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Cattani A, Arnold DB, McCarthy M, Kopell N. Basolateral amygdala oscillations enable fear learning in a biophysical model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.28.538604. [PMID: 37163011 PMCID: PMC10168360 DOI: 10.1101/2023.04.28.538604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The basolateral amygdala (BLA) is a key site where fear learning takes place through synaptic plasticity. Rodent research shows prominent low theta (~3-6 Hz), high theta (~6-12 Hz), and gamma (>30 Hz) rhythms in the BLA local field potential recordings. However, it is not understood what role these rhythms play in supporting the plasticity. Here, we create a biophysically detailed model of the BLA circuit to show that several classes of interneurons (PV, SOM, and VIP) in the BLA can be critically involved in producing the rhythms; these rhythms promote the formation of a dedicated fear circuit shaped through rhythmic gating of spike-timing-dependent plasticity. Each class of interneurons is necessary for the plasticity. We find that the low theta rhythm is a biomarker of successful fear conditioning. Finally, we discuss how the peptide released by the VIP cell may alter the dynamics of plasticity to support the necessary fine timing.
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Affiliation(s)
- Anna Cattani
- Department of Mathematics & Statistics, Boston University, Boston, Massachusetts, United States
| | - Don B Arnold
- Department of Biology, University of Southern California, Los Angeles, California, United States
| | - Michelle McCarthy
- Department of Mathematics & Statistics, Boston University, Boston, Massachusetts, United States
| | - Nancy Kopell
- Department of Mathematics & Statistics, Boston University, Boston, Massachusetts, United States
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2
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Li Y, Zhi W, Qi B, Wang L, Hu X. Update on neurobiological mechanisms of fear: illuminating the direction of mechanism exploration and treatment development of trauma and fear-related disorders. Front Behav Neurosci 2023; 17:1216524. [PMID: 37600761 PMCID: PMC10433239 DOI: 10.3389/fnbeh.2023.1216524] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023] Open
Abstract
Fear refers to an adaptive response in the face of danger, and the formed fear memory acts as a warning when the individual faces a dangerous situation again, which is of great significance to the survival of humans and animals. Excessive fear response caused by abnormal fear memory can lead to neuropsychiatric disorders. Fear memory has been studied for a long time, which is of a certain guiding effect on the treatment of fear-related disorders. With continuous technological innovations, the study of fear has gradually shifted from the level of brain regions to deeper neural (micro) circuits between brain regions and even within single brain regions, as well as molecular mechanisms. This article briefly outlines the basic knowledge of fear memory and reviews the neurobiological mechanisms of fear extinction and relapse, which aims to provide new insights for future basic research on fear emotions and new ideas for treating trauma and fear-related disorders.
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Affiliation(s)
- Ying Li
- College of Education, Hebei University, Baoding, China
- Laboratory of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Weijia Zhi
- Laboratory of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Bing Qi
- College of Education, Hebei University, Baoding, China
| | - Lifeng Wang
- Laboratory of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Xiangjun Hu
- College of Education, Hebei University, Baoding, China
- Laboratory of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China
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3
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Singh S, Topolnik L. Inhibitory circuits in fear memory and fear-related disorders. Front Neural Circuits 2023; 17:1122314. [PMID: 37035504 PMCID: PMC10076544 DOI: 10.3389/fncir.2023.1122314] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/17/2023] [Indexed: 04/11/2023] Open
Abstract
Fear learning and memory rely on dynamic interactions between the excitatory and inhibitory neuronal populations that make up the prefrontal cortical, amygdala, and hippocampal circuits. Whereas inhibition of excitatory principal cells (PCs) by GABAergic neurons restrains their excitation, inhibition of GABAergic neurons promotes the excitation of PCs through a process called disinhibition. Specifically, GABAergic interneurons that express parvalbumin (PV+) and somatostatin (SOM+) provide inhibition to different subcellular domains of PCs, whereas those that express the vasoactive intestinal polypeptide (VIP+) facilitate disinhibition of PCs by inhibiting PV+ and SOM+ interneurons. Importantly, although the main connectivity motifs and the underlying network functions of PV+, SOM+, and VIP+ interneurons are replicated across cortical and limbic areas, these inhibitory populations play region-specific roles in fear learning and memory. Here, we provide an overview of the fear processing in the amygdala, hippocampus, and prefrontal cortex based on the evidence obtained in human and animal studies. Moreover, focusing on recent findings obtained using genetically defined imaging and intervention strategies, we discuss the population-specific functions of PV+, SOM+, and VIP+ interneurons in fear circuits. Last, we review current insights that integrate the region-specific inhibitory and disinhibitory network patterns into fear memory acquisition and fear-related disorders.
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Affiliation(s)
- Sanjay Singh
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Quebec City, QC, Canada
- Neuroscience Axis, CRCHUQ, Laval University, Quebec City, QC, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Quebec City, QC, Canada
- Neuroscience Axis, CRCHUQ, Laval University, Quebec City, QC, Canada
- *Correspondence: Lisa Topolnik
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4
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Abstract
Fear is a response to impending threat that prepares a subject to make appropriate defensive responses, whether to freeze, fight, or flee to safety. The neural circuits that underpin how subjects learn about cues that signal threat, and make defensive responses, have been studied using Pavlovian fear conditioning in laboratory rodents as well as humans. These studies have established the amygdala as a key player in the circuits that process fear and led to a model where fear learning results from long-term potentiation of inputs that convey information about the conditioned stimulus to the amygdala. In this review, we describe the circuits in the basolateral amygdala that mediate fear learning and its expression as the conditioned response. We argue that while the evidence linking synaptic plasticity in the basolateral amygdala to fear learning is strong, there is still no mechanism that fully explains the changes that underpin fear conditioning.
