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1.
In Experiment 1, rats poisoned following schedule-induced saccharin consumption showed a moderate reduction in the schedule-induced consumption of saccharin. With repeated poisoning, schedule-induced saccharin polydipsia was markedly reduced. Acquisition of conditioned aversion under the schedule-induced procedure was significantly slower than acquisition under water deprivation. In addition, recovery of consumption of the previously poisoned solution during extinction was more rapid under schedule-induced polydipsia. Experiment 2 revealed that schedule-induced polydipsia was less sensitive to suppression by conditioned aversions than a prandial drinking condition in which subjects were equally food deprived but were given a mass feeding instead of spaced pellet deliveries, suggesting that the relative insensitivity of schedule-induced polydipsia to conditioned taste aversions is not simply a function of different levels of food deprivation. This relative insensitivity is offered as a partial basis for the occurrence and maintenance of schedule-induced alcohol polydipsia.  相似文献   

2.
Food-deprived rats that receive intermittent delivery of small amounts of food develop excessive drinking--specifically, schedule-induced polydipsia (SIP). A main characteristic of SIP is its occurrence at the beginning of interfood intervals. The purpose of this study was to demonstrate that SIP can be developed toward the end of interfood intervals, in closer proximity to upcoming than to preceding food delivery. In Experiment 1, two groups were exposed to a fixed-time (FT) 30-sec food schedule with water available during the first or the last 15 sec of each interfood interval. Two additional groups, which had access to water throughout, were exposed to FT 30-sec or FT 15-sec schedules of food presentation. The FT 30-sec group with free access to water developed the highest level of intake; similar and intermediate levels were induced in all the remaining groups. In Experiment 2, three groups of rats were exposed to an FT 90-sec food schedule with water available during the first, the second, or the last 30 sec of each interfood interval. One additional group with access to water throughout was exposed to the FT 90-sec schedule of food presentation. The group with free access to water developed a higher level of consumption than did the other groups, but by the end of training none of the four groups showed statistical differences in polydipsic drinking. Results show that adjunctive drinking can be developed in proximity to upcoming food delivery even with long interfood intervals.  相似文献   

3.
Food-deprived rats were exposed to a schedule in which a brief stimulus was presented approximately once every 60 sec. The first leverpress to occur in the presence of the stimulus always turned it off, and produced a food pellet 50% of the time. When the rats were given concurrent access to water, a running wheel, or both, drinking predominated during intervals initiated by pellet delivery, while running predominated during intervals initiated without food. When allowed to obtain all of their food pellets at the beginning of a session, rats drank less and ran more than when the intermittent schedule was in effect, and most drinking occurred within the first half of the session, while running was distributed throughout the session. Adjunctive drinking and wheel running appear to be functionally different, drinking being schedule-induced and food-bound, running being neither.  相似文献   

4.
In Experiment 1, rats were allowed to acquire either schedule-induced drinking or schedule-induced wood-chewing behavior under a fixed-interval (FI) 60-sec schedule of food reinforcement, following which food was omitted from 20% and then 50% of interreinforcement intervals. Omission of food severely disrupted induced drinking but had relatively little effect on induced wood-chewing. Experiment 2 investigated wood-chewing as a function of reinforcement rate, using a range of FI schedules from 5 to 180 sec in duration. Both the amount of chewing per session and the relative time spent chewing were bitonically related to reinforcement rate. In Experiment 3, schedule-induced chewing that had been acquired under a response-dependent schedule was found to persist under a response-independent schedule. Induced wood-chewing resembles other induced behaviors in important respects, but quantitative differences are also apparent.  相似文献   

