The primary goal of the present study was to determine the economic relationship between heroin and social reinforcement in rats: are they substitutes, independents, or complements? In Experiment 1, one group of rats was given a budget of responses that they could allocate between heroin and social reinforcement offered at various combinations of prices. A second group chose between two levers that each resulted in social reinforcement at varying prices when pressed. There was no relationship between the relative allocation of responses between heroin and social reinforcement and changes in their relative prices, indicating that these reinforcers are best viewed as independents.
View Article and Find Full Text PDFIncreased reinforcer motivation in rats has been repeatedly demonstrated following intermittent-access (IntA) training, where the reinforcer is only available for brief periods during a session, compared to continuous-access (ContA) training where the reinforcer is available throughout the session. The present study investigated whether different associations learned during training on the two procedures contributes to the effect. Two experiments tested the importance of the stimulus-response (S-R) and stimulus-outcome (S-O) associations between the IntA availability cues and the training response and reinforcer, respectively.
View Article and Find Full Text PDFThe present study used a rat choice model to test how cocaine or heroin economically interacted with two different nondrug reinforcers along the substitute-to-complement continuum. In Experiment 1, the nondrug alternative was the negative reinforcer timeout-from-avoidance (TOA)-that is, rats could press a lever to obtain a period of safety from footshock. One group of rats chose between cocaine and TOA and another group chose between heroin and TOA.
View Article and Find Full Text PDFThe study of Alcohol Use Disorders (AUD) in preclinical models is hampered by difficulty in training rodents to voluntarily consume high levels of alcohol. The intermittency of alcohol access/exposure is well known to modulate alcohol consumption (e.g.
View Article and Find Full Text PDFThe intermittent-access (IntA) self-administration procedure has been reported to produce intensified addiction-like behavior compared to continuous-access (ContA) procedures. In a common variation of the IntA procedure, cocaine is available for 5 min at the beginning of each half hour of a 6-h session. In contrast, during ContA procedures, cocaine is available continuously throughout a session, typically lasting one or more hours.
View Article and Find Full Text PDFNeuropsychopharmacology
March 2023
It has recently been proposed that the intermittent access (IntA) drug self-administration procedure better produces behavioral changes relevant to addiction than the long access (LgA) procedure. In this version of the IntA procedure, the drug is made available for a 5-min period during each half hour of a 6-h session. In contrast, on the LgA procedure, the drug is available continuously for 6 h.
View Article and Find Full Text PDFOpioid use disorder imposes great societal harm in the United States and in countries worldwide. Animal models that accurately capture motivational changes that occur in opioid dependence are critical to studying this disorder. The present study used a model of opioid vapor self-administration combined with a behavioral economics approach to determine whether rats would be more motivated to "work" to defend their baseline intake of fentanyl (i.
View Article and Find Full Text PDFRationale: In a previous study, investigating choice between heroin and a non-drug alternative in animals and reductions in income (i.e., choices/day) caused the percentage of income spent on heroin to progressively decrease.
View Article and Find Full Text PDFPrevious studies found that opening the cocaine economy by providing postsession access to cocaine had no effect on animals' demand for cocaine, whereas postsession access to saccharin or food made demand for these nondrug reinforcers more elastic. It is possible that there was no effect of economy type on cocaine taking in these earlier studies because of the delay to the postsession cocaine in the open economy. The present experiment tested whether forming an open economy by providing additional within-session cocaine, rather than postsession cocaine, would make rats' demand for cocaine more elastic.
View Article and Find Full Text PDFRecent research from our laboratories has demonstrated that long-term and ad libitum high fat diet (HFD) consumption during adolescence and adulthood increases the intravenous self-administration (IVSA) of cocaine in adult male Sprague-Dawley rats. One possible interpretation of these findings is that this dietary history influences the affective properties of cocaine, that is, cocaine's rewarding and/or aversive effects. In this context, our research and others suggest that the overall affective response to a drug, and its potential for use and abuse, reflects a balance between these properties in which the rewarding effects of a drug maintain its use and the aversive effects limit it.
View Article and Find Full Text PDFPharmacol Biochem Behav
September 2019
Previous studies have shown that providing rats with a non-drug alternative in a choice situation can reduce ethanol taking in rats. There is also evidence that brief experience with non-drug reinforcers can reduce the reinforcing effects of drugs like cocaine, even when those non-drug alternatives are not pitted against the drug in a choice procedure. The goal of the present experiment was to determine whether experience with sucrose - a high value non-drug reinforcer in rats - in a non-choice situation would reduce ethanol's reinforcing effects, as measured within a behavioral economic framework.
