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Paine TA, Pierotti C, Swanson ES, Martin Del Campo Z, Kulkarni S, Zhang J. Sex, but not juvenile stress, affects reversal learning and DRL performance following cocaine administration. Pharmacol Biochem Behav 2023; 231:173634. [PMID: 37717823 DOI: 10.1016/j.pbb.2023.173634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/24/2023] [Accepted: 09/12/2023] [Indexed: 09/19/2023]
Abstract
INTRODUCTION Early adversity, impulsivity and sex all contribute to the risk of developing substance use disorder. Using rats, we examined how juvenile stress interacts with sex and cocaine to affect performance on a serial reversal task and a differential reinforcement of low rates 10 s (DRL10) task. The expression of dopamine-related proteins in several brain areas was also assessed. METHODS From postnatal days (PND) 25-29, rats were exposed to a variable stress protocol. In adulthood, rats were trained on the reversal task and the effects of cocaine (0, 10, or 20 mg/kg, IP) on performance were assessed. Next, rats were trained on the DRL10 task and the effects of cocaine on performance were assessed. Finally, brains were extracted, and Western blot analyses conducted. RESULTS Juvenile stress did not affect behavior. Sex did not affect baseline performance in either task. In the reversal task, cocaine decreased % high probability responses and the number of rewards earned in both sexes. Cocaine had sex-dependent effects on omissions, low probability responses and response latencies. In the DRL10 task, cocaine decreased the peak latency to respond and the number of rewards earned in both sexes. Cocaine had sex-dependent effects on peak rate of responding, response efficiency, burst responses and long responses. Female rats exhibited increased expression of DRD1 receptors in the striatum. DISCUSSION These data contribute to the growing literature demonstrating sex differences in the behavioral effects of cocaine and suggest that DRD1 receptors could contribute to the observed behavioral sex differences.
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Affiliation(s)
- Tracie A Paine
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America.
| | - Caroline Pierotti
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America
| | - Evan S Swanson
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America
| | - Zoë Martin Del Campo
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America
| | - Sydney Kulkarni
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America
| | - Jeffrey Zhang
- Department of Neuroscience, Oberlin College, Oberlin, OH 44074, United States of America
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Survey on the Past Decade of Technology in Animal Enrichment: A Scoping Review. Animals (Basel) 2022; 12:ani12141792. [PMID: 35883339 PMCID: PMC9311579 DOI: 10.3390/ani12141792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/04/2022] [Accepted: 06/15/2022] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Enrichment is important for supporting the well-being of captive animals. Enrichment increase animal quality of life through encouraging natural behaviours. As enrichment is shifting to a more centered role in animal care, technology is becoming increasingly accessible and is becoming embedded in animal enrichment in creative ways. This review explores the trends in technology usage in animal enrichment studies. Through pulling the past decade of technology enrichment work together, we discuss gaps such as needing to include a larger variety of species (extending passed mammals), ensuring enrichment designs focus primarily on the senses an animal uses to interact with the world rather than human senses, and encouraging similar study designs across animal contexts to allow for streamlined comparisons. Abstract Environmental enrichment is adding complexity to an environment that has a positive impact on a captive animal as a necessity of care. Computing technology is being rapidly weaved throughout the space in both enrichment devices as well as evaluating enrichment outcomes. In this article, we present a scoping review of 102 captive animal enrichment studies and propose a contextual lens for exploring current practices. We discuss the importance of directed growth in species inclusion, transitioning beyond anthro-centric designs, and utilizing shared methodologies.
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Garnham LC, Clarke C, Løvlie H. How Inhibitory Control Relates to Positive and Negative Affective States in Red Junglefowl. Front Vet Sci 2022; 9:872487. [PMID: 35464350 PMCID: PMC9024352 DOI: 10.3389/fvets.2022.872487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/16/2022] [Indexed: 12/12/2022] Open
Abstract
Individual differences in inhibitory control, an aspect of cognition, are found in many species. How this variation links to affective states is not much explored, and could be relevant for welfare. As less fearful, more optimistic, individuals may act more impulsively, inhibitory control could link to less negative, more positive, affective states. Alternatively, poorer inhibitory control could associate with more negative, less positive, affective states, as poorer inhibitory control can result in individuals being less able to adapt to changing environments and more likely to show stereotypies. We here explored in three cohorts (N = 209) of captive red junglefowl, the ancestor of domestic chickens, how inhibitory control associated with affective states. Specifically, we measured inhibitory control with a detour task, and negative and positive affective states with a tonic immobility test and a cognitive judgement bias test, respectively. Cognition and behaviour can differ between ages and sexes. Therefore, we investigated how inhibitory control related to affective states in younger chicks (≈2.5 weeks old), older chicks (≈5 weeks old) and sexually mature adults (≈28 weeks old) of both sexes. In younger chicks, poorer inhibitory control associated with less negative, more positive, affective states. We found no relationship between inhibitory control and affective states in older chicks or adults, nor sex differences regarding how inhibitory control related to affective states. Overall, our results suggest that inhibitory control can link to affective states and that the nature of these links can change over ontogeny.
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Affiliation(s)
- Laura Clare Garnham
- Division of Biology, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Charlie Clarke
- Division of Biology, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
- School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Hanne Løvlie
- Division of Biology, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
- *Correspondence: Hanne Løvlie
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Salinas-Velarde ID, Bernal-Morales B, Pacheco-Cabrera P, Sánchez-Aparicio P, Pascual-Mathey LI, Venebra-Muñoz A. Lower ΔFosB expression in the dopaminergic system after stevia consumption in rats housed under environmental enrichment conditions. Brain Res Bull 2021; 177:172-180. [PMID: 34624462 DOI: 10.1016/j.brainresbull.2021.10.001] [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: 05/23/2021] [Revised: 09/12/2021] [Accepted: 10/01/2021] [Indexed: 10/20/2022]
Abstract
Environmental enrichment (EE) has been proven to reduce drug seeking and the development of addiction-related behaviors in rodent models, but the effects of EE on natural reward acquisition in the form of sweet beverages are poorly understood. Accumulating evidence shows that the intake of sugar, the main ingredient of sweet beverages, alters the dopaminergic system, leading to addiction-related physiological and molecular changes. Sugar in sweet beverages has been replaced with natural sweeteners, such as stevia extract, which has greater sweetener potential but no energy content. Our research group found that sucralose consumption increased the expression of ΔFosB in reward-related nuclei, suggesting activation of the dopaminergic system. The present study assessed the effects of EE on stevia consumption and the expression of ΔFosB in the nucleus accumbens, caudate putamen, and prefrontal cortex. Sixteen male Wistar rats, 21 days old, were randomly assigned to an EE group (n = 8) or standard environment (SE) group (n = 8) and reared for 30 days. On postnatal day 52 (PND52), the brains of four animals in each housing condition were extracted to determine basal ΔFosB levels. Stevia consumption with intermittent access and ΔFosB immunoreactivity were measured for 21 days in the remainder of the rats. Compared with SE animals, EE animals exhibited a reduction of stevia consumption and alterations of ΔFosB immunoreactivity in the reward system. These results indicate that EE reduces stevia consumption and the stevia-induced ΔFosB expression, suggesting addiction-related changes in dopaminergic nuclei, which may be interpreted as a neuroprotective effect.
