SEARCH · PubMed Health

Results for “Reinforcement Schedule”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources

PubMed2005

Earning and obtaining reinforcers under concurrent interval scheduling.

Contingencies of reinforcement specify how reinforcers are earned and how they are obtained. Ratio contingencies specify the number of responses that earn a reinforcer, and the response satisfying the ratio requirement obtains the earned reinforcer. Simple interval schedules specify that a certain time earns a reinforcer, which is obtained by the first response after the interval. The earning of reinforcers has been overlooked, perhaps because simple schedules confound the rates of earning reinforcers with the rates of obtaining reinforcers. In concurrent variable-interval schedules, however, spending time at one alternative earns reinforcers not only at that alternative, but at the other alternative as well. Reinforcers earned for delivery at the other alternative are obtained after changing over. Thus the rates of earning reinforcers are not confounded with the rate of obtaining reinforcers, but the rates of earning reinforcers are the same at both alternatives, which masks their possibly differing effects on preference. Two experiments examined the separate effects of earning reinforcers and of obtaining reinforcers on preference by using concurrent interval schedules composed of two pairs of stay and switch schedules (MacDonall, 2000). In both experiments, the generalized matching law, which is based on rates of obtaining reinforcers, described responding only when rates of earning reinforcers were the same at each alternative. An equation that included both the ratio of the rates of obtaining reinforcers and the ratio of the rates of earning reinforcers described the results from all conditions from each experiment.

Animals↗

PubMed1964

SELECTIVE PUNISHMENT OF FIXED-RATIO PERFORMANCE.

Key-pecking of pigeons, maintained by an FR 50 grain reinforcement schedule, was punished by shocking the first, middle, or last response of the ratio. Under high shock levels, the three punishment conditions produced differential effects on the behavior. Punishment of the first response of the ratio resulted in consistent and extended post-reinforcement pausing and frequent extended breaks after the initial response(s) of the ratio. Punishment of the 25th response disrupted responding in the first half of the ratio with little effect on the last half of the ratio. Punishment of the final response resulted in breaks and local rate changes in various parts of the ratio. Durations of pauses after reinforcement were more variable when the 25th and 50th responses were punished relative to those when the first response was punished.

Animals↗

PubMed1960

Rewarding properties of intracranial stimulation.

Monkeys can be trained to press a lever to obtain intracranial brain stimulation on a large fixed-ratio schedule as well as on a continuous reinforcement schedule. A long extinction curve appears to be indicative of a future high fixed-ratio performance.

Brain↗

PubMed1992

Stimulus control of behavioral history.

Pigeons were exposed to two different reinforcement schedules under different stimulus conditions in each of two daily sessions separated by 6 hr (Experiments 1 and 2) or in a single session (Experiment 3). Following this, either a fixed-interval (Experiment 1) or a variable-interval schedule (Experiments 2 and 3) was effected in both stimulus conditions. In the first two experiments, exposure to fixed-ratio or differential-reinforcement-of-low-rate schedules led to response-rate, but not pattern, differences in subsequent performance on fixed- or variable-interval schedules that persisted for up to 60 sessions. The effects of reinforcement-schedule history on fixed-interval schedule performance generally were more persistent. In Experiment 3, a history of high and low response rates in different components of a multiple schedule resulted in subsequent response-rate differences under identical variable-interval schedules. Higher response rates initially occurred in the component previously correlated with high response rates. For 3 of 4 subjects, the differences persisted for 20 or more sessions. Previous demonstrations of behavioral history effects have been confined largely to between-subject comparisons. By contrast, the present results demonstrate strong behavioral effects of schedule histories under stimulus control within individual subjects.

Animals↗

PubMed1996

The effects of eticlopride and naltrexone on responding maintained by food, cocaine, heroin and cocaine/heroin combinations in rats.

