Immediate effect of septal area damage on DRL performance in the rat.

Investigated the immediate and long-term effects of septal area lesions on performance on a differential reinforcement of low rates (DRL) 10-sec schedule. Ss were 43 male albino rats. Septal area lesions produced immediate disruption of DRL responding in unanesthetized Ss, but cingulate area lesions or sham treatments did not. The induction of septal seizures without lesions produced only minimal disruption. For the first few testing sessions, Ss tested 7 days after receiving septal area lesions were indistinguishable in DRL performance from those tested immediately; the former, however, showed poorer recovery. It is concluded that neural or other changes requiring time to develop postoperatively are not essential to the disruption of DRL performance, but they may impede behavioral recovery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collateral behaviors and the DRL deficit of rats with septal lesions.

Trained a total of 31 male Long-Evans hooded normal and septally-lesioned rats to lever press for food on a DRL 20-sec schedule in either a conventional operant chamber or 1 containing wood blocks and cardboard strips. The DRL behavior of normals trained in modified chambers was most efficient, and that of Ss with septal lesions trained in conventional chambers was least efficient. After 35 hr. of training, normals tested in conventional chambers and Ss with septal lesions tested in modified chambers did not differ significantly. Ss chewed the blocks and cardboard, and prevention of these collateral behaviors reduced DRL efficiency. Results show that colalteral behaviors facilitate the development of efficient DRL behavior and indicate that the DRL deficit of rats with septal lesions can be modified. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observing response acquisition: Preference for unpredictable appetitive rewards obtained under conditions predicted by DMOD.

To investigate the preference for unpredictable rewards predicted by the present author and J. T. Daly's (see record 1983-20275-001) modification, known as the DMOD model, of R. A. Rescorla and A. R. Wagner's (1972) previous model of reinforcement, the present author conducted 5 E-maze experiments with 144 male Holtzman rats. In Exps I–V, Ss were given a choice between receiving reward and nonreward in a situation in which stimuli were correlated with reward outcome (predictable situation) vs a situation in which the stimuli were uncorrelated with reward outcome (unpredictable situation). Preference for the unpredictable situation occurred under the following conditions: small (1 37-mg pellet) immediate rewards, small delayed (15-sec) rewards when the cues correlated with reward outcome were absent during the delay interval, large (15 pellets) immediate rewards when a difficult discrimination was required, and when the stimulus predicting nonreward was present at the choice point. Preference for the predictable situation was strongest if reinforcement was delayed and large or if the stimulus predicting reward was present at the choice point. A weaker preference for the predictable situation occurred if reinforcement was immediate, large, and required a simple discrimination or if reinforcement was large and delayed and the cues that correlated with reward outcome were absent during the delay interval. Findings support the predictions of the DMOD model of appetitive learning. (33 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

DRL performance, extinction, and secondary reinforcement: Role of appetitive value of food in mice with septal lesions.

Conducted 5 experiments with a total of 116 B6D2F-sub-1/J mice. Normal Ss and Ss with septal lesions were trained on a DRL 8-sec schedule for food reinforcement varying in incentive value. Dilution of diet increased the number of reinforcements received by Ss with septal lesions. In Exps II and III the effects of septal lesions on resistance to extinction after continuous reinforcement training and the strength of secondary reinforcement were investigated. Changes in reinforcement value modified the septal lesion effects in both cases. All 3 experiments demonstrated the alteration of the septal lesion effect through a change in the appetitive value of the reinforcement. Results suggest that one of the mechanisms by which septal lesions impair DRL performance is an enhancement of reinforcing properties of food. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental analysis of behavioral dysfunction in rats with septal lesions.

