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Ziroldo JC, Torres LMB, Gamberini MT. Sugarcane (Saccharum officinarum L.) induces psychostimulant, anxiolytic-like effects and improvement of motor performance in rats. JOURNAL OF ETHNOPHARMACOLOGY 2024; 333:118476. [PMID: 38908491 DOI: 10.1016/j.jep.2024.118476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/03/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Sugarcane (Saccharum officinarum L.) is reported by traditional medicine as tonic, stimulating and beneficial in increasing resistance to fatigue. Previous preclinical studies in rats using aqueous extract of sugarcane leaves (AE) revealed pharmacological effects on the central nervous and cardiovascular systems involving the participation of dopaminergic pathways. This neurotransmission system is also related to motor, emotional and cognitive activities, which could, in part, justify the ethnopharmacological information. AIM OF STUDY The present study aimed to investigate the motor, emotional and cognitive activities of rats submitted to AE treatment using behavioral tests in order to correlate the pharmacological effects with the therapeutic benefits postulated by traditional medicine. Additionally, the chemical profile of AE was evaluated by HPLC-UV/Vis, and the presence of shikimic acid, vitexin, and ferulic acid, as possible chemical markers, was investigated through comparisons of chemical parameters with the authentic patterns, and a UV-Vis scan of known spectra. MATERIAL AND METHODS Rats received water (1.5 mL/kg, p.o.) and AE (0.5, 10 and 500 mg/kg, p.o.) in the absence and presence of haloperidol (0.5 mg/kg, i.p.), 90 min before open field; rotarod; elevated plus maze and inhibitory avoidance tests for investigation of motor; emotional and cognitive responses. As a positive control was used apomorphine (0.25 mg/kg, s.c.). The chemical profile of AE was evaluated by HPLC-UV/Vis and the presence of shikimic acid, vitexin and ferulic acid, as possible chemical markers, was investigated through comparisons with the retention times, an increase of the integral of the peak area determined by co-injection of AE with the authentic patterns, and a UV-Vis scan of known spectra. RESULTS In open field, it revealed that AE increased locomotion; reduced rearing but did not change freezing and grooming. Besides, AE increased motor performance in rotarod and reduced anxiety in elevated plus maze. A relation dose-response was observed in these tests where the lowest dose of AE was more effective in developing pharmacological responses. Previous administration of haloperidol inhibited the responses of AE. Inhibitory avoidance test revealed that AE did not modify fast-learning and associative memory. CONCLUSIONS Sugarcane induced psychostimulant, anxiolytic-like effects, and improvement of motor performance in rats, with the involvement of dopaminergic pathways. The present study points to AE as a potential adaptogen but, in addition to behavioral assessments, metabolic and molecular aspects, that involve the participation of a variety of regulatory systems, will be investigated in futures studies. Phytochemical analyses showed that AE is a complex matrix and revealed shikimic acid, vitexin, and ferulic acid as potential chemical markers.
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Affiliation(s)
- Juliana Corsini Ziroldo
- Department of Physiological Sciences, Santa Casa de Sao Paulo School of Medical Sciences - School of Medicine, São Paulo, SP, Brazil.
| | | | - Maria Thereza Gamberini
- Department of Physiological Sciences, Santa Casa de Sao Paulo School of Medical Sciences - School of Medicine, São Paulo, SP, Brazil.
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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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Plas SL, Tuna T, Bayer H, Juliano VAL, Sweck SO, Arellano Perez AD, Hassell JE, Maren S. Neural circuits for the adaptive regulation of fear and extinction memory. Front Behav Neurosci 2024; 18:1352797. [PMID: 38370858 PMCID: PMC10869525 DOI: 10.3389/fnbeh.2024.1352797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/15/2024] [Indexed: 02/20/2024] Open
Abstract
The regulation of fear memories is critical for adaptive behaviors and dysregulation of these processes is implicated in trauma- and stress-related disorders. Treatments for these disorders include pharmacological interventions as well as exposure-based therapies, which rely upon extinction learning. Considerable attention has been directed toward elucidating the neural mechanisms underlying fear and extinction learning. In this review, we will discuss historic discoveries and emerging evidence on the neural mechanisms of the adaptive regulation of fear and extinction memories. We will focus on neural circuits regulating the acquisition and extinction of Pavlovian fear conditioning in rodent models, particularly the role of the medial prefrontal cortex and hippocampus in the contextual control of extinguished fear memories. We will also consider new work revealing an important role for the thalamic nucleus reuniens in the modulation of prefrontal-hippocampal interactions in extinction learning and memory. Finally, we will explore the effects of stress on this circuit and the clinical implications of these findings.
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Affiliation(s)
- Samantha L. Plas
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
- Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Tuğçe Tuna
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
- Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Hugo Bayer
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
- Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Vitor A. L. Juliano
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Samantha O. Sweck
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
- Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Angel D. Arellano Perez
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
| | - James E. Hassell
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
| | - Stephen Maren
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, United States
- Institute for Neuroscience, Texas A&M University, College Station, TX, United States
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4
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McDonald AJ. Functional neuroanatomy of monoaminergic systems in the basolateral nuclear complex of the amygdala: Neuronal targets, receptors, and circuits. J Neurosci Res 2023; 101:1409-1432. [PMID: 37166098 PMCID: PMC10524224 DOI: 10.1002/jnr.25201] [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: 01/03/2023] [Revised: 03/03/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023]
Abstract
This review discusses neuroanatomical aspects of the three main monoaminergic systems innervating the basolateral nuclear complex (BNC) of the amygdala (serotonergic, noradrenergic, and dopaminergic systems). It mainly focuses on immunohistochemical (IHC) and in situ hybridization (ISH) studies that have analyzed the relationship of specific monoaminergic inputs and their receptors to specific neuronal subtypes in the BNC in order to better understand the anatomical substrates of the monoaminergic modulation of BNC circuitry. First, light and electron microscopic IHC investigations identifying the main BNC neuronal subpopulations and characterizing their local circuitry, including connections with discrete PN compartments and other INs, are reviewed. Then, the relationships of each of the three monoaminergic systems to distinct PN and IN cell types, are examined in detail. For each system, the neuronal targets and their receptor expression are discussed. In addition, pertinent electrophysiological investigations are discussed. The last section of the review compares and contrasts various aspects of each of the three monoaminergic systems. It is concluded that the large number of different receptors, each with a distinct mode of action, expressed by distinct cell types with different connections and functions, should offer innumerable ways to subtlety regulate the activity of the BNC by therapeutic drugs in psychiatric diseases in which there are alterations of BNC monoaminergic modulatory systems, such as in anxiety disorders, depression, and drug addiction. It is suggested that an important area for future studies is to investigate how the three systems interact in concert at the neuronal and neuronal network levels.
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Affiliation(s)
- Alexander Joseph McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
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5
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Ferrara NC, Opendak M. Amygdala circuit transitions supporting developmentally-appropriate social behavior. Neurobiol Learn Mem 2023; 201:107762. [PMID: 37116857 PMCID: PMC10204580 DOI: 10.1016/j.nlm.2023.107762] [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: 01/26/2023] [Revised: 03/30/2023] [Accepted: 04/22/2023] [Indexed: 04/30/2023]
Abstract
Social behaviors dynamically change throughout the lifespan alongside the maturation of neural circuits. The basolateral region of the amygdala (BLA), in particular, undergoes substantial maturational changes from birth throughout adolescence that are characterized by changes in excitation, inhibition, and dopaminergic modulation. In this review, we detail the trajectory through which BLA circuits mature and are influenced by dopaminergic systems to guide transitions in social behavior in infancy and adolescence using data from rodents. In early life, social behavior is oriented towards approaching the attachment figure, with minimal BLA involvement. Around weaning age, dopaminergic innervation of the BLA introduces avoidance of novel peers into rat pups' behavioral repertoire. In adolescence, social behavior transitions towards peer-peer interactions with a high incidence of social play-related behaviors. This transition coincides with an increasing role of the BLA in the regulation of social behavior. Adolescent BLA maturation can be characterized by an increasing integration and function of local inhibitory GABAergic circuits and their engagement by the medial prefrontal cortex (mPFC). Manipulation of these transitions using viral circuit dissection techniques and early adversity paradigms reveals the sensitivity of this system and its role in producing age-appropriate social behavior.
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Affiliation(s)
- Nicole C Ferrara
- Discipline of Physiology and Biophysics, Department of Foundational Sciences and Humanities, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA; Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Maya Opendak
- Kennedy Krieger Institute, Baltimore, MD, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Johns Hopkins Kavli Neuroscience Discovery Institute, Baltimore, MD, USA.
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6
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Moghaddam B, Abbas AI. Depression and Prefrontal Cortex: All Roads Lead to Dopamine. Biol Psychiatry 2022; 91:773-774. [PMID: 35422235 DOI: 10.1016/j.biopsych.2022.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 11/17/2022]
Affiliation(s)
- Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon; Department of Psychiatry, Oregon Health and Science University, Portland, Oregon.
| | - Atheir I Abbas
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon; Department of Psychiatry, Oregon Health and Science University, Portland, Oregon; VA Portland Health Care System, Portland, Oregon
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7
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Aksoy-Aksel A, Gall A, Seewald A, Ferraguti F, Ehrlich I. Midbrain dopaminergic inputs gate amygdala intercalated cell clusters by distinct and cooperative mechanisms in male mice. eLife 2021; 10:e63708. [PMID: 34028352 PMCID: PMC8143799 DOI: 10.7554/elife.63708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 05/06/2021] [Indexed: 01/04/2023] Open
Abstract
Dopaminergic signaling plays an important role in associative learning, including fear and extinction learning. Dopaminergic midbrain neurons encode prediction error-like signals when threats differ from expectations. Within the amygdala, GABAergic intercalated cell (ITC) clusters receive one of the densest dopaminergic projections, but their physiological consequences are incompletely understood. ITCs are important for fear extinction, a function thought to be supported by activation of ventromedial ITCs that inhibit central amygdala fear output. In mice, we reveal two distinct novel mechanisms by which mesencephalic dopaminergic afferents control ITCs. Firstly, they co-release GABA to mediate rapid, direct inhibition. Secondly, dopamine suppresses inhibitory interactions between distinct ITC clusters via presynaptic D1 receptors. Early extinction training augments both GABA co-release onto dorsomedial ITCs and dopamine-mediated suppression of dorso- to ventromedial inhibition between ITC clusters. These findings provide novel insights into dopaminergic mechanisms shaping the activity balance between distinct ITC clusters that could support their opposing roles in fear behavior.