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Affiliation(s)
- Yajie Sun
- Queensland Brain Institute, University of Queensland, Queensland, Australia
| | - Helen Gooch
- Queensland Brain Institute, University of Queensland, Queensland, Australia
| | - Pankaj Sah
- Queensland Brain Institute, University of Queensland, Queensland, Australia.,Brain Research Centre and Department of Biology, Southern University of Science and Technology, Shenzhen, China
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5
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Polepalli JS, Gooch H, Sah P. Diversity of interneurons in the lateral and basal amygdala. NPJ SCIENCE OF LEARNING 2020; 5:10. [PMID: 32802405 PMCID: PMC7400739 DOI: 10.1038/s41539-020-0071-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 05/29/2020] [Indexed: 05/06/2023]
Abstract
The basolateral amygdala (BLA) is a temporal lobe structure that contributes to a host of behaviors. In particular, it is a central player in learning about aversive events and thus assigning emotional valence to sensory events. It is a cortical-like structure and contains glutamatergic pyramidal neurons and GABAergic interneurons. It is divided into the lateral (LA) and basal (BA) nuclei that have distinct cell types and connections. Interneurons in the BLA are a heterogenous population, some of which have been implicated in specific functional roles. Here we use optogenetics and slice electrophysiology to investigate the innervation, postsynaptic receptor stoichiometry, and plasticity of excitatory inputs onto interneurons within the BLA. Interneurons were divided into six groups based on their discharge properties, each of which received input from the auditory thalamus (AT) and auditory cortex (AC). Auditory innervation was concentrated in the LA, and optogenetic stimulation evoked robust synaptic responses in nearly all interneurons, drove many cells to threshold, and evoked disynaptic inhibition in most interneurons. Auditory input to the BA was sparse, innervated fewer interneurons, and evoked smaller synaptic responses. Biophysically, the subunit composition and distribution of AMPAR and NMDAR also differed between the two nuclei, with fewer BA IN expressing calcium permeable AMPAR, and a higher proportion expressing GluN2B-containing NMDAR. Finally, unlike LA interneurons, LTP could not be induced in the BA. These findings show that interneurons in the LA and BA are physiologically distinct populations and suggest they may have differing roles during associative learning.
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Affiliation(s)
- Jai S. Polepalli
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072 Australia
- Department of Anatomy, Yong Yoo Lin School of Medicine, National University of Singapore, Singapore, 117594 Singapore
| | - Helen Gooch
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072 Australia
| | - Pankaj Sah
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072 Australia
- Brain Research Centre and Department of Biology, Southern University of Science and Technology, Nanshan District, Shenzhen, Guangdong Province P.R. China
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6
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Meis S, Endres T, Munsch T, Lessmann V. Impact of Chronic BDNF Depletion on GABAergic Synaptic Transmission in the Lateral Amygdala. Int J Mol Sci 2019; 20:ijms20174310. [PMID: 31484392 PMCID: PMC6747405 DOI: 10.3390/ijms20174310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 01/14/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has previously been shown to play an important role in glutamatergic synaptic plasticity in the amygdala, correlating with cued fear learning. While glutamatergic neurotransmission is facilitated by BDNF signaling in the amygdala, its mechanism of action at inhibitory synapses in this nucleus is far less understood. We therefore analyzed the impact of chronic BDNF depletion on GABAA-mediated synaptic transmission in BDNF heterozygous knockout mice (BDNF+/−). Analysis of miniature and evoked inhibitory postsynaptic currents (IPSCs) in the lateral amygdala (LA) revealed neither pre- nor postsynaptic differences in BDNF+/− mice compared to wild-type littermates. In addition, long-term potentiation (LTP) of IPSCs was similar in both genotypes. In contrast, facilitation of spontaneous IPSCs (sIPSCs) by norepinephrine (NE) was significantly reduced in BDNF+/− mice. These results argue against a generally impaired efficacy and plasticity at GABAergic synapses due to a chronic BDNF deficit. Importantly, the increase in GABAergic tone mediated by NE is reduced in BDNF+/− mice. As release of NE is elevated during aversive behavioral states in the amygdala, effects of a chronic BDNF deficit on GABAergic inhibition may become evident in response to states of high arousal, leading to amygdala hyper-excitability and impaired amygdala function.
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Affiliation(s)
- Susanne Meis
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
| | - Thomas Endres
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
| | - Thomas Munsch
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
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7
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Selleck RA, Zhang W, Mercier HD, Padival M, Rosenkranz JA. Limited prefrontal cortical regulation over the basolateral amygdala in adolescent rats. Sci Rep 2018; 8:17171. [PMID: 30464293 PMCID: PMC6249319 DOI: 10.1038/s41598-018-35649-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 11/09/2018] [Indexed: 01/17/2023] Open
Abstract
Cognitive regulation of emotion develops from childhood into adulthood. This occurs in parallel with maturation of prefrontal cortical (PFC) regulation over the amygdala. The cellular substrates for this regulation may include PFC activation of inhibitory GABAergic elements in the amygdala. The purpose of this study was to determine whether PFC regulation over basolateral amygdala area (BLA) in vivo is immature in adolescence, and if this is due to immaturity of GABAergic elements or PFC excitatory inputs. Using in vivo extracellular electrophysiological recordings from anesthetized male rats we found that in vivo summation of PFC inputs to the BLA was less regulated by GABAergic inhibition in adolescents (postnatal day 39) than adults (postnatal day 72-75). In addition, stimulation of either prelimbic or infralimbic PFC evokes weaker inhibition over basal (BA) and lateral (LAT) nuclei of the BLA in adolescents. This was dictated by both weak recruitment of inhibition in LAT and weak excitatory effects of PFC in BA. The current results may contribute to differences in adolescent cognitive regulation of emotion. These findings identify specific elements that undergo adolescent maturation and may therefore be sensitive to environmental disruptions that increase risk for psychiatric disorders.
