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Lee D, Lau N, Liu L, Root CM. Transformation of valence signaling in a striatopallidal circuit. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.01.551547. [PMID: 37577586 PMCID: PMC10418236 DOI: 10.1101/2023.08.01.551547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The ways in which sensory stimuli acquire motivational valence through association with other stimuli is one of the simplest forms of learning. Though we have identified many brain nuclei that play various roles in reward processing, a significant gap remains in understanding how valence encoding transforms through the layers of sensory processing. To address this gap, we carried out a comparative investigation of the anteromedial olfactory tubercle (OT), and the ventral pallidum (VP) - 2 connected nuclei of the basal ganglia which have both been implicated in reward processing. First, using anterograde and retrograde tracing, we show that both D1 and D2 neurons of the anteromedial OT project primarily to the VP and minimally elsewhere. Using 2-photon calcium imaging, we then investigated how the identity of the odor and reward contingency of the odor are differently encoded by neurons in either structure during a classical conditioning paradigm. We find that VP neurons robustly encode reward contingency, but not identity, in low-dimensional space. In contrast, the OT neurons primarily encode odor identity in high-dimensional space. Although D1 OT neurons showed larger responses to rewarded odors than other odors, consistent with prior findings, we interpret this as identity encoding with enhanced contrast. Finally, using a novel conditioning paradigm that decouples reward contingency and licking vigor, we show that both features are encoded by non-overlapping VP neurons. These results provide a novel framework for the striatopallidal circuit in which a high-dimensional encoding of stimulus identity is collapsed onto a low-dimensional encoding of motivational valence.
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2
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Yang L, Fang LZ, Lynch MR, Xu CS, Hahm H, Zhang Y, Heitmeier MR, Costa V, Samineni VK, Creed MC. Transcriptomic landscape of mammalian ventral pallidum at single-cell resolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595793. [PMID: 38826431 PMCID: PMC11142225 DOI: 10.1101/2024.05.24.595793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The ventral pallidum (VP) is critical for motivated behaviors. While contemporary work has begun to elucidate the functional diversity of VP neurons, the molecular heterogeneity underlying this functional diversity remains incompletely understood. We used snRNA-seq and in situ hybridization to define the transcriptional taxonomy of VP cell types in mice, macaques, and baboons. We found transcriptional conservation between all three species, within the broader neurochemical cell types. Unique dopaminoceptive and cholinergic subclusters were identified and conserved across both primate species but had no homolog in mice. This harmonized consensus VP cellular atlas will pave the way for understanding the structure and function of the VP and identified key neuropeptides, neurotransmitters, and neuro receptors that could be targeted within specific VP cell types for functional investigations.
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Faget L, Oriol L, Lee WC, Zell V, Sargent C, Flores A, Hollon NG, Ramanathan D, Hnasko TS. Ventral pallidum GABA and glutamate neurons drive approach and avoidance through distinct modulation of VTA cell types. Nat Commun 2024; 15:4233. [PMID: 38762463 PMCID: PMC11102457 DOI: 10.1038/s41467-024-48340-y] [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: 05/19/2023] [Accepted: 04/26/2024] [Indexed: 05/20/2024] Open
Abstract
The ventral pallidum (VP) contains GABA and glutamate neurons projecting to ventral tegmental area (VTA) whose stimulation drives approach and avoidance, respectively. Yet little is known about the mechanisms by which VP cell types shape VTA activity and drive behavior. Here, we found that both VP GABA and glutamate neurons were activated during approach to reward or by delivery of an aversive stimulus. Stimulation of VP GABA neurons inhibited VTA GABA, but activated dopamine and glutamate neurons. Remarkably, stimulation-evoked activation was behavior-contingent such that VTA recruitment was inhibited when evoked by the subject's own action. Conversely, VP glutamate neurons activated VTA GABA, as well as dopamine and glutamate neurons, despite driving aversion. However, VP glutamate neurons evoked dopamine in aversion-associated ventromedial nucleus accumbens (NAc), but reduced dopamine release in reward-associated dorsomedial NAc. These findings show how heterogeneous VP projections to VTA can be engaged to shape approach and avoidance behaviors.
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Affiliation(s)
- Lauren Faget
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
| | - Lucie Oriol
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Wen-Chun Lee
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Vivien Zell
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Cody Sargent
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Andrew Flores
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Nick G Hollon
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Dhakshin Ramanathan
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Thomas S Hnasko
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
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Kallupi M, Ciccocioppo R. Cue-induced reinstatement of seeking behavior in male rats is independent from the rewarding value of the primary reinforcer: Effect of mGluR5 blockade. Neuropharmacology 2023; 240:109694. [PMID: 37659439 PMCID: PMC11094430 DOI: 10.1016/j.neuropharm.2023.109694] [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: 07/02/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023]
Abstract
Environmental conditioning factors have a profound impact on alcohol-seeking behavior and the maintenance of alcohol use in individuals with alcohol dependence. Cues associated with alcohol, depending on the perceived value of the primary reinforcer, gain salience and can trigger relapse. This study investigates the correlation between the reward magnitude of the primary reinforcer and the reinstatement evoked by cues predictive of their availability in male rats. Rat self-administration procedures were used to test reinstatement, with reinforcers consisting of 10% alcohol, 10% sucrose, or 2% sodium chloride (NaCl) experienced under need-state conditions. The effect of MTEP ([(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine), a selective metabotropic glutamate receptor 5 (mGluR5) antagonist, on motivation and reinstatement behaviors was also evaluated. RESULTS: demonstrate that under Fixed Ratio 1 (FR1) schedule, the three reinforcers maintain operant responding with the following order of magnitude 10% sucrose >2% NaCl >10% alcohol > water. Under a progressive ratio (PR) schedule of reinforcement, rats exhibit a significantly higher breakpoint for 2% NaCl (under Na-depletion), followed by 10% sucrose and 10% alcohol. After extinction, a significant reinstatement is observed with the magnitude order of 10% sucrose >10% alcohol >2% NaCl. However, only re-exposure to alcohol-paired cues induced significant reinstatement of alcohol-seeking after 4 and 8 months. Treatment with MTEP significantly reduces reinstatement of responding across all reinforcers, with the strongest effect observed on alcohol-seeking. These findings suggest that mGluR5 plays a general role in controlling cue-reactivity, but the effect is prominent in the case of alcohol compared to natural rewards. In conclusion, the results demonstrate a remarkable dissociation between the rewarding magnitude of the primary reinforcer and its ability to trigger relapse upon presentation of a cue previously associated with it. Importantly, alcohol, despite having lower intrinsic motivational value compared to a natural reward (sucrose) or a consummatory stimulus experienced under need state conditions (NaCl), can elicit more robust and longer-term reinstatement of seeking responses. Finally, our data demonstrate a significant involvement of the mGluR5 system in the regulation of seeking behavior.
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Affiliation(s)
- Marsida Kallupi
- Department of Psychiatry, University of California, San Diego, USA.
| | - Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
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Berridge KC. Separating desire from prediction of outcome value. Trends Cogn Sci 2023; 27:932-946. [PMID: 37543439 PMCID: PMC10527990 DOI: 10.1016/j.tics.2023.07.007] [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: 05/17/2022] [Revised: 07/10/2023] [Accepted: 07/14/2023] [Indexed: 08/07/2023]
Abstract
Individuals typically want what they expect to like, often based on memories of previous positive experiences. However, in some situations desire can decouple completely from memories and from learned predictions of outcome value. The potential for desire to separate from prediction arises from independent operating rules that control motivational incentive salience. Incentive salience, or 'wanting', is a type of mesolimbic desire that evolved for adaptive goals, but can also generate maladaptive addictions. Two proof-of-principle examples are presented here to show how motivational 'wanting' can soar above memory-based predictions of outcome value: (i) 'wanting what is remembered to be disgusting', and (ii) 'wanting what is predicted to hurt'. Consequently, even outcomes remembered and predicted to be negatively aversive can become positively 'wanted'. Similarly, in human addictions, people may experience powerful cue-triggered cravings for outcomes that are not predicted to be enjoyable.
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Affiliation(s)
- Kent C Berridge
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.
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Faget L, Oriol L, Lee WC, Sargent C, Ramanathan D, Hnasko TS. Ventral pallidum GABA and glutamate neurons drive approach and avoidance through distinct modulation of VTA cell types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548750. [PMID: 37502884 PMCID: PMC10369949 DOI: 10.1101/2023.07.12.548750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The ventral pallidum (VP) contains GABA and glutamate (Glut) neurons projecting to ventral tegmental area (VTA) whose stimulation drives approach and avoidance, respectively. Yet little is known about the cell-type-specific mechanisms by which VP projections to VTA drive behavior. Here, we found that both VP GABA and Glut neurons were activated during approach to reward or delivery of an aversive stimulus. Stimulation of VP GABA neurons inhibited VTA GABA, but activated dopamine (DA) and glutamate neurons. Remarkably, this cell-type-specific recruitment was behavior-contingent such that VTA recruitment was inhibited when evoked by the subject's own action. Conversely, VP Glut neurons activated VTA GABA, as well as DA and Glut neurons, despite driving aversion. However, VP Glut neurons evoked DA in reward-associated ventromedial nucleus accumbens (NAc), but reduced DA in aversion-associated dorsomedial NAc. These findings show how heterogeneous VP cell types can engage VTA cell types to shape approach and avoidance behaviors.