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Affiliation(s)
- I Daniel Salinas-Velarde
- Laboratory of Neurobiology of Addiction and Brain Plasticity, Faculty of Sciences, Universidad Autónoma del Estado de México, State of Mexico, Mexico.
| | - Blandina Bernal-Morales
- Laboratory of Neuropharmacology, Institute for Neuroethology, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
| | - Pablo Pacheco-Cabrera
- Institute for Biomedical Research, Department of Cell Biology and Physiology, Universidad Nacional Autónoma de México, Mexico City, Mexico; Institute for Neuroethology, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
| | - Pedro Sánchez-Aparicio
- School of Veterinary Medicine and Zootechnics, Universidad Autónoma del Estado de México, Mexico.
| | - Luz I Pascual-Mathey
- School of Pharmaceutic Biological Chemistry, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
| | - Arturo Venebra-Muñoz
- Laboratory of Neurobiology of Addiction and Brain Plasticity, Faculty of Sciences, Universidad Autónoma del Estado de México, State of Mexico, Mexico.
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Ryding S, Garnham LC, Abbey-Lee RN, Petkova I, Kreshchenko A, Løvlie H. Impulsivity is affected by cognitive enrichment and links to brain gene expression in red junglefowl chicks. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Juvenile stress increases cocaine-induced impulsivity in female rats. Behav Brain Res 2021; 414:113488. [PMID: 34329670 DOI: 10.1016/j.bbr.2021.113488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022]
Abstract
In humans, adverse childhood experiences are associated with an increased risk of developing a neuropsychiatric disorder. Changes in social behavior and cognitive function are hallmarks of numerous neuropsychiatric disorders. Here we examined the effects of exposure to variable stress during the juvenile period on social behavior, reward, and cognitive function (as measured in the 5-choice serial reaction time task (5CSRTT)) in rats. From postnatal days (PND) 25-29 male and female rats were exposed to a variable stress protocol. In adulthood, social interactions and sucrose preference were assessed prior to training on the 5CSRTT. Once successfully trained, rats were challenged with different task versions, and then the effects of cocaine (0, 10, or 20 mg/kg, IP) on performance were assessed. A follow-up experiment examined the ability of the D2 receptor antagonist eticlopride (0.0, 0.025, 0.05 mg/kg, IP) to block the effects of cocaine on 5CSRTT performance in female rats. Male rats exposed to juvenile stress tended to engage in less social behavior and had an increased correct response latency in the 5CSRTT following cocaine administration. Female rats exposed to juvenile stress exhibited a trend towards increased social behavior and demonstrated increased cocaine-induced impulsivity. The increase in impulsivity was not blocked by co-administration of eticlopride. Juvenile stress had minimal effects on adult behavior in male rats, but increased cocaine-induced impulsivity in female rats. Such an effect could contribute to the enhanced escalation of drug-use observed in females that experience juvenile stress. This possibility awaits further testing.
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Esteves M, Moreira PS, Sousa N, Leite-Almeida H. Assessing Impulsivity in Humans and Rodents: Taking the Translational Road. Front Behav Neurosci 2021; 15:647922. [PMID: 34025369 PMCID: PMC8134540 DOI: 10.3389/fnbeh.2021.647922] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/29/2021] [Indexed: 12/28/2022] Open
Abstract
Impulsivity is a multidimensional construct encompassing domains of behavioral inhibition as well as of decision making. It is often adaptive and associated with fast responses, being in that sense physiological. However, abnormal manifestations of impulsive behavior can be observed in contexts of drug abuse and attention-deficit/hyperactivity disorder (ADHD), among others. A number of tools have therefore been devised to assess the different facets of impulsivity in both normal and pathological contexts. In this narrative review, we systematize behavioral and self-reported measures of impulsivity and critically discuss their constructs and limitations, establishing a parallel between assessments in humans and rodents. The first rely on paradigms that are typically designed to assess a specific dimension of impulsivity, within either impulsive action (inability to suppress a prepotent action) or impulsive choice, which implies a decision that weighs the costs and benefits of the options. On the other hand, self-reported measures are performed through questionnaires, allowing assessment of impulsivity dimensions that would be difficult to mimic in an experimental setting (e.g., positive/negative urgency and lack of premeditation) and which are therefore difficult (if not impossible) to measure in rodents.
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Affiliation(s)
- Madalena Esteves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center - Braga, Braga, Portugal
| | - Pedro Silva Moreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center - Braga, Braga, Portugal.,Psychological Neuroscience Lab, CIPsi, School of Psychology, University of Minho, Braga, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center - Braga, Braga, Portugal
| | - Hugo Leite-Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clinical Academic Center - Braga, Braga, Portugal
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Early environmental enrichment and impoverishment differentially affect addiction-related behavioral traits, cocaine-taking, and dopamine D 2/3 receptor signaling in a rat model of vulnerability to drug abuse. Psychopharmacology (Berl) 2021; 238:3543-3557. [PMID: 34463825 PMCID: PMC8629910 DOI: 10.1007/s00213-021-05971-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/23/2021] [Indexed: 11/03/2022]
Abstract
RATIONALE Risk factors for drug addiction include genetics, environment, and behavioral traits such as impulsivity and novelty preference (NP), which have been related to deficits in striatal dopamine (DA) D2/3-receptors (D2/3R) and heightened amphetamine (AMPH)-induced DA release. However, the influence of the early rearing environment on these behavioral and neurochemical variables is not clear. OBJECTIVES We investigated the influence of early rearing environment on striatal D2/3R availabilities and AMPH-induced DA release in relation to impulsivity, NP, and propensity to drug self-administration (SA) in "addiction-prone" Roman high- (RHA) and "addiction-resistant" Roman low-avoidance (RLA) rats. METHODS Animals were reared post-weaning in either environmental enrichment (EE) or impoverishment (EI) and were assessed at adulthood for impulsivity, NP, and propensity to cocaine SA. EE and EI rats were also scanned using single-photon emission computed tomography to concurrently measure in vivo striatal D2/3R availability and AMPH-induced DA release. RESULTS EE vs. EI was associated with heightened impulsivity and a lack of NP in both rat lines. Higher dorsal striatal D2/3R densities were found in RHA EE and higher AMPH-induced DA release in RLA EE. Both impulsivity and NP were negatively correlated to dorsal striatal D2/3R availabilities and positively correlated with AMPH-induced DA release in EI but not in EE. EE vs. EI was related to a faster rate of cocaine intake and elevated active timeout responses in RHAs. CONCLUSION Our results suggest non-monotonic, environment-dependent, relationships between impulsivity, NP, and D2/3R-mediated signaling, and suggest that EI vs. EE may decrease the reinforcing effects of psychostimulants in predisposed individuals.