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Affiliation(s)
- Ryan A. Selleck
- 0000 0004 0388 7807grid.262641.5Cellular and Molecular Pharmacology, Center for Neurobiology of Stress Resilience and Psychiatric Disorders, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - Wei Zhang
- 0000 0004 0388 7807grid.262641.5Cellular and Molecular Pharmacology, Center for Neurobiology of Stress Resilience and Psychiatric Disorders, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - Hannah D. Mercier
- 0000 0004 0388 7807grid.262641.5Cellular and Molecular Pharmacology, Center for Neurobiology of Stress Resilience and Psychiatric Disorders, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - Mallika Padival
- 0000 0004 0388 7807grid.262641.5Cellular and Molecular Pharmacology, Center for Neurobiology of Stress Resilience and Psychiatric Disorders, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - J. Amiel Rosenkranz
- 0000 0004 0388 7807grid.262641.5Cellular and Molecular Pharmacology, Center for Neurobiology of Stress Resilience and Psychiatric Disorders, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
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8
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Lucas EK, Clem RL. GABAergic interneurons: The orchestra or the conductor in fear learning and memory? Brain Res Bull 2018; 141:13-19. [PMID: 29197563 PMCID: PMC6178932 DOI: 10.1016/j.brainresbull.2017.11.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/15/2017] [Accepted: 11/28/2017] [Indexed: 10/18/2022]
Abstract
Fear conditioning is a form of associative learning that is fundamental to survival and involves potentiation of activity in excitatory projection neurons (PNs). Current models stipulate that the mechanisms underlying this process involve plasticity of PN synapses, which exhibit strengthening in response to fear conditioning. However, excitatory PNs are extensively modulated by a diverse array of GABAergic interneurons whose contributions to acquisition, storage, and expression of fear memory remain poorly understood. Here we review emerging evidence that genetically-defined interneurons play important subtype-specific roles in processing of fear-related stimuli and that these dynamics shape PN firing through both inhibition and disinhibition. Furthermore, interneurons exhibit structural, molecular, and electrophysiological evidence of fear learning-induced synaptic plasticity. These studies warrant discarding the notion of interneurons as passive bystanders in long-term memory.
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Affiliation(s)
- Elizabeth K Lucas
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, United States
| | - Roger L Clem
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, United States; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, United States.
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9
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Krabbe S, Gründemann J, Lüthi A. Amygdala Inhibitory Circuits Regulate Associative Fear Conditioning. Biol Psychiatry 2018; 83:800-809. [PMID: 29174478 DOI: 10.1016/j.biopsych.2017.10.006] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/28/2017] [Accepted: 10/04/2017] [Indexed: 11/16/2022]
Abstract
Associative memory formation is essential for an animal's survival by ensuring adaptive behavioral responses in an ever-changing environment. This is particularly important under conditions of immediate threats such as in fear learning. One of the key brain regions involved in associative fear learning is the amygdala. The basolateral amygdala is the main entry site for sensory information to the amygdala complex, and local plasticity in excitatory basolateral amygdala principal neurons is considered to be crucial for learning of conditioned fear responses. However, activity and plasticity of excitatory circuits are tightly controlled by local inhibitory interneurons in a spatially and temporally defined manner. In this review, we provide an updated view on how distinct interneuron subtypes in the basolateral amygdala contribute to the acquisition and extinction of conditioned fear memories.
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Affiliation(s)
- Sabine Krabbe
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; University of Basel, Basel, Switzerland.
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10
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Yang Y, Wang JZ. From Structure to Behavior in Basolateral Amygdala-Hippocampus Circuits. Front Neural Circuits 2017; 11:86. [PMID: 29163066 PMCID: PMC5671506 DOI: 10.3389/fncir.2017.00086] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/17/2017] [Indexed: 01/03/2023] Open
Abstract
Emotion influences various cognitive processes, including learning and memory. The amygdala is specialized for input and processing of emotion, while the hippocampus is essential for declarative or episodic memory. During emotional reactions, these two brain regions interact to translate the emotion into particular outcomes. Here, we briefly introduce the anatomy and functions of amygdala and hippocampus, and then present behavioral, electrophysiological, optogenetic and biochemical evidence from recent studies to illustrate how amygdala and hippocampus work synergistically to form long-term memory. With recent technological advances, the causal investigations of specific neural circuit between amygdala and hippocampus will help us understand the brain mechanisms of emotion-regulated memories and improve clinical treatment of emotion-associated memory disorders in patients.
