli, revealed apparent light-dependent response decrements in the hippocampally lesioned animals. These results suggest that hippocampally lesioned animals and, in some instances, cortically lesioned animals, cannot rapidly shift certain modes of response even though the necessary information has been acquired and can be evidenced when different response constraints are imposed.

Four-day-old Vantress × Arbor Acre chicks injected intraperitoneally with scopolamine hydrobromide increased their activity in an open arena, were more resistant to extinction after key-peck conditioning, and were disrupted in passive avoidance learning when compared to saline-injected controls. Also, the young chicks' performance on these three tests of “behavioral inhibition” was differentially sensitive to the effects of scopolamine. Scopolamine, 1 mg/kg, increased the chicks' activity by about 100% and produced greater resistance to extinction, but had no significant effect on passive avoidance learning. Scopolamine, 4 mg/kg, also increased the chicks' activity by about 100%, but disrupted key—peck performance during extinction testing and significantly reduced response suppression in the key-peck passive avoidance test. Scopolamine, therefore, affects the young precocial chicks' performance on three tasks that have been assumed to measure inhibitory behavior, results that are consistent with the effects of cholinergic antagonists on inhibitory behavior of the altricial rat.

The pecking and peeping behavior of isolate, pair- and group-reared chicks tested singly with and without mirrors were studied during 2-hr tests. Results supported the hypothesis that the social facilitation of pecking is disrupted by test novelty (discrepancy between testing and rearing conditions). Mirror exposure resulted in the greatest enhancement of pecking and least peeping in pair-reared chicks and in more moderate pecking increases and more peeping in group-reared chicks. Isolates initially avoided mirrors but after an hour peeped less and showed a social facilitation of pecking.

Experiment 1 assessed the percentage of 4.0, 6.0, and 8.0% NaCl solution ingested by gerbils when they were given a choice between one of these saline solutions and water. The gerbils showed a uniformly low level of acceptance of these hypertonic solutions. When given a choice between 4.0 and 8.0% NaCl (Expt 2), the gerbils showed a preference for 4.0% saline. Experiment 3 evaluated the effects of Aldactazide on the gerbils' intake of 6.0% NaCl solution. The results indicated that relative to intake before and after the injection days, the gerbils showed a significant increase in saline intake. Experiment 4 examined the effects of DOCA injections on the gerbils' intake of 6.0% NaCl. The effects were dose-related. Injections of 5 mg of DOCA significantly increased the gerbils' saline intake while injections of 1 mg of the mineralocorticoid had no effect.