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Xu Y, Lin Y, Yu M, Zhou K. The nucleus accumbens in reward and aversion processing: insights and implications. Front Behav Neurosci 2024; 18:1420028. [PMID: 39184934 PMCID: PMC11341389 DOI: 10.3389/fnbeh.2024.1420028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 07/26/2024] [Indexed: 08/27/2024] Open
Abstract
The nucleus accumbens (NAc), a central component of the brain's reward circuitry, has been implicated in a wide range of behaviors and emotional states. Emerging evidence, primarily drawing from recent rodent studies, suggests that the function of the NAc in reward and aversion processing is multifaceted. Prolonged stress or drug use induces maladaptive neuronal function in the NAc circuitry, which results in pathological conditions. This review aims to provide comprehensive and up-to-date insights on the role of the NAc in motivated behavior regulation and highlights areas that demand further in-depth analysis. It synthesizes the latest findings on how distinct NAc neuronal populations and pathways contribute to the processing of opposite valences. The review examines how a range of neuromodulators, especially monoamines, influence the NAc's control over various motivational states. Furthermore, it delves into the complex underlying mechanisms of psychiatric disorders such as addiction and depression and evaluates prospective interventions to restore NAc functionality.
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Affiliation(s)
| | | | | | - Kuikui Zhou
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, China
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2
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Hamati R, Ahrens J, Shvetz C, Holahan MR, Tuominen L. 65 years of research on dopamine's role in classical fear conditioning and extinction: A systematic review. Eur J Neurosci 2024; 59:1099-1140. [PMID: 37848184 DOI: 10.1111/ejn.16157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 10/19/2023]
Abstract
Dopamine, a catecholamine neurotransmitter, has historically been associated with the encoding of reward, whereas its role in aversion has received less attention. Here, we systematically gathered the vast evidence of the role of dopamine in the simplest forms of aversive learning: classical fear conditioning and extinction. In the past, crude methods were used to augment or inhibit dopamine to study its relationship with fear conditioning and extinction. More advanced techniques such as conditional genetic, chemogenic and optogenetic approaches now provide causal evidence for dopamine's role in these learning processes. Dopamine neurons encode conditioned stimuli during fear conditioning and extinction and convey the signal via activation of D1-4 receptor sites particularly in the amygdala, prefrontal cortex and striatum. The coordinated activation of dopamine receptors allows for the continuous formation, consolidation, retrieval and updating of fear and extinction memory in a dynamic and reciprocal manner. Based on the reviewed literature, we conclude that dopamine is crucial for the encoding of classical fear conditioning and extinction and contributes in a way that is comparable to its role in encoding reward.
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Affiliation(s)
- Rami Hamati
- Neuroscience Graduate Program, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
| | - Jessica Ahrens
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Cecelia Shvetz
- University of Ottawa Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Matthew R Holahan
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Lauri Tuominen
- University of Ottawa Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
- Department of Psychiatry, University of Ottawa, Ottawa, Ontario, Canada
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3
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Liu W, Wang W, Wang Z, Xing Y. Ventral tegmental area dopaminergic circuits participates in stress-induced chronic postsurgical pain in male mice. BMC Neurosci 2024; 25:3. [PMID: 38195391 PMCID: PMC10775611 DOI: 10.1186/s12868-023-00842-z] [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: 05/10/2023] [Accepted: 12/18/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND Chronic postsurgical pain (CPP) markedly impairs patients' quality of life. Research has shown that chronic stress may extend incisional nociception in male mice. Dopaminergic (DAergic) neurons in the ventral tegmental area (VTA) are integral to stress-related mental disorders (including major depressive disorder, anxiety disorders, and PTSD) and pain. However, the impact of chronic social defeat stress (CSDS) on mesolimbic dopamine (DA) transmission in the development of CPP is yet to be established. It remains uncertain whether the dopamine signals in the rostral anterior cingulate cortex (rACC), which regulate pain, derive from the VTA. This study aims to explore the role of VTA-rACC dopaminergic circuits in a mouse model of CPP induced by CSDS. METHODS We conducted CSDS on C57BL/6 J wild-type male mice (n = 12-16 mice/group) and DAT-cre male mice (n = 10-12 mice/group). After 10 days of CSDS, a left posterior plantar incision was made to establish a mouse model of CPP. Paw withdrawal thresholds (PWTs) were evaluated using Von-Frey fibre stimulation. The open field test (OFT) and elevated plus maze test (EPM) were used to assess pain-related negative emotions. We used immunofluorescence staining and Western Blot to analyse D1, D2, c-Fos, and TH