1
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Thibeault KC, Leonard MZ, Kondev V, Emerson SD, Bethi R, Lopez AJ, Sens JP, Nabit BP, Elam HB, Winder DG, Patel S, Kiraly DD, Grueter BA, Calipari ES. A Cocaine-Activated Ensemble Exerts Increased Control Over Behavior While Decreasing in Size. Biol Psychiatry 2024:S0006-3223(24)01388-X. [PMID: 38901723 DOI: 10.1016/j.biopsych.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Substance use disorder is characterized by long-lasting changes in reward-related brain regions, such as the nucleus accumbens. Previous work has shown that cocaine exposure induces plasticity in broad, genetically defined cell types in the nucleus accumbens; however, in response to a stimulus, only a small percentage of neurons are transcriptionally active-termed an ensemble. Here, we identify an Arc-expressing neuronal ensemble that has a unique trajectory of recruitment and causally controls drug self-administration after repeated, but not acute, cocaine exposure. METHODS Using Arc-CreERT2 transgenic mice, we expressed transgenes in Arc+ ensembles activated by cocaine exposure (either acute [1 × 10 mg/kg intraperitoneally] or repeated [10 × 10 mg/kg intraperitoneally]). Using genetic, optical, and physiological recording and manipulation strategies, we assessed the contribution of these ensembles to behaviors associated with substance use disorder. RESULTS Repeated cocaine exposure reduced the size of the ensemble while simultaneously increasing its control over behavior. Neurons within the repeated cocaine ensemble were hyperexcitable, and their optogenetic excitation was sufficient for reinforcement. Finally, lesioning the repeated cocaine, but not the acute cocaine, ensemble blunted cocaine self-administration. Thus, repeated cocaine exposure reduced the size of the ensemble while simultaneously increasing its contributions to drug reinforcement. CONCLUSIONS We showed that repeated, but not acute, cocaine exposure induced a physiologically distinct ensemble characterized by the expression of the immediate early gene Arc, which was uniquely capable of modulating reinforcement behavior.
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Affiliation(s)
- Kimberly C Thibeault
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee
| | - Michael Z Leonard
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Veronika Kondev
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee
| | - Soren D Emerson
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee
| | - Rishik Bethi
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee
| | - Alberto J Lopez
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Jonathon P Sens
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Brett P Nabit
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Hannah B Elam
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Danny G Winder
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt JF Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Sachin Patel
- Department of Psychiatry, Northwestern University, Chicago, Illinois
| | - Drew D Kiraly
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Brad A Grueter
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee; Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Erin S Calipari
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt JF Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee.
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2
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Rajebhosale P, Ananth MR, Kim R, Crouse R, Jiang L, López-Hernández G, Zhong C, Arty C, Wang S, Jone A, Desai NS, Li Y, Picciotto MR, Role LW, Talmage DA. Functionally refined encoding of threat memory by distinct populations of basal forebrain cholinergic projection neurons. eLife 2024; 13:e86581. [PMID: 38363713 DOI: 10.7554/elife.86581] [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: 02/01/2023] [Accepted: 02/14/2024] [Indexed: 02/18/2024] Open
Abstract
Neurons of the basal forebrain nucleus basalis and posterior substantia innominata (NBM/SIp) comprise the major source of cholinergic input to the basolateral amygdala (BLA). Using a genetically encoded acetylcholine (ACh) sensor in mice, we demonstrate that BLA-projecting cholinergic neurons can 'learn' the association between a naive tone and a foot shock (training) and release ACh in the BLA in response to the conditioned tone 24 hr later (recall). In the NBM/SIp cholinergic neurons express the immediate early gene, Fos following both training and memory recall. Cholinergic neurons that express Fos following memory recall display increased intrinsic excitability. Chemogenetic silencing of these learning-activated cholinergic neurons prevents expression of the defensive behavior to the tone. In contrast, we show that NBM/SIp cholinergic neurons are not activated by an innately threatening stimulus (predator odor). Instead, VP/SIa cholinergic neurons are activated and contribute to defensive behaviors in response to predator odor, an innately threatening stimulus. Taken together, we find that distinct populations of cholinergic neurons are recruited to signal distinct aversive stimuli, demonstrating functionally refined organization of specific types of memory within the cholinergic basal forebrain of mice.
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Affiliation(s)
| | - Mala R Ananth
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Ronald Kim
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Richard Crouse
- Yale Interdepartmental Neuroscience Program, Yale University, New Haven, United States
| | - Li Jiang
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | | | - Chongbo Zhong
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | | | - Shaohua Wang
- National Institute of Environmental Health Sciences, Durham, United States
| | - Alice Jone
- Program in Neuroscience, Stony Brook University, Stony Brook, United States
| | - Niraj S Desai
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Marina R Picciotto
- Yale Interdepartmental Neuroscience Program, Yale University, New Haven, United States
- Department of Psychiatry, Yale University, New Haven, United States
| | - Lorna W Role
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - David A Talmage
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
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3
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Salery M, Godino A, Xu YQ, Fullard JF, Durand-de Cuttoli R, LaBanca AR, Holt LM, Russo SJ, Roussos P, Nestler EJ. Transcriptional correlates of cocaine-associated learning in striatal ARC ensembles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571585. [PMID: 38168167 PMCID: PMC10760161 DOI: 10.1101/2023.12.13.571585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Learned associations between the rewarding effects of drugs and the context in which they are experienced underlie context-induced relapse. Previous work demonstrates the importance of sparse neuronal populations - called neuronal ensembles - in associative learning and cocaine seeking, but it remains unknown whether the encoding vs. retrieval of cocaine-associated memories involves similar or distinct mechanisms of ensemble activation and reactivation in nucleus accumbens (NAc). We use ArcCreER T2 mice to establish that mostly distinct NAc ensembles are recruited by initial vs. repeated exposures to cocaine, which are then differentially reactivated and exert distinct effects during cocaine-related memory retrieval. Single-nuclei RNA-sequencing of these ensembles demonstrates predominant recruitment of D1 medium spiny neurons and identifies transcriptional properties that are selective to cocaine-recruited NAc neurons and could explain distinct excitability features. These findings fundamentally advance our understanding of how cocaine drives pathological memory formation during repeated exposures.
