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1.
Subjects in six experimental groups (n = 16 each) received one-trial passive avoidance (PA) training in which shock was delivered upon movement from a white wooden
floor compartment to a black grid compartment. Then fear was extinguished (30 min) in the black compartment. After either
24 or 168 h, all the groups were treated in a room distinctively different from the training room. At each interval, one group
received a shock in an apparatus similar to the conditioning box, another received a shock in a dissimilar apparatus, and
another was placed in a neutral box. A PA test trial in the training apparatus indicated reinstatement of extinguished fear
in all the groups given a postextinction shock except the 24-h dissimilar group. Control groups revealed that the extinction
treatment was effective and that spontaneous recovery was not evident. The results were explained in terms of classical conditioning,
stimulus generalization, and the broadening (flattening) of stimulus generalization gradients with time. 相似文献
2.
Hooded rats received five 1-sec shock presentations of 0.3, 0.5, or 1.0 mA. Activity measures recorded during each 30-sec intershock interval and at various retention intervals (.10, 2.5, and 24 h) following footshock (FS) indicated that (a) 5 sec after FS activity is directly related to shock intensity, while 10–30 sec following FS activity is inversely related to shock intensity; (b) the rate of decline in activity following FS increases with successive shock presentations; (c) activity is greater 10 h after FS than at a 2.5- or 24-h retention interval; and finally (d) shock compartment confinement increased activity and resulted in a substantial alteration in the form of retention curve in the 0.3-mA group but had lesser effects upon the retention curves of the 0.5- and 1.0-mA groups. The data were interpreted as supporting the hypothesis that the “incubation effect” is a result of a decline of the activating effects of FS. 相似文献
3.
Young toads,Xenopus laevis, were trained for dark avoidance in a passive avoidance paradigm using electric shock in a fully automatic training and recording procedure. Dark avoidance was acquired within approximately 30 min and was retained on retesting 24 h later. Comparison of the performance of the toads during training and during retesting was used as an indicator for saving or reinforced retention. Control experiments demonstrated that changes in behavior were due to learning and not to nonassociative effects such as pseudoconditioning, increased sensitization to shock, or acquaintance with the testing apparatus. 相似文献
4.
In the first experiment, rats given a 5-min period of preexposure (simple exploration) to a two-compartment box showed poorer passive avoidance of the compartment where they were subsequently shocked than a control group which was not preexposed to the apparatus. The second experiment involved preexposure to sugared milk (SM), flashing light and loud noise (LN), or simply the apparatus (EC). One group received no exposure to the apparatus (NC). Following one shock trial, the groups were ordered LN > NC > EC > SM from most to least passive avoidance. The results were discussed in the context of latent inhibition and an averaging model of positive and negative events. 相似文献
5.
Three experiments assessed the conditions that potentiate effects of an electroconvulsive shock (ECS) administered 24 h after avoidance training. Stimuli present immediately prior to the ECS were systematically varied. In Experiment 1, which employed a passive avoidance task, the primary determinant of whether the ECS disrupted retention was whether the situational cues present at the time of ECS delivery were those associated with the initial training experience: ECS disrupted performance only when it was administered in the original training apparatus, regardless of whether or not a footshock was presented immediately prior to ECS. In Experiment 2, which employed an active, shuttlebox avoidance task, both the situational cues from the training apparatus and a footshock were necessary to potentiate the disruptive effects of the ECS. Experiment 3 revealed that ECS effects on performance of the active avoidance task can also be potentiated by a combination of apparatus cues and the warning signal used in initial training. These results are interpreted as indicating that informational functions of stimuli present when an ECS is administered are important determinants of the effects of the ECS. 相似文献
6.
Experiment I demonstrated shuttlebox avoidance conditioning using intense white noise as a UCS. Ten rats were given 25 trials a day for 6 days. Escape latencies declined and avoidance responses increased over trial blocks. Experiment II provided support for a functional similarity between shock as a UCS and intense noise as a UCS by demonstrating the Kamin effect following incomplete shuttlebox training to noise. Separate groups of rats were given 25 trials followed by an additional 25 trials either 0, 1, 4, or 24 h later. The U-shaped Kamin effect was evident in the avoidance measure. A similar but inverted U-shaped function was obtained for the escape latency measure. Escape latencies were longer on retraining than on original training at 1 h but not at 0, 4, or 24 h after original training. 相似文献
7.
