1
|
Panayi MC, Shetty S, Porod M, Bahena L, Xi ZX, Newman AH, Schoenbaum G. The selective D 3Receptor antagonist VK4-116 reverses loss of insight caused by self-administration of cocaine in rats. Neuropsychopharmacology 2024; 49:1590-1599. [PMID: 38582939 PMCID: PMC11319511 DOI: 10.1038/s41386-024-01858-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 04/01/2024] [Indexed: 04/08/2024]
Abstract
Chronic psychostimulant use causes long-lasting changes to neural and cognitive function that persist after long periods of abstinence. As cocaine users transition from drug use to abstinence, a parallel transition from hyperactivity to hypoactivity has been found in orbitofrontal-striatal glucose metabolism and striatal D2/D3-receptor activity. Targeting these changes pharmacologically, using highly selective dopamine D3-receptor (D3R) antagonists and partial agonists, has shown promise in reducing drug-taking, and attenuating relapse in animal models of cocaine and opioid use disorder. However, much less attention has been paid to treating the loss of insight, operationalized as the inability to infer likely outcomes, associated with chronic psychostimulant use. Here we tested the selective D3R antagonist VK4-116 as a treatment for this loss in rats with a prior history of cocaine use. Male and female rats were first trained to self-administer cocaine or a sucrose liquid for 2 weeks. After 4 weeks of abstinence, performance was assessed using a sensory preconditioning (SPC) learning paradigm. Rats were given VK4-116 (15 mg/kg, i.p.) or vehicle 30 min prior to each SPC training session, thus creating four drug-treatment groups: sucrose-vehicle, sucrose-VK4-116, cocaine-vehicle, cocaine-VK4-116. The control groups (sucrose-vehicle, sucrose-VK4-116) showed normal sensory preconditioning, whereas cocaine use (cocaine-vehicle) selectively disrupted responding to the preconditioned cue, an effect that was reversed in the cocaine-VK4-116 group, which demonstrating responding to the preconditioned cue at levels comparable to controls. These preclinical findings demonstrate that highly selective dopamine D3R antagonists, particularly VK4-116, can reverse the long-term negative behavioral consequences of cocaine use.
Collapse
Affiliation(s)
- Marios C Panayi
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA.
| | - Shohan Shetty
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Micaela Porod
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Lisette Bahena
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Zheng-Xiong Xi
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Amy Hauck Newman
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Geoffrey Schoenbaum
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD, 21224, USA.
| |
Collapse
|
2
|
Shi W, Li M, Zhang T, Yang C, Zhao D, Bai J. GABA system in the prefrontal cortex involved in psychostimulant addiction. Cereb Cortex 2024; 34:bhae319. [PMID: 39098820 DOI: 10.1093/cercor/bhae319] [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: 04/16/2024] [Revised: 07/08/2024] [Accepted: 07/17/2024] [Indexed: 08/06/2024] Open
Abstract
Drug addiction is a chronic and relapse brain disorder. Psychostimulants such as cocaine and amphetamine are highly addictive drugs. Abuse drugs target various brain areas in the nervous system. Recent studies have shown that the prefrontal cortex (PFC) plays a key role in regulating addictive behaviors. The PFC is made up of excitatory glutamatergic cells and gamma-aminobutyric acid (GABAergic) interneurons. Recently, studies showed that GABA level was related with psychostimulant addiction. In this review, we will introduce the role and mechanism of GABA and γ-aminobutyric acid receptors (GABARs) of the PFC in regulating drug addiction, especially in psychostimulant addiction.
Collapse
Affiliation(s)
- Wenjing Shi
- Faculty of Life Science and Technology, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| | - Minyu Li
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| | - Ting Zhang
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| | - Chunlong Yang
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| | - Dongdong Zhao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| | - Jie Bai
- Medical School, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, Yunnan, China
| |
Collapse
|
3
|
Barrett ST, Tracy ME, Bevins RA. Use of the overexpectation effect to reduce conditioned seeking behavior controlled by nicotine. Psychon Bull Rev 2024:10.3758/s13423-024-02524-1. [PMID: 38769272 DOI: 10.3758/s13423-024-02524-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 05/22/2024]
Abstract
Nicotine produces robust stimulus effects that can be conditioned to form associations with reinforcing nondrug stimuli. We examine how established associations to the nicotine stimulus may be weakened via the overexpectation effect. In two experiments, we separately conditioned sucrose associations to the interoceptive nicotine stimulus (0.4 mg/kg, SC) and to a "noisy" exteroceptive contextual stimulus (oscillating houselight and white noise) via the discriminated goal-tracking task. Thereafter, we presented additional sucrose pairings with the nicotine and noisy stimuli, now in compound. Testing of the conditioned goal-tracking evoked by the nicotine and noisy stimuli in isolation-before versus after compound conditioning (Experiment 1) or between treatment and control groups (Experiment 2)-demonstrated an attenuation of conditioned responding via the overexpectation effect. We suggest that applications of the overexpectation effect may provide some promise for treatments seeking to attenuate drug-evoked conditioned responses in situations where extinction-based interventions are not suitable.