In the first experiment, responding was maintained for food under a fixed ratio (FR) 10 with a 6-min timeout reinforcement schedule. Eticlopride (0.1-1.0 mg/kg i.p.) dose-dependently decreased the number of food pellets obtained, whereas naltrexone (3-30 mg/kg i.p.) did not significantly alter responding. In the second experiment, intravenous self-administration of cocaine (vehicle, 125, 250 and 500 micrograms/infusion), heroin (vehicle, 5.4, 9 and 18 micrograms/infusion) and cocaine/heroin combinations were maintained under a FR10 reinforcement schedule. Cocaine/heroin combinations included the aforementioned cocaine doses combined with 5.4 micrograms/infusion heroin (CH5.4) or 18 micrograms/infusion heroin (CH18). Cocaine/heroin combinations dose-dependently decreased the number of infusions compared with cocaine alone. Eticlopride (0.03-0.3 mg/kg i.p.) decreased self-administration of 125 micrograms/infusion cocaine and increased self-administration of 500 micrograms/infusion cocaine. Self-administration of 250 micrograms/infusion cocaine was increased after 0.03 and 0.1 mg/kg and decreased after 0.3 mg/kg eticlopride. Eticlopride decreased heroin self-administration, an effect which may be attributable to its rate-decreasing effects. Eticlopride partially reversed the downward shift of the CH5.4 group but did not reverse the effect in the CH18 group. Naltrexone (1.0-10.0 mg/kg i.p.) decreased self-administration of 5.4 micrograms/infusion heroin and increased self-administration of 18 micrograms/infusion heroin. Self-administration of 9 micrograms/infusion heroin was increased by 1.0 mg/kg, not affected by 3.0 mg/kg and decreased by 10.0 mg/kg naltrexone. For the CH5.4 and CH18 groups, naltrexone dose-dependently shifted the dose-effect curves toward the cocaine dose-effect curve. Therefore, self-administration of cocaine/heroine combinations can be maintained in the rat and downward shifts in the cocaine dose-effect curve after combination with heroin are mediated through a naltrexone-sensitive mechanism.

Analysis of Variance↗

PubMed2005

Differences in corticosterone level due to inter-food interval length: implications for schedule-induced polydipsia.

The purpose of this study was to determine the effects of different food-reinforcement schedules on plasma corticosterone (CORT), and its possible involvement in the acquisition and maintenance of schedule-induced polydipsia (SIP). In Experiment 1, three groups of rats were submitted to two different fixed-interval (FI) schedules with inter-food intervals of 30 and 120 s, and to a massed-feeding presentation for 40 days until SIP was well stabilized. In Experiment 2, six groups of rats were exposed to the same schedules, FI 30s and FI 120s, and to the massed-feeding condition, but no water bottles were presented. CORT levels were determined on Days 3 and 40. Results of Experiment 1 indicated that FI 30s schedule, but not FI 120s or the massed-feeding condition, induces excessive drinking from Day 3. Results in Experiment 2 indicated that CORT levels were similar for all the groups on Day 3. However, only animals on the FI 30s schedule did increase their CORT levels on Day 40, with no variation in the hormone in the other two conditions, FI 120s and massed-feeding presentations. The data are discussed in terms of the implications of these results for hypotheses of SIP as anxiolitic behavior.

Animals↗

PubMed2006

SuperState: a computer program for the control of operant behavioral experimentation.

Operant behavioral researches require precise control of experimental devices for delivering stimuli and monitoring behavioral responses. The author developed a software solution named SuperState for controlling hardware devices and running reinforcement schedules. The Microsoft Windows compatible software was written by use of an object-oriented programming language Borland Delphi 5.0, which has simplified the programming of the application. SuperState is a stand-alone easy-to-use green software, without the need for the experimenter to master any scripting languages. It features: (1) control of multiple operant cages running independent reinforcement schedules; (2) enough cage devices (16 digital inputs and 16 digital outputs for each cage) suitable for the need of most operant behavioral equipments; (3) control of most standard ISA-type digital interface cards including Med-Associates Super-port cards and a PCI-type card AC6412, and highly expandable to support other PCI-type interface cards; (4) high-resolution device control (1ms); (5) a built-in real-time cumulative recorder; (6) extensive data analyzing including event recorder, cumulative recorder, block analyzing; the summarized results can be transferred easily to Microsoft Excel spreadsheets through the Clipboard.

Animals↗

PubMed1988

Assessment of pimozide's motor and hedonic effects on operant behavior in rats.

The present study examined the effects of the neuroleptic pimozide on several measures of motor capacity and reinforcement efficacy in rats trained to respond according to a multiple random interval (RI) food reinforcement schedule (mean interreinforcement intervals of 10, 20, 40, 80, and 160 sec). Pimozide (0.125, 0.25, 0.5, and 1.0 mg/kg) produced a dose-dependent suppression of response rates for all five RI schedules and a dose-dependent increase in response duration. An independent measure of motor activity in photocell activity chambers also was decreased by pimozide in a dose-dependent manner. Photocell activity was significantly correlated with response duration and with the Matching Equation parameter k. Thus, all three measures of motor performance revealed similar decreases in motor capacity at the high dose of pimozide. Reinforcement efficacy also was reduced by the 1.0 mg/kg dose of pimozide as indicated by an increase in the Matching Equation parameter Re. The parameters k and Re were not significantly correlated, suggesting that these two Matching Equation parameters do provide independent measures of motor capacity and reinforcement efficacy, respectively. The present results demonstrate the importance of obtaining measures other than simple response rates in order to assess drug effects on operant behavior.