expression. DAergic fibre projections in the VTA-rACC neural pathway were traced using retrograde tracing and immunofluorescence staining. Optogenetics and Chemogenetics were employed to manipulate DAergic neurons in the VTA and their axons in the rACC. RESULTS The ipsilateral PWTs in male C57BL/6 J mice significantly decreased after surgery, returning to baseline after seven days. Conversely, in CSDS mice, ipsilateral PWTs remained reduced for at least 30 days post-incision. A significant reduction in TH-positive neurons expressing c-Fos in the VTA of CPP mice was observed 15 days post-incision. Activating DAergic neurons significantly improved ipsilateral PWTs and locomotor performance in the OFT and EPM in CPP mice post-incision. Additionally, D1 expression in the rACC was found to decrease in CPP mice, and this reduction counteracted the increase in PWTs caused by activating DAergic neuron axon terminals in the rACC. CONCLUSION CSDS results in chronicity of postsurgical nociception and anxiety-like negative emotions, with alterations in DA transmission playing a role in CPP. Specific activation of DAergic neurons mitigates nociceptive responses and anxiety-like bahaviors, possibly mediated by D1 receptors in the rACC.
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Affiliation(s)
- Weizhen Liu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
- The Academy of Medical Sciences of Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Wang Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
- The Academy of Medical Sciences of Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Ziliang Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
- The Academy of Medical Sciences of Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Ying Xing
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China.
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4
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Salinas-Hernández XI, Zafiri D, Sigurdsson T, Duvarci S. Functional architecture of dopamine neurons driving fear extinction learning. Neuron 2023; 111:3854-3870.e5. [PMID: 37741275 DOI: 10.1016/j.neuron.2023.08.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/17/2023] [Accepted: 08/23/2023] [Indexed: 09/25/2023]
Abstract
The ability to extinguish fear responses to stimuli that no longer predict danger is critical for adaptive behavior and increases the likelihood of survival. During fear extinction, dopamine (DA) neurons signal the absence of the expected aversive outcome, and this extinction prediction error (EPE) signal is crucial for initiating and driving extinction learning. However, the neural circuits underlying the EPE signal have remained elusive. Here, we investigate the input-output circuitry of EPE-encoding DA neurons in male mice. By employing projection-specific fiber photometry and optogenetics, we demonstrate that these neurons project to a restricted subregion of the nucleus accumbens. Comprehensive anatomical analyses, as well as projection-specific chemogenetic manipulations combined with recordings of DA biosensors, further uncover the dorsal raphe as one key input structure critical for generating the EPE signal. Together, our results reveal for the first time the functional architecture of EPE-encoding DA neurons crucial for driving fear extinction learning.
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Affiliation(s)
- Ximena I Salinas-Hernández
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Daphne Zafiri
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Sevil Duvarci
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt, Germany.
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5
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Villar ME, Pavão-Delgado M, Amigo M, Jacob PF, Merabet N, Pinot A, Perry SA, Waddell S, Perisse E. Differential coding of absolute and relative aversive value in the Drosophila brain. Curr Biol 2022; 32:4576-4592.e5. [DOI: 10.1016/j.cub.2022.08.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/24/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022]
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6
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Strickland JA, Dileo AD, Moaddab M, Ray MH, Walker RA, Wright KM, McDannald MA. Foot shock facilitates reward seeking in an experience-dependent manner. Behav Brain Res 2021; 399:112974. [PMID: 33144178 PMCID: PMC7855116 DOI: 10.1016/j.bbr.2020.112974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/01/2020] [Accepted: 10/19/2020] [Indexed: 02/06/2023]
Abstract
Animals organize reward seeking around aversive events. An abundance of research shows that foot shock, as well as a shock-associated cue, can elicit freezing and suppress reward seeking. Yet, there is evidence that experience can flip the effect of foot shock to facilitate reward seeking. Here we examined cue suppression, foot shock suppression and foot shock facilitation of reward seeking in a single behavioural setting. Male Long Evans rats received fear discrimination consisting of danger, uncertainty, and safety cues. Discrimination took place over a baseline of rewarded nose poking. With limited experience (1-2 sessions), all cues and foot shock suppressed reward seeking. With continued experience (10-16 sessions), suppression became specific to shock-associated cues, foot shock briefly suppressed, then facilitated reward seeking. Our results provide a means of assessing positive properties of foot shock, and may provide insight into maladaptive behaviour around aversive events.