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Affiliation(s)
- Ayla Aksoy-Aksel
- Hertie Institute for Clinical Brain ResearchTübingenGermany
- Centre for Integrative NeuroscienceTübingenGermany
- Department of Neurobiology, Institute of Biomaterials and Biomolecular Systems, University of StuttgartStuttgartGermany
| | - Andrea Gall
- Hertie Institute for Clinical Brain ResearchTübingenGermany
- Centre for Integrative NeuroscienceTübingenGermany
- Department of Neurobiology, Institute of Biomaterials and Biomolecular Systems, University of StuttgartStuttgartGermany
| | - Anna Seewald
- Department of Pharmacology, Medical University of InnsbruckInnsbruckAustria
| | | | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain ResearchTübingenGermany
- Centre for Integrative NeuroscienceTübingenGermany
- Department of Neurobiology, Institute of Biomaterials and Biomolecular Systems, University of StuttgartStuttgartGermany
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8
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Khlghatyan J, Quintana C, Parent M, Beaulieu JM. High Sensitivity Mapping of Cortical Dopamine D2 Receptor Expressing Neurons. Cereb Cortex 2020; 29:3813-3827. [PMID: 30295716 DOI: 10.1093/cercor/bhy261] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 02/07/2023] Open
Abstract
Cortical D2 dopamine receptor (Drd2) have mostly been examined in the context of cognitive function regulation and neurotransmission modulation of medial prefrontal cortex by principal neurons and parvalbumin positive, fast-spiking, interneurons in schizophrenia. Early studies suggested the presence of D2 receptors in several cortical areas, albeit with major technical limitations. We used combinations of transgenic reporter systems, recombinase activated viral vectors, quantitative translatome analysis, and high sensitivity in situ hybridization to identify D2 receptor expressing cells and establish a map of their respective projections. Our results identified previously uncharacterized clusters of D2 expressing neurons in limbic and sensory regions of the adult mouse brain cortex. Characterization of these clusters by translatome analysis and cell type specific labeling revealed highly heterogeneous expression of D2 receptors in principal neurons and various populations of interneurons across cortical areas. Transcript enrichment analysis also demonstrated variable levels of D2 receptor expression and several orphan G-protein-coupled receptors coexpression in different neuronal clusters, thus suggesting strategies for genetic and therapeutic targeting of D2 expressing neurons in specific cortical areas. These results pave the way for a thorough re-examination of cortical D2 receptor functions, which could provide information about neuronal circuits involved in psychotic and mood disorders.
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Affiliation(s)
- Jivan Khlghatyan
- Department of Pharmacology & Toxicology, University of Toronto, Medical Sciences Building, Toronto, Ontario, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec-City, Quebec, Canada
| | - Clémentine Quintana
- Department of Pharmacology & Toxicology, University of Toronto, Medical Sciences Building, Toronto, Ontario, Canada
| | - Martin Parent
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec-City, Quebec, Canada
| | - Jean-Martin Beaulieu
- Department of Pharmacology & Toxicology, University of Toronto, Medical Sciences Building, Toronto, Ontario, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec-City, Quebec, Canada
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9
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Quintana C, Beaulieu JM. A fresh look at cortical dopamine D2 receptor expressing neurons. Pharmacol Res 2018; 139:440-445. [PMID: 30528973 DOI: 10.1016/j.phrs.2018.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/28/2018] [Accepted: 12/03/2018] [Indexed: 01/02/2023]
Abstract
The dopamine D2 receptor (DRD2) remains the principal target of antipsychotic drugs used for the management of schizophrenia and other psychotic disorders. This receptor is highly expressed within the basal ganglia, more specifically the striatal caudate nucleus and the nucleus accumbens. The general functions, signaling and behavioral contributions of striatal DRD2 are well understood. However, the study of cortical DRD2 expression and functions has for the most part been restricted to a subset of pyramidal neurons and interneurons (e.g. parvalbumine positive) of the pre frontal cortex where DRD2 regulated local circuits are believed to contribute to the regulation of emotional and cognitive functions. The further investigations of cortical DRD2 functions have been hindered by relatively low receptor expression and the sensitivity of detection methods. Here we report recent findings by our group using high sensitivity approaches to map cortical DRD2 expression. Results from these investigations revealed different scales of heterogeneity within DRD2 expressing neurons. These variations affected the types of neurons expressing DRD2 as well as the co-expression of DRD2 with other receptors across several cortical regions. Furthermore several cortical regions showing higher clusters of DRD2 expressing neurons are involved in the regulation of emotional, cognitive and sensory functions that can be involved in the expression of psychotic symptoms. These findings underscore the need for a reexamination of cortical DRD2 mediated synaptic plasticity in the context of schizophrenia and other psychotic disorders.
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Affiliation(s)
- Clémentine Quintana
- Department of Pharmacology & Toxicology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S 1A8, Canada
| | - Jean-Martin Beaulieu
- Department of Pharmacology & Toxicology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S 1A8, Canada.
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10
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Weele CMV, Siciliano CA, Tye KM. Dopamine tunes prefrontal outputs to orchestrate aversive processing. Brain Res 2018; 1713:16-31. [PMID: 30513287 DOI: 10.1016/j.brainres.2018.11.044] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/25/2018] [Accepted: 11/30/2018] [Indexed: 01/06/2023]
Abstract
Decades of research suggest that the mesocortical dopamine system exerts powerful control over mPFC physiology and function. Indeed, dopamine signaling in the medial prefrontal cortex (mPFC) is implicated in a vast array of processes, including working memory, stimulus discrimination, stress responses, and emotional and behavioral control. Consequently, even slight perturbations within this delicate system result in profound disruptions of mPFC-mediated processes. Many neuropsychiatric disorders are associated with dysregulation of mesocortical dopamine, including schizophrenia, depression, attention deficit hyperactivity disorder, post-traumatic stress disorder, among others. Here, we review the anatomy and functions of the mesocortical dopamine system. In contrast to the canonical role of striatal dopamine in reward-related functions, recent work has revealed that mesocortical dopamine fine-tunes distinct efferent projection populations in a manner that biases subsequent behavior towards responding to stimuli associated with potentially aversive outcomes. We propose a framework wherein dopamine can serve as a signal for switching mPFC states by orchestrating how information is routed to the rest of the brain.
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Affiliation(s)
- Caitlin M Vander Weele
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Cody A Siciliano
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kay M Tye
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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11
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Jie F, Yin G, Yang W, Yang M, Gao S, Lv J, Li B. Stress in Regulation of GABA Amygdala System and Relevance to Neuropsychiatric Diseases. Front Neurosci 2018; 12:562. [PMID: 30154693 PMCID: PMC6103381 DOI: 10.3389/fnins.2018.00562] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 07/25/2018] [Indexed: 01/19/2023] Open
Abstract
The amygdala is an almond-shaped nucleus located deep and medially within the temporal lobe and is thought to play a crucial role in the regulation of emotional processes. GABAergic neurotransmission inhibits the amygdala and prevents us from generating inappropriate emotional and behavioral responses. Stress may cause the reduction of the GABAergic interneuronal network and the development of neuropsychological diseases. In this review, we summarize the recent evidence investigating the possible mechanisms underlying GABAergic control of the amygdala and its interaction with acute and chronic stress. Taken together, this study may contribute to future progress in finding new approaches to reverse the attenuation of GABAergic neurotransmission induced by stress in the amygdala.
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Affiliation(s)
- Fan Jie
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Guanghao Yin
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Wei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Modi Yang
- Department of Gastrointestinal Colorectal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Shuohui Gao
- Department of Gastrointestinal Colorectal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Jiayin Lv
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
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12
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Absence of fear renewal and functional connections between prefrontal cortex and hippocampus in infant mice. Neurobiol Learn Mem 2018; 152:1-9. [DOI: 10.1016/j.nlm.2018.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 03/31/2018] [Accepted: 04/18/2018] [Indexed: 11/21/2022]
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13
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Song J, Chen M, Dong Y, Lai B, Zheng P. Chronic morphine selectively sensitizes the effect of D1 receptor agonist on presynaptic glutamate release in basolateral amygdala neurons that project to prelimbic cortex. Neuropharmacology 2018; 133:375-384. [DOI: 10.1016/j.neuropharm.2018.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/18/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
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Abstract
The activity of neural circuits that underpin particular behaviours are one of the most interesting questions in neurobiology today. This understanding will not only lead to a detailed understanding of learning and memory formation, but also provides a platform for the development of novel therapeutic approaches to a range of neurological disorders that afflict humans. Among the different behavioural paradigms, Pavlovian fear conditioning and its extinction are two of the most extensively used to study acquisition, consolidation and retrieval of fear-related memories. The amygdala, medial prefrontal cortex (mPFC) and hippocampus are three regions with extensive bidirectional connections, and play key roles in fear processing. In this chapter, we summarise our current understanding of the structure and physiological role of these three regions in fear learning and extinction.
