1
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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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2
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Sepahvand T, Power KD, Qin T, Yuan Q. The Basolateral Amygdala: The Core of a Network for Threat Conditioning, Extinction, and Second-Order Threat Conditioning. BIOLOGY 2023; 12:1274. [PMID: 37886984 PMCID: PMC10604397 DOI: 10.3390/biology12101274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/14/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
Threat conditioning, extinction, and second-order threat conditioning studied in animal models provide insight into the brain-based mechanisms of fear- and anxiety-related disorders and their treatment. Much attention has been paid to the role of the basolateral amygdala (BLA) in such processes, an overview of which is presented in this review. More recent evidence suggests that the BLA serves as the core of a greater network of structures in these forms of learning, including associative and sensory cortices. The BLA is importantly regulated by hippocampal and prefrontal inputs, as well as by the catecholaminergic neuromodulators, norepinephrine and dopamine, that may provide important prediction-error or learning signals for these forms of learning. The sensory cortices may be required for the long-term storage of threat memories. As such, future research may further investigate the potential of the sensory cortices for the long-term storage of extinction and second-order conditioning memories.
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Affiliation(s)
| | | | | | - Qi Yuan
- Biomedical Sciences, Faculty of Medicine, Memorial University, St John’s, NL A1B 3V6, Canada; (T.S.); (K.D.P.); (T.Q.)
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3
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Raj V, Thekkuveettil A. Dopamine plays a critical role in the olfactory adaptive learning pathway in Caenorhabditis elegans. J Neurosci Res 2022; 100:2028-2043. [PMID: 35906758 DOI: 10.1002/jnr.25112] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/26/2022] [Accepted: 07/16/2022] [Indexed: 11/11/2022]
Abstract
Encoding and consolidating information through learning and memory is vital in adaptation and survival. Dopamine (DA) is a critical neurotransmitter that modulates behavior. However, the role of DA in learning and memory processes is not well defined. Herein, we used the olfactory adaptive learning paradigm in Caenorhabditis elegans to elucidate the role of DA in the memory pathway. Cat-2 mutant worms with low DA synthesis showed a significant reduction in chemotaxis index (CI) compared to the wild type (WT) after short-term conditioning. In dat-1::ICE worms, having degeneration of DA neurons, there was a significant reduction in adaptive learning and memory. When the worms were trained in the presence of exogenous DA (10 mM) instead of food, a substantial increase in CI value was observed. Furthermore, our results suggest that both dop-1 and dop-3 DA receptors are involved in memory retention. The release of DA during conditioning is essential to initiate the learning pathway. We also noted an enhanced cholinergic receptor activity in the absence of dopaminergic neurons. The strains expressing GCaMP6 in DA neurons (pdat-1::GCaMP-6::mCherry) showed a rise in intracellular calcium influx in the presence of the conditional stimulus after training, suggesting DA neurons are activated during memory recall. These results reveal the critical role of DA in adaptive learning and memory, indicating that DA neurons play a crucial role in the effective processing of cognitive function.
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Affiliation(s)
- Vishnu Raj
- Division of Molecular Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, BMT Wing, Trivandrum, India
| | - Anoopkumar Thekkuveettil
- Division of Molecular Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, BMT Wing, Trivandrum, India
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4
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Beloate LN, Zhang N. Connecting the dots between cell populations, whole-brain activity, and behavior. NEUROPHOTONICS 2022; 9:032208. [PMID: 35350137 PMCID: PMC8957372 DOI: 10.1117/1.nph.9.3.032208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Simultaneously manipulating and monitoring both microscopic and macroscopic brain activity in vivo and identifying the linkage to behavior are powerful tools in neuroscience research. These capabilities have been realized with the recent technical advances of optogenetics and its combination with fMRI, here termed "opto-fMRI." Opto-fMRI allows for targeted brain region-, cell-type-, or projection-specific manipulation and targeted Ca 2 + activity measurement to be linked with global brain signaling and behavior. We cover the history, technical advances, applications, and important considerations of opto-fMRI in anesthetized and awake rodents and the future directions of the combined techniques in neuroscience and neuroimaging.
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Affiliation(s)
- Lauren N. Beloate
- Pennsylvania State University, Department of Biomedical Engineering, Pennsylvania, United States
| | - Nanyin Zhang
- Pennsylvania State University, Department of Biomedical Engineering, Pennsylvania, United States
- Pennsylvania State University, Huck Institutes of the Life Sciences, Pennsylvania, United States
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5
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Sayegh F, Herraiz L, Colom M, Lopez S, Rampon C, Dahan L. D1/5 dopamine receptors are necessary for learning a novel context. Learn Mem 2022; 29:142-145. [PMID: 35577394 DOI: 10.1101/lm.053555.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/23/2022] [Indexed: 11/24/2022]
Abstract
Dopamine participates in encoding memories and could either encode rewarding/aversive value of unconditioned stimuli or act as a novelty signal triggering contextual learning. Here we show that intraperitoneal injection of the dopamine D1/5R antagonist SCH23390 impairs contextual fear conditioning and tone-shock association, while intrahippocampal injection only impairs contextual fear conditioning. By using the context pre-exposure facilitation effect test, we show that SCH23390 is able to block the encoding of the context during the pre-exposure phase. Thus, we provide additional evidence that dopamine is involved in encoding conjunctive representations of new contexts.