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Affiliation(s)
- Lauren Faget
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Lucie Oriol
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Wen-Chun Lee
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Cody Sargent
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Dhakshin Ramanathan
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Thomas S. Hnasko
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
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7
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Soares-Cunha C, Heinsbroek JA. Ventral pallidal regulation of motivated behaviors and reinforcement. Front Neural Circuits 2023; 17:1086053. [PMID: 36817646 PMCID: PMC9932340 DOI: 10.3389/fncir.2023.1086053] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/06/2023] [Indexed: 02/05/2023] Open
Abstract
The interconnected nuclei of the ventral basal ganglia have long been identified as key regulators of motivated behavior, and dysfunction of this circuit is strongly implicated in mood and substance use disorders. The ventral pallidum (VP) is a central node of the ventral basal ganglia, and recent studies have revealed complex VP cellular heterogeneity and cell- and circuit-specific regulation of reward, aversion, motivation, and drug-seeking behaviors. Although the VP is canonically considered a relay and output structure for this circuit, emerging data indicate that the VP is a central hub in an extensive network for reward processing and the regulation of motivation that extends beyond classically defined basal ganglia borders. VP neurons respond temporally faster and show more advanced reward coding and prediction error processing than neurons in the upstream nucleus accumbens, and regulate the activity of the ventral mesencephalon dopamine system. This review will summarize recent findings in the literature and provide an update on the complex cellular heterogeneity and cell- and circuit-specific regulation of motivated behaviors and reinforcement by the VP with a specific focus on mood and substance use disorders. In addition, we will discuss mechanisms by which stress and drug exposure alter the functioning of the VP and produce susceptibility to neuropsychiatric disorders. Lastly, we will outline unanswered questions and identify future directions for studies necessary to further clarify the central role of VP neurons in the regulation of motivated behaviors. Significance: Research in the last decade has revealed a complex cell- and circuit-specific role for the VP in reward processing and the regulation of motivated behaviors. Novel insights obtained using cell- and circuit-specific interrogation strategies have led to a major shift in our understanding of this region. Here, we provide a comprehensive review of the VP in which we integrate novel findings with the existing literature and highlight the emerging role of the VP as a linchpin of the neural systems that regulate motivation, reward, and aversion. In addition, we discuss the dysfunction of the VP in animal models of neuropsychiatric disorders.
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Affiliation(s)
- Carina Soares-Cunha
- 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
| | - Jasper A. Heinsbroek
- Department of Anesthesiology, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States
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Uchida Y, Hikida T, Yamashita Y. Computational Mechanisms of Osmoregulation: A Reinforcement Learning Model for Sodium Appetite. Front Neurosci 2022; 16:857009. [PMID: 35663557 PMCID: PMC9160331 DOI: 10.3389/fnins.2022.857009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/15/2022] [Indexed: 11/30/2022] Open
Abstract
Homeostatic control with oral nutrient intake is a vital complex system involving the orderly interactions between the external and internal senses, behavioral control, reward learning, and decision-making. Sodium appetite is a representative system and has been intensively investigated in animal models of homeostatic systems and oral nutrient intake. However, the system-level mechanisms for regulating sodium intake behavior and homeostatic control remain unclear. In the current study, we attempted to provide a mechanistic understanding of sodium appetite behavior by using a computational model, the homeostatic reinforcement learning model, in which homeostatic behaviors are interpreted as reinforcement learning processes. Through simulation experiments, we confirmed that our homeostatic reinforcement learning model successfully reproduced homeostatic behaviors by regulating sodium appetite. These behaviors include the approach and avoidance behaviors to sodium according to the internal states of individuals. In addition, based on the assumption that the sense of taste is a predictor of changes in the internal state, the homeostatic reinforcement learning model successfully reproduced the previous paradoxical observations of the intragastric infusion test, which cannot be explained by the classical drive reduction theory. Moreover, we extended the homeostatic reinforcement learning model to multimodal data, and successfully reproduced the behavioral tests in which water and sodium appetite were mediated by each other. Finally, through an experimental simulation of chemical manipulation in a specific neural population in the brain stem, we proposed a testable hypothesis for the function of neural circuits involving sodium appetite behavior. The study results support the idea that osmoregulation via sodium appetitive behavior can be understood as a reinforcement learning process, and provide a mechanistic explanation for the underlying neural mechanisms of decision-making related to sodium appetite and homeostatic behavior.
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Affiliation(s)
- Yuuki Uchida
- Department of Information Medicine, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
- Medical and Dental Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takatoshi Hikida
- Laboratory for Advanced Brain Functions, Institute for Protein Research, Osaka University, Osaka, Japan
- *Correspondence: Takatoshi Hikida,
| | - Yuichi Yamashita
- Department of Information Medicine, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
- Yuichi Yamashita,
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9
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Desrochers SS, Spring MG, Nautiyal KM. A Role for Serotonin in Modulating Opposing Drive and Brake Circuits of Impulsivity. Front Behav Neurosci 2022; 16:791749. [PMID: 35250501 PMCID: PMC8892181 DOI: 10.3389/fnbeh.2022.791749] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/11/2022] [Indexed: 12/15/2022] Open
Abstract
Impulsivity generally refers to a deficit in inhibition, with a focus on understanding the neural circuits which constitute the “brake” on actions and gratification. It is likely that increased impulsivity can arise not only from reduced inhibition, but also from a heightened or exaggerated excitatory “drive.” For example, an action which has more vigor, or is fueled by either increased incentive salience or a stronger action-outcome association, may be harder to inhibit. From this perspective, this review focuses on impulse control as a competition over behavioral output between an initially learned response-reward outcome association, and a subsequently acquired opposing inhibitory association. Our goal is to present a synthesis of research from humans and animal models that supports this dual-systems approach to understanding the behavioral and neural substrates that contribute to impulsivity, with a focus on the neuromodulatory role of serotonin. We review evidence for the role of serotonin signaling in mediating the balance of the “drive” and “brake” circuits. Additionally, we consider parallels of these competing instrumental systems in impulsivity within classical conditioning processes (e.g., extinction) in order to point us to potential behavioral and neural mechanisms that may modulate the competing instrumental associations. Finally, we consider how the balance of these competing associations might contribute to, or be extracted from, our experimental assessments of impulsivity. A careful understanding of the underlying behavioral and circuit level contributions to impulsivity is important for understanding the pathogenesis of increased impulsivity present in a number of psychiatric disorders. Pathological levels of impulsivity in such disorders are likely subserved by deficits in the balance of motivational and inhibitory processes.
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10
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Fennis BM, Gineikiene J, Barauskaite D, van Koningsbruggen GM. Acute stress can boost and buffer hedonic consumption: The role of individual differences in consumer life history strategies. PERSONALITY AND INDIVIDUAL DIFFERENCES 2022. [DOI: 10.1016/j.paid.2021.111261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Torske A, Koch K, Eickhoff S, Freiherr J. Localizing the human brain response to olfactory stimulation: A meta-analytic approach. Neurosci Biobehav Rev 2021; 134:104512. [PMID: 34968523 DOI: 10.1016/j.neubiorev.2021.12.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/18/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
The human sense of smell and the ability to detect and distinguish odors allows for the extraction of valuable information from the environment, thereby driving human behavior. Not only can the sense of smell help to monitor the safety of inhaled air, but it can also help to evaluate the edibility of food. Therefore, in an effort to further our understanding of the human sense of smell, the aim of this meta-analysis was to provide the scientific community with activation probability maps of the functional anatomy of the olfactory system, in addition to separate activation maps for specific odor categories (pleasant, food, and aversive odors). The activation likelihood estimation (ALE) method was utilized to quantify all relevant and available data to perform a formal statistical analysis on the inter-study concordance of various odor categories. A total of 81 studies (108 contrasts, 1053 foci) fulfilled our inclusion criteria. Significant ALE peaks were observed in all odor categories in brain areas typically associated with the functional neuroanatomy of olfaction including the piriform cortex, amygdala, insula, and orbitofrontal cortex, amongst others. Additional contrast analyses indicate clear differences in neural activation patterns between odor categories.
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Affiliation(s)
- A Torske
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Technical University of Munich, Germany; Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, Technical University of Munich, Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig Maximilians Universität München, Martinsried, Germany
| | - K Koch
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Technical University of Munich, Germany; Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, Technical University of Munich, Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig Maximilians Universität München, Martinsried, Germany
| | - S Eickhoff
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Institute of Neuroscience and Medicine, Brain & Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
| | - J Freiherr
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany; Institute for Process Engineering and Packaging IVV, Sensory Analytics and Technologies, Fraunhofer Freising, Germany.
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12
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The role of the nucleus accumbens and ventral pallidum in feeding and obesity. Prog Neuropsychopharmacol Biol Psychiatry 2021; 111:110394. [PMID: 34242717 DOI: 10.1016/j.pnpbp.2021.110394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/31/2021] [Accepted: 06/29/2021] [Indexed: 02/04/2023]
Abstract
Obesity is a growing global epidemic that stems from the increasing availability of highly-palatable foods and the consequent enhanced calorie consumption. Extensive research has shown that brain regions that are central to reward seeking modulate feeding and evidence linking obesity to pathology in such regions have recently started to accumulate. In this review we focus on the contribution of two major interconnected structures central to reward processing, the nucleus accumbens and the ventral pallidum, to obesity. We first review the known literature linking these structures to feeding behavior, then discuss recent advances connecting pathology in the nucleus accumbens and ventral pallidum to obesity, and finally examine the similarities and differences between drug addiction and obesity in the context of these two structures. The understanding of how pathology in brain regions involved in reward seeking and consumption may drive obesity and how mechanistically similar obesity and addiction are, is only now starting to be revealed. We hope that future research will advance knowledge in the field and open new avenues to studying and treating obesity.
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13
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Chen Y. Neural Representation of Costs and Rewards in Decision Making. Brain Sci 2021; 11:1096. [PMID: 34439715 PMCID: PMC8391424 DOI: 10.3390/brainsci11081096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022] Open
Abstract
Decision making is crucial for animal survival because the choices they make based on their current situation could influence their future rewards and could have potential costs. This review summarises recent developments in decision making, discusses how rewards and costs could be encoded in the brain, and how different options are compared such that the most optimal one is chosen. The reward and cost are mainly encoded by the forebrain structures (e.g., anterior cingulate cortex, orbitofrontal cortex), and their value is updated through learning. The recent development on dopamine and the lateral habenula's role in reporting prediction errors and instructing learning will be emphasised. The importance of dopamine in powering the choice and accounting for the internal state will also be discussed. While the orbitofrontal cortex is the place where the state values are stored, the anterior cingulate cortex is more important when the environment is volatile. All of these structures compare different attributes of the task simultaneously, and the local competition of different neuronal networks allows for the selection of the most appropriate one. Therefore, the total value of the task is not encoded as a scalar quantity in the brain but, instead, as an emergent phenomenon, arising from the computation at different brain regions.
