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PubMed2001

The role of basal ganglia in reinforcement learning and imprinting in domestic chicks.

Effects of bilateral kainate lesions of telencephalic basal ganglia (lobus parolfactorius, LPO) were examined in domestic chicks. In the imprinting paradigm, where chicks learned to selectively approach a moving object without any explicitly associated reward, both the pre- and post-training lesions were without effects. On the other hand, in the water-reinforced pecking task, pre-training lesions of LPO severely impaired immediate reinforcement as well as formation of the association memory. However, post-training LPO lesions did not cause amnesia, and chicks selectively pecked at the reinforced color. The LPO could thus be involved specifically in the evaluation of present rewards and the instantaneous reinforcement of pecking, but not in the execution of selective behavior based on a memorized color cue.

Animals↗
PubMed2000

Alternative reinforcers differentially modify cocaine self-administration by humans.

Six experienced cocaine smokers (two men, four women) participated in an inpatient study to compare self-administration of smoked cocaine when either a $5 money or merchandise voucher was available as an alternative reinforcer. A six-trial choice procedure was used, with sessions consisting of (1) one sample trial, where participants received the cocaine dose and the alternative reinforcer available that day, and (2) five choice trials, where participants chose between the available cocaine dose and the alternative reinforcer. There were eight sessions: in separate sessions, each dose of cocaine (0, 12, 25, 50 mg) was paired with a money voucher and with a merchandise voucher. The choice to self-administer cocaine significantly increased with escalating cocaine doses, and significantly less cocaine was self-administered when money vouchers were available as compared to merchandise vouchers. These data demonstrate that money vouchers are a more effective alternative reinforcer than merchandise vouchers in cocaine abusers.

Adult↗
PubMed2001

Discrimination of pentobarbital doses and drug mixtures under fixed-ratio and fixed-interval reinforcement schedules.

Pigeons were trained to discriminate among 5 mg/kg pentobarbital, 10mg/kg pentobarbital, and saline, under either fixed-interval (FI) or fixed-ratio (FR) reinforcement schedules. When baseline responding stabilized, a higher percentage of responses occurred on the key that produced the reinforcer under the FR schedule than under the FI schedule. After low doses of pentobarbital, responding shifted from the saline key to the 5 mg/kg pentobarbital key; at higher doses of pentobarbital responding shifted to the 10mg/kg pentobarbital key under both schedules. After low doses of ethanol and chlordiazepoxide, responding shifted from the saline key to the 5 mg/kg pentobarbital key, but after high doses of these drugs, responding continued to occur on the 5 mg/kg pentobarbital key under both reinforcement schedules. A 5 mg/kg dose of pentobarbital increased responding on the 10 mg/kg pentobarbital key when it was combined with pentobarbital, ethanol or chlordiazepoxide. Phencyclidine and D-amphetamine produced responding largely on the saline key under both reinforcement schedules. Under the FR schedule, pentobarbital dose-response curves were usually quantal, whereas under the FI schedule the pentobarbital dose-response curves usually were graded.

Animals↗
PubMed2003

Salsolinol produces reinforcing effects in the nucleus accumbens shell of alcohol-preferring (P) rats.

BACKGROUND: The formation of salsolinol (SAL) has been hypothesized to be a factor contributing to alcoholism and alcohol abuse. If SAL is formed under chronic alcohol-drinking conditions, then it may contribute to alcohol addiction by being rewarding itself. Because SAL can be formed by the nonenzymatic condensation of acetaldehyde with dopamine, the reinforcing effects of SAL were tested in the nucleus accumbens shell, a dopamine-rich site considered to be involved in regulating alcohol-drinking behavior. METHODS: The intracranial self-administration technique was used to test the reinforcing properties of SAL. Adult, female alcohol-preferring (P) rats were stereotaxically implanted with guide cannulae aimed at the nucleus accumbens shell. After 7 to 10 days to allow recovery from surgery, P rats were attached to the electrolytic microinfusion transducer system, placed in two-lever experimental chambers, and allowed to respond for the self-infusion of 100 nl of modified artificial cerebrospinal fluid (aCSF) or 0.03, 0.3, 3.0, or 12.5 microM SAL (3-1250 fmol/100 nl). Sessions were 4 hr in duration and were conducted in the dark cycle every 48 hr. The effects of coinfusing 10 to 400 microM sulpiride (given in sessions 5 and 6 after four acquisition sessions) on the intracranial self-administration of 3.0 microM SAL were tested in a separate experiment. RESULTS: P rats given 0.3 to 12.5 microM SAL received significantly more infusions per session than did the group given aCSF alone (e.g., 50 infusions for 3.0 microM SAL versus 10 or fewer infusions for the aCSF group) and responded significantly more on the active than inactive lever. Coinfusion of 100 or 400 microM sulpiride reduced the responding on the active lever (80-100 responses/session without sulpiride) to levels observed for the inactive lever (fewer than 10 responses/session with sulpiride). This effect was reversible because giving SAL alone in session 7 reinstated responding on the active lever. CONCLUSIONS: SAL is reinforcing in the nucleus accumbens shell of P rats at concentrations that are pharmacologically possible, and these reinforcing actions are mediated in part by D2/D3-like receptors.

