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Results for “Reinforcement Schedule”

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PubMedDate not supplied

Modulation of the behavioral effects of carbon monoxide by reinforcement contingencies.

Behavioral effects of carbon monoxide (CO) were studied in rats during 75-minute exposures in which food reinforcement depended either on 30 lever presses (fixed ratio, FR, 30) or on the first lever press after 3 min (fixed interval, FI, 3 min). Concentrations of 500, 700, and 900 ppm were studied for each rat under at least one of the reinforcement schedules presented singly and under one or more compound schedules (multiple (MULT) FR FI, MULT FR FR, MULT FI FI). Response rates decreased as a function of CO concentrations under all conditions, but overall rate decreases were greater at lower concentrations under the FR schedule than under the FI schedule. Differential effects of CO on the schedule-generated patterns of FR and FI responding were responsible for the differences in rate decreases under those schedules. In some cases, the multiple schedule context attenuated the rate-decreasing effect of CO on FR responding. Differences in magnitude of CO effects were not attributable to previous CO exposures, control response rates, or reinforcement frequency. The extent to which CO disrupts behavior can be a function of the prevailing behavioral contingencies.

Animals↗

PubMed1972

Aversive aspects of a fixed-interval schedule of food reinforcement.

The key pecking of pigeons was reinforced according to a fixed-interval schedule of reinforcement. The pigeons were also given the opportunity to attack a restrained target pigeon. The attack rates during the sessions of fixed-interval reinforcement were higher than during the operant level sessions in four of the five pigeons. Most attack occurred during the post-reinforcement pause in key pecking. It was suggested that a fixed-interval schedule of positive reinforcement possesses aversive properties, the most aversive of which are located during the post-reinforcement pause.

Journal Article↗

PubMed1993

Momentary maximizing in concurrent schedules with a minimum interchangeover interval.

Eight pigeons were trained on concurrent variable-interval variable-interval schedules with a minimum interchangeover time programmed as a consequence of changeovers. In Experiment 1 the reinforcement schedules remained constant while the minimum interchangeover time varied from 0 to 200 s. Relative response rates and relative time deviated from relative reinforcement rates toward indifference with long minimum interchangeover times. In Experiment 2 different reinforcement ratios were scheduled in successive experimental conditions with the minimum interchangeover time constant at 0, 2, 10, or 120 s. The exponent of the generalized matching equation was close to 1.0 when the minimum interchangeover time was 0 s (the typical procedure for concurrent schedules without a changeover delay) and decreased as that duration was increased. The data support the momentary maximizing theory and contradict molar maximizing theories and the melioration theory.

Journal Article↗

PubMed1972

Conditioning of a free operant in Octupus cyaneus Gray.

Operant conditioning was studied in six specimens of Octopus cyaneus Gray. An "arm-out-of-water" operant, in which the octopus inserted an arm up a feeding-tube breaking the water surface, proved susceptible to reinforcement schedules. An apparatus was developed that provided automated reinforcement and recording. Performance was studied under continuous reinforcement, fixed-ratio and variable-ratio schedules, and extinction conditions.

Journal Article↗

PubMed1985

Temporal proximity and reinforcement sensitivity in multiple schedules.

Distributions of reinforcers between two components of multiple variable-interval schedules were varied over a number of conditions. Sensitivity to reinforcement, measured by the exponent of the power function relating ratios of responses in the two components to ratios of reinforcers obtained in the components, did not differ between conditions with 15-s or 60-s component durations. The failure to demonstrate the "short-component effect," where sensitivity is high for short components, was consistent with reanalysis of previous data. With 60-s components, sensitivity to reinforcement decreased systematically with time since component alternation, and was higher in the first 15-s subinterval of the 60-s component than for the component whose total duration was 15 s. Varying component duration and sampling behavior at different times since component transition may not be equivalent ways of examining the effects of average temporal distance between components.

Journal Article↗

PubMed1983

Winter blahs and spring irritability: the chronic but subtle behavioral operations.

Operation analyses, for which behavioral and environmental events are translated into reinforcement schedules, indicate that winter depression and spring irritability reported by people living in northern climates are dominated by four paradigms. They are (1) a shift in the ratio of negative to positive stimuli, (2) stimulus redundancy and satiation, (3) coerced hypoactivity or attenuation of free operant behavior, and (4) conditioned suppression or anxiety due to the progressive escalation of negative stimulus presentations. The chronic effects of these schedules on the behaviors of people living in cold climate during the winter season are discussed.

