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At least 1,045 records · Page 58Linked to original sources
PubMed1996

T-maze and food reinforcement: an inexpensive drug discrimination procedure.

The present study provides a detailed description of a novel drug discrimination procedure employing a T-maze and food reinforcement. Three groups of rats (n = 5) were trained to run one of the two arms of the maze after the i.g. administration of either 1.0, 1.5 or 2.0 g/kg ethanol (chosen as training drug) and the opposite arm after administration of water. Only correct trials were rewarded. All the rats learned the discrimination task. Substitution tests with different doses of ethanol in all the three groups and with the non-competitive NMDA antagonist, dizocilpine (MK-801), in the 2.0 g/kg ethanol-trained group provided a pharmacological validation of the paradigm. Advantages and disadvantages of this procedure are discussed.

Animals↗
PubMed1982

Immediate and delayed reinforcement on WISC-R performance for mentally retarded students.

Thirty white mentally retarded children were administered the WISC-R under one of three conditions: standardized testing conditions, standardized plus immediate reinforcement, standardized plus delayed reinforcement. One reinforcement group earned tokens immediately after each correct response and the other reinforcement group received their earned tokens halfway through and at the end of the IQ test. Both reinforcement groups exchanged their tokens for a variety of backup reinforcers at the halfway point and at the end of the test. Both the immediate and delayed reinforcement groups showed significantly better performance than the standardized testing group, although the two reinforcement groups did not differ from one another. Half of the children in each of the groups that earned tokens scored above the mentally impaired range while only one child in the standardized testing group scored above the mentally impaired level. Implications for the use of intelligence tests for mentally retarded students are discussed.

Child↗
PubMed1981

6-Hydroxydopamine and radiofrequency lesions of the lateral entorhinal cortex facilitate an operant appetitive conditioning task in mice.

The entorhinal cortex seems heterogeneous as dopaminergic terminals are present only in the anterior part of the lateral entorhinal cortex. In order to clarify the interaction of this cortex with the hippocampus in memory processes, the effects of either 6-hydroxydopamine or radiofrequency bilateral lesions were compared. Both lesions enhance the retention of a Skinner task with continuous reinforcement schedule. Involvement of dopamine in memory processes is discussed.

Animals↗
PubMed1984

Effect of ovarian hormones on conflict behavior.

We injected ovariectomized female rats with estrogen and progesterone. Some of the injection regimens used are known to induce estrus, while other do not. The effects of these treatments on operant behavior were evaluated. Operant behavior was maintained under a reinforcement schedule, one segment of which involved experimentally induced conflict. Such behaviors previously have been shown to be modified by anti-anxiety drugs. Those hormone treatments effective in inducing estrus had behavioral effects similar to the effects observed for established anti-anxiety agents. Hormone-injection regimens not capable of inducing estrus were without effect on operant behavior. Our findings suggest that the reproductive cycles of female rats are associated with behavioral changes which may be indicative of changing anxiety levels mediated in part by changing titers of ovarian hormones. We suggest that the evaluation of hormonal influences on operant behaviors sensitive to tranquilizers should be a useful model system for studying possible mechanisms underlying emotional changes associated with reproductive cycles.

Animals↗
PubMed1986

Corticosterone, free fatty acid and glucose responses of rats to footshock, fear, novel stimuli and instrumental reinforcement.

Rats were subjected to sessions of footshock, fear stimuli and instrumental reinforcement to assess responses of blood corticosterone, free fatty acids (FFA) and glucose. The corticosterone response to fearful situations exhibited a stimulus generalization decrement, thus demonstrating a contribution of Pavlovian classical conditioning to the activity of the hypothalamo-pituitary-adrenal system. Corticosterone levels were shown to decrease during operant sessions with large water reinforcements, while FFA and glucose levels were increasing, thus dissociating these stress measures. FFA responses to intermittent, intense footshock were found to be quadratic; blood levels of FFA increased within 10 min, decreased by 40 min, and then showed the increase with 80-min long sessions previously reported in the literature. This pattern of response was not influenced by prior food deprivation or different methods of sampling blood. Blood levels of FFA increased generally to novel/fearful situations and instrumental reinforcement sessions, which were stimulus situations less stressful than the footshock sessions. Glucose increases occurred to footshock and instrumental reinforcement sessions under some conditions, depending more than corticosterone and FFA on prior food deprivation and blood sampling method.

