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Smith TR, Southern R, Kirkpatrick K. Mechanisms of impulsive choice: Experiments to explore and models to map the empirical terrain. Learn Behav 2023; 51:355-391. [PMID: 36913144 PMCID: PMC10497727 DOI: 10.3758/s13420-023-00577-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 03/14/2023]
Abstract
Impulsive choice is preference for a smaller-sooner (SS) outcome over a larger-later (LL) outcome when LL choices result in greater reinforcement maximization. Delay discounting is a model of impulsive choice that describes the decaying value of a reinforcer over time, with impulsive choice evident when the empirical choice-delay function is steep. Steep discounting is correlated with multiple diseases and disorders. Thus, understanding the processes underlying impulsive choice is a popular topic for investigation. Experimental research has explored the conditions that moderate impulsive choice, and quantitative models of impulsive choice have been developed that elegantly represent the underlying processes. This review spotlights experimental research in impulsive choice covering human and nonhuman animals across the domains of learning, motivation, and cognition. Contemporary models of delay discounting designed to explain the underlying mechanisms of impulsive choice are discussed. These models focus on potential candidate mechanisms, which include perception, delay and/or reinforcer sensitivity, reinforcement maximization, motivation, and cognitive systems. Although the models collectively explain multiple mechanistic phenomena, there are several cognitive processes, such as attention and working memory, that are overlooked. Future research and model development should focus on bridging the gap between quantitative models and empirical phenomena.
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2
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Johnson BN, Allen MI, Reboussin BA, LaValley C, Nader MA. Delay discounting as a behavioral phenotype associated with social rank in female and male cynomolgus monkeys: Correlation with kappa opioid receptor availability. Pharmacol Biochem Behav 2023; 225:173545. [PMID: 37004977 PMCID: PMC10732250 DOI: 10.1016/j.pbb.2023.173545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Cocaine use disorder (CUD) is a significant problem worldwide, with no FDA-approved treatments. Epidemiological data indicate that only about 17 % of people that use cocaine will meet DSM criteria for CUD. Thus, the identification of biomarkers predictive of eventual cocaine use may be of great value. Two potentially useful predictors of CUD are social hierarchies in nonhuman primates and delay discounting. Both social rank and preference for a smaller, immediate reinforcer relative to a larger, delayed reinforcer have been predictive of CUD. Therefore, we wanted to determine if there was also a relationship between these two predictors of CUD. In the present study, monkeys cocaine-naive responded under a concurrent schedule of 1- vs. 3-food pellets and delivery of the 3-pellet option was delayed. The primary dependent variable was the indifference point (IP), which is the delay that results in 50 % choice for both options. In the initial determination of IP, there were no differences based on sex or social rank of the monkeys. When the delays were redetermined after ~25 baseline sessions (range 5-128 sessions), dominant females and subordinate males showed the largest increases in IP scores from the first determination to the second. Because 13 of these monkeys had prior PET scans of the kappa opioid receptor (KOR), we examined the relationship between KOR availability and IP values and found that the change in IP scores from the first to the second determination significantly negatively predicted average KOR availability in most brain regions. Future studies will examine acquisition to cocaine self-administration in these same monkeys, to determine if IP values are predictive of vulnerability to cocaine reinforcement.
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Affiliation(s)
- Bernard N Johnson
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, United States of America
| | - Mia I Allen
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, United States of America
| | - Beth A Reboussin
- Department of Biostatistics, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, United States of America
| | - Christina LaValley
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, United States of America
| | - Michael A Nader
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, United States of America.
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3
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Zamarripa CA, Doyle WS, Freeman KB, Rowlett JK, Huskinson SL. Choice between food and cocaine reinforcers under fixed and variable schedules in female and male rhesus monkeys. Exp Clin Psychopharmacol 2023; 31:204-218. [PMID: 35099243 PMCID: PMC9339013 DOI: 10.1037/pha0000547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Illicit drugs like cocaine may be uncertain in terms of the time and effort required to obtain them. Behavior maintained by variable schedules resembles excessive drug-taking compared with fixed schedules. However, no prior research has examined fixed versus variable schedules in drug versus nondrug choice. The present study evaluated cocaine versus food choice under fixed- (FR) and variable-ratio (VR) schedules. The simpler food versus food and cocaine versus cocaine arrangements also were included. Adult female (n = 6) and male (n = 7) rhesus monkeys chose between cocaine (0.01-0.18 mg/kg/injection) and food (4 pellets/delivery), food and food (4 pellets/delivery), or cocaine and cocaine (0.018-0.03 mg/kg/injection) under FR and VR 100 and 200 schedules. In cocaine versus food choice, cocaine's potency to maintain choice was greatest when available under a VR 100 or 200 schedule and food under an FR schedule and was lowest when cocaine was available under an FR 200 schedule and food was available under a VR 200 schedule. In food versus food choice, males chose food associated with a VR schedule more than food associated with an FR schedule. In cocaine versus cocaine choice, females and males chose cocaine associated with a VR schedule more than cocaine associated with an FR schedule, particularly under VR 200. These findings suggest that uncertainty in terms of time and effort required to obtain cocaine, or perhaps the occasional low-cost access that results from VR schedules, results in greater allocation of behavior toward drug reinforcers at the expense of more certain, nondrug alternatives. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Affiliation(s)
- C. Austin Zamarripa
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
| | - William S. Doyle
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
| | - Kevin B. Freeman
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
| | - James K. Rowlett
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
| | - Sally L. Huskinson
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
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Estle SJ, Green L, Myerson J, Yeh YH. Discounting of outcomes in which immediate gains are followed by delayed losses. J Exp Anal Behav 2023; 119:36-48. [PMID: 36511664 PMCID: PMC9868072 DOI: 10.1002/jeab.813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/17/2022] [Accepted: 11/24/2022] [Indexed: 12/15/2022]
Abstract
Previous discounting research has focused on relatively simple situations (e.g., choosing between immediate and delayed gains, or between immediate and delayed losses) and the relations among amount, delay, and subjective value in such situations are now well established. Many everyday choice situations, however, are more complex, involving alternatives that combine gains and losses. In two experiments, participants discounted a monetary outcome that combined an immediate gain with a delayed loss. Consistent with the discounting framework, the value of the combination was approximately equal to the difference between the (undiscounted) value of the immediate gain and the (discounted) value of the delayed loss. More precise predictions of the relative subjective value of the delayed loss component of a combination were given by the same hyperboloid function that describes discounting in simple choice situations where outcomes only involve gains or losses, not both. As in previous studies, when the outcome was a simple one consisting of only a delayed loss, discounting was not affected by the amount of that loss. Surprisingly, however, when the loss was preceded by a gain, the degree to which the combination was discounted was affected by the amount of the loss. Notably, discounting of the delayed loss component of the combination decreased with the amount of the loss in a fashion similar to that observed with simple delayed gains, where smaller amounts are discounted more steeply than larger amounts. Choice situations involving immediate gains followed by delayed losses pose iconic self-control problems, and the present findings support the application of the discounting framework to these important everyday problems.
