Search Results
Results 451 - 500 of 1347
< 5 6 7 8 9 10 11 12 13 14 15 >
Hagopian L P - - 2001
Although response blocking can decrease problem behavior, one potential adverse side effect is the induction of aggression. In the current study, we report on a young adult who engaged in high rates of pica maintained by automatic reinforcement. Blocking pica, however, led to aggression. When redirection to an alternative preferred ...
Murphy R A - - 2001
Two experiments investigated the relative validity effect with either 1 or 2 continuously reinforced cues in Wistar rats using appetitive Pavlovian and instrumental preparations. Discrimination training involved 3 compound cues containing a common element (1AX: 1BX: 2CX). In the first true-discrimination group (TD-1), CX was followed by food, but AX ...
Bornhausen M - - 2000
To clarify potential health risks of radio-frequency electromagnetic fields (EMFs) used in cellular telephone technology to the developing brain, Wistar rats were continuously exposed during pregnancy to a low-level (0.1 mW/cm(2)) 900 MHz, 217 Hz pulse modulated EMF that approximated the highest legal exposure of normal populations to the radiation ...
Donahoe J W - - 2000
Revaluation refers to phenomena in which the strength of an operant is altered by reinforcer-related manipulations that take place outside the conditioning situation in which the operant was selected. As an example, if lever pressing is acquired using food as a reinforcer and food is later paired with an aversive ...
Leslie J C - - 2000
In Experiments 1 and 2, lever pressing by rats was reinforced on a cyclic ratio schedule of food reinforcement, comprising a repeated sequence of fixed-ratio component schedules. Reinforcement magnitude was varied, on occasional sessions in Experiment 1 and across blocks of sessions in Experiment 2, from one to two or ...
Robbins L A - - 2000
We describe a portable apparatus designed to examine the free-operant food preferences of captive coyotes in their home kennels. Because lever-pressing for food access was the dependent variable, we measured food preference independently of food ingestion. Using successive approximation, we trained 8 out of 19 coyotes (42%) to use the ...
Kelly R - - 2000
Two experiments investigated the effects of similarity between intertrial interval (ITI) and delay illumation on the choose-short effect. Different groups of pigeons learned to match "short" (2 s) and "long" (6 or 8 s) food samples to green and red test stimuli in a matching-to-sample procedure with a 5-s training ...
Horvitz J C - - 2000
Parkinsonian behavioral deficits are reduced in the presence of strong eliciting stimuli and are most pronounced when the response requires internal generation. In the present study, rats' head entries into a food compartment were measured in the presence and absence of an eliciting stimulus. The D2 receptor blocker raclopride suppressed ...
Gamoke C A - - 2000
Prolactin (Prl) increases food consumption in ring doves (Streptopelia risoria) and may promote the hyperphagia exhibited by parent doves when provisioning young. These experiments tested whether Prl also enhances appetitive aspects of feeding behavior. Prl elevated pecking rates in food-restricted doves on a variable-interval (VI) reinforcement schedule and supported continued ...
Pietras C J - - 2000
Three experiments were conducted to examine pigeons' postponement of signaled extinction periods (timeouts) from a schedule of food reinforcement when such responding neither decreased overall timeout frequency nor increased the overall frequency of food reinforcement. A discrete-trial procedure was used in which a response during the first 5 s of ...
Kitfield E B - - 2000
A negative reinforcement-based treatment package was associated with desirable weight gain in a 22-year-old woman with developmental disabilities who demonstrated chronic food refusal. Treatments including extinction of escape and continuous access to preferred foods were not successful in increasing her weight. The negative reinforcement intervention included escape from eating and ...
Miyashita Y - - 2000
Three horses were trained with a discrimination task in which the color (blue or yellow) of a center panel signaled the correct (left or right) response (lever press). Reinforcing outcomes for the two correct color-position combinations (blue-left and yellow-right) were varied across phases. Discrimination performance was better when the combinations ...