5.
In two experiments, the hypothesis that frustration mediates the production of schedule-induced polydipsia was tested. In Experiment I, a group in which reward was reduced from 6 to 2 pellets of food in an operant chamber was found to increase water intake compared to a group maintained at 2 pellets reward. In Experiment II, rats trained to approach food on a partial reinforcement schedule in a runway subsequently showed lower levels of water intake in the operant test for polydipsia than rats given continuous reinforcement during runway training. The results are interpreted as supporting a frustration hypothesis of schedule-induced polydipsia and are discussed within the context of persistence theory.  相似文献   

6.
Animals poisoned following the schedule-induced consumption of saccharin initially continued to drink following spaced pellet deliveries. Neither the initiation of postpellet drinking (i.e., bout, initiation) nor the size and duration of the bouts was effected by the conditioned aversion procedure. With repeated conditioning trials (i.e., repeated pairings of saccharin and LiCl), schedule induced drinking was eventually reduced. The specific components underlying schedule-induced consumption, however, were differentially affected by the aversion training. Specifically, the decrease in schedule-induced drinking was effected primarily by a decrease in licking occurring between 10 and 60 sec after pellet delivery. Bout initiation and licking immediately postpellet (i.e., within the first 10 sec following pellet delivery) were most resistant to suppression and appeared to be responsible for the relative insensitivity of schedule-induced drinking to conditioned taste aversions. The differential effects of taste aversion conditioning on individual components of elicited behavior are discussed.  相似文献   

7.
Food-deprived rats develop polydipsia on an intermittent schedule (fixed time 60 sec) of food pellet delivery, but not on an identical schedule of food powder delivery. This result was demonstrated with separate groups receiving each type of food and was replicated using rats as their own controls. Powdered food not only prevented the development of polydipsia, but it abruptly terminated ongoing polydipsia in rats that were switched from the scheduled delivery of pellets to powder. Ethological analysis of the behavior showed that the rats receiving powder were not engaging excessively in some behavior other than drinking. After discounting several factors, we concluded that the amount of oral activity associated with feeding, which occurred immediately after food delivery, was reciprocally related to the level of drinking.  相似文献   

8.
The effect of wheel running on the level and temporal distribution of schedule-induced polydipsia was examined in 12 food-deprived rats given one food pellet per minute for 1 h. For all rats, wheel running decreased the level of Polydipsie intake. It also decreased licking in all six of the 10-sec postpellet intervals except the first. The degree of reduction in licking was a U-shaped function of the 10-sec postpellet intervals and was generally inversely related to the temporal distribution of running. The temporal distribution data are partially consistent with a temporal competition view of the interactions between schedule-induced polydipsia and wheel running  相似文献   

9.
Rats’ responding was maintained on a random-interval 1-min food schedule. In addition, non-contingent pellets were delivered, independently of the animals’ behavior, at either fixed intervals (Experiment 1) or at random intervals (Experiment 2). As the rate of delivery of the periodic and aperiodic free reinforcers increased, the rate of responding decreased. But these free reinforcers, in addition to having this inhibitory effect, had also a local excitatory effect upon responding: lever-pressing increased to a level above its mean rate following the delivery of a free food pellet. The time course of this behavioral aftereffect of free reinforcers, for both fixed and random intervals, was dependent upon the proportion of the interval between successive free food deliveries. The relation of these results to those obtained with response-contingent reinforcement, free punishment, and in schedule-induced phenomena is discussed.  相似文献   

10.
Four pairs of rats were studied in a yoked control design intended to determine if an interim activity (schedule-induced drinking) was sensitive to operant contingencies. Food was always presented on a fixed-time 30-sec schedule. Additionally, a positive or negative operant contingency was in effect during the first 6 sec of each interval. The positive (drink/food) contingency produced an extra food presentation at the 6th second of an interval if the lead rat drank at least once in the first 6 sec. The negative (no-drink/food) contingency produced an extra food presentation only if the lead rat did not drink in the first 6 sec. Two pairs of rats were first exposed to the positive contingency and then to the negative contingency. Two pairs received training in the reverse order. In drink/food training, all lead rats developed patterns of drinking that produced extra food presentations in most intervals. There were some indications that the positive contingency facilitated early acquisition of drinking, but the yoked rats eventually developed temporal distributions and asymptotic levels of drinking comparable to those that occurred in lead rats. In no-drink/food training, the two lead rats initially exposed to the positive contingency showed high levels of drinking inappropriate to the negative contingency, but the two lead rats initially exposed to the negative contingency showed appropriately low levels of drinking. The latter effects seem attributable to the no-drink/food contingency.  相似文献   