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Affiliation(s)
- Sara J. Estle
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill
| | - Leonard Green
- Department of Psychological & Brain Sciences, Washington University in St. Louis
| | - Joel Myerson
- Department of Psychological & Brain Sciences, Washington University in St. Louis
| | - Yu-Hua Yeh
- Fralin Biomedical Research Institute at VTC
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Parikh A, Moeller SJ, Garland EL. Simulated opioid choice linked to opioid use disorder severity among veterans with chronic pain: initial validation of a novel paradigm. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2022; 48:403-412. [PMID: 35100056 PMCID: PMC9339010 DOI: 10.1080/00952990.2021.2007258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 06/14/2023]
Abstract
Background: Modeling addictive behavior among individuals with, or at risk for, opioid use disorder (OUD) in a way that is accurate, ethical, and reproducible presents a pressing concern. OUD risk is elevated among people with chronic pain on long-term opioid therapy (LTOT).Objectives: To provide initial validation of a novel opioid preference task as an index of OUD and its symptomatology among veterans prescribed opioids for chronic pain, a population at high risk for poor opioid-related outcomes. The relative ease by which such a paradigm can be implemented and performed in clinical contexts, including enabling investigation of opioid reinforcement and drug-seeking behavior while avoiding ethical pitfalls associated with direct drug administration, could make this task an attractive approach for potentially tracking OUD symptoms.Methods: We studied 87 veterans (74 males, 13 females) on LTOT for chronic pain - 33 of whom had OUD diagnoses. Participants completed a picture-viewing choice task to assess preference for viewing opioid-related images in comparison with standardized pleasant, unpleasant, neutral, and blank images. Opioid-related choice, measured by vigor of button pressing, was tested for association with OUD severity (measured by symptom counts), as well as craving and anhedonia.Results: Choice for opioid-related images was positively correlated with OUD severity (i.e., number of DSM-5 measured OUD symptoms) (r = 0.38, p < .001), particularly among those meeting diagnostic criteria for OUD (r = 0.47, p = .006). Neither craving nor anhedonia correlated with opioid-related choice.Conclusions: Our results provide initial validation for a new opioid picture-choice paradigm in patients with chronic pain.
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Affiliation(s)
- Apurva Parikh
- Department of Psychiatry, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY
| | - Scott J. Moeller
- Department of Psychiatry, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY
| | - Eric L. Garland
- University of Utah Center on Mindfulness and Integrative Health Intervention Development, Salt Lake City, UT
- College of Social Work, University of Utah, Salt Lake City, UT
- Veterans Health Care Administration VISN 19 Whole Health Flagship site located at the VA Salt Lake City Health Care System, Salt Lake City, UT
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Chow JJ, Beacher NJ, Chabot JM, Oke M, Venniro M, Lin DT, Shaham Y. Characterization of operant social interaction in rats: effects of access duration, effort, peer familiarity, housing conditions, and choice between social interaction vs. food or remifentanil. Psychopharmacology (Berl) 2022; 239:2093-2108. [PMID: 35230469 PMCID: PMC10724845 DOI: 10.1007/s00213-022-06064-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/06/2022] [Indexed: 01/02/2023]
Abstract
RATIONALE AND OBJECTIVE Social factors play a critical role in drug addiction. We recently showed that rats will abstain from methamphetamine, cocaine, heroin, and remifentanil self-administration when given a choice between the addictive drug and operant social interaction. Here, we further characterized operant social interaction by determining the effects of access duration, effort, peer familiarity, and housing conditions. We also determined choice between social interaction vs. palatable food or remifentanil. METHODS We first trained single-housed male and female rats to lever-press for social interaction with a sex- and age-matched peer. Next, we determined effects of access duration (3.75 to 240 s), effort (increasing fixed-ratio schedule requirements or progressive ratio schedule), peer familiarity (familiar vs. unfamiliar), and housing conditions (single vs. paired housing) on social self-administration. We also determined choice between social interaction vs. palatable food pellets or intravenous remifentanil (0, 1, 10 µg/kg/infusion). RESULTS Increasing access duration to a peer decreased social self-administration under fixed ratio but not progressive ratio schedule; the rats showed similar preference for short vs. long access duration. Social self-administration under different fixed ratio requirements was higher in single-housed than in paired-housed rats and higher for a familiar vs. unfamiliar partner in single-housed but not paired-housed rats. Response rates of food-sated rats under increasing fixed-ratio requirements were higher for palatable food than for social interaction. The rats strongly preferred palatable food over social interaction and showed dose-dependent preference for social interaction vs. remifentanil. CONCLUSIONS We identified parameters influencing the reinforcing effects of operant social interaction and introduce a choice procedure sensitive to remifentanil self-administration dose.