Alcohol Drinking↗
PubMed2004

Nitric oxide synthesis inhibition attenuates conditioned reinstatement of ethanol-seeking, but not the primary reinforcing effects of ethanol.

BACKGROUND: Nitric oxide (NO) signaling has been implicated in regulating aspects of the reinforcing and addictive actions of cocaine. These experiments were designed to examine whether NO-dependent neurotransmission also participates in mediating the addictive actions of another drug of abuse, ethanol, with emphasis on both the primary reinforcing effects of ethanol and the incentive motivational effects of ethanol-related contextual stimuli. METHODS: Male Wistar rats were operantly trained to orally self-administer 10% (w/v) ethanol in daily 30-min sessions and to associate distinct discriminative stimuli with the availability of ethanol (S+) versus nonreward (S-). Rats were treated with the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 0, 10, or 40 mg/kg intraperitoneally) 30 min before self-administration tests that were conducted after establishment of stable levels of daily ethanol intake and conditioned reinstatement tests that were performed after extinction of ethanol-maintained operant responding. RESULTS: L-NAME did not alter the primary reinforcing effects of ethanol in self-administration tests. In contrast, L-NAME dose-dependently attenuated the recovery of extinguished responding induced by the ethanol S in the absence of ethanol availability during reinstatement tests. CONCLUSIONS: These results suggest that the NO system does not play a role in behavior reinforced directly by ethanol. However, the results implicate NO-dependent neurotransmission in alcohol-seeking responses elicited by drug-related contextual stimuli.

Alcohol Drinking↗
PubMed2005

Reinforcing mood effects of alcohol in coping and enhancement motivated drinkers.

BACKGROUND: People may be motivated to drink because of differential sensitivities to the rewarding outcomes of alcohol consumption. Previous research has demonstrated that alcohol may produce both potentially positive reinforcing effects (i.e., increased elation; Conrad et al., 2001) and potentially negative reinforcing effects (i.e., anxiolytic effects; Levenson st al., 1980). It was desired to test the effects of alcohol on mood in a sample of two groups of drinkers that report different motivations for alcohol use. It was hypothesized that both potentially positive and negative reinforcing mood effects would be observed and that these effects would be moderated by drinking motive. METHODS: Twenty-four drinkers with Coping Motives (CMs) and 24 drinkers with Enhancement Motives (EMs) were randomly assigned to either an alcohol condition (target blood alcohol level of 0.08%) or a placebo condition. Participants used the Profile of Mood States-Bipolar (Lorr, 1983) to report their mood at (1) sober baseline, (2) after beverage consumption, and (3) during anticipation of a self-disclosing speech (a stressor). RESULTS: As hypothesized, after drinking, those in the alcohol group reported increased feelings of elation and energy relative to sober baseline. Those receiving alcohol also reported feeling more confused and anxious after beverage consumption. Also as hypothesized, participants receiving alcohol reported feeling increased sedation during anticipation of the stressor, whereas those receiving placebo reported increased energy during this period. Contrary to the hypothesis, none of these effects were moderated by drinking motive. CONCLUSIONS: Although potentially positive and negative reinforcing mood effects of alcohol were observed, CM and EM drinkers were not differentially sensitive to these effects. However, it is possible that EM drinkers may highly value the baseline stimulating effects of alcohol, whereas CM drinkers may highly value the anxiolytic effects that were observed during anticipation of the stressor.

Adaptation, Psychological↗
PubMed2005

Reinforcement of rat hippocampal LTP by holeboard training.