11.
Five rats were exposed to fixed-time food schedules, ranging from 30 to 480 sec. Three rats displayed a postfood pattern of schedule-induced drinking, with short latencies from food delivery to drinking at all interfood interval durations. In contrast, drinking for the other 2 subjects tended to occur at lower overall levels, and drinking bouts frequently began in the middle of the interfood interval, such that the latency from food delivery to drinking increased dramatically as the interfood interval increased. Observation of these 2 subjects revealed that another form of licking-pawgrooming-occurred reliably after food delivery and before drinking bouts. A between subject comparison of the 3 postfood drinkers and the 2 pawgroomers revealed that, in addition to a common topography (repetitive licking), pawgrooming and drinking were similar with respect to their temporal locus, relation to the interfood interval, and extinction baseline levels. These similarities suggest that drinking and pawgrooming are induced by a common mechanism. Cohen, Looney, Campagnoni, and Lawler’s (1985) two-state model of reinforcer-induced motivation provides a useful framework for the interpretation of these results.  相似文献   

12.
Eating was measured in water-deprived rats when water was presented at regular intervals ranging from 30 to 240 sec. The temporal patterning of eating resembled that of schedule-induced behavior in that the probability of eating was high early in the interval and declined in the end of the interval. Additionally, (a) the number of pellets consumed was controlled by relative time in the interwater interval, (b) the pellets consumed per water presentation was inversely related to water rate, and (c) food-ingestion rate was directly related to water rate. These relationships parallel those found with behavior regarded as schedule induced.  相似文献   

13.
Conditioned taste aversions produced a moderate, but transient, suppression of schedule-induced polydipsia. This suppression was greater and longer lasting when rats were offered a choice between water and the previously poisoned solution on the polydipsia baseline. A final experiment demonstrated that taste aversions were more effective in suppressing schedule-induced consumption when superimposed on a developing schedule-induced drinking baseline as opposed to a stable pattern of schedule-induced drinking. It was suggested that schedule-induced polydipsia is insensitive to conditioned taste aversions. This conclusion was discussed in terms of schedule-induced alcohol consumption and its potential as an animal model of alcoholism.  相似文献   

14.
Lashley and Rosellini (1980) have recently suggested that schedule-induced polydipsia (SIP) is determined by the occurrence of absolute periods within schedules of periodic food delivery which are associated with a low probability of food delivery, that is, CS? periods. To assess this hypothesis, SIP was examined in the present experiments under three schedules—fixed time, variable time, and random time (RT)—which differed in probability of occurrence and/or duration (Experiment 1), and under a range of RT schedules in which the CS? period was systematically varied by changing the interpellet interval (Experiment 2). In both experiments, the level and temporal distribution of SIP did not seem to be related to the absolute period associated with the absence of food. Instead, SIP was more systematically related to the average length of the interpellet interval and, therefore, to the average period associated with no food. It was suggested that drinking under intermittent schedules of pellet delivery, that is, SIP, is determined by an average CS? period and not by an absolute period associated with the unavailability of food.  相似文献   

