Search Results
Results 551 - 600 of 1334
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Glowa J R - - 1997
Dopaminergic agonists can decrease cocaine self-administration at doses that do not decrease food-maintained responding, a pre-clinical effect indicative of a potential treatment for human cocaine abuse. To assess whether similar effects could be obtained with medications currently used to treat substance abuse, phentermine and fenfluramine were given alone and in ...
O'Hare E O - - 1997
The suppression of food intake observed following naloxone administration has often been ascribed to palatability or taste. Unfortunately, many confounds become apparent when attempts are made to isolate such factors in the investigation of ingestive behaviors. In the present study, rats (two groups) were trained to discriminate either a 10% ...
Maes J H - - 1997
The present two experiments examined conditional control by midazolam and amphetamine cues in an appetitive discrimination procedure. In each of two experiments, male Wistar rats were subjected to a small number of two types of training sessions in a conditioning box. During one type of session, a stimulus was consistently ...
Zarcone T J - - 1997
Key pecking by 7 pigeons was established and maintained on a multiple variable-ratio variable-ratio (VR) schedule of food presentation. The schedule in one of the components was then changed to fixed-ratio (FR) 1 for a predetermined number of reinforcers. Both components were then changed to extinction (i.e., multiple extinction, extinction). ...
DeLeon I G - - 1997
Identification of reinforcers for individuals with developmental disabilities is often based on the outcome of preference assessments in which participants make selections from among a variety of items. We determined the extent to which individuals might show a general preference for food items over leisure items during such assessments and ...
Ploog B O - - 1997
The relation between variables that modulate the probability and the topography of key pecks was examined using a concurrent variable-interval variable-interval schedule with food and water reinforcers. Measures of response probability (response rates, time allocation) and topography (peck duration, gape amplitude) were obtained in 5 water- and food-deprived pigeons. Key ...
DeLeon I G - - 1997
Tustin (1994) recently observed that an individual's preference for one of two concurrently available reinforcers under low schedule requirements (concurrent fixed-ratio [FR] 1) switched to the other reinforcer when the schedule requirements were high (concurrent FR 10). We extended this line of research by examining preference for similar and dissimilar ...
Williams B A - - 1997
In two experiments rats were trained on three-link concurrent-chains schedules of reinforcement. In Experiment 1, additional entries to one terminal link were added during one of the middle links to a baseline schedule that was otherwise equal for the two chains, and, depending on the condition, these additional terminal-link presentations ...
Rodefer J S - - 1996
The effect of feeding conditions on the reinforcing efficacy of orally-delivered drugs was evaluated using a progressive-ratio (PR) paradigm and a behavioral economic analysis of demand. Seven monkeys self-administered phencyclidine (PCP) (0.06, 0.12, 0.25, 0.5, and 1.0 mg/ml) or ethanol (2, 4, 8, 16, and 32% wt/vol) and concurrent water ...
McSweeney F K - - 1996
Rats and pigeons responded on several concurrent schedules that provided different reinforcers in the two components (food and water for rats, Experiment 1; wheat and mixed grain for pigeons, Experiment 2). The rate of responding and the time spent responding on each component usually changed within the session. The within-session ...
Kravtsov A N - - 1996
Experimental data were obtained on the nature of rabbit sensorimotor cortex neuron reactions to stimulation of the food motivation center of the lateral hypothalamus in conditions in which food was or was not presented to the animals combined with microiontophoretic application of tetragastrin and bradykinin. These neuropeptides were able to ...
Dickinson A - - 1996
Three experiments examined bidirectional instrumental conditioning by training hungry rats to push a pole in one direction for food pellets and in the other for either a sugar or a starch solution. In the first study we examined whether the animals learned about the action-reinforcer relations using a specific satiety ...
Schmelzeis M C - - 1996
Two experiments investigated the effects of ibotenic-acid lesions of the hippocampus on food-rewarded performance under a progressive-ratio 10 schedule of reinforcement. The results of Experiment 1 indicated that rats with hippocampal lesions showed profound increases in breakpoint and enhancements in the efficiency of responding. In a second experiment the same ...