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Affiliation(s)
- Fares Sayegh
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
| | - Laurie Herraiz
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
| | - Morgane Colom
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
| | - Sébastien Lopez
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
| | - Claire Rampon
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse 31062, France
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6
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Seeking motivation and reward: roles of dopamine, hippocampus and supramammillo-septal pathway. Prog Neurobiol 2022; 212:102252. [PMID: 35227866 PMCID: PMC8961455 DOI: 10.1016/j.pneurobio.2022.102252] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 02/09/2022] [Accepted: 02/23/2022] [Indexed: 01/07/2023]
Abstract
Reinforcement learning and goal-seeking behavior are thought to be mediated by midbrain dopamine neurons. However, little is known about neural substrates of curiosity and exploratory behavior, which occur in the absence of clear goal or reward. This is despite behavioral scientists having long suggested that curiosity and exploratory behaviors are regulated by an innate drive. We refer to such behavior as information-seeking behavior and propose 1) key neural substrates and 2) the concept of environment prediction error as a framework to understand information-seeking processes. The cognitive aspect of information-seeking behavior, including the perception of salience and uncertainty, involves, in part, the pathways from the posterior hypothalamic supramammillary region to the hippocampal formation. The vigor of such behavior is modulated by the following: supramammillary glutamatergic neurons; their projections to medial septal glutamatergic neurons; and the projections of medial septal glutamatergic neurons to ventral tegmental dopaminergic neurons. Phasic responses of dopaminergic neurons are characterized as signaling potentially important stimuli rather than rewards. This paper describes how novel stimuli and uncertainty trigger seeking motivation and how these neural substrates modulate information-seeking behavior.
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7
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Midbrain dopaminergic innervation of the hippocampus is sufficient to modulate formation of aversive memories. Proc Natl Acad Sci U S A 2021; 118:2111069118. [PMID: 34580198 DOI: 10.1073/pnas.2111069118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2021] [Indexed: 11/18/2022] Open
Abstract
Aversive memories are important for survival, and dopaminergic signaling in the hippocampus has been implicated in aversive learning. However, the source and mode of action of hippocampal dopamine remain controversial. Here, we utilize anterograde and retrograde viral tracing methods to label midbrain dopaminergic projections to the dorsal hippocampus. We identify a population of midbrain dopaminergic neurons near the border of the substantia nigra pars compacta and the lateral ventral tegmental area that sends direct projections to the dorsal hippocampus. Using optogenetic manipulations and mutant mice to control dopamine transmission in the hippocampus, we show that midbrain dopamine potently modulates aversive memory formation during encoding of contextual fear. Moreover, we demonstrate that dopaminergic transmission in the dorsal CA1 is required for the acquisition of contextual fear memories, and that this acquisition is sustained in the absence of catecholamine release from noradrenergic terminals. Our findings identify a cluster of midbrain dopamine neurons that innervate the hippocampus and show that the midbrain dopamine neuromodulation in the dorsal hippocampus is sufficient to maintain aversive memory formation.
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8
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Fleming W, Jewell S, Engelhard B, Witten DM, Witten IB. Inferring spikes from calcium imaging in dopamine neurons. PLoS One 2021; 16:e0252345. [PMID: 34086726 PMCID: PMC8177503 DOI: 10.1371/journal.pone.0252345] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/12/2021] [Indexed: 11/18/2022] Open
Abstract
Calcium imaging has led to discoveries about neural correlates of behavior in subcortical neurons, including dopamine (DA) neurons. However, spike inference methods have not been tested in most populations of subcortical neurons. To address this gap, we simultaneously performed calcium imaging and electrophysiology in DA neurons in brain slices and applied a recently developed spike inference algorithm to the GCaMP fluorescence. This revealed that individual spikes can be inferred accurately in this population. Next, we inferred spikes in vivo from calcium imaging from these neurons during Pavlovian conditioning, as well as during navigation in virtual reality. In both cases, we quantitatively recapitulated previous in vivo electrophysiological observations. Our work provides a validated approach to infer spikes from calcium imaging in DA neurons and implies that aspects of both tonic and phasic spike patterns can be recovered.
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Affiliation(s)
- Weston Fleming
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America
| | - Sean Jewell
- Department of Statistics & Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Ben Engelhard
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America
| | - Daniela M. Witten
- Department of Statistics & Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Ilana B. Witten
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America
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9
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Moaddab M, McDannald MA. Retrorubral field is a hub for diverse threat and aversive outcome signals. Curr Biol 2021; 31:2099-2110.e5. [PMID: 33756109 DOI: 10.1016/j.cub.2021.02.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 01/13/2021] [Accepted: 02/25/2021] [Indexed: 01/16/2023]
Abstract
Adaptive fear scales to the degree of threat and requires diverse neural signals for threat and aversive outcome. We propose that the retrorubral field (RRF), a midbrain region containing A8 dopamine, is a neural origin of such signals. To reveal these signals, we recorded RRF single-unit activity while male rats discriminated danger, uncertainty, and safety. Many RRF neurons showed firing extremes to danger and safety that framed intermediate firing to uncertainty. The remaining neurons showed unique, threat-selective cue firing patterns. Diversity in firing direction, magnitude, and temporal characteristics led to the detection of at least eight functional neuron types. Neuron types defined with respect to threat showed unique firing patterns following aversive outcome. The result was RRF signals for foot shock receipt, positive prediction error, anti-positive prediction error, persistent safety, and persistent threat. The diversity of threat and aversive outcome signals points to a key role for the RRF in adaptive fear.
