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PubMed2004

Local proactive interference in delayed matching to sample: the role of reinforcement.

Discriminability in delayed matching to sample was lower when the samples on consecutive trials differed compared with when samples on consecutive trials were the same. This local proactive interference occurred when correct choices on the previous trial were reinforced but not when correct choices on the previous trial were not reinforced. When the choice on the previous trial was incorrect, discriminability was higher on different consecutive trials than on same trials. These effects were amplified by varying the ratio of reinforcers for correct choices, as predicted by a model that attributes local proactive interference to an interaction between control by the sample on the current trial and the influence of reinforcers for correct choices on previous trials.

Animals↗
PubMed2003

Lack of depression-like effects of saccharin deprivation in rats: forced swim test, differential reinforcement of low rates and intracranial self-stimulation procedures.

In humans and laboratory animals, drug withdrawal often is associated with depression-like behaviors. In the present study, rats had unlimited free-choice access to water and a saccharin-containing solution before being subjected to repeated episodes of saccharin deprivation. Saccharin deprivation (1) reduced immobility time in the forced swim test, (2) increased reinforcement rate in rats trained to lever-press under the differential reinforcement of a low-rate (72-sec) schedule of food reinforcement, and (3) lowered intracranial self-stimulation thresholds in a discrete-trial current titration procedure. Taken together, these findings suggest that deprivation from a nondrug reinforcer, saccharin, is not associated with depression-like behaviors. In contrast, saccharin-deprived rats demonstrated improved performance in the behavioral paradigms used here.

Animals↗
PubMed2006

Reinforcing properties of ethanol in neonatal rats: involvement of the opioid system.

Toward understanding why infant rats ingest high levels of ethanol without initiation procedures, the authors tested effects of mu and kappa receptor antagonists on ethanol reinforcement in neonatal rats. After an intracisternal injection of CTOP (micro antagonist), nor-Binaltorphimine (kappa antagonist), or saline, newborn (3-hr-old) rats were given conditioning pairings of an odor with intraorally infused ethanol or a surrogate nipple with ethanol administered intraperitoneally (to minimize ethanol's gustatory attributes). In each case, these opioid antagonists reduced or eliminated ethanol's reinforcement effect. The same effects occurred with saccharin as the reinforcer in olfactory conditioning. The results imply that activation of mu and kappa receptors, apparently acting jointly, is necessary for reinforcement or that antagonists of this activity impair basic conditioning.

Analysis of Variance↗
PubMed2005

Cash value of voucher reinforcers in pregnant drug-dependent women.

This study examined the relative reinforcing potency of vouchers and cash in drug-dependent pregnant women (N = 48) across voucher values (US 10 dollars, US 50 dollars, and US 100 dollars) by use of a series of choices to understand how exchange-delay features of voucher reinforcers influence their reinforcing potency compared with cash. The study also examined a no delay vs. 2-day delay of the cash alternative. Generally, cash was selected at 80%-90% of voucher face values. Vouchers were also discounted less when a 2-day delay was imposed on the cash option compared to the immediately available cash. These results suggest that voucher discounting does occur among patients in drug treatment. However, vouchers retain 80%-90% of their cash value and thus remain relatively potent reinforcers.

Adult↗
PubMed2000

Comparison of the reinforcing and anxiogenic effects of intravenous cocaine and cocaethylene.

People report that ethanol improves the experience produced by cocaine. This effect may be attributable to cocaethylene (CE), a cocaine metabolite formed only in the presence of ethanol. To test this, rats were trained to run an alley for a single intravenous dose of either cocaine (0.5-2.0 mg/kg) or an equimolar dose of CE (0.75-2.88 mg/kg). The rats' start latency and running speed measured the reinforcing effects of the drugs and the number of times rats approached but failed to enter the goal box (i.e., approach-avoidance retreats) indexed anxiety. Rats reinforced with CE had shorter start latencies and faster running speeds and exhibited fewer "retreats" than cocaine-reinforced rats. These results suggest that CE is more reinforcing and less anxiogenic than cocaine and hence may account for the combined effects of cocaine and ethanol in humans.

Animals↗
PubMed1979

Comparison of effects of small lesions in posterodorsal septum on spontaneous and rerun correction (contingently reinforced) alternation in rats.