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Affiliation(s)
- Yixuan Chen
- Queens' College, University of Cambridge, Cambridgeshire CB3 9ET, UK
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14
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Mapping excessive "disgust" in the brain: Ventral pallidum inactivation recruits distributed circuitry to make sweetness "disgusting". COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2021; 20:141-159. [PMID: 31836960 DOI: 10.3758/s13415-019-00758-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The ventral pallidum (VP) is an important structure in processing reward. The VP may be the only brain structure where localized lesions in rats replace normal facial "liking" expressions to sweetness with excessive "disgust" reactions, such as gapes and chin rubs, that are normally reserved for unpalatable tastes. The posterior half of the VP (pVP) contains a hedonic hot spot where opioid or related neurochemical stimulations can amplify positive "liking" reactions to sweet taste. This is the same site where lesions or pharmacological inactivations replace positive hedonic reactions to sucrose with intense negative "disgust." In the present study, we aimed to identify brain networks recruited by pVP inactivation to generate excessive "disgust," using neuronal Fos expression as a marker of neurobiological activation. Microinjections in pVP of inhibitory GABAA/B agonists (muscimol and baclofen) caused rats to exhibit excessive "disgust" reactions to sucrose. Excessive "disgust" was accompanied by recruitment of neural Fos activation in several subcortical structures, including the posterior medial shell of nucleus accumbens (which also contains another GABAergic "disgust"-inducing "hedonic cold spot"), the bed nucleus of stria terminalis, lateral habenula, hypothalamus, and midbrain ventral tegmentum. Fos suppression was found in cortical limbic regions, including previously identified hedonic hot spots in the anteromedial orbitofrontal cortex and posterior insula. Finally, in addition to inducing excessive "disgust," pVP inactivation abolished motivational "wanting" to eat palatable food, reduced positive social interactions, and reordered sensorimotor relations. Our findings identify potential "disgust" generators in the brain that are released into excitation by pVP inhibition and may serve as targets for future research.
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15
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Hegedüs P, Heckenast J, Hangya B. Differential recruitment of ventral pallidal e-types by behaviorally salient stimuli during Pavlovian conditioning. iScience 2021; 24:102377. [PMID: 33912818 PMCID: PMC8066429 DOI: 10.1016/j.isci.2021.102377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/22/2021] [Accepted: 03/26/2021] [Indexed: 10/25/2022] Open
Abstract
The ventral pallidum (VP) is interfacing striatopallidal and limbic circuits, conveying information about salience and valence crucial to adjusting behavior. However, how VP neuron populations with distinct electrophysiological properties (e-types) represent these variables is not fully understood. Therefore, we trained mice on probabilistic Pavlovian conditioning while recording the activity of VP neurons. Many VP neurons responded to punishment (54%), reward (48%), and outcome-predicting auditory stimuli (32%), increasingly differentiating distinct outcome probabilities through learning. We identified e-types based on the presence of bursts or fast rhythmic discharges and found that non-bursting, non-rhythmic neurons were the most sensitive to reward and punishment. Some neurons exhibited distinct responses of their bursts and single spikes, suggesting a multiplexed coding scheme in the VP. Finally, we demonstrate synchronously firing neuron assemblies, particularly responsive to reinforcing stimuli. These results suggest that electrophysiologically defined e-types of the VP differentially participate in transmitting reinforcement signals during learning.
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Affiliation(s)
- Panna Hegedüs
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest 1083, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest 1085, Hungary
| | - Julia Heckenast
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest 1083, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest 1083, Hungary
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16
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Moaddab M, Ray MH, McDannald MA. Ventral pallidum neurons dynamically signal relative threat. Commun Biol 2021; 4:43. [PMID: 33420332 PMCID: PMC7794503 DOI: 10.1038/s42003-020-01554-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
The ventral pallidum (VP) is anatomically poised to contribute to threat behavior. Recent studies report a VP population that scales firing increases to reward but decreases firing to aversive cues. Here, we tested whether firing decreases in VP neurons serve as a neural signal for relative threat. Single-unit activity was recorded while male rats discriminated cues predicting unique foot shock probabilities. Rats' behavior and VP single-unit firing discriminated danger, uncertainty, and safety cues. Two populations of VP neurons dynamically signaled relative threat, decreasing firing according to foot shock probability during early cue presentation, but disproportionately decreasing firing to uncertain threat as foot shock drew near. One relative threat population increased firing to reward, consistent with a bi-directional signal for general value. The second population was unresponsive to reward, revealing a specific signal for relative threat. The results reinforce anatomy to reveal the VP as a neural source of a dynamic, relative threat signal.
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Affiliation(s)
- Mahsa Moaddab
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue 514 McGuinn Hall, Chestnut Hill, MA, USA.
| | - Madelyn H Ray
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue 514 McGuinn Hall, Chestnut Hill, MA, USA
| | - Michael A McDannald
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue 514 McGuinn Hall, Chestnut Hill, MA, USA.
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17
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Metaplasticity in the Ventral Pallidum as a Potential Marker for the Propensity to Gain Weight in Chronic High-Calorie Diet. J Neurosci 2020; 40:9725-9735. [PMID: 33199503 DOI: 10.1523/jneurosci.1809-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 12/30/2022] Open
Abstract
A major driver of obesity is the increasing palatability of processed foods. Although reward circuits promote the consumption of palatable food, their involvement in obesity remains unclear. The ventral pallidum (VP) is a key hub in the reward system that encodes the hedonic aspects of palatable food consumption and participates in various proposed feeding circuits. However, there is still no evidence for its involvement in developing diet-induced obesity. Here we examine, using male C57BL6/J mice and patch-clamp electrophysiology, how chronic high-fat high-sugar (HFHS) diet changes the physiology of the VP and whether mice that gain the most weight differ in their VP physiology from others. We found that 10-12 weeks of HFHS diet hyperpolarized and decreased the firing rate of VP neurons without a major change in synaptic inhibitory input. Within the HFHS group, the top 33% weight gainers (WGs) had a more hyperpolarized VP with longer latency to fire action potentials on depolarization compared with bottom 33% of weight gainers (i.e., non-weight gainers). WGs also showed synaptic potentiation of inhibitory inputs both at the millisecond and minute ranges. Moreover, we found that the tendency to potentiate the inhibitory inputs to the VP might exist in overeating mice even before exposure to HFHS, thus making it a potential property of being an overeater. These data point to the VP as a critical player in obesity and suggest that hyperpolarized membrane potential of, and potentiated inhibitory inputs to, VP neurons may play a significant role in promoting the overeating of palatable food.SIGNIFICANCE STATEMENT In modern world, where highly palatable food is readily available, overeating is often driven by motivational, rather than metabolic, needs. It is thus conceivable that reward circuits differ between obese and normal-weight individuals. But is such difference, if it exists, innate or does it develop with overeating? Here we reveal synaptic properties in the ventral pallidum, a central hub of reward circuits, that differ between mice that gain the most and the least weight when given unlimited access to highly palatable food. We show that these synaptic differences also exist without exposure to palatable food, potentially making them innate properties that render some more susceptible than others to overeat. Thus, the propensity to overeat may have a strong innate component embedded in reward circuits.
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18
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Morales I, Berridge KC. 'Liking' and 'wanting' in eating and food reward: Brain mechanisms and clinical implications. Physiol Behav 2020; 227:113152. [PMID: 32846152 PMCID: PMC7655589 DOI: 10.1016/j.physbeh.2020.113152] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 01/02/2023]
Abstract
It is becoming clearer how neurobiological mechanisms generate 'liking' and 'wanting' components of food reward. Mesocorticolimbic mechanisms that enhance 'liking' include brain hedonic hotspots, which are specialized subregions that are uniquely able to causally amplify the hedonic impact of palatable tastes. Hedonic hotspots are found in nucleus accumbens medial shell, ventral pallidum, orbitofrontal cortex, insula cortex, and brainstem. In turn, a much larger mesocorticolimbic circuitry generates 'wanting' or incentive motivation to obtain and consume food rewards. Hedonic and motivational circuitry interact together and with hypothalamic homeostatic circuitry, allowing relevant physiological hunger and satiety states to modulate 'liking' and 'wanting' for food rewards. In some conditions such as drug addiction, 'wanting' is known to dramatically detach from 'liking' for the same reward, and this may also occur in over-eating disorders. Via incentive sensitization, 'wanting' selectively becomes higher, especially when triggered by reward cues when encountered in vulnerable states of stress, etc. Emerging evidence suggests that some cases of obesity and binge eating disorders may reflect an incentive-sensitization brain signature of cue hyper-reactivity, causing excessive 'wanting' to eat. Future findings on the neurobiological bases of 'liking' and 'wanting' can continue to improve understanding of both normal food reward and causes of clinical eating disorders.
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Affiliation(s)
- Ileana Morales
- Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109-1043, United States.
| | - Kent C Berridge
- Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109-1043, United States
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19
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Ottenheimer DJ, Wang K, Tong X, Fraser KM, Richard JM, Janak PH. Reward activity in ventral pallidum tracks satiety-sensitive preference and drives choice behavior. SCIENCE ADVANCES 2020; 6:6/45/eabc9321. [PMID: 33148649 PMCID: PMC7673692 DOI: 10.1126/sciadv.abc9321] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
A key function of the nervous system is producing adaptive behavior across changing conditions, like physiological state. Although states like thirst and hunger are known to impact decision-making, the neurobiology of this phenomenon has been studied minimally. Here, we tracked evolving preference for sucrose and water as rats proceeded from a thirsty to sated state. As rats shifted from water choices to sucrose choices across the session, the activity of a majority of neurons in the ventral pallidum, a region crucial for reward-related behaviors, closely matched the evolving behavioral preference. The timing of this signal followed the pattern of a reward prediction error, occurring at the cue or the reward depending on when reward identity was revealed. Additionally, optogenetic stimulation of ventral pallidum neurons at the time of reward was able to reverse behavioral preference. Our results suggest that ventral pallidum neurons guide reward-related decisions across changing physiological states.
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Affiliation(s)
- David J Ottenheimer
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Karen Wang
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Xiao Tong
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Kurt M Fraser
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Jocelyn M Richard
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Patricia H Janak
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
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20
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Projections from the nucleus accumbens shell to the ventral pallidum are involved in the control of sucrose intake in adult female rats. Brain Struct Funct 2020; 225:2815-2839. [PMID: 33124673 DOI: 10.1007/s00429-020-02161-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/15/2020] [Indexed: 12/28/2022]
Abstract
In rodents, stimulation of the nucleus accumbens shell (AcbSh) directly or via its projection to the lateral hypothalamus (LH) attenuates food intake. The ventral pallidum (VP) receives dense projections from the AcbSh and is sensitive to the hedonic aspect of food and motivation for reward. However, the role of accumbal projections to the VP in the regulation of food intake was not well investigated. In the present study conducted on female rats, we examined the effects of stimulation of the AcbSh using optogenetics, or pharmacological inhibition of the rostral VP, or stimulation of projections from the AcbSh to the rostral VP using optogenetics on the consumption of 10% sucrose, lick microstructure and the expression of c-fos mRNA. Stimulation of the AcbSh, inhibition of the rostral VP with muscimol, or stimulation of axonal terminals from the AcbSh to the rostral VP resulted in a decrease in sucrose intake, meal duration, and total number of licks. The licking microstructure analysis showed that optogenetic stimulation of AcbSh or axonal terminals from the AcbSh to the rostral VP decreased the hedonic value of the sucrose. However, inhibition of the rostral VP decreased the motivation, whereas stimulation of the accumbal projections in the rostral VP increased the motivation to drink. This difference could be due to differential involvement of GABAergic and glutamatergic VP neurons. Stimulation of the AcbSh resulted in a decrease of c-fos mRNA expression in the LH and rostral VP, and stimulation of axonal terminals from the AcbSh to the rostral VP decreased c-fos mRNA expression only in the rostral VP. This study demonstrates that in adult female rats, in addition to the already known role of the AcbSh projections to the LH, AcbSh projections to the VP play a major role in the regulation of sucrose intake.
