Immobility Response Research Articles

Reduction of the domestic chick's fear of human beings by regular handling and related treatments

Abstract. Fear of human beings can seriously jeopardize a chicken's welfare and performance and its reduction is therefore an important objective. The present study assessed the effects of various forms of regular human contact on subsequent avoidance of the experimenter and tonic immobility fear reactions in pair-housed, female domestic chicks, Gallus gallus domesticus. The results not only confirmed that regular gentle handling (picking up and stroking) is a potent and reliable method of reducing fear and avoidance of humans, but also illustrated the malleability of the handling process. Thus, avoidance of the experimenter was considerably reduced by each of the following treatments: (1) placing one's hand into the chicks' cage twice daily, with no attempt to initiate physical contact; (2) application of a rough-handling (suspension by the legs) regime: (3) letting chicks regularly observe their neighbours being picked up and handled; and (4) allowing visual contact with a human being who simply stood in front of and touched the wire-mesh wall of the chicks' home cage twice a day. The chicks' tonic immobility responses were also significantly shortened by treatments 1 and 3. Possible mechanisms underpinning the handling phenomenon are discussed. Although regular gentle handling of every bird is clearly not feasible in modern farming practice, the positive effects of the other experimental treatments suggest that the reduction of fear by regular human contact is extremely plastic. It is therefore considered likely to have practical application.

Projections from the periaqueductal gray (PAG) to the periambigual area: Relation to cholinergic vago-cardiac neurons

Activation of the midbrain periaqueductal gray (PAG) elicits species specific defense reactions and marked autonomic adjustments. In agreement with recent studies by Bandler and colleagues in the cat, we found that activation of rostrocaudally-oriented, longitudinally organized columns in PAG elicit differential cardiovascular and behavioral responses. Activation of dorsolateral/lateral PAG produces aggressive/flight behaviors accompanied by pressor responses while stimulation of ventrolateral PAG produces immobility and depressor responses. The pathways mediating these selective behavioral and autonomic responses are poorly understood.The projection from PAG to the sympathoexcitatory zone in the rostral ventrolateral medulla is a likely substrate for PAG-evoked pressor responses. However, circuits mediating PAG-evoked depressor responses are not known. The present studies have identified a robust, focal projection from PAG to the nucleus ambiguus (NA), a potent depressor area in the ventral medulla. In addition, we have used tract tracing techniques and immunocytochemistry to examine the organization of PAG projections in relation to cholinergic preganglionic parasympathetic NA neurons that innervate the heart.

Physiological correlates of the forced swim test in rats

Rats were tested in the forced swim test to evaluate the effects of duration of exposure (0, 5, 15, or 25 min), and water temperature (0, 35, 30, 25, or 20°C), on a variety of physiological measures. Serum corticosterone, glucose, lactate, phosphorus levels, and the anion gap (a measure of acid-base status) were increased significantly, whereas carbon dioxide and potassium levels were consistently decreased by testing, as was the potassium/phosphorus ratio; creatinine, triglycerides, and magnesium were not altered significantly in any study. Effects on prolactin, amylase, lipase, cholesterol, alkaline phosphatase, sodium, and chloride were inconsistent. Levels of serum corticosterone were increased at each duration of testing, and the increments were significantly higher than the previous duration. Corticosterone levels were also increased in proportion to decreasing water temperature, but the increments were not significantly different from the previous or following temperatures. Glucose levels were increased at every duration and at every water temperature with the exception of the coldest water temperature. Lactate and phosphorus levels and the anion gap were all increased, whereas carbon dioxide levels decreased after 5 min of immersion. Potassium levels did not decrease until some time after 5 min of testing. Immobility times were marginally correlated with corticosterone levels ( r = −0.38) but were highly correlated with serum carbon dioxide ( r = 0.59), potassium ( r = 0.67), and phosphorus levels ( r = −0.73); the correlation between immobility times and the ratio of potassium/phosphorus was 0.82. The potassium/phosphorus ratio accounted for 67% of the variance in immobility. These high correlations were interpreted in terms of acid-base changes associated with testing. The results shed new light on the physiological changes underlying the immobility response in the forced swim test. Although traditional stress measures such as corticosterone and glucose are reliable physiological stress measures, changes in serum potassium and phosphorus appear to reflect behavioral responses to water immersion stress more closely than these other measures.