Anxiety↗

PubMed1994

SDZ 208-911, an amino-ergoline with partial dopamine agonist properties, dose dependently increases cocaine self-administration in the rat.

Brain dopamine neurotransmission appears to be an important component of the neural pathways involved in the maintenance of intravenous (IV) cocaine self-administration in rats. The effects of a novel partial dopamine agonist, SDZ 208-911, on intravenous cocaine self-administration in rats was studied. SDZ 208-911 at a dose range of 0.025-1.6 mg/kg SC dose-dependently increased the number of lever presses and drug intake in rats exposed to limited (3-h) daily access to cocaine on a continuous reinforcement schedule (0.75 mg/kg per injection). This behavioral profile is similar to that observed following administration of dopamine antagonist drugs and has been hypothesized to reflect a compensatory increase in drug intake due to a reduction of the reinforcing efficacy of the drug, probably because of functional antagonism at the receptor site. These results suggest that dopamine partial agonists may act as functional dopamine antagonists in the face of pharmacologically induced activation of brain dopamine function.

Animals↗

PubMed2001

Human large-scale oscillatory brain activity during an operant shaping procedure.

The present study aimed at examining the oscillatory brain-electric correlates of human operant learning using high-density electroencephalography (EEG). Induced gamma-band activity (GBA) was studied using a fixed-interval reinforcement schedule with a variable limited hold period, which was decreased depending on response accuracy. Thus, participants' behavior was shaped during the course of the learning session. After each response, numbers indicating the money value of that response served as reinforcing stimuli. Random reinforcement and self-paced button pressing without reinforcement were added as control conditions. GBA around 40 Hz was enhanced at posterior electrodes in response to visual feedback stimuli during shaping and random reward compared to the self-paced pressing condition where no visual feedback was provided. Furthermore, shaping was associated with a pronounced left frontal lower gamma (20-30 Hz) increase in response to feedback stimuli, whereas this pattern was not observed in the random reinforcement and self-paced pressing conditions. The present findings are in line with the notion that macroscopic high-frequency dynamics of neuronal cell assemblies may be regarded as a mechanism involved in learning and memory formation.

Adult↗

PubMed1991

Differential effects of an early housing manipulation on cocaine-induced activity and self-administration in laboratory rats.

Several reports in the literature suggested that environmental influences which are reflected in the social housing conditions of the rat may play a role in the expression of individual differences in drug self-administration. The present experiments were performed in order to further examine the effects of early housing manipulations, as reflected by grouped or isolation housing, on cocaine-induced behavioral responding. The first study examined the effects of this manipulation on the locomotor stimulant properties of cocaine. The results suggested that grouped housing produced a significantly greater increase in cocaine-induced locomotion than was observed in animals housed in isolation. Experiment 2 examined the effects of housing manipulations on the self-administration of cocaine under a continuous reinforcement schedule. Differences in the rate of cocaine self-administration were only observed at the lowest dose tested. Responding at all other doses was equivalent, including the optimal dose for both groups, suggesting that the housing manipulations failed to affect the reinforcing efficacy of cocaine. The present investigation suggests that, while the early housing manipulation produced a differential sensitivity in rats to the stimulant properties of cocaine, the same manipulation failed to alter the sensitivity of rats to the reinforcing properties of cocaine as assessed through self-administration.

Analysis of Variance↗

PubMed1977

Preclinical effects: learned behavior.

A review of the previous Marihuana and Health Reports (1971-1975) reveals that an extensive array of experimental procedures and contexts have been used to study the effects of cannabinoids on the performance of learned behavior in animals. These preclinical behavioral experiments have provided a framework for, and guided the design of, subsequent human experimentation. Compared to previous years, only a few experiments pertaining to cannabinoids and learned behavior have appeared during the past two years. By and large these more recent experiments confirm previous findings; no particularly novel procedures have been explored nor have there been dramatically unpredictable results. In part, the decrease in activity in cannabinoid preclinical animal research on learned behavior indicates an increase in human cannabinoid-learning investigations. Several detailed taxonomies of learned behavior are possible. However, for the purposes of the present report, learned behaviors will be categorized into those involving: avoidance learning and aversive control; reinforcement schedules and maze learning; and discrimination learning.