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Affiliation(s)
- Ying Yang
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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11
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Liu ZP, He QH, Pan HQ, Xu XB, Chen WB, He Y, Zhou J, Zhang WH, Zhang JY, Ying XP, Han RW, Li BM, Gao TM, Pan BX. Delta Subunit-Containing Gamma-Aminobutyric Acid A Receptor Disinhibits Lateral Amygdala and Facilitates Fear Expression in Mice. Biol Psychiatry 2017; 81:990-1002. [PMID: 27591789 DOI: 10.1016/j.biopsych.2016.06.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/07/2016] [Accepted: 06/24/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND Maintaining gamma-aminobutyric acidergic (GABAergic) inhibition in the amygdala within a physiological range is critical for the appropriate expression of emotions such as fear and anxiety. The synaptic GABA type A receptor (GABAAR) is generally known to mediate the primary component of amygdala inhibition and prevent inappropriate expression of fear. However, little is known about the contribution of the extrasynaptic GABAAR to amygdala inhibition and fear. METHODS By using mice expressing green fluorescent protein in interneurons (INs) and lacking the δ subunit-containing GABAAR (GABAA(δ)R), which is exclusively situated in the extrasynaptic membrane, we systematically investigated the role of GABAA(δ)R in regulating inhibition in the lateral amygdala (LA) and fear learning using the combined approaches of immunohistochemistry, electrophysiology, and behavior. RESULTS In sharp contrast to the established role of synaptic GABAAR in mediating LA inhibition, we found that either pharmacological or physiological recruitment of GABAA(δ)R resulted in the weakening of GABAergic transmission onto projection neurons in LA while leaving the glutamatergic transmission unaltered, suggesting disinhibition by GABAA(δ)R. The disinhibition arose from IN-specific expression of GABAA(δ)R with its activation decreasing the input resistance of local INs and suppressing their activation. Genetic deletion of GABAA(δ)R attenuated its role in suppressing LA INs and disinhibiting LA. Importantly, the GABAA(δ)R facilitated long-term potentiation in sensory afferents to LA and permitted the expression of learned fear. CONCLUSIONS Our findings suggest that GABAA(δ)R serves as a brake rather than a mediator of GABAergic inhibition in LA. The disinhibition by GABAA(δ)R may help to prevent excessive suppression of amygdala activity and thus ensure the expression of emotion.
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Affiliation(s)
- Zhi-Peng Liu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Qing-Hai He
- State Key Laboratory of Organ Failure Research, Key Laboratory of Psychiatric Disorders of Guangdong Province; Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou
| | - Han-Qing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Xiao-Bin Xu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Wen-Bing Chen
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Ye He
- Medical Experiment Center, Nanchang University, Nanchang
| | - Jin Zhou
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Wen-Hua Zhang
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Jun-Yu Zhang
- Department of Biotechnology, School of Life Sciences, Nanchang University, Nanchang
| | - Xiao-Ping Ying
- Department of Neurology, the 2nd Affiliated Hospital, , Nanchang University, Nanchang
| | - Ren-Wen Han
- Institute of Translational Medicine, Nanchang University, Nanchang
| | - Bao-Ming Li
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang
| | - Tian-Ming Gao
- State Key Laboratory of Organ Failure Research, Key Laboratory of Psychiatric Disorders of Guangdong Province; Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou
| | - Bing-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang; Department of Neurology, the 2nd Affiliated Hospital, , Nanchang University, Nanchang; Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Jiangxi, China.
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12
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Gouty-Colomer LA, Hosseini B, Marcelo IM, Schreiber J, Slump DE, Yamaguchi S, Houweling AR, Jaarsma D, Elgersma Y, Kushner SA. Arc expression identifies the lateral amygdala fear memory trace. Mol Psychiatry 2016; 21:364-75. [PMID: 25802982 PMCID: PMC4759206 DOI: 10.1038/mp.2015.18] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 11/28/2014] [Accepted: 01/08/2015] [Indexed: 12/21/2022]
Abstract
Memories are encoded within sparsely distributed neuronal ensembles. However, the defining cellular properties of neurons within a memory trace remain incompletely understood. Using a fluorescence-based Arc reporter, we were able to visually identify the distinct subset of lateral amygdala (LA) neurons activated during auditory fear conditioning. We found that Arc-expressing neurons have enhanced intrinsic excitability and are preferentially recruited into newly encoded memory traces. Furthermore, synaptic potentiation of thalamic inputs to the LA during fear conditioning is learning-specific, postsynaptically mediated and highly localized to Arc-expressing neurons. Taken together, our findings validate the immediate-early gene Arc as a molecular marker for the LA neuronal ensemble recruited during fear learning. Moreover, these results establish a model of fear memory formation in which intrinsic excitability determines neuronal selection, whereas learning-related encoding is governed by synaptic plasticity.