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Affiliation(s)
- Roger Marek
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
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Madsen HB, Guerin AA, Kim JH. Investigating the role of dopamine receptor- and parvalbumin-expressing cells in extinction of conditioned fear. Neurobiol Learn Mem 2017; 145:7-17. [DOI: 10.1016/j.nlm.2017.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/09/2017] [Accepted: 08/21/2017] [Indexed: 12/16/2022]
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16
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Zhang T, Chen T, Chen P, Zhang B, Hong J, Chen L. MPTP-Induced Dopamine Depletion in Basolateral Amygdala via Decrease of D2R Activation Suppresses GABA A Receptors Expression and LTD Induction Leading to Anxiety-Like Behaviors. Front Mol Neurosci 2017; 10:247. [PMID: 28824377 PMCID: PMC5545577 DOI: 10.3389/fnmol.2017.00247] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/24/2017] [Indexed: 11/13/2022] Open
Abstract
Anxiety disorders commonly occur in Parkinson’s disease. Using field potential recording and patch-clamp recording, we evaluated influence of MPTP-reduced dopaminergic afferent in basolateral amygdala (BLA), a main region for affective regulation, on excitatory–inhibitory circuits and synaptic plasticity. Field excitatory post-synaptic potential (fEPSP) slopes at external capsule-BLA synapses were increased in MPTP-mice with decreases in paired-pulse facilitation and long-term potentiation amplitude, which were corrected by bath-application of D2R agonist quinpirole or cannabinoid type 1 receptors agonist WIN55,212-2, but not D1R agonist SKF38393. Compared to single waveform fEPSP in control mice, a multi-spike waveform fEPSP was observed in MPTP-mice with prolongation of duration and an increase in paired-pulse inhibition, which were recovered by BLA-injection of quinpirole for 2 days rather than bath-application. Density of GABA-evoked current (IGABA) in BLA principal neurons and GABAAR-α2 subunit expression were reduced in MPTP-mice, which were recovered by administration of quinpirole. Decline of PKC phosphorylation in BLA of MPTP-mice was corrected by bath-application of quinpirole, but not SKF38393. In MPTP-mice, BLA-injection of quinpirole or PKC activator PMA could recover GABAAR expression, which was sensitive to PKC inhibitor GF109203X. The impairment of long-term depression (LTD) in MPTP-mice was rescued by bath-application of GABAAR agonist muscimol or BLA-injection of quinpirole and PMA. Finally, BLA-injection of muscimol, quinpirole or PMA relieved anxiety-like behaviors in MPTP-mice. The results indicate that the MPTP-induced dopamine depletion in BLA principal neurons through reducing D2R-mediated PKC phosphorylation suppresses GABAAR expression and activity, which impairs GABAAR-mediated inhibition and LTD induction leading to anxiety-like behaviors.
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Affiliation(s)
- Tingting Zhang
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Tingting Chen
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Peipei Chen
- Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Baofeng Zhang
- Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Juan Hong
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Ling Chen
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
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17
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Effects of Blockade of D1 and D2 Receptors in the Basolateral Amygdala on the Behavior of Rats with High and Low Levels of Anxiety and Fear. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s11055-016-0352-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Gasser PJ, Hurley MM, Chan J, Pickel VM. Organic cation transporter 3 (OCT3) is localized to intracellular and surface membranes in select glial and neuronal cells within the basolateral amygdaloid complex of both rats and mice. Brain Struct Funct 2016; 222:1913-1928. [PMID: 27659446 DOI: 10.1007/s00429-016-1315-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/16/2016] [Indexed: 10/21/2022]
Abstract
Organic cation transporter 3 (OCT3) is a high-capacity, low-affinity transporter that mediates corticosterone-sensitive uptake of monoamines including norepinephrine, epinephrine, dopamine, histamine and serotonin. OCT3 is expressed widely throughout the amygdaloid complex and other brain regions where monoamines are key regulators of emotional behaviors affected by stress. However, assessing the contribution of OCT3 to the regulation of monoaminergic neurotransmission and monoamine-dependent regulation of behavior requires fundamental information about the subcellular distribution of OCT3 expression. We used immunofluorescence and immuno-electron microscopy to examine the cellular and subcellular distribution of the transporter in the basolateral amygdaloid complex of the rat and mouse brain. OCT3-immunoreactivity was observed in both glial and neuronal perikarya in both rat and mouse amygdala. Electron microscopic immunolabeling revealed plasma membrane-associated OCT3 immunoreactivity on axonal, dendritic, and astrocytic processes adjacent to a variety of synapses, as well as on neuronal somata. In addition to plasma membrane sites, OCT3 immunolabeling was also observed associated with neuronal and glial endomembranes, including Golgi, mitochondrial and nuclear membranes. Particularly prominent labeling of the outer nuclear membrane was observed in neuronal, astrocytic, microglial and endothelial perikarya. The localization of OCT3 to neuronal and glial plasma membranes adjacent to synaptic sites is consistent with an important role for this transporter in regulating the amplitude, duration, and physical spread of released monoamines, while its localization to mitochondrial and outer nuclear membranes suggests previously undescribed roles for the transporter in the intracellular disposition of monoamines.
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Affiliation(s)
- Paul J Gasser
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53201-1881, USA.
| | - Matthew M Hurley
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53201-1881, USA
| | - June Chan
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY, 10065, USA
| | - Virginia M Pickel
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY, 10065, USA
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19
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Yan R, Fan Q, Zhou J, Vassar R. Inhibiting BACE1 to reverse synaptic dysfunctions in Alzheimer's disease. Neurosci Biobehav Rev 2016; 65:326-40. [PMID: 27044452 PMCID: PMC4856578 DOI: 10.1016/j.neubiorev.2016.03.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/25/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022]
Abstract
Over the past two decades, many studies have identified significant contributions of toxic β-amyloid peptides (Aβ) to the etiology of Alzheimer's disease (AD), which is the most common age-dependent neurodegenerative disease. AD is also recognized as a disease of synaptic failure. Aβ, generated by sequential proteolytic cleavages of amyloid precursor protein (APP) by BACE1 and γ-secretase, is one of major culprits that cause this failure. In this review, we summarize current findings on how BACE1-cleaved APP products impact learning and memory through proteins localized on glutamatergic, GABAergic, and dopaminergic synapses. Considering the broad effects of Aβ on all three types of synapses, BACE1 inhibition emerges as a practical approach for ameliorating Aβ-mediated synaptic dysfunctions. Since BACE1 inhibitory drugs are currently in clinical trials, this review also discusses potential complications arising from BACE1 inhibition. We emphasize that the benefits of BACE1 inhibitory drugs will outweigh the concerns.
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Affiliation(s)
- Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - John Zhou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Robert Vassar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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20
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Zikopoulos B, John YJ, García-Cabezas MÁ, Bunce JG, Barbas H. The intercalated nuclear complex of the primate amygdala. Neuroscience 2016; 330:267-90. [PMID: 27256508 DOI: 10.1016/j.neuroscience.2016.05.052] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/09/2016] [Accepted: 05/26/2016] [Indexed: 12/20/2022]
Abstract
The organization of the inhibitory intercalated cell masses (IM) of the primate amygdala is largely unknown despite their key role in emotional processes. We studied the structural, topographic, neurochemical and intrinsic connectional features of IM neurons in the rhesus monkey brain. We found that the intercalated neurons are not confined to discrete cell clusters, but form a neuronal net that is interposed between the basal nuclei and extends to the dorsally located anterior, central, and medial nuclei of the amygdala. Unlike the IM in rodents, which are prominent in the anterior half of the amygdala, the primate inhibitory net stretched throughout the antero-posterior axis of the amygdala, and was most prominent in the central and posterior extent of the amygdala. There were two morphologic types of intercalated neurons: spiny and aspiny. Spiny neurons were the most abundant; their somata were small or medium size, round or elongated, and their dendritic trees were round or bipolar, depending on location. The aspiny neurons were on average slightly larger and had varicose dendrites with no spines. There were three non-overlapping neurochemical populations of IM neurons, in descending order of abundance: (1) Spiny neurons that were positive for the striatal associated dopamine- and cAMP-regulated phosphoprotein (DARPP-32+); (2) Aspiny neurons that expressed the calcium-binding protein calbindin (CB+); and (3) Aspiny neurons that expressed nitric oxide synthase (NOS+). The unique combinations of structural and neurochemical features of the three classes of IM neurons suggest different physiological properties and function. The three types of IM neurons were intermingled and likely interconnected in distinct ways, and were innervated by intrinsic neurons within the amygdala, or by external sources, in pathways that underlie fear conditioning and anxiety.