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Wukitsch TJ, Moser TJ, Brase EC, Kiefer SW, Cain ME. Adolescent ethanol exposure and differential rearing environment affect taste reactivity to ethanol in rats. Alcohol 2020; 89:113-122. [PMID: 32937167 DOI: 10.1016/j.alcohol.2020.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 12/20/2022]
Abstract
The identification and characterization of variables that influence "liking" and enhance vulnerability to repeated alcohol use are vital to understanding and treating alcohol use disorders. In the current study, we explore the influence of rearing environment and experimenter-administered adolescent ethanol on the hedonic value of ethanol, sucrose, and quinine. Male and female rats were reared for 30 days starting at postnatal day (PND) 21 in either an enriched, isolated, or standard condition and received 1.5 g/kg (intraperitoneally [i.p.]) 20% (w/v) ethanol or saline every other day for 12 days starting at PND 28. Thereafter, all rats had indwelling intraoral fistulae implanted and their taste reactivities to water, ethanol (5, 10, 20, 30, 40% v/v), sucrose (0.1, 0.25, 0.5 M), and quinine (0.1, 0.5 mM) were recorded and analyzed. Results indicated that enrichment elevated hedonic responding to sucrose compared to isolation, and induced a stronger negative relationship between hedonic responding and ethanol concentration compared to standard conditions. Enrichment also elevated aversive responding to ethanol and quinine compared to both isolated and standard condition rats. Adolescent ethanol injections marginally reduced aversive responding to quinine. These results replicate previous findings that environmental enrichment enhances both "liking" and aversion. In addition, the current findings suggest that, while adolescent ethanol injections may blunt aversive responses to quinine, they have no effect on aversive or hedonic responding to ethanol or sucrose. Together with existing literature, our results may suggest that experience with the taste of ethanol is necessary for alterations to ethanol "liking" and aversion.
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Wukitsch TJ, Brase EC, Moser TJ, Kiefer SW, Cain ME. Differential rearing alters taste reactivity to ethanol, sucrose, and quinine. Psychopharmacology (Berl) 2020; 237:583-597. [PMID: 31832722 PMCID: PMC7747299 DOI: 10.1007/s00213-019-05394-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 11/08/2019] [Indexed: 12/23/2022]
Abstract
RATIONALE Early-life environment influences reinforcer and drug motivation in adulthood; however, the impact on specific components of motivation, including hedonic value ("liking"), remains unknown. OBJECTIVES The current study determined whether differential rearing alters liking and aversive responding to ethanol, sucrose, and quinine in an ethanol-naïve rat model. METHODS Male and female rats were reared for 30 days starting at postnatal day 21 in either an enriched (EC), isolated (IC), or standard condition (SC). Thereafter, all rats had indwelling intraoral fistulae implanted and their taste reactivity to water, ethanol (5, 10, 20, 30, 40% v/v), sucrose (0.1, 0.25, 0.5 M), and quinine (0.1, 0.5 mM) was recorded and analyzed. RESULTS EC rats had higher amounts of liking responses to ethanol, sucrose, and quinine and higher amounts of aversive responses to ethanol and quinine compared to IC rats. While EC and IC rats' responses were different from each other, they both tended to be similar to SCs, who fell in between the EC and IC groups. CONCLUSIONS These results suggest that environmental enrichment may enhance sensitivity to a variety of tastants, thereby enhancing liking, while isolation may dull sensitivity, thereby dulling liking. Altogether, the evidence suggests that isolated rats have a shift in the allostatic set-point which may, in part, drive increased responding for a variety of rewards including ethanol and sucrose. Enriched rats have enhanced liking of both sucrose and ethanol suggesting that enrichment may offer a unique phenotype with divergent preferences for incentive motivation.
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Affiliation(s)
- Thomas J. Wukitsch
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, 1114 Mid-Campus Dr N, Manhattan, KS 66506-5302, USA
| | - Emma C. Brase
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, 1114 Mid-Campus Dr N, Manhattan, KS 66506-5302, USA
| | - Theodore J. Moser
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, 1114 Mid-Campus Dr N, Manhattan, KS 66506-5302, USA
| | - Stephen W. Kiefer
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, 1114 Mid-Campus Dr N, Manhattan, KS 66506-5302, USA
| | - Mary E. Cain
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, 1114 Mid-Campus Dr N, Manhattan, KS 66506-5302, USA
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Therapeutic efficacy of environmental enrichment for substance use disorders. Pharmacol Biochem Behav 2019; 188:172829. [PMID: 31778722 DOI: 10.1016/j.pbb.2019.172829] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/18/2022]
Abstract
Addiction to drug and alcohol is regarded as a major health problem worldwide for which available treatments show limited effectiveness. The biggest challenge remains to enhance the capacities of interventions to reduce craving, prevent relapse and promote long-term recovery. New strategies to meet these challenges are being explored. Findings from preclinical work suggest that environmental enrichment (EE) holds therapeutic potential for the treatment of substance use disorders, as demonstrated in a number of animal models of drug abuse. The EE intervention introduced after drug exposure leads to attenuation of compulsive drug taking, attenuation of the rewarding (and reinforcing) effects of drugs, reductions in control of behavior by drug cues, and, very importantly, relapse prevention. Clinical work also suggests that multidimensional EE interventions (involving physical activity, social interaction, vocational training, recreational and community involvement) might produce similar therapeutic effects, if implemented continuously and rigorously. In this review we survey preclinical and clinical studies assessing the efficacy of EE as a behavioral intervention for substance use disorders and address related challenges. We also review work providing empirical evidence for EE-induced neuroplasticity within the mesocorticolimbic system that is believed to contribute to the seemingly therapeutic effects of EE on drug and alcohol-related behaviors.
