Avoidance Responding Research Articles

Potency and duration of action of the ACTH 4–9 analog (ORG 2766) as compared to ACTH 4–10 and [D-Phe 7] ACTH 4–10 on active and passive avoidance behavior of rats

Experiments were performed to examine the potency and duration of action of various ACTH analogs on active and passive avoidance behavior of rats. ACTH 4–10 and the ACTH 4–9 analog (ORG 2766) delayed extinction of pole-jumping avoidance behavior and facilitated passive avoidance responding. [D-Phe 7] ACTH 4–10 facilitated extinction of pole-jumping avoidance behavior and facilitated passive avoidance responding. ORG 2766 was a thousand times more active than ACTH 4–10. The effect of ORG 2766 on extinction of pole-jumping avoidance behavior and on passive avoidance behavior was of longer duration than that of ACTH 4–10. As determined more precisely in the passive avoidance test it appeared that the action of ACTH 4–10 lasted 3 to 6 hours, while that of ORG 2766 amounted to at least 24 hours. Although [D-Phe 7] ACTH 4–10 was a thousand times less active than ORG 2766 in the passive avoidance paradigm, its duration of action was of the same magnitude. In view of this, the marked increase in potency of the ACTH 4–9 analog cannot be explained only on the basis of its metabolic stability but also by an increased intrinsic activity.

Analysis of behavioural responses to an ACTH analog in CXB/By recombinant inbred mice

Male mice of the C57BL/6By and BALB/cBy inbred strains, their reciprocal F 1 hybrids, and 7 recombinant inbred strains, were tested for open-field activity, a shock-motivated successive reversal position discrimination problem in a T-maze, and a toggle box exploration task. The test battery was repeated one month later. Finally, mice were tested for the acquisition and extinction of a taste aversion conditioned by ethanol injection. Mice of each strain were tested after injection with saline or one of 3 doses of an ACTH analogue. Highly significant genotypic differences were found for all measures, an expected result. The strain distribution pattern seen in the toggle box suggested single gene mediation of exploratory activity after habituation. One aspect of avoidance responding and extinction of conditioned taste aversion also yielded strain distribution pattern consistent with single gene control. Peptide treatment reduced internal field crossings in the open field. This effect was not strain dependent. Peptide treatment had no effect on T-maze learning, conditioned taste aversion, or toggle-box exploration.

Ontogenetic differences in response to d-amphetamine: two-way avoidance, intertrial responses, and locomotor activity.

In Experiment 1, 15-, 17-, 21-, 36-, and 90-day-old rats were injected with either physiological saline, 0.5-, 1.0-, 4.0-, 8.0-, or 16.0-mg/kg of d-amphetamine sulfate and 20-min later they were allowed to explore a two-way avoidance apparatus for 8 min. Immediately following adaptation, they were given a single session of 100 two-way avoidance trials. In general, in all ages, there was a dose related increase in avoidance on the first block of trials. However, across trials avoidance of the two youngest ages decreased, avoidance responding by 21-day-old animals remained relatively constant, and avoidance of the oldest ages increased. In the three youngest ages, avoidance and intertrial responses had a similar pattern, but in older ages there was little relationship between avoidance and intertrial responses. Shuttle crossings during adaptation were increased more by higher doses in younger rats than adults. In Experiment 2, para-hydroxyamphetamine (1.0, 4.0, 16.0 mg/kg) did not alter two-way avoidance, intertrial responses, or crossings during adaptation in 15-, 17-, 21-, 36-, or 90-day-old rats. The age-dependent behavioral effects of d-amphetamine may be due to maturation of central nervous system catecholaminergic neurons.

