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Results 501 - 550 of 1334
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Jarema K - - 1999
The present study examined the effects of morphine in pigeons responding under a progressive-ratio 25 schedule of food delivery. Morphine initially reduced response rates and breaking points. With chronic exposure, tolerance developed to these effects. The magnitude of the observed tolerance was not obviously different from that previously reported under ...
Parks B S - - 1999
The dose assessment software CAP88-PC may overestimate doses from tritium under some conditions. The overestimates are linked to three key assumptions implicit in the software that may not be immediately parent. The three assumptions are (1) the contribution of home grown food, (2) the distances at which food is produced, ...
Tsukada Y - - 1999
The imprinting behavior of chicks was quantified as a preference score (correct response ratio) achieved in a running wheel apparatus. A total of 249 chicks were exposed to an imprinting stimulus and tested for stimulus-approaching behavior. The chicks were then classified as good learners (imprinted), poor learners (non-imprinted) and a ...
Farkas A J - - 1999
OBJECTIVE: To determine which smokers report cigarette fading, how much they fade, when fading leads to quitting, and, if not, whether it can be maintained. METHODS: Subjects were 1,682 adult smokers interviewed by telephone in 1990 and 1992 as part of the California Tobacco Survey. Data from three timepoints in ...
Knapp C M - - 1999
The hypothesis that the selective activation of cyclic AMP (cAMP) signal transduction pathways will suppress the initiation of cocaine self-administration was examined in this investigation. To test this hypothesis, the effects of the administration of the cAMP-specific (type IV) phosphodiesterase inhibitors, rolipram and Ro 20-1724, on cocaine self-administration were determined. ...
Cooper L J - - 1999
The authors evaluated the responsiveness of 4 preschool-aged children to positive reinforcers within a concurrent operants paradigm during mealtimes. The children were presented with two identical, concurrently available sets of food. Each set differed in quantity and quality of positive reinforcement paired with acceptance of each bite of food or ...
Weiss S J - - 1999
Experiment 1 demonstrated for the first time a stimulus-reinforcer interaction in pigeons trained with free-operant multiple schedules of reinforcement. Pigeons that treadle pressed in the presence of a tone-light (TL) compound for food exhibited primarily visual stimulus control on a stimulus-element test, whereas pigeons that avoided shock in TL exhibited ...
Aberman J E - - 1999
It has been suggested that nucleus accumbens dopamine is involved in the process of enabling organisms to overcome work-related response costs. One way of controlling work requirements in operant schedules is to use fixed ratio schedules with different ratio requirements. In the present study, the effects of nucleus accumbens dopamine ...
Woolverton W L - - 1999
Previous research has shown that concurrent schedule responding maintained by cocaine under short variable-interval (VI) schedules is well described by the generalized matching law. That is, drug-maintained behavior was apportioned in accordance with relative frequency of reinforcement. The purpose of the present experiment was to examine the ability of the ...
Castejón A M - - 1998
The anticonflict effect of the selective 5-HT3 receptor antagonist, ondansetron, was investigated employing an operant conflict task in pigeons. Behavior (key pecking) was stimulated by food presentation. A fixed-interval program of alternated punished (electrical shocks) and unpunished responding was employed. The effects of drugs were evaluated at two levels punishment ...
Schulteis G - - 1998
Previous studies in rodents have reported that clonidine, an alpha 2-adrenergic receptor agonist, attenuated conditioned aversions to naloxone-precipitated opiate withdrawal when administered prior to each withdrawal conditioning episode. The current study was designed to determine whether clonidine could modify the expression of previously established conditioned place aversions and conditioned suppression ...
Mazur J E - - 1998
In Experiment 1, pigeons' pecks on a green key led to a 5-s delay with green houselights, and then food was delivered on 20% (or, in other conditions, 50%) of the trials. Pecks on a red key led to an adjusting delay with red houselights, and then food was delivered ...
Goldshmidt J N - - 1998
Four pigeons responded on a concurrent-chains schedule in four experiments that examined whether the effectiveness of a stimulus as a conditioned reinforcer is best described by a global approach, as measured by the average interreinforcement interval, or by a local contextual approach, as measured by the onset of the stimulus ...
Bizo L A - - 1998
The amount of food necessary to cause within-session decreases in response rates was investigated by varying reinforcer duration (Experiment 1) and grain size (Experiment 2). Within-session response rates quickly increases to a peak, and the decrease throughout the rest of the session was greater for conditions with larger amounts of ...
Foltin R W - - 1998
During daily 23-h sessions, baboons had concurrent access to food pellets and an oral ethanol/dextrose solution. The effect of increasing the fixed-ratio or "cost" for pellets on pellet and fluid intake was examined when baboons had access to 2%, 4%, or 8% (w/v) ethanol. Increasing the response requirement for a ...
Merzhanova G Kh - - 1998
Cats were initially trained to make operant conditioned food responses to light by an "active selection of reinforcement" method. Provision of low-quality (a mixture of meat and bread) or high-quality (meat) reinforcement depended on the animal pressing a pedal in response to switching on a light with a short (1 ...
