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At least 1,585 records · Page 88Linked to original sources
PubMed2005

Acute effects of d-amphetamine on the differential reinforcement of low-rate (DRL) schedule behavior in the rat: comparison with selective dopamine receptor antagonists.

Amphetamine and it analogs have been shown to affect operant behavior maintained on the differential reinforcement of a low-rate (DRL) schedule. The aim of the present study was to investigate what specific component of the DRL response is affected by d-amphetamine. The acute effects of d-amphetamine on a DRL task were compared with those of the selective dopamine D1 and D2 receptor antagonists, SCH23390 and raclopride, respectively. Pentylenetetrazole and ketamine were also used as two reference drugs for comparison with d-amphetamine as a psychostimulant. Rats were trained to press a lever for water reinforcement on a DRL 10-s schedule. Acute treatment of d-amphetamine (0, 0.5, and 1.0 mg/kg) significantly increased the response rate and decreased the reinforcement in a dose-related fashion. It also caused a horizontal leftward shift in the inter-response time (IRT) distribution at the doses tested. Such a shifting effect was confirmed by a significant decrease in the peak time, while the mean peak rate and burse response remained unaffected. In contrast, both SCH23390 (0, 0.05, and 0.10 mg/kg) and raclopride (0, 0.2, and 0.4 mg/kg) significantly decreased the total, non-reinforced, and burst responses. The de-burst IRT distributions were flattened out as shown by the dose-related decreases in the mean peak rate for both dopamine antagonists, but no dramatic shift in peak time was detected. Interestingly, neither pentylenetetrazole (0, 5, and 10 mg/kg) nor ketamine (0, 1, and 10 mg/kg) disrupted the DRL behavioral performance. It is then conceivable that d-amphetamine at the doses tested affects the temporal regulation of DRL behavior. The effectiveness of d-amphetamine is derived from its drug action as a psychostimulant. Taken together, these data suggest that different behavioral components of DRL task are differentially sensitive to pharmacological manipulation.

Animals↗
PubMedDate not supplied

[The role of motivation in the performance of a conditioned switching-over of the maze habit in ants Myrmica rubra after a change in the quality of the food reinforcement].

Active foragers Myrmica rubra were trained in a maze under conditions of different levels of colony need in food with carbohydrate (sugar syrup) or protein (ants Lasius niger pupae) reinforcement. Acquisition of the maze habit was better under conditions of reinforcement with pupae, especially by its time indices. Ants were able to modify the acquired habit when the reinforcement quality was changed. It was shown that learning was possible only when the colony and after a change pupae for the syrup was "hungry". Under these conditions, after a change of the syrup for pupae or visa versa the previously acquired optimum habit was transferred. Several hours later, with satiation of the colony, food reactions learned with protein reinforcement switched-over to "stochastic" non-optimized behavior with the dominance of exploratory reactions. Thus, it was shown that higher social insects ants were capable for conditioned switching-over. Different forms of this phenomenon depended on the level of the colony need in food and, consequently, on the level of the social food motivation of foragers ants.

Animals↗
PubMedDate not supplied

[The reinforcing action of stimulation of the mesocerebral area of the brain in the edible snail].

Reinforcing effect of extracellular stimulation of two brain zones on spontaneous opening of pneumostome was investigated in semi-intact preparation of the snail. It was found that mesocerebrum stimulation increased the frequency of the reinforced movement, but decreased the frequency of the same movement it its absence was reinforced. These results suggest positive reinforcing effect for this brain area involved in control of sexual behaviour. Different results were obtained for stimulation of rostral part of parietal ganglia where giant cells controlling avoidance behaviour are located. Stimulation of this area decreased the frequency of the ongoing spontaneous movements. Implications for the control of behaviour are considered.

Animals↗
PubMedDate not supplied

[Current problems in the reinforcement and regulation of goal-directed behavior].