On inferring selective association: Methodological considerations

The theoretically appropriate means for demonstrating selective association are discussed and shown to be empirically necessary. Following the acquisition of an unsignaled instrumental avoidance baseline, dogs received either CS-contingent shocks (CS+) or random, independent CS/shock presentations. The CS was either a tone or a flashing light. When the CSs were subsequently presented during avoidance responding, only the tone-CS+ group showed absolute facilitation of response rate. However, both tone- and light-CS+ groups showed facilitation relative to their respective random controls due to the nonassociative inhibitory effects of the light. A bidirectionally sensitive dependent variable enabled the detection of this pattern of effects. Thus, a demonstration of selective association requires (1) appropriate controls for nonassociative effects and (2) selection of a dependent measure that is sensitive to both excitatory and inhibitory influences.

Influence of dorsal rhizotomy on a sustained avoidance response in rats

Sustained avoidance responding was studied in each hind limb of rats before and after unilateral dorsal rhizotomy (T13 through L6, left). The subjects were required to make a change in the resting posture of the unseen hind limb, and to maintain the change, to avoid shock to a sensate area of the trunk. Two dichotomous training variables were manipulated: the presence or absence of preoperative training and the order of training of the two hind limbs. Although the animals rapidly reached criterion with sensate limbs before and after surgery, acquisition with dorsal rhizotomized (DR) limbs failed to occur except when the order of postoperative training was sensate limb:DR limb. Even then, acquisition was significantly slower with DR than intact limbs, and the topography of the avoidance response differed in the two cases. It appeared that response-related changes in body parts immediately surrounding the DR limb were not critical for successful performance, and when there was failure of acquisition, the number of training sessions was not a relevant variable. It was concluded that tonic movements cannot be acquired in the absence of peripheral topographic feedback from the responding body part, unless information concerning the general response requirement is first provided to the rat via training with a sensate limb.

Effects of morphine and chlordiazepoxide on avoidance behaviour in two inbred strains of mice

Morphine and chlordiazepoxide were tested in the inbred strains of mice DBA/2J (DBA) and C57BL/6J (C57), subjected to three daily 50-tria1 avoidance sessions in the shuttle-box. The DBA strain reached higher avoidance levels in comparison to the C57 strain after the administration of saline. Morphine facilitated avoidance responding in the C57 strain but not in DBA mice. An improvement in avoidance behaviour was observed following the administration of chlordiazepoxide in both strains of mice. Some favourable effects were obtained in DBA mice by combining morphine with chlordiazepoxide, whereas no interaction between these drugs was found in the C57 strain.

Behavioral and biochemical studies of the scopolamine-induced reversal of neuroleptic activity.

Scopolamine reversed the reduction in avoidance responding caused by spiperone and antagonized the inhibitory effects of spiperone on the behavioral actions of d-amphetamine or apomorphine. Scopolamine-induced locomotor activity was greater in 6-hydroxydopamine (6-OHDA)-treated animals than in controls. This increase was prevented by administration of alpha-methyltyrosine, but not by inhibition of dopamine-beta-hydroxylase, indicating that this action of scopolamine was associated with presynaptic dopaminergic fibers. Therefore, the possibility that pre-synaptic dopaminergic function was the locus of the antagonism of spiperone by scopolamine was examined using drug interaction studies in 6-OHDA-treated rats. However, when 6-OHDA-treated rats were given alpha-methyltyrosine, scopolamine still reversed the spiperone blockade of apomorphine-induced locomotion. Although these data provided evidence for a post-synaptic action for this cholinergic blocking agent, scopolamine affected neither dopamine-stimulated adenylate cyclase activity nor 3H-spiperone binding in vitro. Furthermore, scopolamine did not alter the level of specific 3H-spiperone binding found in brain after in vivo administration. This suggests that the post-synaptic mechanism affected by scopolamine is different from the site affected by spiperone. Thus, it is concluded that scopolamine can affect both pre- or post-synaptic events associated with dopaminergic function and that both may contribute to the reversal of the actions of spiperone.

Acquisition and retention of control of instrumental behavior by a cue-signaling airblast: How specific are conditioned anticipations?