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Affiliation(s)
| | | | - Jules M Chabot
- Intramural Research Program, NIDA, NIH, Baltimore, MD, USA
| | - Marvellous Oke
- Intramural Research Program, NIDA, NIH, Baltimore, MD, USA
| | - Marco Venniro
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Da-Ting Lin
- Intramural Research Program, NIDA, NIH, Baltimore, MD, USA
| | - Yavin Shaham
- Intramural Research Program, NIDA, NIH, Baltimore, MD, USA.
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7
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Haynes JM, Odum AL. Testing delay of gratification in rats using a within-session increasing-delay task. J Exp Anal Behav 2022; 118:3-23. [PMID: 35485644 DOI: 10.1002/jeab.767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/22/2022] [Accepted: 04/13/2022] [Indexed: 11/07/2022]
Abstract
In delay discounting, preference reversals refer to shifts in preference from a larger-later reward to a smaller-sooner reward. Steep hyperbolic discounting predicts a preference reversal when a smaller-sooner and larger-later reward both become temporally proximal; prior research is consistent with this prediction. Hyperbolic discounting does not predict a preference reversal, however, after an individual chooses a larger-later reward over a smaller-immediate reward; prior research is inconsistent with this prediction. We sought to replicate and extend these findings using a delay of gratification task in rats. The task included a defection response which allowed rats to reverse their preference after choosing a larger-later sucrose reinforcer to instead obtain a smaller-immediate sucrose reinforcer. In Experiment 1, we found that rats would defect on their choice of the larger-later reinforcer, systematically replicating prior research. We also found that experience on the delay of gratification task led to decreases in defection responses. In Experiment 2, we found that prior experience on an intertemporal choice task, with no opportunity to defect, also led to few defection responses on the delay of gratification task. We discuss our findings in the context of whether inhibitory control or temporal learning could be involved in delay of gratification.
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8
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Pfund RA, Cook JE, McAfee NW, Huskinson SL, Parker JD. Challenges to Conducting Contingency Management Treatment for Substance Use Disorders: Practice Recommendations for Clinicians. ACTA ACUST UNITED AC 2021; 52:137-145. [PMID: 34421192 DOI: 10.1037/pro0000356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A growing empirical literature supports contingency management (CM) as an efficacious treatment for substance use disorders, especially when reinforcers are immediate, frequent, and of sufficient magnitude on escalating schedules. However, in real world-practice, CM is often conducted in ways that are inconsistent with research protocols. One reason for these inconsistencies may be due to pragmatic challenges inherent in conducting CM. In this article, we described an outpatient CM treatment program for drug use disorders and several specific challenges associated with adherence to CM parameters from research protocols. Finally, we propose possible solutions for these challenges and discuss implications for practice.
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9
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A review of cross-commodity delay discounting research with relevance to addiction. Behav Processes 2021; 186:104339. [PMID: 33545318 DOI: 10.1016/j.beproc.2021.104339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/01/2020] [Accepted: 01/26/2021] [Indexed: 12/22/2022]
Abstract
Delay discounting (DD) refers to the decrease in the subjective value of a reward as the delay to its receipt increases. As high rates of DD are consistently associated with measures of substance misuse, DD is an important construct in current conceptualizations of addiction. High rates of DD appear to model preference for the immediate rewards provided by substance use, resulting in the interpretation that individuals with substance use disorder are generally unable or unwilling to delay gratification to obtain larger but delayed rewards. This interpretation is largely based on literature implementing binary choice tasks using differing amounts of the same commodity (i.e., single-commodity), in which high rates of DD can result from relative preference for the immediate outcome or relative dispreference for the delayed outcome. We propose that tasks using different commodities (i.e., cross-commodity) for the immediate and delayed outcomes offer potential in disentangling these dissociable and consequentially distinct interpretations. Our review suggests that cross-commodity DD tasks provide unique insights into understanding addiction not captured by single-commodity designs. We conclude that more research implementing cross-commodity DD tasks is needed to better understand the role of intertemporal choice in addiction and recovery.
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10
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Huskinson SL. Unpredictability as a modulator of drug self-administration: Relevance for substance-use disorders. Behav Processes 2020; 178:104156. [PMID: 32526314 DOI: 10.1016/j.beproc.2020.104156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/14/2020] [Accepted: 05/29/2020] [Indexed: 01/05/2023]
Abstract
Drug self-administration has been regarded as a gold-standard preclinical model of addiction and substance-use disorder (SUD). However, investigators are becoming increasingly aware, that certain aspects of addiction or SUDs experienced by humans are not accurately captured in our preclinical self-administration models. The current review will focus on two such aspects of current preclinical drug self-administration models: 1) Predictable vs. unpredictable drug access in terms of the time and effort put into obtaining drugs (i.e., response requirement) and drug quality (i.e., amount) and 2) rich vs. lean access to drugs. Some behavioral and neurobiological mechanisms that could contribute to excessive allocation of behavior toward drug-seeking and drug-taking at the expense of engaging in nondrug-related activities are discussed, and some directions for future research are identified. Based on the experiments reviewed, lean and unpredictable drug access could worsen drug-seeking and drug-taking behavior in individuals with SUDs. Once more fully explored, this area of research will help determine whether and how unpredictable and lean cost requirements affect drug self-administration in preclinical laboratory studies with nonhuman subjects and will help determine whether incorporating these conditions in current self-administration models will increase their predictive validity.
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Affiliation(s)
- Sally L Huskinson
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500N. State Street, Jackson, MS, 39216, United States.
