Forms Of Stereotypy Research Articles

Factors influencing stereotypic behaviours of animals rescued from Asian animal markets: A slow loris case study

Illegal wildlife trade has devastating effects on wild populations in Southeast Asia, made evident from the rising numbers of threatened species found in rescue centres. The prevalence of slow lorises (Nycticebus spp.) in trade allows for the first time, a study of the response of wild-caught strepsirrhines to a captive environment following a period of non-existent welfare. Many animals confiscated from trade arrive at rescue centres with mental and physical defects and regularly perform stereotypic behaviours. Our study assessed the prevalence of stereotypic behaviour in three species of Indonesian slow lorises (n=90) at a Ciapus Primate Centre in Java, Indonesia. We surveyed all slow lorises present, three times a night, every night, over a four-week period and recorded every time a slow loris exhibited stereotypies. We described the stereotypic behaviours witnessed and attempted to predict the occurrence of this behaviour. 33% of animals observed exhibited at least one of three forms of stereotypy – pacing, rocking head, circling. We examined extrinsic and intrinsic factors including sex, species, length of time in captivity, cage size and group composition to highlight stereotypic predictors. A logistic regression analysis revealed that 21.9% of variability in the presence of stereotypies could be explained by sex composition and number of conspecifics sharing an enclosure. Through experimenting with different size and sex composition of groups and distance to neighbouring groups, occurrence of stereotypies may be reduced. Numerous other factors not tested for, including a genetic predisposition to coping with life in captivity, could be responsible for these behaviours. As stereotypies in zoo-living lorises are rare, the brutal conditions of the trade may also play a major role in their prevalence in this study.

Reappraisal of spontaneous stereotypy in the deer mouse as an animal model of obsessive-compulsive disorder (OCD): Response to escitalopram treatment and basal serotonin transporter (SERT) density

Obsessive-compulsive disorder (OCD) is characterized by recurrent thoughts and repetitive motor actions. Hyposerotonergic signalling in the cortico-striatal circuitry is believed to be central to the pathology of OCD, while many patients only respond to chronic treatment with high dose selective serotonin (5HT) reuptake inhibitors (SSRIs). Confined deer mice spontaneously develop two forms of stereotypy, namely vertical jumping and pattern running. The purpose of this investigation was to reappraise these behaviours and strengthen the validity of deer mouse stereotypy as an animal model of OCD within a framework of three study questions: (1) can the time spent executing stereotypical behaviours be employed as a measure of extent of stereotypy, (2) does deer mouse stereotypy only respond to chronic, but not sub-chronic treatment with a high-dose SSRI, and (3) is deer mouse stereotypy associated with altered cortico-striatal 5HT transporter (SERT) binding? The current study demonstrates that treatment naïve high stereotypical (HS) deer mice spend significantly more time executing stereotypical behaviours while significantly less time is spent indulging in stereotypy following chronic, but not sub-chronic, treatment with escitalopram. Furthermore, HS deer mice present with a significant decrease in striatal SERT density compared to non-stereotypical (NS) controls. Building on previous validation studies, we conclude that deer mouse stereotypy is a valid naturalistic animal model of OCD with robust face, construct and predictive validity.

Some effects of audio and visual stimulation on multiple forms of stereotypy

Three experiments were conducted to evaluate the effects of audio and visual stimulation, alone or in combination, on the behavior of three children who displayed multiple forms of stereotypy (e.g., hand mouthing, body rocking). The results of experiment 1 showed that all three participants displayed different forms of stereotypy when audio and visual stimulation were provided versus when no stimulation was provided. The results of experiments 2 and 3 showed that the form of one participant's stereotypy, but not the other two, changed when visual stimulation and audio stimulation were presented separately. Overall, the results suggest that ambient stimulation may influence both the form of and time allocation to stereotypy. Copyright © 2005 John Wiley & Sons, Ltd.

Stereotypy I: A review of behavioral assessment and treatment

In this paper, we review definitional issues related to stereotypy, behavioral interpretations of stereotypy, procedures for determining operant function(s) of stereotypy, and behavioral interventions for stereotypy. In general, a preponderance of the assessment literature suggests that most forms of stereotypy are maintained by automatic reinforcement. Review of the treatment literature suggests that antecedent (e.g., environmental enrichment) and consequent (e.g., differential reinforcement of alternative behavior) interventions produce at least short-term reductions in stereotypy. Suggestions for further assessment and treatment of stereotypy are provided.

Physical condition at weaning affects exploratory behaviour and stereotypy development in laboratory mice

Laboratory mice of the ICR strain develop two morphologically distinct forms of stereotypy in the post-weaning period when kept under standard housing conditions. Wire-gnawing develops from single bites at the cage-lid during exploratory climbing whereas jumping originates from exploratory rearing at the cage wall. In a recent study nude mutants of ICR that were physically retarded around the age of stereotypy development performed more rearing but less climbing just after weaning and subsequently developed more jumping but less wire-gnawing than ICR mice (Würbel, H., Stauffacher, M. and von Holst, D. 1996. Ethology 102: 371–385). The two source behaviour patterns, climbing and rearing, could represent alternative strategies serving the same goal (e.g. exploration of external stimuli, escape). Since the ability to climb may depend on physical strength, preference for either of these two patterns may be determined by physical condition to some extent. As a consequence, the prefered pattern may determine the later form of stereotypy. To test these two hypotheses, 48 male ICR mice were assigned to three groups of 16 each. One group was prematurely weaned at day 17 to mimic physical retardation, the others were weaned at the standard weaning age of 20 days and divided into two groups of high and low weaning weight. Premature weaning was associated with a shift in the relative proportions of climbing and rearing towards rearing. Although heavy males showed most climbing and least rearing, weaning weight did not significantly affect performance of these two patterns. Subsequently, all mice developed stereotypic wire-gnawing but none of them showed stereotypic jumping. Although weaning age affected the performance of the two source behaviour patterns in the predicted way, the differences may not have been large enough to cause different forms of stereotypy. However, both, premature weaning and low weaning weight resulted in higher stereotypy performance when adult.