Short-Latency Stressor Effects on Tonic Immobility Fear Reactions of Japanese Quail Divergently Selected for Adrenocortical Responsiveness to Immobilization

Despite evidence for a positive association between adrenocortical activation and fearfulness, the effects of chronic (12 to 20 h) exposure to stressful stimulation on the fear reactions of Japanese quail genetically selected for high (HS) or low (LS) plasma corticosterone response to immobilization stress are not straightforward. The present study examined tonic immobility fear responses in quail of both lines that, immediately prior to testing, either had been allowed to remain undisturbed or had been exposed to an acute stressor similar to that used in the selection program (i.e., a short-latency stressor; 5 min of immobilization). Tonic immobility responses were generally more pronounced in quail of the HS line than the LS line, and they were exaggerated in both lines after exposure to stress treatment. The findings provide further support for the suggestion that selection for exaggerated or reduced adrenocortical responsiveness may have been accompanied by a concomitant and unconscious effect on underlying fearfulness.

Differences in Fearfulness Indicated by Tonic Immobility Between Laying Hens in Aviaries and in Cages

AbstractThe aim of this study was to investigate whether there were differences in fearfulness between laying hens (Gallus gallus domesticus) housed in aviaries and in cages. The tonic immobility (TI) test was used to assess the fearfulness. Norwegian light hybrid White Leghorn hens were housed in battery cages and in three types of aviaries: the Marielund, the Laco-Volétage and the Tiered Wire Floor. Each system housed about 1,500 birds. Tests were performed on 50 birds per housing system at 70 weeks of age in one laying flock and at 30 and 70 weeks of age in the next.At 30 weeks of age in the second laying flock, the duration of the tonic immobility response was unaffected by type of system. At 70 weeks, however, hens in cages showed tonic immobility of longer duration than hens in aviaries, in the first as well as in the second laying flock No differences in TI between hens from the three types of aviaries were found. The duration of TI did not correlate with plumage condition or body-weight, except for a longer duration of TI with poorer plumage condition in aviaries at 30 weeks. These results indicate that the fearfulness of hens in cages, as measured by the TI test, increased considerably with time. The lower fearfulness shown by hens in aviaries suggests that this important aspect of welfare is more secured in aviaries than in cages.

The immobility response elicited by clamping, bandaging and grasping in the Mongolian gerbil ( Meriones unguiculatus)

When grasped by the skin of the nape and lifted into the air, the young of many altricial mammals exhibit an immobility response in which they tuck their limbs against their bodies and remain inert. Such a response can be induced in the adults of some species, especially if a stronger tactile stimulus such as bandaging the head and neck or clamping the skin of the nape, is applied. In this study, the immobility response of the Mongolian gerbil ( Meriones unguiculatus) is investigated, which appears to differ in potentially useful ways from other commonly studied species such as rats ( Rattus norvegicus). It has been previously reported that for rats clamping or bandaging had a more profound effect on the immobility response than grasping. Mongolian gerbils were tested will all three methods (grasping, bandaging and clamping), which were repeated at intertrial intervals ranging from 3 h to 40 days. Grasping induced a significantly longer duration of immobility than either bandaging or clamping. However, repeated trials significantly increased the duration of immobility induced by clamping, whereas repeated grasping or bandaging did not do so. The marked difference in the induction of the immobility response in gerbils as compared to rats, may provide a useful model for the study of this behavior.

Effects of test age, line and sex on tonic immobility responses and social reinstatement behaviour in Japanese quail Coturnix japonica

The tonic immobility (TI) response and social reinstatement (SR) behaviour (as assessed in a treadmill test) were measured in 1, 2, 4, 6 and 10 week old Japanese quail of lines selected for long (LTI) and short (STI) duration of TI weighted for independence from SR behaviour or high (HSR) and low (LSR) levels of SR behaviour weighted for independence from durations of TI. Irrespective of age, LTI line birds had the longest and STI line birds the shortest duration of TI. The duration of TI did not differ between the HSR and LSR lines. Levels of SR behaviour were always higher in HSR line birds than in birds of the LSR line. SR behaviour did differ significantly between the LTI and STI lines and was shown at levels intermediate between those of the HSR and LSR lines although pairwise comparisons of line differences were not necessarily significant. The age and sex of the birds did not influence the duration of TI but levels of SR behaviour were lower at 2 and 4 weeks than at other ages and males showed more SR behaviour than females.