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Affiliation(s)
- L A Gouty-Colomer
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - B Hosseini
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - I M Marcelo
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands,Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - J Schreiber
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - D E Slump
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - S Yamaguchi
- Division of Morphological Neuroscience, Gifu University Graduate School of Medicine, Gifu, Japan,PRESTO, Japan Science and Technology Agency (JST), Saitama, Japan
| | - A R Houweling
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - D Jaarsma
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Y Elgersma
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - S A Kushner
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands,Department of Psychiatry, Erasmus University Medical Center, Dr Molewaterplein 50, Ee-1442, Rotterdam, 3015 GE, The Netherlands. E-mail:
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13
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Skelly MJ, Chappell AM, Ariwodola OJ, Weiner JL. Behavioral and neurophysiological evidence that lateral paracapsular GABAergic synapses in the basolateral amygdala contribute to the acquisition and extinction of fear learning. Neurobiol Learn Mem 2015; 127:10-6. [PMID: 26593151 DOI: 10.1016/j.nlm.2015.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 10/12/2015] [Accepted: 11/10/2015] [Indexed: 11/29/2022]
Abstract
The lateral/basolateral amygdala (BLA) is crucial to the acquisition and extinction of Pavlovian fear conditioning, and synaptic plasticity in this region is considered to be a neural correlate of learned fear. We recently reported that activation of BLA β3-adrenoreceptors (β3-ARs) selectively enhances lateral paracapsular (LPC) feed-forward GABAergic inhibition onto BLA pyramidal neurons, and that intra-BLA infusion of a β3-AR agonist reduces measures of unconditioned anxiety-like behavior. Here, we utilized a combination of behavioral and electrophysiological approaches to characterize the role of BLA LPCs in the acquisition of fear and extinction learning in adult male Long-Evans rats. We report that intra-BLA microinjection of β3-AR agonists (BRL37344 or SR58611A, 1μg/0.5μL/side) prior to training fear conditioning or extinction blocks the expression of these behaviors 24h later. Furthermore,ex vivo low-frequency stimulation of the external capsule (LFS; 1Hz, 15min), which engages LPC synapses, induces LTP of BLA fEPSPs, while application of a β3-AR agonist (SR58611A, 5μM) induces LTD of fEPSPs when combined with LFS. Interestingly, fEPSP LTP is not observed in recordings from fear conditioned animals, suggesting that fear learning may engage the same mechanisms that induce synaptic plasticity at this input. In support of this, we find that LFS produces LTD of inhibitory postsynaptic currents (iLTD) at LPC GABAergic synapses, and that this effect is also absent following fear conditioning. Taken together, these data provide preliminary evidence that modulation of LPC GABAergic synapses can influence the acquisition and extinction of fear learning and related synaptic plasticity in the BLA.
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Affiliation(s)
- M J Skelly
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - A M Chappell
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - O J Ariwodola
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - J L Weiner
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States.
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14
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Abstract
Decades of research has identified the brain areas that are involved in fear, fear extinction, anxiety and related defensive behaviours. Newly developed genetic and viral tools, optogenetics and advanced in vivo imaging techniques have now made it possible to characterize the activity, connectivity and function of specific cell types within complex neuronal circuits. Recent findings that have been made using these tools and techniques have provided mechanistic insights into the exquisite organization of the circuitry underlying internal defensive states. This Review focuses on studies that have used circuit-based approaches to gain a more detailed, and also more comprehensive and integrated, view on how the brain governs fear and anxiety and how it orchestrates adaptive defensive behaviours.
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Affiliation(s)
- Philip Tovote
- 1] Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. [2]
| | - Jonathan Paul Fadok
- 1] Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. [2]
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
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15
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Klenowski PM, Fogarty MJ, Belmer A, Noakes PG, Bellingham MC, Bartlett SE. Structural and functional characterization of dendritic arbors and GABAergic synaptic inputs on interneurons and principal cells in the rat basolateral amygdala. J Neurophysiol 2015; 114:942-57. [PMID: 26041829 DOI: 10.1152/jn.00824.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 06/02/2015] [Indexed: 11/22/2022] Open
Abstract
The basolateral amygdala (BLA) is a complex brain region associated with processing emotional states, such as fear, anxiety, and stress. Some aspects of these emotional states are driven by the network activity of synaptic connections, derived from both local circuitry and projections to the BLA from other regions. Although the synaptic physiology and general morphological characteristics are known for many individual cell types within the BLA, the combination of morphological, electrophysiological, and distribution of neurochemical GABAergic synapses in a three-dimensional neuronal arbor has not been reported for single neurons from this region. The aim of this study was to assess differences in morphological characteristics of BLA principal cells and interneurons, quantify the distribution of GABAergic neurochemical synapses within the entire neuronal arbor of each cell type, and determine whether GABAergic synaptic density correlates with electrophysiological recordings of inhibitory postsynaptic currents. We show that BLA principal neurons form complex dendritic arborizations, with proximal dendrites having fewer spines but higher densities of neurochemical GABAergic synapses compared with distal dendrites. Furthermore, we found that BLA interneurons exhibited reduced dendritic arbor lengths and spine densities but had significantly higher densities of putative GABAergic synapses compared with principal cells, which was correlated with an increased frequency of spontaneous inhibitory postsynaptic currents. The quantification of GABAergic connectivity, in combination with morphological and electrophysiological measurements of the BLA cell types, is the first step toward a greater understanding of how fear and stress lead to changes in morphology, local connectivity, and/or synaptic reorganization of the BLA.