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Abstract
The prevalence of obesity in children and adolescents worldwide has quadrupled since 1975 and is a key predictor of obesity later in life. Previous work has consistently observed relationships between macroscale measures of reward-related brain regions (e.g., the nucleus accumbens [NAcc]) and unhealthy eating behaviors and outcomes; however, the mechanisms underlying these associations remain unclear. Recent work has highlighted a potential role of neuroinflammation in the NAcc in animal models of diet-induced obesity. Here, we leverage a diffusion MRI technique, restriction spectrum imaging, to probe the microstructure (cellular density) of subcortical brain regions. More specifically, we test the hypothesis that the cell density of reward-related regions is associated with obesity-related metrics and early weight gain. In a large cohort of nine- and ten-year-olds enrolled in the Adolescent Brain Cognitive Development (ABCD) study, we demonstrate that cellular density in the NAcc is related to individual differences in waist circumference at baseline and is predictive of increases in waist circumference after 1 y. These findings suggest a neurobiological mechanism for pediatric obesity consistent with rodent work showing that high saturated fat diets increase gliosis and neuroinflammation in reward-related brain regions, which in turn lead to further unhealthy eating and obesity.
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Jackson K, Jansen E, Mallan KM. Examining child intake frequency, mothers' own liking and child early exposure as potential predictors of child liking for restricted foods and drinks at 5 years old. Public Health Nutr 2020; 23:2355-2364. [PMID: 32524934 PMCID: PMC11374564 DOI: 10.1017/s1368980020000312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To examine longitudinal patterns of child introduction to foods and drinks targeted for restriction by parents and associations between child intake frequency, mother's own liking, child early exposure and child liking for restricted foods and drinks at 5 years old. DESIGN The study involved secondary analyses of longitudinal data from mothers and children participating in the NOURISH randomised controlled trial. Patterns of descriptive data were examined, and a binary logistic regression model tested for prediction of child liking of a selection of restricted foods and drinks. SETTING Brisbane and Adelaide, Australia. PARTICIPANTS Two hundred and eleven mothers and their first born 5-year-old children. RESULTS The proportion of children who had tried the selected restricted foods and drinks progressively increased from 14 months to 5 years old. Mothers' own high liking for both sweet and savoury restricted foods and drinks predicted child high liking for the same items at 5 years old. Child high intake frequency at 5 years old also predicted child high liking for sweet foods and drinks, but child early exposure did not predict child liking for the restricted items examined. CONCLUSIONS These results challenge the belief that limiting children's intake of foods high in sugar, fat and/or salt will increase their liking for them. Findings instead suggest that restricting children's access to such foods may be beneficial. While further research is required, mothers should be made aware that their own food preferences may inadvertently influence their child's liking for the very foods they are trying to restrict.
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Affiliation(s)
- Kim Jackson
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland4059, Australia
| | - Elena Jansen
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland4059, Australia
| | - Kimberley M Mallan
- School of Behavioural and Health Sciences, Australian Catholic University, Brisbane, Queensland, Australia
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23
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Prasad AA, McNally GP. The ventral pallidum and relapse in alcohol seeking. Br J Pharmacol 2020; 177:3855-3864. [PMID: 32557550 DOI: 10.1111/bph.15160] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/29/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022] Open
Abstract
Alcohol-use disorders are chronically relapsing conditions characterized by cycles of use, abstinence and relapse. The ventral pallidum (VP) is a key node in the neural circuits controlling relapse to alcohol seeking and a key target of pharmacotherapies for relapse prevention. There has been a significant increase in our understanding of the molecular, anatomical, pharmacological and functional properties of the ventral pallidum, laying foundations for a new understanding of its role in relapse to alcohol seeking and motivation. Here we review these advances, placing special emphasis on how advances in understanding in the cellular and circuit architectures of ventral pallidum contributes to the relapse to alcohol seeking. We show how this knowledge improves mechanistic understanding of current relapse prevention pharmacotherapies, how it may be used to tailor these against different forms of relapse and how it may help provide insights into the mental health problems frequently co-morbid with alcohol-use disorders.
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24
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Gasparini S, Howland JM, Thatcher AJ, Geerling JC. Central afferents to the nucleus of the solitary tract in rats and mice. J Comp Neurol 2020; 528:2708-2728. [PMID: 32307700 DOI: 10.1002/cne.24927] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
Abstract
The nucleus of the solitary tract (NTS) regulates life-sustaining functions ranging from appetite and digestion to heart rate and breathing. It is also the brain's primary sensory nucleus for visceral sensations relevant to symptoms in medical and psychiatric disorders. To better understand which neurons may exert top-down control over the NTS, here we provide a brain-wide map of all neurons that project axons directly to the caudal, viscerosensory NTS, focusing on a medial subregion with aldosterone-sensitive HSD2 neurons. Injecting an axonal tracer (cholera toxin b) into the NTS produces a similar pattern of retrograde labeling in rats and mice. The paraventricular hypothalamic nucleus (PVH), lateral hypothalamic area, and central nucleus of the amygdala (CeA) contain the densest concentrations of NTS-projecting neurons. PVH afferents are glutamatergic (express Slc17a6/Vglut2) and are distinct from neuroendocrine PVH neurons. CeA afferents are GABAergic (express Slc32a1/Vgat) and are distributed largely in the medial CeA subdivision. Other retrogradely labeled neurons are located in a variety of brain regions, including the cerebral cortex (insular and infralimbic areas), bed nucleus of the stria terminalis, periaqueductal gray, Barrington's nucleus, Kölliker-Fuse nucleus, hindbrain reticular formation, and rostral NTS. Similar patterns of retrograde labeling result from tracer injections into different NTS subdivisions, with dual retrograde tracing revealing that many afferent neurons project axon collaterals to both the lateral and medial NTS subdivisions. This information provides a roadmap for studying descending axonal projections that may influence visceromotor systems and visceral "mind-body" symptoms.
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Affiliation(s)
- Silvia Gasparini
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Jacob M Howland
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Andrew J Thatcher
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Joel C Geerling
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
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25
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Inbar K, Levi LA, Bernat N, Odesser T, Inbar D, Kupchik YM. Cocaine Dysregulates Dynorphin Modulation of Inhibitory Neurotransmission in the Ventral Pallidum in a Cell-Type-Specific Manner. J Neurosci 2020; 40:1321-1331. [PMID: 31836660 PMCID: PMC7002149 DOI: 10.1523/jneurosci.1262-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 11/21/2022] Open
Abstract
Cocaine-driven changes in the modulation of neurotransmission by neuromodulators are poorly understood. The ventral pallidum (VP) is a key structure in the reward system, in which GABA neurotransmission is regulated by opioid neuropeptides, including dynorphin. However, it is not known whether dynorphin acts differently on different cell types in the VP and whether its effects are altered by withdrawal from cocaine. Here, we trained wild-type, D1-Cre, A2A-Cre, or vGluT2-Cre:Ai9 male and female mice in a cocaine conditioned place preference protocol followed by 2 weeks of abstinence, and then recorded GABAergic synaptic input evoked either electrically or optogenetically onto identified VP neurons before and after applying dynorphin. We found that after cocaine CPP and abstinence dynorphin attenuated inhibitory input to VPGABA neurons through a postsynaptic mechanism. This effect was absent in saline mice. Furthermore, this effect was seen specifically on the inputs from nucleus accumbens medium spiny neurons expressing either the D1 or the D2 dopamine receptor. Unlike its effect on VPGABA neurons, dynorphin surprisingly potentiated the inhibitory input on VPvGluT2 neurons, but this effect was abolished after cocaine CPP and abstinence. Thus, dynorphin has contrasting influences on GABA input to VPGABA and VPvGluT2 neurons and these influences are affected differentially by cocaine CPP and abstinence. Collectively, our data suggest a role for dynorphin in withdrawal through its actions in the VP. As VPGABA and VPvGluT2 neurons have contrasting effects on drug-seeking behavior, our data may indicate a complex role for dynorphin in withdrawal from cocaine.SIGNIFICANCE STATEMENT The ventral pallidum consists mainly of GABAergic reward-promoting neurons, but it also encloses a subgroup of aversion-promoting glutamatergic neurons. Dynorphin, an opioid neuropeptide abundant in the ventral pallidum, shows differential modulation of GABA input to GABAergic and glutamatergic pallidal neurons and may therefore affect both the rewarding and aversive aspects of withdrawal. Indeed, abstinence after repeated exposure to cocaine alters dynorphin actions in a cell-type-specific manner; after abstinence dynorphin suppresses the inhibitory drive on the "rewarding" GABAergic neurons but ceases to modulate the inhibitory drive on the "aversive" glutamatergic neurons. This reflects a complex role for dynorphin in cocaine reward and abstinence.
