Effect of looming object on immobility reaction in gallinaceous birds (Gallus gallus).

Immobilized White Rock chicks and presented them with 2 variations of a looming object (near vs far approach). The experimental group (n = 20), whose duration of immobility was reduced by a handling procedure, demonstrated significantly more adaptive responses (i.e., termination of the immobility reaction and avoidance) than a nonhandled control group (n = 18) for the near-approach condition. No significant differences between groups were found for either the far-approach condition or a control condition for spontaneous termination of the response. Results are considered in the context of reactions of infrahuman organisms to external stimulation under fear-arousing conditions. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medicine in the vocal arts

The effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on the central nervous system (CNS) were studied in rats. Behavioural and neurochemical studies were performed. Results show that acute and oral administration of dimethylamine 2,4-D was able to decrease locomotion and rearing frequencies and to increase immobility duration of rats observed in an open-field test. Treatment of rats with p-chlorophenylalanine (PCPA) was unable to change rat's open-field behaviour; 5-hydroxytryptophan (5-HTP) administration not only increased locomotion and rearing frequencies but also decreased immobility duration. Pretreatment of the rats with PCPA and 5-HTP decreased and increased dimethylamine 2,4-D effects, respectively. The herbicide was not able to change the striatal levels of dopamine and homovanilic acid but decreased the striatal levels of serotonin (5-HT), as observed for the doses of 100 and 200 mg/kg and increased those of 5-hydroxyindoleacetic acid (5-HIAA) as measured after the 200 mg/kg dose treatment. When the levels of serotonin and 5-HIAA were measured at the brain stem level, only those of 5-HIAA were modified, being increased by diethylamine 2,4-D (60; 100 and 200 mg/kg); this increment on 5-HIAA levels was observed even 1 hr after pesticide administration. Further analysis showed that 2,4-D concentrations chromatographically detected both in serum and brain of the intoxicated animals were dose-dependent, being found as early as 1 hr after the smaller dose of the herbicide used (10 mg/kg). The results suggest that diethylamine 2,4-D modify 5-HT functional activity within the CNS.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of inducible nitric oxide synthase in cardiac allograft rejection

Rats were exposed to either a footshock stimulus (FS) or emotional stimulus (ES, forced perception of another rat receiving footshocks) during a daily 10-min session for 5 consecutive days. The consequences of FS and ES on their behavioural responsiveness were assessed at different post-stress intervals using a small open-field. FS induced a decrease in ambulation, rearing and sniffing and an increased immobility in the small open field. These effects were present in rats tested immediately after the last session and remained present for at least 15 days. In contrast, ES induced a transient decrease in ambulation and rearing immediately after the last session, but in the period from half an hour until at least 15 days after the stimulus experience, an increase in ambulation, rearing and sniffing was observed. Exposure to one footshock per session for 5 consecutive days or to 10 footshocks in a single session also resulted in a long-lasting reduction in ambulation and sniffing and an increase in immobility. The former regime did not influence the behavioural response of ES rats, but the latter resulted in an increase in ambulation, rearing and sniffing in ES rats. Naloxone (1 mg/kg s.c.) pretreatment antagonized the increased behavioural activity of the ES rats whereas the activity of control and FS animals was not affected, suggesting an involvement of endogenous opioid systems in the behavioural responses observed in ES rats. It is suggested that the behavioural responses of the ES and FS animals are regulated by different mechanisms.     

Pinch-induced catalepsy in mice.

Pinch-induced catalepsy (PIC) was readily obtained in 5 strains of male mice (N?=?160) following repeated administration of strong pinches at the scruff of the neck. PIC outlasted the pinch by minutes and was more easily induced on retests 48 hrs after the initial acquisition test. Repetitive tail pinches and/or exposure to the testing procedure without pinches also resulted in immobility; however, this was mild and brief. Treatments to prevent immobility between trials (swimming in water or housing in the home cage with normally behaving littermates) failed to block or modify PIC. Spacing the trials up to 1 pinch/10 min did not affect the emergence of PIC, but at 1 pinch/30 min it was abolished. PIC is strikingly similar to the behavior elicited in mice when attacked by a cat. In both cases, immobility is produced by pinches or bites at the scruff of the neck, and it outlasts the duration of the stimulus. Results support the notions of PIC as an adaptive coping strategy, increasing the chance of survival in predator/prey confrontations. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of castration and testosterone in experimental models of depression in mice.

