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PubMed2003

Dynamics of the reorganization of an operant food-procuring response during an increase in the delay of reinforcement in monkeys.

Operant activity was studied in monkeys in a situation in which they actively initiated a frequency of pressing a lever to obtain subsequent food reinforcement. Studies addressed the dynamics of relearning when the duration of the lever holding time needed to obtain reinforcement was increased from 1 to 2.5 sec. Studies were performed in three series of experiments with two-month intervals between series. The process whereby the animals solved the food-procuring task when the duration of the operant reaction was increased in conditions of constant sensory stimuli occurred in three stages: 1) emotional reactivity in the form of hyperactivation of operant activity, reflecting a conflict state arising as a result of the dissonance between the completed action and the absence of the expected result; 2) intermediate stabilization, when the outcome of the food-procuring behavior with the reinforcement delay of 2.5 sec coincided with that with the delay of 1 sec; 3) establishment of the desired lever holding time by the time the food reinforcement was presented.

Animals↗

PubMed2004

Choice with initial and terminal link reinforcement: an alternative self-control paradigm.

Self-control is demonstrated when a less desirable immediate outcome is chosen to ensure a substantially better future. In a novel animal analogue of this situation, primary reinforcement was delivered in both the initial and terminal links of a concurrent chain schedule. Rats made initial link choices between equal amounts of ethanol-free or ethanol-containing milk. Choosing the ethanol-free reinforcer resulted in delivery of the larger terminal link reinforcer and was thus analogous to self-control. Self-control decreased as the delay between initial and terminal links increased. The results have implications for human choice situations where decisions are made between two immediately available reinforcement alternatives each associated with a different delayed outcome.

Alcohol Drinking↗

PubMed2004

Effects of medial septal lesions on action-outcome associations in rats under conditions of delayed reinforcement.

In operant tasks, control rats maintain high response rates under positive contingencies, when the probability of reinforcement is greater following a response (contingent reinforcement) than during the absence of that response. However, as contingencies approach zero, response rates decrease. In this experiment, under immediate contingent reinforcement, rats with medial septal lesions reduced their response rates, just like controls, when contingencies were shifted from positive toward zero. However, the septal rats were less sensitive to this contingency shift, compared with controls, when there was a 5-s delay between lever presses and contingent reinforcements. This lesion effect appeared to be due to a failure of voluntary response memory, which impaired sensitivity to operant contingencies when there was a delay between action and outcome.

Animals↗

PubMed2005

Cannabinoid agonists but not inhibitors of endogenous cannabinoid transport or metabolism enhance the reinforcing efficacy of heroin in rats.

Accumulating evidence suggests that the endogenous cannabinoid system is involved in the reinforcing effects of heroin. In rats intravenously self-administering heroin, we investigated effects of cannabinoid CB1 receptor agonists and compounds that block transport or metabolism of the endogenous cannabinoid anandamide. The natural cannnabinoid CB1 receptor agonist delta-9-tetrahydrocannabinol (THC, 0.3-3 mg/kg i.p.) did not alter self-administration of heroin under a fixed-ratio one (FR1) schedule, except at a high 3 mg/kg dose which decreased heroin self-administration. Under a progressive-ratio schedule, however, THC dose-dependently increased the number of 50 mug/kg heroin injections self-administered per session and the maximal ratio completed (break-point), with peak increases at 1 mg/kg THC. In addition, 1 mg/kg THC increased break-points and injections self-administered over a wide range of heroin injection doses (25-100 microg/kg), indicating an increase in heroin's reinforcing efficacy and not its potency. The synthetic cannabinoid CB1 receptor agonist WIN55,212-2 (0.3-3 mg/kg i.p.) had effects similar to THC under the progressive-ratio schedule. In contrast, AM-404 (1-10 mg/kg i.p.), an inhibitor of transport of anandamide, and URB-597 (0.01-0.3 mg/kg i.p.), an inhibitor of the enzyme fatty acid amide hydrolase (FAAH) that degrades anandamide, or their combination, did not increase reinforcing efficacy of heroin at any dose tested. Thus, activation of cannabinoid CB1 receptors facilitates the reinforcing efficacy of heroin and this appears to be mediated by interactions between cannabinoid CB1 receptors and mu-opioid receptors and their signaling pathways, rather than by an opioid-induced release of endogenous cannabinoids.