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Affiliation(s)
- Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States; Graduate Program for Neuroscience, Boston University and School of Medicine, Boston, MA, United States.
| | - Yohan J John
- Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
| | | | - Jamie G Bunce
- Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
| | - Helen Barbas
- Graduate Program for Neuroscience, Boston University and School of Medicine, Boston, MA, United States; Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
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21
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Zhang J, McDonald AJ. Light and electron microscopic analysis of enkephalin-like immunoreactivity in the basolateral amygdala, including evidence for convergence of enkephalin-containing axon terminals and norepinephrine transporter-containing axon terminals onto common targets. Brain Res 2016; 1636:62-73. [PMID: 26835559 DOI: 10.1016/j.brainres.2016.01.045] [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] [Received: 12/04/2015] [Revised: 01/20/2016] [Accepted: 01/25/2016] [Indexed: 12/21/2022]
Abstract
Modulatory interactions of opioids and norepinephrine (NE) in the anterior subdivision of the basolateral nucleus of the amygdala (BLa) are critical for the consolidation of memories of emotionally arousing experiences. Although there have been several studies of the noradrenergic system in the amygdalar basolateral nuclear complex (BLC), little is known about the chemical neuroanatomy of opioid systems in this region. To address this knowledge gap the present study first examined the distribution of met-enkephalin-like immunoreactivity (ENK-ir) in the BLC at the light microscopic level, and then utilized dual-labeling immunocytochemistry combined with electron microscopy to investigate the extent of convergence of NE and ENK terminals onto common structures in the BLa. Antibodies to ENK and the norepinephrine transporter (NET) were used in these studies. Light microscopic examination revealed that a subpopulation of small nonpyramidal neurons expressed ENK-ir in all nuclei of the BLC. In addition, the somata of some pyramidal cells exhibited light to moderate ENK-ir. ENK+ axon terminals were also observed. Ultrastructural analysis confined to the BLa revealed that most ENK+ axon terminals formed asymmetrical synapses that mainly contacted spines and shafts of thin dendrites. ENK+ terminals forming symmetrical synapses mainly contacted dendritic shafts. Approximately 20% of NET+ terminals contacted a structure that was also contacted by an ENK+ terminal and 6% of NET+ terminals contacted an ENK+ terminal. These findings suggest that ENK and NE terminals in the BLa may interact by targeting common dendrites and by direct interactions between the two types of terminals.
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Affiliation(s)
- Jingyi Zhang
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, United States
| | - Alexander J McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, United States.
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22
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Giustino TF, Maren S. The Role of the Medial Prefrontal Cortex in the Conditioning and Extinction of Fear. Front Behav Neurosci 2015; 9:298. [PMID: 26617500 PMCID: PMC4637424 DOI: 10.3389/fnbeh.2015.00298] [Citation(s) in RCA: 336] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 10/26/2015] [Indexed: 12/18/2022] Open
Abstract
Once acquired, a fearful memory can persist for a lifetime. Although learned fear can be extinguished, extinction memories are fragile. The resilience of fear memories to extinction may contribute to the maintenance of disorders of fear and anxiety, including post-traumatic stress disorder (PTSD). As such, considerable effort has been placed on understanding the neural circuitry underlying the acquisition, expression, and extinction of emotional memories in rodent models as well as in humans. A triad of brain regions, including the prefrontal cortex, hippocampus, and amygdala, form an essential brain circuit involved in fear conditioning and extinction. Within this circuit, the prefrontal cortex is thought to exert top-down control over subcortical structures to regulate appropriate behavioral responses. Importantly, a division of labor has been proposed in which the prelimbic (PL) and infralimbic (IL) subdivisions of the medial prefrontal cortex (mPFC) regulate the expression and suppression of fear in rodents, respectively. Here, we critically review the anatomical and physiological evidence that has led to this proposed dichotomy of function within mPFC. We propose that under some conditions, the PL and IL act in concert, exhibiting similar patterns of neural activity in response to aversive conditioned stimuli and during the expression or inhibition of conditioned fear. This may stem from common synaptic inputs, parallel downstream outputs, or cortico-cortical interactions. Despite this functional covariation, these mPFC subdivisions may still be coding for largely opposing behavioral outcomes, with PL biased towards fear expression and IL towards suppression.
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Affiliation(s)
- Thomas F Giustino
- Department of Psychology and Institute for Neuroscience, Texas A&M University College Station, TX, USA
| | - Stephen Maren
- Department of Psychology and Institute for Neuroscience, Texas A&M University College Station, TX, USA
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23
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Perusini JN, Fanselow MS. Neurobehavioral perspectives on the distinction between fear and anxiety. ACTA ACUST UNITED AC 2015; 22:417-25. [PMID: 26286652 PMCID: PMC4561408 DOI: 10.1101/lm.039180.115] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/09/2015] [Indexed: 01/17/2023]
Abstract
In this review, we discuss the usefulness of the distinction between fear and anxiety. The clinical use of the labels is ambiguous, often defining one in terms of the other. We first consider what a useful, objective, and scientifically valid definition would entail and then evaluate several fear/anxiety distinctions that have been made in the neurobiological literature. A strong distinction should specify the difference in conditions that lead to fear versus anxiety. Additionally, fear and anxiety should generate distinct sets of behaviors. Ideally, the two states should be supported by distinguishable neuroanatomical circuits. Such a conceptualization would be consistent with the National Institute of Mental Health's Research Domain Criteria (RDoc). The majority of neurobiological approaches to the fear versus anxiety distinction fail to differentiate the two states in terms of behavior, often using the exact same behavioral measures as indicators. Of the two that do, only Predatory Imminence Theory provides a distinction both in terms of cause and effect. Indeed, that approach provides a ready distinction of anxiety, fear, and panic in terms of both antecedent conditions and response selection rules. Additionally, it appeals to distinct neural circuits to generate these modes of action.
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Affiliation(s)
- Jennifer N Perusini
- Department of Psychiatry, Columbia University, New York, New York 10032, USA Division of Integrative Neuroscience, New York State Psychiatric Institute (NYSPI)/Research Foundation for Mental Hygiene, Inc. (RFMH), New York, New York 10032, USA
| | - Michael S Fanselow
- Department of Psychology, University of California at Los Angeles, Los Angeles, California 90095, USA Department of Psychiatry and Biobehavioral Sciences, University of California at Los Angeles, Los Angeles, California 90095, USA
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24
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Barbas H. General Cortical and Special Prefrontal Connections: Principles from Structure to Function. Annu Rev Neurosci 2015; 38:269-89. [DOI: 10.1146/annurev-neuro-071714-033936] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Helen Barbas
- Neural Systems Laboratory, Department of Health Sciences; Graduate Program in Neuroscience; School of Medicine; Boston University, Boston, Massachusetts 02215;
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25
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Strobel C, Marek R, Gooch HM, Sullivan RKP, Sah P. Prefrontal and Auditory Input to Intercalated Neurons of the Amygdala. Cell Rep 2015; 10:1435-1442. [PMID: 25753409 DOI: 10.1016/j.celrep.2015.02.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/17/2015] [Accepted: 01/29/2015] [Indexed: 01/12/2023] Open
Abstract
The basolateral amygdala (BLA) and prefrontal cortex (PFC) are partners in fear learning and extinction. Intercalated (ITC) cells are inhibitory neurons that surround the BLA. Lateral ITC (lITC) neurons provide feed-forward inhibition to BLA principal neurons, whereas medial ITC (mITC) neurons form an inhibitory interface between the BLA and central amygdala (CeA). Notably, infralimbic prefrontal (IL) input to mITC neurons is thought to play a key role in fear extinction. Here, using targeted optogenetic stimulation, we show that lITC neurons receive auditory input from cortical and thalamic regions. IL inputs innervate principal neurons in the BLA but not mITC neurons. These results suggest that (1) these neurons may play a more central role in fear learning as both lITCs and mITCs receive auditory input and that (2) mITC neurons cannot be driven directly by the IL, and their role in fear extinction is likely mediated via the BLA.
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Affiliation(s)
- Cornelia Strobel
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Roger Marek
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Helen M Gooch
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert K P Sullivan
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pankaj Sah
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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26
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GABAergic somatostatin-immunoreactive neurons in the amygdala project to the entorhinal cortex. Neuroscience 2015; 290:227-42. [PMID: 25637800 DOI: 10.1016/j.neuroscience.2015.01.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/14/2015] [Accepted: 01/16/2015] [Indexed: 11/21/2022]
Abstract
The entorhinal cortex and other hippocampal and parahippocampal cortices are interconnected by a small number of GABAergic nonpyramidal neurons in addition to glutamatergic pyramidal cells. Since the cortical and basolateral amygdalar nuclei have cortex-like cell types and have robust projections to the entorhinal cortex, we hypothesized that a small number of amygdalar GABAergic nonpyramidal neurons might participate in amygdalo-entorhinal projections. To test this hypothesis we combined Fluorogold (FG) retrograde tract tracing with immunohistochemistry for the amygdalar nonpyramidal cell markers glutamic acid decarboxylase (GAD), parvalbumin (PV), somatostatin (SOM), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and the m2 muscarinic cholinergic receptor (M2R). Injections of FG into the rat entorhinal cortex labeled numerous neurons that were mainly located in the cortical and basolateral nuclei of the amygdala. Although most of these amygdalar FG+ neurons labeled by entorhinal injections were large pyramidal cells, 1-5% were smaller long-range nonpyramidal neurons (LRNP neurons) that expressed SOM, or both SOM and NPY. No amygdalar FG+ neurons in these cases were PV+ or VIP+. Cell counts revealed that LRNP neurons labeled by injections into the entorhinal cortex constituted about 10-20% of the total SOM+ population, and 20-40% of the total NPY population in portions of the lateral amygdalar nucleus that exhibited a high density of FG+ neurons. Sixty-two percent of amygdalar FG+/SOM+ neurons were GAD+, and 51% were M2R+. Since GABAergic projection neurons typically have low perikaryal levels of GABAergic markers, it is actually possible that most or all of the amygdalar LRNP neurons are GABAergic. Like GABAergic LRNP neurons in hippocampal/parahippocampal regions, amygdalar LRNP neurons that project to the entorhinal cortex are most likely involved in synchronizing oscillatory activity between the two regions. These oscillations could entrain synchronous firing of amygdalar and entorhinal pyramidal neurons, thus facilitating functional interactions between them, including synaptic plasticity.
