Continuous Reinforcement Schedule Research Articles

Acute stress persistently alters instrumental motivation without affecting appetitive Pavlovian conditioning, extinction, or contextual renewal

In two experiments, we adapted the stress-enhanced fear learning approach to evaluate the persistent effects of acute stress on appetitive learning and motivation in adult male Long Evans rats. In Experiment 1, we found that exposure to a battery of footshocks in one context had no effect on the acquisition, extinction, or contextual renewal of an appetitive Pavlovian discrimination in different contexts. However, when rats were subsequently trained to respond on a progressive ratio instrumental schedule, rats with a history of shock showed lower response rates and progressive ratio break points. Extinction of the shock-associated context had little effect on progressive ratio responding. In Experiment 2, we replicated this instrumental responding deficit with a continuous reinforcement schedule when the Pavlovian phases did not intervene in the time between shock and instrumental testing. Our findings here demonstrate that highly stressful acute experiences produce long-lasting deficits in instrumental motivation for food in male rats.

Instrumental learning and behavioral persistence in children with attention-deficit/hyperactivity-disorder: does reinforcement frequency matter?

Prominent theoretical accounts of attention-deficit/hyperactivity-disorder (ADHD) hypothesize that reinforcement learning deficits underlie symptoms of ADHD. The Dynamic Developmental Theory and the Dopamine Transfer Deficit hypothesis assume impairments in both the acquisition and extinction of behavior, especially when learning occurs under partial (non-continuous) reinforcement, and subsequently the Partial Reinforcement Extinction Effect (PREE). Few studies have evaluated instrumental learning in ADHD and the results are inconsistent. The current study investigates instrumental learning under partial and continuous reinforcement schedules and subsequent behavioral persistence when reinforcement is withheld (extinction) in children with and without ADHD. Large well-defined samples of children with ADHD (n = 93) and typically developing (TD) children (n = 73) completed a simple instrumental learning task. The children completed acquisition under continuous (100%) or partial (20%) reinforcement, followed by a 4-min extinction phase. Two-way (diagnosis by condition) ANOVAs evaluated responses needed to reach the learning criterion during acquisition, and target and total responses during extinction. Children with ADHD required more trials to reach criterion compared to TD children under both continuous and partial reinforcement. After partial reinforcement, children with ADHD executed fewer target responses during extinction than TD children. Children with ADHD executed more responses than TD children during extinction, irrespective of learning condition. The findings demonstrate general difficulties in instrumental learning in ADHD, that is, slower learning irrespective of reinforcement schedule. They also show faster extinction following learning under partial reinforcement in those with ADHD, that is, a diminished PREE. Children with ADHD executed more responses during extinction. Results are theoretically important, with clinical implications for understanding and managing learning difficulties in those with ADHD, as they suggest poorer reinforcement learning and lower behavioral persistence.

Spatial organization of rat’s behavior in a situation with three optional lever-pressing responses under continuous and fixed-interval schedules of food

We assessed spatiotemporal distribution of behavior as a function of the spatial and temporal arrangement of food delivery. Eight food-deprived rats were exposed in an extended experimental chamber to a continuous reinforcement schedule (CRf) or to a fixed interval (FI) 30 s, with three levers contiguous to food dispenser or placed on separate panels. Responses on any of the levers were equally operative on the ongoing schedule. All rats moved mainly near to dispenser and levers when these were contiguous, under both, CRf and FI schedules, although distribution of responses on different levers was more variant under FI than under CRf. With separate levers, rats traveled through a larger area of the experimental space, especially under FI. Distribution of responses showed more variation under FI than under CRf schedule. Under FI, response patterns consisted in a post-meal pause followed by an acceleration towards the next food. Findings are discussed in the context of studies in which have been reported inconsistent patterns under FI schedules when are manipulated the number of operanda, dispensers, and their locations. It is highlighted the relevance of continuous analysis of rats’ displacement, to account for the configuration of response patterns observed in this study.