Collapse
Affiliation(s)
- Scott T Barrett
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA.
| | - Matthew E Tracy
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Rick A Bevins
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| |
Collapse
|
4
|
Panayi MC, Shetty S, Porod M, Bahena L, Xi ZX, Newman AH, Schoenbaum G. The selective D3-Receptor antagonist VK4-116 effectively treats behavioral inflexibility in rats caused by self-administration and withdrawal from cocaine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.03.556083. [PMID: 37732238 PMCID: PMC10508727 DOI: 10.1101/2023.09.03.556083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Chronic psychostimulant use can cause long lasting changes to neural and cognitive function that persist even after long periods of abstinence. As cocaine users transition from drug use to abstinence, a parallel transition from hyperactivity to hypoactivity has been found in orbitofrontal-striatal glucose metabolism, and striatal D2/D3 receptor activity. Targeting these changes pharmacologically, using highly selective dopamine D3 receptor (D3R) antagonists and partial agonists, has shown significant promise in reducing drug-taking, and attenuating relapse in animal models of cocaine and opioid use disorder. However, much less attention has been focused on treating inflexible and potentially maladaptive non-drug behaviors following chronic psychostimulant use. Here we tested the selective D3R antagonist VK4-116 as a treatment for the long-term behavioral inflexibility in abstinent male and female rats with a prior history of chronic cocaine use. Rats were first trained to self-administer cocaine (0.75 mg/kg/reinforcer) or a sucrose liquid (10%, .04 mL/reinforcer) for 2 weeks (FR1 schedule, max 60 reinforcers in 3 hrs/ day), followed by 4 weeks of abstinence. Cognitive and behavioral flexibilities were then assessed using a sensory preconditioning (SPC) learning paradigm. Rats were given an VK4-116 (15 mg/kg, i.p.) or vehicle 30 mins prior to each SPC training session, thus creating four drug-treatment groups: sucrose-vehicle, sucrose-VK4-116, cocaine-vehicle, cocaine-VK4-116. The control groups (sucrose-vehicle, sucrose-VK4-116) demonstrated significant evidence of flexible SPC behavior, whereas cocaine use (cocaine-vehicle) disrupted SPC behavior. Remarkably, the D3R antagonist VK4-116 mitigated this cocaine deficit in the cocaine-VK4-116 group, demonstrating flexible SPC to levels comparable to the control groups. These preclinical findings demonstrate that highly selective dopamine D3R antagonists, particularly VK4-116, show significant promise as a pharmacological treatment for the long-term negative behavioral consequences of cocaine use disorder.
Collapse
Affiliation(s)
- Marios C Panayi
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Shohan Shetty
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Micaela Porod
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Lisette Bahena
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Zheng-Xiong Xi
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Amy Hauck Newman
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Geoffrey Schoenbaum
- National Institute on Drug Abuse Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| |
Collapse
|
5
|
Kahnt T. Computationally Informed Interventions for Targeting Compulsive Behaviors. Biol Psychiatry 2023; 93:729-738. [PMID: 36464521 PMCID: PMC9989040 DOI: 10.1016/j.biopsych.2022.08.028] [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: 05/12/2022] [Revised: 08/04/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
Compulsive behaviors are central to addiction and obsessive-compulsive disorder and can be understood as a failure of adaptive decision making. Particularly, they can be conceptualized as an imbalance in behavioral control, such that behavior is guided predominantly by learned rather than inferred outcome expectations. Inference is a computational process required for adaptive behavior, and recent work across species has identified the neural circuitry that supports inference-based decision making. This includes the orbitofrontal cortex, which has long been implicated in disorders of compulsive behavior. Inspired by evidence that modulating orbitofrontal cortex activity can alter inference-based behaviors, here we discuss noninvasive approaches to target these circuits in humans. Specifically, we discuss the potential of network-targeted transcranial magnetic stimulation and real-time neurofeedback to modulate the neural underpinnings of inference. Both interventions leverage recent advances in our understanding of the neurocomputational mechanisms of inference-based behavior and may be used to complement current treatment approaches for behavioral disorders.