Victim Reactions During Rape/Sexual Assault

Overt signs of victim resistance during rape are critical issues in the handling of and recovery from rape/sexual assault. However, a substantial number of victims do not resist the attacker in any way. Tonic immobility (TI), a well-known involuntary, reflexive response to fear-inducing stimuli, may aid in explaining the paralysis and “freezing” of many rape victims. In the present study, rape survivors were classified as immobile, intermediate, or mobile, based on a self-report measure. The immobile group manifested significantly more of the specific features associated with tonic immobility. Thirty-seven percent of the sample clearly demonstrated immobility during the attack. Various postrape behaviors and attitudes were found to be associated with the incidence of the immobility response.

Intrastriatal injections of dynorphin a fragments potentiate the dorsal immobility response in rats

The effects of bilateral intrastriatal injections (2.0 μg/side) of Dynorphin A 1–17 (Dyn A 1–17) and Dynorphin A 1–8 (Dyn A 1–8) and their related nonopioid fragments upon the dorsal immobility response (DIR) over a 1-h time course were investigated. Dyn A 1–17 and Dyn A 2–17 potentiated the duration of the DIR 5 min postinjection, whereas Dyn A 1–8 and Dyn A 2–8 potentiated the DIR duration at each time point over the hour with their greatest effect at 15 min. An SC injection of 4 mg/kg naloxone 15 min prior to central injections blocked the potentiation of the DIR effects of Dyn A.

Intracerebral haloperidol potentiates the dorsal immobility response in the rat

The effects of intracerebral microinjections of 4-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]-1-(4-fluorophenyl)-1-butanone (haloperidol) (1.0 μg, 0.5 μl) in five regions of the brain were tested on the duration of the dorsal immobility response (DIR) and the cling and bar catalepsy in the rat. The duration of the DIR was significantly potentiated (but not the cling and bar catalepsy) following 2-h postinjection of haloperidol in the caudate putamen, nucleus accumbens, and globus pallidus but not in the substantia nigra pars compacta or cortex. These data further expand the previous evidence of regional variations in dopamine to the effects upon inhibitory behaviors.

Maudsley reactive and nonreactive rats in the forced swim test: Comparison in fresh water and solied water

Maudsley reactive (MR) and nonreactive (MNRA) and Sprague-Dawley (SD) male rats were tested for their immobility response in the forced swim test when the water was fresh or soiled by a rat of the same or other strain. For all strains, rats tested in soiled water were less immobile than rats in fresh water. The three strains did not differ as producers of soiling substance, but did differ in their response to it. The MR strain was least responsive, whereas the MNRA and SD did not differ from one another. These results support a previous study suggesting that MR rats are more immobile than MNRA rats in the forced swim test. The interpretation of these findings regarding the use of the Maudsley rat strains as an animal model for studying anxiety and/or depression is discussed.

Effects of anxiolytic and antidepressant drugs on long-lasting behavioural deficits resulting from one short stress experience in male rats.

Exposure of male Wistar rats to one single session of ten inescapable footshocks induces changes in the behavioural responses to environmental stimuli as measured in the "noise test" 14 days later. Shocked (S) rats showed decreased locomotion and rearing during the first 3 min of exposure to a novel environment compared to control (C) rats. When the 85 dB background noise was switched off a marked immobility response emerged in S rats, concomitant with a further decrease in locomotion and rearing. In response to noise off, C rats showed hardly any immobility and a much smaller reduction in locomotion and rearing compared to S rats. These long-lasting changes in behaviour were not reversed by acute treatment with the antidepressants fluvoxamine (3.0-30.0 mg/kg) and desmethylimipramine (DMI, 2.5-10.0 mg/kg) injected IP 30 min before the noise test on day 14 following the shock session. Chronic treatment (day 1 to day 14) with fluvoxamine or DMI did not reverse the behavioural deficits induced by shock exposure. Diazepam (0.6-5.0 mg/kg) administered acutely only reversed the effects of shock on locomotion during the first 3 min of the noise test. Chronic treatment with diazepam normalized the shock-induced decrease in locomotion and attenuated the rearing decrease during the first 3 min of the test, and partially restored shock-induced changes in behavioural response to switching off the noise. The most potent drug in this study was the 5-HT1A receptor agonist flesinoxan (0.3-3.0 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Vasopressin prolongs behavioral and cardiac responses to mild stress in young but not in aged rats

In young male Wistar rats sudden silence superimposed on low intensity background noise evokes a relative decrease in heart rate. This bradycardia is accompanied by immobility behavior. In the present study, involving young (3 month), late-adult (14 month), aged (20 month), and senescent (25 month) rats the magnitude of the stress-induced bradycardia shows an age-related reduction while the behavioral immobility response remained unchanged during the process of aging. Arginine-8-vasopressin (AVP, 6 μg/kg SC) administered 60 min prior to the experiment led to a prolonged behavioral and cardiac stress response in young and late-adult rats, but not in aged and senescent animals. The peripheral and central mechanisms possibly involved in the failure of systemically applied AVP to improve bradycardiac stress responses in aged rats are discussed.

