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 253 records · Page 14Linked to original sources

PubMed1991

Cocaine and food as reinforcers: effects of reinforcer magnitude and response requirement under second-order fixed-ratio and progressive-ratio schedules.

Reinforcer magnitude and fixed-ratio requirement were varied under two second-order schedules. Under one, the first sequence of a fixed number of responses completed after the lapse of a 10-min fixed interval produced reinforcement. Under the second, a second-order progressive-ratio schedule, the fixed number of responses increased after each reinforcement. Either cocaine (0 to 300 micrograms/kg/inj) or food (0 to 5,700 mg/delivery) reinforcers were delivered. Under some conditions, a 2-s illumination of stimulus lights occurred on completion of each ratio sequence. Under the second-order schedule, as cocaine dose or amount of food increased, rates of responding increased; at the highest values, rates of responding decreased. Increases in the ratio requirement from 10 to 170 responses minimally decreased overall response rates. Under the second-order progressive-ratio schedule, increases in dose of cocaine or amount of food increased rates of responding; at the highest amounts of food, rates of responding decreased but response rates at the highest dose of cocaine remained relatively high. The highest ratio requirement that was completed (breaking point) depended on the dose of cocaine but was less dependent on the amount of food. Removing brief-stimulus presentations had a greater effect on completion of ratio requirements with cocaine compared to food.

Animals↗

PubMed1978

Variability of response location on fixed-ratio and fixed-interval schedules of reinforcement.

Variability of response location was studied in monkeys performing in a six-lever chamber. Fixed-ratio schedules, ranging from FR 1 to FR 300, generated a high degree of stereotypy of response location. In contrast, fixed-interval schedules of comparable reinforcement frequencies (0.06 to 4 minutes) generated much greater variability. These results failed to confirm any simple relationship between response variability and intermittence of reinforcement. Rather, variability seems to be determined by the particular characteristics of the reinforcement schedule.

Journal Article↗

PubMed2003

Human causality judgments and response rates on DRL and DRH schedules of reinforcement.

The effect of various relationships between a response (an investment made in the context of a game) and an outcome (a return on the investment) on judgments of the causal effectiveness of the response was examined. In Experiment 1, response rates and causal judgments were higher for a differential-reinforcement-of-high-rate (DRH) schedule relative to a variable-ratio (VR) schedule with the same probability of outcome following a response. Response rates were also higher for a DRH than for a variable-interval schedule matched for reinforcement rate. In Experiment 2, response rates and causal judgments were lower for a differential-reinforcement-of-low-rate schedule relative to a VR schedule with the same probability of outcome following a response. These results corroborate the view that schedules are a determinant of both response rates and causal judgments, and that few current theories of causal judgment explicitly predict this pattern of results.

Adolescent↗

PubMed1974

Temporal control of periodic schedules: signal properties of reinforcement and blackout.

Pigeons were exposed to periodic food-reinforcement schedules in which intervals ended with equal probability in either reinforcement or brief blackout. The effects on the pattern of key pecking of sequential probability of reinforcement, interval duration, and time to reinforcement opportunity were investigated in three experiments. The major results were: (1) at short absolute interval durations, time to reinforcement opportunity determined both postreinforcement and postblackout pause (time to first key peck within an interval); (2) at long intervals, postblackout pause was consistently shorter than postreinforcement pause, even if both events signalled the same time to the next reinforcement opportunity (omission effect); (3) when reinforcement and blackout signalled different times to the next reinforcement opportunity, within the same experiment, there was some evidence for interactions analogous to behavioral contrast.

Journal Article↗

PubMed1963

Two parameters of a temporally defined schedule of negative reinforcement.

Temporal schedules of negative reinforcement were derived in a manner analogous to those for positive reinforcement, and two parametric studies were carried out with two of the three defining variables. With some limiting values of the defining variables, escape schedules result and data obtained at these values were similar to those obtained in escape studies. At other values of the defining variables avoidance behavior was generated.

Avoidance Learning↗

PubMed2006

The neurotensin receptor agonist NT69L suppresses sucrose-reinforced operant behavior in the rat.