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Affiliation(s)
- J A Strickland
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA.
| | - A D Dileo
- Tufts University School of Medicine, School of Graduate Biomedical Sciences, Boston, MA, USA
| | - M Moaddab
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA
| | - M H Ray
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA
| | - R A Walker
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA
| | - K M Wright
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA
| | - M A McDannald
- Boston College, Department of Psychology & Neuroscience, Chestnut Hill, MA, USA.
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Soleimanpour E, Bergado Acosta JR, Landgraf P, Mayer D, Dankert E, Dieterich DC, Fendt M. Regulation of CREB Phosphorylation in Nucleus Accumbens after Relief Conditioning. Cells 2021; 10:238. [PMID: 33530478 PMCID: PMC7912172 DOI: 10.3390/cells10020238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/15/2021] [Accepted: 01/22/2021] [Indexed: 11/16/2022] Open
Abstract
Relief learning is the association of environmental cues with the cessation of aversive events. While there is increasing knowledge about the neural circuitry mediating relief learning, the respective molecular pathways are not known. Therefore, the aim of the present study was to examine different putative molecular pathways underlying relief learning. To this purpose, male rats were subjected either to relief conditioning or to a pseudo conditioning procedure. Forty-five minutes or 6 h after conditioning, samples of five different brain regions, namely the prefrontal cortex, nucleus accumbens (NAC), dorsal striatum, dorsal hippocampus, and amygdala, were collected. Using quantitative Western blots, the expression level of CREB, pCREB, ERK1/2, pERK1/2, CaMKIIα, MAP2K, PKA, pPKA, Akt, pAkt, DARPP-32, pDARPP-32, 14-3-3, and neuroligin2 were studied. Our analyses revealed that relief conditioned rats had higher CREB phosphorylation in NAC 6 h after conditioning than pseudo conditioned rats. The data further revealed that this CREB phosphorylation was mainly induced by dopamine D1 receptor-mediated activation of PKA, however, other kinases, downstream of the NMDA receptor, may also contribute. Taken together, the present study suggests that CREB phosphorylation, induced by a combination of different molecular pathways downstream of dopamine D1 and NMDA receptors, is essential for the acquisition and consolidation of relief learning.
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Affiliation(s)
- Elaheh Soleimanpour
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
| | - Jorge R. Bergado Acosta
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Peter Landgraf
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
| | - Dana Mayer
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
| | - Evelyn Dankert
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
| | - Daniela C. Dieterich
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (J.R.B.A.); (P.L.); (D.M.); (E.D.); (D.C.D.); (M.F.)