Collapse
Affiliation(s)
- Thorsten Kahnt
- National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland.
| |
Collapse
|
6
|
Single nucleus transcriptomic analysis of rat nucleus accumbens reveals cell type-specific patterns of gene expression associated with volitional morphine intake. Transl Psychiatry 2022; 12:374. [PMID: 36075888 PMCID: PMC9458645 DOI: 10.1038/s41398-022-02135-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/09/2022] Open
Abstract
Opioid exposure is known to cause transcriptomic changes in the nucleus accumbens (NAc). However, no studies to date have investigated cell type-specific transcriptomic changes associated with volitional opioid taking. Here, we use single nucleus RNA sequencing (snRNAseq) to comprehensively characterize cell type-specific alterations of the NAc transcriptome in rats self-administering morphine. One cohort of male Brown Norway rats was injected with acute morphine (10 mg/kg, i.p.) or saline. A second cohort of rats was allowed to self-administer intravenous morphine (1.0 mg/kg/infusion) for 10 consecutive days. Each morphine-experienced rat was paired with a yoked saline control rat. snRNAseq libraries were generated from NAc punches and used to identify cell type-specific gene expression changes associated with volitional morphine taking. We identified 1106 differentially expressed genes (DEGs) in the acute morphine group, compared to 2453 DEGs in the morphine self-administration group, across 27 distinct cell clusters. Importantly, we identified 1329 DEGs that were specific to morphine self-administration. DEGs were identified in novel clusters of astrocytes, oligodendrocytes, and D1R- and D2R-expressing medium spiny neurons in the NAc. Cell type-specific DEGs included Rgs9, Celf5, Oprm1, and Pde10a. Upregulation of Rgs9 and Celf5 in D2R-expressing neurons was validated by RNAscope. Approximately 85% of all oligodendrocyte DEGs, nearly all of which were associated with morphine taking, were identified in two subtypes. Bioinformatic analyses identified cell type-specific upstream regulatory mechanisms of the observed transcriptome alterations and downstream signaling pathways, including both novel and previously identified molecular pathways. These findings show that volitional morphine taking is associated with distinct cell type-specific transcriptomic changes in the rat NAc and highlight specific striatal cell populations and novel molecular substrates that could be targeted to reduce compulsive opioid taking.
Collapse
|
7
|
Agency rescues competition for credit assignment among predictive cues from adverse learning conditions. Sci Rep 2021; 11:16187. [PMID: 34376741 PMCID: PMC8355250 DOI: 10.1038/s41598-021-95541-2] [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: 03/05/2021] [Accepted: 07/12/2021] [Indexed: 11/29/2022] Open
Abstract
A fundamental assumption of learning theories is that the credit assigned to predictive cues is not simply determined by their probability of reinforcement, but by their ability to compete with other cues present during learning. This assumption has guided behavioral and neural science research for decades, and tremendous empirical and theoretical advances have been made identifying the mechanisms of cue competition. However, when learning conditions are not optimal (e.g., when training is massed), cue competition is attenuated. This failure of the learning system exposes the individual’s vulnerability to form spurious associations in the real world. Here, we uncover that cue competition in rats can be rescued when conditions are suboptimal provided that the individual has agency over the learning experience. Our findings reveal a new effect of agency over learning on credit assignment among predictive cues, and open new avenues of investigation into the underlying mechanisms.
Collapse
|
8
|
Kahnt T, Schoenbaum G. Cross-species studies on orbitofrontal control of inference-based behavior. Behav Neurosci 2021; 135:109-119. [PMID: 34060869 PMCID: PMC9338401 DOI: 10.1037/bne0000401] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Many decisions are guided by expectations about their outcomes. These expectations can arise from two fundamentally different sources: from direct experience with outcomes and the events and actions that precede them or from mental simulations and inferences when direct experience is missing. Here we discuss four elegant tasks from animal learning theory (devaluation, sensory preconditioning, Pavlovian-to-instrumental transfer, and Pavlovian overexpectation) and how they can be used to isolate behavior that is based on such mental simulations from behavior that can be based solely on experience. We then review findings from studies in rodents, nonhuman primates, and humans that use these tasks in combination with neural recording and loss-of-function experiments to understand the role of the orbitofrontal cortex (OFC) in outcome inference. The results of these studies show that activity in the OFC is correlated with inferred outcome expectations and that an intact OFC is necessary for inference-based behavior and learning. In summary, these findings provide converging cross-species support for the idea that the OFC is critical for behavior that is based on inferred outcomes, whereas it is not required when expectations can be based on direct experience alone. This conclusion may have important implications for our understanding of the role of OFC in psychiatric disorders and how we may be able to treat them. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
Collapse
|
9
|
Abstract
Addiction is a disease characterized by compulsive drug seeking and consumption observed in 20-30% of users. An addicted individual will favor drug reward over natural rewards, despite major negative consequences. Mechanistic research on rodents modeling core components of the disease has identified altered synaptic transmission as the functional substrate of pathological behavior. While the initial version of a circuit model for addiction focused on early drug adaptive behaviors observed in all individuals, it fell short of accounting for the stochastic nature of the transition to compulsion. The model builds on the initial pharmacological effect common to all addictive drugs-an increase in dopamine levels in the mesolimbic system. Here, we consolidate this early model by integrating circuits underlying compulsion and negative reinforcement. We discuss the genetic and epigenetic correlates of individual vulnerability. Many recent data converge on a gain-of-function explanation for circuit remodeling, revealing blueprints for novel addiction therapies.