O ESTUDO DA PUNIÇÃO COM O JATO DE AR QUENTE: EFEITO DE DIFERENTES HISTÓRIAS DE REFORÇAMENTO

Uma das variáveis que tem influência sobre os efeitos de contingências punitivas é a história de reforçamento. Estudos com choque elétrico demonstram que esquemas de reforçamento contínuo produzem menor resistência à punição, do que esquemas de reforçamento intermitentes. O objetivo desse estudo foi verificar o efeito de um estímulo punidor alternativo - o jato de ar quente (JAQ) - apresentado de acordo com um esquema FR1, sobre a frequência de respostas operantes fortalecidas por diferentes histórias de reforçamento. Seis ratos foram expostos a diferentes histórias de reforçamento durante oito sessões (reforçamento contínuo, razão variável e intervalo variável). Em seguida, os animais passaram por seis sessões em que cada resposta de pressão à barra produzia um JAQ e uma gota de água. Por fim, os animais passaram por seis sessões de recondicionamento, com os mesmos esquemas utilizados na fase de fortalecimento. Durante as sessões de punição, todos sujeitos, independente da história de reforçamento apresentaram total supressão do responder. Quando a punição foi descontinuada todos sujeitos retornaram aos níveis prévios de resposta compatíveis com suas respectivas histórias de reforçamento, os sujeitos do grupo de reforçamento contínuo, contudo, levaram mais tempo para recuperar as taxas de respostas. Limitações metodológicas que comprometeram as conclusões do estudo são discutidas no intuito de aperfeiçoamento.Palavras-chave: punição; história de reforçamento; jato de ar quente; controle aversivo.

Analysis of Families’ Perceptions on Reinforcement usage for Teaching Daily Life Skills to Children with Mild Intellectual Disabilities

In this study, it was aimed to find out if families of children with mild intellectual disability use reinforcement in teaching daily living skills, what kind of reinforcements and reinforcement schedules they use and to learn if they found it effective. This study was based on qualitative research method. The study group of this study consists of 48 families, who have children with mild intellectual disabilities. The research data were obtained from interviews with families via the interview form. To analyze the data, content analysis technique was used. According to the results of the study, consciously or unconsciously families use reinforcements in teaching daily living skills. All types of reinforcements appeared to be used by families but only continuous, variable ratio and interval ratio reinforcement schedules have been found to be used. Reinforcement was used by the families at all age groups, and the families determine the reinforcement with regard to child’s condition and needs and their material and spiritual conditions. One of the most striking results of the study was that families did not have education and elementary school graduates used reinforcements and found it quite useful.

連続強化スケジュール,間欠強化スケジュール,消去がハトのキーつつき反応の位置次元および距離次元における行動変動性に及ぼす効果(特集号 行動変動性の実験研究とその応用可能性22巻2号追加論文)

連続強化スケジュール,間欠強化スケジュール,消去がハトのキーつつき反応の位置次元および距離次元における行動変動性に及ぼす効果(特集号 行動変動性の実験研究とその応用可能性22巻2号追加論文)

Variability and resistance to change of different response positions in response sequences emitted under continuous and lag reinforcement schedules

ABSTRACTThis experiment examined resistance to change of the different response positions of three-response sequences (left/middle/right button presses) exhibited by a group of children when contingencies were shifted from continuous reinforcement to a lag or yoked reinforcement schedule. A backward progression of extinction for the three-response sequences was observed for all subjects under the lag schedule, suggesting that the role of extinction should be reconsidered as an explanation for increased variability observed under lag schedules. We suggest that variability may be, at least partly, explained by the documented effects of responses undergoing extinction rather than characterize variability as an operant dimension that can be reinforced per se.

Conditional Use of a Request for Assistance: Considering Generalization

Individuals with autism spectrum disorder (ASD) frequently exhibit generalization errors, but many instructional programs fail to address this deficit. Generalization errors encompass when the learner should extend the use of a newly taught behavior to other contexts but does not (under-generalization), as well as when he or she should not use the newly established behavior in new contexts but does (over-generalization). This study was designed to evaluate the generalization errors of a preschooler with ASD. Following an intervention in which the participant was taught to request assistance with difficult tasks using a continuous reinforcement schedule, generalization gradients across levels of task difficulty were implemented to examine patterns of generalization. Initial results showed over-generalization of assistance requests and corresponding reductions in independent (the absence of any instructional prompts) task completion across all levels of task difficulty. A final phase involving competing schedules of reinforcement for assistance requests and independent work with video modeling led to improved conditional use of assistance requests. Implications for teaching conditional use of assistance requests are discussed.