At 7 days of age, 48 male Long-Evans hooded rats received lesions of the septal nuclei or control operations. Ss then received 30 hrs of training on a DRL 20-sec schedule for 1 hr/day beginning at either 27 or 96 days of age. At 126 days of age, all Ss received 10 additional training sessions. After operant testing, all Ss received 10 additional training sessions. After operant testing, all Ss were tested on spontaneous alternation, spatial reversal, and passive avoidance. Results indicate that on a DRL 20-sec schedule Ss that received lesions of the septum neonatally and were tested at different ages performed in a similar manner. Approximately 50% of the Ss with lesions of the septal nuclei reached efficiency levels comparable with those of normal controls. When tested for retention, these efficient Ss still performed similarly to normal Ss. Ss with septal lesions were facilitated in the acquisition of a spatial habit, were deficient in spatial habit reversal, were less likely to demonstrate spontaneous alternation, and were deficient in passive avoidance. It is concluded that neonatal lesions of the septal nuclei produce permanent behavioral impairments on a diversity of measures and that, although juvenile animals with limbic system damage often manifest behaviors different from adult Ss, the difference is not evident during operant testing (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of neonatal septal lesions on DRL performance in adulthood.

Reports 2 experiments on the influence of neonatal septal lesions on responding of 75 Long-Evans hooded rats trained on a DRL schedule in adulthood. Rats given septal lesions at 1 or 7 days after birth emitted a significantly higher number of responses and earned fewer reinforcements than did those given control electrode insertions. Thus, the inefficient performance on the DRL schedule, often observed after septal lesions in adulthood, does not depend upon the age of the S at the time of the lesion. Furthermore, operant training given at an early age (25-45 days) to Ss with neonatal septal damage did not facilitate performance when they were retrained in adulthood. In short, septal lesions at any age lead to permanent impairments of performance on a DRL 20-sec schedule. (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)     

The effects of reward contingency and performance feedback on intrinsic motivation.

93 high school students were offered performance or task-contingent rewards or no reward for doing hidden-figures puzzles. Ss offered performance-contingent rewards all received positive feedback concerning performance, and half the Ss in task-contingent and no-reward conditions received the same positive feedback. Performance-contingent rewards were found to undermine intrinsic motivation more than task-contingent ones, which produced decrements relative to control conditions of no reward, supporting E. Deci's (1972, 1975) control model. Positive feedback enhanced intrinsic motivation; this effect was independent of reward effects. A recall measure indicated that Ss receiving performance-contingent rewards remembered fewer performance-irrelevant details about the task, suggesting that rewards may affect the process of task involvement as well as its motivational outcomes. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exposure to rewards and the delay of gratification.

Gave 111 children aged 6, 7, 8, and 9 yrs old a choice between an immediate reward and a larger, delayed reward. Half of the Ss in each age group saw the rewards before choosing, while the other half did not. Exposure to the rewards led to more choices of delayed reward for 7 yr olds. The 6 yr olds predominantly chose immediate rewards regardless of exposure, while the 8 and 9 yr olds predominantly chose the delayed reward regardless of exposure. 2 explanations are offered for the results for the 7 yr olds. In one, the results are attributed to the effect of exposure on value and/or expectancy of the delayed reward. In the other, it is suggested that exposure orients attention to the value, rather than the immediacy, of the alternatives. In this view, delay of gratification in young children reflects a form of decentration. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suppressive and enhancing effects of footshock on food-reinforced operant responding following septal lesions in rats.

Measured effect of septal lesions on suppression of an intermittently food-reinforced lever press by contingent and noncontingent footshock, using a total of 48 experimentally naive male hooded Lister rats in 2 experiments. Ss with septal damage maintained higher response rates than did intact Ss under both contingent and noncontingent shock. Furthermore, the difference in suppression produced by the contingent and noncontingent conditions was approximately the same for the experimental Ss and controls. In Exp II performance was measured during counter-conditioning in which the correlation between contingent shock and positive reinforcement was varied. Ss with septal lesions responded at higher rates than did controls. When only reinforced responses were punished, this lesion-induced elevation represented an increase above baseline performance without punishment. This finding suggests that the effect of septal damage on appetitive instrumental performance cannot be due solely to a deficit in response inhibition. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delay of gratification in psychopathic and nonpsychopathic offenders.