Animals↗
PubMed1992

Alcohol expectancies, social and environmental cues as determinants of drinking and perceived reinforcement.

Increasing evidence suggests that outcome expectancies and environmental cues interact to influence post-drinking behaviors. Using an experimental methodology in a simulated social drinking setting, this research tested the potential influence of expectations for the effects of drinking, environmental cues, and beverage content on ad lib consumption and post-drinking self-perception. Eighty-eight moderate to heavy-drinking males were randomly assigned to one of eight experimental conditions in which beverage content (alcohol or placebo), social environment (friendly or unfriendly), and physical environment (simulated bar or residence) were varied. Subjects were further divided into high and low groups on three outcome expectancy factors. Unaffected by environmental cues, beverage self-administration increased when subjects strongly expected behavioral impairment from drinking but received placebo beverage. Post-drinking reports of disinhibition increased in response to friendly social cues but were not affected by beverage content or amount. Results therefore suggest that individual's beliefs about the effects of drinking influence the amounts of beverage they consume, whereas social cues more greatly affect post-drinking self-perception.

Adult↗
PubMed1981

Intragastric drug self-administration by rats exposed successively to morphine and ethanol.

Male Sprague-Dawley rats were implanted with intragastric cannulas for self-administration of drug solutions by bar-pressing on a continuous reinforcement schedule in 10-hour daily sessions. Similar levels of responding were observed for doses per infusion of 3.0 mg/kg morphine sulfate and 25 mg/kg ethanol in separate groups of rats. When rats that showed self-administration of a morphine solution over a 5-day period were than given access instead to ethanol for 5 days, the number of infusions taken did not deviate significantly between the two periods. However, rats selected from a small minority that failed to take morphine under these conditions also failed to manifest ethanol self-administration behavior. The data can be seen to support a possible concurrence or similarity between innate factors determining acceptance or rejection of morphine and ethanol as objects of self-administration behavior.

Alcoholism↗
PubMed1988

Brain self-stimulation, locomotor activity and tissue concentrations of ethanol in male rats.

These studies were aimed at correlating the effects of ethanol on operant behavior and on locomotor activity with its distribution in selected tissues in the body. One group of male rats was trained on a continuous reinforcement schedule for intracranial self-stimulation (ICSS) with electrodes in the lateral hypothalamus. Another group was studied in a locomotor activity apparatus, and both groups were given ethanol intraperitoneally over the dose-range 0.3-1.7 g/kg. Urine was collected 15 min and 60 min after ethanol administration and samples of blood, brain, heart, lung, liver, muscle and testis were obtained at both time points. Depressions of ICSS and of locomotor activity occurred, and these changes in behavior were correlated with increasing concentrations of ethanol in blood, urine and tissue. Thus, the disrupting effects of ethanol on behavior which occurred shortly after its acute administration were closely linked to its concentrations throughout the body.

Animals↗
PubMed1990

Desipramine effects on cocaine self-administration by rhesus monkeys.