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11
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Sampedro-Piquero P, Ávila-Gámiz F, Moreno Fernández RD, Castilla-Ortega E, Santín LJ. The presence of a social stimulus reduces cocaine-seeking in a place preference conditioning paradigm. J Psychopharmacol 2019; 33:1501-1511. [PMID: 31542987 DOI: 10.1177/0269881119874414] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND One challenge in the treatment of substance use disorders is to re-engage the interest toward non-drug-related activities. Among these activities, social interaction has had a prominent role due to its positive influence on treatment outcome. AIMS AND METHODS Our aim was to study whether the presence of a social stimulus during the cocaine-induced conditioned place preference test was able to reduce the time spent in the drug-paired compartment. For that purpose, mice were trained for four days on a conditioned place preference task with one compartment paired with cocaine and the opposite with saline. On the test day, we introduced an unfamiliar juvenile male mouse into the saline-conditioned compartment (inside a pencil cup) to analyse the animal preference towards the two rewarding stimuli (cocaine vs mouse). Additionally, to discard the possible effect of novelty, as well as the housing condition (social isolation) on social preference, we decided to include a novel object during the test session, as well as perform the same conditioned place preference protocol with a group of animals in social housing conditions. RESULTS The social stimulus was able to reduce the preference for cocaine and enhance the active interaction with the juvenile mouse (sniffing) compared to the empty pencil cup paired with the drug. The introduction of a novel object during the test session did not reduce the preference for the cocaine-paired compartment, and interestingly, the preference for the social stimulus was independent of the housing condition. c-Fos immunohistochemistry revealed a different pattern of activation based on cocaine-paired conditioning or the presence of social stimulus. CONCLUSIONS These results suggest that social interaction could constitute a valuable component in the treatment of substance use disorders by reducing the salience of the drug.
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Affiliation(s)
- Patricia Sampedro-Piquero
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Malaga, Spain
| | - Fabiola Ávila-Gámiz
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Malaga, Spain
| | - Román D Moreno Fernández
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Malaga, Spain
| | - Estela Castilla-Ortega
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.,Unidad de Gestión Clínica de Salud Mental, Hospital Regional Universitario de Málaga, Malaga, Spain
| | - Luis J Santín
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Malaga, Spain
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Abstract
Although steep delay discounting is associated with various behavioral problems, perhaps most prominently substance abuse, we argue that it is best not conceived of as a character flaw such as impulsivity. Such a view, although part of a centuries-old tradition, does not distinguish between actions whose outcomes involve gains and losses, or between delayed outcomes and probabilistic outcomes, nor does it acknowledge that how steeply an individual discounts one of these kinds of outcome appears to be independent of how steeply they discount other kinds. Therefore, we advocate an approach that does not require making judgments about the character of the individuals involved. We show that when drug-dependent individuals are compared with controls, a substantial number of the drug-dependent individuals discount delayed monetary rewards less steeply than the average (median) member of the control group. Moreover, a substantial number of the controls discount more steeply than the average drug-dependent individual. Finally, we point out that many everyday choice situations differ from those studied in most discounting experiments in that they involve both gains and losses as well as qualitatively different outcomes that may be both delayed and probabilistic. Past research on discounting that focused on simple choice situations has provided a solid foundation, but research on more complicated situations is now needed. We believe that the principles revealed by such research will both inform the choices of treatment providers and improve our understanding of the complicated decisions that people face every day.
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Affiliation(s)
- Leonard Green
- Department of Psychological & Brain Sciences, Washington University in St. Louis, Campus Box 1125, St. Louis, MO 63130 USA
| | - Joel Myerson
- Department of Psychological & Brain Sciences, Washington University in St. Louis, Campus Box 1125, St. Louis, MO 63130 USA
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13
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Ahmed SH. Trying to make sense of rodents' drug choice behavior. Prog Neuropsychopharmacol Biol Psychiatry 2018; 87:3-10. [PMID: 28965843 DOI: 10.1016/j.pnpbp.2017.09.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 12/14/2022]
Abstract
Since the first experimental hint for the existence of "an actual desire or striving for the drug" in nonhuman animals by Sidney Spragg in the late 1930s, much effort has been expended by lab researchers to try to model in a valid manner the key behavioral aspects and signs of addiction in animals, typically in rodents (i.e., mainly rats and, to a lesser extent, mice). Despite much advances, there still remains a lingering doubt about the disordered status of drug use in rodents. This is mainly because drug use occurs in a particular setting where animals have access to a drug for self-administration but without access to other valuable behavioral options that could compete with and divert from drug use. Here I review evidence showing that enriching the drug setting with other behavioral options can dramatically influence the pattern of drug choices in rodents. Overall, access to other options during drug access can divert the vast majority of rats from continued drug use. Only few individuals continue to engage in drug use despite access to and at the expense of other options. However, there exist certain high-risk settings in which virtually all animals are vulnerable to develop a harmful pattern of exclusive drug use that can even become fatal in the long run if not discontinued by an outside intervention. Paradoxically, it appears that the behavioral trait that is hypothesized to uniquely render rodents vulnerable to the latter settings (i.e., a narrow focus on the local, current choice, with no consideration of the global pattern of choice) would also protect most of them from using drugs in other choice settings. I conclude with an attempt to make sense of this peculiar setting-specific behavior and with some general propositions for future research.
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Affiliation(s)
- Serge H Ahmed
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 146 rue Léo-Saignat, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 146 rue Léo-Saignat, F-33000 Bordeaux, France.