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27
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Abstract
Lines of evidence coming from many branches of neuroscience indicate that anxiety disorders arise from a dysfunction in the modulation of brain circuits which regulate emotional responses to potentially threatening stimuli. The concept of anxiety disorders as a disturbance of emotional response regulation is a useful one as it allows anxiety to be explained in terms of a more general model of aberrant salience and also because it identifies avenues for developing psychological, behavioral, and pharmacological strategies for the treatment of anxiety disorder. These circuits involve bottom-up activity from the amygdala, indicating the presence of potentially threatening stimuli, and top-down control mechanisms originating in the prefrontal cortex, signaling the emotional salience of stimuli. Understanding the factors that control cortical mechanisms may open the way to identification of more effective cognitive behavioral strategies for managing anxiety disorders. The brain circuits in the amygdala are thought to comprise inhibitory networks of γ-aminobutyric acid-ergic (GABAergic) interneurons and this neurotransmitter thus plays a key role in the modulation of anxiety responses both in the normal and pathological state. The presence of allosteric sites on the GABAA receptor allows the level of inhibition of neurons in the amygdala to be regulated with exquisite precision, and these sites are the molecular targets of the principal classes of anxiolytic drugs. Changes in the levels of endogenous modulators of these allosteric sites as well as changes in the subunit composition of the GABAA receptor may represent mechanisms whereby the level of neuronal inhibition is downregulated in pathological anxiety states. Neurosteroids are synthesized in the brain and act as allosteric modulators of the GABAA receptor. Since their synthesis is itself regulated by stress and by anxiogenic stimuli, targeting the neurosteroid-GABAA receptor axis represents an attractive target for the modulation of anxiety.
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Affiliation(s)
- Philippe Nuss
- Department of Psychiatry, Hôpital St Antoine, AP-HP, Paris, France ; UMR 7203, INSERM ERL 1057 - Bioactive Molecules Laboratory, Pierre and Marie Curie University, Paris, France
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28
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Singewald N, Schmuckermair C, Whittle N, Holmes A, Ressler KJ. Pharmacology of cognitive enhancers for exposure-based therapy of fear, anxiety and trauma-related disorders. Pharmacol Ther 2014; 149:150-90. [PMID: 25550231 PMCID: PMC4380664 DOI: 10.1016/j.pharmthera.2014.12.004] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 12/24/2014] [Indexed: 12/20/2022]
Abstract
Pathological fear and anxiety are highly debilitating and, despite considerable advances in psychotherapy and pharmacotherapy they remain insufficiently treated in many patients with PTSD, phobias, panic and other anxiety disorders. Increasing preclinical and clinical evidence indicates that pharmacological treatments including cognitive enhancers, when given as adjuncts to psychotherapeutic approaches [cognitive behavioral therapy including extinction-based exposure therapy] enhance treatment efficacy, while using anxiolytics such as benzodiazepines as adjuncts can undermine long-term treatment success. The purpose of this review is to outline the literature showing how pharmacological interventions targeting neurotransmitter systems including serotonin, dopamine, noradrenaline, histamine, glutamate, GABA, cannabinoids, neuropeptides (oxytocin, neuropeptides Y and S, opioids) and other targets (neurotrophins BDNF and FGF2, glucocorticoids, L-type-calcium channels, epigenetic modifications) as well as their downstream signaling pathways, can augment fear extinction and strengthen extinction memory persistently in preclinical models. Particularly promising approaches are discussed in regard to their effects on specific aspects of fear extinction namely, acquisition, consolidation and retrieval, including long-term protection from return of fear (relapse) phenomena like spontaneous recovery, reinstatement and renewal of fear. We also highlight the promising translational value of the preclinial research and the clinical potential of targeting certain neurochemical systems with, for example d-cycloserine, yohimbine, cortisol, and L-DOPA. The current body of research reveals important new insights into the neurobiology and neurochemistry of fear extinction and holds significant promise for pharmacologically-augmented psychotherapy as an improved approach to treat trauma and anxiety-related disorders in a more efficient and persistent way promoting enhanced symptom remission and recovery.
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Affiliation(s)
- N Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria.
| | - C Schmuckermair
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - N Whittle
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - A Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
| | - K J Ressler
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
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29
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Markota M, Sin J, Pantazopoulos H, Jonilionis R, Berretta S. Reduced dopamine transporter expression in the amygdala of subjects diagnosed with schizophrenia. Schizophr Bull 2014; 40:984-91. [PMID: 24936023 PMCID: PMC4133683 DOI: 10.1093/schbul/sbu084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A disruption of dopaminergic transmission in the amygdala of subjects with schizophrenia was proposed as a main contributor to pathophysiological and clinical manifestations of this disorder. We tested the hypothesis that the expression of the dopamine transporter (DAT) is decreased in the amygdala of subjects with schizophrenia. In normal control, schizophrenic subjects and bipolar disorder subjects, we measured numerical density of axon varicosities immunoreactive (IR) for DAT in the lateral (LN), basal, accessory basal (ABN), and cortical (CO) nuclei and intercalated cell masses (ITCM) of the amygdala. Tyrosine hydroxylase (TH)-IR and dopamine beta-hydroxylase (DBH)-IR varicosities were measured to test for potential loss of varicosities and serotonin transporter (5HTT)-IR for involvement of the serotoninergic system. Among several potential confounding variables tested, particular emphasis was placed on exposure to therapeutic drugs. In schizophrenic subjects, DAT-IR varicosities were decreased in LN (P = .0002), ABN (P = .013), and CO (P = .0001) in comparison with controls, and in comparison with bipolar disorder subjects in LN (P = .004) and CO (P = .002). DBH-IR varicosities were decreased in ABN (P = .008) and ITCM (P = .017), compared with controls. TH- and 5HTT-IR varicosities were not altered. No changes were detected in bipolar disorder. Taken together with TH and DBH findings, reductions of DAT-IR varicosities point to decreased DAT expression in dopaminergic terminals in the amygdala of subjects with schizophrenia. This DAT decrease may disrupt dopamine uptake, leading to increased dopaminergic synaptic transmission and spillage into the extracellular space with activation of extrasynaptic dopamine receptors. Concurrent decrease of noradrenaline in the ABN may disrupt memory consolidation.
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Affiliation(s)
- Matej Markota
- Department of Psychiatry, Harvard Medical School, Boston, MA;,Translational Neuroscience Laboratory, Mclean Hospital, Belmont, MA
| | - Jessica Sin
- Department of Psychiatry, Harvard Medical School, Boston, MA
| | - Harry Pantazopoulos
- Department of Psychiatry, Harvard Medical School, Boston, MA;,Translational Neuroscience Laboratory, Mclean Hospital, Belmont, MA
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30
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Bukalo O, Pinard CR, Holmes A. Mechanisms to medicines: elucidating neural and molecular substrates of fear extinction to identify novel treatments for anxiety disorders. Br J Pharmacol 2014; 171:4690-718. [PMID: 24835117 DOI: 10.1111/bph.12779] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/28/2014] [Accepted: 05/04/2014] [Indexed: 12/11/2022] Open
Abstract
The burden of anxiety disorders is growing, but the efficacy of available anxiolytic treatments remains inadequate. Cognitive behavioural therapy for anxiety disorders focuses on identifying and modifying maladaptive patterns of thinking and behaving, and has a testable analogue in rodents in the form of fear extinction. A large preclinical literature has amassed in recent years describing the neural and molecular basis of fear extinction in rodents. In this review, we discuss how this work is being harnessed to foster translational research on anxiety disorders and facilitate the search for new anxiolytic treatments. We begin by summarizing the anatomical and functional connectivity of a medial prefrontal cortex (mPFC)-amygdala circuit that subserves fear extinction, including new insights from optogenetics. We then cover some of the approaches that have been taken to model impaired fear extinction and associated impairments with mPFC-amygdala dysfunction. The principal goal of the review is to evaluate evidence that various neurotransmitter and neuromodulator systems mediate fear extinction by modulating the mPFC-amygdala circuitry. To that end, we describe studies that have tested how fear extinction is impaired or facilitated by pharmacological manipulations of dopamine, noradrenaline, 5-HT, GABA, glutamate, neuropeptides, endocannabinoids and various other systems, which either directly target the mPFC-amygdala circuit, or produce behavioural effects that are coincident with functional changes in the circuit. We conclude that there are good grounds to be optimistic that the progress in defining the molecular substrates of mPFC-amygdala circuit function can be effectively leveraged to identify plausible candidates for extinction-promoting therapies for anxiety disorders.
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Affiliation(s)
- Olena Bukalo
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
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Hübner C, Bosch D, Gall A, Lüthi A, Ehrlich I. Ex vivo dissection of optogenetically activated mPFC and hippocampal inputs to neurons in the basolateral amygdala: implications for fear and emotional memory. Front Behav Neurosci 2014; 8:64. [PMID: 24634648 PMCID: PMC3943336 DOI: 10.3389/fnbeh.2014.00064] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/13/2014] [Indexed: 12/03/2022] Open
Abstract
Many lines of evidence suggest that a reciprocally interconnected network comprising the amygdala, ventral hippocampus (vHC), and medial prefrontal cortex (mPFC) participates in different aspects of the acquisition and extinction of conditioned fear responses and fear behavior. This could at least in part be mediated by direct connections from mPFC or vHC to amygdala to control amygdala activity and output. However, currently the interactions between mPFC and vHC afferents and their specific targets in the amygdala are still poorly understood. Here, we use an ex-vivo optogenetic approach to dissect synaptic properties of inputs from mPFC and vHC to defined neuronal populations in the basal amygdala (BA), the area that we identify as a major target of these projections. We find that BA principal neurons (PNs) and local BA interneurons (INs) receive monosynaptic excitatory inputs from mPFC and vHC. In addition, both these inputs also recruit GABAergic feedforward inhibition in a substantial fraction of PNs, in some neurons this also comprises a slow GABAB-component. Amongst the innervated PNs we identify neurons that project back to subregions of the mPFC, indicating a loop between neurons in mPFC and BA, and a pathway from vHC to mPFC via BA. Interestingly, mPFC inputs also recruit feedforward inhibition in a fraction of INs, suggesting that these inputs can activate dis-inhibitory circuits in the BA. A general feature of both mPFC and vHC inputs to local INs is that excitatory inputs display faster rise and decay kinetics than in PNs, which would enable temporally precise signaling. However, mPFC and vHC inputs to both PNs and INs differ in their presynaptic release properties, in that vHC inputs are more depressing. In summary, our data describe novel wiring, and features of synaptic connections from mPFC and vHC to amygdala that could help to interpret functions of these interconnected brain areas at the network level.