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Affiliation(s)
- Mahsa Moaddab
- Department of Psychology and Neuroscience, Boston College, Chestnut Hill, MA 02467, USA.
| | - Michael A McDannald
- Department of Psychology and Neuroscience, Boston College, Chestnut Hill, MA 02467, USA.
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10
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Laing BT, Siemian JN, Sarsfield S, Aponte Y. Fluorescence microendoscopy for in vivo deep-brain imaging of neuronal circuits. J Neurosci Methods 2021; 348:109015. [PMID: 33259847 PMCID: PMC8745022 DOI: 10.1016/j.jneumeth.2020.109015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 11/16/2022]
Abstract
Imaging neuronal activity in awake, behaving animals has become a groundbreaking method in neuroscience that has rapidly enhanced our understanding of how the brain works. In vivo microendoscopic imaging has enabled researchers to see inside the brains of experimental animals and thus has emerged as a technology fit to answer many experimental questions. By combining microendoscopy with cutting edge targeting strategies and sophisticated analysis tools, neuronal activity patterns that underlie changes in behavior and physiology can be identified. However, new users may find it challenging to understand the techniques and to leverage this technology to best suit their needs. Here we present a background and overview of the necessary components for performing in vivo optical calcium imaging and offer some detailed guidance for current recommended approaches.
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Affiliation(s)
- Brenton T Laing
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Justin N Siemian
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Sarah Sarsfield
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Yeka Aponte
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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11
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Cai LX, Pizano K, Gundersen GW, Hayes CL, Fleming WT, Holt S, Cox JM, Witten IB. Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times. eLife 2020; 9:54936. [PMID: 32519951 PMCID: PMC7363446 DOI: 10.7554/elife.54936] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 06/05/2020] [Indexed: 12/18/2022] Open
Abstract
Dopamine (DA) neurons are thought to encode reward prediction error (RPE), in addition to other signals, such as salience. While RPE is known to support learning, the role of salience in learning remains less clear. To address this, we recorded and manipulated VTA DA neurons in mice during fear extinction. We applied deep learning to classify mouse freezing behavior, eliminating the need for human scoring. Our fiber photometry recordings showed DA neurons in medial and lateral VTA have distinct activity profiles during fear extinction: medial VTA activity more closely reflected RPE, while lateral VTA activity more closely reflected a salience-like signal. Optogenetic inhibition of DA neurons in either region slowed fear extinction, with the relevant time period for inhibition differing across regions. Our results indicate salience-like signals can have similar downstream consequences to RPE-like signals, although with different temporal dependencies.
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Affiliation(s)
- Lili X Cai
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Katherine Pizano
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Gregory W Gundersen
- Department of Computer Science, Princeton University, Princeton, United States
| | - Cameron L Hayes
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Weston T Fleming
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Sebastian Holt
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Julia M Cox
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Ilana B Witten
- Princeton Neuroscience Institute, Princeton University, Princeton, United States.,Department of Psychology, Princeton University, Princeton, United States
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12
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A VTA to Basal Amygdala Dopamine Projection Contributes to Signal Salient Somatosensory Events during Fear Learning. J Neurosci 2020; 40:3969-3980. [PMID: 32277045 DOI: 10.1523/jneurosci.1796-19.2020] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 01/02/2023] Open
Abstract
The amygdala is a brain area critical for the formation of fear memories. However, the nature of the teaching signal(s) that drive plasticity in the amygdala are still under debate. Here, we use optogenetic methods to investigate the contribution of ventral tegmental area (VTA) dopamine neurons to auditory-cued fear learning in male mice. Using anterograde and retrograde labeling, we found that a sparse and relatively evenly distributed population of VTA neurons projects to the basal amygdala (BA). In vivo optrode recordings in behaving mice showed that many VTA neurons, among them putative dopamine neurons, are excited by footshocks, and acquire a response to auditory stimuli during fear learning. Combined cfos imaging and retrograde labeling in dopamine transporter (DAT) Cre mice revealed that a large majority of BA projectors (>95%) are dopamine neurons, and that BA projectors become activated by the tone-footshock pairing of fear learning protocols. Finally, silencing VTA dopamine neurons, or their axon terminals in the BA during the footshock, reduced the strength of fear memory as tested 1 d later, whereas silencing the VTA-central amygdala (CeA) projection had no effect. Thus, VTA dopamine neurons projecting to the BA contribute to fear memory formation, by coding for the saliency of the footshock event and by signaling such events to the basal amygdala.SIGNIFICANCE STATEMENT Powerful mechanisms of fear learning have evolved in animals and humans to enable survival. During fear conditioning, a sensory cue, such as a tone (the conditioned stimulus), comes to predict an innately aversive stimulus, such as a mild footshock (the unconditioned stimulus). A brain representation of the unconditioned stimulus must act as a teaching signal to instruct plasticity of the conditioned stimulus representation in fear-related brain areas. Here we show that dopamine neurons in the VTA that project to the basal amygdala contribute to such a teaching signal for plasticity, thereby facilitating the formation of fear memories. Knowledge about the role of dopamine in aversively motivated plasticity might allow further insights into maladaptive plasticities that underlie anxiety and post-traumatic stress disorders in humans.