Contemporary problems and arguable questions of reinforcement and self-regulation of animals behaviour and human activity are considered conformably to organization and analysis of results of conditioned experiments with probable reinforcement on the basis of semantic and pragmatic diagrams of conceptual space of decisions making. Situations are analyzed when the subject not simply "receives" the reinforcement but must actively "procure" (earn) the useful result. Scientific substantiation of conceptions of reinforcement and activity self-regulation is of considerable importance not only in the higher nervous activity physiology but also in psychology, economics and sociology for the decision of actual problems of organization of the processes of control in contemporary society of all mankind values and norms of behaviour.

Animals↗
PubMed1991

The reinforcing and subjective effects of morphine in post-addicts: a dose-response study.

The reinforcing and subjective effects of morphine were determined in five human volunteers with histories of i.v. heroin abuse. Subjects responded under a second-order schedule of i.m. injection. Under this schedule, every 100 lever presses produced a brief stimulus light [fixed ratio (FR) 100:s]; the 30th completion of the FR 100 requirement turned on the light for 15 min and the subject received an i.m. injection of morphine [FR 30 (FR 100:s)]. Once each weekday morphine or placebo was available under this schedule. Each drug dose was available for 1 week. Under these conditions placebo did not maintain responding; 3.75 mg of morphine maintained responding in four of five subjects, and higher morphine doses (7.5, 15 and 30 mg) maintained responding in all five subjects. Subjective effects were measured concurrently: these included measures of drug liking, the Morphine Benzedrine Group scale of the Addiction Research Center Inventory, drug detection and identification. Subjects did not report subjective effects different from placebo for the lowest dose of morphine; the intermediate doses of morphine produced inconsistent effects, and the highest dose of morphine occasioned reports of drug liking and "dope" identifications. These results indicate that there can be a significant dissociation of the reinforcing and the subjective effects of opioids, which has implications for theories of opioid abuse, particularly those assuming that the reinforcing effects are causally related to the euphoric effects of opioids. Furthermore, these results confirm that measures of reinforcing effects and measures of subjective effects do not necessarily lead to identical predictions when used to assess the liability for abuse of a substance.

Analgesia, Patient-Controlled↗
PubMed1991

Reinforcing staff performance in residential facilities: a survey of common managerial practices.

A national survey was conducted to investigate how managers in public residential facilities for persons with mental retardation attempt to reinforce work performance of direct-care staff. The reinforcement procedure reported most frequently by 460 managers was performance feedback (as opposed to monetary increments and time off). Essentially all managers reported using feedback, and virtually all of them reported that feedback was effective to varying degrees as a means of reinforcing staff performance. In response to an open-ended question regarding other procedures for reinforcing staff performance, they most frequently reported increasing staff involvement in management decision-making. Results were discussed in light of future research needs for improving staff work performance and incorporating results of management research into routine management practices.

Employee Incentive Plans↗
PubMed1991

Relative and absolute reinforcement frequency as determinants of choice in concurrent variable interval schedules.

Rats were trained under concurrent schedules consisting of two equal variable interval component schedules providing sucrose solutions of different concentrations (0.6 M, 0.2 M; 50 microliters in each case) as the reinforcers. The mean interreinforcement interval specified by the schedules was varied from 10 to 640 sec. Absolute response rate in each component was an increasing hyperbolic function of reinforcement frequency. Relative response rate and relative time allocation revealed a consistent preference for the more concentrated solution; neither measure of preference was systematically related to reinforcement frequency. The results are consistent with Baum and Rachlin's (1969) extension of the matching law, and with a derivation of the matching law from the hyperbolic relation between absolute response rate and reinforcement frequency in variable interval schedules (Herrnstein, 1970).

Animals↗
PubMed1989

Operant conditioning of head-waving in Aplysia. III. Cellular analysis of possible reinforcement pathways.