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Voluntary ethanol consumption during early social isolation and responding for ethanol in adulthood. Alcohol 2019; 77:1-10. [PMID: 30240808 DOI: 10.1016/j.alcohol.2018.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/06/2018] [Accepted: 09/12/2018] [Indexed: 11/23/2022]
Abstract
Little is known about the influence of rearing environments concurrent with voluntary intermittent access to ethanol on subsequent adult ethanol-related behaviors. Previous research has shown that adult rats reared in post-weaning, social isolation conditions (IC) respond more for operant ethanol compared to laboratory standard conditions (SC). Ethanol-exposed adolescents tend to consume more ethanol in adulthood than rats exposed as adults. The current study examined voluntary ethanol consumption during adolescence between IC and SC rats, subsequent operant responding for ethanol, and extinction of responding in the same rats as adults. Differences in ethanol metabolism may alter the amount of reward value per unit of ethanol consumed. Therefore, the current study also examined blood ethanol concentrations (BEC) between IC rats and SC rats. Ethanol-naïve Long-Evans rats arrived in the lab at postnatal day (PND) 21 and were separated into either IC or SC where they remained for the duration of the experiments. On PND 27, rats received intermittent access to 20% ethanol (3 days/week) for 4 or 6 weeks. Rats in the 6-week cohort were then trained to lever press for 20% ethanol in 30-min sessions followed by extinction. A separate cohort was reared in IC or SC, injected with 1.5 or 3.0 g/kg of ethanol (intraperitoneally [i.p.]), followed by BEC measurement. Overall, IC rats had higher ethanol preference and consumption during adolescence/early adulthood. IC and SC rats did not differ in their rates of operant responding for ethanol, and SC rats responded more than IC rats during extinction. There were no differences in BEC between IC and SC rats. These findings highlight the importance of the environment during rat adolescent development with isolation conditions increasing binge-like drinking and ethanol preference after 3-4 weeks without differences in metabolism as a potential factor. Additionally, the findings indicate that intermittent adolescent access to ethanol may change typical differences in operant responding patterns between IC and SC rats in adulthood.
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Frankowska M, Miszkiel J, Pomierny-Chamioło L, Pomierny B, Giannotti G, Suder A, Filip M. Alternation in dopamine D 2-like and metabotropic glutamate type 5 receptor density caused by differing housing conditions during abstinence from cocaine self-administration in rats. J Psychopharmacol 2019; 33:372-382. [PMID: 30644313 DOI: 10.1177/0269881118821113] [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: 12/12/2022]
Abstract
BACKGROUND Environmental conditions have an important function in substance use disorder, increasing or decreasing the risks of relapse. Several studies strongly support the role of the dopamine D2-like and metabotropic glutamate type 5 receptors in maladaptive neurobiological responses to cocaine reward and relapse. AIMS The present study employed cocaine self-administration with yoked-triad procedure in rats to explore whether drug abstinence in different housing conditions affects the drug-seeking behaviour and the dopamine D2-like and metabotropic glutamate type 5 receptor density and affinity in several regions of the animal brain. METHODS Rats were trained to self-administer cocaine and later they were forced to abstain either in: (a) enriched environment or (b) isolation cage conditions to evaluate the effect of housing conditions on the drug-seeking behaviour and to assess changes concerning receptors in animals brain. RESULTS Our results show that exposure to enriched environment conditions strongly reduced active lever presses during cue-induced drug-seeking. At the neurochemical level, we demonstrated a significant increase in the dopamine D2-like receptor density in the prefrontal cortex in animals following drug abstinence in isolation cage or enriched environment conditions, and the reduction in their density in the dorsal striatum provoked by isolation cage conditions. The metabotropic glutamate type 5 receptor density decreased only in the prefrontal cortex after isolation cage and enriched environment abstinence. CONCLUSIONS This study shows the different impacts caused by the type of housing conditions during abstinence from cocaine self-administration on drug-seeking behaviour in rats. The observed changes in the dopamine D2-like and metabotropic glutamate type 5 receptor Bmax and/or Kd values were brain-region specific and related to either pharmacological and/or motivational features of cocaine.
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Affiliation(s)
- Małgorzata Frankowska
- 1 Department of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Joanna Miszkiel
- 1 Department of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Lucyna Pomierny-Chamioło
- 2 Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Collegium Medicum, Kraków, Poland
| | - Bartosz Pomierny
- 2 Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Collegium Medicum, Kraków, Poland
| | - Giuseppe Giannotti
- 3 Department of Pharmacological and Bimolecular Sciences, University of Milan, Milan, Italy
| | - Agata Suder
- 1 Department of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Małgorzata Filip
- 1 Department of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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An automated home-cage-based 5-choice serial reaction time task for rapid assessment of attention and impulsivity in rats. Psychopharmacology (Berl) 2019; 236:2015-2026. [PMID: 30826849 PMCID: PMC6647605 DOI: 10.1007/s00213-019-05189-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 02/04/2019] [Indexed: 11/01/2022]
Abstract
RATIONALE The 5-choice serial reaction time task (5-CSRTT) is a widely used operant task for measuring attention and motor impulsivity in rodents. Training animals in this task requires an extensive period of daily operant sessions. Recently, a self-paced, automated version of this task has been developed for mice, which substantially reduces training time. Whether a similar approach is effective for rats is currently unknown. OBJECTIVE Here, we tested whether attention and impulsivity can be assessed in rats with a self-paced version of the 5-CSRTT. METHODS Operant boxes were connected to home-cages with tunnels. Two groups of rats self-paced their training by means of an automated script. The first group of animals was allowed unlimited access (UA) to start trials in the task; for the second group, trial availability was restricted to the first 2.5 h of the dark cycle (TR). Task parameter manipulations, such as variable inter-trial intervals and stimulus durations as well as pharmacological challenges with scopolamine, were tested to validate the task. RESULTS Self-paced training took less than 1 week. Animals in the UA group showed higher levels of omissions compared with the TR group. In both protocols, variable inter-trial intervals increased impulsivity, and variable stimulus durations decreased attentional performance. Scopolamine affected cognitive performance in the TR group only. CONCLUSIONS Home-cage-based training of the 5-CSRTT in rats, especially the TR protocol, presents a valid and fast alternative for measuring attention and impulsivity.