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany
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8
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Mayer FP, Iwamoto H, Hahn MK, Grumbar GJ, Stewart A, Li Y, Blakely RD. There's no place like home? Return to the home cage triggers dopamine release in the mouse nucleus accumbens. Neurochem Int 2021; 142:104894. [PMID: 33161093 PMCID: PMC7779706 DOI: 10.1016/j.neuint.2020.104894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 10/23/2022]
Abstract
Various stimuli have been employed as reinforcers in preclinical rodent models to elucidate the underpinnings of reward at a molecular and circuit level, with the release of dopamine (DA) in the nucleus accumbens (NAc) as a well-replicated, physiological correlate. Many factors, however, including strain differences, sex, prior stress, and reinforcer administration protocols can influence reward responding and DA release. Although previous evidence indicates that access to the home cage can be an effective reinforcer in behavioral tasks, whether this simple environmental manipulation can trigger DA release in the NAc has not been demonstrated. Here, using fiber photometric recordings of in vivo NAc dopamine release from a genetically-encoded DA sensor, we show that the movement of animals from the home cage to a clear, polycarbonate recording chamber evokes little to no DA release following initial exposure whereas returning animals from the recording chamber to a clean, home-like cage or to the home cage robustly triggers the release of DA, comparable in size to that observed with a 10 mg/kg i.p. Cocaine injection in the recording chamber. Although DA release can be evoked in moving mice to a clean cage, this release was significantly augmented when moving animals from the clean cage to the home cage. Our data provide direct evidence that home cage return from a foreign environment results in a biochemical change consistent with that of a rewarding stimulus. This simple environmental manipulation provides a minimally invasive approach to study the reward circuitry underlying an ethologically relevant reinforcer, return to the safe confines of "home". The home cage - DA release paradigm may also represent a biomarker-driven paradigm for the evaluation of genetic and experiential events that underlie anhedonic states, characteristic of major mood disorders, and to present new opportunities to identify their treatments.
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Affiliation(s)
- Felix P Mayer
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Hideki Iwamoto
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Maureen K Hahn
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Gregory J Grumbar
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Adele Stewart
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Yulong Li
- Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA.
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9
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Liu J, Likhtik E, Shereen AD, Dennis-Tiwary TA, Casaccia P. White Matter Plasticity in Anxiety: Disruption of Neural Network Synchronization During Threat-Safety Discrimination. Front Cell Neurosci 2020; 14:587053. [PMID: 33250713 PMCID: PMC7674975 DOI: 10.3389/fncel.2020.587053] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/02/2020] [Indexed: 12/11/2022] Open
Abstract
Recent evidence highlighted the importance of white matter tracts in typical and atypical behaviors. White matter dynamically changes in response to learning, stress, and social experiences. Several lines of evidence have reported white matter dysfunction in psychiatric conditions, including depression, stress- and anxiety-related disorders. The mechanistic underpinnings of these associations, however, remain poorly understood. Here, we outline an integrative perspective positing a link between aberrant myelin plasticity and anxiety. Drawing on extant literature and emerging new findings, we suggest that in anxiety, unique changes may occur in response to threat and to safety learning and the ability to discriminate between both types of stimuli. We propose that altered myelin plasticity in the neural circuits underlying these two forms of learning relates to the emergence of anxiety-related disorders, by compromising mechanisms of neural network synchronization. The clinical and translational implications of this model for anxiety-related disorders are discussed.
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Affiliation(s)
- Jia Liu
- Advanced Science Research Center at the Graduate Center, Neuroscience Initiative, City University of New York, New York, NY, United States
| | - Ekaterina Likhtik
- Department of Biology, Hunter College, City University of New York, New York, NY, United States
- Graduate Program in Biology at the Graduate Center, City University of New York, New York, NY, United States
| | - A. Duke Shereen
- Advanced Science Research Center at the Graduate Center, Neuroscience Initiative, City University of New York, New York, NY, United States
| | - Tracy A. Dennis-Tiwary
- Department of Psychology, Hunter College, City University of New York, New York, NY, United States
- Graduate Program in Psychology and Behavioral and Cognitive Neuroscience at the Graduate Center, City University of New York, New York, NY, United States
