Extinction and retention of a classically conditioned flexor nerve response in acute spinal cat.

Conditioned adult male and female cats by pairing a mild electrical stimulus to the superficial peroneal sensory nerve (CS) with a stronger electrical stimulus to the ankle skin (UCS) of the same leg. Subsequent extinction was produced by presenting CS-alone trials. In Exp I (42 Ss), Ss given massed extinction trials showed response decrements to base levels, but Ss that received distributed extinction trials showed no decrements. In Exp II, .5-, 1-, 2-, 3-, or 4-hr intervals between acquisition and extinction produced no significant differences in the extinction data. In Exp III (20 Ss), Ss received extinction trials immediately or 30 min after acquisition trials, followed by 20 additional extinction trials 30 min later. Data indicated significant acquisition and extinction in the 10- and 20-acquisition trial groups. As in Exp II (35 Ss), varying the interval between acquisition and extinction did not produce any group differences in the extinction data. These results demonstrate that response increases produced by paired trials in the spinal preparation do not decay spontaneously over time and are not caused by sensitization effects. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response prevention and extinction of escape behavior: Duration, frequency, similarity, and retraining variables in rats.

Describes 3 experiments in which a total of 158 female hooded rats received escape training, response prevention, and then regular extinction. Following training, Ss in Exp I received 1 response-prevention trial lasting 0, 120, 240, or 400 sec, or multiple trials (6, 12, or 20) lasting 20 sec each. Extinction was faster as prevention duration or frequency increased. At each duration, extinction was faster following multiple- than following single-prevention trials. In Exp II Ss received "prevention" in the original escape situation or in similar or dissimilar situations. Extinction was faster as prevention and training situations increased in similarity. To evaluate the persistence of prevention effects, in Exp III Ss received shock retraining between prevention and regular extinction. Retraining attenuated but did not eradicate the effects of prevention. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vagotomy facilitates extinction of conditioned taste aversions in rats.

Results from 3 experiments indicate that severing the subdiaphragmatic vagus in male Sprague-Dawley rats increased the rate of extinction of learned taste aversions. In Exp I, when the illness-inducing agent was the blood-borne toxin apomorphine, vagotomized Ss tended to consume more saccharin than controls during repeated extinction tests. In Exp II, vagotomy disrupted retention and increased extinction of a preoperatively acquired saccharin aversion. Disruptions were found when the taste aversion was induced by copper sulfate, a local gastric irritant, or apomorphine. Exp III demonstrated that vagotomy did not affect retention or extinction of a shock-induced conditioned emotional response to noise. It is concluded that integrity of the vagus is not necessary for acquisition of a learned taste aversion when a blood-borne toxin is used as the illness-inducing agent. However, the vagus apparently mediates an integral portion of the CR following taste–illness acquisition. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned taste aversion in lean and obese rats with ventromedial hypothalamic knife cuts.

Assessed the development of a conditioned taste aversion (CTA) in 60 female Sprague-Dawley rats made hyperphagic with parasagittal knife cuts in the ventromedial hypothalamus (VMH). Ss were water deprived and presented with a .1% saccharin solution paired with injections of either LiCl or NaCl. In Exp I, VMH Ss tested at a nonobese weight level did not differ from sham-operated controls in acquisition and extinction of the CTA. In Exp II, moderately obese VMH Ss displayed a stronger CTA than did sham-operated controls as evidenced by slower extinction. A 2nd group of obese VMH Ss given an amount of LiCl equivalent to that given to the controls also displayed retarded extinction of the CTA. Results reflect an obesity-induced suppression in appetitive motivation. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A homeostatic model of Pavlovian conditioning: Tolerance to scopolamine-induced adipsia.

In Phase 1 of Exp I, with 60 male Sprague-Dawley rats, Ss given access to water while under the influence of scopolamine developed adipsic tolerance, but Ss denied access to water in the drug state did not. In Phase 2, Ss displayed adipsic tolerance only when scopolamine was administered with cues associated with previous drug injections. In Phase 3, adipsic-tolerant Ss showed a polydipsic response to an injection of phenobarbital relative to nontolerant Ss with the same pharmacological history. In Exp II, with 48 male Sprague-Dawley rats, the effect of deprivation level on the Pavlovian extinction of adipsic tolerance was assessed. Ss satiated with water during extinction showed a loss of adipsic tolerance, but water-deprived Ss did not. The proposed model is discussed in relation to (1) tolerance in other response systems such as morphine analgesia, (2) theories of extinction for nonpharmacological Pavlovian conditioning, and (3) homeostatic regulation and incentive motivation. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Problem-specific information and the development of problem-type schemata.