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4
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Liu X, Wang F, Le Q, Ma L. Cellular and molecular basis of drug addiction: The role of neuronal ensembles in addiction. Curr Opin Neurobiol 2023; 83:102813. [PMID: 37972536 DOI: 10.1016/j.conb.2023.102813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/19/2023]
Abstract
Addiction has been conceptualized as a disease of learning and memory. Learned associations between environmental cues and unconditioned rewards induced by drug administration, which play a critical role in addiction, have been shown to be encoded in sparsely distributed populations of neurons called neuronal ensembles. This review aims to highlight how synaptic remodeling and alterations in signaling pathways that occur specifically in neuronal ensembles contribute to the pathogenesis of addiction. Furthermore, a causal link between transcriptional and epigenetic modifications in neuronal ensembles and the development of the addictive state is proposed. Translational studies of molecular and cellular changes in neuronal ensembles that contribute to drug-seeking behavior, will allow the identification of molecular and circuit targets and interventions for substance use disorders.
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Affiliation(s)
- Xing Liu
- School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Research Unit of Addiction Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai, China
| | - Feifei Wang
- School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Research Unit of Addiction Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai, China.
| | - Qiumin Le
- School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Research Unit of Addiction Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai, China
| | - Lan Ma
- School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Research Unit of Addiction Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai, China
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5
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Xie X, Chen R, Wang X, Smith L, Wang J. Activity-dependent labeling and manipulation of fentanyl-recruited striatal ensembles using ArcTRAP approach. STAR Protoc 2023; 4:102369. [PMID: 37354458 PMCID: PMC10320278 DOI: 10.1016/j.xpro.2023.102369] [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: 03/13/2023] [Revised: 04/27/2023] [Accepted: 05/17/2023] [Indexed: 06/26/2023] Open
Abstract
Understanding the memory substrates underlying substance abuse requires the permanent tagging and manipulation of drug-recruited neural ensembles. Here, we present a protocol for activity-dependent labeling and chemogenetic manipulation of fentanyl-activated striatal ensembles using the ArcTRAP approach. We outline the necessary steps to breed ArcTRAP mice, prepare drugs and reagents, conduct behavioral training, and perform tagging and manipulation. This approach can be adapted to investigate drug-recruited ensembles in other brain regions, providing a versatile tool for exploring the neural mechanisms underlying addiction. For complete details on the use and execution of this protocol, please refer to Wang et al.1.
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Affiliation(s)
- Xueyi Xie
- Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
| | - Ruifeng Chen
- Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Xuehua Wang
- Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Laura Smith
- Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Jun Wang
- Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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6
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Savell KE, Hope BT. Chronic Cocaine-Induced ΔFOSB: Long-Lasting and Far-Reaching. Biol Psychiatry 2023; 94:362-364. [PMID: 37558312 DOI: 10.1016/j.biopsych.2023.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 08/11/2023]
Affiliation(s)
- Katherine E Savell
- Neuronal Ensembles in Addiction Section, Behavioral Neuroscience Research Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | - Bruce T Hope
- Neuronal Ensembles in Addiction Section, Behavioral Neuroscience Research Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland.
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7
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Stefaniuk M, Pawłowska M, Barański M, Nowicka K, Zieliński Z, Bijoch Ł, Legutko D, Majka P, Bednarek S, Jermakow N, Wójcik D, Kaczmarek L. Global brain c-Fos profiling reveals major functional brain networks rearrangements after alcohol reexposure. Neurobiol Dis 2023; 178:106006. [PMID: 36682503 DOI: 10.1016/j.nbd.2023.106006] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Many fundamental questions on alcohol use disorder (AUD) are frequently difficult to address by examining a single brain structure, but should be viewed from the whole brain perspective. c-Fos is a marker of neuronal activation. Global brain c-Fos profiling in rodents represents a promising platform to study brain functional networks rearrangements in AUD. We used a mouse model of alcohol drinking in IntelliCage. We trained mice to voluntarily drink alcohol, next subjected them to withdrawal and alcohol reexposure. We have developed a dedicated image computational workflow to identify c-Fos-positive cells in three-dimensional images obtained after whole-brain optical clearing and imaging in the light-sheet microscope. We provide a complete list of 169 brain structures with annotated c-Fos expression. We analyzed functional networks, brain modularity and engram index. Brain c-Fos levels in animals reexposed to alcohol were different from both control and binge drinking animals. Structures involved in reward processing, decision making and characteristic for addictive behaviors, such as precommissural nucleus, nucleus Raphe, parts of colliculus and tecta stood out particularly. Alcohol reexposure leads to a massive change of brain modularity including a formation of numerous smaller functional modules grouping structures involved in addiction development. Binge drinking can lead to substantial functional remodeling in the brain. We provide a list of structures that can be used as a target in pharmacotherapy but also point to the networks and modules that can hold therapeutic potential demonstrated by a clinical trial in patients.
