Sparing of patterned alternation but not partial reinforcement extinction effect after prenatal chronic exposure to ethanol in infant rats.

The effects of in utero administration of ethanol on single patterned alternation (PA) and the partial reinforcement extinction effect (PREE) were studied in 15-day-old rat pups. This fetal-alcohol treatment had no effect on PA but eliminated the PREE by reducing persistence in extinction after partial reinforcement (PRF) training to its level after continuous reinforcement (CRF) training, which was not affected by the treatment. The results are discussed in terms of prenatal damage to the hippocampus and in relation to an earlier experiment (Lobaugh, Bootin, & Amsel, 1985), which found no effect of infant hippocampal lesions on PA but an elimination of the PREE, which, unlike the fetal-alcohol case, resulted from PRF-like persistence in extinction following CRF training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retention of response persistence in weanling and adolescent rats.

Two experiments (192 Sprague-Dawley rats) examined parameters affecting retention of continuously reinforced (CRF) and partially reinforced (PRF) runway training in weanling and adolescent Ss. In Exp I, weanling Ss were given CRF or PRF training and 12 hrs, 3 days, or 10 days later were given 8 CRF reacquisition trials followed by extinction. In Exp II, weanling and adolescent Ss were given CRF or PRF runway training and extinguished 10 days later following 0, 8, or 24 CRF reacquisition trials. Results suggest that (a) weanlings characteristically display a partial reinforcement extinction effect (PREE) of unusually large magnitude if extinguished within 12 hrs of training, (b) this large-magnitude PREE dissipates within 3 days of training regardless of the number of CRF reacquisition trials preceding extinction, (c) no PREE of any magnitude is seen in weanlings or adolescents following a 10-day interval unless CRF reacquisition trials precede extinction, and (d) retention of the PREE is poor or nonexistent in Ss trained as adolescents and extinguished 10 days later, even with CRF reacquisition preceding extinction. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction of persistence in a within-subject partial reinforcement experiment.

Male albino Wistar rats (N = 96) served as Ss in 2 within-S partial reinforcement experiments, designed to lessen generalization in acquisition as a means of eliminating the generalized partial reinforcement effect in extinction. When the use of a separate-phase mode of training alone proved to be unsuccessful for this purpose, a phase of extinction was interpolated between the continuously and partially reinforced acquisition phases. This manipulation was successful and Ss receiving the training sequence of partial reinforcement-extinction followed by continuous reinforcement-extinction did not show the generalized partial reinforcement effect in the final extinction phase. It is suggested that during the phase of interpolated extinction avoidance responses were counterconditioned to the stimulus complex which included nonreward. (French summary) (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partial reinforcement effects in classical aversive conditioning in rabbits and human beings.

Investigated the partial reinforcement extinction effect (PREE) in classical aversive conditioning. In Exp I the nictitating membrane responses of approximately 120 naive New Zealand rabbits were conditioned at a 250-msec interstimulus interval under continuous reinforcement, partial reinforcement with the unconditioned stimulus (UCS) omitted (Group PO), or partial reinforcement with the UCS delayed to 1,500 msec (Group PD). These 3 groups were factorially extinguished under UCS-omitted, UCS-unpaired, or UCS-delayed extinction regimens. A significant PREE was obtained, but only for PO training and UCS-omitted extinction. Exp II, employing 50 undergraduates in a masked eye blink conditioning task, produced parallel results. A general discrimination view of the classical PREE seems applicable, but one in which neither cognitive factors nor intertrial conditioning of reinforcement aftereffects plays a significant role. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of persistence: immediate and long-term persistence in rats varying in training age between 17 and 65 days