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13
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Zhou Y, Qiu L, Wang H, Chen X. Induction of activity synchronization among primed hippocampal neurons out of random dynamics is key for trace memory formation and retrieval. FASEB J 2020; 34:3658-3676. [PMID: 31944374 PMCID: PMC7079015 DOI: 10.1096/fj.201902274r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/02/2019] [Accepted: 12/15/2019] [Indexed: 01/07/2023]
Abstract
Memory is thought to be encoded by sparsely distributed neuronal ensembles in memory‐related regions. However, it is unclear how memory‐eligible neurons react during learning to encode trace fear memory and how they retrieve a memory. We implemented a fiber‐optic confocal fluorescence endomicroscope to directly visualize calcium dynamics of hippocampal CA1 neurons in freely behaving mice subjected to trace fear conditioning. Here we report that the overall activity levels of CA1 neurons showed a right‐skewed lognormal distribution, with a small portion of highly active neurons (termed Primed Neurons) filling the long‐tail. Repetitive training induced Primed Neurons to shift from random activity to well‐tuned synchronization. The emergence of activity synchronization coincided with the appearance of mouse freezing behaviors. In recall, a partial synchronization among the same subset of Primed Neurons was induced from random dynamics, which also coincided with mouse freezing behaviors. Additionally, training‐induced synchronization facilitated robust calcium entry into Primed Neurons. In contrast, most CA1 neurons did not respond to tone and foot shock throughout the training and recall cycles. In conclusion, Primed Neurons are preferably recruited to encode trace fear memory and induction of activity synchronization among Primed Neurons out of random dynamics is critical for trace memory formation and retrieval.
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Affiliation(s)
- Yuxin Zhou
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
| | - Liyan Qiu
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
| | - Haiying Wang
- Department of Statistics, University of Connecticut, Storrs, CT, USA
| | - Xuanmao Chen
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
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14
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Velasco ER, Florido A, Milad MR, Andero R. Sex differences in fear extinction. Neurosci Biobehav Rev 2019; 103:81-108. [PMID: 31129235 DOI: 10.1016/j.neubiorev.2019.05.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/08/2019] [Accepted: 05/19/2019] [Indexed: 12/18/2022]
Abstract
Despite the exponential increase in fear research during the last years, few studies have included female subjects in their design. The need to include females arises from the knowledge gap of mechanistic processes underlying the behavioral and neural differences observed in fear extinction. Moreover, the exact contribution of sex and hormones in relation to learning and behavior is still largely unknown. Insights from this field could be beneficial as fear-related disorders are twice as prevalent in women compared to men. Here, we review an up-to-date summary of animal and human studies in adulthood that report sex differences in fear extinction from a structural and functional approach. Furthermore, we describe how these factors could contribute to the observed sex differences in fear extinction during normal and pathological conditions.
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Affiliation(s)
- E R Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - A Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - M R Milad
- Department of Psychiatry, University of Illinois at Chicago, USA
| | - R Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Corporació Sanitaria Parc Taulí, Sabadell, Spain; Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Spain.
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15
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Li H, Hou X, Lin R, Fan M, Pang S, Jiang L, Liu Q, Fu L. Advanced endoscopic methods in gastrointestinal diseases: a systematic review. Quant Imaging Med Surg 2019; 9:905-920. [PMID: 31281783 DOI: 10.21037/qims.2019.05.16] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Endoscopic imaging is the main method for detecting gastrointestinal diseases, which adversely affect human health. White light endoscopy (WLE) was the first method used for endoscopic examination and is still the preliminary step in the detection of gastrointestinal diseases during clinical examination. However, it cannot accurately diagnose gastrointestinal diseases owing to its poor correlation with histopathological diagnosis. In recent years, many advanced endoscopic methods have emerged to improve the detection accuracy by endoscopy. Chromoendoscopy (CE) enhances the contrast between normal and diseased tissues using biocompatible dye agents. Narrow band imaging (NBI) can improve the contrast between capillaries and submucosal vessels by changing the light source acting on the tissue using special filters to realize the visualization of the vascular structure. Flexible spectral imaging color enhancement (FICE) technique uses the reflectance spectrum estimation technique to obtain individual spectral images and reconstructs an enhanced image of the mucosal surface using three selected spectral images. The i-Scan technology takes advantage of the different reflective properties of normal and diseased tissues to obtain images, and enhances image contrast through post-processing algorithms. These abovementioned methods can be used to detect gastrointestinal diseases by observing the macroscopic structure of the digestive tract mucosa, but the ability of early cancer detection is limited with low resolution. However, based on the principle of confocal imaging, probe-based confocal laser endomicroscopy (pCLE) can enable cellular visualization with high-performance probes, which can present cellular morphology that is highly consistent with that shown by biopsy to provide the possibility of early detection of cancer. Other endoscopic imaging techniques including endoscopic optical coherence tomography (EOCT) and photoacoustic endoscopy (PAE), are also promising for diagnosing gastrointestinal diseases. This review focuses on these technologies and aims to provide an overview of different technologies and their clinical applicability.
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Affiliation(s)
- Hua Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaohua Hou
- Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Rong Lin
- Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Mengke Fan
- Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Suya Pang
- Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Longjie Jiang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qian Liu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ling Fu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
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16
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17
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Jo YS, Heymann G, Zweifel LS. Dopamine Neurons Reflect the Uncertainty in Fear Generalization. Neuron 2018; 100:916-925.e3. [PMID: 30318411 PMCID: PMC6226002 DOI: 10.1016/j.neuron.2018.09.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/13/2018] [Accepted: 09/17/2018] [Indexed: 12/20/2022]
Abstract
Generalized fear is a maladaptive behavior in which non-threatening stimuli elicit a fearful response. Here, we demonstrate that discrimination between predictive and non-predictive threat stimuli is highly sensitive to probabilistic discounting and increasing threat intensity in mice. We find that dopamine neurons of the ventral tegmental area (VTA) encode both the negative valence of threat-predictive cues and the certainty of threat prediction. As fear generalization emerges, the dopamine neurons that are activated by a threat predictive cue (CS+) decrease the amplitude of activation and an equivalent signal emerges to a non-predictive cue (CS-). Temporally precise enhancement of dopamine neurons during threat conditioning to high threat levels or uncertain threats can prevent generalization. Moreover, phasic enhancement of genetically captured dopamine neurons activated by threat cues can reverse fear generalization. These findings demonstrate the dopamine neurons reflect the certainty of threat prediction that can be used to inform and update the fear engram.