Grace R C - - 2000
Two experiments explored preference and resistance to change in concurrent chains in which the terminal links were variable-interval schedules that ended either after a single reinforcer had been delivered (variable duration) or after a fixed period of access to the schedule (constant duration). In Experiment 1, pigeons' preference between the ...
Lile J A - - 2000
Research has shown that many variables influence the reinforcing effects of drugs. The purpose of the present study was to compare the reinforcing effects of cocaine and the long-acting cocaine analogue 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) in rhesus monkeys during the 1st versus the last day of substitution. When PTT and cocaine were ...
Middaugh L D LD Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, USA. - - 2000
Operant experiments which indicate that ethanol can serve as a reinforcer to maintain lever responding during limited periods of access have not been conducted on non-food-deprived mice, as they have for rats and monkeys. Furthermore, there are no reports of the effects of chronic ethanol and subsequent abstinence on ethanol ...
Cabib S - - 2000
Inbred strains of mice are largely used to identify the genetic basis of normal and pathological behaviors. This report demonstrates that a moderate period of food shortage, an ecologically common experience, can reverse or abolish strain differences in behavioral responses to the abused psychostimulant amphetamine. The period of food shortage ...
Nevin J A - - 2000
Previous research on preference between variable-interval terminal links in concurrent chains has most often used variable-duration terminal links ending with a single reinforcer. By contrast, most research on resistance to change in multiple schedules has used constant-duration components that include variable numbers of reinforcers in each presentation. Grace and Nevin ...
Mazur J E - - 2000
Two experiments with pigeons used concurrent-chain procedures with variable-interval schedules as initial links and different delays to food as terminal links. Two schedules were present in all sessions, but a 3rd schedule was alternately present and absent in successive sessions. When the 3rd schedule delivered food with no terminal-link delay, ...
Luiselli J K - - 2000
A 3-year-old child with multiple medical disorders and chronic food refusal was treated successfully using a program that incorporated antecedent control procedures combined with positive reinforcement. The antecedent manipulations included visual cueing of a criterion number of self-feeding responses that were required during meals to receive reinforcement and a gradual ...
Carelli R M RM Department of Psychology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3270, USA. - - 2000
Electrophysiological recording procedures were used to examine nucleus accumbens (Acb) cell firing in rats trained to press a lever on a multiple schedule [ fixed ratio (FR)1, FR1] for either two "natural" reinforcers (food and water), or a natural reinforcer and intravenous self-administration of cocaine. Of 180 cells recorded during ...
Wolgin D L - - 2000
A growing literature attests to the fact that the environment in which a drug is given can have a profound effect on the development and expression of tolerance and sensitization. The dominant paradigm for studying such context-dependency is based on Pavlovian conditioning, in which a distinctive environment serves as a ...
Hazlett BA - - 2000
We recorded the responses of individual intertidal crabs, Heterozius rotundifrons, to stimuli presented singly and in combinations in the laboratory. Undisturbed crabs did not respond to the introduction of odour from a crushed conspecific but did respond strongly to food odour. Undisturbed crabs responded equally to food odour alone and ...
Kirkpatrick K - - 2000
In 2 experiments, separate groups of rats were given stimulus conditioning, temporal conditioning, untreated control and (in Experiment 2) learned irrelevance control procedures, followed by a compound with both stimulus and temporal cues. Stimulus conditioning consisted of a random 15-s duration conditioned stimulus (CS) followed by food; temporal conditioning consisted ...
Ono K - - 2000
Preferences in pigeons for free choice over forced choice under uncertain contingencies were compared with the one under certain contingencies in multiple concurrent-chain schedules of reinforcement. The uncertain condition examined the preference for two alternatives over one alternative when reinforcement probability at the end of the terminal link equalled 0.5, ...
Mazur JE - - 2000
In Experiment 1, an adjusting-delay procedure was used to measure pigeons' choices between a single delayed reinforcer and a range of different variable-time schedules. Indifference points showed an inverse relation between rate of reinforcement and delay that was well described by a hyperbolic equation. An adjusting-amount procedure was used in ...