Analysis of Variance↗

PubMed1970

Instrumental conditioning of the rat cardiac control systems.

The PR, PP, and RR intervals of the rat EKG were instrumentally conditioned using a variety of reinforcement schedules under computer control. The PR and PP intervals could be conditioned independently. Individual rats demonstrated either a steady shift of their response distribution or an abrupt change of an all-or-none variety. Some response distributions shifted continuously; others, through the growth of new response patterns in a manner reminiscent of hypothesis-testing behavior of human subjects. A study of the effects of single reinforcements showed that each reinforcement contributed to the learning behavior of the subject, in a well-defined but nonlinear fashion.

Animals↗

PubMed2002

Aggressive behavior as a reinforcer in mice: activation by allopregnanolone.

RATIONALE: The neurobiological mechanisms that underlie the motivation to engage in an aggressive confrontation remain to be investigated. OBJECTIVE: The objective was to develop a method to differentiate pharmacologically the performance elements of aggressive behavior from behaviors that precede an aggressive encounter. METHODS AND RESULTS: Male CFW mice were housed as "residents" and trained to poke their nose in a hole in a panel placed into the home cage. After fulfilling a specific response requirement, an "intruder" male mouse was introduced for a brief aggressive encounter. In experiment I, the mice were maintained on a fixed ratio schedule of ten responses (FR10) and after stable responding, extinction and stimulus control were assessed by switching the active hole in an ABA design. In experiment II and III, the mice were maintained on a fixed interval schedule of 10 min (FI10 min) and responded with accelerating rates towards the end of the interval (mean index of curvature was 0.37). In experiment III, the mice were given the GABA(A) receptor positive modulator allopregnanolone (5.6-17 mg/kg or vehicle, IP), before responding on an FI10 min schedule reinforced by a 5-min aggressive encounter. Allopregnanolone had bitonic effects on FI responding and aggressive behavior. The low dose of allopregnanolone nearly doubled overall response rate without affecting the index of curvature, attack bites or sideways threats. The moderate dose increased attack behaviors by about 45% and had little effect on response rate and the index of curvature. In contrast, the higher dose decreased the index of curvature but had no effect on aggressive behavior or overall response rate. CONCLUSIONS: These data support previous demonstrations that certain GABA(A) positive modulators heighten aggressive behavior. Moreover, examining operant responding that is reinforced by the opportunity for aggression, it may be possible to dissociate pharmacological effects on the behaviors leading up to an aggressive encounter from their effects on specific aggressive acts.

Aggression↗

PubMed2005

Toward an objective characterization of an anhedonic phenotype: a signal-detection approach.

BACKGROUND: Difficulties in defining and characterizing phenotypes has hindered progress in psychiatric genetics and clinical neuroscience. Decreased approach-related behavior and anhedonia (lack of responsiveness to pleasure) are considered cardinal features of depression, but few studies have used laboratory-based measures to objectively characterize these constructs. METHODS: To assess hedonic capacity in relation to depressive, particularly anhedonic, symptoms, 62 participants completed a signal-detection task based on a differential reinforcement schedule. Anhedonia was operationalized as decreased reward responsiveness. RESULTS: Unequal frequency of reward between two correct responses produced a response bias (i.e., a systematic preference to identify the stimulus paired with the more frequent reward). Subjects with elevated depressive symptoms (Beck Depression Inventory scores >/= 16) failed to show a response bias. Impaired reward responsiveness predicted higher anhedonic symptoms 1 month later, after controlling for general negative affectivity. CONCLUSIONS: Impaired tendency to modulate behavior as a function of prior reinforcement might underline diminished hedonic capacity in depression. When applied to a clinical population, objective assessments of participants' propensity to modulate behavior as a function of reward might provide a powerful tool for improving the phenotypic definition of depression and thus offer a reliable behavioral screening approach for neuroscience studies of depression.

Adolescent↗

PubMed2004

Intrinsic signal recording from a monkey whose behavior was maintained by a schedule of reinforcement.