Collapse
Affiliation(s)
- Christian Lüscher
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland; .,Clinic of Neurology, Department of Clinical Neurosciences, Geneva University Hospital, CH-1211 Geneva, Switzerland
| | - Patricia H Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, Maryland 21218, USA.,The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| |
Collapse
|
10
|
Kimbrough A, Kononoff J, Simpson S, Kallupi M, Sedighim S, Palomino K, Conlisk D, Momper JD, de Guglielmo G, George O. Oxycodone self-administration and withdrawal behaviors in male and female Wistar rats. Psychopharmacology (Berl) 2020; 237:1545-1555. [PMID: 32114633 PMCID: PMC7269712 DOI: 10.1007/s00213-020-05479-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 02/06/2020] [Indexed: 12/22/2022]
Abstract
RATIONALE Over the last decade, oxycodone has become one of the most widely abused drugs in the USA. Oxycodone use disorder (OUD) is a serious health problem that has prompted a need to develop animal models of OUD that have both face and predictive validity. Oxycodone use in humans is more prevalent in women and leads to pronounced hyperalgesia and irritability during withdrawal. However, unclear is whether current animal models of oxycodone self-administration recapitulate these characteristics in humans. OBJECTIVES We assessed the face validity of a model of extended-access oxycodone self-administration in rats by examining the escalation of oxycodone intake and behavioral symptoms of withdrawal, including irritability-like behavior and mechanical nociception, in male and female Wistar rats. RESULTS Both male and female rats escalated their oxycodone intake over fourteen 12-h self-administration sessions. After escalation, female rats administered more drug than male rats. No differences in plasma oxycodone levels were identified, but males had a significantly higher level of oxycodone in the brain at 30 min. Extended access to oxycodone significantly decreased aggressive-like behavior and increased defensive-like behaviors when tested immediately after a 12-h self-administration session, followed by a rebound increase in aggressive-like behavior 12 h into withdrawal. Tests of mechanical nociception thresholds during withdrawal indicated pronounced hyperalgesia. No sex differences in irritability-like behavior or pain sensitivity were observed. CONCLUSIONS The present study demonstrated the face validity of the extended access model of oxycodone self-administration by identifying sex differences in the escalation of oxycodone intake and pronounced changes in pain and affective states.
Collapse
Affiliation(s)
- Adam Kimbrough
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA 92093-0737, USA
| | - Jenni Kononoff
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sierra Simpson
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA 92093-0737, USA,Department of Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Marsida Kallupi
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA 92093-0737, USA
| | - Sharona Sedighim
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA 92093-0737, USA
| | - Kenia Palomino
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Dana Conlisk
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jeremiah D. Momper
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Giordano de Guglielmo
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA 92093-0737, USA
| | - Olivier George
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA, 92093-0737, USA.
| |
Collapse
|
11
|
Role of Projections between Piriform Cortex and Orbitofrontal Cortex in Relapse to Fentanyl Seeking after Palatable Food Choice-Induced Voluntary Abstinence. J Neurosci 2020; 40:2485-2497. [PMID: 32051327 DOI: 10.1523/jneurosci.2693-19.2020] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 12/26/2019] [Accepted: 01/31/2020] [Indexed: 01/19/2023] Open
Abstract
We recently developed a rat model of relapse to drug seeking after food choice-induced voluntary abstinence. Here, we used this model to study the role of the orbitofrontal cortex (OFC) and its afferent projections in relapse to fentanyl seeking. We trained male and female rats to self-administer palatable food pellets for 6 d (6 h/d) and intravenous fentanyl (2.5 μg/kg/infusion) for 12 d (6 h/d). We assessed relapse to fentanyl seeking after 13-14 voluntary abstinence days, achieved through a discrete choice procedure between fentanyl infusions and palatable food (20 trials/d). In both sexes, relapse after food choice-induced abstinence was associated with increased expression of the activity marker Fos in the OFC. Pharmacological inactivation of the OFC with muscimol plus baclofen (50 + 50 ng/side) decreased relapse to fentanyl seeking. We then determined projection-specific activation of OFC afferents during the relapse test by using Fos plus the retrograde tracer cholera toxin B (injected into the OFC). Relapse to fentanyl seeking was associated with increased Fos expression in the piriform cortex (Pir) neurons projecting to the OFC, but not in projections from the basolateral amygdala and thalamus. Pharmacological inactivation of the Pir with muscimol plus baclofen decreased relapse to fentanyl seeking after voluntary abstinence. Next, we used an anatomical disconnection procedure to determine whether projections between the Pir and OFC are critical for relapse to fentanyl seeking. Unilateral muscimol plus baclofen injections into the Pir in one hemisphere plus unilateral muscimol plus baclofen injections into the OFC in the contralateral, but not ipsilateral, hemisphere decreased relapse. Our results identify Pir-OFC projections as a new motivation-related pathway critical to relapse to opioid seeking after voluntary abstinence.SIGNIFICANCE STATEMENT There are few preclinical studies of fentanyl relapse, and these studies have used experimenter-imposed extinction or forced abstinence procedures. In humans, however, abstinence is often voluntary, with drug available in the drug environment but forgone in favor of nondrug alternative reinforcers. We recently developed a rat model of drug relapse after palatable food choice-induced voluntary abstinence. Here, we used classical pharmacology, immunohistochemistry, and retrograde tracing to demonstrate a critical role of the piriform and orbitofrontal cortices in relapse to opioid seeking after voluntary abstinence.