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Rung JM, Madden GJ. Experimental reductions of delay discounting and impulsive choice: A systematic review and meta-analysis. J Exp Psychol Gen 2018; 147:1349-1381. [PMID: 30148386 DOI: 10.1037/xge0000462] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Many behaviors posing significant risks to public health are characterized by repeated decisions to forego better long-term outcomes in the face of immediate temptations. Steeply discounting the value of delayed outcomes often underlies a pattern of impulsive choice. Steep delay discounting is correlated with addictions (e.g., substance abuse, obesity) and behaviors such as seatbelt use and risky sexual activity. As evidence accumulates suggesting steep delay discounting plays a causal role in these maladaptive behaviors, researchers have begun testing methods for reducing discounting. In this first systematic and comprehensive review of this literature, the findings of 92 articles employing different methodologies to reduce discounting are evaluated narratively and meta-analytically. Although most of the methods reviewed produced significant reductions in discounting, they varied in effect sizes. Most methods were ideal for influencing one-off choices (e.g., framing and priming manipulations), although other successful manipulations, such as episodic future thinking, could be incorporated into existing therapies designed to produce longer-lasting changes in decision-making. The largest and longest-lasting effects were produced by learning-based manipulations, although translational research is needed to determine the generality and clinical utility of these methods. Methodological shortcomings in the existing literature and suggestions for ameliorating these issues are discussed. This review reveals a variety of methods with translational potential, which, through continued refinement, may prove effective in reducing impulsive choice and its associated maladaptive decisions that negatively impact quality of life. (PsycINFO Database Record
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Abstract
Impulsive choice underlies several psychological disorders and can be assessed in laboratory rats using delay-discounting tasks, in which choice is for either one food pellet immediately or three food pellets after a delay. Choice for the smaller, immediate reinforcer is considered the impulsive choice. Lewis (LEW) and Fischer 344 (F344) rats differ in the number of impulsive choices made during this task when singly housed, with LEW choosing the impulsive option more often. Due to increasing recommendations to provide environmental enrichment as a component of animal-husbandry practices, a systematic replication of two previous studies was conducted using pair-housed LEW and F344. Delay discounting was assessed with pair-housed LEW and F344 and compared to previous data from singly housed LEW and F344 collected from the same laboratory. Results showed that differences in impulsive choice between the two strains were attenuated with pair housing. The main result driving this change appears to be an increase in impulsive choice in pair-housed F344 relative to singly housed F344.
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Steele CC, Pirkle JRA, Kirkpatrick K. Diet-induced impulsivity: Effects of a high-fat and a high-sugar diet on impulsive choice in rats. PLoS One 2017; 12:e0180510. [PMID: 28662133 PMCID: PMC5491254 DOI: 10.1371/journal.pone.0180510] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/18/2017] [Indexed: 11/19/2022] Open
Abstract
Impulsive choice is a common charactertistic among individuals with gambling problems, obesity, and substance abuse issues. Impulsive choice has been classified as a trans-disease process, and understanding the etiology of trait impulsivity could help to understand how diseases and disorders related to impulsive choice are manifested. The Western diet is a possible catalyst of impulsive choice as individuals who are obese and who eat diets high in fat and sugar are typically more impulsive. However, such correlational evidence is unable to discern the direction and causal nature of the relationship. The present study sought to determine how diet may directly contribute to impulsive choice. After 8 weeks of dietary exposure (high-fat, high-sugar, chow), the rats were tested on an impulsive choice task, which presented choices between a smaller-sooner reward (SS) and a larger-later reward (LL). Then, the rats were transferred to a chow diet and retested on the impulsive choice task. The high-sugar and high-fat groups made significantly more impulsive choices than the chow group. Both groups became more self-controlled when they were off the diet, but there were some residual effects of the diet on choice behavior. These results suggest that diet, specifically one high in processed fat or sugar, induces impulsive choice. This diet-induced impulsivity could be a precursor to other disorders that are characterized by impulsivity, such as diet-induced obesity, and could offer potential understanding of the trans-disease nature of impulsive choice.
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Affiliation(s)
- Catherine C. Steele
- Department of Psychological Sciences, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
| | - Jesseca R. A. Pirkle
- Department of Psychological Sciences, Kansas State University, Manhattan, Kansas, United States of America
| | - Kimberly Kirkpatrick
- Department of Psychological Sciences, Kansas State University, Manhattan, Kansas, United States of America
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Differential effects of social and novelty enrichment on individual differences in impulsivity and behavioral flexibility. Behav Brain Res 2017; 327:54-64. [PMID: 28341610 DOI: 10.1016/j.bbr.2017.03.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/10/2017] [Accepted: 03/20/2017] [Indexed: 01/03/2023]
Abstract
Early life experience profoundly impacts behavior and cognitive functions in rats. The present study investigated how the presence of conspecifics and/or novel objects, could independently influence individual differences in impulsivity and behavioral flexibility. Twenty-four rats were reared in an isolated condition, an isolated condition with a novel object, a pair-housed social condition, or a pair-housed social condition with a novel object. The rats were then tested on an impulsive choice task, a behavioral flexibility task, and an impulsive action task. Novelty enrichment produced an overall increase in impulsive choice, while social enrichment decreased impulsive choice in the absence of novelty enrichment and also produced an overall increase in impulsive action. In the behavioral flexibility task, social enrichment increased regressive errors, whereas both social and novelty enrichment reduced never-reinforced errors. Individual differences analyses indicated a significant relationship between performance in the behavioral flexibility and impulsive action tasks, which may reflect a common psychological correlate of action inhibition. Moreover, there was a relationship between delay sensitivity in the impulsive choice task and performance on the DRL and behavioral flexibility tasks, suggesting a dual role for timing and inhibitory processes in driving the interrelationship between these tasks. Overall, these results indicate that social and novelty enrichment produce distinct effects on impulsivity and adaptability, suggesting the need to parse out the different elements of enrichment in future studies. Further research is warranted to better understand how individual differences in sensitivity to enrichment affect individuals' interactions with and the resulting consequences of the rearing environment.