Charlop-Christy M H - - 1996
We assessed the effectiveness of using the obsessions of children with autism to reduce their inappropriate behaviors. Baseline consisted of a traditional differential reinforcement of other behaviors (DRO) in which food reinforcers were provided contingent upon a period of nonoccurrence of the inappropriate behaviors. Then, three treatment conditions were assessed ...
Cherot C - - 1996
Anticipation of rewards had different effects on operant variability than on operant repetition. We reinforced variable (VAR) response sequences in groups of rats and pigeons and repetitive (REP) response sequences in separate groups. A fixed number of variations or repetitions was required per food reinforcer (e.g., fixed-ratio 4). Although VAR ...
LeSage M - - 1996
Previous studies have found that defecation increases in rats exposed to fixed-time schedules of dry food delivery. The purpose of the present study was to examine whether increases in defecation could be induced in rats exposed to fixed-time schedules of liquid food delivery. Eight rats were exposed to fixed-time 30-, ...
Saelens B E - - 1996
Food is a powerful reinforcer, and individual differences in the reinforcing efficacy of food may provide a mechanism to explain the excess intake and positive energy balance responsible for obesity. The present study tested the hypothesis that eating palatable food would be more reinforcing than engaging in sedentary activities (e.g. ...
Slawecki C J - - 1996
A multiple schedule (Mult FR 10 VI 30") was employed to examine the interaction of reinforcement schedule and food restriction on amphetamine's effects on lever pressing behavior. High response rates were observed in fixed ratio (FR) 10 components. Significantly lower response rates were observed under the variable interval (VI) 30" ...
Jackson K - - 1996
Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred ...
Mazur J E - - 1996
A discrete-trials adjusting-delay procedure was used to investigate the conditions under which pigeons might show a preference for partial reinforcement over 100% reinforcement, an effect reported in a number of previous experiments. A peck on a red key always led to a delay with red houselights and then food. In ...
Burns M - - 1996
Pairings of a conditioned (CS) and unconditioned (US) stimulus can result in approach to either the CS (sign tracking) or the US (goal tracking). Increasing the spatial or temporal separation between the CS and a US food has been reported to results in a decline in sign tracking and an ...
Johnson P I PI Department of Psychology, Northeastern University, Boston, MA 02115, - - 1996
The role of the nucleus accumbens (NAC) and ventral pallidum (VP) in food reward modulation was investigated using Heyman's [24] curve fitting approach in food deprived rats. All rats were maintained at 80% normal body weight, and trained to lever press for food reinforcement. Each rat was tested daily with ...
Harper D N - - 1996
Response-independent food was delivered during a dark-key phase between two multiple-schedule components to explore its disruptive effects on responding. Responding in components was maintained by separate variable-interval 120-s schedules, with a 2-s reinforcer in Component 1 and a 6-s reinforcer in Component 2. Across conditions the rate and duration of ...
Balleine B W - - 1996
These experiments assessed whether reported increases in food consumption and food-reinforced instrumental performance in undeprived rats by the 5-HT1A agonist 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) are due to an increment in the incentive value of foods. Against this hypothesis, we found that when undeprived rats were trained to lever press for the food ...
Khallad Y - - 1996
Three experiments used pigeons in an autoshaping procedure and a single-subject design to examine compound stimulus control in classical conditioning. Experiment 1 examined the blocking effect, and Experiment 2 examined the unblocking effect. In both experiments, response-independent food was first delivered intermittently in the presence of one distinctively colored houselight ...
Koerhuis A N - - 1996
1. Direct versus indirect selection for food conversion ratio of growth (FCR) after selection for live body weight (LWT), a sequential scheme often applied in broilers, was considered. In the present study loss of response in either FCR or aggregate genotype (H) when LWT was included was investigated under selection ...