Collapse
|
12
|
Kuhn BN, Kalivas PW, Bobadilla AC. Understanding Addiction Using Animal Models. Front Behav Neurosci 2019; 13:262. [PMID: 31849622 PMCID: PMC6895146 DOI: 10.3389/fnbeh.2019.00262] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022] Open
Abstract
Drug addiction is a neuropsychiatric disorder with grave personal consequences that has an extraordinary global economic impact. Despite decades of research, the options available to treat addiction are often ineffective because our rudimentary understanding of drug-induced pathology in brain circuits and synaptic physiology inhibits the rational design of successful therapies. This understanding will arise first from animal models of addiction where experimentation at the level of circuits and molecular biology is possible. We will review the most common preclinical models of addictive behavior and discuss the advantages and disadvantages of each. This includes non-contingent models in which animals are passively exposed to rewarding substances, as well as widely used contingent models such as drug self-administration and relapse. For the latter, we elaborate on the different ways of mimicking craving and relapse, which include using acute stress, drug administration or exposure to cues and contexts previously paired with drug self-administration. We further describe paradigms where drug-taking is challenged by alternative rewards, such as appetitive foods or social interaction. In an attempt to better model the individual vulnerability to drug abuse that characterizes human addiction, the field has also established preclinical paradigms in which drug-induced behaviors are ranked by various criteria of drug use in the presence of negative consequences. Separation of more vulnerable animals according to these criteria, along with other innate predispositions including goal- or sign-tracking, sensation-seeking behavior or impulsivity, has established individual genetic susceptibilities to developing drug addiction and relapse vulnerability. We further examine current models of behavioral addictions such as gambling, a disorder included in the DSM-5, and exercise, mentioned in the DSM-5 but not included yet due to insufficient peer-reviewed evidence. Finally, after reviewing the face validity of the aforementioned models, we consider the most common standardized tests used by pharmaceutical companies to assess the addictive potential of a drug during clinical trials.
Collapse
Affiliation(s)
| | - Peter W. Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Ana-Clara Bobadilla
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| |
Collapse
|
13
|
Takahashi YK, Stalnaker TA, Marrero-Garcia Y, Rada RM, Schoenbaum G. Expectancy-Related Changes in Dopaminergic Error Signals Are Impaired by Cocaine Self-Administration. Neuron 2019; 101:294-306.e3. [PMID: 30653935 DOI: 10.1016/j.neuron.2018.11.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/30/2018] [Accepted: 11/13/2018] [Indexed: 11/29/2022]
Abstract
Addiction is a disorder of behavioral control and learning. While this may reflect pre-existing propensities, drug use also clearly contributes by causing changes in outcome processing in prefrontal and striatal regions. This altered processing is associated with behavioral deficits, including changes in learning. These areas provide critical input to midbrain dopamine neurons regarding expected outcomes, suggesting that effects on learning may result from changes in dopaminergic error signaling. Here, we show that dopamine neurons recorded in rats that had self-administered cocaine failed to suppress firing on omission of an expected reward and exhibited lower amplitude and imprecisely timed increases in firing to an unexpected reward. Learning also appeared to have less of an effect on reward-evoked and cue-evoked firing in the cocaine-experienced rats. Overall, the changes are consistent with reduced fidelity of input regarding the expected outcomes, such as their size, timing, and overall value, because of cocaine use.
Collapse
Affiliation(s)
- Yuji K Takahashi
- Intramural Research program of the National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA.