Delay of gratification is a prototypical measure of self-control that merits systematic investigation in psychopaths. White male prisoners were provided with repeated opportunities to select an immediate response with uncertain reward or a delayed response with a higher rate of reward under 1 of 3 incentive conditions. Psychopaths' performance depended on their level of trait anxiety and incentive condition: Whereas low-anxious psychopaths were relatively unwilling to delay when omission of expected rewards also incurred monetary punishments, they displayed relative superior performance when the task involved rewards only. Findings complement those for passive avoidance learning in psychopaths and suggest that inhibitory self-control in low-anxious psychopaths is somewhat impaired under conditions involving a combination of monetary rewards and punishments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol demand, delayed reward discounting, and craving in relation to drinking and alcohol use disorders.

A behavioral economic approach to alcohol use disorders (AUDs) emphasizes both individual and environmental determinants of alcohol use. The current study examined individual differences in alcohol demand (i.e., motivation for alcohol under escalating conditions of price) and delayed reward discounting (i.e., preference for immediate small rewards compared to delayed larger rewards) in 61 heavy drinkers (62% with an AUD). In addition, based on theoretical accounts that emphasize the role of craving in reward valuation and preferences for immediate rewards, craving for alcohol was also examined in relation to these behavioral economic variables and the alcohol-related variables. Intensity of alcohol demand and delayed reward discounting were significantly associated with AUD symptoms, but not with quantitative measures of alcohol use, and were also moderately correlated with each other. Likewise, craving was significantly associated with AUD symptoms, but not with alcohol use, and was also significantly correlated with both intensity of demand and delayed reward discounting. These findings further emphasize the relevance of behavioral economic indices of motivation to AUDs and the potential importance of craving for alcohol in this relationship. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal dissociation of limbic lesion effects on shuttle box avoidance in rats.

In a study with a total of 57 male albino Holtzman-derived rats, Ss with septal or hippocampal lesions showed facilitated acquisition of a shuttle box avoidance response compared to normal controls. Ss with septal lesions were also highly resistant to extinction compared with normal Ss. When the same lesion effects were examined in hypophysectomized Ss, the Ss with septal lesions continued to show facilitated performance, and Ss with hippocampal lesions performed no differently than nonoperated controls. These findings are consistent with the hypothesis that the facilitated avoidance performance found in rats with hippocampal lesions is attributable to lesion-induced changes in hypophyseal activity, but similar changes induced by septal lesions are not. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rewards and adolescent health behavior.

Observed 363 male and 369 female 7th-grade adolescents' use of a fluoride rinse over 2 school years. The rinse habit tended to end when reward contingencies were withdrawn. Although participation was higher with a saturated schedule of reward contingencies in effect, the comparison partial schedule of rewards showed less immediate attrition when the reward contingencies were withdrawn. Other findings include higher participation levels for girls compared to boys and for urban compared to suburban students. Self-management instruction, a strategy intended to compensate for the withdrawal of tangible rewards, worked temporarily among urban Ss but at the same time resulted in lower levels of postreward rinsing among suburban Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pretraining effects on performance of rats with hippocampal lesions.

Investigated the role of pretraining factors in the overresponding observed on differential-reinforcement-of-low-rate (DRL) schedules following hippocampal lesions. 24 Long-Evans hooded rats divided into unoperated Ss and Ss with large or small hippocampal lesions were given 10 or 20 days of continuous reinforcement (CRF) pretraining before exposure to a DRL 20-sec schedule. Either large lesions or extended CRF pretraining resulted in only a transient elevation in response rates, while the unique combination of a large lesion and extended pretraining was required for persistent overresponding on DRL. It is concluded that the overresponding produced by hippocampal damage is not solely a function of loss of hippocampal tissue but depends upon unique training conditions for its appearance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multivariate approach to the analysis of genetic and septal lesion effects on maze performance in mice.