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Affiliation(s)
- Cora Hübner
- Hertie Institute for Clinical Brain Research and Centre for Integrative Neuroscience, University of Tuebingen Tuebingen, Germany ; Graduate School of Neural and Behavioral Sciences, IMPRS Tuebingen, Germany
| | - Daniel Bosch
- Hertie Institute for Clinical Brain Research and Centre for Integrative Neuroscience, University of Tuebingen Tuebingen, Germany
| | - Andrea Gall
- Hertie Institute for Clinical Brain Research and Centre for Integrative Neuroscience, University of Tuebingen Tuebingen, Germany
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research Basel, Switzerland
| | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain Research and Centre for Integrative Neuroscience, University of Tuebingen Tuebingen, Germany
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32
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Zhang X, Jiang X. Effects of Enteral Nutrition on the Barrier Function of the Intestinal Mucosa and Dopamine Receptor Expression in Rats With Traumatic Brain Injury. JPEN J Parenter Enteral Nutr 2013; 39:114-23. [DOI: 10.1177/0148607113501881] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Xuan Zhang
- School of Nursing, Fujian Medical University, Fuzhou, China
| | - Xiaoying Jiang
- School of Nursing, Fujian Medical University, Fuzhou, China
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33
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Synaptic connectivity between rat striatal spiny projection neurons in vivo: Unexpected multiple somatic innervation in the context of overall sparse proximal connectivity. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.baga.2013.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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34
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Hill JE, Gasser PJ. Organic cation transporter 3 is densely expressed in the intercalated cell groups of the amygdala: anatomical evidence for a stress hormone-sensitive dopamine clearance system. J Chem Neuroanat 2013; 52:36-43. [PMID: 23694905 DOI: 10.1016/j.jchemneu.2013.04.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 11/16/2022]
Abstract
The intercalated cell groups of the amygdala (ITCs) are clusters of GABAergic neurons which exert powerful modulatory control of amygdala output, and are thought to play key roles in the extinction of conditioned fear responses. Dopamine, acting through D1 receptors, inhibits ITC neuronal activity, an action that has the potential to disinhibit amygdala activity, leading to changes in behavioral responses. Dopaminergic neurotransmission in the ITC occurs through a combination of synaptic and volume transmission. Thus, mechanisms, including transport mechanisms, that regulate extracellular dopamine concentrations in the ITC, are likely to be important determinants of amygdala function. We have recently demonstrated the expression of organic cation transporter 3 (OCT3), a high-capacity transporter for dopamine and other monoamines, throughout the rat brain. In this study, we used immunohistochemical and immunofluorescence techniques to examine the distribution of OCT3 in the ITC, to identify the phenotype of OCT3-expressing cells, and to describe the spatial relationships of OCT3 to dopaminergic terminals and dopamine D1 receptors in these areas. We observed high densities of OCT3-immunoreactive perikarya and punctae throughout the D1 receptor-rich main, anterior and paracapsular ITCs, in contrast with the basolateral amygdala, where OCT3 immunoreactive perikarya and puncta were observed at much lower density. OCT3-immunoreactive perikarya in the ITC were identified as neurons. Tyrosine hydroxylase-immunoreactive fibers in the ITC were immunonegative for OCT3, though OCT3-immunoreactive punctae were observed in close proximity to TH+ terminals. Punctate OCT3-immunoreactivity in the ITCs was observed in very close proximity (<1 μm) to D1 receptor immunoreactivity. These anatomical data are consistent with the hypothesis that OCT3 plays a central role in regulating dopaminergic neurotransmission in the ITC, and that it represents a post- or peri-synaptic dopamine clearance mechanism. Inhibition of OCT3-mediated transport by corticosterone may represent a mechanism by which acute stress alters dopaminergic neurotransmission in the amygdala, leading to alterations in fear and anxiety-like behavior.
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Affiliation(s)
- Jonathan E Hill
- Department of Biomedical Sciences, Marquette University, 516 N 15th Street, Milwaukee, WI 53233, USA.
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35
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Active avoidance learning requires prefrontal suppression of amygdala-mediated defensive reactions. J Neurosci 2013; 33:3815-23. [PMID: 23447593 DOI: 10.1523/jneurosci.2596-12.2013] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Signaled active avoidance (AA) paradigms train subjects to prevent an aversive outcome by performing a learned behavior during the presentation of a conditioned cue. This complex form of conditioning involves pavlovian and instrumental components, which produce competing behavioral responses that must be reconciled for the subject to successfully avoid an aversive stimulus. In signaled AA paradigm for rat, we tested the hypothesis that the instrumental component of AA training recruits infralimbic prefrontal cortex (ilPFC) to inhibit central amygdala (CeA)-mediated Pavlovian reactions. Pretraining lesions of ilPFC increased conditioned freezing while causing a corresponding decrease in avoidance; lesions of CeA produced opposite effects, reducing freezing and facilitating avoidance behavior. Pharmacological inactivation experiments demonstrated that ilPFC is relevant to both acquisition and expression phases of AA learning. Inactivation experiments also revealed that AA produces an ilPFC-mediated diminution of pavlovian reactions that extends beyond the training context, even when the conditioned stimulus is presented in an environment that does not allow the avoidance response. Finally, injection of a protein synthesis inhibitor into either ilPFC or CeA impaired or facilitated AA, respectively, showing that avoidance training produces two opposing memory traces in these regions. These data support a model in which AA learning recruits ilPFC to inhibit CeA-mediated defense behaviors, leading to a robust suppression of freezing that generalizes across environments. Thus, ilPFC functions as an inhibitory interface, allowing instrumental control over an aversive outcome to attenuate the expression of freezing and other reactions to conditioned threat.
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36
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John YJ, Bullock D, Zikopoulos B, Barbas H. Anatomy and computational modeling of networks underlying cognitive-emotional interaction. Front Hum Neurosci 2013; 7:101. [PMID: 23565082 PMCID: PMC3613599 DOI: 10.3389/fnhum.2013.00101] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 03/11/2013] [Indexed: 11/13/2022] Open
Abstract
The classical dichotomy between cognition and emotion equated the first with rationality or logic and the second with irrational behaviors. The idea that cognition and emotion are separable, antagonistic forces competing for dominance of mind has been hard to displace despite abundant evidence to the contrary. For instance, it is now known that a pathological absence of emotion leads to profound impairment of decision making. Behavioral observations of this kind are corroborated at the mechanistic level: neuroanatomical studies reveal that brain areas typically described as underlying either cognitive or emotional processes are linked in ways that imply complex interactions that do not resemble a simple mutual antagonism. Instead, physiological studies and network simulations suggest that top-down signals from prefrontal cortex realize "cognitive control" in part by either suppressing or promoting emotional responses controlled by the amygdala, in a way that facilitates adaptation to changing task demands. Behavioral, anatomical, and physiological data suggest that emotion and cognition are equal partners in enabling a continuum or matrix of flexible behaviors that are subserved by multiple brain regions acting in concert. Here we focus on neuroanatomical data that highlight circuitry that structures cognitive-emotional interactions by directly or indirectly linking prefrontal areas with the amygdala. We also present an initial computational circuit model, based on anatomical, physiological, and behavioral data to explicitly frame the learning and performance mechanisms by which cognition and emotion interact to achieve flexible behavior.
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Affiliation(s)
- Yohan J John
- Neural Systems Laboratory, Boston University Boston, MA, USA
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37
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Marek R, Strobel C, Bredy TW, Sah P. The amygdala and medial prefrontal cortex: partners in the fear circuit. J Physiol 2013; 591:2381-91. [PMID: 23420655 DOI: 10.1113/jphysiol.2012.248575] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Fear conditioning and fear extinction are Pavlovian conditioning paradigms extensively used to study the mechanisms that underlie learning and memory formation. The neural circuits that mediate this learning are evolutionarily conserved, and seen in virtually all species from flies to humans. In mammals, the amygdala and medial prefrontal cortex are two structures that play a key role in the acquisition, consolidation and retrieval of fear memory, as well extinction of fear. These two regions have extensive bidirectional connections, and in recent years, the neural circuits that mediate fear learning and fear extinction are beginning to be elucidated. In this review, we provide an overview of our current understanding of the neural architecture within the amygdala and medial prefrontal cortex. We describe how sensory information is processed in these two structures and the neural circuits between them thought to mediate different aspects of fear learning. Finally, we discuss how changes in circuits within these structures may mediate fear responses following fear conditioning and extinction.