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Affiliation(s)
- Kineret Inbar
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
| | - Liran A Levi
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
| | - Nimrod Bernat
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
| | - Tal Odesser
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
| | - Dorrit Inbar
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
| | - Yonatan M Kupchik
- Department of Medical Neurobiology, Faculty of Medicine, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Israel 9112102
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Stephenson-Jones M, Bravo-Rivera C, Ahrens S, Furlan A, Xiao X, Fernandes-Henriques C, Li B. Opposing Contributions of GABAergic and Glutamatergic Ventral Pallidal Neurons to Motivational Behaviors. Neuron 2020; 105:921-933.e5. [PMID: 31948733 DOI: 10.1016/j.neuron.2019.12.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 09/23/2019] [Accepted: 12/04/2019] [Indexed: 01/05/2023]
Abstract
The ventral pallidum (VP) is critical for invigorating reward seeking and is also involved in punishment avoidance, but how it contributes to such opposing behavioral actions remains unclear. Here, we show that GABAergic and glutamatergic VP neurons selectively control behavior in opposing motivational contexts. In vivo recording combined with optogenetics in mice revealed that these two populations oppositely encode positive and negative motivational value, are differentially modulated by animal's internal state, and determine the behavioral response during motivational conflict. Furthermore, GABAergic VP neurons are essential for movements toward reward in a positive motivational context but suppress movements in an aversive context. In contrast, glutamatergic VP neurons are essential for movements to avoid a threat but suppress movements in an appetitive context. Our results indicate that GABAergic and glutamatergic VP neurons encode the drive for approach and avoidance, respectively, with the balance between their activities determining the type of motivational behavior.
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Affiliation(s)
| | | | - Sandra Ahrens
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | - Xiong Xiao
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | - Bo Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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27
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Projection-Specific Potentiation of Ventral Pallidal Glutamatergic Outputs after Abstinence from Cocaine. J Neurosci 2019; 40:1276-1285. [PMID: 31836662 DOI: 10.1523/jneurosci.0929-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 12/18/2022] Open
Abstract
The ventral pallidum (VP) is a central node in the reward system that is strongly implicated in reward and addiction. Although the majority of VP neurons are GABAergic and encode reward, recent studies revealed a novel glutamatergic neuronal population in the VP [VP neurons expressing the vesicular glutamate transporter 2 (VPVGluT2)], whose activation generates aversion. Withdrawal from drugs has been shown to induce drastic synaptic changes in neuronal populations associated with reward, such as the ventral tegmental area (VTA) or nucleus accumbens neurons, but less is known about cocaine-induced synaptic changes in neurons classically linked with aversion. Here, we demonstrate that VPVGluT2 neurons contact different targets with different intensities, and that cocaine conditioned place preference (CPP) training followed by abstinence selectively potentiates their synapses on targets that encode aversion. Using whole-cell patch-clamp recordings combined with optogenetics in male and female transgenic mice, we show that VPVGluT2 neurons preferentially contact aversion-related neurons, such as lateral habenula neurons and VTA GABAergic neurons, with minor input to reward-related neurons, such as VTA dopamine and VP GABA neurons. Moreover, after cocaine CPP and abstinence, the VPVGluT2 input to the aversion-related structures is potentiated, whereas the input to the reward-related structures is depressed. Thus, cocaine CPP followed by abstinence may allow VPVGluT2 neurons to recruit aversion-related targets more readily and therefore be part of the mechanism underlying the aversive symptoms seen after withdrawal.SIGNIFICANCE STATEMENT The biggest problem in drug addiction is the high propensity to relapse. One central driver for relapse events is the negative aversive symptoms experienced by addicts during withdrawal. In this work, we propose a possible mechanism for the intensification of aversive feelings after withdrawal that involves the glutamatergic neurons of the ventral pallidum. We show not only that these neurons are most strongly connected to aversive targets, such as the lateral habenula, but also that, after abstinence, their synapses on aversive targets are strengthened, whereas the synapses on other rewarding targets are weakened. These data illustrate how after abstinence from cocaine, aversive pathways change in a manner that may contribute to relapse.
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28
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Ahrens AM, Ahmed OJ. Neural circuits linking sleep and addiction: Animal models to understand why select individuals are more vulnerable to substance use disorders after sleep deprivation. Neurosci Biobehav Rev 2019; 108:435-444. [PMID: 31756346 DOI: 10.1016/j.neubiorev.2019.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 10/26/2019] [Accepted: 11/12/2019] [Indexed: 12/12/2022]
Abstract
Individuals differ widely in their drug-craving behaviors. One reason for these differences involves sleep. Sleep disturbances lead to an increased risk of substance use disorders and relapse in only some individuals. While animal studies have examined the impact of sleep on reward circuitry, few have addressed the role of individual differences in the effects of altered sleep. There does, however, exist a rodent model of individual differences in reward-seeking behavior: the sign/goal-tracker model of Pavlovian conditioned approach. In this model, only some rats show the key behavioral traits associated with addiction, including impulsivity and poor attentional control, making this an ideal model system to examine individually distinct sleep-reward interactions. Here, we describe how the limbic neural circuits responsible for individual differences in incentive motivation overlap with those involved in sleep-wake regulation, and how this model can elucidate the common underlying mechanisms. Consideration of individual differences in preclinical models would improve our understanding of how sleep interacts with motivational systems, and why sleep deprivation contributes to addiction in only select individuals.
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Affiliation(s)
| | - Omar J Ahmed
- Dept. of Psychology, United States; Neuroscience Graduate Program, United States; Michigan Center for Integrative Research in Critical Care, United States; Kresge Hearing Research Institute, United States; Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States.
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29
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Kennedy JT, Astafiev SV, Golosheykin S, Korucuoglu O, Anokhin AP. Shared genetic influences on adolescent body mass index and brain structure: A voxel-based morphometry study in twins. Neuroimage 2019; 199:261-272. [PMID: 31163268 DOI: 10.1016/j.neuroimage.2019.05.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 05/17/2019] [Accepted: 05/19/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Previous research has demonstrated significant relationships between obesity and brain structure. Both phenotypes are heritable, but it is not known whether they are influenced by common genetic factors. We investigated the genetic etiology of the relationship between individual variability in brain morphology and BMIz using structural MRI in adolescent twins. METHOD The sample (n = 258) consisted of 54 monozygotic and 75 dizygotic twin pairs (mean(SD) age = 13.61(0.505), BMIz = 0.608(1.013). Brain structure (volume and density of gray and white matter) was assessed using VBM. Significant voxelwise heritability of brain structure was established using the Accelerated Permutation inference for ACE models (APACE) program, with structural heritability varying from 15 to 97%, depending on region. Bivariate heritability analyses were carried out comparing additive genetic and unique environment models with and without shared genetics on BMIz and the voxels showing significant heritability in the APACE analyses. RESULTS BMIz was positively related to gray matter volume in the brainstem and thalamus and negatively related to gray matter volume in the bilateral uncus and medial orbitofrontal cortex, gray matter density in the cerebellum, prefrontal lobe, temporal lobe, and limbic system, and white matter density in the brainstem. Bivariate heritability analyses showed that BMIz and brain structure share ∼1/3 of their genes and that ∼95% of the phenotypic correlation between BMIz and brain structure is due to shared additive genetic influences. These regions included areas related to decision-making, motivation, liking vs. wanting, taste, interoception, reward processing/learning, caloric evaluation, and inhibition. CONCLUSION These results suggested genetic factors are responsible for the relationship between BMIz and heritable BMIz related brain structure in areas related to eating behavior.
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Affiliation(s)
- James T Kennedy
- Department of Psychiatry, Washington University School of Medicine, United States.
| | - Serguei V Astafiev
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Semyon Golosheykin
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Ozlem Korucuoglu
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Andrey P Anokhin
- Department of Psychiatry, Washington University School of Medicine, United States
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Yohn SE, Galbraith J, Calipari ES, Conn PJ. Shared Behavioral and Neurocircuitry Disruptions in Drug Addiction, Obesity, and Binge Eating Disorder: Focus on Group I mGluRs in the Mesolimbic Dopamine Pathway. ACS Chem Neurosci 2019; 10:2125-2143. [PMID: 30933466 PMCID: PMC7898461 DOI: 10.1021/acschemneuro.8b00601] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Accumulated data from clinical and preclinical studies suggest that, in drug addiction and states of overeating, such as obesity and binge eating disorder (BED), there is an imbalance in circuits that are critical for motivation, reward saliency, executive function, and self-control. Central to these pathologies and the extensive topic of this Review are the aberrations in dopamine (DA) and glutamate (Glu) within the mesolimbic pathway. Group I metabotropic glutamate receptors (mGlus) are highly expressed in the mesolimbic pathway and are poised in key positions to modulate disruptions in synaptic plasticity and neurotransmitter release observed in drug addiction, obesity, and BED. The use of allosteric modulators of group I mGlus has been studied in drug addiction, as they offer several advantages over traditional orthosteric agents. However, they have yet to be studied in obesity or BED. With the substantial overlap between the neurocircuitry involved in drug addiction and eating disorders, group I mGlus may also provide novel targets for obesity and BED.
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Affiliation(s)
- Samantha E. Yohn
- Department of Pharmacology, Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, United States
| | - Jordan Galbraith
- Department of Pharmacology, Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, United States
| | - Erin S. Calipari
- Department of Pharmacology, Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, United States
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Social motivation in autism: Gaps and directions for measurement of a putative core construct. Behav Brain Sci 2019. [DOI: 10.1017/s0140525x18002418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
This commentary highlights the observation that social motivation is usually an imprecisely specified construct. We suggest four social motivation conceptualizations across levels of analysis and explore where the target article situates among these. We then offer theoretical and practical guidance for operationalization and measurement of social motivation to support more comprehensive future research on this complex construct in the autism literature.
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33
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Schier LA, Spector AC. The Functional and Neurobiological Properties of Bad Taste. Physiol Rev 2019; 99:605-663. [PMID: 30475657 PMCID: PMC6442928 DOI: 10.1152/physrev.00044.2017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/18/2018] [Accepted: 06/30/2018] [Indexed: 12/12/2022] Open
Abstract
The gustatory system serves as a critical line of defense against ingesting harmful substances. Technological advances have fostered the characterization of peripheral receptors and have created opportunities for more selective manipulations of the nervous system, yet the neurobiological mechanisms underlying taste-based avoidance and aversion remain poorly understood. One conceptual obstacle stems from a lack of recognition that taste signals subserve several behavioral and physiological functions which likely engage partially segregated neural circuits. Moreover, although the gustatory system evolved to respond expediently to broad classes of biologically relevant chemicals, innate repertoires are often not in register with the actual consequences of a food. The mammalian brain exhibits tremendous flexibility; responses to taste can be modified in a specific manner according to bodily needs and the learned consequences of ingestion. Therefore, experimental strategies that distinguish between the functional properties of various taste-guided behaviors and link them to specific neural circuits need to be applied. Given the close relationship between the gustatory and visceroceptive systems, a full reckoning of the neural architecture of bad taste requires an understanding of how these respective sensory signals are integrated in the brain.