Animals↗

PubMed1987

Effect of dopamine agents on schedule- and deprivation-induced drinking in rats.

The dopamine agonist, apomorphine, or its antagonist, haloperidol, was administered to rats whose drinking was induced by fixed-interval schedules of pellet delivery or by water deprivation. The first study revealed that both drugs produced dose-dependent decreases in bar-pressing and schedule-induced polydipsia (SIP). At higher doses, haloperidol also depressed the rate of pellet delivery. The second study demonstrated that the suppression in SIP obtained in the first study was primarily due to the direct effect of the drugs and not to changes they produced on the underlying food reinforcement schedule. The third study showed that both drugs suppressed water deprivation-induced drinking during a ten-minute session. Apomorphine delayed the onset of drinking, while haloperidol accelerated the cessation of drinking. The results indicated that apomorphine produced motor deficits that interfered with consummatory behavior, and that haloperidol interfered with the sensory feedback necessary to sustain consummatory behavior.

Animals↗

PubMed1975

A choice procedure for drug reinforcers: cocaine and methylphenidate in the rhesus monkey.

A choice procedure was developed to compare the reinforcing efficacy of drug solutions delivered via intravenous catheters to rhesus monkeys. Choices were arranged between doses of cocaine or methylphenidate and saline, different doses of the same drug and doses of both drugs. In each session, monkeys were allowed to self-inject one solution five times in the presence of a stimulus. Thirty minutes after the fifth injection, a second solution could be self-injected five times in the presence of a different stimulus. Thirty minutes later, choice trials began in which both stimuli were present and monkeys could choose one of the two solutions. Rate of responding decreased with increases in dose for both cocaine (0.05-1.5 mg/kg) and methylphenidate (0.075-0.7 mg/kg). Response rates maintained by cocaine were 2 to 3 times higher than those maintained by methylphenidate. Drug was always chosen over saline. Higher doses of cocaine were preferred to lower doses except when both were above 0.5 mg/kg, when no preference was shown. Higher doses of methylphenidate were preferred over low doses, but compared to cocaine, a greater absolute difference between dose magnitude was required to demonstrate preference. When equal doses of cocaine and methylphenidate were compared, no preference was shown. On other comparisons between the drugs, the higher dose was generally preferred regardless of the drug. The reinforcing efficacy of drugs must be considered not only in terms of response rate maintained or reinforcement schedule but also with reference to concurrently available drugs.

Animals↗

PubMed1968

The relation between response rates and reinforcement rates in a multiple schedule.

In a multiple schedule, exteroceptive stimuli change when the reinforcement schedule is changed. Each performance in a multiple schedule may be considered concurrent with other behavior. Accordingly, two variable-interval schedules of reinforcement were arranged in a multiple schedule, and a third, common variable-interval schedule was programmed concurrently with each of the first two. A quantitative statement was derived that relates as a ratio the response rates for the first two (multiple) variable-interval schedules. The value of the ratio depends on the rates of reinforcement provided by those schedules and the reinforcement rate provided by the common variable-interval schedule. The following implications of the expression were evaluated in an experiment with pigeons: (a) if the reinforcement rates for the multiple variable-interval schedules are equal, then the ratio of response rates is unity at all reinforcement rates of the common schedule; (b) if the reinforcement rates for the multiple schedules are unequal, then the ratio of response rates increases as the reinforcement rate provided by the common schedule increases; (c) the limit of the ratio is equal to the ratio of the reinforcement rates. Satisfactory confirmation was obtained for the first two implications, but the third was left in doubt.

Animals↗

PubMed1978

Self-administration of morphine in the rat: relative influence of fixed ratio and time-out.

Rats were offered 3.2 mg/kg of morphine sulfate on a continuous reinforcement schedule until the daily injection rate had stabilized. The effect of fixed ratio schedules of 4 and 8 were compared to imposing time-out periods of 5 and 10 sec immediately followed each injection. The fixed ratio schedules decreased the injection rate while the time-out schedules had no effect. The hypothesis that the effect of a fixed ratio schedule is a consequence of imposing a time-out period, allowing full effects of the injection to be sensed, is not supported.

Animals↗

PubMed1989

Serotonin-antagonist effects of 1-(1-naphthyl)piperazine on operant behavior of squirrel monkeys.