NT69L is a neurotensin analog that can be administered peripherally. It blocks amphetamine- and cocaine-induced hyperactivity in rats. It also blocks nicotine-induced locomotor activity and has shown sustained efficacy in a rat model of nicotine-induced sensitization. The present study tested the effect of NT69L on responding for sucrose reinforcement on a continuous reinforcement schedule (CRF) and incrementing (FR1-FR5) discrimination schedule. Male Sprague-Dawley rats, on restricted food intake, were trained to press a lever for sucrose pellets on a CRF and incrementing discrimination schedule of reinforcement. On the following day, the testing session was followed by an extinction session, where lever pressing was not reinforced. Immediately after extinction, a reversal to CRF was implemented to test for relapse. Trained rats were injected with NT69L (1 mg/kg) or saline 30 min before each testing session. Dopamine, tyrosine 3-hydroxylase, and dopamine receptor mRNA levels were determined. NT69L significantly suppressed the lever pressing behavior for sucrose reinforcement on CRF which measures the "hedonic" value of the reward. NT69L also suppressed sucrose self-administration on the incrementing discrimination schedule of reinforcement (FR3-FR5) that is analogous to the motivational incentive. Reversal to CRF was significantly reduced by pretreatment with NT69L. The suppression of sucrose self-administration behavior by pretreatment with NT69L had a pattern similar to that for extinction. The effect of NT69L on dopamine, tyrosine 3-hydroxylase, and dopamine receptor mRNA levels is discussed relative to changes occurring during extinction.

Animals↗

PubMed2003

Bouts of responding from variable-interval reinforcement of lever pressing by rats.

Four rats obtained food pellets by lever pressing. A variable-interval reinforcement schedule assigned reinforcers on average every 2 min during one block of 20 sessions and on average every 8 min during another block. Also, at each variable-interval duration, a block of sessions was conducted with a schedule that imposed a variable-ratio 4 response requirement after each variable interval (i.e., a tandem variable-time variable-ratio 4 schedule). The total rate of lever pressing increased as a function of the rate of reinforcement and as a result of imposing the variable-ratio requirement. Analysis of log survivor plots of interresponse times indicated that lever pressing occurred in bouts that were separated by pauses. Increasing the rate of reinforcement increased total response rate by increasing the rate of initiating bouts and, less reliably, by lengthening bouts. Imposing the variable-ratio component increased response rate mainly by lengthening bouts. This pattern of results is similar to that reported previously with key poking as the response. Also, response rates within bouts were relatively insensitive to either variable.

Animals↗

PubMed2000

DARPP-32 knockout mice exhibit impaired reversal learning in a discriminated operant task.

The current study was conducted to examine the performance of mice with a targeted deletion of the gene for DARPP-32 in a discriminated operant task using food reinforcement. DARPP-32 plays a central role in regulating the efficacy of dopaminergic neurotransmission. Initially, wild-type and DARPP-32 knockout mice were trained to nose-poke for food on a continuous reinforcement schedule. The minimum response requirement was increased every 5 days until the animals were responding on an FR-15 schedule of reinforcement. At the completion of extensive operant training, reversal learning was assessed. Wild-type and DARPP-32 knockout mice exhibited equivalent performance during acquisition of this task, with both groups increasing operant responding as the schedule of reinforcement was raised. However, significant differences in discrimination learning were observed during the reversal phase, with DARPP-32 knockout mice requiring significantly more trials to reach criterion than wild-type controls. These results provide evidence for a functional role of DARPP-32 in the mediation of processes underlying learning and memory.

Animals↗

PubMed1998

Within-session response rate in rats decreases as a function of amount eaten.

In past studies, within-session changes of rat feeding behavior were always treated as functions of time. This study aimed to describe the within-session decreases of operant response as a function of cumulative amount of food intake. Rats (n = 8) were trained to obtain food pellets by lever-press responses. Session lengths were 45 min. The following results were observed: 1) Response rates during a CRF schedule were well described as a linear function of cumulative amount of food pellets eaten; 2) The linear equation was also accurate in describing the response rates during a semi-VI schedule; and 3) Even if schedules of reinforcement were changed within a single session, response rates in each reinforcement schedule were well described as linear functions of cumulative food intake. Thus, response rates decreased proportionally to the increase in cumulative amount of food intake.

Algorithms↗

PubMed1981

Threshold differences for naloxone and naltrexone in the hypothalamus and midbrain using fixed ratio brain self-stimulation in rats.