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Affiliation(s)
- Lindsey A Schier
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Alan C Spector
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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34
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Browne CA, Hammack R, Lucki I. Dysregulation of the Lateral Habenula in Major Depressive Disorder. Front Synaptic Neurosci 2018; 10:46. [PMID: 30581384 PMCID: PMC6292991 DOI: 10.3389/fnsyn.2018.00046] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/22/2018] [Indexed: 12/31/2022] Open
Abstract
Clinical and preclinical evidence implicates hyperexcitability of the lateral habenula (LHb) in the development of psychiatric disorders including major depressive disorder (MDD). This discrete epithalamic nucleus acts as a relay hub linking forebrain limbic structures with midbrain aminergic centers. Central to reward processing, learning and goal directed behavior, the LHb has emerged as a critical regulator of the behaviors that are impaired in depression. Stress-induced activation of the LHb produces depressive- and anxiety-like behaviors, anhedonia and aversion in preclinical studies. Moreover, deep brain stimulation of the LHb in humans has been shown to alleviate chronic unremitting depression in treatment resistant depression. The diverse neurochemical processes arising in the LHb that underscore the emergence and treatment of MDD are considered in this review, including recent optogenetic studies that probe the anatomical connections of the LHb.
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Affiliation(s)
- Caroline A Browne
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Robert Hammack
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Irwin Lucki
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Tye KM. Neural Circuit Motifs in Valence Processing. Neuron 2018; 100:436-452. [PMID: 30359607 PMCID: PMC6590698 DOI: 10.1016/j.neuron.2018.10.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/24/2018] [Accepted: 09/28/2018] [Indexed: 01/07/2023]
Abstract
How do our brains determine whether something is good or bad? How is this computational goal implemented in biological systems? Given the critical importance of valence processing for survival, the brain has evolved multiple strategies to solve this problem at different levels. The psychological concept of "emotional valence" is now beginning to find grounding in neuroscience. This review aims to bridge the gap between psychology and neuroscience on the topic of emotional valence processing. Here, I highlight a subset of studies that exemplify circuit motifs that repeatedly appear as implementational systems in valence processing. The motifs I identify as being important in valence processing include (1) Labeled Lines, (2) Divergent Paths, (3) Opposing Components, and (4) Neuromodulatory Gain. Importantly, the functionality of neural substrates in valence processing is dynamic, context-dependent, and changing across short and long timescales due to synaptic plasticity, competing mechanisms, and homeostatic need.
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Affiliation(s)
- Kay M Tye
- Picower Institute for Learning and Memory, Dept of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Salk Institute for Biological Sciences, La Jolla, CA 92037, USA.
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36
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Aldosterone-sensitive HSD2 neurons in mice. Brain Struct Funct 2018; 224:387-417. [PMID: 30343334 DOI: 10.1007/s00429-018-1778-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/03/2018] [Indexed: 02/07/2023]
Abstract
Sodium deficiency elevates aldosterone, which in addition to epithelial tissues acts on the brain to promote dysphoric symptoms and salt intake. Aldosterone boosts the activity of neurons that express 11-beta-hydroxysteroid dehydrogenase type 2 (HSD2), a hallmark of aldosterone-sensitive cells. To better characterize these neurons, we combine immunolabeling and in situ hybridization with fate mapping and Cre-conditional axon tracing in mice. Many cells throughout the brain have a developmental history of Hsd11b2 expression, but in the adult brain one small brainstem region with a leaky blood-brain barrier contains HSD2 neurons. These neurons express Hsd11b2, Nr3c2 (mineralocorticoid receptor), Agtr1a (angiotensin receptor), Slc17a6 (vesicular glutamate transporter 2), Phox2b, and Nxph4; many also express Cartpt or Lmx1b. No HSD2 neurons express cholinergic, monoaminergic, or several other neuropeptidergic markers. Their axons project to the parabrachial complex (PB), where they intermingle with AgRP-immunoreactive axons to form dense terminal fields overlapping FoxP2 neurons in the central lateral subnucleus (PBcL) and pre-locus coeruleus (pLC). Their axons also extend to the forebrain, intermingling with AgRP- and CGRP-immunoreactive axons to form dense terminals surrounding GABAergic neurons in the ventrolateral bed nucleus of the stria terminalis (BSTvL). Sparse axons target the periaqueductal gray, ventral tegmental area, lateral hypothalamic area, paraventricular hypothalamic nucleus, and central nucleus of the amygdala. Dual retrograde tracing revealed that largely separate HSD2 neurons project to pLC/PB or BSTvL. This projection pattern raises the possibility that a subset of HSD2 neurons promotes the dysphoric, anorexic, and anhedonic symptoms of hyperaldosteronism via AgRP-inhibited relay neurons in PB.
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Ventral pallidum encodes relative reward value earlier and more robustly than nucleus accumbens. Nat Commun 2018; 9:4350. [PMID: 30341305 PMCID: PMC6195583 DOI: 10.1038/s41467-018-06849-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/26/2018] [Indexed: 12/21/2022] Open
Abstract
The ventral striatopallidal system, a basal ganglia network thought to convert limbic information into behavioral action, includes the nucleus accumbens (NAc) and the ventral pallidum (VP), typically described as a major output of NAc. Here, to investigate how reward-related information is transformed across this circuit, we measure the activity of neurons in NAc and VP when rats receive two highly palatable but differentially preferred rewards, allowing us to track the reward-specific information contained within the neural activity of each region. In VP, we find a prominent preference-related signal that flexibly reports the relative value of reward outcomes across multiple conditions. This reward-specific firing in VP is present in a greater proportion of the population and arises sooner following reward delivery than in NAc. Our findings establish VP as a preeminent value signaler and challenge the existing model of information flow in the ventral basal ganglia.
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Wulff AB, Tooley J, Marconi LJ, Creed MC. Ventral pallidal modulation of aversion processing. Brain Res 2018; 1713:62-69. [PMID: 30300634 DOI: 10.1016/j.brainres.2018.10.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/27/2018] [Accepted: 10/05/2018] [Indexed: 12/23/2022]
Abstract
Responding to aversive and rewarding stimuli is essential to survival. The ventral pallidum (VP) is a critical node in the mesolimbic network, being the primary output of the nucleus accumbens and projecting to the lateral habenula (LHb) and ventral tegmental area (VTA). The VP is thus poised to modulate the habenula-tegmental circuitry and contribute to processing both rewarding and aversive stimuli. Here, we integrate human functional imaging, behavioral pharmacology in rodents, and recent optogenetic circuit dissection studies of the VP with a focus on the role of the neurochemically-distinct subpopulations in aversion processing. These recent results support a model in which glutamatergic VP neurons play a unique role in aversion processing, while canonical GABAergic VP neurons promote reinforcement and encode the hedonic value of reward. Genetic ablation of glutamatergic, but not GABAergic VP neurons abolishes devaluation of natural reward (sucrose) by pairing with an aversive stimulus (lithium chloride injection). Both of these populations modulate activity throughout the LHb and VTA, which is necessary for expression of adaptive behavior in response to rewarding or aversive stimuli. Future work will address how neuromodulators such as endogenous opioids or dopamine shape function and plasticity within these distinct populations of VP neurons, when these subpopulations are engaged during learning responses to rewarding and aversive stimuli, and how their activity is altered in models of reward-related disorders. Answering these questions will be necessary to understand the basis and ultimately develop targeted therapies for disorders of reward/aversion processing, such as affective, chronic pain and substance use disorders.
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Affiliation(s)
- Andreas B Wulff
- University of Maryland School of Medicine, Department of Pharmacology, United States
| | - Jessica Tooley
- Washington University School of Medicine in St. Louis, Department of Anesthesiology, United States; University of Maryland School of Medicine, Department of Pharmacology, United States
| | - Lauren J Marconi
- University of Maryland School of Medicine, Department of Pharmacology, United States
| | - Meaghan C Creed
- Washington University School of Medicine in St. Louis, Department of Anesthesiology, United States
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Heterogeneous dopamine signals support distinct features of motivated actions: implications for learning and addiction. ACTA ACUST UNITED AC 2018; 25:416-424. [PMID: 30115763 PMCID: PMC6097772 DOI: 10.1101/lm.047019.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/15/2018] [Indexed: 01/05/2023]
Abstract
Despite decades of research, investigations into effective neural and pharmacological therapies for many drugs of abuse, such as cocaine, have produced no FDA-approved approaches. This difficulty derives from the complexity of substance use disorders, which encompass a variety of behavioral, psychological, and neural circuit-based changes that occur as a result of repeated experience with the drug. Dopamine signaling has been demonstrated to play a key role in several aspects of drug abuse—from mediating its reinforcing properties and drug-seeking to triggering relapse—while also mediating a number of important aspects of normal (nondrug related) motivated behaviors and actions. Real-time recording methods such as in vivo voltammetry, electrophysiology, and calcium imaging demonstrate that the signaling properties of dopamine for motivationally relevant stimuli are highly dynamic and spatiotemporally circumscribed within afferent target regions. In this review, we identify the origins and functional consequences of heterogeneous dopamine release in the limbic system, and how these properties are persistently altered in the drug-experienced brain. We propose that these spatiotemporally parallel dopaminergic signals are simultaneously available to the animal, but that these circuits are impaired following prolonged drug experience by disrupting the location and content of dopamine signals in afferent target regions. These findings are discussed in the context of relapse and pathways to discovering new treatments for addiction disorders.
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Tooley J, Marconi L, Alipio JB, Matikainen-Ankney B, Georgiou P, Kravitz AV, Creed MC. Glutamatergic Ventral Pallidal Neurons Modulate Activity of the Habenula-Tegmental Circuitry and Constrain Reward Seeking. Biol Psychiatry 2018; 83:1012-1023. [PMID: 29452828 PMCID: PMC5972062 DOI: 10.1016/j.biopsych.2018.01.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 01/02/2018] [Accepted: 01/04/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND The ability to appropriately integrate and respond to rewarding and aversive stimuli is essential for survival. The ventral pallidum (VP) plays a critical role in processing both rewarding and aversive stimuli. However, the VP is a heterogeneous structure, and how VP subpopulations integrate into larger reward networks to ultimately modulate these behaviors is not known. We identify a noncanonical population of glutamatergic VP neurons that play a unique role in responding to aversive stimuli and constraining inappropriate reward seeking. METHODS Using neurochemical, genetic, and electrophysiological approaches, we characterized glutamatergic VP neurons (n = 4-8 mice/group). We performed patch clamp and in vivo electrophysiology recordings in the lateral habenula, rostromedial tegmental nucleus, and ventral tegmental area to determine the effect of glutamatergic VP neuron activation in these target regions (n = 6-10 mice/group). Finally, we selectively optogenetically stimulated glutamatergic VP neurons in a real-time place preference task and ablated these neurons using a virally expressed caspase to determine their necessity for reward seeking. RESULTS Glutamatergic VP neurons exhibit little overlap with cholinergic or gamma-aminobutyric acidergic markers, the canonical VP subtypes, and exhibit distinct membrane properties. Glutamatergic VP neurons innervate and increase firing activity of the lateral habenula, rostromedial tegmental nucleus, and gamma-aminobutyric acidergic ventral tegmental area neurons. While nonselective optogenetic stimulation of the VP induced a robust place preference, selective activation of glutamatergic VP neurons induced a place avoidance. Viral ablation of glutamatergic VP neurons increased reward responding and abolished taste aversion to sucrose. CONCLUSIONS Glutamatergic VP neurons constitute a noncanonical subpopulation of VP neurons. These glutamatergic VP neurons increase activity of the lateral habenula, rostromedial tegmental nucleus, and gamma-aminobutyric acidergic ventral tegmental area neurons and adaptively constrain reward seeking.