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Glueck E, Ginder D, Hyde J, North K, Grimm JW. Effects of dopamine D1 and D2 receptor agonists on environmental enrichment attenuated sucrose cue reactivity in rats. Psychopharmacology (Berl) 2017; 234:815-825. [PMID: 28032125 PMCID: PMC5891328 DOI: 10.1007/s00213-016-4516-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/17/2016] [Indexed: 12/25/2022]
Abstract
RATIONALE Acute or chronic environmental enrichment (EE) reduces sucrose cue reactivity in rats. This effect may be mediated by dopamine receptors. OBJECTIVES We examined whether dopamine D1 or D2 receptor agonism could reverse the EE effect. We also examined whether any reversal effects would vary with the incubation of sucrose craving. METHODS Following 10 days (2 h/day) of sucrose self-administration, rats experienced either 1 or 30 days of forced abstinence and either overnight (acute) or 29 day (chronic) EE. D1 (SKF 81297; 0, 0.3, or 1 mg/kg) or D2 (quinpirole; 0, 0.1, or 0.3 mg/kg) agonist was administered systemically immediately prior to a subsequent 2-h cue reactivity test the next day (n = 9-12 per group). RESULTS Dose-dependent effects were limited to the day 1 test. High doses of the agonists increased day 1 acute EE cue reactivity to levels comparable to control animals. On the day 30 test, SKF 81297 increased cue reactivity in acute EE, chronic EE, and control rats. In contrast, quinpirole resulted in similar cue reactivity for control and enriched rats, more from a reduction in responding by controls vs. a recovery of responding by EE-experienced rats. CONCLUSIONS Both D1 and D2 receptors may be involved in the acute EE-mediated decrease in cue reactivity observed following 1 day of forced abstinence. In contrast, at 30 days of forced abstinence, D1 receptors may be critical in cue reactivity as SKF 81297 was effective at both restoring responding of enriched animals and potentiating responding of controls.
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Affiliation(s)
- Edwin Glueck
- Department of Psychology and Program in Behavioral Neuroscience, Western Washington University, 516 High Street, Bellingham, WA 98225-9172, USA
| | - Darren Ginder
- Department of Psychology and Program in Behavioral Neuroscience, Western Washington University, 516 High Street, Bellingham, WA 98225-9172, USA
| | - Jeff Hyde
- Department of Psychology and Program in Behavioral Neuroscience, Western Washington University, 516 High Street, Bellingham, WA 98225-9172, USA
| | - Katherine North
- Department of Psychology and Program in Behavioral Neuroscience, Western Washington University, 516 High Street, Bellingham, WA 98225-9172, USA
| | - Jeffrey W. Grimm
- Department of Psychology and Program in Behavioral Neuroscience, Western Washington University, 516 High Street, Bellingham, WA 98225-9172, USA
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Liu YP, Wilkinson LS, Robbins TW. 'Waiting impulsivity' in isolation-reared and socially-reared rats: effects of amphetamine. Psychopharmacology (Berl) 2017; 234:1587-1601. [PMID: 28314950 PMCID: PMC5420383 DOI: 10.1007/s00213-017-4579-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 02/20/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Rats reared in social isolation exhibit various cognitive and behavioural abnormalities in adulthood. However, impulsivity following this treatment still remains unclear, especially in response to medications used in attention deficit hyperactivity disorder, such as amphetamine. METHODS Using an isolation-rearing (IR) manipulation, the present study examined the effects of IR on impulsive action and impulsive choice when also treated with doses of D-amphetamine, by employing the five-choice serial reaction time task (5-CSRTT) and a temporal discounting of reward task (TDRT), respectively. RESULTS IR rats showed similar acquisition of the 5-CSRTT. Amphetamine increased premature responding in both groups; however, IR rats showed less responding overall. For the TDRT, IR rats revealed a greater preference for the large but delayed reward during task acquisition (i.e. were less impulsive) with a higher rate of nose poking during the delay, and exhibited a compressed dose-response function (i.e. reduced dose sensitivity) for amphetamine. DISCUSSION Impulsive action and impulsive choice were reduced in IR rats under certain conditions, and a blunted response to D-amphetamine was found on these measures. These reductions in impulsivity contrast with locomotor hyperactivity normally shown in IR rats and the findings have implications for the utility of IR as a model of psychopathology.
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Affiliation(s)
- Yia-Ping Liu
- Laboratory of Cognitive Neuroscience, Departments of Physiology and Psychiatry, National Defense Medical Center, Taipei, 11490, Taiwan. .,Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK. .,Department of Psychiatry, University of Cambridge, Cambridge, CB2 0SZ, UK.
| | - Lawrence S. Wilkinson
- Behavioural Genetics Group, Schools of Psychology & Medicine, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT UK
| | - Trevor W. Robbins
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB UK ,Department of Psychology, University of Cambridge, Cambridge, CB2 3EB UK
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Robbins TW. Neurobehavioural sequelae of social deprivation in rodents revisited: Modelling social adversity for developmental neuropsychiatric disorders. J Psychopharmacol 2016; 30:1082-1089. [PMID: 27678088 DOI: 10.1177/0269881116664450] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The significance of investigating effects of deprivation of social experience in rodents is reviewed in the context of the review by Robbins et al. (1996) in the Journal of Psychopharmacology (10: 39-47). The early development of the paradigm by which rats were reared post-weaning in social isolation is described and compared with other early experience manipulations. The specification of the neural and behavioural phenotype of the isolate is brought up-to-date, focusing on changes in motivation and cognitive function, as well as on contrasting changes in the dopamine and serotonin systems, and in cortical (including hippocampal) structure and function. The relevance of the isolate for animal models of psychiatric disorders such as attention deficit hyperactivity disorder and schizophrenia is reviewed, and it is considered that the paradigm best exemplifies a manipulation that can be applied to test effects of certain forms of social adversity during adolescence on brain development and behaviour.
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Affiliation(s)
- T W Robbins
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
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Laude JR, Daniels CW, Wade JC, Zentall TR. I can time with a little help from my friends: effect of social enrichment on timing processes in Pigeons (Columba livia). Anim Cogn 2016; 19:1205-1213. [PMID: 27632157 DOI: 10.1007/s10071-016-1032-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 08/05/2016] [Accepted: 08/28/2016] [Indexed: 12/14/2022]
Abstract
There is evidence that impulsive decision-making is associated with errors in timing. However, there has been little attempt to identify the putative mechanism responsible for impulsive animals' timing errors. One means of manipulating impulsivity in non-human animals is providing different levels of access to conspecifics. These preclinical models have revealed that social isolation increases impulsive responding across a wide range of tasks. The goal of the present study was to determine whether social isolation modulates time perception in pigeons by inducing more variability or a bias to underestimate the passage of time in temporal judgments. A temporal bisection task was used to characterize time perception. One group of pigeons performed the bisection following social enrichment, and the remaining half of the pigeons were tested following social isolation. Results revealed pigeons in the social isolation condition categorized a temporal stimulus sample as "long" at shorter durations than pigeons in the social enrichment condition. These data highlight the mechanism(s) thought to underlie timing-based interventions aimed at reducing impulsivity in humans. Future work should consider whether impulsivity is produced by misperceptions of time or a reduced threshold for a response.