In the behavioral despair (forced swimming) test and in the tail-suspension test, long-term (30–32 days) castration significantly increased the duration of immobility in mice. Testosterone propionate (1 or 10 mg/kg/day–2 sc for 4 days), although not affecting the duration of immobility in sham-operated mice, reduced the duration of immobility in castrated mice to within normal limits. Desipramine (20 mg/kg ip) decreased the duration of immobility both in sham-operated and in castrated animals. These results indicate that castration favors an inactive behavior and that testosterone, although having no "antidepressant" effect per se, is necessary for the male animal to cope normally with adverse environmental situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Amphetamine-induced conditioned activity and sensitization: the role of habituation to the test context and the involvement of Pavlovian processes

Behaviours associated with drug action can sometimes be elicited, in the absence of drug, by exposure to stimuli that were present during drug administration. Such a finding is usually interpreted as a conditioned drug effect. Often, however, the outcome could arise if drug administration in a particular environment retarded behavioural habituation to that environment. To test the 'habituation hypothesis' of conditioned drug effects, mice received 10 daily injections of d-amphetamine ('paired' group) or saline ('unpaired') in test boxes, and the converse injections in the colony room. Another group received saline in both environments. The apparatus and procedures yielded minimal habituation of behaviours (ambulation and rearing) over sessions. Only the paired group demonstrated behavioural sensitization, indicating environment-specific sensitization. The paired group also showed more ambulation and rearing than the others on the critical test of conditioning (saline injection in test box); moreover, their conditioning test scores were higher than those of the other groups on their first exposure to the test boxes, contradicting the habituation hypothesis. Further supporting the involvement of Pavlovian conditioning, levels of ambulation and rearing measured for 10 min before each injection increased in the paired group, relative to the unpaired groups, over successive pairing sessions. Tests controlling for differential handling/injection experience produced results consistent with those previously obtained. Together, the findings are incompatible with the habituation hypothesis, and further support the role of Pavlovian conditioning.     

The effect of a single or repeated period of high stocking density on the behavior and response to stimuli in broiler chickens

Broiler chickens are normally housed at a fixed number per unit area throughout their life, which reduces their opportunity for movement during the later stages of rearing. An experiment is described that exposed broilers to a high stocking density either once or twice in the rearing period, and investigated the effects on the birds' behavior, and the response to other birds and humans after the second exposure to high or low stocking density. The stocking density was increased from a low level (1.7 kg/m2) to a high level (14 kg/m2) for the 2nd and/or 4th wk of rearing, or left unchanged at the low level. When stocked at the low rate, the birds spent more time walking and sitting and less time dozing and sleeping. They pecked more at inanimate objects and interacted more with other birds, but this did not include aggressive interaction. The effects of stocking density on behavior were greater in Week 4 than in Week 2, but there was no evidence that exposure to a high stocking density in Week 2 influenced the birds' behavioral response to a high stocking density in Week 4. Where stocking density did affect behavior in both Weeks 2 and 4, there was evidence of the response being cumulative. The activity of birds in the presence of another bird restrained in an open field arena was greatest when they had been stocked at the low density throughout the experiment. When a familiar person was in the arena, the birds that had been stocked at the high density in Week 2 were most active, but these birds showed the longest tonic immobility when inverted in a cradle. It is concluded that a high stocking density reduces activity in broiler chickens, and that birds stocked at a high density early in the rearing period are most active in the presence of people and show the longest tonic immobility in response to a fearful stimulus.     

Buspirone enhances immobility in the forced swim test in mice

We studied the effects of buspirone and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on duration of immobility in mice in the forced swim test. Buspirone [3-10 mg/kg, intraperitoneally (IP)] potently and dose dependently increased the duration of immobility in mice. In contrast, following a single dose of 8-OH-DPAT (1-3 mg/kg, IP), there was a dose-dependent decrease in the duration of immobility. Pretreatment with the 5-HT synthesis inhibitor p-chlorophenylalanine (200 mg/kg, IP, 3 days before further drug treatment) did not alter the effects of buspirone or 8-OH-DPAT. The increase in the duration of immobility induced by buspirone (3 mg/kg, IP) was blocked by NAN-190 [1-(2-methoxyphenyl)-4-(4-[2-phthalimido]butyl)-piperazine hydrobromide, 1 mg/kg, IP], a postsynaptic 5-HT1A receptor antagonist. However, the effect of 8-OH-DPAT (1 mg/kg, IP) was not blocked by NAN-190 (1 mg/kg, IP). The effect of buspirone (3 mg/kg, IP) was blocked by apomorphine (0.3 mg/kg, IP), a dopamine receptor agonist. Based on the results of this study, it is suggested that the effects of buspirone and of 8-OH-DPAT on immobility in the forced swim test may occur through different mechanisms.     

Aversiveness of the induction of tonic immobility in chickens (Gallus gallus).