Weerts E M - - 1998
The primary aim of the current experiments was to develop methods that engender vocalizations associated with positive social situations comprising affiliative behavior and feeding that could be quantified under controlled laboratory conditions and were sensitive to anxiolytic drugs. Classical conditioning procedures were used to elicit vocalizations during presentation of stimulus ...
Stafford D - - 1998
Key pecking by pigeons was maintained by arithmetic progressive-ratio schedules of food delivery. Successive conditions arranged different step sizes, and each condition remained in effect until behavior appeared stable. Each session continued until a period of time passed in which no key pecks were recorded (the break-point criterion); both a ...
Fucci N - - 1998
Illicit cocaine samples (156), seized on Rome's illegal market between January 1996 and June 1997, were examined. Both the purity of the cocaine and the presence of substances employed for dilution were determined for each sample. Adulterants were found in many of the street samples analysed. Lidocaine (average 14.7%) followed ...
Lamberty Y - - 1998
A new murine model of anxiety, namely the mirror chamber test, is based on the assumption that, like many species, mice show approach-avoidance behavior when they are confronted by a mirror. It has been suggested that the mirror chamber is a specific and a quantitatively/qualitatively different measure of anxiety than ...
Church R M - - 1998
We attempted to determine whether timing theories developed primarily to explain performance in fixed-interval reinforcement schedules are also applicable to variable intervals. Groups of rats were trained in lever boxes on peak procedures with a 30-, 45-, or 60-s interval, or a 30- to 60-s uniform distribution (Experiment 1); a ...
Woolverton W L - - 1998
Several theoretical models of choice, including matching, maximizing and probability matching, have evolved from the experimental analysis of behavior. However, these models are based largely on results of studies involving non-drug reinforcers. The extent to which the choice to self-administer a drug of abuse conforms to these models is largely ...
Aoyama K - - 1998
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 ...
McFarland K K Department of Psychology, University of California, Santa Barbara 93106, - - 1998
The present experiment examined the effects of dopamine receptor antagonism on subjects' motivation to seek food. Rats were trained to discriminate between 2 olfactory cues predicting either the presence (S+) or absence (S-) of food reinforcement in the goal box of a straight-arm runway. Rats learned to traverse the alley ...
Odum A L - - 1998
Four pigeons pecked response keys under a multiple fixed-ratio 30 fixed-interval 5-min schedule of food presentation. Components alternated separated by 15-s timeouts; each was presented six times. Pigeons were maintained at 70%, 85%, and greater than 90% of their free-feeding weights across experimental conditions. When response rates were stable, the ...
Carroll M E - - 1998
The effects of dietary caffeine and the amount and palatability of food on the acquisition of cocaine (0.2 mg/kg) self-administration were examined. Using an autoshaping procedure, seven groups of 13 rats each were trained to press a lever resulting in a cocaine (0.2 mg/kg infusion under a fixed-ratio 1 (FR ...
Holland P - - 1998
The effects of variations in the amount of training on behavioral plasticity were examined in three experiments that used appetitive Pavlovian conditioning procedures with rats. In experiments 1 and 2, an auditory conditioned stimulus (CS) substituted for a food unconditioned stimulus (US) in the acquisition of new learning about the ...
Rudski J J Department of Psychology, Muhlenberg College, Allentown, PA 18104, USA. - - 1998
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 ...
Kerwin M L - - 1998
Food refusal and self-injurious behavior often co-occur in children with developmental disabilities and mental retardation. The subject of the case study was a 3-yr-old boy with food refusal, self-injurious behavior and developmental delay. Using an alternating treatment design, positive reinforcement for acceptance combined with either nonremoval of the spoon or ...
Donny E C - - 1998
The studies presented here were designed to further clarify the nature of nicotine self-administration (SA) based on a limited access model in which rats are food restricted, receive operant training using food reinforcement, and are then tested in daily 1-h drug sessions. We examined the effects of dose, feeding schedule, ...
Sokolowski J D - - 1998
Three experiments investigated the behavioral effects of injections of the neurotoxic agent 6-hydroxydopamine (6-OHDA) into the core or shell of the nucleus accumbens. In the first experiment, it was observed that injections of 6-OHDA into either core or shell had no significant effect on variable interval 30-s responding. In Experiment ...
Panlilio L V - - 1998
In previous experiments, the compounding of two discriminative stimuli associated with the same reinforcer increased rats' responding approximately three-fold, regardless of whether the reinforcer was food, water, cocaine, or shock-avoidance. Compounding a discriminative stimulus associated with food with one associated with water increased responding two-fold. In the present experiment, compounding ...
Mazur J E - - 1998
Two experiments studied the phenomenon of procrastination, in which pigeons chose a larger, more delayed response requirement over a smaller, more immediate response requirement. The response requirements were fixed-interval schedules that did not lead to an immediate food reinforcer, but that interrupted a 55-s period in which food was delivered ...
Meier M - - 1998
The setup, designed for the rodent Meriones unguiculatus (gerbil), allows flexible stimulus presentations and rewarding as well as on-line data registration. It consists of a spacious housing where the animals have free access to water. Food is supplied exclusively in the y-maze training compartment and serves as a reinforcer in ...