Classroom Reinforcement Schedules and Their Effectiveness in Selected Kenyan Primary Schools

The purpose of the study was to determine Classroom Reinforcement Schedules and Their Effectiveness in Selected Kenyan Primary Schools. The study employed a Mixed Methods design in which both quantitative and qualitative data were collected. The target population teachers and pupils from public primary schools. Data was collected by using questionnaires and interview schedules. Quantitative data was analyzed using inferential statistics while Qualitative data was analyzed by using the thematic and content analysis. The study reported on the use of praise, tangible items such as games and money were also moderately often used by the teachers. The participants also used both Continuous reinforcement and partial reinforcement schedules. The study recommends that, schools should enhance token economy programs which have long term effect. Moreover, teachers should deepen their knowledge on token economy programs for academic success. DOI: 10.5901/jesr.2015.v5n3p41

Teaching discriminated social approaches to individuals with Angelman syndrome.

Angelman syndrome is a neurogenetic disorder characterized by intellectual and developmental disability. Common behavioral characteristics of this disorder include a heightened interest in social interactions and frequent bids to initiate interaction. These bids can be problematic, for instance, when a child attempts to hug strangers in public places. The current study evaluated a discrimination training program to teach 3 boys with Angelman syndrome to discriminate appropriate from inappropriate times to initiate interactions. During baseline, we alternated periods in which attention was delivered following social initiations on a continuous reinforcement schedule with periods in which initiations were placed on extinction. We then implemented discrimination training by presenting a salient discriminative stimulus, prompting the occurrence of initiations, and providing reinforcement during reinforcement periods and withdrawing the stimulus during extinction periods. This resulted in discriminated approaches for each of the 3 participants; these results were replicated across caregivers and extended to the participants' homes.

Nocebo Hyperalgesia, Partial Reinforcement, and Extinction

Many studies have found evidence of conditioning-induced nocebo hyperalgesia. However, these studies have exclusively involved continuous reinforcement (CRF) schedules. Thus, it is currently unknown whether nocebo hyperalgesia can result after partial reinforcement (PRF). We tested this using electrodermal pain stimulation in healthy volunteers. Undergraduates (N = 135) received nocebo treatment under the guise of a hyperalgesic. Participants were randomly allocated to CRF, PRF, or control (no conditioning). Conditioning involved surreptitiously increasing pain stimulation on nocebo trials relative to control trials. During training, the CRF group always had the nocebo paired with the surreptitious pain increase, whereas the PRF group experienced the increase on only 62.5% of nocebo trials. In the test phase, pain stimulation was equivalent across nocebo and control trials. PRF was sufficient to induce nocebo hyperalgesia; however, this was weaker than CRF. Nocebo hyperalgesia failed to extinguish irrespective of the training schedule. Additional assessment of expectancies indicated strong concordance between expectancy and nocebo hyperalgesia. Overall, these findings suggest that once established, nocebo hyperalgesia may be difficult to disrupt. PRF may be a novel method of reducing the intensity of nocebo hyperalgesia in the clinic, which may be particularly important given its persistence. PerspectiveThis study provides novel evidence that partial reinforcement results in weaker nocebo hyperalgesia than continuous reinforcement and that nocebo hyperalgesia fails to extinguish, irrespective of the training schedule. As a result, partial reinforcement may serve as a method for reducing the intensity of nocebo hyperalgesia in the clinic.

Calorie seeking, but not hedonic response, contributes to hyperphagia in a mouse model for Prader-Willi syndrome.