Hippocampal long-term potentiation (LTP) can be dissociated in early-LTP lasting 4-5 h and late-LTP with a duration of more than 8 h, the latter of which requires protein synthesis and heterosynaptic activity during its induction. Previous studies in vivo have shown that early-LTP in the dentate gyrus can protein synthesis-dependently be transformed (reinforced) into late-LTP by the association of arousing novel environmental stimuli. Here we show that consolidation of spatial memory also reinforces early-LTP in the dentate gyrus. Both memory consolidation and LTP-reinforcement depend on protein synthesis. Four groups of animals were trained by five, seven, eight or 10 trials, respectively, to recognize a fixed pattern of baited holes. The last trial was performed 15 min after tetanus. Errors of long-term reference memory during the last trial were significantly decreased only in the eight- and 10-trial experimental groups compared to pseudo-trained animals. In correlation to this learning effect we found a reinforcement of early-LTP only in these experimental groups compared to controls. The data suggest that the synthesis of new proteins required for spatial reference-memory formation also contributes to LTP maintenance in the hippocampal dentate gyrus.

Animals↗
PubMed2004

Prize reinforcement contingency management for treating cocaine users: how low can we go, and with whom?

AIMS: This study evaluated the efficacy of a low-cost, prize reinforcement contingency management (CM) intervention for reducing cocaine use. SETTING: Community-based treatment centers. PARTICIPANTS AND DESIGN: Cocaine-abusing out-patients (n = 120) were assigned randomly to one of three 12-week conditions: standard treatment, standard treatment plus CM with an expected maximum of $80 of reinforcement or standard treatment plus CM with an expected maximum of $240 of reinforcement. INTERVENTION: In the CM conditions, patients earned the opportunity to win prizes for submitting negative urine samples and completing goal-related activities. MEASUREMENTS: Drug use was measured at intake and throughout a 3-month treatment period. FINDINGS: Patients in the $240 CM condition achieved more abstinence than patients in the standard condition. Patients who initiated treatment with positive urinalysis results were most responsive to the CM intervention, with the $240 CM condition engendering the best effects in this subgroup. In contrast, patients who initiated treatment with negative urinalysis results generally remained abstinent during treatment, regardless of treatment assignment. On average, patients in the two CM conditions earned $36 and $68 in prizes. CONCLUSIONS: This study suggests that prize reinforcement CM may be suitable for community-based settings, and beneficial effects may be magnitude-dependent in more severe patients.

Adult↗
PubMed2004

Measuring the emergence of tobacco dependence: the contribution of negative reinforcement models.

This review of negative reinforcement models of drug dependence is part of a series that takes the position that a complete understanding of current concepts of dependence will facilitate the development of reliable and valid measures of the emergence of tobacco dependence. Other reviews within the series consider models that emphasize positive reinforcement and social learning/cognitive models. This review summarizes negative reinforcement in general and then presents four current negative reinforcement models that emphasize withdrawal, classical conditioning, self-medication and opponent-processes. For each model, the paper outlines central aspects of dependence, conceptualization of dependence development and influences that the model might have on current and future measures of dependence. Understanding how drug dependence develops will be an important part of future successful tobacco dependence measurement, prevention and treatment strategies.

Adolescent↗
PubMed1988

A comparison of two behaviour reduction procedures: traditional extinction alone and interpolated reinforcement followed by extinction.

Extinction responding of children with severe retardation was compared when one component of a multiple schedule (VR-20/VR-20) was interpolated with one session of additional reinforcement. Either variable ratio 10 (VR-10), variable ratio 5 (VR-5) or continuous reinforcement (CRF) were interpolated in one component prior to extinction in both. Interpolated reinforcement resulted in an extinction process at least as efficient as traditional methods. Total responding in the VR-10 and VR-5 components was less than in the comparable unchanged components. Results support and extend research with animals and humans. Results also suggest the feasibility of using such a procedure to gain control of behaviours that are controlled by intermittent schedules of reinforcement, are under multiple or inconsistent stimulus control or occur infrequently.

Behavior Therapy↗
PubMed1978

Effects of morphine, naloxone, d,l-cyclazocine, and d-amphetamine on behaviour controlled by a schedule of interresponse time reinforcement.