Optical recording of cortical activity in awake monkeys has enhanced our understanding of the functional anatomy of the primary visual cortex (V1). However, cortical representation of visual cognition has not been studied by optical recording, even though the greatest merit of using awake animals is that they can offer advantages in studying cognitive function that anesthetized animals cannot. Thus far, the optical recording method has not been combined with tasks that accompany body movements because of concern about movement noise, although behavioral tasks are helpful in the study of animal cognition. Here, I tested the influence of body movements during the signal acquisition period on the resultant images. I recorded the intrinsic signals associating with different orientations from V1 of a monkey who was emitting behavior during the signal acquisition period. Although the monkey's behavior was maintained on a variable-interval schedule that typically induces a high rate of response, orientation maps were consistently obtained. Therefore, a successful recording under this operant regimen implies the applicability of the optical recording method to other behavioral tasks. Several constraints in applying optical recording to studies using behaving animals are also discussed.

Analysis of Variance↗

PubMed1998

The relationship between intravenous cocaine self-administration and avidity for saccharin.

Two experiments were conducted to determine whether measures of saccharin intake could be used as a predictor of intravenous cocaine self-administration. Saccharin avidity, defined as the ratio of total daily fluid intake when saccharin and water were available to total intake when only water was available, was measured in male rats. Cocaine self-administration (0.4 mg/kg/infusion) was subsequently measured in an initial 18-h session, followed by daily 1-h sessions in which the infusion dose and the reinforcement schedule were varied. In the initial overnight session, some rats obtained the maximum or near-maximum number of infusions; this high level of cocaine intake was unrelated to saccharin avidity. In the remaining rats, there was a pattern somewhat resembling an "inverted-U," in which rats with low or high avidity self-administered less cocaine than those with intermediate avidity. This pattern reemerged later in the experiment when rats were tested at a low cocaine infusion dose combined with a FR-6 reinforcement schedule. In a second experiment, no significant relationship was observed between the self-administration of a lower cocaine dose (0.125 mg/kg/infusion) and avidity for either saccharin or the artificial sweetener SC-45647. Although these results are consistent with a previous report indicating no simple relationship between saccharin preference and the acquisition of cocaine self-administration, they do suggest that a more complex relationship may be observed under some conditions. Additional research with other drugs, as well as with caloric and noncaloric sweeteners, will be needed to determine the usefulness of taste measures in identifying or treating substance abuse.

Animals↗

PubMed1985

A parametric description of amphetamine's effect on response rate: changes in reinforcement efficacy and response topography.

A mathematical model was used to describe the effects of amphetamine on the rate of a reinforced response in the rat. The model provides measures of reinforcement efficacy and response topography for behavior maintained by variable-interval reinforcement schedules. In this study the measured behavior was a lever press, the reinforcer was water, and the variable-interval schedules provided five different rates of reinforcement, ranging from about 20 to 660/h. In each session the rats were exposed to each of the five schedules, and as reinforcement rate increased, the rate of lever pressing increased in a negatively accelerated manner that was closely approximated by the equation for a rectangular hyperbola. Amphetamine changed response rate and the parameters of the best-fitting hyperbolas. The 0.25-1.0-mg/kg doses increased response rate, and the parameter changes supported the interpretation that the increases were due primarily to an increase in reinforcement efficacy. The 2.0- and 3.0-mg/kg doses decreased response rates maintained by low reinforcement rates and increased response rates maintained by high reinforcement rates, and the parameter changes supported the interpretation that at higher doses amphetamine produced counteracting changes in reinforcement efficacy and response topography: reinforcement efficacy decreased, whereas response topography changed so as to increase response rates.

Animals↗

PubMed1986

[Rapid establishment of nicotine intravenous self-administration behavior in rats].

The reinforcing effect of nicotine was investigated using the intravenous self-administration method in rats. After forced iv injection of nicotine (3, 10 and 30 micrograms/kg/inj) at 1-hr intervals for 3 days in 3 dose-level groups, self-administration sessions under the continuous reinforcement schedule were carried out for 15 days. Rats initiated self-administration of nicotine rapidly in 10 and 30 micrograms/kg/inj groups. Daily self-administration responses by nicotine (30 micrograms/kg/inj) were 3-10 times the control levels. Total self-administration responses for 15 days increased in a dose dependent manner. When the fixed ratio was increased from 1 to 4 and 8 after the 15 days self-administration session in the nicotine (10 and 30 micrograms/kg/inj) groups, lever press responses increased only about 2 times, and self-administration responses decreased in the both groups. These findings suggest that nicotine becomes a reinforcer rapidly, but the magnitude of reinforcing effect is relatively week after the acquisition of nicotine for a short period.

Animals↗

PubMed1992

Effects of methylphenidate on response rate and measures of motor performance and reinforcement efficacy.