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Affiliation(s)
- Marzena Stefaniuk
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland.
| | - Monika Pawłowska
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland; Institute of Experimental Physics, Section of Optics, Warsaw University, Warsaw, Poland
| | - Marcin Barański
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland
| | - Klaudia Nowicka
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland
| | | | - Łukasz Bijoch
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland; Laboratory of Neuronal Plasticity, Nencki Institute, BRAINCITY, Warsaw, Poland
| | - Diana Legutko
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland
| | - Piotr Majka
- Laboratory of Neuroinformatics, Nencki Institute, Warsaw, Poland
| | - Sylwia Bednarek
- Laboratory of Neuroinformatics, Nencki Institute, Warsaw, Poland
| | - Natalia Jermakow
- Laboratory of Neuroinformatics, Nencki Institute, Warsaw, Poland
| | - Daniel Wójcik
- Laboratory of Neuroinformatics, Nencki Institute, Warsaw, Poland
| | - Leszek Kaczmarek
- Laboratory of Neurobiology, Nencki Institute, BRAINCITY, Warsaw, Poland
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8
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Kruyer A, Kalivas PW, Scofield MD. Astrocyte regulation of synaptic signaling in psychiatric disorders. Neuropsychopharmacology 2023; 48:21-36. [PMID: 35577914 PMCID: PMC9700696 DOI: 10.1038/s41386-022-01338-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/27/2022] [Accepted: 05/01/2022] [Indexed: 02/07/2023]
Abstract
Over the last 15 years, the field of neuroscience has evolved toward recognizing the critical role of astroglia in shaping neuronal synaptic activity and along with the pre- and postsynapse is now considered an equal partner in tripartite synaptic transmission and plasticity. The relative youth of this recognition and a corresponding deficit in reagents and technologies for quantifying and manipulating astroglia relative to neurons continues to hamper advances in understanding tripartite synaptic physiology. Nonetheless, substantial advances have been made and are reviewed herein. We review the role of astroglia in synaptic function and regulation of behavior with an eye on how tripartite synapses figure into brain pathologies underlying behavioral impairments in psychiatric disorders, both from the perspective of measures in postmortem human brains and more subtle influences on tripartite synaptic regulation of behavior in animal models of psychiatric symptoms. Our goal is to provide the reader a well-referenced state-of-the-art understanding of current knowledge and predict what we may discover with deeper investigation of tripartite synapses using reagents and technologies not yet available.
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Affiliation(s)
- Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA.
| | - Michael D Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Department of Anesthesia & Perioperative Medicine, Medical University of South Carolina, Charleston, SC, USA.
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9
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Cincotta C, Ruesch E, Senne R, Ramirez S. Hippocampal fear engrams modulate ethanol-induced maladaptive contextual generalization in mice. Hippocampus 2022; 32:707-715. [PMID: 35950345 DOI: 10.1002/hipo.23463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 06/27/2022] [Accepted: 07/16/2022] [Indexed: 11/09/2022]
Abstract
The compounding symptomatology of alcohol use disorder (AUD) and co-occurring mental health disorders gives rise to interactions of maladaptive neurobiological processes, the etiology of which are elusive. Here, we devised an optogenetic strategy aimed at rescuing maladaptive fear processing in male c57BL/6 mice that underwent a chronic ethanol administration and forced abstinence paradigm. In the first experiment, we confirmed that fear acquisition and maladaptive contextual generalization was potentiated in ethanol-exposed mice during fear conditioning and exposure to a novel environment, respectively. In the second experiment, using an activity-dependent tet-tag system, we labeled the neural ensemble selectively activated by contextual fear conditioning in the dorsal hippocampus with an inhibitory opsin to attenuate behavioral dysfunctions resulting from ethanol exposure. We found that acute optogenetic perturbations during exposure to a novel environment suppressed maladaptive generalization in ethanol-exposed mice. These results provide further evidence for a crucial link between ethanol exposure and impaired fear memory processing by providing cellular and behavioral insights into the neural circuitry underlying AUD and maladaptive fear processing.
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Affiliation(s)
- Christine Cincotta
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Evan Ruesch
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Ryan Senne
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
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10
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Ortega-de San Luis C, Ryan TJ. Understanding the physical basis of memory: Molecular mechanisms of the engram. J Biol Chem 2022; 298:101866. [PMID: 35346687 PMCID: PMC9065729 DOI: 10.1016/j.jbc.2022.101866] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 12/18/2022] Open
Abstract
Memory, defined as the storage and use of learned information in the brain, is necessary to modulate behavior and critical for animals to adapt to their environments and survive. Despite being a cornerstone of brain function, questions surrounding the molecular and cellular mechanisms of how information is encoded, stored, and recalled remain largely unanswered. One widely held theory is that an engram is formed by a group of neurons that are active during learning, which undergoes biochemical and physical changes to store information in a stable state, and that are later reactivated during recall of the memory. In the past decade, the development of engram labeling methodologies has proven useful to investigate the biology of memory at the molecular and cellular levels. Engram technology allows the study of individual memories associated with particular experiences and their evolution over time, with enough experimental resolution to discriminate between different memory processes: learning (encoding), consolidation (the passage from short-term to long-term memories), and storage (the maintenance of memory in the brain). Here, we review the current understanding of memory formation at a molecular and cellular level by focusing on insights provided using engram technology.
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Affiliation(s)
- Clara Ortega-de San Luis
- School of Biochemistry and Immunology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.
| | - Tomás J Ryan
- School of Biochemistry and Immunology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland; Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada.