Rats were implanted with stimulating electrodes aimed either at the medial forebrain bundle-lateral hypothalamus (MFB-LH) or the midbrain-central gray (MID-GG), and were trained to lever-press for brain self-stimulation on a fixed ratio: 15 schedule of reinforcement. The dose-dependent effects of morphine (0.1-3.0 mg/kg), naloxone (0.1-30 mg/kg), and naltrexone (0.1-30 mg/kg) were then determined during 1 h test sessions. Both naloxone and naltrexone decreased the rate of responding in the MFB-LH as well as in the MID-CG. However, decrements in response rates were produced in the MID-CG by both naloxone and naltrexone at one tenth the doses required to produce similar decrements with electrodes in the MFB-LH. Dose-dependent decreases in response rates produced morphine occurred at the same doses in the two electrode sites. At both sites, the decreases in response rates produced by the highest dose of morphine were antagonized completely by a low dose of naloxone (0.1 mg/kg). At an intermediate dose of naloxone (1.0 mg/kg), antagonism occurred in the MFB-LH but not in the MID-CG. At a high dose of naloxone (10 mg/kg), a depression in lever-pressing occurred at both sites in the morphine-treated animal indicating that the depressive action predominated over antagonism. These data explain the lack of consistency of the effects of naloxone on brain self-stimulation previously reported by different laboratories, and demonstrate that the use of partial reinforcement schedules in a rational approach to the evaluation of opioid effects on brain self-stimulation behavior.

Animals↗

PubMed1975

Hypothalamic self-stimulation in rats following immunosympathectomy or central nerve growth factor antiserum injection.

In Experiment 1, immunosympathectomized rats self-stimulated at a much lower rate on high variable ratio schedules of reinforcement than injected controls. No differences were found for responding on continuous reinforcement or low variable ratio reinforcement schedules. In Experiment 2, a similar reduction in varialbe ratio response rate was found for subjects centrally injected with nerve growth factor-antiserum relative to controls. The results suggest a reduction in central catecholamine levels as a result of antiserum treatment.

Animals↗

PubMed2004

The conditions for temporal tracking under interval schedules of reinforcement.

On many cyclic-interval schedules, animals adjust their postreinforcement pause to follow the interval duration (temporal tracking). Six pigeons were trained on a series of square-wave (2-valued) interval schedules (e.g., 12 fixed-interval [FI] 60, 4 FI 180). Experiment 1 showed that pigeons track square-wave schedules, except those with a single long interval per cycle. Experiments 2 and 3 established that tracking and nontracking are learned and both can transfer from one cyclic schedule to another. Experiment 4 demonstrated that pigeons track a schedule with a single short interval per cycle, suggesting that a dual process--cuing and tracking--is necessary to explain behavior on these schedules. These findings suggest a potential explanation for earlier results that reported a failure to track square-wave schedules.

Animals↗

PubMed1975

Control of the rat's sniffing behavior by response-independent and dependent schedules of reinforcing brain stimulation.

The rat's sniffing response occurs in continuous bursts, at approximately 5-11 Hz. In the present experiments, the analog signal from a thermo-couple probe in the nasal cavity was digitized to provide a discrete logic pulse, defining a sniff, and permitting on-line presentations of reinforcing brain stimulation contingent on momentary sniffing patterns. Schedules of reinforcer presentation included response-independent fixed interval (temporal conditioning), continuous reinforcement (CRF), and differential reinforcement of low rates (DRL 10 sec). Under temporal conditioning, bursts of sniffing were observed immediately after stimulation, and an acceleration in sniffing developed preceding stimulation. Under CFR, operant rate-intensity functions were found to be similar to traditional bar-press data. Under DRL, sniffs were effectively paced by the criterion interval, and interresponse time analyses revealed evidence of temporal discrimination. The behavioral patterns were interpreted in terms of the interplay of operant and respondent functions.

Animals↗

PubMed1992

Parametric manipulations and fixed-interval self-stimulation.

Three experiments investigated hypothalamic self-stimulation under a fixed-interval (FI) reinforcement schedule. An FI 20-s schedule was chosen to reduce stimulation density in order to minimize the influence of priming effects or stimulation aftereffects that can affect responding under other schedules of reinforcement. The first experiment showed that the influence of train duration is greatest at levels up to 1 s and thereafter level off over a wide range of train durations (1-32 s). The second experiment showed that altering frequency, current, or pulse width produced almost identical changes in FI responding. These findings show that the neutral network subserving hypothalamic self-stimulation simply integrates the amount of charge over time. It is relatively insensitive to the combination of stimulation parameters that make up a given waveform. In the third experiment, the chronaxies from the strength-duration curves indicate the neural substrate supporting self-stimulation has a great current-integrating capacity. Together, these experiments show that varying the amount of brain stimulation produce large and consistent changes in a number of FI response measures. These measures effectively describe different attributes of FI performance and include response rate, the postreinforcement pause, interresponse times of short duration and the temporal distribution of responses within the interval.