Weatherly JN - - 2000
The present study investigated whether the sucrose-reinforced lever pressing of rats in the first half of a 50-min session would be sensitive to upcoming food-pellet reinforcement in the second half. In Experiment 1, the type of reinforcer in the first half of the session was always liquid sucrose and type ...
Carroll M E - - 2000
RATIONALE: Previous results suggested that naltrexone had opioid-selective effects on behavior reinforced by orally delivered drugs and food. The present study explores the possibility that previous results were due to presentation of the reinforcers in a closed economy (all reinforcers earned by subjects) and that naltrexone's effect may be nonselective ...
Foltin R W - - 2000
The effects of oral d-amphetamine (0.12-1.0 mg/kg) on the responding of adult baboons were examined during choice sessions. In Experiment 1, responding on 1 lever was reinforced with 1 food pellet, and responding on a 2nd lever was reinforced with 4 food pellets. The response requirement (fixed ratio [FR]) on ...
Slawecki C J - - 2000
Long-term ethanol exposure has been reported to produce electrophysiological and cognitive impairments in some alcoholics. This study assessed the effects of chronic ethanol exposure on neurophysiological indices of associative learning in rats. Male Wistar rats (46) were exposed to ethanol vapor (EtOH group) or air (control group) for 6 consecutive ...
Lett B T - - 2000
Wheel running reinforces behavior that precedes it. Also, wheel running can produce activity anorexia, a marked suppression of feeding in food-restricted rats. Some authors propose that the activity anorexia effect is produced by activation of the same reward system that mediates the reinforcing effect. One hypothesis is that such activation ...
Self D W - - 2000
Selective D1 dopamine agonists represent a potential pharmacotherapy for the treatment of cocaine addiction. Here we report that systemic injections of the novel D1 agonist ABT-431 lack the ability to induce cocaine-seeking behavior, and completely attenuate the ability of cocaine to induce this behavior in rats tested in a reinstatement ...
Kahng S W - - 2000
We compared two methods for programming and thinning noncontingent reinforcement (NCR) schedules during the treatment of self-injurious behavior (SIB). The participants were 3 individuals who had been diagnosed with mental retardation. Results of functional analyses indicated that all participants' SIB was maintained by positive reinforcement (i.e., access to attention or ...
Spieler R E - - 1999
Based on the hypothesis that neuronal histamine exerts an inhibitory influence on learning and reinforcement, goldfish were tested for post-trial effects of the H1 receptor blocker chlorpheniramine (CPA) on learning the location of a food source in one of two compartments, one black the other white, with a feeder located ...
Lewis D B - - 1999
An investigation into the preparation of potential extended-release cocaine-abuse therapeutic agents afforded a series of compounds related to 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine (1a) and 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine (1b) (GBR 12935 and GBR 12909, respectively), which were designed, synthesized, and evaluated for their ability to bind to the dopamine transporter (DAT) and to inhibit the uptake ...
Stafford D D Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, Shreveport 71130-3932, - - 1999
Previous reports indicate that intravenous pretreatment with phentermine can decrease cocaine-maintained responding without affecting food-reinforced responding under fixed-ratio schedules. The present experiments were designed to explore the generality of this effect using progressive-ratio schedules of reinforcement and different routes of phentermine administration. Unit doses of cocaine and food-pellet magnitudes were ...
Macenski M J - - 1999
Four rhesus monkeys (Macaca mulatta), maintained at reduced body weight and restricted food availability, had access to a 0.8-mg/ml cocaine solution and vehicle under a concurrent fixed-ratio (FR) 8 schedule. Over days, the cocaine concentration was reduced (0.57, 0.4, 0.2, 0.1, 0.05, 0.025) and then returned, gradually over days, to ...
Bowers W J WJ Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, Quebec, - - 1999
The effect of a single exposure to foot shock stress on runway responding for food reinforcement was assessed in animals trained and tested with the same or changed reinforcement magnitude. Foot shock (30 1-s shocks, 1.0 mA) exerted no impact on runway responding in animals trained and tested with the ...