The conditioned state evoked by a CS that had been paired with an aversive airblast was assessed by superimposing the CS on baselines of instrumental responding. The first experiment used a shock avoidance baseline; CS-airblast pairings were administered on the baseline, with the shock avoidance schedule in effect. The CS that signaled airblast came, over trails, to accelerate shock avoidance responding. As further CS-airblast trials were administered, however, the acceleratory effect of the CS decreased, producing an inverted-U-shaped acquisition curve. A second experiment used off-baseline CS-airblast conditioning, and the CS was tested on both shock avoidance and water reinforcement baselines. After 20 CS-airblast pairings the CS accelerated shock avoidance and suppressed water-reinforced responding. After 10o pairings, however, the acceleratory effect on shock avoidance was much attenuated, although the suppressions of the water-reinforced behavior did not differ between 20- and 100-trial groups. Two further experiments examined retention, over a 45-day interval, of the attenuation of the CS's effects on shock avoidance. Over the retention interval, this attenuation disappeared. It was, however, reinstated by giving the animals “reminder” presentations of the airblast. These results are interpreted as representing systematic changes in the specificity of the conditioned state evoked by a Pavlovian CS.

Effects of repeated administration of d-amphetamine on Sidman avoidance responding in rats.

The effects of repeated administration of d-amphetamine (0.5 mg/kg SC) on Sidman avoidance responding in rats were investigated. The response (lever-pressing) enhancing effect of d-amphetamine increased progressively after repeated administration. The change in behavior was more marked in the animals exposed to the avoidance situation during the period of the drug effect than in those given the drug after termination of each avoidance session. The present results suggest that the enhancing effect of d-amphetamine as demonstrated on Sidman avoidance responding in rats is dependent on the drug experience of the experimental animals and on the experimental situation to which the animals are exposed during the period of the drug effect.

The role of conditioned stimulus termination in short-latency avoidance responding in cats

The behavioral effects of two procedures for bar-pressing avoidance training in cats were studied. In one procedure conditioned stimulus (CS) termination was response-contingent on both shock and non-shock trials; in the other the minimal duration of the CS was equal to the CS-US (unconditioned stimulus) interval. When avoidance responses did not terminate the CS short-latency avoidance responses were not acquired, the cats made more intertrial responses, and removal of the proreal and orbital gyri interfered more with avoidance responding than was observed in the other group. Abolition of shock application and introduction of a fixed duration of the CS resulted in extinction of the avoidance responses, which was more rapid in cats trained under the response contigent CS termination procedure. The data suggest that responses performed during the CS-US interval should be divided into two subclasses: short-latency responses which not only avoid pain but also avoid fear conditioned to the CS, and long-latency responses which avoid pain and escape from the fear state.

The disinhibitory effect of arousal on fear responses: An analogue with implications for the treatment of phobias

Abstract An animal analogue of the model of phobia formation suggested by Lovibond (1966) generates data which support the thesis that high arousal serves to disinhibit and in some cases to potentiate fear states in subjects. It was predicted that a procedure which increased arousal in an experimental situation, after extinction of passive avoidance responding, would disinhibit the recently inhibited fear in the situation. Thirty-four of 42 dogs showed increased latencies to eat. Generalizations from animal analogues need to be treated cautiously but there does seem to be reason to take into account the disinhibition hypothesis when planning treatment of phobias.

Counterconditioning, Hierarchy, and CS Exposure in Extinction of Human Avoidance Responding

Eight groups of subjects were trained to make a button-press avoidance response and were then given 15 treatment trials before being tested for extinction. Subjects in the Flooding group were exposed to the 2000-Hz tone (CS) for 20.0 sec. irrespective of their responding. In six other groups subjects were treated according to a 2 × 3 design. They were either exposed to the original CS (CS groups) or a hierarchy of tone stimuli leading to the CS (Graded CS groups). Subjects were asked either to imagine nothing (CS-only and Graded CS-only), imagine neutral events (CS-neutral and Graded CS-neutral), or imagine pleasant events (CS-pleasant and Graded CS-pleasant). A Yoked-flooding group in which CS durations were identical to the CS durations in the CS-pleasant group was also tested. Testing during extinction showed that avoidance responding was most resistant to extinction in the CS-only, Graded CS-only, and Neutral groups and least in the Flooding group. The Pleasant groups showed quicker extinction than the Neutral, CS-only, and Graded CS-only groups. The CS-pleasant group was quicker to extinguish than the Yoked-flooding group. Although flooding was the most effective procedure, the results showed that not all the effects of response competition, through imagination of pleasant experiences, could be explained through the CS-exposure hypothesis.