Reports univariate and multivariate analyses concerning spatial discrimination behavior of Binghamton heterogeneous (HET), C57BL/6J, and RF/J mice that had received either septal lesions or control surgery (N?=?80). In acquisition of an appetitively motivated T-maze task, lesions impaired HET but improved RF performance relative to their respective controls. When Ss with lesions were reversed on a spatial discrimination acquired in a 17°C water maze, their performance was worse than control Ss; the magnitude of the deficit was strain-specific. Measures of reactivity to handling suggested that HET and RF Ss with lesions were more reactive than their controls; there was no such difference in C57 Ss. Multivariate approaches broadly corroborated the importance of complex Gene?×?Environment interactions that mold experience and thus behavior. They appeared to give some potentially important insights into the differential "behavioral profiles" of Ss with lesions and control Ss of the 3 genotypes; for instance, reactivity to handling and repeated error measurements were important variables in discriminating among the groups in both learning tasks. Thus, multivariate techniques should be considered as useful, additional tools for the development and evaluation of explanatory theories regarding functions of CNS regions. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cued DRL training: Effects on the permanence of lesion-induced overresponding.

Attempted to determine the degree to which lesions in the septum and anatomically related structures result in the presence and/or permanence of overresponding on a DRL 20-sec schedule. Male Long-Evans hooded rats were given 15 days of training to determine the presence or absence of overresponding. Ss that overresponded were divided into 2 groups, with one receiving 15 days of cued DRL training and the other receiving 15 days of regular DRL training. Overresponding occurred in 60 Ss following lesions in septum, hippocampus, medialis dorsalis, and ventral thalamus pars dorsalis. While in effect, cued DRL facilitated performance in 8 controls and in operated Ss but did not facilitate performance when removed in septals. Exposure to the cued DRL allowed hippocampals to reduce responding and increase the frequency of obtained reinforcements. Lesions in medialis dorsalis and ventral thalamus led to an overresponding that disappeared with prolonged regular DRL training. Cued DRL training actually functioned as a time-out from DRL training. Variations in the permanence of the overresponding symptom according to lesion locus preclude identification of the lesion-induced dysfunction based solely on the presence or absence of overresponding. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of consistency of reward during runway training on subsequent discrimination performance in rats.

Describes 2 experiments with male albino Holtzman rats (N = 64). In Exp. I, Ss were trained under partial (PR) or continuous (CR) reward in a gray or striped runway and were then trained on a simultaneous stripe-orientation discrimination. PR caused a decrement in discrimination performance after training in the striped runway but had no effect after training in the gray runway. In Exp. II, Ss received PR, CR, or no training in a runway with stripe cues on the floor of the runway varying randomly in orientation. All Ss were then trained on a simultaneous compound-cues discrimination with orientation and width of stripes relevant. After reaching criterion each S was given single-dimension tests on each dimension. PR Ss performed worse on orientation tests but not on width tests. Results are interpreted as supporting stimulus-analyzer theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationships between performance and satisfaction under contingent and noncontingent reward systems.

Investigated relationships between performance and satisfaction in 2 samples of female telephone company workers under a contingent (i.e., pay based on piece rates and promotions based on performance) and a noncontingent (i.e., rewards based on seniority) reward system. Performance levels were similar under the 2 systems but were related to satisfaction with the work itself, pay, and promotions for the contingent Ss and to satisfaction with interpersonal factors, pay, and work for the noncontingent Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reward discounting as a measure of impulsive behavior in a psychiatric outpatient population.

Impulsivity has been operationalized as a choice of an immediate smaller reward over a larger delayed or uncertain reward. This study examined a procedure that measures reward preference under these contingencies in psychiatric outpatients considered either at a high or low risk for engaging in impulsive behavior depending on their psychiatric diagnoses. The participants' rates of delay and uncertainty reward discounting were compared with their performances on a behavioral inhibition task and responses on a self-report personality impulsivity measure. The high-risk participants discounted delayed rewards more sharply and scored higher on the self-report impulsivity measure relative to the low-risk participants. Delay and uncertainty discounting were modestly correlated, but no other relationships were found between the other measures. Results from this study indicate that delay-discounting tasks may be sensitive to at least one form of impulsive behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)