| | - Patrizia Casaccia
- Advanced Science Research Center at the Graduate Center, Neuroscience Initiative, City University of New York, New York, NY, United States
- Graduate Program in Biology at the Graduate Center, City University of New York, New York, NY, United States
- Graduate Program in Biochemistry at the Graduate Center, City University of New York, New York, NY, United States
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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10
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Individual expression of conditioned safety but not of conditioned relief is correlated with contextual fear. Behav Brain Res 2020; 393:112799. [DOI: 10.1016/j.bbr.2020.112799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/19/2020] [Accepted: 07/05/2020] [Indexed: 11/20/2022]
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Kreutzmann JC, Fendt M. Chronic inhibition of GABA synthesis in the infralimbic cortex facilitates conditioned safety memory and reduces contextual fear. Transl Psychiatry 2020; 10:120. [PMID: 32332716 PMCID: PMC7182568 DOI: 10.1038/s41398-020-0788-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/12/2020] [Accepted: 03/25/2020] [Indexed: 12/20/2022] Open
Abstract
Accurate discrimination between danger and safety cues is essential for survival. Recent findings in humans indicate that patients suffering from anxiety disorders cannot reliably use safety cues in order to inhibit fear responses. However, the neuroanatomical pathways of conditioned safety are still unclear. Aim of the present study was to investigate whether chronic inhibition of GABA synthesis in the infralimbic (IL) cortex, a critical region for fear inhibition, would lead to enhanced conditioned safety memory. Male Sprague Dawley rats were equipped with osmotic mini-pumps attached to an infusion cannula aimed at the IL. Mini-pumps were either filled with the glutamate decarboxylase (GAD) inhibitor L-allylglycine (L-AG) or the inactive enantiomer D-allylglycine (D-AG). Previous studies demonstrated that chronic infusions of L-AG lead to lower GABA levels and overall enhanced neural activity. The effect of IL disinhibition on conditioned safety was investigated utilizing the acoustic startle response. Chronic disinhibition of the IL facilitated conditioned safety memory, along with reduced contextual fear and lower corticosterone levels. The present findings suggest that the IL is a key brain region for conditioned safety memory. Because anxiety disorder patients are often not capable to use safety cues to inhibit unnecessary fear responses, the present findings are of clinical relevance and could potentially contribute to therapy optimization.
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Affiliation(s)
- Judith C. Kreutzmann
- grid.5807.a0000 0001 1018 4307Institute for Pharmacology & Toxicology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany ,grid.418723.b0000 0001 2109 6265Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Markus Fendt
- grid.5807.a0000 0001 1018 4307Institute for Pharmacology & Toxicology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany ,grid.5807.a0000 0001 1018 4307Center of Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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12
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Kreutzmann JC, Jovanovic T, Fendt M. Infralimbic cortex activity is required for the expression but not the acquisition of conditioned safety. Psychopharmacology (Berl) 2020; 237:2161-2172. [PMID: 32363439 PMCID: PMC7306044 DOI: 10.1007/s00213-020-05527-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 04/13/2020] [Indexed: 02/06/2023]
Abstract
The ability to discriminate between danger and safety is crucial for survival across species. Whereas danger signals predict the onset of a potentially threatening event, safety signals indicate the non-occurrence of an aversive event, thereby reducing fear and stress responses. While the neural basis of conditioned safety remains to be elucidated, fear extinction studies provide evidence that the infralimbic cortex (IL) modulates fear inhibition. In the current study, the IL was temporarily inactivated with local muscimol injections in male and female rats. The effect of IL inactivation on the acquisition and expression of conditioned safety was investigated utilizing the startle response. Temporary inactivation of the IL prior to conditioning did not affect the acquisition of conditioned safety, whereas IL inactivation during the expression test completely blocked the expression of conditioned safety in male and female rats. Inactivation of the neighboring prelimbic (PL) cortex during the expression test did not affect the expression of safety memory. Our findings suggest that the IL is a critical brain region for the expression of safety memory. Because patients suffering from anxiety disorders are often unable to make use of safety cues to inhibit fear, the present findings are of clinical relevance and could potentially contribute to therapy optimization of anxiety-related psychiatric disorders.
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Affiliation(s)
- Judith C Kreutzmann
- Medical Faculty, Institute for Pharmacology & Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany.
- Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University Detroit, Detroit, MI, USA
| | - Markus Fendt
- Medical Faculty, Institute for Pharmacology & Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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13
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Gerber B, König C, Fendt M, Andreatta M, Romanos M, Pauli P, Yarali A. Timing-dependent valence reversal: a principle of reinforcement processing and its possible implications. Curr Opin Behav Sci 2019. [DOI: 10.1016/j.cobeha.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Runegaard AH, Fitzpatrick CM, Woldbye DPD, Andreasen JT, Sørensen AT, Gether U. Modulating Dopamine Signaling and Behavior with Chemogenetics: Concepts, Progress, and Challenges. Pharmacol Rev 2019; 71:123-156. [PMID: 30814274 DOI: 10.1124/pr.117.013995] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
For more than 60 years, dopamine (DA) has been known as a critical modulatory neurotransmitter regulating locomotion, reward-based motivation, and endocrine functions. Disturbances in DA signaling have been linked to an array of different neurologic and psychiatric disorders, including Parkinson's disease, schizophrenia, and addiction, but the underlying pathologic mechanisms have never been fully elucidated. One major obstacle limiting interpretation of standard pharmacological and transgenic interventions is the complexity of the DA system, which only appears to widen as research progresses. Nonetheless, development of new genetic tools, such as chemogenetics, has led to an entirely new era for functional studies of neuronal signaling. By exploiting receptors that are engineered to respond selectively to an otherwise inert ligand, so-called Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), chemogenetics enables pharmacological remote control of neuronal activity. Here we review the recent, extensive application of this technique to the DA field and how its use has advanced the study of the DA system and contributed to our general understanding of DA signaling and related behaviors. Moreover, we discuss the challenges and pitfalls associated with the chemogenetic technology, such as the metabolism of the DREADD ligand clozapine N-oxide (CNO) to the D2 receptor antagonist clozapine. We conclude that despite the recent concerns regarding CNO, the chemogenetic toolbox provides an exceptional approach to study neuronal function. The huge potential should promote continued investigations and additional refinements to further expound key mechanisms of DA signaling and circuitries in normal as well as maladaptive behaviors.
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Affiliation(s)
- Annika Højrup Runegaard
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ciarán Martin Fitzpatrick
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - David Paul Drucker Woldbye
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Tobias Andreasen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Toft Sørensen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience (A.H.R., D.P.D.W., A.T.S., U.G.) and Department of Drug Design and Pharmacology (C.M.F., J.T.A.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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15
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Zorzo C, Méndez-López M, Méndez M, Arias JL. Adult social isolation leads to anxiety and spatial memory impairment: Brain activity pattern of COx and c-Fos. Behav Brain Res 2019; 365:170-177. [PMID: 30851318 DOI: 10.1016/j.bbr.2019.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/19/2019] [Accepted: 03/05/2019] [Indexed: 12/22/2022]
Abstract
Social isolation during adulthood is a frequent problem that leads to a large variety of adverse emotional and cognitive effects. However, most of the social isolation rodent procedures begin the separation early post-weaning. This work explores locomotor activity, anxiety-like behaviour, and spatial working memory after twelve weeks of adult social isolation. In order to study the functional contribution of selected brain areas following a working memory task, we assessed neuronal metabolic activity through quantitative cytochrome oxidase histochemistry and c-Fos immunohistochemistry. Behaviourally, we found that isolated animals (IS) showed anxiety-like behaviour and worse working memory than controls, whereas motor functions were preserved. Moreover, IS rats showed lower levels of learning-related c-Fos immunoreactivity, compared to controls, in the medial prefrontal cortex (mPFC), ventral tegmental area (VTA), and nucleus accumbens shell. In addition, the IS group showed lower neuronal metabolic activity in the mPFC, VTA, and CA1 subfield of the hippocampus. These results indicate that twelve weeks of social isolation in adult rats leads to different behavioural and brain alterations, and they highlight the importance of social support, not only in development, but also in adulthood.
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Affiliation(s)
- Candela Zorzo
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
| | - Magdalena Méndez-López
- IIS Aragón, Departamento de Psicología y Sociología, Universidad de Zaragoza, Zaragoza, Spain.
| | - Marta Méndez
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
| | - Jorge L Arias
- Departamento de Psicología, Instituto de Neurociencias del Principado de Asturias (INEUROPA), Universidad de Oviedo, Plaza Feijoo s/n, 33003, Oviedo, Spain.