Notes that, because of its sensitivity to various manipulations associated with either increases or decreases in aversive stimulation, tonic immobility seems to qualify as a fear reaction. The present experiments provided an independent assessment of the aversive properties of immobility induction. In Exp I, using 32 Production Red day-old chickens, a cue previously paired with onset of immobility suppressed activity in a stabilimeter. Similarly, in Exp II, with 24 Production Red day-old chickens, response-contingent immobilization produced punishmentlike effects in an instrumental conditioning paradigm. Taken together, results support the notion that the physical restraint involved in immobility induction is an aversive event. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alarm call responsivity of mallard ducklings (Anas platyrhynchos): IV. Effects of social experience.

In previous experiments on alarm call responsivity, mallard ducklings have been reared in a partially isolated condition in individual boxes that facilitate individual identification. The present study was designed to determine whether a more natural social rearing condition affects freezing behavior. In 3 experiments with mallard ducklings, rearing Ss socially in a 12-bird brood without a hen resulted in a significant reduction in alarm call responsivity. It is suggested that this reduction was caused by a decrease in the level of vocalizations uttered by socially reared Ss. Stimulating socially reared Ss with distress notes, contentment notes, or pre-exodus assembly calls reinstated high levels of freezing. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear and affiliation in domesticated male rats.

Male rats actively seek the opportunity to interact with other male rats. Three experiments with 208 Long-Evans males examined the hypothesis that the presence of conspecifics can reduce the behavioral signs of fear and that this capacity provides part of the attraction to conspecifics. In Exp I, the immobility response was measured following exposure to a stressful noise. Ss that were observed in groups exhibited shorter durations of immobility than those observed alone. The "group" effect was sufficiently powerful to nullify different housing conditions and different degrees of familiarity among the Ss. Exp II compared social and nonsocial stimuli and found that only the former effectively reduced the immobility response. In Exp III, stressed Ss were more likely to choose to interact with a conspecific in a T-maze than were nonstressed Ss. Again, rearing conditions made little difference; both individually and group housed Ss were highly attracted to a conspecific. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Internal inclusions in brown eggs: relationships with fearfulness and stress

Tonic immobility reaction and heterophil: lymphocyte ratio (indices of fearfulness and stress, respectively) were studied in hens laying eggs with or without internal inclusions (blood and meat spots). Two brown egg Spanish breed of chickens were used. There were no significant differences between groups in terms of tonic immobility duration. Birds of the group with internal inclusions appeared to be less fearful when defined by the number of inductions to achieve tonic immobility (1.4+/-0.1 vs 1.1+/-0.1; P < 0.01). Tonic immobility duration was significantly shorter in the group of hens with internal inclusions, when only those laying the abnormal egg the day before measurement of tonic immobility were included in this group (264+/-33 vs 395+/-30 s; P < 0.01). There was a significant difference in the heterophil:lymphocyte ratio between the two groups of hens (P < 0.01), mean value being significantly higher in the group with internal inclusions (0.43+/-0.02) than in the control group (0.33+/-0.02). Hens that laid eggs with internal inclusions had significant heterophilia (P < 0.01). Differences were consistent across the breeds. The incidence of internal inclusions was significantly greater (P < 0.001) in eggs with pink shells (an abnormality associated with the effect of stress). The results suggest that the laying of eggs with internal inclusions involves changes in fearfulness and stressfulness of hens.     

Tryptophan and tonic immobility in chickens: Effects of dietary and systemic manipulations.

Consistent with a serotonergic-midbrain raphe model of tonic immobility, 4 experiments designed to evoke changes in serum tryptophan produced reliable effects on the duration of the response in a total of 114 Production Red chickens. Systemic injections of tryptophan, the dietary precursor of serotonin, led to a dose-dependent increase in immobility, with optimal effects observed within 30 min after injection. Dietary depletion of endogenous tryptophan attenuated the duration of immobility, and a diet completely free of tryptophan, but supplemented with niacin, practically abolished the reaction. Dietary replacement of tryptophan reinstated the response. In a 5th experiment with 20 Ss, tryptamine, an alternative metabolic by-product of tryptophan, had no effect on immobility. Data are discussed in light of evidence showing serotonergic involvement in tonic immobility. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of administration of adrenalin on immobility reaction in domestic fowl.

Results of 2 experiments with White Leghorn chicks (N = 49) lend support to the hypothesis that tonic immobility is mediated by fear. In Exp. I, Ss injected subcutaneously with adrenalin remained immobile for a significantly greater duration than Ss injected subcutaneously with physiological saline. In Exp. II, it was found that a subcutaneous injection of adrenalin both facilitated the onset and maintained the duration of the immobility reaction in nonsusceptible Ss which previously showed no immobility. An injection of physiological saline neither facilitated nor maintained the immobility reaction in a control group of nonsusceptible Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tonic immobility in chickens: Possible involvement of monoamines.