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14
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Renee Renda C, Rung JM, Hinnenkamp JE, Lenzini SN, Madden GJ. Impulsive choice and pre-exposure to delays: iv. effects of delay- and immediacy-exposure training relative to maturational changes in impulsivity. J Exp Anal Behav 2018; 109:587-599. [PMID: 29683190 DOI: 10.1002/jeab.432] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 04/02/2018] [Indexed: 12/31/2022]
Abstract
Impulsive choice describes preference for smaller, sooner rewards over larger, later rewards. Excessive delay discounting (i.e., rapid devaluation of delayed rewards) underlies some impulsive choices, and is observed in many maladaptive behaviors (e.g., substance abuse, gambling). Interventions designed to reduce delay discounting may provide therapeutic gains. One such intervention provides rats with extended training with delayed reinforcers. When compared to a group given extended training with immediate reinforcers, delay-exposed rats make significantly fewer impulsive choices. To what extent is this difference due to delay-exposure training shifting preference toward self-control or immediacy-exposure training (the putative control group) shifting preference toward impulsivity? The current study compared the effects of delay- and immediacy-exposure training to a no-training control group and evaluated within-subject changes in impulsive choice across 51 male Wistar rats. Delay-exposed rats made significantly fewer impulsive choices than immediacy-exposed and control rats. Between-group differences in impulsive choice were not observed in the latter two groups. While delay-exposed rats showed large, significant pre- to posttraining reductions in impulsive choice, immediacy-exposed and control rats showed small reductions in impulsive choice. These results suggest that extended training with delayed reinforcers reduces impulsive choice, and that extended training with immediate reinforcers does not increase impulsive choice.
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Choosing the right delay-discounting task: Completion times and rates of nonsystematic data. Behav Processes 2018; 151:119-125. [PMID: 29604331 DOI: 10.1016/j.beproc.2018.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 03/13/2018] [Accepted: 03/27/2018] [Indexed: 11/21/2022]
Abstract
A variety of delay discounting tasks are widely used in human studies designed to quantify the degree to which individuals discount the value of delayed rewards. It is currently unknown which task(s) yields the largest proportion of valid and systematic data using standard criteria (Johnson & Bickel, 2008). The goal of this study was to compare three delay-discounting tasks on task duration and amount of valid and systematic data produced. In Experiment 1, 180 college students completed one of three tasks online (fixed alternatives, titrating, or visual analogue scale [VAS]). Invalid and nonsystematic data, identified using standard criteria, were most prevalent with the VAS (47.3% of participants). The other tasks produced more (and similar amounts of) valid and systematic data, but required more time to complete than the VAS. Viewing systematic data as more important than completion times, Experiment 2 (n = 153 college students) sought to reduce the amount of invalid datasets in the fixed-alternatives task, and compare amounts of nonsystematic data with the titrating task. Completion times were superior in the titrating task, which produced modestly more systematic data than the fixed-alternatives task. Causes of invalid and nonsystematic data are discussed, as are methods for reducing data exclusion.
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16
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Ahmed SH. Individual decision-making in the causal pathway to addiction: contributions and limitations of rodent models. Pharmacol Biochem Behav 2018; 164:22-31. [DOI: 10.1016/j.pbb.2017.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/16/2017] [Accepted: 07/10/2017] [Indexed: 12/23/2022]
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Perkins FN, Freeman KB. Pharmacotherapies for decreasing maladaptive choice in drug addiction: Targeting the behavior and the drug. Pharmacol Biochem Behav 2018; 164:40-49. [PMID: 28666892 PMCID: PMC5745300 DOI: 10.1016/j.pbb.2017.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/06/2017] [Accepted: 06/26/2017] [Indexed: 12/23/2022]
Abstract
Drug addiction can be conceptualized as a disorder of maladaptive decision making in which drugs are chosen at the expense of pro-social, nondrug alternatives. The study of decision making in drug addiction has focused largely on the role of impulsivity as a facilitator of addiction, in particular the tendency for drug abusers to choose small, immediate gains over larger but delayed outcomes (i.e., delay discounting). A parallel line of work, also focused on decision making in drug addiction, has focused on identifying the determinants underlying the choice to take drugs over nondrug alternatives (i.e., drug vs. nondrug choice). Both tracks of research have been valuable tools in the development of pharmacotherapies for treating maladaptive decision making in drug addiction, and a number of common drugs have been studied in both designs. However, we have observed that there is little uniformity in the administration regimens of potential treatments between the designs, which hinders congruence in the development of single treatment strategies to reduce both impulsive behavior and drug choice. The current review provides an overview of the drugs that have been tested in both delay-discounting and drug-choice designs, and focuses on drugs that reduced the maladaptive choice in both designs. Suggestions to enhance congruence between the findings in future studies are provided. Finally, we propose the use of a hybridized, experimental approach that may enable researchers to test the effectiveness of therapeutics at decreasing impulsive and drug choice in a single design.
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Affiliation(s)
- Frank N Perkins
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, United States
| | - Kevin B Freeman
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, United States.
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Choice between delayed food and immediate opioids in rats: treatment effects and individual differences. Psychopharmacology (Berl) 2017; 234:3361-3373. [PMID: 28868576 PMCID: PMC5664176 DOI: 10.1007/s00213-017-4726-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/20/2017] [Indexed: 02/03/2023]
Abstract
RATIONALE Addiction involves maladaptive choice behavior in which immediate drug effects are valued more than delayed nondrug rewards. OBJECTIVES AND METHODS To model this behavior and extend our earlier work with the prescription opioid oxycodone, we allowed rats to choose between immediate intravenous delivery of the short-acting opioid remifentanil and delayed delivery of highly palatable food pellets. Treatment drugs were tested on a baseline where remifentanil was preferred over food. RESULTS Treatment with a high dose of the opioid antagonist naltrexone decreased but did not reverse the preference for remifentanil. Treatment with the serotonin 5-HT2C agonist lorcaserin decreased remifentanil and food self-administration nonselectively. Across conditions in which the alternative to delayed food was either a moderate dose of oxycodone, a moderate or high dose of remifentanil, a smaller more immediate delivery of food, or timeout with no primary reinforcement, choice was determined by both the length of the delay and the nature of the alternative option. Delayed food was discounted most steeply when the alternative was a high dose of remifentanil, which was preferred over food when food was delayed by 30 s or more. Within-subject comparisons showed no evidence for trait-like impulsivity or sensitivity to delay across these conditions. CONCLUSIONS Choice was determined more by the current contingencies of reinforcement than by innate individual differences. This finding suggests that people might develop steep delay-discounting functions because of the contingencies in their environment, and it supports the use of contingency management to enhance the relative value of delayed nondrug reinforcers.