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Affiliation(s)
- Yong S Jo
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Gabriel Heymann
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Larry S Zweifel
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA; Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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18
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Tyree SM, de Lecea L. Lateral Hypothalamic Control of the Ventral Tegmental Area: Reward Evaluation and the Driving of Motivated Behavior. Front Syst Neurosci 2017; 11:50. [PMID: 28729827 PMCID: PMC5498520 DOI: 10.3389/fnsys.2017.00050] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/22/2017] [Indexed: 12/25/2022] Open
Abstract
The lateral hypothalamus (LH) plays an important role in many motivated behaviors, sleep-wake states, food intake, drug-seeking, energy balance, etc. It is also home to a heterogeneous population of neurons that express and co-express multiple neuropeptides including hypocretin (Hcrt), melanin-concentrating hormone (MCH), cocaine- and amphetamine-regulated transcript (CART) and neurotensin (NT). These neurons project widely throughout the brain to areas such as the locus coeruleus, the bed nucleus of the stria terminalis, the amygdala and the ventral tegmental area (VTA). Lateral hypothalamic projections to the VTA are believed to be important for driving behavior due to the involvement of dopaminergic reward circuitry. The purpose of this article is to review current knowledge regarding the lateral hypothalamic connections to the VTA and the role they play in driving these behaviors.
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Affiliation(s)
- Susan M Tyree
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
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19
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Genetically encoded indicators of neuronal activity. Nat Neurosci 2017; 19:1142-53. [PMID: 27571193 DOI: 10.1038/nn.4359] [Citation(s) in RCA: 392] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/14/2016] [Indexed: 02/07/2023]
Abstract
Experimental efforts to understand how the brain represents, stores and processes information require high-fidelity recordings of multiple different forms of neural activity within functional circuits. Thus, creating improved technologies for large-scale recordings of neural activity in the live brain is a crucial goal in neuroscience. Over the past two decades, the combination of optical microscopy and genetically encoded fluorescent indicators has become a widespread means of recording neural activity in nonmammalian and mammalian nervous systems, transforming brain research in the process. In this review, we describe and assess different classes of fluorescent protein indicators of neural activity. We first discuss general considerations in optical imaging and then present salient characteristics of representative indicators. Our focus is on how indicator characteristics relate to their use in living animals and on likely areas of future progress.
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20
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Iijima N, Miyamoto S, Matsumoto K, Takumi K, Ueta Y, Ozawa H. Development of an imaging system for in vivo real-time monitoring of neuronal activity in deep brain of free-moving rats. Histochem Cell Biol 2017; 148:289-298. [PMID: 28550404 DOI: 10.1007/s00418-017-1576-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2017] [Indexed: 12/31/2022]
Abstract
We have newly developed a system that allows monitoring of the intensity of fluorescent signals from deep brains of rats transgenically modified to express enhanced green fluorescent protein (eGFP) via an optical fiber. One terminal of the optical fiber was connected to a blue semiconductor laser oscillator/green fluorescence detector. The other terminal was inserted into the vicinity of the eGFP-expressing neurons. Since the optical fiber was vulnerable to twisting stresses caused by animal movement, we also developed a cage in which the floor automatically turns, in response to the turning of the rat's head. This relieved the twisting stress on the optical fiber. The system then enabled real-time monitoring of fluorescence in awake and unrestrained rats over many hours. Using this system, we could continuously monitor eGFP-expression in arginine vasopressin-eGFP transgenic rats. Moreover, we observed an increase of eGFP-expression in the paraventricular nucleus under salt-loading conditions. We then performed in vivo imaging of eGFP-expressing GnRH neurons in the hypothalamus, via a bundle consisting of 3000 thin optical fibers. With the combination of the optical fiber bundle connection to the fluorescence microscope, and the special cage system, we were able to capture and retain images of eGFP-expressing neurons from free-moving rats. We believe that our newly developed method for monitoring and imaging eGFP-expression in deep brain neurons will be useful for analysis of neuronal functions in awake and unrestrained animals for long durations.
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Affiliation(s)
- Norio Iijima
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan. .,Center for Medical Science, International University of Health and Welfare, 2600-1 Kitakanamaru, Ohtawara, 324-8501, Japan.