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Affiliation(s)
- Roger Marek
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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38
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Target-specific suppression of GABA release from parvalbumin interneurons in the basolateral amygdala by dopamine. J Neurosci 2013; 32:14815-20. [PMID: 23077066 DOI: 10.1523/jneurosci.2997-12.2012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) in the basolateral amygdala (BLA) promotes fear learning by disinhibiting principal neurons (PNs) and enabling synaptic plasticity in their sensory inputs. While BLA interneurons (INs) are heterogeneous, it is unclear which interneuron subtypes decrease GABAergic input to PNs in the presence of DA. Here, using cell type-selective photostimulation by channelrhodopsin 2 in BLA slices from mouse brain, we examined the role of parvalbumin-positive INs (PV-INs), the major interneuronal subpopulation in BLA, in the disinhibitory effect of DA. We found that DA selectively suppressed GABAergic transmission from PV-INs to PNs by acting on presynaptic D(2) receptors, and this effect was mimicked by Rp-cAMP, an inhibitor of cAMP-dependent signaling. In contrast, DA did not alter GABA release from PV-INs to INs. Furthermore, neither suppressing cAMP-dependent signaling by Rp-cAMP nor enhancing it by forskolin altered GABA release from PV-INs to BLA INs. Overall, DA disinhibits BLA, at least in part, by suppressing GABA release from PV-INs in the target cell-specific manner that results from differential control of this release by cAMP-dependent signaling.
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39
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Palomares-Castillo E, Hernández-Pérez OR, Pérez-Carrera D, Crespo-Ramírez M, Fuxe K, Pérez de la Mora M. The intercalated paracapsular islands as a module for integration of signals regulating anxiety in the amygdala. Brain Res 2012; 1476:211-34. [DOI: 10.1016/j.brainres.2012.03.047] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/15/2012] [Accepted: 03/19/2012] [Indexed: 11/30/2022]
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40
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Marcellino D, Frankowska M, Agnati L, Perez de la Mora M, Vargas-Barroso V, Fuxe K, Larriva-Sahd J. Intercalated and paracapsular cell islands of the adult rat amygdala: a combined rapid-Golgi, ultrastructural, and immunohistochemical account. Neuroscience 2012; 226:324-47. [PMID: 22986165 DOI: 10.1016/j.neuroscience.2012.08.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/31/2012] [Accepted: 08/31/2012] [Indexed: 11/19/2022]
Abstract
The anterior and rostral paracapsular intercalated islands (AIC and PIC, respectively) were studied in the context of the amygdaloid modulation of fear/anxiety using horizontal sections. The structural analysis carried out using silver-impregnated specimens revealed that the AIC is composed of tightly packed, medium-sized spiny neurons with distinct dendritic and axonal patterns that send projecting axons to the central nucleus of the amygdala. The AIC occupies a strategic position between the basolateral amygdaloid complex and the caudal limb of the anterior commissure from which it receives fibers en passage and axon terminals. Electron microscopic observation of terminal (i.e., synaptic) degeneration 72 h after the surgical interruption of the anterior commissure, confirms the synaptic interaction between the latter and the AIC neurons. These observations suggest that these islands may gate the activity of neurons from the contralateral basal forebrain and synchronize the anxiogenic output of both amygdalae. Immunohistochemical analysis indicated that, within the AIC and rostral PIC, the distance between tyrosine hydroxylase-immunoreactive terminals and the punctate dopamine D(1) receptor immunoreactivity, was in the micrometer range. These results indicate a short distance and a rapid extrasynaptic form of dopamine volume transmission mediated via D(1) receptors in the AIC and PIC which may enhance fear and anxiety by suppressing feed-forward inhibition in the basolateral and central amygdaloid nuclei. The strong suggestion for a commissural axon projection to the AIC documented here, coupled with the previous evidences indicting an isocortical and amygdalar contributions to the anterior commissure, opens the possibility that the AIC may be involved in decoding nerve impulses arising from both the ipsi- and contra-lateral forebrain to, in turn, modulate the homolateral amygdala.
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Affiliation(s)
- D Marcellino
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
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41
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Fisher PM, Hariri AR. Linking variability in brain chemistry and circuit function through multimodal human neuroimaging. GENES BRAIN AND BEHAVIOR 2012; 11:633-42. [PMID: 22443230 DOI: 10.1111/j.1601-183x.2012.00786.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Identifying neurobiological mechanisms mediating the emergence of individual differences in behavior is critical for advancing our understanding of relative risk for psychopathology. Neuroreceptor positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) can be used to assay in vivo regional brain chemistry and function, respectively. Typically, these neuroimaging modalities are implemented independently despite the capacity for integrated data sets to offer unique insight into molecular mechanisms associated with brain function. Through examples from the serotonin and dopamine system and its effects on threat- and reward-related brain function, we review evidence for how such a multimodal neuroimaging strategy can be successfully implemented. Furthermore, we discuss how multimodal PET-fMRI can be integrated with techniques such as imaging genetics, pharmacological challenge paradigms and gene-environment interaction models to more completely map biological pathways mediating individual differences in behavior and related risk for psychopathology and inform the development of novel therapeutic targets.
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Affiliation(s)
- P M Fisher
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
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42
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Chronic morphine treatment switches the effect of dopamine on excitatory synaptic transmission from inhibition to excitation in pyramidal cells of the basolateral amygdala. J Neurosci 2012; 31:17527-36. [PMID: 22131414 DOI: 10.1523/jneurosci.3806-11.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dopaminergic signaling in the basolateral amygdala (BLA) is important for drug-stimulus learning that triggers relapse to drug-seeking behavior. However, little is known about adaptive changes in this signaling pathway upon chronic morphine treatment. In this paper, we observed the influence of chronic morphine treatment on the effect of dopamine (DA) on the excitatory transmission in the pyramidal cells of BLA in slices with the whole-cell patch-clamp method. We also studied its mechanism and significance with pharmacological approaches combined with biochemical and behavioral techniques. The results showed that chronic morphine exposure switched the effect of DA on the excitatory synaptic transmission from inhibition to excitation; the chronic morphine-induced switching action on the effect of DA was due to its influence on D1 receptors; the site of the effect of chronic morphine treatment on D1 receptors was at presynaptic locus; chronic morphine treatment induced a significant increase in the amount of D1 receptor expression in the synaptosomes and synaptosomal membrane fraction from BLA; the enhancement of presynaptic glutamate release by D1 receptor agonist upon chronic morphine treatment was dependent on the activation of cAMP-dependent protein kinase; and the intra-BLA injection of D1 receptor antagonist canceled the conditioned place aversion (CPA) in morphine-dependent rats. In conclusion, chronic morphine treatment switches the effect of DA on the excitatory synaptic transmission from inhibition to excitation by the presynaptic D1 receptor amount increase-mediated glutamate release in the pyramidal cells of BLA and the blockade of D1 receptors in BLA cancels CPA in morphine-dependent rats.
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43
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Medial prefrontal cortical innervation of the intercalated nuclear region of the amygdala. Neuroscience 2012; 205:112-24. [PMID: 22249157 DOI: 10.1016/j.neuroscience.2011.12.036] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 11/21/2022]
Abstract
The projections of the infralimbic area (IL) of the medial prefrontal cortex to the intercalated nuclei (ICNs) of the amygdala are thought to form a critical component of the forebrain circuitry for fear extinction. Despite the importance of these projections, there have been no focussed anatomical studies that have investigated the extent of IL inputs to different portions of the ICN complex. The present investigation used anterograde tract tracing in the rat to study the projections of the ventromedial PFC, including the IL, to the ICNs and surrounding amygdalar regions. Immunohistochemistry for the μ-opioid receptor (MOR) was used to identify the ICNs. At rostral levels of the amygdala there was a very dense projection to a far lateral portion of the capsular subdivision of the central nucleus (CLC) located between the main and medial ICNs, but only very light projections to these ICNs and the lateral ICNs. This distinct portion of the CLC receiving strong IL inputs was termed the capsular infralimbic target zone (CITZ), and was MOR-negative. Likewise, at more caudal levels of the amygdala, IL projections to the medial, lateral, and dorsal ICNs were light to moderate compared with projections to adjacent portions of the basolateral amygdala and amygdalostriatal transitional area. These findings suggest that the putative role of the IL-to-ICN connection in fear inhibition may be mediated by light to moderate projections from the IL to the medial ICN, and that the CITZ may be an equally important amygdalar target for this function.