Animals↗

PubMed2002

Up or down: the influence of upcoming reinforcement on consummatory and operant behavior.

Research has shown that animal subjects that are given a chance to consume a low-valued substance will consume less of it if a high-valued substance will soon be available than they would if the low-valued substance were to remain available (negative consummatory contrast). Research has also shown that subjects that lever press for a low-valued reinforcer will press the lever more often for that reinforcer if they will soon be able to lever press for a high-valued reinforcer than they would if they continue to press for the low-valued reinforcer (positive induction). The present study investigated these different changes in behavior across 3 experiments. The results suggest that the occurrence of contrast or induction does not depend on the type of substances that are used. We argue that further investigation of the contrast vs. induction issue is warranted because it has empirical, theoretical, and applied implications.

Animals↗

PubMed2006

Induction when rats lick for 1% liquid-sucrose reinforcement.

Previous research reported that rats responding for 1% liquid-sucrose reinforcement when 32% sucrose reinforcement is upcoming will decrease their response rate (contrast) if licking is the dependent measure and increase their response rate (induction) if pressing a lever is the dependent measure. The present study investigated whether induction could be observed when licking served as the dependent measure and whether induction in lever pressing and contrast in licking behaviour could be concurrently observed. Experiment 1 found induction when rats licked to earn the rewards but consumed them at a location separate from the spout licked to earn them. Experiment 2 also found induction when rats earned (and consumed) rewards by licking the same spout throughout the session. Experiment 3 separately measured instrumental lever pressing for sucrose rewards and licking the sucrose during the reward period. We found that both measures increased for 1% sucrose when 32% sucrose reinforcement was upcoming. The present results indicate that the type of response is not the sole determinant of whether contrast or induction is observed. Rather, they suggest that other procedural details, such as the location of reinforcer delivery, influence which effect is observed. The results also indicate that associative processes underlie the appearance of induction in responding for 1% sucrose.

Analysis of Variance↗

PubMed2004

Transient reinforcing effects of phenylisopropylamine and indolealkylamine hallucinogens in rhesus monkeys.

Relatively few studies have assessed the reinforcing effects of hallucinogenic compounds, and no such studies have attempted to engender contingent responding for these compounds in animals with behavioral histories that include experience with serotonergically mediated reinforcing effects. The objectives of the present study were to investigate the capacity of several hallucinogenic compounds to maintain self-administration behavior in rhesus monkeys with a previous history of 3,4-methylenedioxymethamphetamine (MDMA) self-administration, and to compare these effects across a range of doses of drugs from two structural classes (indolealkylamines and phenylisopropylamines). The results indicate that no compound generated reliable responding and that no subject ever self-administered 4-iodo-2,5-dimethoxyphenylisopropylamine (DOI) at rates above those engendered by contingent saline. However, 3 out of 4 subjects did respond at rates between 0.75 and 3.0 responses/s in one or more sessions where N,N-dimethyltryptamine (DMT), mescaline or psilocybin were available. During some of these sessions in which self-administration was maintained, animals earned a majority of all available infusions and appeared intoxicated by the end of the session. This pattern of transient self-administration may indicate that these compounds have weak reinforcing effects, or mixed reinforcing and aversive effects.

Amines↗

PubMed1979

Reduction of stereotyped body-rocking using variable time reinforcement: practical and theoretical implications.

The first experiment assessed the effectiveness of two schedules of reinforcement in reducing stereotypy engaged in profoundly retarded patients in ward environments. These schedules were the differential reinforcement of other behaviour (DRO) and variable time reinforcement (VT). This experiment was terminated prematurely because of problems in implementing the DRO contingencies. However, the VT contingency appeared to reduce stereotypy. The second experiment evaluated the VT schedule of reinforcement alone. Significant decreases in amounts of stereotypy from baseline measures were observed in all five profoundly retarded female subjects. It is tentatively concluded that stereotypies in ward and laboratory environments differ in function. This has implications for the treatment of patients who engage in stereotyped behaviour.

Adolescent↗

PubMed1976

Extraversion and reinforcement in verbal operant conditioning.