Relationship between amphetamine and environmentally induced stereotypies in pigs

The study investigated the relationship between the behavioural response to a standard dose of amphetamine and environmentally induced stereotypies in pigs. There were large individual differences in the frequency of amphetamine-induced stereotypies and time spent in locomotion. In addition, these tho measures tended to be negatively correlated each other, indicating that they were competitive. Levels of amphetamine stereotypies were negatively correlated with those of chain manipulation and drinking after a period of 50 and 100 days of physical restraint and food restriction; levels of locomotion were positively correlated with levels of chain manipulation after 100 days of restraint and restrictive feeding. These results suggest that pigs differ in their predisposition to develop environmentally induced stereotypies, and that this is related to catecholaminergic systems in the brain. In an amphetamine test performed after the period of restraint and restrictive feeding, amphetamine stereotypies were generally higher than in the first test but behaviour was no longer correlated to previous levels of environmentally induced stereotypies. The qualitative differences between the two forms of stereotypy, their negative rather than positive correlation, and the lack of correlation between environment-dependent stereotypies in the second amphetamine test suggests a complex relationship between these two forms of stereotypies. The increased amphetamine sensitivity in the second amphetamine test may reflect the effect of stress on central catecholaminergic systems.

Food deprivation reveals strain differences in opiate intake of Sprague-Dawley and Wistar rats

Two groups of naive, male, albino rats derived from different genetic strains (Sprague-Dawley and Wistar) were given a 5 μg/ml etonitazene solutions as their only available liquid. Liquid intake and body weights were recorded every 24 hr. Etonitazene intake was compared to baseline water intake, and drug intake was then compared when the rats were food deprived (25 sessions) and food satiated (24 sessions). Both groups drank similar amounts of water and etonitazene during the initial food satiation phase, although drug intake was slightly below water intake. When they were food deprived, the Wistar group's mean etonitazene intake almost doubled, while the Sprague-Dawley group's drug intake decreased by nearly 50%. The etonitazene intake in the Sprague-Dawley group never exceeded that of the vehicle, water; thus, it appeared that the drug was not functioning as a reinforcer. Food deprivation increased etonitazene intake above water levels in the Wistar group, indicating that the drug was serving as a reinforcer. Both groups showed similar drug effects during food deprivation, such as erratic drinking patterns, self-mutilation and other forms of stereotypy. Thus, both strains were sensitive to etonitazene's effects; they appeared to differ only with respect to the reinforcing effects. These results suggest that genetically-based differences in the reinforcing effects of drugs may be revealed by food deprivation.

The effects of adding interruption to differential reinforcement on targeted and novel self-stimulatory behaviors

This study compared differential reinforcement of other (DRO) and incompatible (DRI) behaviors to these same two procedures combined with a mild interruption procedure on a 6-year-old developmentally disabled girl's self-stimulatory behaviors. The results showed that the combination was more effective for reducing all of the targeted behaviors. These low rates were maintained at a 4-month follow-up. In addition, several new forms of stereotypy that appeared as the targeted behaviors diminished decreased rapidly when interruption was applied to them. Finally, independent toy play increased as a by-product of the treatment.

Replacement—A theory of stereotypy: A review

Three forms of stereotypy are described and an outline given of previous theories of simple stereotypy in the retarded and autistic. An alternative theory is put forward in which stereotypy is characterized as a replacement of unpalleatable stimuli and/or responses that are overloading the system in a way with which the individual cannot cope. Although the theory derives from cognitive psychology, it can also be expressed behaviorally or experientially without loss of impact. The manner in which replacement theory applies to the three types of stereotypy is described. Testable hypotheses are derived, predictions made, and implications considered. Finally, the more general ramifications of the theory are explored.

Effects of food deprivation on etonitazene consumption in rats

One group of free-feeding rats was given a 5 μg/ml etonitazene HCl solution as their sole liquid. This group increased their drug take by 100% when they were partially food-deprived during a 23-day period. Another group that remained food-satiated and received etonitazene for an equal number of days did not show similar increases in drug intake. However, this group drank greater volumes of the etonitazene solution than a food-satiated control group drank of water. These results are constrasted with a fourth group showing a 50% decrement in water intake during similar food-deprived conditions. The food-deprived group drinking etonitazene showed highly erratic drinking patterns compared to all the other groups. Daily liquid intake ranged from 30 to 250 ml in this group, and volumes oscillated from high to low on alternating days. When the food-deprived/food-satiated conditions were replicated in this experimental group, corresponding increases and decreases in drinking reliably occured. However, during the second food-deprived phase, the large increases occured almost immediately as contrasted with a gradual increase over 17 days during the first food-deprived phase. This would suggest a learning mechanism may be involved. Self-mutilation and other forms of stereotypy were noted only in food-deprived rats consuming etonitazene.