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Huskinson S, Freeman K, Petry N, Rowlett J. Choice between variable and fixed cocaine injections in male rhesus monkeys. Psychopharmacology (Berl) 2017; 234:2353-2364. [PMID: 28601964 PMCID: PMC5695214 DOI: 10.1007/s00213-017-4659-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/22/2017] [Indexed: 11/29/2022]
Abstract
RATIONALE The schedule of drug availability may enhance choice of a drug. In non-human subjects, reinforcers are chosen more often when available under variable schedules of reinforcement relative to fixed schedules. OBJECTIVE To determine whether variable-drug access is an important determinant of cocaine choice by manipulating the schedule, drug dose, and combination of schedule + dose. METHOD Four male rhesus monkeys chose between cocaine doses (0.025-0.4 mg/kg/injection). In control conditions, the schedule and dose of each drug delivery were fixed. In other conditions, the reinforcement schedule (i.e., variable-ratio schedule), dose of each cocaine delivery, or both were variable on one lever while all aspects on the other lever remained fixed. RESULTS When cocaine dose was equal on average (0.1 mg/kg/injection), 2 of 4 subjects chose cocaine associated with the variable schedule more than the fixed schedule. All subjects chose the variable dose that was equal on average to the fixed dose, and this difference was statistically significant. Three of 4 subjects chose cocaine associated with the variable combination over the fixed option (when the dose was equal on average). During dose-response determinations (when dose on the variable and fixed options were not equal), making the schedule, dose, or both variable generally did not alter cocaine's potency as a reinforcer. CONCLUSION While many factors contribute to drug choice, unpredictable drug access is a feature that may be common in the natural environment and could play a key role in the allocation of behavior to drug alternatives by patients with substance-use disorders.
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Affiliation(s)
- S.L. Huskinson
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
| | - K.B. Freeman
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216,Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216
| | - N.M. Petry
- University of Connecticut School of Medicine, Farmington, CT 06030
| | - J.K. Rowlett
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216,Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216,Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA 70433
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20
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Negus SS, Banks ML. Modulation of drug choice by extended drug access and withdrawal in rhesus monkeys: Implications for negative reinforcement as a driver of addiction and target for medications development. Pharmacol Biochem Behav 2017; 164:32-39. [PMID: 28442370 DOI: 10.1016/j.pbb.2017.04.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/20/2017] [Accepted: 04/18/2017] [Indexed: 11/24/2022]
Abstract
Chronic drug exposure is hypothesized to recruit negative reinforcement processes that increase the magnitude and alter the mechanisms of drug reinforcement. Candidate substrates of negative reinforcement include increased signaling via stress-related neurotransmitters such as corticotropin releasing factor (CRF, acting at CRF receptors) or dynorphin (acting at kappa opioid receptors) and/or decreased signaling via reward-related neurotransmitters such as dopamine. Determinants of drug reinforcement can be examined with choice procedures, in which subjects choose between a drug of interest (e.g. heroin or cocaine) and a non-drug alternative reinforcer (e.g. food). This review summarizes evidence collected from studies of drug choice in rhesus monkeys to address the negative reinforcement hypothesis. In monkeys choosing between heroin and food, chronic heroin exposure and subsequent withdrawal produces a robust increase in heroin choice. This withdrawal-associated increase in heroin choice is blocked by morphine and by other mu opioid agonists used to treat opioid use disorder (methadone, buprenorphine); however, withdrawal-associated increases in heroin choice are not reliably blocked by antagonists of CRF or kappa opioid receptors or by an indirect dopamine agonist. In monkeys choosing between cocaine and food, chronic cocaine exposure and withdrawal fail to increase cocaine choice or alter sensitivity of cocaine choice to treatment with candidate therapeutics including an indirect dopamine agonist and a kappa opioid receptor antagonist. These results support a role for negative reinforcement in self-administration of heroin but not cocaine. The constellation of neurobiological changes that constitutes the negative reinforcing stimulus in opioid-dependent rhesus monkeys remains to be determined.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
| | - Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
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21
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Banks ML, Negus SS. Insights from Preclinical Choice Models on Treating Drug Addiction. Trends Pharmacol Sci 2017; 38:181-194. [PMID: 27916279 PMCID: PMC5258826 DOI: 10.1016/j.tips.2016.11.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/02/2016] [Accepted: 11/07/2016] [Indexed: 02/07/2023]
Abstract
Substance-use disorders are a global public health problem that arises from behavioral misallocation between drug use and more adaptive behaviors maintained by nondrug alternatives (e.g., food or money). Preclinical drug self-administration procedures that incorporate a concurrently available nondrug reinforcer (e.g., food) provide translationally relevant and distinct dependent measures of behavioral allocation (i.e., to assess the relative reinforcing efficacy of the drug) and behavioral rate (i.e., to assess motor competence). In particular, preclinical drug versus food 'choice' procedures have produced increasingly concordant results with both human laboratory drug self-administration studies and double-blind placebo-controlled clinical trials. Accordingly, here we provide a heuristic framework of substance-use disorders based on a behavioral-centric perspective and recent insights from these preclinical choice procedures.
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Affiliation(s)
- Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
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22
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Abstract
Although increased impulsivity (delay discounting) is an important risk factor for drug abuse, the impact of delay on drug taking has received relatively little attention. This study examined delay discounting of the μ-opioid receptor agonist remifentanil in rhesus monkeys (n=4) responding for intravenous infusions under a concurrent choice procedure. Dose-effect curves for remifentanil were determined by varying the dose available on one lever (0.001-0.32 μg/kg/infusion) while keeping the dose available on the other lever (0.1 μg/kg/infusion) the same. Dose-effect curves were determined when both infusions were delivered immediately and when delivery of the fixed dose was delayed (15-180 s). When both doses of remifentanil were delivered immediately, monkeys chose the large dose. Delaying delivery of the fixed dose reduced choice of that dose and increased choice of small immediately available doses. Extending previous studies, these results show that the effects of delay on choice between two doses of a μ-opioid receptor agonist are consistent with hyperbolic discounting. Delaying delivery of a preferred reinforcer (e.g. large dose of drug) reduces its effectiveness and increases the effectiveness of small immediately available doses. This effect of delay, particularly on drug self-administration, might contribute to drug abuse.