Retention of a brightness discrimination avoidance task by rats is impaired (Kamin effect) following a 1-h training-to-test interval (TTI), is enhanced after a 3-day TTI (reminiscence, or long-term spontaneous improvement), and is disrupted following a 21-day TTI (long-term forgetting). An exposure to the conditioned stimulus (CS), delivered 5 mm before a 1-h delayed retention test, not only compensated for the performance deficit that corresponds to the Kamin effect, but induced a large improvement in performance similar to that normally obtained after a 3-day TTI. It can be proposed that such cuing may act either by accelerating a natural memory-trace maturation process or by improving the retrievability of the memory trace. Since these possibilities lead to opposite predictions concerning the length of the facilitation induced by cuing, the effect of a pretest exposure to the CS on performance obtained during a 1-h delayed retention test was studied after several cuing-to-test intervals (0, 5, 10, or 20 min). The results, which indicate that cuing transiently enhanced subsequent retention performance, more convincingly support the retrieval hypothesis. The effects of pretest exposure to the CS (which occurred 5 min before testing) were also examined 10 min, 1 h, or 24 h after initial training. The results indicate that the facilitative effect of cuing obtained when retention performance was disrupted shortly after training (1-h TTI) was also obtained after a 24-h retention interval, in the absence of performance disruption. An interpretation of the facilitative effect of a pretest exposure to the CS is proposed, and implications concerning the memory trace are further discussed in relation to the multidimensional hypothesis. 相似文献
8.
Wallace R. McAllister Dorothy E. McAllister Stephen E. Dieter James H. James 《Learning & behavior》1979,7(2):165-173
In Experiment 1, four groups of subjects (n = 16 each) were exposed to the situational stimuli of a shuttlebox apparatus for 4 h. Subsequently, 200 two-way avoidance trials were administered (100/day) with either .3- or 1.6-mA shock and with either small or large reward (presence or absence of visual stimuli following the response). Avoidance performance was directly related to shock intensity on both days and to magnitude of reward on the 2nd day. In Experiment 2, four groups of subjects (n = 24 each) were given 4 h of exposure either to the situational stimuli of the shuttlebox or to a neutral box. Then, 10 two-way avoidance trials were given with 1.6-mA shock. Subsequently, subjects were allowed to escape from one of the shuttlebox compartments to an adjacent safe box. Following preexposure to situational stimuli, avoidance performance was superior whereas escape-from-fear performance was inferior. This latter finding demonstrated that less fear of situational cues was present during avoidance training in the preexposed condition. All of these results support the effective reinforcement theory, an extension of two-factor theory, which emphasizes the importance for avoidance learning of the amount of fear of situational cues present following a response. 相似文献
9.
Retention interval effects are seen in taste-aversion learning when single-element aversions are significantly weaker 24 h after conditioning compared with tests at later intervals. This report contains three experiments which suggest that the source of the increased drinking at the 1-day interval is nonassociative interference produced by the novel conditioning episode. In Experiment 1, a parametric analysis demonstrated that aversion strength increased monotonically over a 30-h period following conditioning, and that by 48 h after conditioning it was stabilized. In Experiment 2, a single US preexposure was used to reduce the novelty of the US prior to conditioning. As a result, animals preexposed to the US had stronger taste aversions than did non-preexposed controls at a 1-day retention interval; however, no differences were seen at a 5-day interval. Experiment 3 investigated whether the counterintuitive outcome of Experiment 2 was due to the summation of environment-illness and taste-illness associations at the 1-day test. The results ruled out the summation argument; the US preexposure did not need to be presented in the conditioning context to strengthen the aversion at the 1-day interval. Collectively, these results suggest that the presentation of a surprising US can interfere with the retrieval of the taste-illness association for a short period after conditioning, and that this contributes to the retention interval effect. 相似文献
10.
Michael L. Platt Elizabeth M. Brannon Tara L. Briese Jeffrey A. French 《Learning & behavior》1996,24(4):384-393
Golden lion tamarins (Leontopithecus rosalia) and Wied’s marmosets (Callithrix kuhli) exhibited adaptive differences in performance on several distinct memory tasks. On both an open-field analogue of a radial arm maze and a spatial delayed matching-to-sample task, the marmosets performed better than the tamarins after short (5-min) retention intervals, but only the tamarins continued to perform above chance after long (24- or 48-h) retention intervals. The marmosets also required less training than the tamarins did to learn a color memory task, but again only the tamarins performed above chance when the retention interval was increased to 24 h. The results of these experiments are consistent with predictions based on knowledge of the feeding ecology of these species in the wild and raise the possibility that they possess different visuospatial memory abilities specialized for tracking the spatial and temporal distribution of their principal foods. 相似文献
11.