View Article and Find Full Text PDFIn preclinical populations, binge consumption of a high-fat diet (HFD) initiated during either adolescence or adulthood increases the intravenous self-administration (IVSA) of cocaine, whereas ad lib HFD consumption initiated during adulthood reduces or fails to influence cocaine intake. From this, it appears that binge exposure is a sufficient condition to increase cocaine IVSA and that such effects occur independent of the exposure period. It is not clear, however, if ad lib exposure would be sufficient to affect the IVSA of cocaine if initiated during adolescence, a developmental period associated with high-risk behavior.
View Article and Find Full Text PDFExp Clin Psychopharmacol
December 2019
According to behavioral economics, reinforcer value should be lower in an open economy than in a closed economy. An animal model was used to determine how economy type affected the value of heroin and saccharin. In a first phase, separate groups of rats worked for heroin or saccharin.
View Article and Find Full Text PDFThis article reviews studies investigating the effect of economy type on reinforcer value. In a closed economy, consumption of the reinforcer depends entirely on the subject's behavior, whereas in an open economy it does not, due, for example, to the provision of free reinforcers after the session. In theory, reinforcers should have higher value in a closed economy than in an open economy.
View Article and Find Full Text PDFBackground: Economy type is an important determinant of reinforcer value. This study investigated the effect of open and closed economies on demand and preference for cocaine and saccharin in rats.
Methods: In the first phase, rats were trained to lever press for cocaine infusions or saccharin.
This report evaluates whether a rat releasing a trapped rat from a restraint tube is better explained as due to its empathic motivation or to the pursuit of social contact. In the first condition, each of six rats chose in an E maze between entering an empty goal box versus entering a goal box where its entrance caused a rat trapped in a restraint tube to be released. Rats preferred the goal box with the trapped rat over the empty goal box.
View Article and Find Full Text PDFPrevious research has shown that diets high in fat and sugar [a.k.a.
View Article and Find Full Text PDFPharmacol Biochem Behav
January 2018
This article serves to summarize this special issue on "Decision-making in Addiction." The manuscripts included in this issue cover topics as diverse as theory, types of models used to study decision-making, underlying pharmacological, behavioral and brain mechanisms, and individual differences. Together, these papers can serve as a comprehensive resource outlining our contemporary understanding of how decision-making processes contribute to addictive behavior.
View Article and Find Full Text PDFThe aim of the present study was to determine how nicotine pre-exposure affects the elasticity of demand for intravenous cocaine and for sucrose pellets in adult male rats. In Experiment 1, demand for cocaine was assessed in rats that had nicotine in their drinking water. Nicotine pre-exposure significantly decreased rats' willingness to defend cocaine consumption as the price (measured as the number of responses per cocaine infusion) increased compared with a control group with no nicotine pre-exposure.
View Article and Find Full Text PDFAlcohol exposure in adolescence is a contributing factor toward reward-seeking behavior in adulthood. This reward-seeking behavior is assessed in animal models using the conditioned place preference (CPP) paradigm. In this study, ethanol-induced change in time spent by zebrafish on the initially non-preferred tank side was studied by conditioning adult zebrafish to ethanol dissolved in water (0.
View Article and Find Full Text PDFBackground: Several recent studies have investigated the choice between heroin and a non-drug alternative reinforcer in rats. A common finding in these studies is that there are large individual differences in preference, with some rats preferring heroin and some preferring the non-drug alternative. The primary goal of the present study was to determine whether individual differences in how heroin or saccharin is valued, based on demand analysis, predicts choice.
View Article and Find Full Text PDFIn Experiment 1, rats choosing in an E maze preferred to release a rat standing in a pool of water to dry ground over a rat already standing on dry ground. Five additional experiments showed that the choosing rat's preference for releasing the wet rat was maintained by two separable outcomes: (1) the social contact offered by the released rat and (2) the reinforcing value of proximity to a pool of water. These results call into question Sato et al.
View Article and Find Full Text PDFThis study investigated the relationship between reinforcer value and choice between cocaine and two non-drug alternative reinforcers in rats. The essential value (EV, a behavioral economic measure based on elasticity of demand) of intravenous cocaine and food (Experiment 1) or saccharin (Experiment 2) was determined in the first phase of each experiment. Food had higher EV than cocaine, whereas the EVs of cocaine and saccharin did not differ.
View Article and Find Full Text PDFThe present experiment tested whether the elasticity of demand for self-administered cocaine in rats is dose-dependent. Subjects lever pressed for three different doses of intravenous cocaine - 0.11, 0.
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