In the first part of the experiment, characteristics of T-maze alternation behavior were compared by giving one group of 11 rats seven sessions under conditions of "rerun correction" (contingent reinforcement for alternation) and another group of 11 rats the same number of sessions with noncontingent reinforcements, i.e., entering either goal arm of the T-maze was reinforced. Both groups alternated significantly above chance, and the difference in medians between groups was small but significant in later sessions. However, rats given rerun correction training quickly came against the "ceiling" of 100% alternation, and individual differences were small. The scores of rats run under conditions of "spontaneous" alternation were more variable, both within and between rats. In the second part of the experiment, six rats in each group received small electrolytic lesions in the posterodorsal septum. There were five operated-control rats from each group. After 2-wk postoperative recovery all rats were again given seven sessions in the T-maze. Under rerun correction procedure (contingent reinforcement), the controls retained near-perfect alternation scores. Most animals with lesions dropped to chance levels but recovered to control level over the seven sessions. Rats tested under spontaneous alternation conditions behaved quite differently. The control group continued to alternate significantly, but rats with lesions significantly alternated less and did not recover.

Animals↗
PubMed1983

Oral methadone self-administration: effects of dose and alternative reinforcers.

We examined the efficacy of oral methadone as a reinforcer by offering methadone maintenance patients the chance to self-administer extra doses of methadone occasionally in addition to their regular dose. Seven maintenance patients received twice-weekly choices between methadone doses or money. Doses were 0, 1, 5, 10, 25, or 50 mg methadone; the alternative money option was $1 or $5. Extra methadone doses were reliably self-administered by maintenance patients, and percent of dose choices rose as the size of the dose offered increased. Thus extra methadone doses functioned as reinforcers in this situation. Further, across the entire dose range, more dose choices were selected when $1 was offered than when $5 was offered as an alternative. Thus methadone self-administration was influenced by the alternative reinforcers available for drug refusal. Neither reports of subjective withdrawal symptoms nor reduction of symptoms after extra methadone predicted methadone self-administration, but dose selections were more likely when urinalysis results indicated recent illicit opiate use. The reinforcing effects of oral methadone in methadone-tolerant patients may be an important factor in the popularity of this treatment among drug abusers and in the long-term treatment retention generally observed during methadone maintenance.

Adult↗
PubMed2005

Comparison of the reinforcing effects of cocaine and cocaine/heroin combinations under progressive ratio and choice schedules in rats.

The co-use of cocaine and heroin is relatively common, with a growing clinical and preclinical literature dedicated to investigating the factors underlying the phenomenon. Specifically, several studies have compared the reinforcing effects of the coadministration of cocaine and heroin, referred to commonly as 'speedball', to either drug alone. The present study assessed whether addition of heroin to a wide range of cocaine doses produces reinforcing effects greater than cocaine alone using both a progressive ratio (PR) schedule and a choice procedure. Patterns of coadministration of cocaine and heroin offered simultaneously were also assessed using double-lumen cannulas. Under the PR schedule, speedball combinations across a range of doses (0.38-3.0 mg/kg/inf cocaine+1.5-48 microg/kg/inf heroin) did not support higher break points than cocaine alone. When cocaine and heroin were made available concurrently (ie on two separate levers), rats self-administered cocaine exclusively. Using a choice procedure, however, a preference was demonstrated for some speedball combinations (eg 0.18 mg/kg/inf cocaine+50 microg/kg/inf heroin; 0.38 mg/kg/inf cocaine+50 microg/kg/inf heroin) over cocaine alone (0.75 mg/kg/inf). So while results obtained using the PR schedule do not support the hypothesis that speedball combinations are more reinforcing than cocaine alone, data from the choice procedure do support this hypothesis. These apparently discrepant results demonstrate that these models are measuring different aspects of drug reinforcement, and suggest that choice procedures in rats provide a useful tool to study speedball self-administration.

Animals↗
PubMed1998

Pharmacological stimuli decreasing nucleus accumbens dopamine can act as positive reinforcers but have a low addictive potential.

Opioid peptides, through mu and delta receptors, play an important part in reward. In contrast, the role of kappa receptors is more controversial. We examined the possible positive reinforcing effects of a selective kappa agonist, RU 51599, by studying intravenous self-administration in the rat. The effect of RU 51599 on dopamine release in the nucleus accumbens was also studied, as opioids and dopamine seem to interact in the mediation of reward. The behavioural and dopaminergic effects of RU 51599 were compared with those of the mu agonist heroin. Rats self-administered both RU 51599 (6.5, 20 and 60 microg/inj) and heroin (30 microg/inj) at low ratio requirement. When the ratio requirement, i.e. the number of responses necessary to receive one drug infusion, was increased, self-administration of RU 51599 rapidly extinguished, whereas self-administration of heroin was maintained. Intravenous infusion of RU 51599 (100, 200 and 400 microg) dose-dependently decreased (25, 30 and 40%, respectively) extracellular concentrations of dopamine, as measured by means of microdialysis in freely moving rats. In contrast, heroin increased accumbens dopamine (130% over baseline). These results indicate that kappa receptors, similarly to mu ones, can mediate positive reinforcing effects of opioid peptides. However, the strength of the reinforcement is very low for kappa receptors. This suggests that changes in accumbens dopamine do not correlate with the capacity of a stimulus to induce reward or aversion. In contrast, a parallel seems to exist between an increase in accumbens dopamine and the drive to reach or obtain a positive reinforcer.