Operant conditioning of the head-waving response in Aplysia, as well as conditioning of the electrical activity of identified neck muscles, can be induced readily when bright light is used as aversive reinforcement (Cook and Carew, 1986, 1989b). A cellular analysis of this type of operant conditioning requires an understanding of the neural circuitry that underlies the reinforcement pathways involved in the conditioning. In the present paper we describe a cellular analysis of possible reinforcement pathways that mediate the aversive effects of bright light in the CNS of Aplysia. Using a semi-intact "split-body" preparation, we explored the effects of bright light on the operant response pathway by recording intracellularly from identified pedal neck and body wall motor neurons, which contribute to the operant response. In these experiments we identified 2 light-sensitive pathways. One pathway, from the eyes and rhinophores, mediated functional inhibition of light-induced excitation of pedal motor neurons. The other pathway, from the oral veil (cerebral ganglion nerves C1-C3) mediated significant excitation of the same motor cells. Randomly occurring blank trials ruled out the possibility that the light-induced effects were due to sampling bias. Finally, surgical isolation of the CNS from the periphery showed that none of the effects of light were due to direct illumination of central neurons. This identification of candidate reinforcement pathways will facilitate a cellular analysis of operant conditioning of head-waving in Aplysia.

Animals↗
PubMedDate not supplied

[Secondary-reinforcing effects of opiate agonists in the mouse].

Comparative examination of secondary-reinforcing properties of opiate agonists morphine, nalorphine, pentazocine and phencyclidine was carried out on mice using procedure of place preference conditioning in an automatic shuttle-box. Morphine, phencyclidine and pentaxocine (but not nalorphine) produced strong dose-dependent secondary-reinforcing effects. Special features of behavioural manifestations of their secondary-reinforcing action were analyzed in aspect of changes in temporal asymmetry and attendant locomotor activity of animals in the shuttle-box. On the basis of the obtained and literature data, it is suggested that mu- and sigma-opiate receptors mediate secondary-reinforcing effects of opiate agonists.

Animals↗
PubMed1988

Reinforcing effects of caffeine in humans.

The reinforcing and subjective effects of caffeine were studied under double-blind conditions in 12 normal humans. After 2 forced exposure days on which subjects received color-coded capsules containing either caffeine (100, 200, 400 or 600 mg) or placebo, subjects had a choice day on which they chose which one of the two types of color-coded capsules would be ingested. Subjects were exposed to 10 experimentally independent choices (i.e., involving exposure and choice between novel color-coded capsule conditions) at each of several dose levels. All forced exposure and choice opportunities occurred when subjects were overnight abstinent from their normal dietary caffeine intake (mean, 116 mg/day). Significant caffeine positive reinforcement was demonstrated in 5 of 12 subjects at one or more doses. Percentage of selection of caffeine was inversely related to dose, with four subjects showing significant caffeine avoidance at 400 and/or 600 mg. Choice behavior was correlated positively with feelings of contentedness and was correlated negatively with prestudy trait anxiety scores and with ratings of capsule disliking. Compared to placebo, caffeine produced increases in subjective ratings indicating arousal while producing decreases in headache and "craving" for caffeine-containing foods, even at the lowest dose of 100 mg. At higher doses caffeine produced dysphoric anxiety-like subjective effects. Overall, this study provides the first demonstration in humans of the positive reinforcing effects of caffeine alone (i.e., in capsules) and documents individual differences among normal subjects in both caffeine positive reinforcement and caffeine avoidance.

Adult↗
PubMed1987

Relationship between minimum reinforcing doses and injection speed in cocaine and pentobarbital self-administration in crab-eating monkeys.

The relationship between minimum reinforcing doses and injection speed was investigated by using 2 levels of speeds in experiments on self-administration of cocaine or pentobarbital in 2 crab-eating monkeys each. The experiments were conducted under a fixed ratio (FR) 1 schedule with 30-min time-out after each drug injection, wherein the drugs and saline were made available for alternate 5-day periods. The minimum reinforcing doses at each injection speed were determined by the titration procedure in which the presence or absence of reinforcing effect at a particular drug dose was judged based on comparison of the self-administration rate at that dose with the rate in the preceding saline period. The results showed that the minimum reinforcing doses of cocaine and pentobarbital tended to be higher in inverse proportion to the injection speed of the drugs.