15.
In Experiment 1, 12 rats were exposed to an FT 60 schedule of food reinforcement, followed either by extinction or by a massed-food control condition, in the presence of a wood block. In 9 rats, wood-chewing behavior increased systematically during the FT 60 condition and declined again during extinction or massed food, while the other 3 rats showed virtually no chewing behavior at any stage of the experiment. In Experiment 2, frequency and bout duration of wood-chewing under an FT 60 schedule of food reinforcement declined as body weight increased, in 7 rats. We conclude that wood-chewing qualifies as a schedule-induced behavior, and that it resembles schedule-induced drinking in its dependence on body weight. Unlike drinking, however, induced chewing occupied the middle region of the 60-sec interreinforcement interval, declined markedly within the session, and showed considerable within- and between-subject variability.  相似文献   

16.
In Experiment I, rats which had received six partially reinforced runway acquisition trials, with a reward magnitude of 60 sec access to wet mash on rewarded trials, showed less persistent responding over highly massed extinction trials than subjects which had received the same acquisition schedule but reward magnitudes of either 1 or 10 45-mg pellets. In Experiment II, rats which had received six partially reinforced placements into one compartment of a two-compartment box, with 60 sec access to mash on rewarded placements, jumped a hurdle faster to escape nonreward than subjects which had received the same reward schedule but 10 45-mg pellets on rewarded trials. The data supported a primary frustration analysis for reward-magnitude manipulations within brief partial-reinforcement schedules.  相似文献   

17.
Schedule-induced polydipsia was studied using a behavioral contrast paradigm. Food pellets were delivered to food-deprived rats on a response-independent FT 1-min schedule. Licking on a tube produced water on a MULT FR 10 FR 10, MULT FR 10 EXT, or MIXED FR 10 EXT for three rats (Experiment 1) and on a MULT VI VI, MULT VI EXT, or MIXED VI EXT schedule for three other rats (Experiment 2). On the FR schedules, rats could drink more water by increasing lick rates, but on the VI schedules the amount of drinking was fixed by the schedule parameters and was relatively unaffected by lick rates. Relative to MULT FR FR, positive polydipsia contrast was clearly demonstrated on MULT and MIXED FR EXT; but relative to MULT VI VI, contrast was not demonstrated on MULT and MIXED VI EXT. These data suggest that polydipsia contrast occurs only if increased licking permits increased drinking.  相似文献   

18.
Animals poisoned following exposure to saccharin subsequently avoided the schedule-induced consumption of saccharin. While this suppression was transient for subjects who had access only to the saccharin solution during the free-food presentations, recovery of schedule-induced saccharin consumption was significantly retarded for subjects who had concurrent access to saccharin and a running wheel. It has been suggested that the transient suppression of schedule-induced polydipsia by conditioned taste aversions results from the pellet-induced tendency to drink within the schedule-induced polydipsia procedure. That access to the running wheel reduces schedule-induced polydipsia in general and prolongs the suppression of schedule-induced polydipsia by taste aversions supports this view.  相似文献   

19.
The problem was to determine how rats adjust the times of their lever responses to repeating sequences of interfood intervals. In Experiment 1, rats were trained on an interval schedule of reinforcement with a 12-element Fleshler-Hoffman series with a mean of 60 sec; the order was as follows: ascending, random with repetition, random with replacement, random without replacement. In Experiment 2, rats were trained with a 10-element ascending or descending series (from 20 to 29 sec), and in a ramp procedure in which these intervals increased and then decreased repeatedly. In the ascending, descending, and ramp conditions (but not in the random conditions), postreinforcement pause (PRP) was a function of the interval. PRP was most highly correlated with an interval later in the series. Theories of conditioning and timing based on the averaging of past experience must be modified to account for such anticipatory behavior.  相似文献   

20.
Four food-deprived rats barpressed with food reinforcement on a 1-min fixed-interval schedule in 7-h sessions with water either present or absent. They all became polydipsic, drinking after many pellets early in sessions but after fewer pellets later in sessions. Pellets were secured at near maximum rates for about 3 h. Thereafter, the three heaviest drinkers obtained more food with water than without it. The results indicate that schedule-induced drinking does not continue indefinitely and that it can be adaptive with regard to feeding.  相似文献   

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