In 4 experiments with a total of 259 Production Red chickens, it was found that tonic immobility was affected by a variety of drugs that act on monoaminergic systems. Compounds that enhanced the duration of tonic immobility were dextro-LSD, 2-bromo-dextro-lysergic acid (BOL-148), pargyline, and iproniazid; no effect was found when Ss were given 5-hydroxytryptophan, para-chlorophenylalanine, or atropine. Injections of serotonin depressed response duration. A suggestive parallel was noted between the results of the present study and those of previous work reporting drug-induced suppression of raphe electrical activity. The data implicate monoamines, especially serotonin, in the mediation of behavioral activation and suppression. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal ablation prolongs immobility response in rabbits (Oryctolagus cuniculus).

Hypothesized that damage to the hippocampus would reduce tonic immobility in rabbits. 2 measures were used with 14 implanted and 6 control Dutch Belt rabbits: the number of successful inductions of tonic immobility in a test session and the duration of each successful immobilization. Both of these measures increased in Ss with hippocampal lesions rather than decreased as expected. It is suggested that the hippocampus may act to suppress any ongoing dominant or prepotent response, whether the response involves movement or cessation of movement. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ability of rats to discriminate their own behaviours.

Studied the ability of 4 male black hooded rats to discriminate their own behavior in a 4-lever box. A buzzer indicated the availability of a reinforcement on 1 lever, and the correct choice was determined by the S's own behavior at buzzer onset. Face-washing, walking, rearing, and immobility were discriminated at a performance level well above chance. These discriminations were probably not based on environmental cues. The similarity of this "self-report" in rats to self-report in man is discussed. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholinergic modulation of tonic immobility in the rabbit (Oryctolagus cuniculus).

Conducted a study with 13 adult Dutch Belt rabbits to determine the effects of the anticholinergic agent scopolamine and the cholinergic agent physostigmine on tonic immobility in rabbits. Recordings of the EEG activity from cortex and hippocampus were also made before, during, and after each test session. Scopolamine significantly prolonged the response and produced large amplitude slow wave activity in the EEG of both cortex and hippocampus. Physostigmine significantly shortened the duration of immobility and increased rhythmic slow activity in the frequency range of 5.5-9.1 Hz in the hippocampus while producing a desynchronized cortical rhythm. It is suggested that the cortex and hippocampus play a role in modulating tonic immobility duration by inhibiting the brain-stem structures thought to control this response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopaminergic and cholinergic influences on motor behavior in chickens.

Examined the effects and interactions of apomorphine (AP; 0–4.0 mg/kg, ip), haloperidol (HAL; 0–2.0 mg/kg, ip), scopolamine (SCO; 0–2.0 mg/kg, ip), and pilocarpine (PIL; 0–50 mg/kg, ip) on stabilimeter activity and tonic immobility in White Leghorn?×?Black Australorp male chickens. The dopamine receptor agonist AP enhanced motor activity and decreased the duration of tonic immobility behavior in a dose-dependent manner. HAL, a dopamine receptor antagonist, increased the duration of tonic immobility and attenuated AP-induced increase in activity. Motor activity could also be increased by the cholinergic antagonist SCO. In addition SCO decreased the duration of tonic immobility. On the other hand, the cholinergic agonist PIL increased tonic immobility behavior and decreased SCO's effect on motor activity. Studies of the interaction of dopaminergic and cholinergic systems showed that HAL could attenuate the activity-stimulating effects of SCO, whereas PIL had a similar, but lesser, effect on AP-induced activity. Results support the suggestion that in birds, as in mammals, the dopaminergic and cholinergic systems are intimately involved in the expression of motor behavior. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tonic immobility in the blue crab (Callinectes sapidus, Rathbun): Its relation to threat of predation.

Investigated the tonic immobility response in the blue crab in a series of 7 experiments, using a total of 209 blue crabs. Although reported to be a powerful variable in other species, preinduction electric shock produced inconsistent increases in the duration of tonic immobility with the Ss. Manipulations that were more directly relevant to the fear of predation had considerably greater effects than shock. Physical damage to the chelipeds, mirror image stimulation, and immobilization beneath artificial glass eyes all produced significant prolongation of the immobility episode. Ss immobilized on a bed of sand rather than on a hard surface showed shorter immobility durations, suggesting that opportunity for escape is an important variable affecting the immobility reaction. Results support the contention that threat of predation is the organizing principle behind tonic immobility. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)