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Affiliation(s)
- Jennifer R Laude
- Department of Psychology, Stanford University, Stanford, CA, USA.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Carter W Daniels
- Department of Psychology, Arizona State University, Tempe, AZ, USA
| | - Jordan C Wade
- Department of Psychology, University of Kentucky, Lexington, KY, 40506-0044, USA
| | - Thomas R Zentall
- Department of Psychology, University of Kentucky, Lexington, KY, 40506-0044, USA.
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Strickland JC, Feinstein MA, Lacy RT, Smith MA. The effects of physical activity on impulsive choice: Influence of sensitivity to reinforcement amount and delay. Behav Processes 2016; 126:36-45. [PMID: 26964905 DOI: 10.1016/j.beproc.2016.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/03/2016] [Accepted: 03/05/2016] [Indexed: 11/30/2022]
Abstract
Impulsive choice is a diagnostic feature and/or complicating factor for several psychological disorders and may be examined in the laboratory using delay-discounting procedures. Recent investigators have proposed using quantitative measures of analysis to examine the behavioral processes contributing to impulsive choice. The purpose of this study was to examine the effects of physical activity (i.e., wheel running) on impulsive choice in a single-response, discrete-trial procedure using two quantitative methods of analysis. To this end, rats were assigned to physical activity or sedentary groups and trained to respond in a delay-discounting procedure. In this procedure, one lever always produced one food pellet immediately, whereas a second lever produced three food pellets after a 0, 10, 20, 40, or 80-s delay. Estimates of sensitivity to reinforcement amount and sensitivity to reinforcement delay were determined using (1) a simple linear analysis and (2) an analysis of logarithmically transformed response ratios. Both analyses revealed that physical activity decreased sensitivity to reinforcement amount and sensitivity to reinforcement delay. These findings indicate that (1) physical activity has significant but functionally opposing effects on the behavioral processes that contribute to impulsive choice and (2) both quantitative methods of analysis are appropriate for use in single-response, discrete-trial procedures.
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Affiliation(s)
- Justin C Strickland
- Department of Psychology, Box 7037, Davidson College, Davidson, NC 28035-7037, United States, United States
| | - Max A Feinstein
- Department of Psychology, Box 7037, Davidson College, Davidson, NC 28035-7037, United States, United States
| | - Ryan T Lacy
- Department of Psychology, Box 7037, Davidson College, Davidson, NC 28035-7037, United States, United States
| | - Mark A Smith
- Department of Psychology, Box 7037, Davidson College, Davidson, NC 28035-7037, United States, United States.
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Makowska IJ, Weary DM. Differences in Anticipatory Behaviour between Rats (Rattus norvegicus) Housed in Standard versus Semi-Naturalistic Laboratory Environments. PLoS One 2016; 11:e0147595. [PMID: 26820978 PMCID: PMC4731070 DOI: 10.1371/journal.pone.0147595] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/06/2016] [Indexed: 02/01/2023] Open
Abstract
Laboratory rats are usually kept in relatively small cages, but research has shown that they prefer larger and more complex environments. The physiological, neurological and health effects of standard laboratory housing are well established, but fewer studies have addressed the sustained emotional impact of a standard cage environment. One method of assessing affective states in animals is to look at the animals' anticipatory behaviour between the presentation of a cue signalling the arrival of a reward and the arrival of that reward. The primary aim of this study was to use anticipatory behaviour to assess the affective state experienced by female rats a) reared and housed long-term in a standard laboratory cage versus a semi-naturalistic environment, and b) before and after treatment with an antidepressant or an anxiolytic. A secondary aim was to add to the literature on anticipatory behaviour by describing and comparing the frequency and duration of individual elements of anticipatory behaviour displayed by rats reared in these two systems. In all experiments, total behavioural frequency was higher in standard-housed rats compared to rats from the semi-naturalistic condition, suggesting that standard-housed rats were more sensitive to rewards and experiencing poorer welfare than rats reared in the semi-naturalistic environment. What rats did in anticipation of the reward also differed between housing treatments, with standard-housed rats mostly rearing and rats from the semi-naturalistic condition mostly sitting facing the direction of the upcoming treat. Drug interventions had no effect on the quantity or form of anticipatory behaviour, suggesting that the poorer welfare experienced by standard-housed rats was not analogous to depression or anxiety, or alternatively that the drug interventions were ineffective. This study adds to mounting evidence that standard laboratory housing for rats compromises rat welfare, and provides further scientific support for recommendations that current minimum standards be raised.
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Affiliation(s)
- I. Joanna Makowska
- Animal Welfare Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel M. Weary
- Animal Welfare Program, University of British Columbia, Vancouver, British Columbia, Canada
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Marshall AT, Kirkpatrick K. Mechanisms of impulsive choice: III. The role of reward processes. Behav Processes 2015; 123:134-48. [PMID: 26506254 DOI: 10.1016/j.beproc.2015.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 02/07/2023]
Abstract
Two experiments examined the relationship between reward processing and impulsive choice. In Experiment 1, rats chose between a smaller-sooner (SS) reward (1 pellet, 10 s) and a larger-later (LL) reward (1, 2, and 4 pellets, 30 s). The rats then experienced concurrent variable-interval 30-s schedules with variations in reward magnitude to evaluate reward magnitude discrimination. LL choice behavior positively correlated with reward magnitude discrimination. In Experiment 2, rats chose between an SS reward (1 pellet, 10 s) and an LL reward (2 and 4 pellets, 30 s). The rats then received either a reward intervention which consisted of concurrent fixed-ratio schedules associated with different magnitudes to improve their reward magnitude discrimination, or a control task. All rats then experienced a post-intervention impulsive choice task followed by a reward magnitude discrimination task to assess intervention efficacy. The rats that received the intervention exhibited increases in post-intervention LL choice behavior, and made more responses for larger-reward magnitudes in the reward magnitude discrimination task, suggesting that the intervention heightened sensitivities to reward magnitude. The results suggest that reward magnitude discrimination plays a key role in individual differences in impulsive choice, and could be a potential target for further intervention developments.