The separate effects of graded doses of morphine, naloxone, d,l-cyclazocine, and d-amphetamine on responding maintained by a differential reinforcement of low rate schedule of food presentation were examined in rats. Morphine did not alter response rates at doses of 1--5.6 mg/kg; at 10 mg/kg a 57% decrease in responding was observed and behaviour was even more severely depressed by 30 mg of morphine per kilogram. Naloxone did not affect responding at doses ranging from 0.1 to 10 mg/kg. d,l-Cyclazocine at doses of 3 and 5.6 mg/kg induced substantial increases in responding not observed when the dose was increased to 10 mg/kg. Cyclazocine, as well as morphine, produced dose-dependent decreases in the number of reinforcements per session. d-Amphetamine exerted a biphasic effect on responding; small doses increased response rates (0.3--3 mg/kg) and responding was suppressed by the drug at a dose of 10 mg/kg. Behaviourally active doses of d-amphetamine caused a dose-dependent reduction in the number of reinforcements per session. Naloxone at otherwise inactive doses (1--10 mg/kg) was found, in separate experiments, to antagonize the rate-decreasing effects of morphine, and to reduce the rate-increasing effects of d-amphetamine. The latter effect is not easily interpreted but confirms and extends other research employing rats in which naloxone was found to reduce the rate-increasing effects of small doses of d-amphetamine upon locomotor activity and responding maintained by a continuous electric-shock postponement procedure. In additional experiments morphine was given daily for 25 consecutive sessions at a dose of 30 mg/kg, 5 min preceding each test session. Responding was suppressed throughout this period and the dose of morphine given before each session was reduced to 10 mg/kg for 35 further sessions. Tolerance to the rate-decreasing effects of morphine was demonstrated; naloxone given in conjunction with morphine (10 mg/kg) in morphine-tolerant rats restored to control values the number of reinforcements per session without causing significant change in overall rates of responding. Few experiments have dealt previously with the development of tolerance to the behavioural effects of morphine under comparable dose regimens, time-course relationships, or behavioural testing procedures. Systematic analyses of these interrelated variables are needed since it is now evident that the schedule employed to maintain responding itself exerts significant effects.

Animals↗
PubMed2001

Reinforcing effects of MDMA ("ecstasy") in drug-naive and cocaine-trained rats.

3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is one of the most prevalent illegal drugs of abuse among European adolescents, a population not generally experienced with respect to "hard" drugs such as cocaine. We, therefore, determined the reinforcing effect of intravenously self-administered MDMA in a fixed ratio 1 time-out 150 s schedule of reinforcement in rats that were truly drug naive and compared it to cocaine-trained rats. The reinforcing effect of MDMA [0.032-10 mg/(kg.injection)] did not differ between drug-naive rats and cocaine-trained ones. MDMA sensitized the animals to its own rate-increasing effect but not to that of cocaine. When MDMA was tested after cocaine, there was no carryover of cocaine's reinforcing effect to that of MDMA, suggesting that MDMA and cocaine produce distinct interoceptive stimuli in rats.

Animals↗
PubMed2002

Multiple model-based reinforcement learning.

We propose a modular reinforcement learning architecture for nonlinear, nonstationary control tasks, which we call multiple model-based reinforcement learning (MMRL). The basic idea is to decompose a complex task into multiple domains in space and time based on the predictability of the environmental dynamics. The system is composed of multiple modules, each of which consists of a state prediction model and a reinforcement learning controller. The "responsibility signal," which is given by the softmax function of the prediction errors, is used to weight the outputs of multiple modules, as well as to gate the learning of the prediction models and the reinforcement learning controllers. We formulate MMRL for both discrete-time, finite-state case and continuous-time, continuous-state case. The performance of MMRL was demonstrated for discrete case in a nonstationary hunting task in a grid world and for continuous case in a nonlinear, nonstationary control task of swinging up a pendulum with variable physical parameters.

Humans↗
PubMed2006

Physical exercise as a reinforcer to promote calmness of an ADHD child.

Age-appropriate reinforcers have been found to be effective in promoting attentiveness and calmness with children with attention deficit hyperactivity disorder (ADHD). The present study with a 4-year-old ADHD boy found attentive calmness was substantially increased from a mean of about 3 seconds per trial to the maximum scheduled duration of 60 seconds by using a scheduled period of physical activity as the reinforcer for the attentive-calmness. These results suggest the possible use of this type of reinforcer as an addition or substitution for the usual reinforcers in contingency management with ADHD children.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

A study on the effects of some reinforcers to improve performance of employees in a retail industry.