| | - Thomas A Stalnaker
- Intramural Research program of the National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | - Yasmin Marrero-Garcia
- Intramural Research program of the National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | - Ray M Rada
- Intramural Research program of the National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | - Geoffrey Schoenbaum
- Intramural Research program of the National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
14
|
Lim TV, Cardinal RN, Savulich G, Jones PS, Moustafa AA, Robbins TW, Ersche KD. Impairments in reinforcement learning do not explain enhanced habit formation in cocaine use disorder. Psychopharmacology (Berl) 2019; 236:2359-2371. [PMID: 31372665 PMCID: PMC6695345 DOI: 10.1007/s00213-019-05330-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/08/2019] [Indexed: 12/21/2022]
Abstract
RATIONALE Drug addiction has been suggested to develop through drug-induced changes in learning and memory processes. Whilst the initiation of drug use is typically goal-directed and hedonically motivated, over time, drug-taking may develop into a stimulus-driven habit, characterised by persistent use of the drug irrespective of the consequences. Converging lines of evidence suggest that stimulant drugs facilitate the transition of goal-directed into habitual drug-taking, but their contribution to goal-directed learning is less clear. Computational modelling may provide an elegant means for elucidating changes during instrumental learning that may explain enhanced habit formation. OBJECTIVES We used formal reinforcement learning algorithms to deconstruct the process of appetitive instrumental learning and to explore potential associations between goal-directed and habitual actions in patients with cocaine use disorder (CUD). METHODS We re-analysed appetitive instrumental learning data in 55 healthy control volunteers and 70 CUD patients by applying a reinforcement learning model within a hierarchical Bayesian framework. We used a regression model to determine the influence of learning parameters and variations in brain structure on subsequent habit formation. RESULTS Poor instrumental learning performance in CUD patients was largely determined by difficulties with learning from feedback, as reflected by a significantly reduced learning rate. Subsequent formation of habitual response patterns was partly explained by group status and individual variation in reinforcement sensitivity. White matter integrity within goal-directed networks was only associated with performance parameters in controls but not in CUD patients. CONCLUSIONS Our data indicate that impairments in reinforcement learning are insufficient to account for enhanced habitual responding in CUD.
Collapse
Affiliation(s)
- T V Lim
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK
| | - R N Cardinal
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK
- Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK
- Liaison Psychiatry Service, Cambridgeshire & Peterborough NHS Foundation Trust, Box 190, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK
| | - G Savulich
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK
- Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK
| | - P S Jones
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK
| | - A A Moustafa
- School of Social Sciences and Psychology, MARCS Institute for Brain and Behaviour, Western Sydney University, Sydney, NSW, Australia
| | - T W Robbins
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK
- Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK
| | - K D Ersche
- Departments of Psychiatry, Psychology and Clinical Neurosciences, University of Cambridge, Herchel Smith Building for Brain & Mind Sciences, Cambridge Biomedical Campus, Cambridge, CB2 0SZ, UK.
- Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK.
| |
Collapse
|
15
|
Guo H, Xie Q, Cui J, Xu D, Deji C, Chen Y, Wang Y, Lai J. Naloxone reversed cognitive impairments induced by repeated morphine under heavy perceptual load in the 5-choice serial reaction time task. J Neurosci Res 2019; 97:1051-1065. [PMID: 31081159 DOI: 10.1002/jnr.24427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 02/28/2019] [Accepted: 03/18/2019] [Indexed: 12/23/2022]
Abstract
Repeated opioids abuse may produce long-lasting and complicated cognitive deficits in individuals. Naloxone is a typical mu-opioid receptor antagonist widely used in clinical treatment for opioid overdose and opioid abuse. However, it remains unclear whether naloxone affects morphine-induced cognitive deficits. Using the 5-choice serial reaction time task (5-CSRTT), the present study investigated cognitive profiles including attention, impulsivity, compulsivity, and processing speed in repeated morphine-treated mice. Repeated morphine administration (10 mg/kg, i.p.) induced complex cognitive changes including decreased attention and increased impulsivity, compulsivity, processing speed. Systemic naloxone administration (5 mg/kg, i.p.) reversed these cognitive changes under the heavy perceptual load in 5-CSRTT. Using the novel object recognition (NOR), Y-maze and open-field test (OFT), the present study investigated the memory ability and locomotor activity. Naloxone reversed the effect of morphine on recognition memory and locomotion but had no effect on working memory. In addition, repeated morphine administration decreased the expression of postsynaptic density protein 95 (PSD95) and cAMP response element binding protein (CREB) phosphorylation in the prefrontal cortex (PFC) and hippocampus (HIP), and these effects were significantly reversed by naloxone in PFC. Our study suggests that repeated exposure to morphine affects multiple cognitive aspects and impairs synaptic functions. Systemic naloxone treatment reverses the mu-opioids-induced cognitive changes, especially under the heavy perceptual load, possibly by restoring the synaptic dysfunctions.
