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Spontaneously occurring abnormal behaviors in animals have recently received considerable attention, both in veterinary medicine and as a potential model for abnormal behavior in several human mental disorders. Stereotypies are abnormal repetitive, unvarying, and functionless behaviors that are often performed by captive and domesticated animals housed in barren environments. They closely resemble the stereotypies of autistic and mentally retarded patients, stereotypies of unmedicated chronic schizophrenic patients, certain classes of simple tic in Tourette's syndrome, and several drug-induced behaviors. However, evidence for a common mechanism has been lacking. Stereotypies in human mental disorders are indicative of profound brain dysfunction involving the basal ganglia, and are associated with pervasive voluntary-motor impairments and psychological distress. Here we show that stereotypy in captive Orange-Wing Amazon Parrots (Amazona amazonica) is correlated with poor performance on the same psychiatric task (the 'gambling task') as stereotypy in autistic and schizophrenic patients. The task measures recurrent perseveration-the tendency to inappropriately repeat responses. Thus, the more stereotypy a parrot performed, the more likely it was to inappropriately repeat itself from trial-to-trial on the task; and the more rapidly it made repeated, but not switched, responses. These results parallel the executive motor impairments seen in human patients, and therefore suggest that, like in human patients, stereotypy in caged parrots reflects a general disinhibition of the behavioral control mechanisms of the dorsal basal ganglia. If this result holds true in other laboratory species, stereotypic animals are likely to be of questionable utility in behavior, neuroscience, and neuropharmacological experiments. In humans, stereotypies and obsessive-compulsive behaviors are considered to be mutually exclusive categories of behavior, with different neural substrates, and different treatment strategies. These results, therefore, suggest that the pharmacological treatment of stereotypies in veterinary medicine based on the assumption that they are equivalent to human Obsessive-Compulsive Disorder may be inappropriate. As stereotypies in captive animals develop in response to the captive environment, these results also emphasize the role that the environment may play in eliciting or exacerbating stereotypy in human patients. Finally, by parallel to human patients, there is a potential psychological distress in animals showing these behaviors.

It has been suggested that isolation from conspecifics may contribute to the development of abnormal behaviors that are common in captive parrots, including stereotypy, feather plucking, excessive fearfulness and aggression (e.g. [Proceedings of the European Symposium on Bird Diseases, Beerse, Belgium (1987), p. 98; Kleintierpraxis 38 (1993) 511]). Thus, we assessed the influence of isosexual pair housing on the development of these behaviors, as well as the incidence of illness and injury, in young Orange-winged Amazon parrots (Amazona amazonica). Parrots (n=21) were parent raised to 6 months of age and then housed either singly or in isosexual pairs. All cages included inanimate enrichments that were changed regularly, and all parrots were handled regularly. Behavioral activity was recorded 0,3,6,9 and 12 months after the parrots were housed in the experimental cages, and responses (e.g. willingness to approach, tolerance to touch, flight distance) to familiar and strange human handlers and to novel objects introduced into the home cage were recorded periodically. Paired parrots used their enrichments more (GLM: F1,10=13.74; P=0.004), and spent less time screaming (F1,10=4.90; P=0.051), less time preening (F1,10=5.12; P=0.047), and less time inactive (F1,10=9.24; P

Although many authors have suggested that the quality of the cage environment contributes to the development and performance of psychogenic feather picking by parrots, there is little scientific evidence for this relationship. In chickens, there is an established relationship between absence of foraging opportunity and the performance of a similar behavior, feather pecking. Thus, we assessed whether providing environmental enrichments designed to facilitate foraging behaviors would prevent or reduce the development of feather picking behavior by parrots, as evidenced by superior feather condition. Two groups of eight parrots were parent-reared to weaning and then housed singly in either enriched or unenriched cages for 48 weeks. In the enriched condition, a unique combination of one foraging and one physical enrichment was presented to each parrot weekly. In both groups, feather condition was quantified using a 10-point scale. The provision of enrichments led to an improvement in feather condition over 48 weeks in the enriched group, while feather scores in the control group decreased significantly (repeated measures GLM: F 1,46 =5.59; P =0.022) during this same period, indicating that feather picking behavior had developed in this group. In the second part of this study, the control group was transferred to the enriched treatment for a period of 16 weeks. During this period re-feathering occurred and feather scores improved significantly, indicating that feather picking behavior had decreased (repeated measures GLM: F 1,53 =35.57, P

The development of techniques to reduce fear responses of captive animals is important because fear is generally considered an undesirable emotional state that is related to increased risk of injury and decreased biological functioning. We tested the effects of environmental enrichments designed to increase the physical complexity of the cage and to provide opportunities for foraging behaviors on responses to novelty of young Orange-winged Amazon parrots (Amazona amazonica). Parrots (n ¼ 16) were housed in either barren or enriched conditions for 1 year and responses to novel objects and human handlers were tested periodically. Parrots in the enriched condition had significantly shorter latencies to approach novel objects placed in their home cages than parrots from the control group (repeated measures GLM: F1;13 ¼ 8:00; P ¼ 0:014). In addition, parrots from the enriched condition had shorter bouts of interaction (F1;14 ¼ 27:93; P < 0:0005) and spent significantly less time interacting with novel objects overall (F1;14 ¼ 27:93; P < 0:0005). Taken together, these results suggest that enrichment reduced both the fear response to novel objects and the motivation to explore and interact with those objects. When tested with a familiar handler, the control parrots had significantly higher response scores (i.e. they were less aggressive and more interactive) than the parrots from the enriched group (t-test; P < 0:005). This suggests that parrots housed in barren conditions may be more motivated to interact with familiar humans as a source of environmental stimulation. All parrots showed higher response scores to familiar than unfamiliar handlers, but in the control group there was a significant drop in score from the familiar to the unfamiliar handler (t-test; P < 0:0005) while in the enriched group the scores with familiar and unfamiliar handlers were similar. Thus, environmental enrichment reduced fear responses to both novel objects and unfamiliar human handlers. Factor analysis revealed that the responses to the novel object and novel human tests were independent, which implies that they did not measure the same underlying factor. Similarly, the

Stereotypies are abnormal repetitive behaviors that often develop in animals housed in impoverished environments. Stereotypy represents the interaction of several complex developmental phenomena. To characterize the temporal nature of stereotypy increase (escalation) and decrease (attenuation), we monitored changes in stereotypy performance in young Orange-winged Amazon parrots reared either in barren cages or cages provided with enrichments designed to facilitate foraging and locomotion. Unenriched parrots developed significantly more stereotypy than enriched parrots, and the mean time to stereotypy onset and the rate and magnitude of stereotypy increase also differed between the two groups. We then provided enrichment to the birds that had been reared in the barren cages. Following a 4-week delay, stereotypy was significantly reduced. These results show that stereotypy can be both prevented and reversed with appropriate environmental modification and illustrate how studying this behavior at many points over time can provide insights into its ontogeny.

The performance of silty soils in Emilia Romagna, Italy, during the 2012 earthquake offers an interesting opportunity for understanding their response under cyclic loading and susceptibility to liquefaction. A comprehensive investigation based on both in situ tests and laboratory tests (undrained cyclic simple shear tests) was performed for evaluating the cyclic strength of these low plasticity silty soils and thus analyzing data in light of the screening criteria for liquefaction triggering susceptibility. The laboratory results indicate that the soils are susceptible to liquefaction, whereas some types of interpretation approaches based on in situ tests appear to overestimate the liquefaction resistance of soils when applied to sands containing non plastic or low plasticity fines, thus suggesting a revision of the existing methods of analysis.