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Affiliation(s)
- Paul M Klenowski
- Translational Research Institute and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Matthew J Fogarty
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia; and
| | - Arnauld Belmer
- Translational Research Institute and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Peter G Noakes
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia; and Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Mark C Bellingham
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia; and
| | - Selena E Bartlett
- Translational Research Institute and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia;
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16
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Glutamic acid decarboxylase 65: a link between GABAergic synaptic plasticity in the lateral amygdala and conditioned fear generalization. Neuropsychopharmacology 2014; 39:2211-20. [PMID: 24663011 PMCID: PMC4104340 DOI: 10.1038/npp.2014.72] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 12/25/2022]
Abstract
An imbalance of the gamma-aminobutyric acid (GABA) system is considered a major neurobiological pathomechanism of anxiety, and the amygdala is a key brain region involved. Reduced GABA levels have been found in anxiety patients, and genetic variations of glutamic acid decarboxylase (GAD), the rate-limiting enzyme of GABA synthesis, have been associated with anxiety phenotypes in both humans and mice. These findings prompted us to hypothesize that a deficiency of GAD65, the GAD isoform controlling the availability of GABA as a transmitter, affects synaptic transmission and plasticity in the lateral amygdala (LA), and thereby interferes with fear responsiveness. Results indicate that genetically determined GAD65 deficiency in mice is associated with (1) increased synaptic length and release at GABAergic connections, (2) impaired efficacy of GABAergic synaptic transmission and plasticity, and (3) reduced spillover of GABA to presynaptic GABAB receptors, resulting in a loss of the associative nature of long-term synaptic plasticity at cortical inputs to LA principal neurons. (4) In addition, training with high shock intensities in wild-type mice mimicked the phenotype of GAD65 deficiency at both the behavioral and synaptic level, indicated by generalization of conditioned fear and a loss of the associative nature of synaptic plasticity in the LA. In conclusion, GAD65 is required for efficient GABAergic synaptic transmission and plasticity, and for maintaining extracellular GABA at a level needed for associative plasticity at cortical inputs in the LA, which, if disturbed, results in an impairment of the cue specificity of conditioned fear responses typifying anxiety disorders.
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17
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Capogna M. GABAergic cell type diversity in the basolateral amygdala. Curr Opin Neurobiol 2014; 26:110-6. [PMID: 24486420 DOI: 10.1016/j.conb.2014.01.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/10/2013] [Accepted: 01/08/2014] [Indexed: 11/20/2022]
Abstract
Here I review the diversity of GABAergic neurons in the rodent basolateral amygdala (BLA). In spite of the recent identification of the role played by certain neurons of BLA in learning and memory of fear, the diversity of GABAergic neurons has not been fully explored. I describe analogies and differences between GABAergic neurons in BLA and cerebral cortex. Emphasis is given to a comprehensive functional, neurochemical and anatomical classification of GABAergic neuron types.
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Affiliation(s)
- Marco Capogna
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
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18
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Hadad-Ophir O, Albrecht A, Stork O, Richter-Levin G. Amygdala activation and GABAergic gene expression in hippocampal sub-regions at the interplay of stress and spatial learning. Front Behav Neurosci 2014; 8:3. [PMID: 24478650 PMCID: PMC3896990 DOI: 10.3389/fnbeh.2014.00003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/03/2014] [Indexed: 12/14/2022] Open
Abstract
Molecular processes in GABAergic local circuit neurons critically contribute to information processing in the hippocampus and to stress-induced activation of the amygdala. In the current study, we determined expression changes in GABA-related factors induced in subregions of the dorsal hippocampus as well as in the BLA of rats 5 h after spatial learning in a Morris water maze (MWM), using laser microdissection and quantitative real-time PCR. Spatial learning resulted in highly selective pattern of changes in hippocampal subregions: gene expression levels of neuropeptide Y (NPY) were reduced in the hilus of the dentate gyrus (DG), whereas somatostatin (SST) was increased in the stratum oriens (SO) of CA3. The GABA-synthesizing enzymes GAD65 and GAD67 as well as the neuropeptide cholecystokinin (CCK) were reduced in SO of CA1. In the BLA, expression of GAD65 and GAD67 were reduced compared to a handled Control group. These expression patterns were further compared to alterations in a group of rats that have been exposed to the water maze but were not provided with an invisible escape platform. In this Water Exposure group, no expression changes were observed in any of the hippocampal subregions, but a differential regulation of all selected target genes was evident in the BLA. These findings suggest that expression changes of GABAergic factors in the hippocampus are associated with spatial learning, while additional stress effects modulate expression alterations in the BLA. Indeed, while in both experimental groups plasma corticosterone (CORT) levels were enhanced, only Water Exposure stress activated the basolateral amygdala (BLA), as indicated by increased levels of phosphorylated ERK 1/2. Altered GABAergic function in the BLA may thus contribute to memory consolidation in the hippocampus, in relation to levels of stress and emotionality associated with the experience.
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Affiliation(s)
- Osnat Hadad-Ophir
- Sagol Department of Neurobiology, University of Haifa Haifa, Israel ; The Brain and Behavior Research Center, University of Haifa Haifa, Israel ; The Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel
| | - Anne Albrecht
- Sagol Department of Neurobiology, University of Haifa Haifa, Israel ; The Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel ; Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg Germany ; Center for Behavioral Brain Sciences Magdeburg, Germany
| | - Gal Richter-Levin
- Sagol Department of Neurobiology, University of Haifa Haifa, Israel ; The Brain and Behavior Research Center, University of Haifa Haifa, Israel ; The Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel
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19
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Sears RM, Schiff HC, LeDoux JE. Molecular Mechanisms of Threat Learning in the Lateral Nucleus of the Amygdala. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:263-304. [DOI: 10.1016/b978-0-12-420170-5.00010-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Orsini CA, Maren S. Neural and cellular mechanisms of fear and extinction memory formation. Neurosci Biobehav Rev 2012; 36:1773-802. [PMID: 22230704 PMCID: PMC3345303 DOI: 10.1016/j.neubiorev.2011.12.014] [Citation(s) in RCA: 321] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Revised: 12/16/2011] [Accepted: 12/23/2011] [Indexed: 02/08/2023]
Abstract
Over the course of natural history, countless animal species have evolved adaptive behavioral systems to cope with dangerous situations and promote survival. Emotional memories are central to these defense systems because they are rapidly acquired and prepare organisms for future threat. Unfortunately, the persistence and intrusion of memories of fearful experiences are quite common and can lead to pathogenic conditions, such as anxiety and phobias. Over the course of the last 30 years, neuroscientists and psychologists alike have attempted to understand the mechanisms by which the brain encodes and maintains these aversive memories. Of equal interest, though, is the neurobiology of extinction memory formation as this may shape current therapeutic techniques. Here we review the extant literature on the neurobiology of fear and extinction memory formation, with a strong focus on the cellular and molecular mechanisms underlying these processes.