Collapse
Affiliation(s)
- Hao Guo
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Qiaoli Xie
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Jingjing Cui
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Dan Xu
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Cuola Deji
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Yuanyuan Chen
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Yunpeng Wang
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Jianghua Lai
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China.,Key Laboratory of Ministry of Public Health for Forensic Science, Xi'an, China
| |
Collapse
|
16
|
Moorman DE. The role of the orbitofrontal cortex in alcohol use, abuse, and dependence. Prog Neuropsychopharmacol Biol Psychiatry 2018; 87:85-107. [PMID: 29355587 PMCID: PMC6072631 DOI: 10.1016/j.pnpbp.2018.01.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/22/2017] [Accepted: 01/13/2018] [Indexed: 12/21/2022]
Abstract
One of the major functions of the orbitofrontal cortex (OFC) is to promote flexible motivated behavior. It is no surprise, therefore, that recent work has demonstrated a prominent impact of chronic drug use on the OFC and a potential role for OFC disruption in drug abuse and addiction. Among drugs of abuse, the use of alcohol is particularly salient with respect to OFC function. Although a number of studies in humans have implicated OFC dysregulation in alcohol use disorders, animal models investigating the association between OFC and alcohol use are only beginning to be developed, and there is still a great deal to be revealed. The goal of this review is to consider what is currently known regarding the role of the OFC in alcohol use and dependence. I will first provide a brief, general overview of current views of OFC function and its contributions to drug seeking and addiction. I will then discuss research to date related to the OFC and alcohol use, both in human clinical populations and in non-human models. Finally I will consider issues and strategies to guide future study that may identify this brain region as a key player in the transition from moderated to problematic alcohol use and dependence.
Collapse
Affiliation(s)
- David E. Moorman
- Department of Psychological and Brain Sciences, Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst MA 01003 USA
| |
Collapse
|
17
|
Stochastic synaptic plasticity underlying compulsion in a model of addiction. Nature 2018; 564:366-371. [PMID: 30568192 DOI: 10.1038/s41586-018-0789-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 11/13/2018] [Indexed: 01/08/2023]
Abstract
Activation of the mesolimbic dopamine system reinforces goal-directed behaviours. With repetitive stimulation-for example, by chronic drug abuse-the reinforcement may become compulsive and intake continues even in the face of major negative consequences. Here we gave mice the opportunity to optogenetically self-stimulate dopaminergic neurons and observed that only a fraction of mice persevered if they had to endure an electric shock. Compulsive lever pressing was associated with an activity peak in the projection terminals from the orbitofrontal cortex (OFC) to the dorsal striatum. Although brief inhibition of OFC neurons temporarily relieved compulsive reinforcement, we found that transmission from the OFC to the striatum was permanently potentiated in persevering mice. To establish causality, we potentiated these synapses in vivo in mice that stopped optogenetic self-stimulation of dopamine neurons because of punishment; this led to compulsive lever pressing, whereas depotentiation in persevering mice had the converse effect. In summary, synaptic potentiation of transmission from the OFC to the dorsal striatum drives compulsive reinforcement, a defining symptom of addiction.
Collapse
|
18
|
Park TY, Nishida KS, Wilson CM, Jaiswal S, Scott J, Hoy AR, Selwyn RG, Dardzinski BJ, Choi KH. Effects of isoflurane anesthesia and intravenous morphine self-administration on regional glucose metabolism ([ 18 F]FDG-PET) of male Sprague-Dawley rats. Eur J Neurosci 2017; 45:922-931. [PMID: 28196306 DOI: 10.1111/ejn.13542] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 01/22/2023]
Abstract
Although certain drugs of abuse are known to disrupt brain glucose metabolism (BGluM), the effects of opiates on BGluM are not well characterized. Moreover, preclinical positron emission tomography (PET) studies anesthetize animals during the scan, which limits clinical applications. We investigated the effects of (i) isoflurane anesthesia and (ii) intravenous morphine self-administration (MSA) on BGluM in rats. Jugular vein cannulated adult male Sprague-Dawley rats self-administered either saline (SSA) or morphine (0.5 mg/kg/infusion, 4 h/day for 12 days). All animals were scanned twice with [18 F]-fluoro-deoxy-glucose (FDG)-PET/CT at a baseline and at 2-day withdrawal from self-administration. After the IV injection of FDG, one batch of animals (n = 14) was anesthetized with isoflurane and the other batch (n = 16) was kept awake during the FDG uptake (45 min). After FDG uptake, all animals were anesthetized in order to perform a PET/CT scan (30 min). Isoflurane anesthesia, as compared to the awake condition, reduced BGluM in the olfactory, cortex, thalamus, and basal ganglia, while increasing BGluM in the midbrain, hypothalamus, hippocampus, and cerebellum. Morphine self-administered animals exhibited withdrawal signs (piloerection and increased defecation), drug seeking, and locomotor stimulation to morphine (0.5 mg/kg) during the 2 day withdrawal. The BGluM in the striatum was increased in the MSA group as compared to the SSA group; this effect was observed only in the isoflurane anesthesia, not the awake condition. These findings suggest that the choice of the FDG uptake condition may be important in preclinical PET studies and increased BGluM in the striatum may be associated with opiate seeking in withdrawal.