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23
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Huskinson SL, Myerson J, Green L, Rowlett JK, Woolverton WL, Freeman KB. Shallow discounting of delayed cocaine by male rhesus monkeys when immediate food is the choice alternative. Exp Clin Psychopharmacol 2016; 24:456-463. [PMID: 27929348 PMCID: PMC5152690 DOI: 10.1037/pha0000098] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Huskinson et al. (2015) recently examined delay discounting in monkeys choosing between an immediate drug (cocaine) reinforcer and a delayed nondrug (food) reinforcer. The present experiment examined the reverse situation: choice between immediate nondrug (food) and delayed drug (cocaine) reinforcers. Whereas the former choice situation exemplifies drug abuse from a delay-discounting perspective, our interest in the latter choice situation is derived from the observation that drug abusers, who characteristically are associated with impulsive choice, typically must devote considerable time to procuring drugs, often at the expense of immediate nondrug alternatives. Accordingly, we analyzed 3 male rhesus monkeys' choices between immediate food and delayed cocaine (0.1 and 0.2 mg/kg/injection) using a hyperbolic model that allowed us to compare discounting rates between qualitatively different reinforcers. Choice of immediate food increased with food amount, and choice functions generally shifted leftward as delay to cocaine increased, indicating a decrease in the subjective value of cocaine. Compared with our previous delay-discounting experiment with immediate cocaine versus delayed food, both doses of delayed cocaine were discounted at a shallow rate. The present results demonstrate that rhesus monkeys will tolerate relatively long delays in an immediate-food versus delayed-drug situation, suggesting that in intertemporal choices between cocaine and food, the subjective value of cocaine is less affected by the delay until reinforcement than is the subjective value of delayed food. More generally, the present findings suggest that although drug abusers may choose impulsively when immediate drug reinforcement is available, they exercise self-control in the acquisition of a highly preferred, delayed drug reinforcer. (PsycINFO Database Record
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Affiliation(s)
- Sally L. Huskinson
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
| | - Joel Myerson
- Department of Psychological & Brain Sciences, Washington University, St. Louis, MO 63130
| | - Leonard Green
- Department of Psychological & Brain Sciences, Washington University, St. Louis, MO 63130
| | - James K. Rowlett
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216,Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433
| | - William L. Woolverton
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
| | - Kevin B. Freeman
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216
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24
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Choice between delayed food and immediate oxycodone in rats. Psychopharmacology (Berl) 2016; 233:3977-3989. [PMID: 27678551 PMCID: PMC5106336 DOI: 10.1007/s00213-016-4429-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/01/2016] [Indexed: 01/06/2023]
Abstract
RATIONALE The choice to seek immediate drug effects instead of more meaningful but delayed rewards is a defining feature of addiction. OBJECTIVES To develop a rodent model of this behavior, we allowed rats to choose between immediate intravenous delivery of the prescription opioid oxycodone (50 μg/kg) and delayed delivery of palatable food pellets. RESULTS Rats preferred food at delays up to 30 s, but they chose oxycodone and food equally at 60-s delay and preferred oxycodone over food at 120-s delay. Comparison of food-drug choice, food-only, and drug-only conditions indicated that food availability decreased drug intake, but drug availability increased food intake. In the food-only condition, food was effective as a reinforcer even when delayed by 120 s. Pre-session feeding with chow slowed acquisition of food and drug self-administration, but did not affect choice. To establish procedures for testing potential anti-addiction medications, noncontingent pre-treatment with oxycodone or naltrexone (analogous to substitution and antagonist therapies, respectively) were tested on a baseline in which oxycodone was preferred over delayed food. Naltrexone pre-treatment decreased drug intake and increased food intake. Oxycodone pre-treatment decreased drug intake, but also produced extended periods with no food or drug responding. CONCLUSIONS These findings show that the contingencies that induce preference for drugs over more meaningful but less immediate rewards in humans can be modeled in rodents, and they suggest that the model could be useful for assessing the therapeutic potential of treatments and exploring the underlying behavioral and neural mechanisms involved in addiction.
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25
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Development of a translational model to screen medications for cocaine use disorder II: Choice between intravenous cocaine and money in humans. Drug Alcohol Depend 2016; 165:111-9. [PMID: 27269368 PMCID: PMC4939714 DOI: 10.1016/j.drugalcdep.2016.05.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/22/2016] [Accepted: 05/02/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND A medication for treating cocaine use disorder has yet to be approved. Laboratory-based evaluation of candidate medications in animals and humans is a valuable means to demonstrate safety, tolerability and initial efficacy of potential medications. However, animal-to-human translation has been hampered by a lack of coordination. Therefore, we designed homologous cocaine self-administration studies in rhesus monkeys (see companion article) and human subjects in an attempt to develop linked, functionally equivalent procedures for research on candidate medications for cocaine use disorder. METHODS Eight (N=8) subjects with cocaine use disorder completed 12 experimental sessions in which they responded to receive money ($0.01, $1.00 and $3.00) or intravenous cocaine (0, 3, 10 and 30mg/70kg) under independent, concurrent progressive-ratio schedules. Prior to the completion of 9 choice trials, subjects sampled the cocaine dose available during that session and were informed of the monetary alternative value. RESULTS The allocation of behavior varied systematically as a function of cocaine dose and money value. Moreover, a similar pattern of cocaine choice was demonstrated in rhesus monkeys and humans across different cocaine doses and magnitudes of the species-specific alternative reinforcers. The subjective and cardiovascular responses to IV cocaine were an orderly function of dose, although heart rate and blood pressure remained within safe limits. CONCLUSIONS These coordinated studies successfully established drug versus non-drug choice procedures in humans and rhesus monkeys that yielded similar cocaine choice behavior across species. This translational research platform will be used in future research to enhance the efficiency of developing interventions to reduce cocaine use.