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Affiliation(s)
- Caitlin A. Orsini
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109-1043, USA
| | - Stephen Maren
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109-1043, USA
- Department of Neuroscience Program, University of Michigan, Ann Arbor, MI, 48109-1043, USA
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21
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Johansen JP, Cain CK, Ostroff LE, LeDoux JE. Molecular mechanisms of fear learning and memory. Cell 2011; 147:509-24. [PMID: 22036561 DOI: 10.1016/j.cell.2011.10.009] [Citation(s) in RCA: 714] [Impact Index Per Article: 54.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Indexed: 01/08/2023]
Abstract
Pavlovian fear conditioning is a particularly useful behavioral paradigm for exploring the molecular mechanisms of learning and memory because a well-defined response to a specific environmental stimulus is produced through associative learning processes. Synaptic plasticity in the lateral nucleus of the amygdala (LA) underlies this form of associative learning. Here, we summarize the molecular mechanisms that contribute to this synaptic plasticity in the context of auditory fear conditioning, the form of fear conditioning best understood at the molecular level. We discuss the neurotransmitter systems and signaling cascades that contribute to three phases of auditory fear conditioning: acquisition, consolidation, and reconsolidation. These studies suggest that multiple intracellular signaling pathways, including those triggered by activation of Hebbian processes and neuromodulatory receptors, interact to produce neural plasticity in the LA and behavioral fear conditioning. Collectively, this body of research illustrates the power of fear conditioning as a model system for characterizing the mechanisms of learning and memory in mammals and potentially for understanding fear-related disorders, such as PTSD and phobias.
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Affiliation(s)
- Joshua P Johansen
- Center for Neural Science, New York University, New York, NY 10003, USA
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22
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Spampanato J, Polepalli J, Sah P. Interneurons in the basolateral amygdala. Neuropharmacology 2010; 60:765-73. [PMID: 21093462 DOI: 10.1016/j.neuropharm.2010.11.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/01/2010] [Accepted: 11/10/2010] [Indexed: 01/18/2023]
Abstract
The amygdala is a temporal lobe structure that is the center of emotion processing in the mammalian brain. Recent interest in the amygdala arises from its role in processing fear and the relationship of fear to human anxiety. The amygdaloid complex is divided into a number of subnuclei that have extensive intra and extra nuclear connections. In this review we discuss recent findings on the physiology and plasticity of inputs to interneurons in the basolateral amygdala, the primary input station. These interneurons are a heterogeneous group of cells that can be separated on immunohistochemical and electrophysiological grounds. Glutamatergic inputs to these interneurons form diverse types of excitatory synapses. This diversity is manifest in both the subunit composition of the underlying NMDA receptors as well as their ability to show plasticity. We discuss these differences and their relationship to fear learning. This article is part of a Special Issue entitled 'Synaptic Plasticity & Interneurons'.
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Affiliation(s)
- Jay Spampanato
- The Queensland Brain Institute, University of Queensland, QBI Building (79), St Lucia, QLD 4072, Australia.
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23
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Pape HC, Pare D. Plastic synaptic networks of the amygdala for the acquisition, expression, and extinction of conditioned fear. Physiol Rev 2010; 90:419-63. [PMID: 20393190 DOI: 10.1152/physrev.00037.2009] [Citation(s) in RCA: 756] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The last 10 years have witnessed a surge of interest for the mechanisms underlying the acquisition and extinction of classically conditioned fear responses. In part, this results from the realization that abnormalities in fear learning mechanisms likely participate in the development and/or maintenance of human anxiety disorders. The simplicity and robustness of this learning paradigm, coupled with the fact that the underlying circuitry is evolutionarily well conserved, make it an ideal model to study the basic biology of memory and identify genetic factors and neuronal systems that regulate the normal and pathological expressions of learned fear. Critical advances have been made in determining how modified neuronal functions upon fear acquisition become stabilized during fear memory consolidation and how these processes are controlled in the course of fear memory extinction. With these advances came the realization that activity in remote neuronal networks must be coordinated for these events to take place. In this paper, we review these mechanisms of coordinated network activity and the molecular cascades leading to enduring fear memory, and allowing for their extinction. We will focus on Pavlovian fear conditioning as a model and the amygdala as a key component for the acquisition and extinction of fear responses.
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Affiliation(s)
- Hans-Christian Pape
- Institute of Physiology, Westfaelische Wilhelms-University, Muenster, Germany; and Rutgers State University, Newark, New Jersey, USA.