Vasopressinergic modulation of stress responses in the central amygdala of the Roman high-avoidance and low-avoidance rat

The central nucleus of the amygdala (CEA) is selectively involved in the passive component of the behavioral (immobility) and the accompanying parasympathetic response during conditioned, stressful environmental challenges. Vasopressinergic mechanisms in the brain seem to play a role in these stress responses. The effects of the neuropeptides arginine-8-vasopressin (AVP) and oxytocin (OXT) on modulating CEA activity during conditioned stress of inescapable footshock were studied in male Roman high-avoidance (RHA/Verh) and low-avoidance (RLA/Verh) rats, psychogenetically selected on the basis of shuttle-box acquisition behavior. In RLA/Verh rats, the cardiac and behavioral responses to the conditioned emotional stressor were bradycardia and immobility, suggesting an important role for the CEA in these rats. The RHA/Verh rats, however, failed to show any change in heart rate or immobility in response to a conditioned stress situation. The low dose of AVP (20 pg) in the CEA of conscious RLA/Verh has caused an enhancement of the stress-induced bradycardiac and immobility response. However, the high dose of AVP (2 ng) and OXT (200 pg) attenuated the bradycardiac and immobility responses in the RLA/Verh rats. Infusion of AVP and OXT in the RHA/Verh rats failed to induce any change in heart rate or immobility. Binding studies revealed that the AVP receptor selectively binds AVP with high affinity. In contrast, the OXT receptor recognizes both AVP and OXT with a similar (but lower) affinity. This suggests that the behavioral and autonomic responses of the high dose of AVP may be caused by OXT receptor stimulation. In conclusion, on the basis of the present results one may hypothesize that CEA differences in AVP and OXT innervation and/or receptor densities may contribute to the differences in coping strategy found in these animals.

Characterization of stress-induced long-term behavioural changes in rats: Evidence in favor of anxiety

Recently, we reported that rats exposed to one brief session of inescapable footshocks showed a gradually developing and long-lasting decrease in behavioural activity and an increase in defecation in an open field. The aim of the present study was to further characterize the long-lasting changes in behavioural responsiveness to environmental stimuli. For this purpose, behavioural paradigms validated as tools in the preclinical study of the psychobiology of depression were used. Footshocked rats (S) showed a decreased response latency in an one-way avoidance-escape task and decreased immobility in a forced swim test as compared to nonshocked control rats (C) 14 days after shock exposure. These S rats showed decreased behavioural activity and increased defecation as compared to the C rats in an open field test carried out 28 days after footshock exposure. In addition, footshock exposure did not affect the preference for or consumption of a 0.05% saccharin solution on a long-term basis, although a decreased consumption of this solution was evident in S rats on day 1 postshock. These S rats showed an exaggerated immobility response to a sudden reduction in background noise level compared to C rats while placed in a novel environment on day 11 postshock. We conclude that the long-term effects of one short session of inescapable footshocks are not compatible with what is supposed to represent behavioural manifestations of depression in animals. It is argued that the common denominator of shock-induced long-lasting changes is increased behavioural defensiveness, which is more likely related to increased fear and/or anxiety.

Differential effects of intrastriatal estradiol on the dorsal immobility response in male rats.

The effects of implants of 17 beta-estradiol and cholesterol in four regions of the dorsal striatum were tested on the duration of the dorsal immobility response in gonadectomized male rats. The dorsal immobility response was significantly potentiated by 4-h implants of 17 beta-estradiol in the dorsomedial and dorsolateral regions of the dorsal striatum but not in the ventromedial and ventrolateral regions. These data further support the growing evidence that estradiol acts directly but differentially on the striatum to affect behaviors in the rat.