Role of intertrial interval following an escape or avoidance response in bar-press avoidance

In three experiments, rats learned bar-press avoidance as a function of the intertrial interval following an escape or an avoidance. The general hypothesis is that the length of these intervals affects bar-press avoidance differentially, depending on whether an avoidance follows an escape (avoidance/escape) or an avoidance (avoidance/avoidance) on the previous trial. Specifically, it is proposed that short escape ITIs will facilitate avoidance/escape and avoidance/avoidance, while avoidance ITIs will have no effect on avoidance responding. The results tend to support this hypothesis. The shorter the intertrial interval following an escape, the higher the probability of both measures: avoidance/escape and avoidance/avoidance. No effect of avoidance interval was found on avoidance/avoidance. Unpredictedly, however, it was found that in comparison to a very short intertrial interval following an avoidance (0.5 sec), relatively long intervals (5 and 45 sec) facilitate avoidance/escape. These results were interpreted as mainly reflecting nonassociative factors such as shock-produced activity.

REDUCTION OF SHOCK DURATION AS NEGATIVE REINFORCEMENT IN FREE‐OPERANT AVOIDANCE

Rats were trained on a free-operant procedure in which shock duration was controlled by responses within a limited range of interresponse times. Shocks of 1.6-mA intensity occurred randomly with average density of 10 shocks per minute. As long as interresponse times were 15 seconds or less, any shocks received were at the briefer of two durations (.3 second). Whenever interresponse times exceeded 15 seconds, any shocks received were at the longer duration (1.0 second). For six of eight animals, avoidance responding developed quickly and reached levels of better than 90%. Four yoked animals stopped responding within the first few sessions. Shock duration reduction without change in shock probability or intensity was sufficient for the acquisition and maintenance of avoidance responding.

The role of conditioned stimulus termination in short-latency avoidance responding in cats

The behavioral effects of two procedures for bar-pressing avoidance training in cats were studied. In one procedure conditioned stimulus (CS) termination was response-contingent on both shock and non-shock trials; in the other the minimal duration of the CS was equal to the CS-US (unconditioned stimulus) interval. When avoidance responses did not terminate the CS short-latency avoidance responses were not acquired, the cats made more intertrial responses, and removal of the proreal and orbital gyri interfered more with avoidance responding than was observed in the other group. Abolition of shock application and introduction of a fixed duration of the CS resulted in extinction of the avoidance responses, which was more rapid in cats trained under the response contigent CS termination procedure. The data suggest that responses performed during the CS-US interval should be divided into two subclasses: short-latency responses which not only avoid pain but also avoid fear conditioned to the CS, and long-latency responses which avoid pain and escape from the fear state.

Psychological studies of stress ulcer in the rat

The behavioral animal models of stress ulcer in the rat include immobilization, conflict, predictability, coping and avoidance responding. Research with these ulcer techniques is briefly reviewed. The activity-stress ulcer model is described and recent findings summarized. Physiological investigations of stress ulcer have produced considerable information regarding the proximal causes of ulcer disease. Behavioral scientists can make significant contributions to the study of stress ulcer by evaluating predisposing variables and by observing the relevant precipitating environmental events which lead to ulcer development.