Examined the proposition that problem-type schemata include both problem-specific and abstract information. Recognition priming was used to capture schema acquisition as it evolves in analogical problem solving. Priming was used to show that Ss form associations in memory between problem-specific sentences drawn from analogous problems. In Exp 1, Ss formed such associations but only when analogical transfer was facilitated. In Exp 2, Ss formed associations only among sentences that related to abstract problem information. In Exp 3, Ss did not form associations among sentences that interfered with access to abstract information during transfer. In Exp 4, Ss accessed problem-specific sentences in problem-type schemata when given new problems of the same type. The results suggest that problem solvers retain problem-specific information in schemata because the information affords access to abstract information during transfer. Results are discussed in terms of a conservative generalization model of schema acquisition that emphasizes the importance of problem-specific information in problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors modulating the effects of teleost telencephalon ablation on retention, relearning, and extinction of instrumental avoidance behavior.

Examined the nature of avoidance behavior in a total of 65 goldfish (Carassius auratus) in 2 experiments. In Exp I, a master/yoked design was used to determine the degree to which Pavlovian conditioning would generate acquisition of a shuttle response by 24 Ss. Results indicate that the sequence of signal-shock pairings experienced by the avoidance Ss was not in this situation sufficient to explain the development of the instrumental avoidance responding. In Exp II, the effects of 3 variables on the retention and extinction of the avoidance response were studied. First, unilateral lesions of the telencephalon produced a transient deficit from which the Ss recovered to normal levels. Retention of avoidance response after bilateral telencephalon ablation was impaired and never fully recovered with additional training. Second, this deficit was reduced under higher intensities of electric shock. Overtraining on the task before the ablation had only a nonsignificant enhancing effect on retention levels. Extinction was always poorer following ablation, independent of the type of ablation, intensity of shock, degree of overtraining, and terminal retention level of performance. (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental study of unconscious influences: Ultrasound as a stimulus.

Used ultrasound as a stimulus to study its effects on behavior without S awareness. In Exp I evoked responses were elicited in 7 of 24 undergraduates by ultrasonic tones when Ss were reporting the presence of no stimulus. In Exp II with 20 male Ss, galvanic skin response conditioning to a compound stimulus made up of ultrasound and a red light resulted in shorter latencies to the compound stimulus than to the red light alone, during extinction. The differences did not appear among control Ss, supporting the occurrence of conditioning without awareness. In Exp III with 16 Ss, reaction-time performance was disrupted by providing ultrasound as an anticipatory cue for 1 of 2 lights over 150 trials and then reversing the ultrasound-light pairing. The ultrasound did not facilitate reaction time to the paired light during the 1st 150 trials, however. Results support learning without awareness, and the method is discussed as it might be extended to the study of unconscious influences and to clinical applications. (75 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appetitive learning and extinction in 11-day-old rat pups: Effects of various reinforcement conditions.

Studied the acquisition and extinction of approach behavior in 96 11-day-old albino Sprague-Dawley rat pups in 3 experiments. The reinforcement in Exps I & II was 15 sec of nonnutritive suckling on an anesthetized lactating female. In Exp I, detention duration, 0- or 15-sec in the goal box on nonreward (N) trials, was studied in 2 groups whose acquisition training consisted of alternating blocks of rewarded and nonrewarded trials with a short (5-sec) intertrial interval. Exp II combined an examination of the effect of detention length with whether or not the mother was physically present, though inaccessible, on N trials with partially or continuously rewarded groups. Detaining Ss on N trials slowed the rate of extinction when the mother was present but increased the rate of extinction when she was absent. There was no evidence of a partial reinforcement extinction effect in any of the groups. The effectiveness of 6 types of reinforcement on promoting acquisition of approach behavior was assessed in Exp III. Equally good acquisition, but differences in extinction was obtained with an adult conspecific as the reinforcer, independent of sex and suckling, but there was no acquisition of approach responding when a sibling or no conspecific was in the goal box. These data extend earlier findings of appetitive learning and extinction in infant rats. They do not support the view that inhibitory mechanisms are absent in the rat until the 3rd or 4th wk of life. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context specificity of conditioning, extinction, and latent inhibition.

Three experiments, using a conditioned suppression procedure with 112 male hooded Lister rats, examined the mechanisms of context specificity of conditioning, extinction, and latent inhibition. Exp I replicated previous demonstrations of context specificity of conditioning and extinction. Conditioning in one context did not necessarily transfer perfectly to another, and if extinction was carried out in a context different from that of conditioning, Ss showed a recovery of suppression when tested in the conditioning context. But both of these results disappeared when the familiarity and associative values of the 2 contexts were equated. Exp II replicated this failure to obtain context specificity of conditioning and extinction, but it did obtain context specificity of latent inhibition. Ss preexposed and conditioned to stimuli in the same context showed more profound latent inhibition than those preexposed and conditioned in different contexts. In Exp III, this effect was replicated. It is concluded that context specificity of conditioning or extinction may arise from the failure to control the associative status of the contexts used, whereas that of latent inhibition can best be explained by A. R. Wagner's (1976, 1981) theory of associative learning. Results offer no support for the view that, under conditions such as these, contexts serve as conditional cues, signaling the relationships between events occurring in their presence. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

False feedback and longevity of the conditioned GSR during extinction: Some implications for aversion therapy.