Two field experiments were conducted in the Business Information Technology Department of a major retail industry to analyze the impact of positive task performance reinforcers. The employees were divided into two broad groups - those performing complex tasks and those performing relatively simpler tasks. The first group was further divided into two subgroups, one being reinforced with money and paid leave and the other with feedback. Both the subgroups showed a significant improvement in performance behavior. However, feedback had a stronger effect on task performance even after the reinforcement was withdrawn. The second group of employees was allowed to choose reinforcers of their liking. Two simple techniques, a casual dress code and flexible working hours chosen by them, had a positive effect on their performance, which continued even after 6 months into the intervention. Besides, the procedure for the second group required no monetary or work-time loss to the employer.

Adult↗
PubMed1996

Behavioral momentum. Implications and development from reinforcement theories.

Historical and contemporary theories of reinforcement, as well as the clinical application of reinforcement principles to behavior modification and therapy, are critically analyzed and discussed. A new behavioral approach to studying the allocation of behavior under changed environmental constraints, termed behavioral momentum, is also presented. Whereas traditional behavioral analysis has emphasized the role of response rate as an index of response probability and response strength, more recent studies have addressed the persistence of behavior under altered environmental conditions and reinforcement contingencies. In terms of behavior modification and therapy, issues such as generalizability and relapse prevention have major implications for the type and length of behavioral intervention strategies employed. The behavioral momentum model analyzes operant behavior not only in terms of its response rate but also in relation to its persistence under changed environmental constraints. The authors discuss the applicability of this recent addition to reinforcement theories in context of its implications for behavior modification and therapy.

Behavior Therapy↗
PubMed1997

A simple reinforcement strategy for increasing attendance at a fitness facility.

The purpose of the present study was to examine the effect of a previously untested reinforcement strategy (i.e., 1 month's free membership) on attendance at a fitness facility. Participants were paying members of a fitness facility randomly assigned to control (n = 100), placebo (n = 100), and reinforcement (n = 100) conditions. The control condition received no intervention; the placebo condition received a letter by mail; and the reinforcement condition received the same letter by mail, except that it included an additional paragraph instructing them that they could earn 1 month's free membership if they attended the fitness facility at least 12 times in the next month. Attendance was monitored for 1 month baseline and postintervention by using the facility's computer system. Analysis of variance, t tests, and chi-square analysis all revealed that the reinforcement condition had the best attendance record during the intervention period. These preliminary results shed some light on increasing attendance at a fitness facility. Discussion highlighted the practical implications of the findings and offered directions for future research.

Adult↗
PubMed2004

Role of gamma-aminobutyric acid (GABA) and metabotropic glutamate receptors in nicotine reinforcement: potential pharmacotherapies for smoking cessation.

Previous work indicated a role for GABA and glutamate in the reinforcing effects of drugs of abuse. The present studies assessed the effects of GABAergic and glutamatergic manipulations on the reinforcing effects of nicotine as assessed by intravenous nicotine self-administration. Male Wistar rats were allowed to self-administer either of two nicotine doses under a fixed ratio or a progressive ratio schedule of reinforcement. The effects of a glutamatergic compound on nicotine self-administration in male DBA/2J mice were also explored. Finally, to assess for nonspecific effects of the drug manipulations, the effects of all test compounds on responding maintained by a food reinforcer were investigated. The pharmacological manipulations used were: gamma-vinyl-GABA (vigabatrin or GVG), an irreversible inhibitor of GABA transaminase, the GABAB receptor agonists (-)baclofen and CGP44532, and the metabotropic glutamate receptor 5 (mGluR5) antagonist MPEP. GVG, CGP44532, and (-)baclofen dose-dependently decreased nicotine self-administration on the fixed-ratio schedule, but also decreased food-maintained responding. Furthermore, CGP44532 decreased breakpoints for nicotine and food at identical doses under the progressive-ratio schedule. MPEP dose-dependently decreased nicotine self-administration with no effect on food-maintained responding in rats. MPEP also decreased nicotine self-administration in the mice. These results demonstrate that activation of GABAB receptors or blockade of mGluR5 decreased nicotine self-administration. Although there was some selectivity for the effects of the GABAergic manipulations, there was clear selectivity of the effects of MPEP on nicotine- versus food-maintained responding. Thus, compounds that increase GABAergic neurotransmission and antagonists at mGluR5 have potential as anti-smoking medications for humans.

Animals↗