Prader–Willi syndrome (PWS) is a neurodevelopmental disorder caused by deletion or inactivation of paternally expressed imprinted genes on human chromosome 15q11‐q13, the most recognised feature of which is hyperphagia. This is thought to arise as a consequence of abnormalities in both the physiological drive for food and the rewarding properties of food. Although a number of mouse models for PWS exist, the underlying variables dictating maladaptive feeding remain unknown. Here, feeding behaviour in a mouse model in which the imprinting centre (IC) of the syntenic PWS interval has been deleted (PWS ICdel mice) is characterised. It is demonstrated that PWS ICdel mice show hyperghrelinaemia and increased consumption of food both following overnight fasting and when made more palatable with sucrose. However, hyperphagia in PWS ICdel mice was not accompanied by any changes in reactivity to the hedonic properties of palatable food (sucrose or saccharin), as measured by lick‐cluster size. Nevertheless, overall consumption by PWS ICdel mice for non‐caloric saccharin in the licking test was significantly reduced. Combined with converging findings from a continuous reinforcement schedule, these data indicate that PWS ICdel mice show a marked heightened sensitivity to the calorific value of food. Overall, these data indicate that any impact of the rewarding properties of food on the hyperphagia seen in PWS ICdel mice is driven primarily by calorie content and is unlikely to involve hedonic processes. This has important implications for understanding the neural systems underlying the feeding phenotype of PWS and the contribution of imprinted genes to abnormal feeding behaviour more generally.

A FUNCTIONAL ANALYSIS OF BEHAVIOR IN THE BALLOON ANALOGUE TASK

In the balloon analogue task, a continuous schedule of positive reinforcement and a random ratio schedule of punishment for “pump” responses operate simultaneously, along with the opportunity to terminate each trial and avoid an impending punishing stimulus. In this study, the functional properties of game points and point losses were analyzed in three groups of college students (N=92) by varying the density of balloon explosions throughout the 30-balloon session. The within-session changes in density of explosions produced immediate systematic adjustments in pump responses per balloon. The results showed that 1) the number of pumps per balloon is sensitive to the local probability of explosions; 2) the suppression brought on by explosions depends on the temporal distance to the last explosion and the number of consecutive explosions; 3) suppression appears to be non-linear, with stronger effects as the local probability of explosions increases; and, 4) within limits, points without assigned extrinsic value may serve as reinforcers in the balloon analogue environment for populations with a history of game playing. Given these findings, a valuable strategy for future research may be to study differential reactivity to wins and losses as a proximal determinant of total scores that is amenable to experimental analysis.

An assessment of fixed interval timing in free-flying honey bees (Apis mellifera ligustica): an analysis of individual performance.

Interval timing is a key element of foraging theory, models of predator avoidance, and competitive interactions. Although interval timing is well documented in vertebrate species, it is virtually unstudied in invertebrates. In the present experiment, we used free-flying honey bees (Apis mellifera ligustica) as a model for timing behaviors. Subjects were trained to enter a hole in an automated artificial flower to receive a nectar reinforcer (i.e. reward). Responses were continuously reinforced prior to exposure to either a fixed interval (FI) 15-sec, FI 30-sec, FI 60-sec, or FI 120-sec reinforcement schedule. We measured response rate and post-reinforcement pause within each fixed interval trial between reinforcers. Honey bees responded at higher frequencies earlier in the fixed interval suggesting subject responding did not come under traditional forms of temporal control. Response rates were lower during FI conditions compared to performance on continuous reinforcement schedules, and responding was more resistant to extinction when previously reinforced on FI schedules. However, no “scalloped” or “break-and-run” patterns of group or individual responses reinforced on FI schedules were observed; no traditional evidence of temporal control was found. Finally, longer FI schedules eventually caused all subjects to cease returning to the operant chamber indicating subjects did not tolerate the longer FI schedules.