The present investigation was designed to study the relationship between extraversion and modes of reinforcement in verbal operant conditioning. A 4 X 3 randomized block design was replicated ten times. Eighty graduate and post-graduate male students were individually subjected to the standard Taffel conditioning procedure. When the numbers of conditioned responses produced by introverts and extraverts were compared, it was found that: (1) under negative reinforcement ('bad' and electric shock), with both the female and male experimenters, and under positive reinforcement ('good') with the male experimenter, the introverts' score was the higher of the two; (2) under positive reinforcement ('good') with the female experimenter, the extraverts' score was higher than that of the introverts.

Adult↗

PubMed2002

The reinforcing efficacy of the dopamine reuptake inhibitor 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) as measured by a progressive-ratio schedule and a choice procedure in rhesus monkeys.

The present series of experiments was undertaken to investigate the variables that influence the reinforcing efficacy of psychostimulants. The time of onset for dopamine transporter (DAT) occupancy of the long-acting, high-affinity DAT blocker 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) was measured using an ex vivo binding assay in rodents and was determined to be significantly longer than for cocaine (30 min versus 2 min). To assess the reinforcing efficacy of PTT relative to cocaine, a discrete-trials drug-drug choice procedure (n = 3) and a progressive-ratio (PR) schedule (n = 4) were used in rhesus monkeys. Cocaine (0.003-0.56 mg/kg/injection) and PTT (0.003-0.03 mg/kg/injection) maintained responding greater than saline under the PR schedule. Maximal breaking points were significantly higher for cocaine compared with PTT. A separate group of monkeys prepared with double-lumen catheters was allowed to choose between cocaine (saline and 0.03-0.3 mg/kg/injection) and PTT (saline, and 0.01 and 0.03 mg/kg/injection). Under these conditions, PTT was not preferred over saline. When saline or 0.01 mg/kg/injection PTT was available as alternatives to cocaine, the highest dose of cocaine maintained greater than 80% choice. When 0.03 mg/kg/injection PTT was the alternative to cocaine, cocaine choice declined to approximately 50%, and total cocaine intake was decreased by ~70% at the highest cocaine dose. These results suggest that the reinforcing efficacy of PTT is less than cocaine in nonhuman primates. Data from studies with PTT indicate that slow-onset, long-acting DAT inhibitors can decrease cocaine self-administration while not functioning robustly as reinforcers, and support the further investigation of these drugs as treatment for cocaine addiction.

Animals↗

PubMed1963

TECHNIQUE FOR SUSTAINING BEHAVIOR WITH CONDITIONED REINFORCEMENT.

Pigeons were intermittently reinforced with food for pecking at one key. Concurrent pecking at a second key intermittently produced conditioned reinforcers (the set of stimuli that accompanied food reinforcement, but not the food). Under these conditions, responding on the second key was maintained indefinitely. Rates and patterns of responding on the second key were a function of the schedule of conditioned reinforcement.

Animals↗

PubMed1965

OBSERVABLE CHANGES OF HYPOTHESES UNDER POSITIVE REINFORCEMENT.

In mathematical models of concept learning it has consistently been assumed that positive reinforcement cannot lead to a change of the hypothesis determining the overt response. When hypotheses are experimentally identified and recorded along with positive and negative reinforcements of stimulus-response pairs, it can be shown that hypotheses may change after a positive reinforcement. Positive reinforcement has an information content for subjects that has not yet been adequately recognized in concept formation studies.

Humans↗

PubMed1991

The effect of positive reinforcement on hourly compliance in nasal continuous positive airway pressure users with obstructive sleep apnea.

Previous reports have described compliance with nasal continuous positive airway pressure (nCPAP) for the treatment of obstructive sleep apnea (OSA) only in terms of the number of patients able to use it beyond their initial trial night or those continuing after some home use. Because of a possible difference between the level of compliance (mean number of hours of use per 24 h) needed for symptomatic relief of OSA versus cardiovascular improvement, the level of hourly compliance in chronic nCPAP users may be important. The first part of this study prospectively examines compliance in a stable population of OSA patients already using nCPAP for 6 months to 2 yr. The second part is a prospective randomized, crossover study examining the effect of weekly (three times) then monthly (twice) positive reinforcement on hourly compliance of new nCPAP users for 3 months versus no reinforcement for 3 months. Positive reinforcement consisted of telephone discussions with the patients about the severity or complications of OSA, benefits of nCPAP, and suggestions about minimizing side effects. Using self-assessment scales, each patient reported the perceived level of improvement from the untreated to the treated condition and the prevalence and severity of side effects from the nCPAP therapy. The level of compliance in stable, chronic nCPAP users with OSA was 6.1 +/- 2.2 h/24 h (n = 9). For the new nCPAP users during the nonreinforced period, the mean compliance was 6.0 +/- 2.8 h/24 h; that during the reinforcement period was 6.0 +/- 2.7 h/24 h (NS). There was no significant correlation between perceived improvement in OSA symptoms or between the perceived side effects of nCPAP versus hourly compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1994