| | - Shinji Miyamoto
- Indeco Inc., 1-11-14 Kasuga, Bunkyo-ku, Tokyo, 112-0003, Japan.,Activelase, 3-5-22 Imai, Oume-si, Tokyo, Japan
| | - Keisuke Matsumoto
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Ken Takumi
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.,Department of Zoology, Okayama University of Science, 1-1 Ridai-cho, Okayama, 700-0005, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
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21
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Girven KS, Sparta DR. Probing Deep Brain Circuitry: New Advances in in Vivo Calcium Measurement Strategies. ACS Chem Neurosci 2017; 8:243-251. [PMID: 27984692 DOI: 10.1021/acschemneuro.6b00307] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The study of neuronal ensembles in awake and behaving animals is a critical question in contemporary neuroscience research. Through the examination of calcium fluctuations, which are correlated with neuronal activity, we are able to better understand complex neural circuits. Recently, the development of technologies including two-photon microscopy, miniature microscopes, and fiber photometry has allowed us to examine calcium activity in behaving subjects over time. Visualizing changes in intracellular calcium in vivo has been accomplished utilizing GCaMP, a genetically encoded calcium indicator. GCaMP allows researchers to tag cell-type specific neurons with engineered fluorescent proteins that alter their levels of fluorescence in response to changes in intracellular calcium concentration. Even with the evolution of GCaMP, in vivo calcium imaging had yet to overcome the limitation of light scattering, which occurs when imaging from neural tissue in deep brain regions. Currently, researchers have created in vivo methods to bypass this problem; this Review will delve into three of these state of the art techniques: (1) two-photon calcium imaging, (2) single photon calcium imaging, and (3) fiber photometry. Here we discuss the advantages and disadvantages of the three techniques. Continued advances in these imaging techniques will provide researchers with unparalleled access to the inner workings of the brain.
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Affiliation(s)
- Kasey S. Girven
- Department
of Anatomy and Neurobiology and ‡Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Dennis R. Sparta
- Department
of Anatomy and Neurobiology and ‡Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
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22
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Maia TV, Frank MJ. An Integrative Perspective on the Role of Dopamine in Schizophrenia. Biol Psychiatry 2017; 81:52-66. [PMID: 27452791 PMCID: PMC5486232 DOI: 10.1016/j.biopsych.2016.05.021] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/19/2016] [Accepted: 05/19/2016] [Indexed: 12/14/2022]
Abstract
We propose that schizophrenia involves a combination of decreased phasic dopamine responses for relevant stimuli and increased spontaneous phasic dopamine release. Using insights from computational reinforcement-learning models and basic-science studies of the dopamine system, we show that each of these two disturbances contributes to a specific symptom domain and explains a large set of experimental findings associated with that domain. Reduced phasic responses for relevant stimuli help to explain negative symptoms and provide a unified explanation for the following experimental findings in schizophrenia, most of which have been shown to correlate with negative symptoms: reduced learning from rewards; blunted activation of the ventral striatum, midbrain, and other limbic regions for rewards and positive prediction errors; blunted activation of the ventral striatum during reward anticipation; blunted autonomic responding for relevant stimuli; blunted neural activation for aversive outcomes and aversive prediction errors; reduced willingness to expend effort for rewards; and psychomotor slowing. Increased spontaneous phasic dopamine release helps to explain positive symptoms and provides a unified explanation for the following experimental findings in schizophrenia, most of which have been shown to correlate with positive symptoms: aberrant learning for neutral cues (assessed with behavioral and autonomic responses), and aberrant, increased activation of the ventral striatum, midbrain, and other limbic regions for neutral cues, neutral outcomes, and neutral prediction errors. Taken together, then, these two disturbances explain many findings in schizophrenia. We review evidence supporting their co-occurrence and consider their differential implications for the treatment of positive and negative symptoms.
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Affiliation(s)
- Tiago V Maia
- Institute for Molecular Medicine, School of Medicine, University of Lisbon, Lisbon, Portugal.
| | - Michael J Frank
- Department of Cognitive, Linguistic and Psychological Sciences, the Department of Psychiatry and Human Behavior, and the Brown Institute for Brain Science, Brown University, Providence, Rhode Island
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23
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Sanford CA, Soden ME, Baird MA, Miller SM, Schulkin J, Palmiter RD, Clark M, Zweifel LS. A Central Amygdala CRF Circuit Facilitates Learning about Weak Threats. Neuron 2016; 93:164-178. [PMID: 28017470 DOI: 10.1016/j.neuron.2016.11.034] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 08/25/2016] [Accepted: 11/11/2016] [Indexed: 01/08/2023]
Abstract
Fear is a graded central motive state ranging from mild to intense. As threat intensity increases, fear transitions from discriminative to generalized. The circuit mechanisms that process threats of different intensity are not well resolved. Here, we isolate a unique population of locally projecting neurons in the central nucleus of the amygdala (CeA) that produce the neuropeptide corticotropin-releasing factor (CRF). CRF-producing neurons and CRF in the CeA are required for discriminative fear, but both are dispensable for generalized fear at high US intensities. Consistent with a role in discriminative fear, CRF neurons undergo plasticity following threat conditioning and selectively respond to threat-predictive cues. We further show that excitability of genetically isolated CRF-receptive (CRFR1) neurons in the CeA is potently enhanced by CRF and that CRFR1 signaling in the CeA is critical for discriminative fear. These findings demonstrate a novel CRF gain-control circuit and show separable pathways for graded fear processing.
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Affiliation(s)
- Christina A Sanford
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - Marta E Soden
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - Madison A Baird
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - Samara M Miller
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA
| | - Jay Schulkin
- Department of Physiology and Biophysics, Georgetown University, Washington, DC 20057, USA; Department of Neuroscience, Georgetown University, Washington, DC 20057, USA; Department of Obstetrics and Gynecology, University of Washington, Seattle, WA 98105, USA
| | - Richard D Palmiter
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
| | - Michael Clark
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98105, USA
| | - Larry S Zweifel
- Department of Pharmacology, University of Washington, Seattle, WA 98105, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98105, USA.