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11
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Jessen K, Slaker Bennett ML, Liu S, Olsen CM. Comparison of prefrontal cortex sucrose seeking ensembles engaged in multiple seeking sessions: Context is key. J Neurosci Res 2022; 100:1008-1029. [PMID: 35137974 PMCID: PMC8940716 DOI: 10.1002/jnr.25025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/31/2021] [Accepted: 01/17/2022] [Indexed: 12/11/2022]
Abstract
Encoding of memories, including those associated with prior drug or reward, is thought to take place within distinct populations of neurons, termed ensembles. Neuronal ensembles for drug- and reward-seeking have been identified in regions of the medial prefrontal cortex, but much of our understanding of these ensembles is based on experiments that take place in a single reward-associated environment and measure ensemble encoding over short durations of time. In contrast, reward seeking behavior is evident across different reward-associated environments and persists over time. Using TetTag mice and Fos immunohistochemistry, we examined the relationship between persistent sucrose-seeking and ensemble encoding in mice that undergo seeking sessions in the same or different sucrose self-administration contexts 2 weeks apart. We found that prelimbic (PrL) and anterior cingulate cortex ensembles tagged in the first seeking session were highly sensitive to the context in which a second seeking session took place: reactivation of these ensembles was reduced in the same context but elevated in a distinct sucrose self-administration context. Correlational analyses revealed that ensemble reactivation in the PrL was proportional to the persistence of sucrose seeking behavior across sessions in differing ways in female mice. In the same context, reactivation was proportional to the persistence of non-reinforced operant responses, whereas in a distinct context, reactivation was proportional to the persistence of non-reinforced head entries into the sucrose receptacle. This study underlines the importance of the medial prefrontal cortex importance in maintaining a reward-seeking ensemble over time and identifies context-dependent changes in behavioral correlates of ensemble reactivation.
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Affiliation(s)
- Kristen Jessen
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Megan L Slaker Bennett
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Department of Neuroscience, Wisconsin Lutheran College, Milwaukee, Wisconsin, USA
| | - Shuai Liu
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christopher M Olsen
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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12
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Zinsmaier AK, Dong Y, Huang YH. Cocaine-induced projection-specific and cell type-specific adaptations in the nucleus accumbens. Mol Psychiatry 2022; 27:669-686. [PMID: 33963288 PMCID: PMC8691189 DOI: 10.1038/s41380-021-01112-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 03/29/2021] [Accepted: 04/09/2021] [Indexed: 02/03/2023]
Abstract
Cocaine craving, seeking, and relapse are mediated, in part, by cocaine-induced adaptive changes in the brain reward circuits. The nucleus accumbens (NAc) integrates and prioritizes different emotional and motivational inputs to the reward system by processing convergent glutamatergic projections from the medial prefrontal cortex, basolateral amygdala, ventral hippocampus, and other limbic and paralimbic brain regions. Medium spiny neurons (MSNs) are the principal projection neurons in the NAc, which can be divided into two major subpopulations, namely dopamine receptor D1- versus D2-expressing MSNs, with complementing roles in reward-associated behaviors. After cocaine experience, NAc MSNs exhibit complex and differential adaptations dependent on cocaine regimen, withdrawal time, cell type, location (NAc core versus shell), and related input and output projections, or any combination of these factors. Detailed characterization of these cellular adaptations has been greatly facilitated by the recent development of optogenetic/chemogenetic techniques combined with transgenic tools. In this review, we discuss such cell type- and projection-specific adaptations induced by cocaine experience. Specifically, (1) D1 and D2 NAc MSNs frequently exhibit differential adaptations in spinogenesis, glutamatergic receptor trafficking, and intrinsic membrane excitability, (2) cocaine experience differentially changes the synaptic transmission at different afferent projections onto NAc MSNs, (3) cocaine-induced NAc adaptations exhibit output specificity, e.g., being different at NAc-ventral pallidum versus NAc-ventral tegmental area synapses, and (4) the input, output, subregion, and D1/D2 cell type may together determine cocaine-induced circuit plasticity in the NAc. In light of the projection- and cell-type specificity, we also briefly discuss ensemble and circuit mechanisms contributing to cocaine craving and relapse after drug withdrawal.
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Affiliation(s)
| | - Yan Dong
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15219,Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15219
| | - Yanhua H. Huang
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15219
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13
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Vickstrom CR, Snarrenberg ST, Friedman V, Liu QS. Application of optogenetics and in vivo imaging approaches for elucidating the neurobiology of addiction. Mol Psychiatry 2022; 27:640-651. [PMID: 34145393 PMCID: PMC9190069 DOI: 10.1038/s41380-021-01181-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/26/2021] [Indexed: 02/05/2023]
Abstract
The neurobiology of addiction has been an intense topic of investigation for more than 50 years. Over this time, technological innovation in methods for studying brain function rapidly progressed, leading to increasingly sophisticated experimental approaches. To understand how specific brain regions, cell types, and circuits are affected by drugs of abuse and drive behaviors characteristic of addiction, it is necessary both to observe and manipulate neural activity in addiction-related behavioral paradigms. In pursuit of this goal, there have been several key technological advancements in in vivo imaging and neural circuit modulation in recent years, which have shed light on the cellular and circuit mechanisms of addiction. Here we discuss some of these key technologies, including circuit modulation with optogenetics, in vivo imaging with miniaturized single-photon microscopy (miniscope) and fiber photometry, and how the application of these technologies has garnered novel insights into the neurobiology of addiction.