John M. Pearce 《Learning & behavior》1978,6(3):341-345
Three experiments examined the relationship between shock magnitude and the rate of acquisition of a passive avoidance response. Experiment 1 indicated that the use of a relatively large magnitude of shock can disrupt learning to remain on a platform in the center of an open field to avoid shock. The inferior learning of the group trained with high shock was replicated in Experiment 2, which also demonstrated that avoidance learning can occur rapidly with this level of shock if the platform is located in the corner of the apparatus. To explain this, it was proposed that thigmotactic behavior is responsible for the disruption in avoidance behavior when training is conducted in the center with high-magnitude shock. Finally, Experiment 3, essentially a replication of Experiment 1 except that the platform was placed in the corner of the test compartment, demonstrated a direct relationship between shock magnitude and passive avoidance learning. The results are seen as being consistent with accounts which maintain that avoidance learning can be influenced by the occurrence of species-specific defense reactions. 相似文献
12.
In a conditioned suppression experiment, rats received a single, massed session of conditioning in which one backward conditioned inhibitory stimulus (CS-) followed shocks that were signaled by a visual cue, and a second backward CS-followed shocks that were unsignaled. Conditioning was preceded by a preexposure phase in which some groups of rats were preexposed to unsignaled shock, while others were not preexposed and remained in the experimental apparatus in the absence of shock. The groups were further distinguished by whether US preexposure and conditioning occurred in the same or different contexts, and by whether conditioning began immediately or after a 24-h rest period in the home cage. Although the conditioning itself was effective in establishing the visual cue as a conditioned excitor in the nonpreexposed groups, it was not effective in establishing the two backward cues as reliable inhibitors with either signaled or unsignaled USs. After 210 US preexposures, however, the same conditioning sessions did yield conditioned inhibition to both CS-s. A 24-h rest period in the home cage reduced the magnitude of, but did not completely abolish, the facilitative effect of US preexposure on inhibitory conditioning. Other tests demonstrated that US preexposure had retarded excitatory conditioning to the visual cue. This interference with excitatory conditioning was unchanged in magnitude after the 24-h rest period. The facilitative effect of US preexposure on backward inhibitory conditioning, and the interference effect on excitatory conditioning, were both eliminated by a change in context between US preexposure and conditioning. These observations encourage predominantly associative accounts of the effects, but allow for a small nonassociative habituation component. 相似文献
13.
Anthony Dickinson 《Learning & behavior》1976,4(4):416-420
In Experiment 1, four groups of rats received conditioned suppression training in which a tone was reinforced with shock. If the tone had been previously paired with response-independent food, aversive conditioning was slightly facilitated by comparison to control groups preexposed either to the tone randomly associated with food or to the tone and food unpaired. However, by comparison to a control which was not preexposed to the tone, animals receiving prior pairings of the tone and food showed retarded aversive conditioning. Experiment 2 replicated the facilitation in aversive conditioning after the tone had been paired with food relative to the random control condition and demonstrated that this difference occurred even if the tone and background stimuli continued to be associated with response-independent food during aversive conditioning. This result suggests that pairing a stimulus with an appetitive reinforcer reduces the retardation of aversive conditioning produced by stimulus preexposure. 相似文献
14.
Howard M. Reid 《Learning & behavior》1987,15(4):375-378
SJL/J mice underwent one-trial passive avoidance training, followed immediately by either electroconvulsive shock (ES) or sound-induced seizure. Testing of the passive avoidance response occurred 72 h later. It was found that an ES-induced seizure, but not a sound-induced seizure, caused amnesia for the passive avoidance learning. 相似文献
15.