Astley S L - - 1999
Training associated pairs of perceptually dissimilar stimulus classes with a common delay or probability of food reinforcement in pigeons. Then, different choice responses were trained to 1 component class in each pair. In a choice test, the untrained class in each pair occasioned the same response as did the choice-trained ...
Williams B A - - 1999
Rats learned a series of reversals of a positional discrimination in which responses to one lever led to delayed food and responses to a second lever led to no food. Interpolated within the delays leading to the different outcomes were two-link stimulus chains. The pairing of each stimulus element with ...
Foltin R W - - 1999
The effects of the availability of an alternative reinforcer on responding maintained by food pellets or drug solutions were examined in 8 adult male baboons (Papio hamadrayas anubis). During daily 23-hr experimental sessions, baboons had access to both food pellets and fluid under a two-choice procedure, in which the response ...
Gallagher M - - 1999
Clinical evidence indicates that damage to ventromedial prefrontal cortex disrupts goal-directed actions that are guided by motivational and emotional factors. As a consequence, patients with such damage characteristically engage in maladaptive behaviors. Other research has shown that neurons in the corresponding orbital region of prefrontal cortex in laboratory animals encode ...
Chase A R - - 1999
As part of ongoing research into the ability of koi to categorize complex auditory stimuli, we have had to develop novel apparatus. The stimulus generator presents sound from two CD drives under computer control through a new underwater speaker. The operant manipulandum is a horizontal button that eliminates spurious triggering ...
Prescott J - - 1999
Studies using capsaicin-saturated filter papers have shown that the intensity of oral irritation tends to grow over successive samples, a phenomenon known as sensitization. If a hiatus of 5-15 min is then introduced, the intensity of irritation produced by a subsequent capsaicin stimulus is much reduced, and desensitization is said ...
Mazur J E - - 1999
Pigeons were presented with a concurrent-chains schedule in which terminal-link entries were assigned to two response keys on a percentage basis. The terminal links were fixed delays that sometimes ended with food and sometimes did not. In most conditions, 80% of the terminal links were assigned to one key, but ...
Horn C C - - 1999
Application of food (seaweed, SW) stimuli to the lips evokes a burst of metacerebral cell (MCC) spikes, and it was found in free-moving animals that repeated presentation of the stimulus was associated with a rapid decrement of the evoked responses, even in the absence of ingestion of the food. To ...
Kleven M S - - 1999
RATIONALE: Although all of the benzodiazepines in use for the treatment of anxiety are presumably full agonists, it is conceivable that partial benzodiazepine agonists may also be clinically effective on the basis of their effects in preclinical models of anxiety. OBJECTIVES: To compare the anxiolytic-like effects of different pharmacological/chemical classes ...
McFarland K - - 1999
The present study examined whether a discriminative cue previously predictive of food or heroin reinforcement could activate and direct behavior in an environment that had never been paired with primary reinforcement. Olfactory cues, predicting the availability (S+) or unavailability (S-) of either heroin (0.1 mg/kg i.v.) or food (45 mg ...
Parkinson J A JA Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom CB2 - - 1999
Dopamine release within the nucleus accumbens (NAcc) has been associated with both the rewarding and locomotor-stimulant effects of abused drugs. The functions of the NAcc core and shell were investigated in mediating amphetamine-potentiated conditioned reinforcement and locomotion. Rats were initially trained to associate a neutral stimulus (Pavlovian CS) with food ...
Foltin R W - - 1999
Using a laboratory animal procedure designed to measure two aspects of reinforcement (self-administration and location preference), five adult rhesus monkeys each lived in three chambers: oral cocaine self-administration (0.26 mg/kg/delivery cocaine hydrochloride in a sweet fluid) was specific to one end chamber, food self-administration was specific to the other end ...
Madsen B - - 1999
The mechanical characteristics of dragline silks collected from a range of spiders drawn from the Argiopidae, Tetragnathidae, Theridiidae and Pisauridae displayed significant inter- and intraspecific differences. Dragline silks of the same species could show considerable variability probably dependent upon spider condition: starvation, for example, lead to decreased breaking elongation in ...
< 5 6 7 8 9 10 11 12 13 14 15 >