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14
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Nall RW, Heinsbroek JA, Nentwig TB, Kalivas PW, Bobadilla AC. Circuit selectivity in drug versus natural reward seeking behaviors. J Neurochem 2021; 157:1450-1472. [PMID: 33420731 PMCID: PMC8178159 DOI: 10.1111/jnc.15297] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/16/2020] [Accepted: 01/03/2021] [Indexed: 12/23/2022]
Abstract
Substance use disorder (SUD) is characterized, in part by behavior biased toward drug use and away from natural sources of reward (e.g., social interaction, food, sex). The neurobiological underpinnings of SUDs reveal distinct brain regions where neuronal activity is necessary for the manifestation of SUD-characteristic behaviors. Studies that specifically examine how these regions are involved in behaviors motivated by drug versus natural reward allow determinations of which regions are necessary for regulating seeking of both reward types, and appraisals of novel SUD therapies for off-target effects on behaviors motivated by natural reward. Here, we evaluate studies directly comparing regulatory roles for specific brain regions in drug versus natural reward. While it is clear that many regions drive behaviors motivated by all reward types, based on the literature reviewed we propose a set of interconnected regions that become necessary for behaviors motivated by drug, but not natural rewards. The circuitry is selectively necessary for drug seeking includes an Action/Reward subcircuit, comprising nucleus accumbens, ventral pallidum, and ventral tegmental area, a Prefrontal subcircuit comprising prelimbic, infralimbic, and insular cortices, a Stress subcircuit comprising the central nucleus of the amygdala and the bed nucleus of the stria terminalis, and a Diencephalon circuit including lateral hypothalamus. Evidence was mixed for nucleus accumbens shell, insular cortex, and ventral pallidum. Studies for all other brain nuclei reviewed supported a necessary role in regulating both drug and natural reward seeking. Finally, we discuss emerging strategies to further disambiguate the necessity of brain regions in drug- versus natural reward-associated behaviors.
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Affiliation(s)
- Rusty W. Nall
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Jasper A. Heinsbroek
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Todd B. Nentwig
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W. Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
- These authors share senior authorship
| | - Ana-Clara Bobadilla
- School of Pharmacy, University of Wyoming, Laramie, WY, USA
- These authors share senior authorship
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15
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Ryan TJ, Ortega-de San Luis C, Pezzoli M, Sen S. Engram cell connectivity: an evolving substrate for information storage. Curr Opin Neurobiol 2021; 67:215-225. [PMID: 33812274 DOI: 10.1016/j.conb.2021.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 01/02/2023]
Abstract
Understanding memory requires an explanation for how information can be stored in the brain in a stable state. The change in the brain that accounts for a given memory is referred to as an engram. In recent years, the term engram has been operationalized as the cells that are activated by a learning experience, undergoes plasticity, and are sufficient and necessary for memory recall. Using this framework, and a growing toolbox of related experimental techniques, engram manipulation has become a central topic in behavioral, systems, and molecular neuroscience. Recent research on the topic has provided novel insights into the mechanisms of long-term memory storage, and its overlap with instinct. We propose that memory and instinct may be embodied as isomorphic topological structures within the brain's microanatomical circuitry.
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Affiliation(s)
- Tomás J Ryan
- School of Biochemistry and Immunology and Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, D02 PN40, Ireland; Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC 3052, Australia; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario M5G 1M1, Canada.
| | - Clara Ortega-de San Luis
- School of Biochemistry and Immunology and Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Maurizio Pezzoli
- School of Biochemistry and Immunology and Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Siddhartha Sen
- Centre for Research on Adaptive Nanostructures and Nanodevices and School of Physics, Trinity College Dublin, D02 PN40, Ireland
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16
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Rao-Ruiz P, Visser E, Mitrić M, Smit AB, van den Oever MC. A Synaptic Framework for the Persistence of Memory Engrams. Front Synaptic Neurosci 2021; 13:661476. [PMID: 33841124 PMCID: PMC8024575 DOI: 10.3389/fnsyn.2021.661476] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 02/26/2021] [Indexed: 12/31/2022] Open
Abstract
The ability to store and retrieve learned information over prolonged periods of time is an essential and intriguing property of the brain. Insight into the neurobiological mechanisms that underlie memory consolidation is of utmost importance for our understanding of memory persistence and how this is affected in memory disorders. Recent evidence indicates that a given memory is encoded by sparsely distributed neurons that become highly activated during learning, so-called engram cells. Research by us and others confirms the persistent nature of cortical engram cells by showing that these neurons are required for memory expression up to at least 1 month after they were activated during learning. Strengthened synaptic connectivity between engram cells is thought to ensure reactivation of the engram cell network during retrieval. However, given the continuous integration of new information into existing neuronal circuits and the relatively rapid turnover rate of synaptic proteins, it is unclear whether a lasting learning-induced increase in synaptic connectivity is mediated by stable synapses or by continuous dynamic turnover of synapses of the engram cell network. Here, we first discuss evidence for the persistence of engram cells and memory-relevant adaptations in synaptic plasticity, and then propose models of synaptic adaptations and molecular mechanisms that may support memory persistence through the maintenance of enhanced synaptic connectivity within an engram cell network.
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Affiliation(s)
- Priyanka Rao-Ruiz
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Esther Visser
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Miodrag Mitrić
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Michel C van den Oever
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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17
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Salery M, Godino A, Nestler EJ. Drug-activated cells: From immediate early genes to neuronal ensembles in addiction. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 90:173-216. [PMID: 33706932 DOI: 10.1016/bs.apha.2020.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Beyond their rapid rewarding effects, drugs of abuse can durably alter an individual's response to their environment as illustrated by the compulsive drug seeking and risk of relapse triggered by drug-associated stimuli. The persistence of these associations even long after cessation of drug use demonstrates the enduring mark left by drugs on brain reward circuits. However, within these circuits, neuronal populations are differently affected by drug exposure and growing evidence indicates that relatively small subsets of neurons might be involved in the encoding and expression of drug-mediated associations. The identification of sparse neuronal populations recruited in response to drug exposure has benefited greatly from the study of immediate early genes (IEGs) whose induction is critical in initiating plasticity programs in recently activated neurons. In particular, the development of technologies to manipulate IEG-expressing cells has been fundamental to implicate broadly distributed neuronal ensembles coincidently activated by either drugs or drug-associated stimuli and to then causally establish their involvement in drug responses. In this review, we summarize the literature regarding IEG regulation in different learning paradigms and addiction models to highlight their role as a marker of activity and plasticity. As the exploration of neuronal ensembles in addiction improves our understanding of drug-associated memory encoding, it also raises several questions regarding the cellular and molecular characteristics of these discrete neuronal populations as they become incorporated in drug-associated neuronal ensembles. We review recent efforts towards this goal and discuss how they will offer a more comprehensive understanding of addiction pathophysiology.