Animals↗
PubMed1993

Corticosterone in the range of stress-induced levels possesses reinforcing properties: implications for sensation-seeking behaviors.

In both humans and animals certain individuals seek stimuli or situations that are considered stressful and consequently avoided by others. A common feature of such situations is an activation of the hypothalamo-pituitary-adrenal axis leading to secretion of glucocorticoids. Since glucocorticoids have euphoric effects in some individuals and have been shown to potentiate the reinforcing properties of drugs of abuse in animals, we hypothesized that corticosterone secretion during stress-like situations may have reinforcing effects and that a higher sensitivity to the reinforcing effects of glucocorticoids might be a biological basis of sensation seeking. In this report we show that (i) corticosterone has reinforcing properties, as evidenced by the development of intravenous self-administration, (ii) self-administration of corticosterone is observed at plasma levels that are comparable to those induced by stress, and (iii) there are individual differences in corticosterone self-administration, which are related to individual reactivity to novelty and sensitivity to drugs of abuse, behavioral features akin to certain traits of high-sensation seekers. These findings provide insight into the physiological role of glucocorticoids and the biology of sensation seeking and may have clinical implications.

Analysis of Variance↗
PubMed1992

Parental values, reinforcement, and young children's prosocial behavior: a longitudinal study.

In this study, the authors assessed the relation of parental reinforcement and parental values to young children's prosocial behaviors. Parents' dyadic interactions with their 1- to 2-year-old children were videotaped in the home on two occasions approximately 6 months apart. The children also were videotaped playing with a peer at 3 1/2 to 4 1/2 years of age. Parental reinforcement of the children's prosocial behaviors was coded, as were the children's prosocial behaviors with the peer. The frequency of girls' spontaneous prosocial behaviors decreased in the early years; modest consistency was observed for boys (but not girls) across the two parental sessions. No relation existed between the frequency of children's prosocial behaviors with their parents and their behaviors with peers. Both maternal and paternal valuing of compliance were negatively related to the mothers' use of reinforcement for children's spontaneous prosocial behaviors. Parental reinforcement of compliant prosocial behaviors was negatively related to children's compliance with a peer's request for prosocial behavior and positively related to defensive behavior with the peer. Fathers' valuing of prosocial behavior was associated with children's compliance with the peer's requests for prosocial action. Parents who valued compliance had children who exhibited low levels of compliant prosocial behaviors with the peer, possibly because of the depressed level of peer interaction.

Child, Preschool↗
PubMed1975

Modification through modeling and reinforcement in leaderless groups.

This study compared the effects of modeling plus reinforcement (MR), reinforcement alone (R), and demand characteristics (D) on individual verbal output in a leaderless group discussion. Seventy-two male and female volunteers from undergraduate psychology courses (mean age 20.7 years) were assigned to three-person groups in the three conditions and participated in two 10 minute discussions. Ss who spoke the least in the first discussion were chosen as target persons (TPs). TPs in the R condition were reinforced for talking and punished for silence. TPs in the MR condition received the same treatment but were also exposed to a leadership modeling film. TPs in the D condition received no reinforcement, but were encouraged to become the group's leader. All conditions showed increases in verbral output, but the MR was superior to both the R (p less than .05) and D (p less than .01) conditions. The results were interpreted as consistent with Bandura's mediational theory of modeling.

Adult↗
PubMed1984

Learned helplessness: effects of noncontingent reinforcement and response cost with emotionally disturbed children.

In order to investigate the effectiveness of noncontingent reinforcement and response cost in inducing learned helplessness and to determine whether depressed Ss respond differently than nondepressed Ss, 28 emotionally disturbed children (20 boys, 8 girls) were tested in a modified learned helplessness paradigm. Children's Depression Inventory score and diagnosis were each used to distinguish "depressed" and "nondepressed" children. Half of the depressed group and half of the nondepressed group received noncontingent response cost, the other half of the two groups received noncontingent positive reinforcement. Results indicated that both noncontingent response cost and noncontingent reinforcement led to reduced persistence time relative to persistence under conditions of contingent reinforcement. There was only one significant difference between depressed and nondepressed Ss (differential persistence time over trials) and there were no significant interactions. Results were discussed in terms of Seligman's formulation of learned helplessness and the extension of this model to a clinical child population.

Achievement↗
PubMed1989

The effects of self-monitoring and reinforcement on exercise adherence.