This experiment evaluated the effects of methylphenidate on reinforced responding in rats. In each session the subjects (rats) earned reinforcement on seven different variable-interval reinforcement schedules. The average intervals varied from 108 to 3 s and provided reinforcement rates ranging from about 30 to 1100/h. Response rate was a negatively accelerated function of reinforcement rate. Low doses of methylphenidate (1.0 and 2.0 mg/kg) increased responding maintained by the four leanest schedules, but had little effect on responding maintained by the three densest schedules. In contrast, an 8.0 mg/kg dose increased responding maintained by the three densest schedules and slightly decreased responding maintained by leaner schedules. A quantitative model of reinforced responding, referred to as the matching law or response strength equation, was fitted to the data. This equation has two parameters. On the basis of previous experiments, one was used to measure changes in reinforcement efficacy and the other was used to measure changes in motor performance. The 1.0 and 2.0 mg/kg doses changed the reinforcement parameter in the same way as did increases in deprivation and reward magnitude. The 8.0 mg/kg dose changed the motor parameter in the same was as did decreases in lever weight. It was concluded that methylphenidate increases reinforcement efficacy, and that the highest dose changed the topography of responding. The results are discussed in terms of the response strength equation, the rate dependency principle, and the question of how to interpret changes in reinforcement efficacy and motor performance.

Animals↗

PubMed1992

Etonitazene delivered orally serves as a reinforcer for Lewis but not Fischer 344 rats.

Oral etonitazene self-administration was systematically investigated in two inbred strains of rats, Lewis (LEW) and Fischer 344 (F344). For LEW rats, etonitazene maintained higher rates of lever pressing and was consumed in larger volumes than the water vehicle when the reinforcement schedule was fixed ratio (FR) 8. In contrast, with F344 rats responding did not systematically exceed water values at any etonitazene concentration. LEW rats also drank substantially more etonitazene than F344 rats, and at FR 8 only LEW rats showed the typical inverted U-shaped function between etonitazene concentration and number of responses. For the LEW strain, response rate increased as FR size increased from FR 1 to FR 2 and FR 4, but decreased at FR 8. For the F344 strain, as FR size increased response rate showed small increases, but the response rates were far lower than those of the LEW strain. The results support the conclusion that etonitazene was an effective reinforcer for LEW but not F344 rats. These findings demonstrate genetic differences in opioid reinforcement of operant behavior and indicate that genotype can be an important determinant of whether etonitazene serves as a reinforcer.

Administration, Oral↗

PubMed1992

Reinforcement loss and behavioral tolerance to d-amphetamine: using percentile schedules to control reinforcement density.

Two procedures were used to examine the impact of reinforcement loss on the development of behavioral tolerance to the effects of d-amphetamine on control over response number in rats. Under both procedures, trials consisted of at least one left-lever press followed by a single right-lever press. Consecutive left-lever presses on each trial comprised a "run". A targeted percentile schedule provided reinforcement if the current run length was closer to the target length (12) than two-thirds of the most recent 24 runs. This procedure differentially reinforced runs around 12 while holding reinforcement probability constant at 0.333. A second group acquired the differentiation under the percentile schedule, but was then shifted to a procedure which yoked reinforcement probability by subject and run length to that obtained under asymptotic percentile schedule performance. The two procedures generated roughly comparable, but not identical, control run lengths, response rates, reinforcement probabilities and reinforcement rates. Only under the yoked procedure, however, did drug-induced disruptions in run length produce decreases in reinforcement density. Acute administration of amphetamine produced dose-related decreases in run length and overall response rate under both procedures. Daily pre-session administration of 1.7mg/kg amphetamine persistently suppressed run length under the percentile procedure, but not under the yoked procedure. Run lengths under the latter gradually increased with repeated amphetamine to a level equal to or slightly below baseline levels. Response rate was suppressed initially, and tolerance developed inconsistently to this effect in both groups. Dose-effect curves obtained when doses of amphetamine were substituted for the chronic dose showed a larger shift to the right with the yoked than percentile group for run length, and a similar but smaller effect for overall response rate. These results indicate that reinforcement loss substantially contributes to the development of tolerance to the behavioral effects of amphetamine, even when the comparison behaviors are generated by reinforcement contingencies that under non-drug conditions control very similar rates and patterns of behavior and reinforcement. Future comparison of acute and chronic drug effects on behaviors maintained by the percentile and yoked procedures may prove very helpful in illuminating drug-behavior interactions and the dynamic interrelations typically engendered by more traditional reinforcement schedules.

Journal Article↗