1-(1-Naphthyl)piperazine (1-NP) has been reported to have serotonin antagonist properties at the 5-HT2 subtype of receptor, and it has been suggested that it may have agonist actions at the 5-HT1 site. In the present experiments, the effects of 1-NP alone and in combination with a variety of 5-HT agonists, were studied in squirrel monkeys performing under a number of reinforcement schedules. The phenalkylamine hallucinogen 4-bromo-2,5-dimethoxyamphetamine (DOB, 0.01-0.3 mg/kg), which is thought to have predominant actions at 5-HT2 sites, reduced responding under fixed-interval (FI) schedules of presentation of food, and these decreases were blocked by 1-NP (0.3-1.0 mg/kg) or by the selective 5-HT2 antagonist, ketanserin (0.3 mg/kg). 1-(1-Naphthyl)piperazine also antagonized the decreases in responding produced by quipazine (0.1-5.6 mg/kg), another agonist with predominant 5-HT2 actions. 1-(m-Chlorophenyl)piperazine (mCPP, 0.1-3.0 mg/kg) and 1-(m-trifluoromethylphenyl)piperazine (TFMPP, 0.1-3.0 mg/kg), both thought to act primarily at 5-HT1 sites, also decreased responding and this effect was blocked by methysergide and by 1-NP, but not by ketanserin. The effects of 1-NP (0.3-5.6 mg/kg) given alone were not like those of mCPP or TFMPP. 1-(1-Naphthyl)piperazine produced moderate increases in responding under shock-avoidance schedules, whereas only decreases in responding were seen after mCPP and TFMPP.(ABSTRACT TRUNCATED AT 250 WORDS)

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed1998

Withdrawal of presession saccharin suppresses food-maintained responding in rats.

Decreased motivation following drug withdrawal is often characterized as indicative of addiction. Similar behavioral disruptions are seen in negative contrast paradigms. In the current study, 7 rats with a history of access to a palatable 0.15% saccharine solution before operant sessions were conditioned. Rats responded for food under a multiple FR 5 FR 40 reinforcement schedule. When presession saccharin was removed and replaced with water, responding maintained by food was significantly decreased, with greater effects observed under the FR 40 schedule. These results support the assertion that behavioral disruptions accompanying withdrawal syndromes include a negative contrast component.

Animals↗

PubMed1981

Activity changes in rats following acute trimethyltin exposure.

The aliphatic organo-metal derivative, trimethyltin, causes marked morphological damage to the central nervous system (CNS), when the compound is administered by the intragastric route. This report describes certain behavioral consequences of [CH3]3Sn treatment. Either 7.0 mg/kg [CH3]3SnCl or 0.9% saline was injected intragastrically in male rats of Long-Evans strain divided into two equal groups of nine each. Forty days later open-field activity during a 2-min interval was measured for each rat. Following activity testing, the animals were trained to press a lever for food reinforcement on an ascending fixed-ratio series ranging from FR 2 to FR 99. The results showed that rats treated with [CH3]3SnCl were three times as active as controls in the open field, and emitted lever responses at a significantly higher rate than controls throughout the fixed-ratio series regardless of the reinforcement schedule. The possible neuropathological consequences and the relative permanence of the neurobehavioral changes following tin treatment are discussed.

Animals↗

PubMed1986

Schedule-shifts, circadian rhythms and lifespan of freely-feeding and meal-fed mice.

Mice feeding ad lib were subjected to weekly 12-hr shifts of the daily light-dark (LD) schedule beginning at either 7, 20 or 52 weeks of age and continuing until death. Other mice were meal-fed and, from 7 weeks of age until death, experienced weekly 12-hr shifts of the LD schedule alone (with mealtime fixed) or of both the LD schedule and mealtime. Telemetered core temperature data indicated marked differences in response to the different shift conditions and suggested, in the case of meal-fed animals, involvement of a food-anticipatory rhythm. Shifting of the LD schedule had no statistically significant effect on the mean survival time of mice feeding ad lib, regardless of when shifting began. While meal-feeding in itself prolonged life, the added imposition of schedule-shifting had no statistically significant effect on mean survival time, regardless of whether the meal schedule reinforced or opposed shifts of the LD schedule. In the latter case, tenth-decile survival time may have been increased.

Aging↗