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Lamb RJ, Maguire DR, Ginsburg BC, Pinkston JW, France CP. Determinants of choice, and vulnerability and recovery in addiction. Behav Processes 2016; 127:35-42. [PMID: 27083500 DOI: 10.1016/j.beproc.2016.04.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/13/2022]
Abstract
Addiction may be viewed as choice governed by competing contingencies. One factor impacting choice, particularly as it relates to addiction, is sensitivity to delayed rewards. Discounting of delayed rewards influences addiction vulnerability because of competition between relatively immediate gains of drug use, e.g. intoxication, versus relatively remote gains of abstinence, e.g. family stability. Factors modifying delay sensitivity can be modeled in the laboratory. For instance, increased delay sensitivity can be similarly observed in adolescent humans and non-human animals. Similarly, genetic factors influence delay sensitivity in humans and animals. Recovery from addiction may also be viewed as choice behavior. Thus, reinforcing alternative behavior facilitates recovery because reinforcing alternative behavior decreases the frequency of using drugs. How reinforcing alternative behavior influences recovery can also be modeled in the laboratory. For instance, relapse risk decreases as abstinence duration increases, and this decreasing risk can be modeled in animals using choice procedures. In summary, addiction in many respects can be conceptualized as a problem of choice. Animal models of choice disorders stand to increase our understanding of the core processes that establish and maintain addiction and serve as a proving ground for development of novel treatments.
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Affiliation(s)
- R J Lamb
- University of Texas Health Science Center at San Antonio, Department of Psychiatry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States; University of Texas Health Science Center at San Antonio, Departments of Pharmacology, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States.
| | - David R Maguire
- University of Texas Health Science Center at San Antonio, Departments of Pharmacology, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States.
| | - Brett C Ginsburg
- University of Texas Health Science Center at San Antonio, Department of Psychiatry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States; University of Texas Health Science Center at San Antonio, Departments of Pharmacology, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States.
| | - Jonathan W Pinkston
- University of Texas Health Science Center at San Antonio, Department of Psychiatry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States; University of North Texas, Department of Behavioral Analysis, 360 G Chilton Hall, Avenue C, Denton TX 76208, United States.
| | - Charles P France
- University of Texas Health Science Center at San Antonio, Department of Psychiatry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States; University of Texas Health Science Center at San Antonio, Departments of Pharmacology, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States.
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27
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Vanderveldt A, Oliveira L, Green L. Delay discounting: Pigeon, rat, human--does it matter? JOURNAL OF EXPERIMENTAL PSYCHOLOGY-ANIMAL LEARNING AND COGNITION 2016; 42:141-62. [PMID: 26881899 DOI: 10.1037/xan0000097] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Delay discounting refers to the decrease in subjective value of an outcome as the time to its receipt increases. Across species and situations, animals discount delayed rewards, and their discounting is well-described by a hyperboloid function. The current review begins with a comparison of discounting models and the procedures used to assess delay discounting in nonhuman animals. We next discuss the generality of discounting, reviewing the effects of different variables on the degree of discounting delayed reinforcers by nonhuman animals. Despite the many similarities in discounting observed between human and nonhuman animals, several differences have been proposed (e.g., the magnitude effect; nonhuman animals discount over a matter of seconds whereas humans report willing to wait months, if not years before receiving a reward), raising the possibility of fundamental species differences in intertemporal choice. After evaluating these differences, we discuss delay discounting from an adaptationist perspective. The pervasiveness of discounting across species and situations suggests it is a fundamental process underlying decision making.
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Affiliation(s)
| | - Luís Oliveira
- Department of Psychological and Brain Sciences, Washington University
| | - Leonard Green
- Department of Psychological and Brain Sciences, Washington University
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28
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Moeller SJ, Stoops WW. Cocaine choice procedures in animals, humans, and treatment-seekers: Can we bridge the divide? Pharmacol Biochem Behav 2015; 138:133-41. [PMID: 26432174 DOI: 10.1016/j.pbb.2015.09.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/22/2015] [Accepted: 09/27/2015] [Indexed: 10/23/2022]
Abstract
Individuals with cocaine use disorder chronically self-administer cocaine to the detriment of other rewarding activities, a phenomenon best modeled in laboratory drug-choice procedures. These procedures can evaluate the reinforcing effects of drugs versus comparably valuable alternatives under multiple behavioral arrangements and schedules of reinforcement. However, assessing drug-choice in treatment-seeking or abstaining humans poses unique challenges: for ethical reasons, these populations typically cannot receive active drugs during research studies. Researchers have thus needed to rely on alternative approaches that approximate drug-choice behavior or assess more general forms of decision-making, but whether these alternatives have relevance to real-world drug-taking that can inform clinical trials is not well-understood. In this mini-review, we (A) summarize several important modulatory variables that influence cocaine choice in nonhuman animals and non-treatment seeking humans; (B) discuss some of the ethical considerations that could arise if treatment-seekers are enrolled in drug-choice studies; (C) consider the efficacy of alternative procedures, including non-drug-related decision-making and 'simulated' drug-choice (a choice is made, but no drug is administered) to approximate drug choice; and (D) suggest opportunities for new translational work to bridge the current divide between preclinical and clinical research.
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Affiliation(s)
- Scott J Moeller
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - William W Stoops
- Department of Behavioral Science and Center on Drug and Alcohol Research, University of Kentucky College of Medicine, Lexington, KY, United States; Department of Psychiatry, University of Kentucky College of Medicine, Lexington, KY, United States; Department of Psychology, University of Kentucky College of Arts and Sciences, Lexington, KY, United States.
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