In Experiment 1, six age groups of rats were trained to run an alley for either partial (PRF) or continuous reinforcement (CRF). Training was during a 2-day period starting at six different ages, and extinction was initiated about 12 hr later. There was a clear partial reinforcement extinction effect (PREE) at all ages and, particularly after PRF training, an inverse relationship between resistance to extinction and age. In Experiment 2, retention and durability of persistence as well as immediate persistence were tested following acquisition at three different ages. The immediate extinction tests confirmed the results of Experiment 1. In the delayed extinction tests, greater resistance to extinction following PRF than following CRF was found in all age groups after both the retention and durability manipulations. In neither test was there an effect of age in original acquisition on the magnitude of adult persistence. These experiments confirm earlier findings of remarkable persistence in rats trained and tested at weanling age, show that the persistence is even greater in pre-weanlings, and show that it is retained into young adulthood.     

Resistance to extinction in the goldfish (Carassius auratus).

Examined resistance to extinction of 180 goldfish in a trials-equated alley situation. A reverse partial reinforcement effect (100% vs. 57% reinforcement) was found following brief acquisition training, while a conventional partial reinforcement effect was obtained after extended acquisition training. Extended acquisition training with a partial reinforcement sequence that had N lengths of 3 (an N length is the number of consecutive nonreinforcements before at least 1 reinforced trial) produced greater resistance to extinction than training with a sequence that had N lengths of 1. After brief acquisition training Ss with the shorter N length produced greater resistance to extinction. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retention and durability of persistence acquired by young and infant rats.

Conducted 2 experiments in a runway apparatus with 72 young Holtzman rats. A classic partial reinforcement acquisition effect was obtained in Ss trained from 30 to 45 days of age but not in those trained from 18 to 25 days of age. In an immediate extinction test for half of the Ss, a partial reinforcement extinction effect (PREE) was found in both age groups, but there were differences in the extinction patterns. Following a 45-day retention interval and a continuous reinforcement reacquisition treatment for all groups, the PREE emerged clearly in adult Ss which had not undergone previous extinction. In those Ss which had previously been extinguished the PREE emerged again but was somewhat reduced. Results from the younger Ss suggest that relatively permanent persistence in approach to food can be formed in the days that normally immediately precede and follow weaning in laboratory rats. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Noradrenaline and partial reinforcement in rats.

Lesions of the dorsal noradrenergic bundle produced by 6-hydroxydopamine, which depleted telencephalic noradrenaline by over 95%, were found to produce resistance to extinction in male albino Wistar rats trained on a continuously reinforced schedule for food reward but not to alter the extinction rate after partial reinforcement training. These results confirm the dorsal bundle extinction effect reported previously (S. T. Mason and S. D. Iversen, 1977) but suggest that it is confined to continuously reinforced situations. The pattern of results is consistent with a role for the dorsal bundle in attentional processes but appears to contradict the predictions required if the dorsal bundle were to have a role in frustrative nonreward. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of acquisition training schedule on extinction and reinstatement of cocaine self-administration in male rats.

Partial reinforcement is known to increase resistance to extinction (Rn) relative to training with continuous reinforcement. This phenomenon, referred to as the partial reinforcement extinction effect, is one of the most robust in learning and conditioning studies. Experiment 1 investigated manipulations known to affect the partial reinforcement extinction effect and determined their possible relevance for drug use patterns. Male rats received intravenous cocaine self-administration training under partial reinforcement (FR-10) training or continuous reinforcement (FR-1) conditions with either a low (0.25 mg/kg infusion) or a high cocaine dose (1.00 mg/kg infusion). Animals were placed on an extinction (recurrent nonreward) schedule for 10 days (1-hr sessions) prior to being tested for cue-induced reinstatement (single 2-hr session). Experiment 2 involved acquisition of cocaine self-administration under FR-1 conditions of short training (15 days) or extended training (30 days) with a low dose (0.25 mg/kg infusion) or a medium dose (0.50 mg/kg infusion) of cocaine reward prior to extinction or reinstatement. Experiment 1 showed that rats trained with FR-10-high dose outcomes exhibited greater Rn than the remaining groups. Additionally, FR-10-high dose and FR-10-low dose rats were more likely to return to active drug seeking during the reinstatement test. In Experiment 2, rats trained under FR-1-medium dose conditions were more persistent during extinction following short acquisition training than comparable rats experiencing extended acquisition training. The reinstatement test was conducted following extinction, in which it was observed that overtraining under FR-1-medium dose reward schedules resulted in a decrease in the tendency to return to active drug seeking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance of goldfish (Carassius auratus) in patterned sequences of rewarded and nonrewarded trials.