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Affiliation(s)
- Marine Salery
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Arthur Godino
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Eric J Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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18
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Bobadilla AC, Dereschewitz E, Vaccaro L, Heinsbroek JA, Scofield MD, Kalivas PW. Cocaine and sucrose rewards recruit different seeking ensembles in the nucleus accumbens core. Mol Psychiatry 2020; 25:3150-3163. [PMID: 32985600 PMCID: PMC8532193 DOI: 10.1038/s41380-020-00888-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022]
Abstract
Poorly regulated reward seeking is a central feature of substance use disorder. Recent research shows that rewarding drug-related experiences induce synchronous activation of a discrete number of neurons in the nucleus accumbens that are causally linked to reward-related contexts. Here we comprehensively characterize the specific ensemble of neurons built through experience that are linked to seeking behavior. We additionally address the question of whether or not addictive drugs usurp the neuronal networks recruited by natural rewards by evaluating cocaine- and sucrose-associated ensembles within the same mouse. We used FosCreERT2/+/Ai14 transgenic mice to tag cells activated by and potentially encoding cocaine and sucrose seeking. We tagged ~1% of neurons in the core subregion of the accumbens (NAcore) activated during cue-induced seeking for cocaine or sucrose. The majority of tagged cells in the seeking ensembles were D1-MSNs, and specifically activated during seeking, not during extinction or when mice remained in the home cage. To compare different reward-specific ensembles within the same mouse, we used a dual cocaine and sucrose self-administration protocol allowing reward-specific seeking. Using this model, we found ~70% distinction between the cells constituting the cocaine- compared to the sucrose-seeking ensemble. Establishing that cocaine recruits an ensemble of NAcore neurons largely distinct from neurons recruited into an ensemble coding for sucrose seeking suggest a finely tuned specificity of ensembles. The findings allow further exploration of the mechanisms that transform reward-based positive reinforcement into maladaptive drug seeking.
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Affiliation(s)
- Ana-Clara Bobadilla
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- School of Pharmacy, University of Wyoming, Laramie, WY, USA.
| | - Eric Dereschewitz
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Lucio Vaccaro
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Jasper A Heinsbroek
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Michael D Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
- Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
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19
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Abstract
Opioids are commonly used as analgesics for severe pain, but their addictive potential has sparked a misuse epidemic. In this issue of Neuron, Keyes et al. (2020) examine the contributions of distinct paraventricular thalamus (PVT) outputs to contextual opioid memories. They identify a PVT→NAc→LH circuit essential for recall of opioid experiences.
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Affiliation(s)
- Horia Pribiag
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Byung Kook Lim
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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20
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Cincotta C, Murawski NJ, Grella SL, McKissick O, Doucette E, Ramirez S. Chronic activation of fear engrams induces extinction-like behavior in ethanol-exposed mice. Hippocampus 2020; 31:3-10. [PMID: 32946184 DOI: 10.1002/hipo.23263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/21/2020] [Accepted: 08/30/2020] [Indexed: 01/31/2023]
Abstract
Alcohol withdrawal directly impacts the brain's stress and memory systems, which may underlie individual susceptibility to persistent drug and alcohol-seeking behaviors. Numerous studies demonstrate that forced alcohol abstinence, which may lead to withdrawal, can impair fear-related memory processes in rodents such as extinction learning; however, the underlying neural circuits mediating these impairments remain elusive. Here, we tested an optogenetic strategy aimed at mitigating fear extinction retrieval impairments in male c57BL/6 mice following exposure to alcohol (i.e., ethanol) and forced abstinence. In the first experiment, extensive behavioral extinction training in a fear-conditioned context was impaired in ethanol-exposed mice compared to controls. In the second experiment, neuronal ensembles processing a contextual fear memory in the dorsal hippocampus were tagged and optogenetically reactivated repeatedly in a distinct context in ethanol-exposed and control mice. Chronic activation of these cells resulted in a context-specific, extinction-like reduction in fear responses in both control and ethanol-exposed mice. These findings suggest that while ethanol can impair the retrieval an extinction memory, optogenetic manipulation of a fear engram is sufficient to induce an extinction-like reduction in fear responses.