Behavioural and neurochemical assessment of salvinorin A abuse potential in the rat

Salvinorin A is a recreational drug derived from Salvia divinorum, a sage species long used as an entheogen. While salvinorin A has potent hallucinogenic properties, its abuse potential has not been assessed consistently in controlled behavioural and neurochemical studies in rodents. This study aimed to assess salvinorin A abuse potential by measuring its capacity to establish and maintain self-administration behaviour and to modify dopamine (DA) levels in the nucleus accumbens (NAcc) of rats. Male Lister Hooded (LH) and Sprague-Dawley (SD) rats were allowed to self-administer salvinorin A (0.5 or 1.0 μg/kg/infusion) intravenously 2 h/day for 20 days under a continuous schedule of reinforcement and lever pressing as operandum. LH rats discriminated between the active and inactive levers but did not reach the acquisition criterion for stable self-administration (≥12 active responses vs ≤5 inactive responses for at least 5 consecutive days). SD rats discriminated between the two levers at the lower dose only but, like LH rats, never acquired stable self-administration behaviour. Systemic salvinorin A increased extracellular DA in the NAcc shell of both LH (at ≥40 μg/kg) and SD rats (at ≥5 μg/kg), but injection into the ventral tegmental area (VTA) induced no significant change in NAcc DA concentration in LH rats and only brief elevations in SD rats. Salvinorin A differs from other commonly abused compounds since although it affects accumbal dopamine transmission, yet it is unable, at least at the tested doses, to sustain stable intravenous self-administration behaviour.

Association between increased behavioral persistence and stereotypy in the pet dog

The aim of the present study was to evaluate whether dogs that exhibit stereotypy also show higher behavioral persistence in an extinction-learning task. Thirteen pet dogs with stereotypy and 13 breed-matched control dogs were assessed on a resistance to extinction test. Each dog was trained for 40 trials using a food reinforcer to nose-touch the experimenter's hand on a continuous reinforcement schedule. After acquisition, the dogs entered an extinction phase, during which food was no longer delivered. The numbers of nose-touches as well as inter-response times during this phase were recorded. A linear regression found that stereotypy status (t=−2.46, P=.027) and breed type (t=2.44, P=.023) were significant predictors of the number of responses in extinction. Dogs with stereotypy responded more in extinction than control dogs. The mean number of responses was 13.4 (SD=14.7) in the control group and 26.0 (SD=15.3) in the stereotypy group. These results suggest a link between previous laboratory and zoo animal findings on the neurophysiology of stereotypy and the pet dog population. They also have implications for the use of extinction procedures to reduce stereotypic behaviors in pet dogs, as these dogs show enhanced resistance to extinction.

A Novel Procedure for Evaluating the Reinforcing Properties of Tastants in Laboratory Rats: Operant Intraoral Self-administration

This paper describes a novel method for studying the bio-behavioral basis of addiction to food. This method combines the surgical component of taste reactivity with the behavioral aspects of operant self-administration of drugs. Under very brief general anaesthesia, rats are implanted with an intraoral (IO) cannula that allows delivery of test solutions directly in the oral cavity. Animals are then tested in operant self-administration chambers whereby they can press a lever to receive IO infusions of test solutions. IO self-administration has several advantages over experimental procedures that involve drinking a solution from a spout or operant responding for solid pellets or solutions delivered in a receptacle. Here, we show that IO self-administration can be employed to study self-administration of high fructose corn syrup (HFCS). Rats were first tested for self-administration on a progressive ratio (PR) schedule, which assesses the maximum amount of operant behavior that will be emitted for different concentrations of HFCS (i.e. 8%, 25%, and 50%). Following this test, rats self-administered these concentrations on a continuous schedule of reinforcement (i.e. one infusion for each lever press) for 10 consecutive days (1 session/day; each lasting 3 hr), and then they were retested on the PR schedule. On the continuous reinforcement schedule, rats took fewer infusions of higher concentrations, although the lowest concentration of HFCS (8%) maintained more variable self-administration. Furthermore, the PR tests revealed that 8% had lower reinforcing value than 25% and 50%. These results indicate that IO self-administration can be employed to study acquisition and maintenance of responding for sweet solutions. The sensitivity of the operant response to differences in concentration and schedule of reinforcement makes IO self-administration an ideal procedure to investigate the neurobiology of voluntary intake of sweets.