The effects of desipramine treatment (0.56-10.0 mg/kg per day) on cocaine self-administration were compared to saline treatment in five rhesus monkeys. Cocaine (0.050 or 0.100 mg/kg per inj) and food (1 g banana pellets) self-administration were maintained on an FR 4 (VR 16:S) reinforcement schedule. Desipramine (or an equal volume saline control solution) was infused over 1 h each day through the second lumen of an intravenous catheter. After 5 days of baseline saline treatment, seven doses of desipramine each were administered for 5 days in an ascending order. Cocaine self-administration increased (P less than 0.01) or remained equivalent to base-line levels in 4 of 5 subjects during the first 15 days of desipramine treatment (0.56 to 1.78 mg/kg per day). Three monkeys continued to self-administer cocaine equivalent to or significantly above base-line levels (P less than 0.01) during days 16-30 of desipramine treatment (3.2-7.86 mg/kg per day). The highest desipramine dose (10 mg/kg per day) significantly suppressed cocaine self-administration in only one of these three monkeys (P less than 0.01). Desipramine treatment (3.2-10.0 mg/kg per day) suppressed cocaine self-administration (P less than 0.01) without a concomitant suppression of food-maintained responding in one of five subjects. A generalized suppression of both cocaine and food-maintained responding (P less than 0.01) during desipramine treatment occurred in one monkey that took the highest base-line levels of cocaine (6.3 +/- 1.03 mg/kg per day). Food-maintained responding remained equivalent to or significantly above (P less than 0.01) base-line levels in four of five monkeys during desipramine treatment. A transient decrease in food self-administration at desipramine doses of 1.78-5.62 mg/kg per day occurred in one monkey (P less than 0.01). Thirty days of desipramine treatment at the highest doses (5.62, 7.86 and 10.0 mg/kg per day for 10 days each) also did not suppress cocaine self-administration in a monkey that took an average of 4 mg/kg per day of cocaine during saline base-line treatment. These primate data are concordant with the extant clinical literature on the inconsistent effects of desipramine treatment; i.e., both stimulation of cocaine use and inconsistent or incomplete attenuation of cocaine abuse during desipramine maintenance have been reported.

Animals↗
PubMed1991

Reinforcing breath carbon monoxide reductions in chronic obstructive pulmonary disease.

Chronic Obstructive Pulmonary Disease (COPD) usually results from tobacco smoking. Smoking cessation slows COPD's progression, but few have studied anti-smoking treatments in COPD. In 3-month trials we paid lottery tickets during daily home visits to still-smoking COPD patients for reductions in breath carbon monoxide (CO), a measure of smoke intake. In our first protocol experimental patients received 0-3 tickets per day, depending upon the extent of CO reduction below pre-treatment baselines; yoked controls received the same number of tickets, but not contingent on CO. The protocol produced no change. In a second study patients were assigned a post-baseline quit-date, received nicotine gum, and were paid up to 5 tickets per night, but only for CO less than 10 parts per million (ppm). CO fell sharply as the intervention began, but gradually rose again. A third protocol added special reinforcement schedules for those who did not quit or relapsed (up to 20 tickets per night for CO less than 10 ppm). Daily CO concentrations fell from 27.1 parts per million (baseline mean) to 12.7 (intervention mean), but rapid increases followed the intervention. Few patients stopped smoking, but CO and cigarettes used per day significantly fell during Studies 2 and 3. Post-hoc analysis suggested only a small effect from gum.

Breath Tests↗
PubMed1987

Sensory reinforcement of head turning with nonambulatory, profoundly mentally retarded persons.

Two experiments examined the reinforcing value of response contingent sensory events consisting of combinations of visual, auditory, and vibratory stimulation. Ten nonambulatory, profoundly mentally retarded individuals participated in these studies. Four different stimulus combinations were required to achieve operant conditioning of head turning responses in 6 participants. These sensory reinforcers included 5-s simultaneous presentations of picture, music, and vibration (N = 2), picture and music (N = 2), picture and vibration (N = 1), and picture alone (N = 1). These results indicate that systematically varying a multimodal sensory event is a fruitful procedure for identifying positive reinforcers for nonambulatory, profoundly mentally retarded persons.

Adolescent↗
PubMedDate not supplied

Automated behavioral procedures for infant monkeys.

A method is described for testing infant monkeys on a variety of operant tasks as soon as they can self-feed, typically within the first week of life. Each infant was housed during the 16-21-hour experimental session in a cage to which operant behavioral equipment was attached. Computer control of the experimental contingencies and data acquisition allowed a relatively large number of monkeys to be tested simultaneously, as well as detailed analysis of response parameters. Infant monkeys are capable of learning a number of tasks that assess learning and memory, including visual discrimination and reversal, simultaneous discrimination, and spatial and nonspatial matching to sample. Infant monkeys also perform like older animals on intermittent schedules of reinforcement. The long experimental sessions allowed determination of feeding pattern over the course of the night. Analyses of these variables have proved sensitive to the effects of developmental exposure to neurotoxicants such as lead and caffeine.