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Affiliation(s)
- Christine Cincotta
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | | | - Stephanie L Grella
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Olivia McKissick
- Department of Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Emily Doucette
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
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21
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Sharma PK, Wells L, Rizzo G, Elson JL, Passchier J, Rabiner EA, Gunn RN, Dexter DT, Pienaar IS. DREADD Activation of Pedunculopontine Cholinergic Neurons Reverses Motor Deficits and Restores Striatal Dopamine Signaling in Parkinsonian Rats. Neurotherapeutics 2020; 17:1120-1141. [PMID: 31965550 PMCID: PMC7609798 DOI: 10.1007/s13311-019-00830-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The brainstem-based pedunculopontine nucleus (PPN) traditionally associates with motor function, but undergoes extensive degeneration during Parkinson's disease (PD), which correlates with axial motor deficits. PPN-deep brain stimulation (DBS) can alleviate certain symptoms, but its mechanism(s) of action remains unknown. We previously characterized rats hemi-intranigrally injected with the proteasomal inhibitor lactacystin, as an accurate preclinical model of PD. Here we used a combination of chemogenetics with positron emission tomography imaging for in vivo interrogation of discrete neural networks in this rat model of PD. Stimulation of excitatory designer receptors exclusively activated by designer drugs expressed within PPN cholinergic neurons activated residual nigrostriatal dopaminergic neurons to produce profound motor recovery, which correlated with striatal dopamine efflux as well as restored dopamine receptor 1- and dopamine receptor 2-based medium spiny neuron activity, as was ascertained with c-Fos-based immunohistochemistry and stereological cell counts. By revealing that the improved axial-related motor functions seen in PD patients receiving PPN-DBS may be due to stimulation of remaining PPN cholinergic neurons interacting with dopaminergic ones in both the substantia nigra pars compacta and the striatum, our data strongly favor the PPN cholinergic-midbrain dopaminergic connectome as mechanism for PPN-DBS's therapeutic effects. These findings have implications for refining PPN-DBS as a promising treatment modality available to PD patients.
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Affiliation(s)
- Puneet K Sharma
- Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Lisa Wells
- Invicro, Hammersmith Hospital Campus, Imperial College London, London, W12 0NN, UK
| | - Gaia Rizzo
- Invicro, Hammersmith Hospital Campus, Imperial College London, London, W12 0NN, UK
| | - Joanna L Elson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jan Passchier
- Invicro, Hammersmith Hospital Campus, Imperial College London, London, W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro, Hammersmith Hospital Campus, Imperial College London, London, W12 0NN, UK
| | - Roger N Gunn
- Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
- Invicro, Hammersmith Hospital Campus, Imperial College London, London, W12 0NN, UK
| | - David T Dexter
- Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Ilse S Pienaar
- Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK.
- School of Life Sciences, University of Sussex, Falmer, BN1 9PH, UK.
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22
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Visser E, Matos MR, van der Loo RJ, Marchant NJ, de Vries TJ, Smit AB, van den Oever MC. A persistent alcohol cue memory trace drives relapse to alcohol seeking after prolonged abstinence. SCIENCE ADVANCES 2020; 6:eaax7060. [PMID: 32494694 PMCID: PMC7202866 DOI: 10.1126/sciadv.aax7060] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 02/24/2020] [Indexed: 05/26/2023]
Abstract
Alcohol use disorder is characterized by a high risk of relapse during periods of abstinence. Relapse is often triggered by retrieval of persistent alcohol memories upon exposure to alcohol-associated environmental cues, but little is known about the neuronal circuitry that supports the long-term storage of alcohol cue associations. We found that a small ensemble of neurons in the medial prefrontal cortex (mPFC) of mice was activated during cue-paired alcohol self-administration (SA) and that selective suppression of these neurons 1 month later attenuated cue-induced relapse to alcohol seeking. Inhibition of alcohol seeking was specific to these neurons as suppression of a non-alcohol-related or sucrose SA-activated mPFC ensemble did not affect relapse behavior. Hence, the mPFC neuronal ensemble activated during cue-paired alcohol consumption functions as a lasting memory trace that mediates cue-evoked relapse long after cessation of alcohol intake, thereby providing a potential target for treatment of alcohol relapse vulnerability.
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Affiliation(s)
- Esther Visser
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
| | - Mariana R. Matos
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
| | - Rolinka J. van der Loo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
| | - Nathan J. Marchant
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam UMC, Location VUmc, 1081 HZ, Netherlands
| | - Taco J. de Vries
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam UMC, Location VUmc, 1081 HZ, Netherlands
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
| | - Michel C. van den Oever
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Netherlands
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23
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Wall NR, Neumann PA, Beier KT, Mokhtari AK, Luo L, Malenka RC. Complementary Genetic Targeting and Monosynaptic Input Mapping Reveal Recruitment and Refinement of Distributed Corticostriatal Ensembles by Cocaine. Neuron 2019; 104:916-930.e5. [PMID: 31759807 DOI: 10.1016/j.neuron.2019.10.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 09/24/2019] [Accepted: 10/24/2019] [Indexed: 10/25/2022]
Abstract
Drugs of abuse elicit powerful experiences that engage populations of neurons broadly distributed throughout the brain. To determine how synaptic connectivity is organized to enable robust communication between populations of drug-activated neurons, we developed a complementary targeting system for monosynaptic rabies virus (RV) tracing that identifies direct inputs to activated versus nonactivated neuronal populations. Analysis of over 100,000 synaptic input neurons demonstrated that cocaine-activated neurons comprise selectively connected but broadly distributed corticostriatal networks. Electrophysiological assays using optogenetics to stimulate activated versus nonactivated inputs revealed stronger synapses between coactivated cortical pyramidal neurons and neurons in the dorsal striatum (DS). Repeated cocaine exposure further enhanced the connectivity specifically between drug-activated neurons in the orbitofrontal cortex (OFC) and coactive DS neurons. Selective chemogenetic silencing of cocaine-activated OFC neurons or their terminals in the DS disrupted behavioral sensitization, demonstrating the utility of this methodology for identifying novel circuit elements that contribute to behavioral plasticity.