Salamone J D - - 1996
Rats were tested using a lever pressing/feeding procedure in which a preferred food (Bioserve pellets) was available by pressing a lever on a fixed ratio 5 schedule, but a less preferred food (lab chow) was also available concurrently in the operant chamber. The effects of repeated (14 day) injections of ...
Gahtan E - - 1996
The purpose of the present experiment was to replicate previously reported observations of a relationship between saccharin consumption and oral ethanol self-administration in rats using operant measures (2,8) and to determine whether saccharin intake was related to the rate of acquisition of IV cocaine self-administration. Groups of Wistar rats selected ...
Teyke T - - 1996
The effects of inhibition of nitric oxide (NO) or serotonin (injection of nitro-L-arginine methyl ester (L-NAME) or 5,6-dihydroxytryptamine (5,6-DHT), respectively) on food-attraction conditioning was investigated in Helix. Blocking NO synthase (NOS) prior to conditioning significantly impaired the food-finding ability of the snails. Food-conditioned snails, after inhibition of NOS, remained able ...
Wacker D P - - 1996
We present 2 case examples that illustrate the effects of meal schedule and quantity on displays of problematic behavior. In the first example, self-injury displayed by a toddler with severe developmental delays was maintained by parent attention, but only when he was satiated for food. When he was food deprived, ...
Foster T M - - 1996
Performance of dairy cows responding under concurrent variable-interval variable-interval schedules of food delivery was examined, with results analyzed in terms of the generalized matching equation. In Experiment 1, bias measures indicated that crushed barley was preferred over meatmeal when these foods were available under the alternative schedules. For whole-session data, ...
Elliffe D - - 1996
Three pigeons responded for food reinforcement on multiple variable-interval schedules in which the total consumption of food was entirely determined by the subjects' interaction with the schedules (a closed economy). The finding of overmatching, where response allocation between components is more extreme than the distribution of reinforcers, was reconfirmed. Generalized-matching ...
Mazur J E - - 1996
In three experiments, pigeons chose between alternatives that required the completion of a small ratio schedule early in the trial or a larger ratio schedule later in the trial. Completion of the ratio requirement did not lead to an immediate reinforcer, but simply allowed the events of the trial to ...
Kern L - - 1996
This study compared the relative efficacy of providing simultaneous or delayed reinforcement on food acceptance during meals. The participant was a 7 year-old boy with pervasive developmental disorder and a history of food selectivity. Results indicated that both procedures were effective in increasing acceptance; however, the simultaneous reinforcement procedure produced ...
Cousins M S - - 1996
This experiment was conducted to study the role of nucleus accumbens dopamine in the performance of a novel T-maze cost/benefit procedure. Rats were trained on a T-maze task for food reinforcement. Under one of the test conditions, one arm of the maze contained a high reinforcement density (4 x 45 ...
Ahearn W H - - 1996
We compared two treatment packages involving negative reinforcement contingencies for 3 children with chronic food refusal. One involved physically guiding the child to accept food contingent on noncompliance, whereas the other involved nonremoval of the spoon until the child accepted the presented food. Subsequent to baseline, an alternating treatments comparison ...
Ploog B O - - 1996
Four pigeons responded under autoshaping contingencies in which different conditional stimuli (red or green keylights) were associated with unconditional stimuli of different magnitudes (large or small food pellets) over successive trials within a session. Both topography (beak opening or gape) and strength (rates and latencies of key pecks and gapes) ...
Pitts R C - - 1996
Key pecking by pigeons was maintained on a chained fixed-interval 4-min (12-min for 1 subject) fixed-ratio 1 schedule of food presentation. Attacks toward a restrained and protected conspecific were recorded. In the first experiment, the amount of food presented per interval was manipulated across phases by varying the number of ...
Calef R S - - 1995
24 male rats were randomly assigned into one of three groups. The first group was immediately reinforced with food pellets upon entering a wide goal-box area after running down a straight alley. The second group was reinforced with food pellets 10 sec. after they placed their noses above the goal ...