Assessing influential dimensions of reinforcers on choice in students with serious emotional disturbance.

We examined how reinforcer rate, quality, delay, and response effort combined to influence the choices of 6 youths with learning and behavior difficulties, and the viability of an assessment methodology derived from matching theory for determining differential responsiveness to those reinforcer and response dimensions. The students were given two concurrent sets of math problems that were equal on two dimensions but competed on two other dimensions (e.g., one set yielded higher rate and lower quality reinforcement than the other). Competing dimensions were counterbalanced across the six conditions of the initial assessment phase, permitting assessment of each dimension on time allocation. The conditions resulting in the most and least time allocated to one problem set alternative relative to the other were then replicated. Time allocated to each of the problems within sets was differentially affected by the reinforcer and/or response dimensions, with allocation patterns varying across students. The results are discussed in the context of implications for the design of treatments and extrapolations from basic research on matching and behavioral economics.

Adolescent↗

PubMed1996

A comparison of reinforcer assessment methods: the utility of verbal and pictorial choice procedures.

We compared three methods of stimulus preference assessment for verbal children and specifically evaluated the utility of a verbal choice procedure for assessing relative reinforcer value. Using a token system, relative preference for five categories of reinforcers, representing 15 different stimuli, was assessed by three methods: a reinforcer survey, a verbal stimulus-choice questionnaire, and a pictorial stimulus-choice procedure. Results showed that the verbal and pictorial stimulus-choice assessments accurately identified high- and low-preference categories for 3 of 4 participants. Survey results alone often rated multiple categories as high preference, were less likely to identify low-preference categories, and were less likely to correspond with the results of a reinforcer assessment.

Attention Deficit Disorder with Hyperactivity↗

PubMed1998

On the effects of noncontingent delivery of differing magnitudes of reinforcement.

We conducted a parametric analysis of response suppression associated with different magnitudes of noncontingent reinforcement (NCR). Participants were 5 adults with severe or profound mental retardation who engaged in a manual response that was reinforced on variable-ratio schedules during baseline. Participants were then exposed to NCR via multielement and reversal designs. The fixed-time schedules were kept constant while the magnitude of the reinforcing stimulus was varied across three levels (low, medium, and high). Results showed that high-magnitude NCR schedules produced large and consistent reductions in response rates, medium-magnitude schedules produced less consistent and smaller reductions, and low-magnitude schedules produced little or no effect on responding. These results suggest that (a) NCR affects responding by altering an establishing operation (i.e., attenuating a deprivation state) rather than through extinction, and (b) magnitude of reinforcement is an important variable in determining the effectiveness of NCR.

Adult↗

PubMed1999

Competition between positive and negative reinforcement in the treatment of escape behavior.

We compared the effects of reinforcing compliance with either positive reinforcement (edible items) or negative reinforcement (a break) on 5 participants' escape-maintained problem behavior. Both procedures were assessed with or without extinction. Results showed that compliance was higher and problem behavior was lower for all participants when compliance produced an edible item rather than a break. Treatment gains were achieved without the use of extinction. Results are discussed regarding the use of positive reinforcement to treat escape behavior.

Adolescent↗

PubMed2001

Fixed-time schedule effects as a function of baseline reinforcement rate.

Using an arbitrary response, we evaluated fixed-time (FT) schedules that were either similar or dissimilar to a baseline (response-dependent) reinforcement schedule and extinction. Results suggested that both FT schedules and extinction resulted in decreased responding. However, FT schedules were more effective in reducing response rates if the FT reinforcer rate was dissimilar to baseline reinforcer rates. Possible reasons for this difference were evaluated with data analysis methods designed to identify adventitious response-reinforcer relations.

Adolescent↗