Collapse
Affiliation(s)
- Thomas Y Park
- Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.,Center for the Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kevin S Nishida
- Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.,Center for the Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Colin M Wilson
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Department of Radiology, University of New Mexico, Albuquerque, NM, USA
| | - Shalini Jaiswal
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Jessica Scott
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Andrew R Hoy
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Reed G Selwyn
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Department of Radiology, University of New Mexico, Albuquerque, NM, USA.,Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Bernard J Dardzinski
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kwang H Choi
- Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.,Center for the Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| |
Collapse
|
19
|
Reward loss and addiction: Opportunities for cross-pollination. Pharmacol Biochem Behav 2017; 154:39-52. [DOI: 10.1016/j.pbb.2017.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 12/20/2022]
|
20
|
Abstract
This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
| |
Collapse
|
21
|
Schoenbaum G, Chang CY, Lucantonio F, Takahashi YK. Thinking Outside the Box: Orbitofrontal Cortex, Imagination, and How We Can Treat Addiction. Neuropsychopharmacology 2016; 41:2966-2976. [PMID: 27510424 PMCID: PMC5101562 DOI: 10.1038/npp.2016.147] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 12/23/2022]
Abstract
Addiction involves an inability to control drug-seeking behavior. While this may be thought of as secondary to an overwhelming desire for drugs, it could equally well reflect a failure of the brain mechanisms that allow addicts to learn about and mentally simulate non-drug consequences. Importantly, this process of mental simulation draws upon, but is not normally bound by, our past experiences. Rather we have the ability to think outside the box of our past, integrating knowledge gained from a variety of similar and not-so-similar life experiences to derive estimates or imagine what might happen next. These estimates influence our current behavior directly and also affect future behavior by serving as the background against which outcomes are evaluated to support learning. Here we will review evidence, from our own work using a Pavlovian over-expectation task as well as from other sources, that the orbitofrontal cortex is a critical node in the neural circuit that generates these estimates. Further we will offer the specific hypothesis that degradation of this function secondary to drug-induced changes is a critical and likely addressable part of addiction.
Collapse
Affiliation(s)
- Geoffrey Schoenbaum
- NIDA Intramural Research Program, Baltimore, MD, USA,NIDA Intramural Research Program, 251 Bayview Dr, Baltimore, MD 21224, USA, Tel: +1 443 722 6746, E-mail:
| | | | | | | |
Collapse
|
22
|
Sadacca BF, Wikenheiser AM, Schoenbaum G. Toward a theoretical role for tonic norepinephrine in the orbitofrontal cortex in facilitating flexible learning. Neuroscience 2016; 345:124-129. [PMID: 27102419 DOI: 10.1016/j.neuroscience.2016.04.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 04/08/2016] [Accepted: 04/11/2016] [Indexed: 10/21/2022]
Abstract
To adaptively respond in a complex, changing world, animals need to flexibly update their understanding of the world when their expectations are violated. Though several brain regions in rodents and primates have been implicated in aspects of this updating, current models of orbitofrontal cortex (OFC) and norepinephrine neurons of the locus coeruleus (LC-NE) suggest that each plays a role in responding to environmental change, where the OFC allows updating of prior learning to occur without overwriting or unlearning one's previous understanding of the world that changed, while elevated tonic NE allows for increased flexibility in behavior that tracks an animal's uncertainty. In light of recent studies highlighting a specific LC-NE projection to the OFC, in this review we discuss current models of OFC and NE function, and their potential synergy in the updating of associations following environmental change.
Collapse
Affiliation(s)
- Brian F Sadacca
- Intramural Research Program of the National Institute on Drug Abuse, NIH, United States.
| | - Andrew M Wikenheiser
- Intramural Research Program of the National Institute on Drug Abuse, NIH, United States
| | - Geoffrey Schoenbaum
- Intramural Research Program of the National Institute on Drug Abuse, NIH, United States; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, United States; Department of Neuroscience, Johns Hopkins School of Medicine, United States.
| |
Collapse
|
23
|
Kahnt T, Tobler PN. Dopamine regulates stimulus generalization in the human hippocampus. eLife 2016; 5:e12678. [PMID: 26830462 PMCID: PMC4755747 DOI: 10.7554/elife.12678] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/22/2015] [Indexed: 11/13/2022] Open
Abstract
The ability to generalize previously learned information to novel situations is fundamental for adaptive behavior. However, too wide or too narrow generalization is linked to neuropsychiatric disorders. Previous research suggests that interactions between the dopaminergic system and the hippocampus may play a role in generalization, but whether and how the degree of generalization can be modulated via these pathways is currently unknown. Here, we addressed this question in humans using pharmacology, functional magnetic resonance imaging, and computational modeling. Blocking dopamine D2-receptors (D2R) altered generalization behavior as revealed by an increased kurtosis of the generalization gradient, and a decreased width of model-derived generalization parameters. Moreover, D2R-blockade modulated similarity-based responses in the hippocampus and decreased midbrain-hippocampal connectivity, which in turn correlated with individual differences in generalization. These results suggest that dopaminergic activity in the hippocampus may relate to the degree of generalization and highlight a potential target for treatment.
Collapse
Affiliation(s)
- Thorsten Kahnt
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Philippe N Tobler
- Department of Economics, Laboratory for Social and Neural Systems Research, University of Zurich, Zürich, Switzerland
| |
Collapse
|