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24
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Ablation of Type III Adenylyl Cyclase in Mice Causes Reduced Neuronal Activity, Altered Sleep Pattern, and Depression-like Phenotypes. Biol Psychiatry 2016; 80:836-848. [PMID: 26868444 PMCID: PMC5972377 DOI: 10.1016/j.biopsych.2015.12.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/02/2015] [Accepted: 12/03/2015] [Indexed: 01/02/2023]
Abstract
BACKGROUND Although major depressive disorder (MDD) has low heritability, a genome-wide association study in humans has recently implicated type 3 adenylyl cyclase (AC3; ADCY3) in MDD. Moreover, the expression level of AC3 in blood has been considered as a MDD biomarker in humans. Nevertheless, there is a lack of supporting evidence from animal studies. METHODS We employed multiple approaches to experimentally evaluate if AC3 is a contributing factor for major depression using mouse models lacking the Adcy3 gene. RESULTS We found that conventional AC3 knockout (KO) mice exhibited phenotypes associated with MDD in behavioral assays. Electroencephalography/electromyography recordings indicated that AC3 KO mice have altered sleep patterns characterized by increased percentage of rapid eye movement sleep. AC3 KO mice also exhibit neuronal atrophy. Furthermore, synaptic activity at cornu ammonis 3-cornu ammonis 1 synapses was significantly lower in AC3 KO mice, and they also exhibited attenuated long-term potentiation as well as deficits in spatial navigation. To confirm that these defects are not secondary responses to anosmia or developmental defects, we generated a conditional AC3 floxed mouse strain. This enabled us to inactivate AC3 function selectively in the forebrain and to inducibly ablate it in adult mice. Both AC3 forebrain-specific and AC3 inducible knockout mice exhibited prodepression phenotypes without anosmia. CONCLUSIONS This study demonstrates that loss of AC3 in mice leads to decreased neuronal activity, altered sleep pattern, and depression-like behaviors, providing strong evidence supporting AC3 as a contributing factor for MDD.
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25
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Lee JH, Lee S, Kim JH. Amygdala Circuits for Fear Memory: A Key Role for Dopamine Regulation. Neuroscientist 2016; 23:542-553. [DOI: 10.1177/1073858416679936] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In addition to modulating a number of cognitive functions including reward, punishment, motivation, and salience, dopamine (DA) plays a pivotal role in regulating threat-related emotional memory. Changes in neural circuits of the amygdala nuclei are also critically involved in the acquisition and expression of emotional memory. In this review, we summarize the regulation of amygdala circuits by DA. Specifically, we describe DA signaling in the amygdala, and DA regulation of synaptic transmission and synaptic plasticity of the amygdala neurons. Finally, we discuss a potential contribution of DA-related mechanisms to the pathogenesis of posttraumatic stress disorder.
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Affiliation(s)
- Joo Han Lee
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Korea
| | - Seungho Lee
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Korea
| | - Joung-Hun Kim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Korea
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26
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Xin W, Edwards N, Bonci A. VTA dopamine neuron plasticity - the unusual suspects. Eur J Neurosci 2016; 44:2975-2983. [PMID: 27711998 DOI: 10.1111/ejn.13425] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/26/2016] [Accepted: 10/03/2016] [Indexed: 12/25/2022]
Abstract
Dopamine neurons in the ventral tegmental area (VTA) are involved in a variety of physiological and pathological conditions, ranging from motivated behaviours to substance use disorders. While many studies have shown that these neurons can express plasticity at excitatory and inhibitory synapses, little is known about how inhibitory inputs and glial activity shape the output of DA neurons and therefore, merit greater discussion. In this review, we will attempt to fill in a bit more of the puzzle, with a focus on inhibitory transmission and astrocyte function. We summarize the findings within the VTA as well as observations made in other brain regions that have important implications for plasticity in general and should be considered in the context of DA neuron plasticity.
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Affiliation(s)
- Wendy Xin
- Synaptic Plasticity Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Nicholas Edwards
- Synaptic Plasticity Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Antonello Bonci
- Synaptic Plasticity Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
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27
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Dopamine and Its Actions in the Basal Ganglia System. INNOVATIONS IN COGNITIVE NEUROSCIENCE 2016. [DOI: 10.1007/978-3-319-42743-0_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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28
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Greenberg GD, Steinman MQ, Doig IE, Hao R, Trainor BC. Effects of social defeat on dopamine neurons in the ventral tegmental area in male and female California mice. Eur J Neurosci 2015; 42:3081-94. [PMID: 26469289 DOI: 10.1111/ejn.13099] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 12/11/2022]
Abstract
Dopamine neurons in the ventral tegmental area (VTA) have important functions related to rewards but are also activated in aversive contexts. Electrophysiology studies suggest that the degree to which VTA dopamine neurons respond to noxious stimuli is topographically organized across the dorsal-ventral extent. We used c-fos immunohistochemistry to examine the responses of VTA dopamine neurons in contexts of social defeat and social approach. Studying monogamous California mice (Peromyscus californicus) allowed us to observe the effects of social defeat on both males and females. Females exposed to three episodes of defeat, but not a single episode, had more tyrosine hydroxylase (TH)/c-fos-positive cells in the ventral (but not dorsal) VTA compared with controls. This observation suggests that repeated exposure to aversive contexts is necessary to trigger activation of VTA dopamine neurons. Defeat did not affect TH/c-fos colocalizations in males. We also examined the long-term effects of defeat on c-fos expression in a social interaction test. As previously reported, defeat reduced social interaction in females but not males. Surprisingly, there were no effects of defeat stress on TH/c-fos colocalizations in any subregion of the VTA. However, females had more TH/c-fos-positive cells than males across the entire VTA, and also had greater c-fos-positive cell counts in posterior subregions of the nucleus accumbens shell. Our results show that dopamine neurons in the VTA are more responsive to social contexts in females and that the ventral VTA in particular is sensitive to aversive contexts.