Animals↗
PubMedDate not supplied

[Probability analysis of elements of rat behavior after sudden and signalled interruption of food reinforcement].

Probability analysis was carried out of the appearance of single elements of rats behaviour in the process of extinction of a conditioned alimentary motor reflex. The dynamics of effector behavioural components at a sudden cessation of reinforcement (usual schedule of extinction) was compared with cessation of reinforcement signalled by a previously differentiated signal and with reinforcement cessation preceded by a stimulus initially unknown to the animal. If the reinforcement cessation is signalled by a previously differentiated (negative) stimulus, in response to its action the animals "loose the aim", what is revealed in a rapid complete reduction of all elements of the goal-directed alimentary behaviour. Obviously differentiation signal actualises the memory trace of "nonreinforcement" which was formed in the previous negative experience of the animal; this is revealed in accelerated inhibition of the alimentary motor reflex under extinction.

Animals↗
PubMed1985

Instructions control whether nicotine will serve as a reinforcer.

Three studies examined self-administration of nicotine among exsmokers given concurrent access to nicotine (2 mg) and placebo gums during the first 2 weeks of abstinence from smoking. In Study 1 subjects were told they would receive either nicotine or placebo gum. With this instructional set, nicotine served as a reinforcer; i.e., subjects consistently self-administered nicotine but not placebo gum. However, subjects could discriminate gums on the basis of side-effects; thus, the ability of nicotine to serve as a reinforcer may have been due, not to its psychoactive effects, but rather because subjects believed the gum with more side-effects to be the active gum. In Study 2 we attempted to change this belief by telling subjects they would receive either the marketed nicotine gum or a new nicotine gum that is as effective as the marketed gum but has less side-effects (i.e., placebo). In Study 3 we attempted to change the belief by telling subjects that placebo gum had more side-effects than nicotine gum. With these two instructional sets, the stimulus properties of nicotine did not serve as reinforcer; i.e., subjects self-administered equal amounts of nicotine and placebo gums. To our knowledge, this is the first demonstration that instructions can control whether a drug will serve as a reinforcer.

Discrimination Learning↗
PubMed1985

Reinforcing stimulus properties of endocoids.

Intracranial self-administration methodologies can be used to directly assess the neurobiological substrates of the reinforcing stimulus properties of drugs and endogenous ligands that may bind to receptors initiating these neuronal events. The reinforcing properties of the intracranial infusion of methionine enkephalin into the nucleus accumbens where it is released from nerve endings were demonstrated. The mechanisms of the reinforcing stimulus resulting from the intracranial self-administration of cocaine into the medial prefrontal cortex were shown to require presynaptic dopaminergic intervations and postsynaptic dopaminergic D2 receptors. The endogenous ligand that competes for cocaine binding may initate a reinforcing stimulus through similar mechanisms which could be directly assessed with intracranial self-administration procedures.

Animals↗
PubMed1974

Elaboration of conditioned alimentary reflexes having different probabilities of reinforcement in rats with hippocampal lesions.

A motor alimentary conditioned reflex was elaborated in hippocampectomized and intact albino rats. Food reinforcement followed 100 percent, 50 percent, 33 percent or 25 percent of conditional stimulus presentations (click from a rotating food box). No differences were found in the rate of conditioned alimentary reflex elaboration between the hippocampectomized and control rats at 100 percent and 50 percent reinforcement, although the time-courses of formation of the conditioned reflex connection differed substantially. With low reinforcement probabilities (33 percent and 25 percent) the operated rats, unlike the intact ones, exhibited no adequate responses throughout the 10 experimental days. The results obtained corroborate an earlier suggestion that the hippocampus is involved in the organization of behavior the reinforcement probability of which is unknown or relatively low.