Potentiation of the dorsal immobility response following intrastriatal injections of enkephalins

The effects of bilateral intrastriatal injections (1.0 μg/side) of leucine5- and methionine5-enkephalins and their related nonopiate fragments upon three measures of immobility over a time course were investigated. Both leucine5-enkephalin and des-Tyr1-leucine-enkephalin potentiated the duration of the dorsal immobility response (DIR) 15 min postinjection and over a 1-h time course. On the other hand, methionine5-enkephalin and des-Tyr1-methionine-enkephalin potentiated the duration of the DIR at 5 and 15 min. These enkephalins and their fragments had no effect upon vertical cling and bar catalepsy. In a second study, an SC injection of 4 mg/kg naloxone 15 min prior to the central injections blocked the potentiation of the DIR effects of the enkephalins.

The hyperactive spontaneously hypertensive rat learns to sit still, but not to stop bursts of responses with short interresponse times.

The spontaneously hypertensive rat (SHR) is hyperactive and has been proposed as an animal model of attention-deficit hyperactivity disorder (ADHD). Although ADHD in most cases is treated with central stimulants, behavior therapy has also been used, but with relatively limited success. The purpose of the present study was to investigate suppression of SHR hyperactivity by differentially reinforcing immobility (DRI) using a positive reinforcer. The DRI schedule required that the rat remain immobile in a particular part of an operant chamber, the target, in order to obtain the reinforcer. The time requirement, the DRI value, of these periods was increased progressively. The results showed that time spent on the target increased by increasing DRI value in both hyperactive and control rats. However, the total number of movements, on as well as outside the target, was higher for the hyperactive rats. The behavior grouped into two independent response components. One component consisted of immobility responses with durations less than 1 s, actually bursts of active responses; the other component consisted of immobility responses with durations more or less matching the DRI requirement. The reinforcement schedule modified the long-lasting immobility component in both groups. SHR received more reinforcers than WKY as long as the schedule did not require too long periods of immobility. However, the total number of movements on target was not reduced in SHR; on the contrary, it increased somewhat as the schedule requirements increased. If the behavior of ADHD children consists of two, or more, independent components similar to the ones observed in the present study, the present results may offer an explanation of why behavior therapy has limited success in the treatment of ADHD.

Opposite effects of central amygdaloid vasopressin and oxytocin on the regulation of conditioned stress responses in male rats.

The central nucleus of the amygdala (CEA) seems to be selectively involved in the passive component of the behavioral (immobility) and the accompanying parasympathetic response (bradycardia) during conditioned environmental challenges,' leaving conditioned sympathetic, adreno-medullary, and adreno-cortical responses unaffected (Roozendaal et al., in preparation). Robust monosynaptic, .peptidergic connections to the vagal complex and periaqueductal gray may be mediating these effects. Intracerebroventricularly administered arginine-8-vasopressin (AVP) potentiates these stress-induced bradycardiac and immobility responses.* AVP may exert these effects via AVP and/or oxytocin (OT) receptive systems in the CEA.' Microinfusion of AVP (dissolved in 1 p1 artificial CSF) into the CEA of conscious male Wistar rats under resting conditions, leads to a dose-dependent change in heart rate and behavior: A high dose of AVP (2 ng), but not lower ones (20 and 200 pg), causes a transient increase in heart rate and behavioral a~t iv i ty .~ Moreover, in a part of the animals, the low dose of AVP even causes an opposite effect, that is, bradycardia. OT administration (2 ng) induces responses similar to those induced with the high dose of AVP. Neither plasma norepinephrine nor epinephrine is influenced after AVP infusion, suggesting that the tachycardia is due to reduced parasympathetic control, rather than a stimulation of the sympathetic outflow. The effects of AVP and OT during conditioned stress were studied in male Roman high-avoidance (RHA) and Roman low-avoidance. (RLA) rats, selected genetically for shuttle-box acquisition behavior. In RLA rats the cardiac and behavioral responses to the emotional stressor are bradycardia and immobility,

Differential effects of dopamine D 2 agonist quinpirole upon the dorsal immobility response in rats

The effects of various dose levels of systemically injected quinpirole upon the dorsal immobility response (DIR) over a time course was investigated in male rats. A low dose of quinpirole (0.01 mg/kg) significantly attenuated the duration of the DIR following the 10-min interval, whereas the highest dose (1.0 mg/kg) had a biphasic effect so that at the 10-min interval the duration of the DIR was significantly potentiated and at the 60-min interval the duration of the DIR was significantly attenuated. The intermediate dose (0.1 mg/kg) had intermediate behavioral effects. The data support the growing evidence that quinpirole has differential effects upon behavior over time as a function of the dose levels. The present data were discussed in reference to presynaptic and postsynaptic dopamine D 2 receptor theory.