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Affiliation(s)
- Gian D Greenberg
- Neuroscience Graduate Group, University of California, Davis, CA, USA.,Department of Psychology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA.,Center for Neuroscience, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Michael Q Steinman
- Department of Psychology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA.,Molecular, Cellular and Integrative Physiology Graduate Group, University of California, Davis, CA, USA
| | - Ian E Doig
- Department of Psychology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Rebecca Hao
- Department of Psychology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Brian C Trainor
- Neuroscience Graduate Group, University of California, Davis, CA, USA.,Department of Psychology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA.,Center for Neuroscience, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
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29
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Jones GL, Soden ME, Knakal CR, Lee H, Chung AS, Merriam EB, Zweifel LS. A genetic link between discriminative fear coding by the lateral amygdala, dopamine, and fear generalization. eLife 2015; 4. [PMID: 26402461 PMCID: PMC4621744 DOI: 10.7554/elife.08969] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 09/23/2015] [Indexed: 01/01/2023] Open
Abstract
The lateral amygdala (LA) acquires differential coding of predictive and non-predictive fear stimuli that is critical for proper fear memory assignment. The neurotransmitter dopamine is an important modulator of LA activity and facilitates fear memory formation, but whether dopamine neurons aid in the establishment of discriminative fear coding by the LA is unknown. NMDA-type glutamate receptors in dopamine neurons are critical for the prevention of generalized fear following an aversive experience, suggesting a potential link between a cell autonomous function of NMDAR in dopamine neurons and fear coding by the LA. Here, we utilized mice with a selective genetic inactivation functional NMDARs in dopamine neurons (DAT-NR1 KO mice) combined with behavior, in vivo electrophysiology, and ex vivo electrophysiology in LA neurons to demonstrate that plasticity underlying differential fear coding in the LA is regulated by NMDAR signaling in dopamine neurons and alterations in this plasticity is associated non-discriminative cued-fear responses. DOI:http://dx.doi.org/10.7554/eLife.08969.001 When we experience a situation that causes us to feel fearful, the brain processes information about the events that led up to it. This information is encoded by groups of nerve cells called neurons in a region of the brain called the lateral amygdala. The nerve cells communicate with each other through chemicals called neurotransmitters. At a junction between two neurons—called a synapse—neurotransmitters are released from one cell and influence the activity of the other cell. Long-term changes in the strength of these communications in response to specific cues underlie the formation of memories about fearful events. When these changes occur incorrectly they can lead to memories about particular events becoming inaccurate, which can lead to fear being associated with related, but non-threatening, situations. This ‘generalization’ of fear can lead to generalized anxiety disorder and post-traumatic stress disorder. Dopamine is a neurotransmitter that plays an important role in forming memories of fearful events. However, it is not clear whether neurons that release dopamine are also involved in correctly discriminating fearful events from non-fearful ones. ‘Receptor’ proteins called NMDARs on the surface of neurons that release dopamine are critical for preventing generalized fear. These receptors detect another neurotransmitter called glutamate. Jones et al. used genetics and ‘electrophysiology’ techniques to study these receptors in mice. The experiments show that a gene that encodes part of an NMDAR in dopamine neurons plays a key role in how fear memories are formed. When this gene is selectively switched off in the dopamine neurons, mice are more likely to develop generalized fear and anxiety behaviors after a threatening experience. The experiments also demonstrate that these generalized threat responses are associated with differences in the way the synaptic connections in the lateral amygdala are strengthened. The next major challenge will be to find out which specific synaptic connections are strengthened and to establish how dopamine neuron activity patterns influences this connectivity. DOI:http://dx.doi.org/10.7554/eLife.08969.002
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Affiliation(s)
- Graham L Jones
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Marta E Soden
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Cerise R Knakal
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Heather Lee
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Amanda S Chung
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Elliott B Merriam
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
| | - Larry S Zweifel
- Department of Psychiatry and Behavioral Sciences and the Department of Pharmacology, University of Washington, Seattle, United States
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30
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Pignatelli M, Bonci A. Role of Dopamine Neurons in Reward and Aversion: A Synaptic Plasticity Perspective. Neuron 2015; 86:1145-57. [PMID: 26050034 DOI: 10.1016/j.neuron.2015.04.015] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The brain is wired to predict future outcomes. Experience-dependent plasticity at excitatory synapses within dopamine neurons of the ventral tegmental area, a key region for a broad range of motivated behaviors, is thought to be a fundamental cellular mechanism that enables adaptation to a dynamic environment. Thus, depending on the circumstances, dopamine neurons are capable of processing both positive and negative reinforcement learning strategies. In this review, we will discuss how changes in synaptic plasticity of dopamine neurons may affect dopamine release, as well as behavioral adaptations to different environmental conditions falling at opposite ends of a saliency spectrum ranging from reward to aversion.
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Affiliation(s)
- Marco Pignatelli
- Intramural Research Program, Synaptic Plasticity Section, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Antonello Bonci
- Intramural Research Program, Synaptic Plasticity Section, National Institute on Drug Abuse, Baltimore, MD 21224, USA; Solomon H. Snyder Neuroscience Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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