Studied the performance of 40 goldfish in 4 experiments with patterned sequences of reward (R) and nonreward (N) for responses to a given stimulus (S3). Trials with 2 other, readily discriminable stimuli, in which response to one was always rewarded and response to the 2nd never rewarded, were interpolated in such a way that the outcome of any S3 trial could not be predicted from the events of the immediately preceding trial. The main purpose was to look for control of response to S3 based on memory of N like that found in previous work with pigeons. In Exps I and II, blocks of R and N trials with S3 were programmed, R trials in the 1st half of each session and N in the last half, or N trials in the 1st half and R in the last half. In Exp III, successive acquisition and extinction of response to S3 was studied, with the N-to-R, and R-to-N transitions either within sessions or between sessions. In Exp IV, the effects of partial and consistent reinforcement on extinction of response to S3 were compared. Results are similar in important respects to those for pigeons, as described by P. A. Couvillon et al (see record 1981-07158-001), but different in their failure to demonstrate control of performance by memory of N. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appetitive learning and extinction in 11-day-old rat pups: Effects of various reinforcement conditions.

Studied the acquisition and extinction of approach behavior in 96 11-day-old albino Sprague-Dawley rat pups in 3 experiments. The reinforcement in Exps I & II was 15 sec of nonnutritive suckling on an anesthetized lactating female. In Exp I, detention duration, 0- or 15-sec in the goal box on nonreward (N) trials, was studied in 2 groups whose acquisition training consisted of alternating blocks of rewarded and nonrewarded trials with a short (5-sec) intertrial interval. Exp II combined an examination of the effect of detention length with whether or not the mother was physically present, though inaccessible, on N trials with partially or continuously rewarded groups. Detaining Ss on N trials slowed the rate of extinction when the mother was present but increased the rate of extinction when she was absent. There was no evidence of a partial reinforcement extinction effect in any of the groups. The effectiveness of 6 types of reinforcement on promoting acquisition of approach behavior was assessed in Exp III. Equally good acquisition, but differences in extinction was obtained with an adult conspecific as the reinforcer, independent of sex and suckling, but there was no acquisition of approach responding when a sibling or no conspecific was in the goal box. These data extend earlier findings of appetitive learning and extinction in infant rats. They do not support the view that inhibitory mechanisms are absent in the rat until the 3rd or 4th wk of life. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of acute trimethyltin exposure on appetitive acquisition and extinction performance in the adult rat.

16 adult male Sprague-Dawley rats were given an intragastric infusion of 7 mg/kg of trimethyltin chloride (TMT), and 16 additional Ss (controls) received saline, to investigate TMT's effect on Ss' appetitive acquisition and extinction performance. Ss from each condition were divided into 2 equal groups and trained with either partial or continuous reinforcement (PRF or CRF) in a straight-alley maze 21 days after dosing. The acquisition training phase contained 40 trials (4 trials/day) and was followed by 20 trials of extinction training (4 trials/day). Analyses performed on total speed revealed that TMT Ss performed at lower levels during acquisition than controls, regardless of schedule condition. Also, the rate of resistance to extinction was significantly reduced for TMT Ss compared with that of controls, regardless of the training schedules used during acquisition. A PRF extinction effect was observed for both control and TMT Ss, independent of dose regimen. PRF training occasioned greater persistence during extinction than did CRF training. Findings are discussed in terms of issues relating to TMT-induced hippocampal lesions. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limbic lesions and the energizing, aversive, and inhibitory effects of non-reward in rats.