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Affiliation(s)
- Jessica Tooley
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lauren Marconi
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jason Bondoc Alipio
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bridget Matikainen-Ankney
- Eating and Addiction Section, National Institute of Digestive and Diabetes and Kidney Diseases, Bethesda, Maryland
| | - Polymnia Georgiou
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Alexxai V Kravitz
- Eating and Addiction Section, National Institute of Digestive and Diabetes and Kidney Diseases, Bethesda, Maryland
| | - Meaghan C Creed
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland.
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Dynamic Encoding of Incentive Salience in the Ventral Pallidum: Dependence on the Form of the Reward Cue. eNeuro 2018; 5:eN-NWR-0328-17. [PMID: 29740595 PMCID: PMC5938716 DOI: 10.1523/eneuro.0328-17.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/26/2018] [Accepted: 04/20/2018] [Indexed: 12/03/2022] Open
Abstract
Some rats are especially prone to attribute incentive salience to a cue (conditioned stimulus, CS) paired with food reward (sign-trackers, STs), but the extent they do so varies as a function of the form of the CS. Other rats respond primarily to the predictive value of a cue (goal-trackers, GTs), regardless of its form. Sign-tracking is associated with greater cue-induced activation of mesolimbic structures than goal-tracking; however, it is unclear how the form of the CS itself influences activity in neural systems involved in incentive salience attribution. Thus, our goal was to determine how different cue modalities affect neural activity in the ventral pallidum (VP), which is known to encode incentive salience attribution, as rats performed a two-CS Pavlovian conditioned approach task in which both a lever-CS and a tone-CS predicted identical food reward. The lever-CS elicited sign-tracking in some rats (STs) and goal-tracking in others (GTs), whereas the tone-CS elicited only goal-tracking in all rats. The lever-CS elicited robust changes in neural activity (sustained tonic increases or decreases in firing) throughout the VP in STs, relative to GTs. These changes were not seen when STs were exposed to the tone-CS, and in GTs there were no differences in firing between the lever-CS and tone-CS. We conclude that neural activity throughout the VP encodes incentive signals and is especially responsive when a cue is of a form that promotes the attribution of incentive salience to it, especially in predisposed individuals.
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Zhu C, Yao Y, Xiong Y, Cheng M, Chen J, Zhao R, Liao F, Shi R, Song S. Somatostatin Neurons in the Basal Forebrain Promote High-Calorie Food Intake. Cell Rep 2018; 20:112-123. [PMID: 28683305 DOI: 10.1016/j.celrep.2017.06.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 04/24/2017] [Accepted: 05/29/2017] [Indexed: 11/18/2022] Open
Abstract
Obesity has become a global issue, and the overconsumption of food is thought to be a major contributor. However, the regulatory neural circuits that regulate palatable food consumption remain unclear. Here, we report that somatostatin (SOM) neurons and GABAergic (VGAT) neurons in the basal forebrain (BF) play specific roles in regulating feeding. Optogenetic stimulation of BF SOM neurons increased fat and sucrose intake within minutes and promoted anxiety-like behaviors. Furthermore, optogenetic stimulation of projections from BF SOM neurons to the lateral hypothalamic area (LHA) selectively resulted in fat intake. In addition, activation of BF VGAT neurons rapidly induced general food intake and gnawing behaviors. Whole-brain mapping of inputs and outputs showed that BF SOM neurons form bidirectional connections with several brain areas important in feeding and regulation of emotion. Collectively, these results suggest that BF SOM neurons play a selective role in hedonic feeding.
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Affiliation(s)
- Chen Zhu
- School of Life Science, Tsinghua University, Beijing 10084, China
| | - Yun Yao
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Yan Xiong
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Mingxiu Cheng
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Jing Chen
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Rui Zhao
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Fangzhou Liao
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China
| | - Runsheng Shi
- School of Life Science, Tsinghua University, Beijing 10084, China
| | - Sen Song
- Department of Biomedical Engineering, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing 10084, China.
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Richard JM, Stout N, Acs D, Janak PH. Ventral pallidal encoding of reward-seeking behavior depends on the underlying associative structure. eLife 2018; 7:33107. [PMID: 29565248 PMCID: PMC5864276 DOI: 10.7554/elife.33107] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/21/2018] [Indexed: 12/22/2022] Open
Abstract
Despite its being historically conceptualized as a motor expression site, emerging evidence suggests the ventral pallidum (VP) plays a more active role in integrating information to generate motivation. Here, we investigated whether rat VP cue responses would encode and contribute similarly to the vigor of reward-seeking behaviors trained under Pavlovian versus instrumental contingencies, when these behavioral responses consist of superficially similar locomotor response patterns but may reflect distinct underlying decision-making processes. We find that cue-elicited activity in many VP neurons predicts the latency of instrumental reward seeking, but not of Pavlovian response latency. Further, disruption of VP signaling increases the latency of instrumental but not Pavlovian reward seeking. This suggests that VP encoding of and contributions to response vigor are specific to the ability of incentive cues to invigorate reward-seeking behaviors upon which reward delivery is contingent. Sounds or other cues associated with receiving a reward can have a powerful effect on an individual’s behavior or emotions. For example, the sound of an ice cream truck might cause salivation and motivate an individual to stand in a long line. Cues may prompt specific actions necessary to receive a reward, for example, approaching the ice cream truck and paying to get an ice cream. This is called instrumental conditioning. Some cues predict reward delivery, without requiring a specific action. This is called Pavlovian conditioning. Pavlovian cues can still prompt actions, such as approaching the truck, even though the action is not required. But exactly what happens in the brain to generate these actions during the two types of learning, is unclear. Learning more about these reward-driven brain mechanisms might help scientists to develop better treatments for people with addiction or other conditions that involve compulsive reward-seeking behavior. Currently, scientists do not know enough about how the brain triggers this kind of behavior or how these processes lead to relapse in individuals who have been abstinent. Basic studies on the brain mechanisms that trigger reward-seeking behavior are needed. Now, Richard et al. show that a greater activity in neurons, or brain cells, in a part of the brain called the ventral pallidum predicts a faster response to a reward cue. In the experiments, some rats were trained to approach a certain location when they heard a particular sound in order to receive sugar water, a form of instrumental conditioning. Another group of rats underwent Pavlovian training and learned to expect sugar water every time they heard sound even if they did nothing. Both groups learned to approach the sugar water location when they heard the cue, despite the different training requirements. Richard et al. measured the activity of neurons in the ventral pallidum when the rats in the two groups heard the reward-associated sound. The experiments showed that the amount of activity in the brain cells in this area predicted whether a rat would approach the sugar-water delivery area and how quickly they would approach the reward after hearing the cue. The predictions were most reliable for rats that had to do something to get the sugar water. When Richard et al. reduced the activity in these cells they found the rats took longer to approach the reward source, but only when this action was required to receive sugar water. The experiments show that the ventral pallidum may provide the motivation to undertake reward-seeking behavior.
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Affiliation(s)
- Jocelyn M Richard
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, United States
| | - Nakura Stout
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, United States
| | - Deanna Acs
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, United States
| | - Patricia H Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, United States.,Solomon H Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, United States.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, United States
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44
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Opponent control of behavioral reinforcement by inhibitory and excitatory projections from the ventral pallidum. Nat Commun 2018; 9:849. [PMID: 29487284 PMCID: PMC5829073 DOI: 10.1038/s41467-018-03125-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 01/19/2018] [Indexed: 01/07/2023] Open
Abstract
The ventral pallidum (VP) lies at the interface between sensory, motor, and cognitive processing-with a particular role in mounting behavioral responses to rewards. Though the VP is predominantly GABAergic, glutamate neurons were recently identified, though their relative abundances and respective roles are unknown. Here, we show that VP glutamate neurons are concentrated in the rostral ventromedial VP and project to qualitatively similar targets as do VP GABA neurons. At the functional level, we used optogenetics to show that activity in VP GABA neurons can drive positive reinforcement, particularly through projections to the ventral tegmental area (VTA). On the other hand, activation of VP glutamate neurons leads to behavioral avoidance, particularly through projections to the lateral habenula. These findings highlight cell-type and projection-target specific roles for VP neurons in behavioral reinforcement, dysregulation of which could contribute to the emergence of negative symptoms associated with drug addiction and other neuropsychiatric disease.
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45
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Abstract
Due to the biological importance of sodium and its relative scarcity within many natural environments, 'salt appetite' has evolved whereby dietary salt is highly sought after and palatable when tasted. In addition to peripheral responses, salt depletion is detected within the brain via circumventricular organs and 11β-hydroxysteroid dehydrogenase type 2 (HSD2) neurons to increase salt appetite. Salt appetite is comprised of two main components. One component is the incentive salience or motivation for salt (i.e. how much salt is 'wanted'). Incentive salience is dynamic and largely depends on internal homeostatic conditions in combination with the detection of relevant cues. It involves the mesolimbic system and structures such as the central amygdala, and opioid signalling within these regions can increase salt intake in rodents. A second key feature is the hedonic palatability of salt (i.e. how much it is 'liked') when it is tasted. After detection on the tongue, gustatory information passes through the brainstem nucleus of the solitary tract and thalamus, before being consciously detected within the gustatory cerebral cortex. The positive or negative hedonic value of this stimulus is also dynamic, and is encoded by a network including the nucleus accumbens, ventral pallidum, and lateral parabrachial nucleus. Opioid signalling within these areas can alter salt intake, and 'liking'. The overconsumption of dietary salt likely contributes to hypertension and associated diseases, and hence further characterising the role played by opioid signalling has important implications for human health.