Two behavioral techniques were assessed to determine their effects on subjects' adherence to unsupervised exercise. The subjects were 35 moderately fit persons who had just completed an adult fitness program (AF group) and 42 sedentary individuals who were recruited through the campus newspaper (NEWS group). Participants were randomly assigned to one of three conditions: (a) self-monitoring, (b) reinforcement supplied by another person, or (c) control. All subjects were given instructions on how to exercise and asked to exercise on their own for 18 weeks. Self-monitoring subjects kept written records of their exercise behavior, while reinforcement subjects verbally reported their exercise behavior to another person who periodically administered rewards. Pre- and posttreatment tests on the NEWS group revealed no significant treatment or interaction effects. However, the reinforcement group had an 11% improvement in predicted max VO2 and a 9 bpm improvement in exercise heart rate compared to 7.8%, 5 bpm for the self-monitoring (SM) group and 5.3%, 6 bpm for the control group. T-tests indicated that reward and SM groups improved significantly on these variables, whereas the control group did not. SM (M = 2.07) and reinforcement (M = 2.29) groups reported a significantly higher frequency of exercise per week than the control (M = 1.36) group. The AF subjects were able to maintain their fitness level (with the exception of a small increase in body fat) over the 18-week period. The behavioral interventions had little differential effect on adherence by AF subjects who were already regular exercisers.

Adult↗
PubMed2001

Improving attitudes regarding the elderly population: the effects of information and reinforcement for change.

PURPOSE: Altering negative attitudes associated with ageism may be possible by giving people accurate information about older people in conjunction with reinforcement for change. DESIGN AND METHODS: Ninety-nine college students (35 men, 63 women; mean age = 20 years, SD = 2.78) participated in one of three groups: information only, information plus an innocuous discussion group, and information plus a reinforcement-to-change discussion group. The participants' attitudes toward elderly people were measured before, immediately after the intervention, and at a one-month follow-up. Changes in attitudes across groups and time were analyzed using analysis of variance (ANOVA) and t tests. RESULTS: Information alone produced initial improvements in attitudes in all groups; however, only the group members who received additional reinforcement for change maintained positive attitude changes at one-month follow-up. IMPLICATIONS: This study supports the premise that negative attitudes toward older people are amendable; however, the new attitude may be lost without reinforcement for change.

Adult↗
PubMed2001

Alcohol reinforcement and voluntary ethanol consumption.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The organizer/chair was Ting-Kai Li and the co-chair was Rainer Spanagel. The presentations were (1) Genetic differences in alcohol drinking and reinforcement: The sP and sNP Rats, by Giancarlo Colombo; (2) Ventral tegmental area-Neuroanatomical substrate for alcohol reinforcement, by William J. McBride; (3) Metabolic mapping of alcohol reinforcement, by Linda J. Porrino; (4) Role of opioid receptors in the ethanol-induced place preference in rats exposed to conditioned fear stress, by Tsutomu Suzuki; and (5) Repeated deprivations enhance the reinforcing properties of ethanol in alcohol preferring (P) rats, by Zachary A. Rodd-Henricks.

Alcohol Drinking↗
PubMed1998

Evidence for anatomical specificity for the reinforcing effects of SP in the nucleus basalis magnocellularis.

Previous studies have shown that substance P (SP) exerts reinforcing effects following injection into the region of the nucleus basalis magnocellularis (NBM) in rats. The aim of the present study was to further characterize this effect by examining its anatomical specificity. Reinforcing effects of SP were assessed following unilateral microinjection into the NBM or into the nearby rostral part of the ventral pallidum (VP), using conditioned place preference as an index for reinforcement. Intracranial injection of SP was performed through small diameter glass micropipettes which allowed precise delivery of SP in minute quantities. A single microinjection of SP (0.2 and 1 ng) into the NBM produced a conditioned place preference, whereas injection of SP into the rostral VP failed to alter the preference behavior. The results confirm that SP has reinforcing effects when administered into the NBM and provide evidence that these effects are brain-site specific.

Animals↗
PubMed2000

Reinforcing effects of methamphetamine in planarians.

Reinforcing properties of dopamine agonist, methamphetamine, for planarians were examined with the conditioned place preference (CPP) procedure. The planarians showed preference for the environment associated with methamphetamine administration. This reinforcing effect was antagonized by pretreatment with non-selective dopamine antagonist, haloperidol. Both selective D1 antagonist SCH23390 and selective D2 antagonist sulpiride also blocked the reinforcing effect of methamphetamine. These results suggest that reinforcing effects of dopaminergic drugs can be traced back to invertebrates such as planarians.

Amphetamine-Related Disorders↗