Case D A - - 1995
Water budget of pigeons was varied to assess the dependence of risk-sensitive preferences upon economic context such as has been reported for energy-budget manipulations with small animals in behavioral ecology research. Fixed- and variable-interval terminal-link water schedules reinforced choice between equal variable-interval initial-link schedules arranged on two pecking keys. While ...
Franklin S R - - 1995
Several dopamine agonists (apomorphine, quinpirole, 7-OH-DPAT, and U-91356A) suppressed locomotor activities of rats exploring a Y-maze, presumably through activation of dopamine autoreceptors. If brief electric shocks were applied to the grid floor during exploration, locomotion was unchanged in control rats, but the locomotor suppression from the dopamine agonists was converted ...
Parker J L JL Department of Anatomy and Cell Biology, University of Toronto, - - 1995
Previous studies have implicated the tegmental pedunculopontine (TPP) nucleus in mediating the rewarding effects of opiates, food, and amphetamine, provided that animals are not in aversive motivational states induced by food--or drug--withdrawal. We wondered if bilateral TPP lesions could block the reinforcing effects of systemic cocaine in a place conditioning ...
Jewett D C - - 1995
The current study demonstrates the ability of neuropeptide Y (NPY) to increase break points under a progressive ratio 1 (PR1) reinforcement schedule. An initial response resulted in delivery of a food reinforcer (45 mg pellet) under the PR1, and an additional response was required for each successive reinforcer. The break ...
Hudzik T J - - 1995
One of the primary undesired effects of anticonvulsant medication is an impairment in cognitive function, such as new learning ability. The purpose of the present study was to compare the effects of remacemide hydrochloride [(+/-)-2-amino-N-(1-methyl-1,2,-diphenylethyl)acetamide monohydrochloride] and FPL 15896AR [(+)-alpha-phenyl-2-pyridine-ethanamide] to a number of anticonvulsant agents on an operant acquisition ...
Jarema K - - 1995
Previous studies have found that defecation increases in rats exposed to intermittent schedules of food delivery. In the present study, food-deprived pigeons were exposed to fixed-time 30-, 60-, 120-, and 240-s schedules of food delivery. For the subjects as a group, significantly more defecation (indexed by fecal weight) occurred under ...
Campbell L S - - 1995
Previous studies examining the relationship between response rate and reinforcement rate on variable-interval schedules (the variable-interval response function) have confounded elapsed session time with within-session changes in food density. The present experiments attempted to manipulate these factors independently and thus isolate their effects on responding. In Experiment 1, 7 rats ...
McSweeney F K - - 1995
Rats pressed keys or levers for water reinforcers delivered by several multiple variable-interval schedules. The programmed rate of reinforcement varied from 15 to 240 reinforcers per hour in different conditions. Responding usually increased and then decreased within experimental sessions. As for food reinforcers, the within-session changes in both lever and ...
Lamas E - - 1995
Food-deprived rats (at 80% of their free-feeding weights) were exposed to a fixed-time 60-s schedule of food-pellet presentation and developed schedule-induced drinking. Lick-dependent signaled delays (10 s) to food presentation led to decreased drinking, which recovered when the signaled delays were discontinued. A major effect of this punishment contingency was ...
Forzano L B - - 1995
Experiment 1 used 6 preschool boys and Experiment 2 used 6 adult women to explore the effects of food preference on humans' choice in self-control paradigms. The boys showed a higher proportion of responses for more delayed, larger reinforcers (a measure of self-control) when those choices resulted in receipt of ...
Green L - - 1995
In three experiments pigeons played (i.e., chose between two colored keys) iterated prisoner's dilemma and other 2 x 2 games (2 participants and 2 options) against response strategies programmed on a computer. Under the prisoner's dilemma pay-off matrix, the birds generally defected (i.e., pecked the color associated with not cooperating) ...
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