Manabe K - - 1998
Call production in budgerigars was studied using operant conditioning. In several experiments, budgerigars were reinforced with food for producing calls that were above or below a criterion level of intensity. This differential reinforcement procedure was successful in controlling vocal intensity in both directions showing that the intensity with which budgerigars ...
Carr J E - - 1998
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 ...
Dieter R A RA - - 1998
On July 27, 1989, six men and 39 sled dogs embarked on the first trans-Antarctic dog, sled, and ski crossing. Data sheets were developed and a review of their day-by-day reports was carried out. The period of time covered is November 3, 1989, to February 10, 1990. Miles traveled were ...
Vollmer T R - - 1998
This study replicates and extends prior research showing that access to self-restraint materials can reinforce self-injurious behavior (SIB). A functional analysis was conducted showing that SIB occurred at differentially high rates when access to restraint materials (a leather jacket) was made contingent on the behavior. In addition, an alone condition ...
Johns K W - - 1998
The conditions under which cues with similar training histories are treated by rats as being equivalent were examined. A significant event, food, either preceded, followed, or preceded and followed each of the Stimuli A and B; Stimulus C was not food-associated. Next, B was counterconditioned with footshock until it suppressed ...
Windecker S - - 1997
INTRODUCTION: While the defibrillation threshold has been reported to increase with ventricular fibrillation (VF) duration for monophasic waveforms, the effect of VF duration for biphasic waveforms is unknown. METHODS AND RESULTS: The ED 50 requirements (the 50% probability of defibrillation success) for an endocardial lead system, which included a subcutaneous ...
Lattal K A - - 1997
The metaphor of the behavior stream provides a framework for studying the effects of response-independent food presentations intruded into an environment in which operant responding of pigeons was maintained by variable-interval schedules. In the first two experiments, response rates were reduced when response-independent food was intruded during the variable-interval schedule ...
Youngblood B D - - 1997
This study investigated whether appetitive operant food reinforcement or free-feeding behavior in rats, food-restricted to 85% of body weight, was disrupted by exposures to 3 h of restraint stress or by 3 h of restraint plus water immersion stress (RWI). Rats were trained under a 3-cycle 10-min time-out-10-min time-in fixed-ratio ...
Evans S M - - 1997
Using a laboratory animal procedure designed to measure two aspects of behavior related to commodity seeking (self-administration and location preference), five individually housed adult rhesus monkeys lived in three chambers: fluid- (sweetened Kool-Aid solution) related cues and oral fluid self-administration were specific to one end chamber, food pellet-related cues and ...
Foltin R W - - 1997
The effects of the availability of an alternative reinforcer on responding maintained by food pellets or fluid solutions were examined in 6 adult male baboons (Papio cynocephalus anubis). During daily 23-hr experimental sessions, baboons had concurrent access to both food pellets and fluid, with responding maintained under fixed-ratio schedules of ...
van den Bergen H - - 1997
We describe an adjustable food delivery system that cuts and delivers calibrated pieces of spaghetti to be used as reinforcers to train mice in an appetitive bar-pressing task. The food delivery is computer-controlled. Uneaten reinforcers are detected and removed automatically. One main advantage of this system is the ability to ...
Yee B K BK Department of Experimental Psychology, Oxford University, - - 1997
Experiment I assessed the effect of cytotoxic retrohippocampal (entorhinal and extra-subicular cortices) lesions on the development of latent inhibition (LI) using an off-the-baseline, between-subjects, conditioned emotional response paradigm. Sham-operated controls and unoperated rats that had been pre-exposed to a light stimulus prior to light-shock pairings showed less conditioned suppression towards ...
Haney M - - 1997
The self-administration of marijuana cigarettes varying in tetrahydrocannabinol (THC) content was measured by having participants choose between marijuana and an alternative reinforcer, i.e., snack food. Twelve marijuana users (eight men, four women), in groups of four, participated in a 16-day residential study. Each day, participants had the opportunity to choose ...
Hunt P S - - 1997
The cardiac responses accompanying conditioned stimulus- (CS)-generated (orienting) and unconditioned stimulus- (US)-generated appetitively motivated behaviors (P. C. Holland, 1977) were investigated. On the basis of contemporary psychophysiological research, CS-generated responses were predicted to produce bradycardia, and US-generated responses to produce tachycardia. Pairing a 10-s visual CS with food delivery produced ...
Geist T D - - 1997
Rats traversing a straight-alley for reinforcing stimuli typically exhibit faster running times as training proceeds. In previous work from this laboratory, animals running for a reinforcement consisting of intravenous infusions of cocaine, unexpectedly demonstrated a progressive increased time to enter the goalbox over trials. Closer observation revealed that the animals ...
Salamone J D - - 1997
Nucleus accumbens (DA) has been implicated in a number of different behavioral functions, but most commonly it is said to be involved in "reward" or "reinforcement". In the present article, the putative reinforcement functions of accumbens DA are summarized in a manner described as the "General Anhedonia Model". According to ...
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