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Arndt DL, Johns KC, Dietz ZK, Cain ME. Environmental condition alters amphetamine self-administration: role of the MGluR₅ receptor and schedule of reinforcement. Psychopharmacology (Berl) 2015; 232. [PMID: 26211759 PMCID: PMC4667709 DOI: 10.1007/s00213-015-4031-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE Evidence suggests that differential rearing influences the function of a receptor subtype critical for maintaining glutamate homeostasis. Maintaining homeostatic glutamatergic function may be an important protector against drug abuse. OBJECTIVE This study sought to determine if differential rearing influences the function of a receptor critical for glutamate homeostasis, which could in turn affect rates of amphetamine self-administration. METHODS Rats were assigned to enriched (EC), isolated (IC), or standard (SC) conditions. After rearing for 30 days, rats were trained to lever press for sucrose reinforcement before the implantation of indwelling jugular catheters. After reaching stable responding for amphetamine (0.03 or 0.1 mg/kg/infusion), rats were injected with five doses (0, 0.3, 1.0, 3.0, and 5.0 mg/kg) of the mGluR5 antagonist, 3-((2-methyl-1,3-thiazol-4-yl)ethynyl) pyridine hydrochloride (MTEP), 30 min before self-administration sessions. Following fixed-ratio (FR-1) testing, rats were administered identical doses of MTEP on a progressive-ratio (PR) reinforcement schedule. RESULTS MTEP (3.0 mg/kg) attenuated FR-1 self-administration (0.03 mg/kg/infusion) in IC rats. MTEP also dose-dependently attenuated amphetamine self-administration (0.1 mg/kg/infusion) during FR-1 and PR sessions, with 5.0 mg/kg MTEP attenuating amphetamine self-administration in IC and SC rats and 3.0 mg/kg MTEP attenuating amphetamine self-administration in EC and SC rats. PR results also revealed that IC rats not treated with MTEP were more motivated to self-administer the higher dose of amphetamine. CONCLUSIONS These results suggest that the mGlu5 receptor mediates differences in drug-taking behavior among differentially reared rats. Isolation also decreased sensitivity to MTEP, suggesting that environmental factors alter glutamate homeostasis which subsequently affects sensitivity and motivation to self-administer amphetamine.
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Affiliation(s)
- D L Arndt
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, Manhattan, KS, 66506, USA,
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Kirkpatrick K, Marshall AT, Smith AP. Mechanisms of Individual Differences in Impulsive and Risky Choice in Rats. COMPARATIVE COGNITION & BEHAVIOR REVIEWS 2015; 10:45-72. [PMID: 27695580 PMCID: PMC5045043 DOI: 10.3819/ccbr.2015.100003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Individual differences in impulsive and risky choice are key risk factors for a variety of maladaptive behaviors such as drug abuse, gambling, and obesity. In our rat model, ordered individual differences are stable across choice parameters, months of testing, and span a broad spectrum, suggesting that rats, like humans, exhibit trait-level impulsive and risky choice behaviors. In addition, impulsive and risky choices are highly correlated, suggesting a degree of correlation between these two traits. An examination of the underlying cognitive mechanisms has suggested an important role for timing processes in impulsive choice. In addition, in an examination of genetic factors in impulsive choice, the Lewis rat strain emerged as a possible animal model for studying disordered impulsive choice, with this strain demonstrating deficient delay processing. Early rearing environment also affected impulsive behaviors, with rearing in an enriched environment promoting adaptable and more self-controlled choices. The combined results with impulsive choice suggest an important role for timing and reward sensitivity in moderating impulsive behaviors. Relative reward valuation also affects risky choice, with manipulation of objective reward value (relative to an alternative reference point) resulting in loss chasing behaviors that predicted overall risky choice behaviors. The combined results are discussed in relation to domain-specific versus domain-general subjective reward valuation processes and the potential neural substrates of impulsive and risky choice.
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Young ME, McCoy AW. A delay discounting task produces a greater likelihood of waiting than a deferred gratification task. J Exp Anal Behav 2014; 103:180-95. [DOI: 10.1002/jeab.119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/07/2014] [Indexed: 11/09/2022]
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Marshall AT, Smith AP, Kirkpatrick K. Mechanisms of impulsive choice: I. Individual differences in interval timing and reward processing. J Exp Anal Behav 2014; 102:86-101. [PMID: 24965705 PMCID: PMC4232211 DOI: 10.1002/jeab.88] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/01/2014] [Indexed: 11/09/2022]
Abstract
Impulsive choice behavior incorporates the psychological mechanisms involved in the processing of the anticipated magnitude and delay until reward. The goal of the present experiment was to determine whether individual differences in such processes related to individual differences in impulsive choice behavior. Two groups of rats (Delay Group and Magnitude Group) were initially exposed to an impulsive choice task with choices between smaller-sooner (SS) and larger-later (LL) rewards. The Delay Group was subsequently exposed to a temporal discrimination task followed by a progressive interval task, whereas the Magnitude Group was exposed to a reward magnitude sensitivity task followed by a progressive ratio task. Intertask correlations revealed that the rats in the Delay Group that made more self-controlled (LL) choices also displayed lower standard deviations in the temporal bisection task and greater delay tolerance in the progressive interval task. Impulsive choice behavior in the Magnitude Group did not display any substantial correlations with the reward magnitude sensitivity and progressive ratio tasks. The results indicate the importance of core timing processes in impulsive choice behavior, and encourage further research examining the effects of changes in core timing processes on impulsive choice.
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Individual differences in impulsive and risky choice: effects of environmental rearing conditions. Behav Brain Res 2014; 269:115-27. [PMID: 24769268 DOI: 10.1016/j.bbr.2014.04.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/06/2014] [Accepted: 04/14/2014] [Indexed: 11/22/2022]
Abstract
The present experiment investigated early-rearing environment modulation of individual differences in impulsive and risky choice. Rats were reared in an isolated condition (IC; n=12), in which they lived alone without novel stimuli, or an enriched condition (EC; n=11), in which they lived among conspecifics with novel stimuli. The impulsive choice task involved choices between smaller-sooner (SS) versus larger-later (LL) rewards. The risky choice task involved choices between certain-smaller (C-S) versus uncertain-larger (U-L) rewards. Following choice testing, incentive motivation to work for food was measured using a progressive ratio task and correlated with choice behavior. HPLC analyses were conducted to determine how monoamine concentrations within the prefrontal cortex (PFC) and nucleus accumbens (NAC) related to behavior in different tasks. IC rats were more impulsive than EC rats, but they did not differ in risky choice behavior. However, choice behavior across tasks was significantly correlated (i.e., the more impulsive rats were also riskier). There were no group differences in monoamine levels, but noradrenergic and serotonergic concentrations were significantly correlated with impulsive and risky choice. Furthermore, serotonin and norepinephrine concentrations in the NAC significantly correlated with incentive motivation and the timing of the reward delays within the choice tasks. These results suggest a role for domain general processes in impulsive and risky choice and indicate the importance of the NAC and/or PFC in timing, reward processing, and choice behavior.
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