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44
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Mora F, Segovia G, Del Arco A, de Blas M, Garrido P. Stress, neurotransmitters, corticosterone and body-brain integration. Brain Res 2012; 1476:71-85. [PMID: 22285436 DOI: 10.1016/j.brainres.2011.12.049] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 12/26/2022]
Abstract
Stress can be defined as a brain-body reaction towards stimuli arising from the environment or from internal cues that are interpreted as a disruption of homeostasis. The organization of the response to a stressful situation involves not only the activity of different types of neurotransmitter systems in several areas of the limbic system, but also the response of neurons in these areas to several other chemicals and hormones, chiefly glucocorticoids, released from peripheral organs and glands. Thus, stress is probably the process through which body-brain integration plays a major role. Here we review first the responses to an acute stress in terms of neurotransmitters such as dopamine, acetylcholine, glutamate and GABA in areas of the brain involved in the regulation of stress responses. These areas include the prefrontal cortex, amygdala, hippocampus and nucleus accumbens and the interaction among those areas. Then, we consider the role of glucocorticoids and review some recent data about the interaction of these steroids with several neurotransmitters in those same areas of the brain. Also the actions of other substances (neuromodulators) released from peripheral organs such as the pancreas, liver or gonads (insulin, IGF-1, estrogens) are reviewed. The role of an environmental enrichment on these same responses is also discussed. Finally a section is devoted to put into perspective all these environmental-brain-body-brain interactions during stress and their consequences on aging. It is concluded that the integrative perspective framed in this review is relevant for better understanding of how the organism responds to stressful challenges and how this can be modified through different environmental conditions during the process of aging. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Francisco Mora
- Department of Physiology, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
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45
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Duffy AM, Fitzgerald ML, Chan J, Robinson DC, Milner TA, Mackie K, Pickel VM. Acetylcholine α7 nicotinic and dopamine D2 receptors are targeted to many of the same postsynaptic dendrites and astrocytes in the rodent prefrontal cortex. Synapse 2011; 65:1350-67. [PMID: 21858872 PMCID: PMC3356922 DOI: 10.1002/syn.20977] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The alpha-7 nicotinic acetylcholine receptor (α7nAChR) and the dopamine D(2) receptor (D(2) R) are both implicated in attentional processes and cognition, mediated in part through the prefrontal cortex (PFC). We examined the dual electron microscopic immunolabeling of α7nAChR and either D(2) R or the vesicular acetylcholine transporter (VAChT) in rodent PFC to assess convergent functional activation sites. Immunoreactivity (ir) for α7nAChR and/or D(2) R was seen in the same as well as separate neuronal and glial profiles. At least half of the dually labeled profiles were somata and dendrites, while most labeled axon terminals expressed only D(2) R-ir. The D(2) R-labeled terminals were without synaptic specializations or formed inhibitory or excitatory-type synapses with somatodendritic profiles, some of which expressed the α7nAChR and/or D(2) R. Astrocytic glial processes comprised the majority of nonsomatodendritic α7nAChR or α7nAChR and D(2) R-labeled profiles. Glial processes containing α7nAChR-ir were frequently located near VAChT-labeled terminals and also showed perisynaptic and perivascular associations. We conclude that in rodent PFC α7nACh and D(2) R activation can dually modulate (1) postsynaptic dendritic responses within the same or separate but synaptically linked neurons in which the D(2) R has the predominately presynaptic distribution, and (2) astrocytic signaling that may be crucial for synaptic transmission and functional hyperemia.
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Affiliation(s)
- Aine M. Duffy
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
| | - Megan L. Fitzgerald
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
| | - June Chan
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
| | - Danielle C. Robinson
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
| | - Teresa A. Milner
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York 10065
| | - Kenneth Mackie
- Department of Psychological and Brain Sciences and the Gill Center, Indiana University, Bloomington, Indiana 47405
| | - Virginia M. Pickel
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065
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46
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Hoover WB, Vertes RP. Projections of the medial orbital and ventral orbital cortex in the rat. J Comp Neurol 2011; 519:3766-801. [DOI: 10.1002/cne.22733] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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47
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Identification of a dopamine receptor-mediated opiate reward memory switch in the basolateral amygdala-nucleus accumbens circuit. J Neurosci 2011; 31:11172-83. [PMID: 21813678 DOI: 10.1523/jneurosci.1781-11.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The basolateral amygdala (BLA), ventral tegmental area (VTA), and nucleus accumbens (NAc) play central roles in the processing of opiate-related associative reward learning and memory. The BLA receives innervation from dopaminergic fibers originating in the VTA, and both dopamine (DA) D1 and D2 receptors are expressed in this region. Using a combination of in vivo single-unit extracellular recording in the NAc combined with behavioral pharmacology studies, we have identified a double dissociation in the functional roles of DA D1 versus D2 receptor transmission in the BLA, which depends on opiate exposure state; thus, in previously opiate-naive rats, blockade of intra-BLA D1, but not D2, receptor transmission blocked the acquisition of associative opiate reward memory, measured in an unbiased conditioned place preference procedure. In direct contrast, in rats made opiate dependent and conditioned in a state of withdrawal, intra-BLA D2, but not D1, receptor blockade blocked opiate reward encoding. This functional switch was dependent on cAMP signaling as comodulation of intra-BLA cAMP levels reversed or replicated the functional effects of intra-BLA D1 or D2 transmission during opiate reward processing. Single-unit in vivo extracellular recordings performed in neurons of the NAc confirmed an opiate-state-dependent role for BLA D1/D2 transmission in NAc neuronal response patterns to morphine. Our results characterize and identify a novel opiate addiction switching mechanism directly in the BLA that can control the processing of opiate reward information as a direct function of opiate exposure state via D1 or D2 receptor signaling substrates.
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48
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Ohshiro H, Kubota S, Murakoshi T. Dopaminergic modulation of oscillatory network inhibition in the rat basolateral amygdala depends on initial activity state. Neuropharmacology 2011; 61:857-66. [PMID: 21683087 DOI: 10.1016/j.neuropharm.2011.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 05/02/2011] [Accepted: 06/01/2011] [Indexed: 11/30/2022]
Abstract
The amygdala receives dopaminergic innervation, and dopamine (DA) enhances various activities in cognitive and emotional behaviors. Periodic bursts of spontaneous inhibitory postsynaptic currents (IPSCs) with a low (<1 Hz) inter-event frequency have been observed in projection neurons of the basolateral nucleus of the amygdala (BL). Blockade of ionotropic glutamate receptors or GABA(A) receptors abolishes these oscillatory IPSC bursts in the BL, suggesting that the activity has a network origin. Here, we investigated dopaminergic modulation of the oscillatory network inhibition in rat brain slices. We evaluated the effects of DA receptor agonists and antagonists on the network inhibition; the resultant changes were quantified by integrated power spectral density (0.1-3.0 Hz). DA enhanced the power when its initial activity was low, but reduced it when the activity was initially robust. These changes in the power were accompanied by changes in burst IPSC amplitude. D1-like receptor agonist SKF 38393, or DA together with the D2-like receptor antagonist sulpiride, reproduced DA's facilitatory actions. D2-like receptor agonist quinpirole did not change the periodic IPSC burst activity of the high baseline power, though D(4) receptor agonist PD 168077, or DA together with the D1-like receptor antagonist SCH 23390, reduced its activity. These results suggest that: 1) dopaminergic modulation of the oscillatory network inhibition depends on its initial activity; and 2) facilitatory and suppressing effects of DA in the BL are mediated by D1-like receptors and D(4) receptors, respectively.
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Affiliation(s)
- Hironori Ohshiro
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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Different fear states engage distinct networks within the intercalated cell clusters of the amygdala. J Neurosci 2011; 31:5131-44. [PMID: 21451049 DOI: 10.1523/jneurosci.6100-10.2011] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although extinction-based therapies are among the most effective treatments for anxiety disorders, the neural bases of fear extinction remain still essentially unclear. Recent evidence suggests that the intercalated cell masses of the amygdala (ITCs) are critical structures for fear extinction. However, the neuronal organization of ITCs and how distinct clusters contribute to different fear states are still entirely unknown. Here, by combining whole-cell patch-clamp recordings and biocytin labeling with full anatomical reconstruction of the filled neurons and ultrastructural analysis of their synaptic contacts, we have elucidated the cellular organization and efferent connections of one of the main ITC clusters in mice. Our data showed an unexpected heterogeneity in the axonal pattern of medial paracapsular ITC (Imp) neurons and the presence of three distinct neuronal subtypes. Functionally, we observed that the Imp was preferentially activated during fear expression, whereas extinction training and extinction retrieval activated the main ITC nucleus (IN), as measured by quantifying Zif268 expression. This can be explained by the IPSPs evoked in the IN after Imp stimulation, most likely through the GABAergic monosynaptic innervation of IN neurons by one subtype of Imp cells, namely the medial capsular-projecting (MCp)-Imp neurons. MCp-Imp neurons also target large ITC cells that surround ITC clusters and express the metabotropic glutamate receptor 1α. These findings reveal a distinctive participation of ITC clusters to different fear states and the underlying anatomical circuitries, hence shedding new light on ITC networks and providing a novel framework to elucidate their role in fear expression and extinction.
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Kim YB, Matthews M, Moghaddam B. Putative γ-aminobutyric acid neurons in the ventral tegmental area have a similar pattern of plasticity as dopamine neurons during appetitive and aversive learning. Eur J Neurosci 2011; 32:1564-72. [PMID: 21040517 DOI: 10.1111/j.1460-9568.2010.07371.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dopamine influences affective, motor and cognitive processing, and multiple forms of learning and memory. This multifaceted functionality, which operates across long temporal windows, is broader than the narrow and temporally constrained role often ascribed to dopamine neurons as reward prediction error detectors. Given the modulatory nature of dopamine neurotransmission, that dopamine release is activated by both aversive and appetitive stimuli, and that dopamine receptors are often localized extrasynaptically, a role for dopamine in transmitting precise error signals has been questioned. Here we recorded from ventral tegmental area (VTA) neurons, while exposing rats to novel stimuli that were predictive of an appetitive or aversive outcome in the same behavioral session. The VTA contains dopamine and -aminobutyric acid (GABA) neurons that project to striatal and cortical regions and are strongly implicated in learning and affective processing. The response of VTA neurons, regardless of whether they had putative dopamine or GABA waveforms, transformed flexibly as animals learned to associate novel stimuli from different sensory modalities to appetitive or aversive outcomes. Learning the appetitive association led to larger excitatory VTA responses, whereas acquiring the aversive association led to a biphasic response of brief excitation followed by sustained inhibition. These responses shifted rapidly as outcome contingencies changed. These data suggest that VTA neurons interface sensory information with representational memory of aversive and appetitive events. This pattern of plasticity was not selective for putative dopamine neurons and generalized to other cells, suggesting that the temporally precise information transfer from the VTA may be mediated by faster acting GABA neurons.
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Affiliation(s)
- Yun-Bok Kim
- Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, Pittsburgh, PA 15260, USA
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