Tested 30 male albino Wistar rats with bilateral lesions in the amygdala, septum, hippocampus, stria terminalis, and fornix on a multiple reinforcement schedule in which barpressing in one component was associated with VI reinforcement (S+) and the other with extinction (S–). Responses on a 2nd lever turned off S– for 5-sec periods during the extinction component. All groups, with the exception of Ss with amygdaloid lesions exhibited behavioral contrast. Ss with hippocampal or fornical lesions showed greater resistance to extinction. Response rates on the lever that turned off S– were higher after stria terminalis and septal lesions, whereas lower rates were obtained from Ss with amygdaloid lesions. It is concluded that amygdaloid lesions attenuate the energizing and aversive effects of nonreward, septal and stria terminalis lesions increase the aversive effects, and hippocampal and fornical lesions interfere with the inhibitory effects of nonreward. (French summary) (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sparing of patterned alternation but not partial reinforcement effect after infant and adult hippocampal lesions in the rat.

Assessed the effect of hippocampal lesions in patterned (single) alternation (PSA) and the partial reinforcement extinction effect (PREE), the 2 reward-schedule effects that appear earliest in ontogeny. 147 Sprague-Dawley rats received hippocampal or sham lesions or served as unoperated controls. Three groups were tested for each effect: lesion as infant/test as infant; lesion as infant/test as adult; and lesion as adult/test as adult. Hippocampal lesions had no effect on PSA in any of the 3 conditions except for a suggestion that the effect was mildly attenuated in Ss given lesions as infants and tested as adults—Ss were able to discriminate rewarded from nonrewarded trials and to inhibit responding on nonrewarded trials. On the other hand, the PREE was eliminated under all conditions of testing, in each case because of an increase in persistence following continuously reinforced acquisition. Results are discussed in terms of the functional maturation of the hippocampus and a possible dissociation of mechanisms that mediate response suppression in PSA and in the PREE in infant rats. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Noradrenaline and sensory preconditioning in the rat.

Two experiments investigated the effect of noradrenaline (NA) depletion following intraperitoneal administration of the neurotoxin N-2-chloroethyl-N-ethyl-2-bromobenzylamine ({dsp4}[50 mg/kg]) on sensory preconditioning in male Sprague-Dawley rats. For sensory preconditioning, a saccharin taste conditioned stimulus (CS?) and a special type of drinking bottle (noisy bottle) were paired during Phase 1. During Phase 2, the noisy bottle (CS?) was paired with lithium chloride, and during Phase 3 the aversion to saccharin (CS?) was tested in saccharin preference tests. {dsp4} treatment disrupted Ss' ability to form sensory preconditioning, and this effect could not be explained on the basis of enhanced neophobia, stimulus generalization, or a deficit in 1st-order conditioning in {dsp4}-treated Ss. Findings are discussed in relation to issues of associative learning such as contextual control of latent inhibition and extinction. Data suggest that NA-depleted rats fail to form associations between the CS? and CS? during sensory preconditioning and are consisitent with other data from compound conditioning experiments on the functional role of NA in learning and memory. (53 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of successive negative contrast and its dissociation from other paradoxical reward effects in preweanling rats.

Studied the effects of abrupt reductions in reward magnitude (the successive negative contrast—SNC—effect) in Sprague-Dawley rats of various ages and with dry pellet or milk rewards. In Exp I, SNC was shown in 61–68 day olds but not in 17–24 day olds with food reward. Exp II showed strong SNC at 34–35 days and marginal contrast at 25–26 days, again with food reward. With milk reward (Exp III), there was a clear SNC effect at 25–26 days, a slight effect at 20–21 days, but no effect in 16–27 day olds. Results suggest that SNC occurred earlier with milk than with dry food reward. Exp IV repeated the 16–27 day milk-reward condition of Exp III with more highly massed trials. Reduction of reward size reduced performance to the level of an appropriate small-reward control. Finally, Exp V demonstrated a dissociation of SNC and other paradoxical reward effect at 16–27 days of age. The extinction effects of partial reinforcement (PREE), partial delay of reinforcement, and varied magnitude of reward were large and clear. These results are related to earlier work on the ontogeny of SNC in even younger animals and are discussed in relation to an apparent transitional period of the PREE in ontogeny. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence in the absence of primary motivation in the albino rat.