Investigated the effects of 2 cognitive variables on GSR extinction rates. Exp. I replicated findings that Ss made aware of the onset of nonshocked trials exhibited extinction of a conditioned emotional response more rapidly than Ss not made aware. Exp. I and II (80 and 20 Ss, respectively) further demonstrated that extinction, even under conditions of awareness, can be significantly retarded when false feedback concerning the S's current emotional responsivity is supplied during extinction trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of repeated testing on sexual behavior of the female rat.

Investigated effects of stimulation during repeated testing, using 24 female Sprague-Dawley rats in which intromission was prevented by a vaginal mask. Ss were ovariectomized and administered 1 mg of estradiol benzoate (EB) daily for 10 days (Exp I) or 5 mg of EB for 2 days (Exp II). Behavioral indices included lordosis quotient (a measure of sexual receptivity) and rejection quotient (a measure of social rejection of the male). Intensity and duration of lordosis gave additional measures. In Exp I hourly testing increased lordosis quotient and duration, especially in Ss receiving EB for 5 days; no effects of daily testing were shown. Exp II compared the behavior of Ss that were either handled hourly and tested hourly with the male rat or only handled hourly to the behavior of Ss that were tested and handled only once. Repeated testing and/or handling facilitated sexual responsiveness, while Ss that received neither treatment were sluggish in their social response to the male rat when they were tested, and were not sexually receptive. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction of an avoidance response following response prevention: Some parametric investigations.

Conducted 2 experiments to investigate parameters influencing the efficacy of response prevention. In Exp. I, with 44 female hooded rats, the amount of response prevention given to Ss who had learned to avoid electric shock in an automated apparatus was systematically varied. Increasing the duration of response prevention increased its effectiveness in hastening extinction. In Exp. II, with 31 Ss, the intensity of shock used in avoidance learning was parametrically varied. More intense shock diminished the efficacy of a fixed amount of response prevention. In both experiments, S's spontaneous behavior during response prevention was systematically recorded. The cessation of fear behavior and the occurrence of relaxation during response prevention were found to predict accurately the successful extinction of the avoidance response. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual differentiation of play behavior in the ferret.

Three experiments examined the endocrine mechanisms responsible for sex differences in prepubertal play behavior of ferrets. In Exp I, 6 gonadally intact adolescent males exhibited higher levels of "stand-over" behavior than 6 females did in tests between 63 and 123 days of age with gonadally intact female partners of the same age. In Exp II, with 69 Ss, those Ss exposed to androgen or to ovarian steroids over Days 5–20 of postnatal life subsequently exhibited significantly higher levels of stand-over behavior in tests with females than did control females gonadectomized on Day 5 and not given steroids. None of the Ss in Exp II exhibited levels of stand-over behavior comparable to those of the gonadally intact males in Exp I. In Exp III, with 36 Ss, males gonadectomized and implanted subcutaneously with testosterone capsules on Day 70 and tested with females at 84–96 days of age exhibited levels of stand-over behavior comparable to those observed in Exp I in gonadally intact males of the same age (Weeks 12–24). Males gonadectomized on Day 70 and given no hormone at testing exhibited significantly lower levels of this behavior. Significantly lower levels were also exhibited by males gonadectomized on Day 35 and females gonadectomized on Day 70, regardless of whether they were tested with testosterone present after Day 70. Sex differences in the expression of prepubertal play behavior of ferrets apparently result from differential exposure of males and females to androgen over an extended postnatal period. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ventral scent marking in Meriones unguiculatus may contribute to thermoregulation.

Conducted 3 experiments with adult male gerbils to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Exp I, with 16 Ss, showed that surgical removal of the ventral gland pad in 8 Ss reduced the amount of heat transferred by 50%, even though intact and glandless Ss did not differ in the average frequency of scent marking. Exp II, with the same 16 Ss used in Exp I, demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Exp III, with 14 Ss, showed that the pattern of ventral hair spread that occurred as an S moved over an object was different between intact and glandless Ss but that this difference did not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the hippocampus in blocking and conditioned inhibition of the rabbit's nictitating membrane response.