Animals↗
PubMedDate not supplied

Neurobehavioral toxicity of methanol reflected by operant running.

Eleven Long-Evans male rats were trained to respond for food delivery by running in wheels under a Fixed Ratio = FR 20 schedule of reinforcement. Each 360 degrees rotation counted as a single response. Three food pellets were delivered for each reinforcement. The wheels, which provided transverse rods to be gripped by the rats, were specifically designed to reflect motor deficits produced by neurotoxicants. Each animal received two replicates of three different doses of methanol (50% in water): 1.0, 2.0, and 3.0 g/kg by gavage. The sequence for each animal was determined by a counterbalanced design. Gavage was followed by admitting the animal to the running wheel compartment 10 min later. Running wheel sessions lasted for 1 hour daily and were conducted 6 days/week. Statistical analyses showed insignificant differences between water and no-treatment control days, indicating no effect of the gavage procedure. However, a dose-effect relationship between methanol dose and responses per session proved statistically significant and linear (p < 0.0001) down to a dose equivalent to 10% of the LD50. In addition, detailed analyses of intervals between successive rotations (IRTs) indicated a displacement of the distribution toward longer intervals (decreased velocities) with increasing dose. The absence of a corresponding rise in the incidence of long pauses suggested that impaired coordination, reduced endurance, or their combination, rather than nonspecific variables, accounted for these results.

Animals↗
PubMedDate not supplied

Bitertanol, a triazole fungicide, increases operant responding but not motor activity.

Several recent reports indicate that triadimefon, a triazole fungicide, has effects on behavior that are similar to those of psychomotor stimulants. For example, triadimefon increases overall fixed-interval (FI) response rate, disrupts FI response patterning, increases motor activity, and produces stereotypies at high doses. The present study was designed to determine whether similar behavioral effects on FI performance and motor activity could be produced by another triazole fungicide, bitertanol. The effects of bitertanol (10-300 mg/kg, IP) were determined in rats on performance maintained under a multiple FI 1-min FI 5-min schedule of reinforcement. Intermediate doses of bitertanol increased response rates and disrupted response patterning in both FI components. A second experiment determined the effects of the same doses of bitertanol on motor activity. In contrast to its effects on operant responding, bitertanol did not increase motor activity at any of the doses tested. These findings indicate that the behavioral similarities between bitertanol and triadimefon are limited and that a dissociation exists between biteranol's effects on operant performance and motor activity.

Animals↗
PubMed2003

The role of prelimbic cortex in instrumental conditioning.

Numerous studies have implicated human and primate prefrontal cortex in the ability to hold and manipulate goal or outcome-related information in working memory to guide the performance of forthcoming actions. Here we report that cell-body lesions of prelimbic cortex impair the ability of rats to select an action based on previously encoded action-outcome associations. Rats were food deprived and trained to press two levers, one delivering food pellets and the other a sucrose solution. All rats acquired the lever-press response although the initial acquisition in the prelimbic rats was significantly slower than in sham controls. Furthermore, whereas in sham-lesioned rats, post-training devaluation of one of the two outcomes using a specific satiety procedure produced a selective reduction in performance on the lever that in training delivered the prefed outcome, prelimbic rats failed to show a selective devaluation effect and appeared to reduce performance on both levers non-selectively. Importantly, this impairment only emerged in extinction; in subsequent experiments it was found that, when a specific action-outcome association was cued either by presentation of the outcome itself or by presenting a stimulus previously paired with the outcome, rats demonstrated an ability to select the associated action. These results suggest that action-outcome encoding may be intact in prelimbic rats and that the lesion impaired their ability to retain this learning in working memory in order to establish a course of action. Alternatively, the lesion may have altered the relative contribution of action-outcome and outcome-action associations to instrumental performance. On this account, prelimbic lesions affect action-outcome encoding but leave outcome-action associations intact providing the basis for outcome-mediated initiation of an action sufficient, perhaps, to support acquisition and performance in the lesioned rats.

Animals↗