The effect of early‐life stress on memory systems supporting instrumental behavior

People experiencing early-life stress (ELS) exhibit increased incidence of behaviors that lead to addiction and obesity as adults. Many of these behaviors may be viewed as resulting from an overreliance on habits as opposed to goal-directed instrumental behavior. This increased habitization may result from alterations in the interactions between dorsolateral striatum-dependent and hippocampus-dependent learning systems. As an initial examination of this idea, we investigated the effect of ELS on instrumental learning and extinction. In Experiment 1, we examined the effect of ELS in two groups of people, one trained on a continuous reinforcement schedule and one trained on a partial reinforcement schedule. We found that people who experienced ELS had a diminished effect of the partial reinforcement schedule on extinction. In Experiment 2, we again manipulated reinforcement schedule and also challenged declarative memory by requiring subjects to perform a concurrent task. We found that the declarative challenge did not affect extinction responding in the non-ELS group. In a moderate-ELS group, we observed a diminished sensitivity to the reinforcement schedule during extinction only under divided attention. In the high-ELS group, we observed a reduced sensitivity to reinforcement schedule even in the absence of the declarative memory challenge, consistent with Experiment 1. Our results suggest that ELS reduces the tendency to use declarative, hippocampus-dependent memory in instrumental tasks in favor of habits. ELS may affect hippocampal development, thus altering the interaction between memory systems and potentially contributing to poor health outcomes.

Attenuation of cocaine and heroin seeking by μ-opioid receptor antagonism

RationaleEvidence has implicated the endogenous opioids, in particular μ-opioid receptors, in emotional behavior and regulation of reward circuits, especially in the context of heroin addiction and hedonic responses to ingestive rewards. The μ-opioid receptor antagonist naltrexone (NTX) has been reported to be effective in preventing relapse to alcoholism and in reducing alcohol and cocaine craving during abstinence.ObjectivesThe aim of the present experiments was to investigate the effects of a novel selective μ-opioid receptor antagonist GSK1521498 on cocaine and heroin seeking and the primary reinforcement of drug self-administration behavior.MethodsRats were first trained to self-administer cocaine or heroin and then to seek the drugs over prolonged periods of time under a second-order schedule of reinforcement, in which responding is maintained by contingent presentation of a drug-associated conditioned reinforcer. On a stable baseline, animals were treated with either GSK1521498 (0.1, 1, 3 mg/kg; IP) or NTX (0.1, 1, 3 mg/kg; SC) before each test session.ResultsCocaine seeking was dose-dependently decreased following GSK1521498 treatment. However, the same treatment had no effect on cocaine self-administration under a continuous reinforcement schedule. Treatment with NTX had a less pronounced but similar effect. GSK1521498, but not NTX, dose-dependently reduced heroin seeking both before and after infusion of the drug although both increased heroin self-administration under continuous reinforcement.ConclusionsThese data suggest that GSK1521498, by reducing opioid receptor signaling at the μ-opioid receptor, may have therapeutic potential to reduce the propensity to seek cocaine or heroin and, additionally, to diminish the consequence of an initial relapse to heroin taking.

Amygdala-Prefrontal Synchronization Underlies Resistance to Extinction of Aversive Memories

Emotional memories can persist for a lifetime but can also undergo extinction. Although we know about the mechanisms involved in expression and extinction, we know very little about the mechanisms that determine whether a specific memory would persist or not. Here, we use partial reinforcement extinction effect (PREE) to explore the neural mechanisms that differentiate persistent from labile memories. We recorded the simultaneous activity of neurons in the amygdala and the dorsal anterior cingulate cortex (dACC) while monkeys engaged in tone-odor aversive conditioning. We report that under continuous reinforcement schedule (ConS), activity in the amygdala precedes behavioral response, whereas under partial schedule (ParS), dACC activity precedes it. Moreover, we find that ParS induced cross-regional pairwise correlations throughout the entire acquisition session, and their magnitude and precision predicted the later resistance to extinction. Our results suggest that memory persistence depends on distributed representations and, specifically, resistance to extinction of aversive memories is maintained by correlated amygdala-dACC activity.