In Experiment 1, hungry rats received 30 rewarded runway trials and then either extinction trials followed by retention tests or just retention tests. Different groups were tested after retention intervals of 1 min, 1, 3, or 24 h, or 30 days. Retention of extinction training was a nonmonotonic, cubic function of time for the early portion of the response chain, with good retention at 1 min and 3 h and little retention at 1 h, 24 h, or 30 days. In the latter portions of the response chain, retention of extinction decreased monotonically with time. Retention following reward-only training varied little in time, though slight losses occurred after 30 days. Experiments 2–3 differed from Experiment 1 in imposing nonchoice discrimination training (reward vs. nonreward) instead of extinction following 30 rewarded trials. After different time intervals (.017, .75, 1.25, 3, and 24 h in Experiment 1; and .017, 1, and 3 h in Experiment 2), retention tests revealed poorest discrimination at intermediate intervals in the initial portion of the response chain, i.e., a Kamin effect appeared. The deficit seemed the result of a loss of response suppression to the cue that signaled nonreward. In latter segments of the response chain, a Kamin effect tended not to appear. Implications for a number of observations and theoretical views are noted. 相似文献
16.
Mice were trained in a one-trial passive avoidance task and retested 2 min, 5 min, 10 min, 30 min, or 24 h later. A biphasic time-response curve was obtained with art initial increase to 5 min, a subsequent decrease, and another increase to 24 h. Other groups of Ss were administered electroconvulsive shock (ECS) 2, 5, 10, or 30 min after training and retested 24 h later. The response curve shape of the ECS-treated groups was found to correspond to that concerning the different retest times, suggesting a negative correlation between ECS amnesic effect and the strength of the conditioned response at the time of ECS administration. The inadequacy of the hypotheses, according to which ECS interferes with a gradual monotonic process, to explain ECS amnesic effect is discussed. 相似文献
17.
The effects of flavor preexposure and retention interval were assessed in 6- and 12-day-old rats. Conditioned aversions to a flavor appeared at both ages. The conditioning of the younger pups was unaffected by conditioned stimulus (CS) preexposure and was not evident after a 10-day retention interval. For the 12-day-old rats, preexposure to either the flavor CS or a different flavor attenuated aversion strength when the rats were tested soon after conditioning. Other 12-day-old rats that were tested 10 days after conditioning also expressed substantial aversions, but with a retention interval of this length, the aversions were equivalent for animals preexposed to the CS and those not preexposed before conditioning. This loss of the CS-preexposure effect over a long interval, which has also been observed in adult rats, identifies the locus of this effect as postacquisition and perhaps at the stage of memory retrieval. 相似文献
18.
Deprivation of REM sleep for 2 h immediately following shuttlebox avoidance training produced deficient retention at 24 h after initial training. REM deprivation beginning 2 h after training had no effect. REM sleep appears to be involved in consolidation of this learning. 相似文献
19.
Rick Richardson Tania Q. Duffield Glynis K. Bailey R. Frederick Westbrook 《Learning & behavior》1999,27(4):399-415
Rats were shocked in the black but not the white compartment of a shuttlebox and then exposed to the black compartment in the absence of the shock unconditioned stimulus (US) to extinguish fear responses (passive avoidance). In five experiments, rats were then shocked in a reinstatement context (distinctively different from the shuttlebox) to determine the conditions that reinstate extinguished fear responding to the black compartment. Rats shocked immediately upon exposure to the reinstatement chamber failed to show either reinstatement of avoidance of the black compartment or fear responses (freezing) when tested in the reinstatement chamber. In contrast, rats shocked 30 sec after exposure to the reinstatement chamber exhibited both reinstatement of avoidance of the black compartment and freezing responses in the reinstatement chamber (Experiment 1). Rats shocked after 30 sec of exposure to the reinstatement chamber but then exposed to that chamber in the absence of shock failed to exhibit reinstatement of the avoidance response and did not freeze when tested in the reinstatement chamber (Experiment 2). Rats exposed to a signaled shock in the reinstatement chamber and then exposed to that chamber in the absence of shock also failed to exhibit reinstatement of the avoidance response (Experiment 5). These rats showed fear responses to the signal but not to the reinstatement chamber. Finally, rats exposed for some time (20 min) to the reinstatement chamber before shock exhibited reinstatement of the avoidance response but failed to freeze when tested in the reinstatement chamber (Experiments 3 and 4). These results are discussed in terms of the contextual conditioning (Bouton, 1994) and the US representation (Rescorla, 1979) accounts of postextinction reinstatement. 相似文献
20.
Animals given electroconvulsive shock (ECS) following active avoidance training were found to exhibit poor retention of the active avoidance response. However, this deficit was alleviated if the animals received an extinction trial for active avoidance prior to retention testing. That the trial was an extinction trial was demonstrated by the fact that exposure to the trial decremented the performance of animals not given ECS after learning. The implications of these findings for explanations of retrograde amnesia are discussed. 相似文献