Acoustic Stimulation↗
PubMed1983

Reinforcing properties of stereoisomers of the putative sigma agonists N-allylnormetazocine and cyclazocine in rhesus monkeys.

There are many similarities in the effects of phencyclidine (PCP) and opioids with sigma agonist activity such as N-allylnormetazocine (SKF-10,047) and cyclazocine. Yet PCP and sigma agonists differ in reinforcing properties. PCP is reliably self-administered in animal models and has abuse liability in humans, whereas (+/-)-N-allylnormetazocine and (+/-)-cyclazocine are not self-administered or abused. Inasmuch as other research has demonstrated differences in the selectivity of PCP-like effects of the stereoisomers of opioids, this study compared the reinforcing properties of PCP to the reinforcing properties of isomers of N-allylnormetazocine and cyclazocine. Rhesus monkeys were trained to lever-press on a fixed-ratio 10 schedule for i.v. cocaine (50 micrograms/kg/injection). During substitution tests, cocaine was replaced with various doses of test drugs or vehicle. The drugs tested were PCP, (+/-)-N-allylnormetazocine, (-)-N-allylnormetazocine, (+)-N-allylnormetazocine, (+/-)-cyclazocine, (-)-cyclazocine and (+)-cyclazocine. PCP and the (+)-isomers of both benzomorphans, at one or more doses, were self-administered at rates which exceeded rates maintained by vehicle and which equaled or exceeded cocaine-maintained base-line rates. Neither the racemates nor the (-)-isomers of N-allylnormetazocine or cyclazocine were self-administered by the monkeys at rates which were greater than vehicle control levels of responding. Reinforcing doses of the three compounds resulted in injections evenly distributed across the 60-min session in a pattern similar to cocaine self-administration, whereas the racemic mixtures and the (-)-isomers produced negatively accelerated patterns of injections which resembled typical saline patterns of extinction responding. These data provide further evidence that the (+)-isomers of sigma agonists are more selective for PCP-like effects than the (-)-isomers in monkeys.

Animals↗
PubMed1980

Effects of mental age, knowledge of results, and social reinforcement on motor performance.

The effects of mental age (MA), knowledge of results, and social reinforcement on performance on a speed motor task by mildly mentally retarded children was investigated. Significant main effects were found for the variables of MA and social reinforcement and significant interactions for the MA x Social-Reinforcement conditions and the Knowledge of Results x Social-Reinforcement conditions. Post hoc analysis indicated that high-MA subjects performed significantly better under verbal praise conditions than did low-MA subjects. Also, knowledge of results was most effective in the presence of verbal praise. We suggested that verbal praise sensitized subjects to attend to the knowledge of results cue.

Adolescent↗
PubMed1994

Potentiation of lateral hypothalamic and midline mesencephalic brain stimulation reinforcement by nicotine: examination of repeated treatment.

The effects of nicotine (0.025-0.8 mg/kg s.c.) were assessed daily for 10 days on lever pressing maintained by reinforcement of lateral hypothalamic or midline mesencephalic brain stimulation in rats. Similar effects were seen but slightly higher doses were needed with lateral hypothalamic stimulation. With each stimulation site, the lower doses produced parallel leftward shifts in the rate-frequency functions. The higher doses produced sedative effects and cessation of responding in some animals on the first 2 or 3 days of testing but tolerance to this effect was seen. Parallel leftward shifts were produced from day 4 on. Although there was tolerance to the sedative effects, there was neither tolerance nor sensitization to the ability of nicotine to produce leftward shifts in the rate-frequency functions of performing animals. The sensitivity to nicotine of the reinforcing actions of both lateral hypothalamic and medial mesencephalic brain stimulation is consistent with evidence that suggests that stimulation at these two sites activates common reinforcement-related brain circuitry. The fact that nicotine causes parallel leftward shifts in the brain stimulation rate-frequency functions suggests synergism of a nicotinic action with the reinforcing action of the brain stimulation.

Animals↗