Animals↗

PubMed1993

Heroin self-administration in rats under a progressive ratio schedule of reinforcement.

Heroin self-administration behavior under a progressive ratio (PR) schedule of reinforcement was evaluated in rats. The schedule was designed to restrict drug intake, minimize opiate dependency, and quantify the number of responses emitted (final response ratio) in order to receive a limited number of heroin infusions. Final ratios were found to be stable and did not increase with chronic (31 days) PR reinforcement. The ability of the PR schedule to detect changes in heroin reinforcement was demonstrated by evaluating the effect of naltrexone pretreatment and unit dose alteration on final ratios. Naltrexone (0.4 mg/kg) reduced final ratios and an inverted U dose-response relationship was established for the unit heroin doses 12.5-100 micrograms/injection. Maximal final ratios occurred with 50 micrograms/injection heroin reinforcement. This PR schedule may provide a useful method for evaluating the effects of pharmacological manipulations or lesions on opiate reinforcement.

Animals↗

PubMed1991

Septal lesions lower responding under fixed-ratio schedules of reinforcement.

Albino Sprague-Dawley rats with complete septal lesions and rats with control operations were studied under fixed-ratio (FR) schedules of reinforcement. Both groups were trained for 10 sessions each under FR 10, 20, 40, 60, 80, and 100. In contrast to findings from progressive FR studies and some simple FR studies, septal lesions resulted in lower overall and local response rates along with longer postreinforcement pauses. These effects were especially evident during the FR 100 schedule of reinforcement. A comparison of reinforcement rate as a function of FR size within the context of behavioral economics (i.e., a demand function) indicated that septal lesions did not alter the reward value of food. These findings suggest that responding on FR schedules of reinforcement can be altered by the various procedures used to train rats to reach the terminal value of a reinforcement schedule.

Analysis of Variance↗

PubMed1989

Discriminative stimulus effects of nicotine in rats trained under different schedules of reinforcement.

There have been few comparisons between different schedules of reinforcement for establishing drugs as discriminative stimuli. Fixed-ratio (FR) 10 and tandem variable-interval 1-min FR-10 schedules have been compared directly in a conventional, nicotine-saline discrimination paradigm with food reinforcement in rats. The discrimination was acquired rapidly under both schedules, with stimulus control by nicotine (0.1 mg/kg SC) being very slightly superior under the FR schedule. In 5-min extinction tests with nicotine, rats maintained under the FR schedule yielded a clear dose-response curve with a bar-selection (quantal) index; in these rats, discrimination of nicotine appeared generally poor, and dose-response curves were shallow, when the percentage of drug-appropriate responding (quantitative index) was calculated. In contrast, rats under the tandem schedule yielded clear dose-response data with both indices. In tests with (+)-amphetamine full generalization was obtained with both schedules, and with both quantitative and quantal indices. Tests of generalization to morphine were negative regardless of the training schedule or index employed. In rats under the FR-10 schedule, overall response rates declined both within and across extinction tests; the relatively high rates of responding maintained by the tandem schedule were more sensitive to the response rate-decreasing effects of morphine and amphetamine. The results confirm that orderly data may be obtained with either a FR or a tandem schedule provided that an appropriate index of discriminative response is employed. The results generally support the validity of current practices, and there will probably be no marked differences between conclusions depending on which schedule is used.

Amphetamine↗

PubMed1971

Observing behavior in squirrel monkeys under a multiple schedule of reinforcement availability.

Observing behavior of two squirrel monkeys was examined under a multiple schedule of four components. Lever (observing) responses produced either a stimulus indicating the availability of food or another stimulus indicating food was not available. Key responses in the presence of the food-available stimulus produced food on a continuous reinforcement schedule. In the absence of food-available stimuli, responding on the key had no scheduled consequences. Observing responses produced food-available stimuli according to three different random-interval schedules with mean interstimulus availability times of 1, 2, and 4 min. In the fourth component of the multiple schedule (observing extinction) food-available stimuli never occurred. Each component of the schedule was correlated with a distinctive auditory stimulus. Observing rates decreased with decreasing frequency of the food-available stimulus. Observing rates during extinction continued decreasing when the brief stimulus indicating food unavailability was no longer produced by lever pressing. When the brief stimulus was reinstated response rates increased abruptly.

Journal Article↗