Effects of pretreatment with 6-hydroxydopamine or noradrenergic receptor blockers on the clonidine-induced disruption of conditioned avoidance responding

The effects of clonidine assessed on conditioned avoidance responses (CAR) in control, 6-hydroxydopamine (6-OHDA)- and vehicle-treated rats, using a shuttle box device. Clonidine (100–400 μg/kg) produced a significant decrease of CAR in control and vehicle-treated animals. On the other hand, avoidance responding was onyl slightly inhibited in the 6-OHDA-lesioned rats. Pretreatment with the α-adrenergic blocking drugs yohimbine or phentolamine (1–8 mg/kg) prevented the CAR disrupting effects of clonidine. When animals were pretreated with the β-adrenergic blocking agent propanolol (1–8 mg/kg) the ensuing injection of clonidine caused a greater CAR depression. Our results further support the hypothesis relating the conditioned performance depression observed after clonidine to the activation of a presynaptic negative feedback mechanism mediated by α-adrenoceptors. It is also suggested that propanolol increases the clonidine inhibition through the blockade of a positive feedback mechanism dependent on the activation of presynaptic β-receptors.

Physostigmine: Effects on fear or defense responses in the rat

Previous research had shown that the anticholinergic drug, scopalamine, decreased innate defensive responses of rats to a live cat or mechanical robot, and that the effects of scopolamine were attributable to actions of the drug on the central nervous system. In the present research, the anticholinesterase, physostigmine, which increases central cholinergic activity, caused an increase in the defense responses of male hooded rats. Physostigmine caused significantly more freezing and significantly more suppression of feeding and suppression of time near the aversive stimulus (ROBOT). Dose-response curves showed a positive, linear relationship between dose (0.025, 0.05, 0.1 and 0.2 mg/kg) of physostigmine and defense responses. The present results could not be attributed to general response suppression since the effects of physostigmine were situation-specific, i.e., the drug had no significant effect on behavior in the non-aversive or NO ROBOT condition. The present results were taken as further evidence of the involvement of cholinergic activity in the mediation of defense responses. The effects of cholinergic and anticholinergic drugs on the observable defense response of freezing were thought to have important implications for the large literature relating these drugs and avoidance responding.

Aversive CS control of instrumental avoidance as a function of selected parameters and method of Pavlovian conditioning

Effects of aversive CSs upon dogs' instrumental avoidance responding were assessed as a function of the Pavlovian conditioning parameters using off-baseline (Experiment 1) and on-baseline (Experiment 2) conditioning procedures. In each experiment, three UCS intensitites (2, 6, and 10 mA) were crossed factorially with two CS-UCS intervals (10 and 90 sec) yielding six groups. After 4 days of conditioning, the CS-produced effects on avoidance were determined primarily by an interaction between Pavlovian procedure (off- versus on-baseline) and UCS intensity. With off-baseline conditioning, CS-produced facilitation of avoidance was an increasing function of the UCS intensity. However, with on-baseline conditioning, only the CS paired with weak UCS facilitated avoidance, and the CS paired with the strong UCS suppressed responding. This reversing parametric function poses problems for two-process motivational theories of avoidance.

Brain biochemical and behavioral changes in 4 weeks old rats after neonatal oxygen deprivation

The acquisition of a conditioned avoidance response (CAR) and the effects on monoamine neurotransmittor synthesis was investigated in 28 days old rats after neonatal oxygen deprivation (100% N 2 for 20 min or 6% O 2-94% N 2 for 4.5 hr). The rats subjected to 6% O 2-94% N 2 for 4.5 hr at 1 day of age were markedly inferior in the CAR acquisition than the control group. The animals subjected to 20 min neonatal anoxia did not differ in avoidance responding compared to controls. Tyrosine hydroxylase and tryptophan hydroxylase activity was studied in vivo in whole brain at 28 days of age by measuring the accumulation of dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) respectively after inhibition of aromatic L-amino acid decarboxylase with NSD 1015. An inhibition of tyrosine hydroxylase and tryptophan hydroxylase activity was found after neonatal exposure to 6% O 2-94% N 2 for 4.5 hr while the rats exposed to 100% N 2 for 20 min did not differ from controls. The precursor amino acids tyrosine and tryptophan and the levels of the endogenous monoamines dopamine (DA), noradrenaline (NA) and 5-hydroxytryptamine (5-HT) did not differ from controls in any of the groups. It is suggested that the observed behavioral deficits after prolonged hypoxia may be due to an impaired development of central catecholamine mechanisms.