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Affiliation(s)
- Nicholas R Wall
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peter A Neumann
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin T Beier
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ava K Mokhtari
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Liqun Luo
- Department of Biology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert C Malenka
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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24
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The Emergence of a Stable Neuronal Ensemble from a Wider Pool of Activated Neurons in the Dorsal Medial Prefrontal Cortex during Appetitive Learning in Mice. J Neurosci 2019; 40:395-410. [PMID: 31727794 DOI: 10.1523/jneurosci.1496-19.2019] [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: 06/26/2019] [Revised: 11/04/2019] [Accepted: 11/06/2019] [Indexed: 11/21/2022] Open
Abstract
Animals selectively respond to environmental cues associated with food reward to optimize nutrient intake. Such appetitive conditioned stimulus-unconditioned stimulus (CS-US) associations are thought to be encoded in select, stable neuronal populations or neuronal ensembles, which undergo physiological modifications during appetitive conditioning. These ensembles in the medial prefrontal cortex (mPFC) control well-established, cue-evoked food seeking, but the mechanisms involved in the genesis of these ensembles are unclear. Here, we used male Fos-GFP mice that express green fluorescent protein (GFP) in recently behaviorally activated neurons, to reveal how dorsal mPFC neurons are recruited and modified to encode CS-US memory representations using an appetitive conditioning task. In the initial conditioning session, animals did not exhibit discriminated, cue-selective food seeking, but did so in later sessions indicating that a CS-US association was established. Using microprism-based in vivo 2-Photon imaging, we revealed that only a minority of neurons activated during the initial session was consistently activated throughout subsequent conditioning sessions and during cue-evoked memory recall. Notably, using ex vivo electrophysiology, we found that neurons activated following the initial session exhibited transient hyperexcitability. Chemogenetically enhancing the excitability of these neurons throughout subsequent conditioning sessions interfered with the development of reliable cue-selective food seeking, indicated by persistent, nondiscriminated performance. We demonstrate how appetitive learning consistently activates a subset of neurons to form a stable neuronal ensemble during the formation of a CS-US association. This ensemble may arise from a pool of hyperexcitable neurons activated during the initial conditioning session.SIGNIFICANCE STATEMENT Appetitive conditioning endows cues associated with food with the ability to guide food-seeking, through the formation of a food-cue association. Neuronal ensembles in the mPFC control established cue-evoked food-seeking. However, how neurons undergo physiological modifications and become part of an ensemble during conditioning remain unclear. We found that only a minority of dorsal mPFC neurons activated on the initial conditioning session became consistently activated during conditioning and memory recall. These initially activated neurons were also transiently hyperexcitable. We demonstrate the following: (1) how stable neuronal ensemble formation in the dorsal mPFC underlies appetitive conditioning; and (2) how this ensemble may arise from hyperexcitable neurons activated before the establishment of cue-evoked food seeking.
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25
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Reward Devaluation Attenuates Cue-Evoked Sucrose Seeking and Is Associated with the Elimination of Excitability Differences between Ensemble and Non-ensemble Neurons in the Nucleus Accumbens. eNeuro 2019; 6:ENEURO.0338-19.2019. [PMID: 31699890 PMCID: PMC6905639 DOI: 10.1523/eneuro.0338-19.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 11/21/2022] Open
Abstract
Animals must learn relationships between foods and the environmental cues that predict their availability for survival. Such cue–food associations are encoded in sparse sets of neurons or “neuronal ensembles” in the nucleus accumbens (NAc). For these ensemble-encoded, cue-controlled appetitive responses to remain adaptive, they must allow for their dynamic updating depending on acute changes in internal states such as physiological hunger or the perceived desirability of food. However, how these neuronal ensembles are recruited and physiologically modified following the update of such learned associations is unclear. To investigate this, we examined the effects of devaluation on ensemble plasticity at the levels of recruitment, intrinsic excitability, and synaptic physiology in sucrose-conditioned Fos-GFP mice that express green fluorescent protein (GFP) in recently activated neurons. Neuronal ensemble activation patterns and their physiology were examined using immunohistochemistry and slice electrophysiology, respectively. Reward-specific devaluation following 4 d of ad libitum sucrose consumption, but not general caloric devaluation, attenuated cue-evoked sucrose seeking. This suggests that changes in the hedonic and/or incentive value of sucrose, and not caloric need, drove this behavior. Moreover, devaluation attenuated the size of the neuronal ensemble recruited by the cue in the NAc shell. Finally, it eliminated the relative enhanced excitability of ensemble (GFP+) neurons against non-ensemble (GFP−) neurons observed under non-devalued conditions, and did not induce any ensemble-specific changes in excitatory synaptic physiology. Our findings provide new insights into neuronal ensemble mechanisms that underlie the changes in the incentive and/or hedonic impact of cues that support adaptive food seeking.
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Mews P, Walker DM, Nestler EJ. Epigenetic Priming in Drug Addiction. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2018; 83:131-139. [PMID: 30936392 PMCID: PMC6764605 DOI: 10.1101/sqb.2018.83.037663] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Drug addiction is a chronic relapsing brain disorder that is characterized by compulsive drug seeking and continued use despite negative outcomes. Current pharmacological therapies target neuronal receptors or transporters upon which drugs of abuse act initially, yet these treatments remain ineffective for most individuals and do not prevent disease relapse after abstinence. Drugs of abuse, in addition to their acute effects, cause persistent plasticity after repeated use, involving dysregulated gene expression in the brain's reward regions, which are thought to mediate the persistent behavioral abnormalities that characterize addiction. Emerging evidence implicates epigenetic priming as a key mechanism that underlies the long-lasting alterations in neuronal gene regulation, which can remain latent until triggered by re-exposure to drug-associated stimuli or the drug itself. Thus, to effectively treat drug addiction, we must identify the precise epigenetic mechanisms that establish and preserve the drug-induced pathology of the brain reward circuitry.
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Affiliation(s)
- Philipp Mews
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Deena M Walker
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Eric J Nestler
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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