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16
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Li H, Pullmann D, Cho JY, Eid M, Jhou TC. Generality and opponency of rostromedial tegmental (RMTg) roles in valence processing. eLife 2019; 8:41542. [PMID: 30667358 PMCID: PMC6361585 DOI: 10.7554/elife.41542] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 01/04/2019] [Indexed: 12/31/2022] Open
Abstract
The rostromedial tegmental nucleus (RMTg), a GABAergic afferent to midbrain dopamine (DA) neurons, has been hypothesized to be broadly activated by aversive stimuli. However, this encoding pattern has only been demonstrated for a limited number of stimuli, and the RMTg influence on ventral tegmental (VTA) responses to aversive stimuli is untested. Here, we found that RMTg neurons are broadly excited by aversive stimuli of different sensory modalities and inhibited by reward-related stimuli. These stimuli include visual, auditory, somatosensory and chemical aversive stimuli, as well as “opponent” motivational states induced by removal of sustained rewarding or aversive stimuli. These patterns are consistent with broad encoding of negative valence in a subset of RMTg neurons. We further found that valence-encoding RMTg neurons preferentially project to the DA-rich VTA versus other targets, and excitotoxic RMTg lesions greatly reduce aversive stimulus-induced inhibitions in VTA neurons, particularly putative DA neurons, while also impairing conditioned place aversion to multiple aversive stimuli. Together, our findings indicate a broad RMTg role in encoding aversion and driving VTA responses and behavior.
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Affiliation(s)
- Hao Li
- Department of Neuroscience, Medical University of South Carolina, Charleston, United States
| | - Dominika Pullmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, United States
| | - Jennifer Y Cho
- Department of Neuroscience, Medical University of South Carolina, Charleston, United States
| | - Maya Eid
- Department of Neuroscience, Medical University of South Carolina, Charleston, United States
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17
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Wotjak CT. Sound check, stage design and screen plot - how to increase the comparability of fear conditioning and fear extinction experiments. Psychopharmacology (Berl) 2019; 236:33-48. [PMID: 30470861 PMCID: PMC6373201 DOI: 10.1007/s00213-018-5111-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/05/2018] [Indexed: 11/16/2022]
Abstract
In the recent decade, fear conditioning has evolved as a standard procedure for testing cognitive abilities such as memory acquisition, consolidation, recall, reconsolidation, and extinction, preferentially in genetically modified mice. The reasons for the popularity of this powerful approach are its ease to perform, the short duration of training and testing, and its well-described neural basis. So why to bother about flaws in standardization of test procedures and analytical routines? Simplicity does not preclude the existence of fallacies. A short survey of the literature revealed an indifferent use of acoustic stimuli in terms of quality (i.e., white noise vs. sine wave), duration, and intensity. The same applies to the shock procedures. In the present article, I will provide evidence for the importance of qualitative and quantitative parameters of conditioned and unconditioned stimuli for the experimental outcome. Moreover, I will challenge frequently applied interpretations of short-term vs. long-term extinction and spontaneous recovery. On the basis of these concerns, I suggest a guideline for standardization of fear conditioning experiments in mice to improve the comparability of the experimental data.
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Affiliation(s)
- Carsten T. Wotjak
- 0000 0000 9497 5095grid.419548.5Max Planck Institute of Psychiatry, RG “Neuronal Plasticity”, Kraepelinstr. 2-10, 80804 Munich, Germany
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18
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Salinas-Hernández XI, Vogel P, Betz S, Kalisch R, Sigurdsson T, Duvarci S. Dopamine neurons drive fear extinction learning by signaling the omission of expected aversive outcomes. eLife 2018; 7:38818. [PMID: 30421719 PMCID: PMC6257816 DOI: 10.7554/elife.38818] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 11/08/2018] [Indexed: 01/15/2023] Open
Abstract
Extinction of fear responses is critical for adaptive behavior and deficits in this form of safety learning are hallmark of anxiety disorders. However, the neuronal mechanisms that initiate extinction learning are largely unknown. Here we show, using single-unit electrophysiology and cell-type specific fiber photometry, that dopamine neurons in the ventral tegmental area (VTA) are activated by the omission of the aversive unconditioned stimulus (US) during fear extinction. This dopamine signal occurred specifically during the beginning of extinction when the US omission is unexpected, and correlated strongly with extinction learning. Furthermore, temporally-specific optogenetic inhibition or excitation of dopamine neurons at the time of the US omission revealed that this dopamine signal is both necessary for, and sufficient to accelerate, normal fear extinction learning. These results identify a prediction error-like neuronal signal that is necessary to initiate fear extinction and reveal a crucial role