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Affiliation(s)
- Craig M Smith
- Faculty of Health, The School of Medicine, Deakin University, Geelong, VIC, 3220, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia. .,The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3052, Australia.
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46
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Chang SE, Smedley EB, Stansfield KJ, Stott JJ, Smith KS. Optogenetic Inhibition of Ventral Pallidum Neurons Impairs Context-Driven Salt Seeking. J Neurosci 2017; 37:5670-5680. [PMID: 28495976 PMCID: PMC5469304 DOI: 10.1523/jneurosci.2968-16.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 04/28/2017] [Accepted: 05/02/2017] [Indexed: 01/10/2023] Open
Abstract
Salt appetite, in which animals can immediately seek out salt when under a novel state of sodium deprivation, is a classic example of how homeostatic systems interface with learned associations to produce an on-the-fly updating of motivated behavior. Neural activity in the ventral pallidum (VP) has been shown to encode changes in the value of salt under such conditions, both the value of salt itself (Tindell et al., 2006) and the motivational value of its predictive cues (Tindell et al., 2009; Robinson and Berridge, 2013). However, it is not known whether the VP is necessary for salt appetite in terms of seeking out salt or consuming salt following sodium depletion. Here, we used a conditioned place-preference procedure to investigate the effects of optogenetically inhibiting the VP on context-driven salt seeking and the consumption of salt following deprivation. Male rats learned to associate one context with sucrose and another context with less-desirable salt. Following sodium depletion, and in the absence of either sucrose or salt, we found that inhibiting the VP selectively reduced the elevation in time spent in the salt-paired context. VP inhibition had minimal effects on the consumption of salt once it was made available. To our knowledge, this is the first evidence that the VP or any brain region is necessary for the ability to use contextual cues to guide salt seeking. These results highlight a dissociation between deficit-driven reward seeking and reward consumption to replenish those deficits, with the former process being particularly sensitive to on-line VP activity.SIGNIFICANCE STATEMENT Salt appetite, in which rats will immediately seek out a once-undesirable concentrated salt solution after being depleted of bodily sodium despite never having tasted salt as a positive reward, is a phenomenon showing how animals can update their motivational goals without any new learning or conditioning. This salt-seeking behavior is also observed when the animal is presented with salt-paired cues. The neural circuitry necessary for context-driven salt-seeking behavior is unknown. We used a novel conditioned place preference procedure to show that optogenetic inhibition of the ventral pallidum (VP), a region known for processing reward, impairs context-driven salt seeking and has minimal effects on the consumption of salt itself following sodium depletion. These results highlight the importance of the VP in context-driven reward-seeking behavior.
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Affiliation(s)
- Stephen E Chang
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, and
| | - Elizabeth B Smedley
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, and
| | - Katherine J Stansfield
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309
| | - Jeffrey J Stott
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, and
| | - Kyle S Smith
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, and
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47
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Sennwald V, Pool E, Sander D. Considering the Influence of the Pavlovian System on Behavior: Appraisal and Value Representation. PSYCHOLOGICAL INQUIRY 2017. [DOI: 10.1080/1047840x.2017.1259951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Vanessa Sennwald
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Laboratory for the Study of Emotion Elicitation and Expression, Department of Psychology, University of Geneva, Geneva, Switzerland
| | - Eva Pool
- Human Reward and Decision Making Laboratory, Humanities and Social Sciences, California Institute of Technology, Pasadena, California
| | - David Sander
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Laboratory for the Study of Emotion Elicitation and Expression, Department of Psychology, University of Geneva, Geneva, Switzerland
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48
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Inui T, Shimura T. Activation of mu-opioid receptors in the ventral pallidum decreases the negative hedonic evaluation of a conditioned aversive taste in rats. Behav Brain Res 2016; 320:391-399. [PMID: 27825896 DOI: 10.1016/j.bbr.2016.10.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 10/18/2016] [Accepted: 10/21/2016] [Indexed: 12/21/2022]
Abstract
Conditioned taste aversion (CTA) causes a shift in the hedonic evaluation of a conditioned stimulus (CS) from positive to negative, and reduces the CS intake. Mu-opioid receptors (MORs) in the ventral pallidum (VP) are known to be involved in the hedonic evaluation of positive rewarding stimuli; however, their involvement in evaluation of a negative aversive stimulus is still unclear. To explore the neural mechanisms of the negative hedonic evaluation of the CS in CTA, we examined the effects of the activation of VP MORs on the behavioral responses of rats to a CS. Rats implanted with guide cannulae into the bilateral VP received a pairing of 5mM saccharin solution as a CS with an intraperitoneal injection of 0.15M lithium chloride as an unconditioned stimulus. On the test day, after microinjections of MOR agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) into the VP, we observed the behavioral responses to the intraorally infused CS solution. The DAMGO injections caused a larger number of ingestive taste reactivity responses to the CS solution. We also measured the consumption of the CS solution in a separate group of rats, using a single-bottle test. The DAMGO injected rats drank a higher volume of the CS solution than the saline injected rats. These results indicate that the activation of MORs in the VP results in the attenuation of aversion to the CS solution, thereby inducing the larger CS intake. Therefore, it is likely that VP MORs are involved in not only positive but also negative hedonic evaluation.
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MESH Headings
- Adjuvants, Immunologic/pharmacology
- Analgesics, Opioid/pharmacology
- Animals
- Avoidance Learning/drug effects
- Conditioning, Classical/drug effects
- Conditioning, Classical/physiology
- Conditioning, Psychological/drug effects
- Drinking/drug effects
- Drug Delivery Systems
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Globus Pallidus/drug effects
- Globus Pallidus/metabolism
- Lithium Chloride/pharmacology
- Male
- Microinjections
- Rats
- Rats, Wistar
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Saccharin/administration & dosage
- Taste/drug effects
- Taste/physiology
- Taste Perception/drug effects
- Taste Perception/physiology
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Affiliation(s)
- Tadashi Inui
- Division of Behavioral Physiology, Department of Behavioral Sciences, Graduate School of Human Sciences, Osaka University, Suita, Osaka 565-0871 Japan.
| | - Tsuyoshi Shimura
- Division of Behavioral Physiology, Department of Behavioral Sciences, Graduate School of Human Sciences, Osaka University, Suita, Osaka 565-0871 Japan
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49
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Singh‐Bains MK, Waldvogel HJ, Faull RLM. The role of the human globus pallidus in Huntington's disease. Brain Pathol 2016; 26:741-751. [PMID: 27529459 PMCID: PMC8029019 DOI: 10.1111/bpa.12429] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/01/2016] [Indexed: 11/27/2022] Open
Abstract
Huntington's disease (HD) is characterized by pronounced pathology of the basal ganglia, with numerous studies documenting the pattern of striatal neurodegeneration in the human brain. However, a principle target of striatal outflow, the globus pallidus (GP), has received limited attention in comparison, despite being a core component of the basal ganglia. The external segment (GPe) is a major output of the dorsal striatum, connecting widely to other basal ganglia nuclei via the indirect motor pathway. The internal segment (GPi) is a final output station of both the direct and indirect motor pathways of the basal ganglia. The ventral pallidum (VP), in contrast, is a primary output of the limbic ventral striatum. Currently, there is a lack of consensus in the literature regarding the extent of GPe and GPi neurodegeneration in HD, with a conflict between pallidal neurons being preserved, and pallidal neurons being lost. In addition, no current evidence considers the fate of the VP in HD, despite it being a key structure involved in reward and motivation. Understanding the involvement of these structures in HD will help to determine their involvement in basal ganglia pathway dysfunction in the disease. A clear understanding of the impact of striatal projection loss on the main neurons that receive striatal input, the pallidal neurons, will aid in the understanding of disease pathogenesis. In addition, a clearer picture of pallidal involvement in HD may contribute to providing a morphological basis to the considerable variability in the types of motor, behavioral, and cognitive symptoms in HD. This review aims to highlight the importance of the globus pallidus, a critical component of the cortical-basal ganglia circuits, and its role in the pathogenesis of HD. This review also summarizes the current literature relating to human studies of the globus pallidus in HD.
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Affiliation(s)
- Malvindar K. Singh‐Bains
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
| | - Henry J. Waldvogel
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
| | - Richard L. M. Faull
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
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50
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Royet JP, Meunier D, Torquet N, Mouly AM, Jiang T. The Neural Bases of Disgust for Cheese: An fMRI Study. Front Hum Neurosci 2016; 10:511. [PMID: 27799903 PMCID: PMC5065955 DOI: 10.3389/fnhum.2016.00511] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/27/2016] [Indexed: 01/01/2023] Open
Abstract
The study of food aversion in humans by the induction of illness is ethically unthinkable, and it is difficult to propose a type of food that is disgusting for everybody. However, although cheese is considered edible by most people, it can also be perceived as particularly disgusting to some individuals. As such, the perception of cheese constitutes a good model to study the cerebral processes of food disgust and aversion. In this study, we show that a higher percentage of people are disgusted by cheese than by other types of food. Functional magnetic resonance imaging then reveals that the internal and external globus pallidus and the substantia nigra belonging to the basal ganglia are more activated in participants who dislike or diswant to eat cheese (Anti) than in other participants who like to eat cheese, as revealed following stimulation with cheese odors and pictures. We suggest that the aforementioned basal ganglia structures commonly involved in reward are also involved in the aversive motivated behaviors. Our results further show that the ventral pallidum, a core structure of the reward circuit, is deactivated in Anti subjects stimulated by cheese in the wanting task, highlighting the suppression of motivation-related activation in subjects disgusted by cheese.
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Affiliation(s)
- Jean-Pierre Royet
- Olfaction: From Coding to Memory Team, Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - Université de Lyon 1 Lyon, France
| | - David Meunier
- Olfaction: From Coding to Memory Team, Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - Université de Lyon 1 Lyon, France
| | - Nicolas Torquet
- Sorbonne Universités, Université Pierre et Marie Curie, Institut de Biologie Paris Seine, UM 119, CNRS, UMR 8246, Neuroscience Paris Seine Paris, France
| | - Anne-Marie Mouly
- Olfaction: From Coding to Memory Team, Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - Université de Lyon 1 Lyon, France
| | - Tao Jiang
- Olfaction: From Coding to Memory Team, Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - Université de Lyon 1 Lyon, France
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