Trained 24 male Holtzman rats under either partial reinforcement (PRF) or continuous reinforcement (CRF). Ss were subsequently pre-fed their daily ration in the form of reward pellets and immediately run in the same task under a CRF schedule. Results reveal that PRF-trained Ss persisted in the satiated state relative to CRF controls. These results, termed the satiation effect, present difficulties to theories of persistence which address only extinction tests. An interpretation utilizing a modification of A. Amsel's (1962) frustration hypothesis is advanced. Implications of this proposal for a general theory of persistence and the methodological advantages of the satiation technique are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence of runway performance after septal lesions in rats.

Assigned 32 male Wistar albino rats to groups receiving bilateral septal lesions or control operations. Septal lesions prevented the partial reinforcement extinction effect after 48 acquisition trials. Septal Ss showed increased resistance to extinction following continuous reinforcement but decreased resistance to extinction following partial reinforcement. Analysis of the acquisition data indicated that the lesions retarded the development of approach-avoidance conflicts associated with reward and nonreward. In a 2nd study, 16 septal and 16 control Ss received 96 acquisition trials. Extended training allowed the development of conflict responses under partial reinforcement, and the Ss with lesions were indistinguishable from controls during extinction. Following continuous reinforcement, septal lesions produced slower extinction of response. It is concluded that the lesions interfered with the development of feedback from frustration, approach-avoidance conflicts, and frustration tolerance. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral and neuroanatomical effects of prenatal, postnatal, or combined exposure to ethanol in weanling rats.

Separate and combined effects of prenatal and postnatal exposure to ethanol on activity, emotionality, learning, and hippocampal neuroanatomy were examined in infant rats. Neonatal rats from mothers that were fed either a liquid ethanol (E) or control (C) diet were artificially reared on either 3% ethanol (E) or isocaloric maltose/dextrin (C). Pups in 4 treatment groups (EE, EC, CE, and CC) were compared. Differences in activity and emotionality were slight. Ethanol affected both the partial reinforcement acquisition effect and the partial reinforcement extinction effect. Hippocampal cell density (compared with Group CC) showed a 12% reduction in CA1 pyramidal cells and an 11% reduction in mature granule cells in Groups EC and EE; the CA4 area (compared with Group CC) was significantly larger after postnatal exposure (Groups CE and EE). Significant positive correlations were found between rate of extinction after partial reinforcement (PRF) training and CA1 pyramidal cell density in Groups CC and CE. A significant negative correlation was found between extinction rate after PRF training and CA4 area in Group EE. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Durability and generalizability of persistence training.

40 male and 40 female college students experienced either partial reinforcement (persistence training) or continuous reinforcement on either of 2 instrumental tasks (finger shuttle or button press) as therapy for failure-induced depression and subsequently were exposed to protracted failure (extinction). Following this initial extinction phase all Ss received continuous reinforcement on a common instrumental task (button press) as therapy and then encountered extinction (consecutive failure trials) for a 2nd time. Results show that increased persistence occasioned by partial-reinforcement therapy was able to survive interpolated periods of extinction and continuous reinforcement; that is, durable persistence training effects were shown. Furthermore, persistence training effects were shown to be generalizable (the persistence advantage associated with partial-reinforcement therapy transferred across topographically different responses), but the generalization process was not a complete one. The results are discussed within the frameworks of frustration theory and alternative cognitive theories. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)