of DA neurons in this form of safety learning. To survive, animals must identify and react to stimuli in their environment that signal danger. But they must also adapt their behavior when those stimuli no longer signal danger – hiding whenever you hear a loud noise might keep you safe, but it also prevents you from searching for food. In the laboratory, we can study this form of learning using procedures called fear conditioning and extinction. During fear conditioning, animals learn that a stimulus, such as a tone, signals that an unpleasant event is about to occur. That event might involve receiving a mild shock to the foot, for example. After experiencing the tone and shock paired together multiple times, animals will initially show signs of fear – such as freezing – when they hear the tone. But if later the tone occurs without being followed by the shock, these fear responses fade. This fading process is called extinction. Extinction does not involve erasing the old memory about the tone-shock relationship. That is, it is not a form of forgetting. Instead, the animals learn that the tone no longer signals an impending shock. By monitoring brain activity in mice trained to associate a shock with a tone, Salinas-Hernández et al. reveal how the brain begins to learn that the shock no longer follows the tone. When the mice do not receive the anticipated shock to the foot, a group of brain cells that produce the chemical dopamine increase their activity. These neurons also fire whenever animals receive a reward, particularly one that exceeds their expectations. The more the dopamine neurons fire, the faster the mice reduce their fear responses to the tone. Preventing the neurons from increasing their activity prevents the mice from extinguishing their fear memory. By contrast, activating the neurons speeds up the extinction process. Understanding how the brain extinguishes learned fear responses has therapeutic implications. Many anxiety disorders, such as post-traumatic stress disorder, involve impaired fear extinction learning. Indeed, exposure therapy – used to treat anxiety disorders such as phobias – is a form of fear extinction. Manipulating the activity of dopamine neurons during extinction could therefore help to treat anxiety disorders.
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Affiliation(s)
| | - Pascal Vogel
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Sebastian Betz
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Raffael Kalisch
- Deutsches Resilienz Zentrum, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.,Neuroimaging Center, Focus Program Translational Neuroscience, Johannes Gutenberg University, Mainz, Germany
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Sevil Duvarci
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
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19
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Sharpe MJ. What a relief! A role for dopamine in positive (but not negative) valence. Neuropsychopharmacology 2018. [PMID: 29520057 PMCID: PMC6002543 DOI: 10.1038/s41386-018-0036-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have long known that dopamine encodes the predictive relationship between cues and rewards. But what about relief learning? In this issue of Neuropsychopharmacology, Mayer et al. show that the same circuits encoding rewarding events also encode relief from aversive events. And this appears to be in a manner distinct from encoding of the aversive event itself. So does dopamine only contribute to learning about positive events? And are these events encoded in the same way regardless of how that positive experience came about? Not quite. Turns out, the devil is in the details.
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Affiliation(s)
- Melissa J Sharpe
- National Institute on Drug Abuse, Baltimore, MD, 21224, USA. .,Princeton Neuroscience Institute, Princeton, NJ, 08544, USA. .,School of Psychology, UNSW Australia, Sydney, USA.
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20
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Abstract
Overcoming aversive emotional memories requires neural systems that detect when fear responses are no longer appropriate so that they can be extinguished. The midbrain ventral tegmental area (VTA) dopamine system has been implicated in reward and more broadly in signaling when a better-than-expected outcome has occurred. This suggests that it may be important in guiding fear to safety transitions. We report that when an expected aversive outcome does not occur, activity in midbrain dopamine neurons is necessary to extinguish behavioral fear responses and engage molecular signaling events in extinction learning circuits. Furthermore, a specific dopamine projection to the nucleus accumbens medial shell is partially responsible for this effect. In contrast, a separate dopamine projection to the medial prefrontal cortex opposes extinction learning. This demonstrates a novel function for the canonical VTA-dopamine reward system and reveals opposing behavioral roles for different dopamine neuron projections in fear extinction learning. Fear memories are overcome only when it is ascertained that fearful responses are not appropriate. Here the authors demonstrate that activity in dopamine neurons is necessary to extinguish fear responses and two distinct dopamine neuron projections exert opposing effects on extinction learning.
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