In Exp I, bilateral aspiration of the dorsal hippocampus produced a disruption of blocking of 30 New Zealand rabbits' nictitating membrane response in L. J. Kamin's (1968, 1969) 2-stage paradigm, but had no effect on the formation of a Pavlovian conditioned inhibitor in Exp II (27 Ss). Results of Exp I indicate that normal Ss and those with cortical lesions given conditioning to a light-plus-tone CS gave CRs to both light and tone during nonreinforced presentations of each (test phase). If, however, compound conditioning was preceded by tone acquisition, only the tone elicited a CR during testing; that is, blocking was observed. In Ss with hippocampal lesions, however, CRs were given to both light and tone during testing whether or not compound conditioning was preceded by tone acquisition. Data from Exp II show that Ss with hippocampal lesions could discriminate as well as normal Ss and those with cortical lesions between a light (CS+) and light plus tone (CS-). In addition, when the inhibitory tone was subsequently paired with the UCS in retardation testing, Ss in all 3 lesion conditions acquired the CR at the same rate. Thus, it appears that hippocampal lesions do not disrupt conditioned inhibition. Results are taken as support for the view that the hippocampus is responsible for "tuning out" stimuli that have no adaptive value to the organism. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learned helplessness and immunization: Sensitivity to response–reinforcer independence in immunized rats.

Exps I and II, with 62 male Holtzman rats, examined the learned helplessness and immunization effects using a test in which appetitive responding was extinguished by delivering noncontingent reinforcers. Contrary to learned helplessness theory, "immunized" Ss showed performance virtually identical to that of Ss exposed only to inescapable shock and different from that of nonshock controls. Exp II suggested that the helplessness effect and the lack of immunization were not due to direct response suppression resulting from shock. In Exp III, in which the immunization effect was assessed in 28 Ss by measuring the acquisition of a response to obtain food when there was a positive response–reinforcer contingency, immunization was observed. Results cannot be explained on the basis of proactive interference and instead suggest that Ss exposed to the immunization procedure acquired an expectancy of response–reinforcer independence during inescapable shock. Thus, immunization effects may reflect the differential expression of expectancies rather than their differential acquisition as learned helplessness theory postulates. (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Safety training: The elimination of avoidance-motivated aggression in dogs.

In Exp I, retrospective data of 92 cases on dangerously aggressive companion dogs demonstrated the avoidance nature of the aggressive response and its intractability to established counterconditioning treatments. In Exp II, safety training, a modified avoidance-learning procedure, resulted in complete and permanent elimination of aggression in all 36 dogs tested. In addition, it produced extinction-resistant prosocial avoidance responses, significant increases in the dogs' emotional stability, an avoidance-learning and safety acquisition response set, and improvements in measures of the dog's "carriage." Exp III (18 Ss) showed how effective safety training is when compared with other behavior modification techniques that, in theory, should have an impact on avoidance-motivated aggression. Exp IV (16 Ss) demonstrated the importance of using the conditioned safety cue as a positive reinforcement. The relationship of avoidance-motivated aggression to other forms of aggression is discussed, the theoretical concepts of behavioral balance and an avoidance-learning set are presented, and suggestions to improve the effectiveness of counterconditioning for human avoidance-motivated pathologies are offered. (90 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory preconditioning in rats following early visual deprivation.

Conducted 3 experiments in which a total of 131 light- and dark-reared (LR and DR) male hooded rats were given sensory preconditioning (SPC). In each experiment, Ss were presented with 2 stimuli either paired or unpaired, followed by conditioning to 1 and extinction on the other. 2 auditory stimuli were used in Exp. I. SPC was found for both LR and DR Ss, with no significant difference due to rearing condition either in acquisition or in the SPC test. In Exp. II, light and tone were employed; SPC was demonstrated and was more effective for LR than DR Ss. In Exp. III, rectangle stimuli were employed. The effect of SPC was evidenced in LR Ss; however, performance of DR Ss was not significantly different from that of controls. Results are discussed in terms of the effect of early visual deprivation on information-processing mechanisms. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of thermal and olfactory determinants of huddling in the rat.

In Exp I, in standardized tests of huddling behavior, 64 5-, 10-, 15-, and 20-day-old Sprague-Dawley rat pups spent substantial and equivalent amounts of time with an immobile rat or a heated, fur-covered tube, which suggests that the conspecific and inanimate stimuli were equally attractive to the pups. In Exp II, with 32 Ss, 2-choice preference tests showed developmental differences in attraction. Younger Ss preferred to huddle with the warmer, inanimate target, whereas older Ss preferred the conspecific. The emergent conspecific preference appears mediated by attraction to species odors. In Exp III (64 Ss), the 5- and 10-day-olds huddled equally with an immobile rat and an immobile gerbil (stimuli with similar thermal and tactile properties), but older Ss preferred the conspecific. In Exp IV, with 16 15-day-old and 16 20-day-old Ss, intranasal zinc sulfate treatment eliminated preference for the conspecific but did not disrupt huddling per se. Results from all experiments show that thermal cues were sufficient to elicit huddling at all ages, but olfactory cues became a more salient influence before weaning. An ontogenetic transition from "physiological" to "filial" huddling is discussed in terms of changes in sensory control of early behavior. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)