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24
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Graebenitz S, Lesting J, Sosulina L, Seidenbecher T, Pape HC. Alteration of NMDA receptor-mediated synaptic interactions in the lateral amygdala associated with seizure activity in a mouse model of chronic temporal lobe epilepsy. Epilepsia 2010; 51:1754-62. [DOI: 10.1111/j.1528-1167.2010.02561.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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25
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Normal hearing is required for the emergence of long-lasting inhibitory potentiation in cortex. J Neurosci 2010; 30:331-41. [PMID: 20053914 DOI: 10.1523/jneurosci.4554-09.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Long-term synaptic plasticity is a putative mechanism for learning in adults. However, there is little understanding of how synaptic plasticity mechanisms develop or whether their maturation depends on experience. Since inhibitory synapses are particularly malleable to sensory stimulation, long-lasting potentiation of inhibitory synapses was characterized in auditory thalamocortical slices. Intracortical high-frequency electrical stimulation led to a 67% increase in inhibitory synaptic currents. In the absence of stimulation, inhibitory potentiation was induced by a brief exposure to exogenous brain-derived neurotrophic factor (BDNF). BDNF exposure occluded any additional potentiation by high-frequency afferent stimulation, suggesting that BDNF signaling is sufficient to account for inhibitory potentiation. Moreover, inhibitory potentiation was reduced significantly by extracellular application of a BDNF scavenger or by intracellular blockade of BDNF receptor [tropomyosin-related kinase B (TrkB)] signaling. In contrast, glutamatergic or GABAergic antagonists did not prevent the induction of inhibitory potentiation. Since BDNF and TrkB expression are influenced strongly by activity, we predicted that inhibitory potentiation would be diminished by manipulations that decrease central auditory activity, such as hearing loss. Two forms of hearing loss were examined: conductive hearing loss in which the cochleae are not damaged or sensorineural hearing loss in which both cochleae are removed. Both forms of hearing loss were found to reduce significantly the magnitude of inhibitory potentiation. These data indicate that early experience is necessary for the normal development of BDNF-mediated long-lasting inhibitory potentiation, which may be associated with perceptual deficits at later ages.
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26
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McCool BA, Christian DT, Diaz MR, Läck AK. Glutamate plasticity in the drunken amygdala: the making of an anxious synapse. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2010; 91:205-33. [PMID: 20813244 DOI: 10.1016/s0074-7742(10)91007-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Plasticity at glutamatergic synapses is believed to be the cellular correlate of learning and memory. Classic fear conditioning, for example, is dependent upon NMDA-type glutamate receptor activation in the lateral/basolateral amygdala followed by increased synaptic expression of AMPA-type glutamate receptors. This review provides an extensive comparison between the initiation and expression of glutamatergic plasticity during learning/memory and glutamatergic alterations associated with chronic ethanol exposure and withdrawal. The parallels between these neuro-adaptive processes suggest that long-term ethanol exposure might "chemically condition" amygdala-dependent fear/anxiety via the increased function of pre- and post-synaptic glutamate signaling.
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Affiliation(s)
- Brian A McCool
- Department of Physiology & Pharmcology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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27
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Ehrlich I, Humeau Y, Grenier F, Ciocchi S, Herry C, Lüthi A. Amygdala inhibitory circuits and the control of fear memory. Neuron 2009; 62:757-71. [PMID: 19555645 DOI: 10.1016/j.neuron.2009.05.026] [Citation(s) in RCA: 673] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Revised: 05/13/2009] [Accepted: 05/19/2009] [Indexed: 11/16/2022]
Abstract
Classical fear conditioning is a powerful behavioral paradigm that is widely used to study the neuronal substrates of learning and memory. Previous studies have clearly identified the amygdala as a key brain structure for acquisition and storage of fear memory traces. Whereas the majority of this work has focused on principal cells and glutamatergic transmission and its plasticity, recent studies have started to shed light on the intricate roles of local inhibitory circuits. Here, we review current understanding and emerging concepts of how local inhibitory circuits in the amygdala control the acquisition, expression, and extinction of conditioned fear at different levels.
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Affiliation(s)
- Ingrid Ehrlich
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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28
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Pan BX, Dong Y, Ito W, Yanagawa Y, Shigemoto R, Morozov A. Selective gating of glutamatergic inputs to excitatory neurons of amygdala by presynaptic GABAb receptor. Neuron 2009; 61:917-29. [PMID: 19324000 DOI: 10.1016/j.neuron.2009.01.029] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 12/01/2008] [Accepted: 01/29/2009] [Indexed: 12/12/2022]
Abstract
GABAb receptor (GABAbR)-mediated suppression of glutamate release is critical for limiting glutamatergic transmission across the central nervous system (CNS). Here we show that, upon tetanic stimulation of afferents to lateral amygdala, presynaptic GABAbR-mediated inhibition only occurs in glutamatergic inputs to principle neurons (PNs), not to interneurons (INs), despite the presence of GABAbR in terminals to both types of neurons. The selectivity is caused by differential local GABA accumulation; it requires GABA reuptake and parallels distinct spatial distributions of presynaptic GABAbR in terminals to PNs and INs. Moreover, GABAbR-mediated suppression of theta-burst-induced long-term potentiation (LTP) occurs only in the inputs to PNs, not to INs. Thus, target-cell-specific control of glutamate release by presynaptic GABAbR orchestrates the inhibitory dominance inside amygdala and might contribute to prevention of nonadaptive defensive behaviors.
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Affiliation(s)
- Bing-Xing Pan
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, National Institutes of Health, 35 Convent Drive, Bethesda, MD 20892, USA.
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29
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Jasnow AM, Ressler KJ, Hammack SE, Chhatwal JP, Rainnie DG. Distinct subtypes of cholecystokinin (CCK)-containing interneurons of the basolateral amygdala identified using a CCK promoter-specific lentivirus. J Neurophysiol 2009; 101:1494-506. [PMID: 19164102 DOI: 10.1152/jn.91149.2008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The basolateral amygdala (BLA) is critical for the formation of emotional memories. Little is known about the physiological properties of BLA interneurons, which can be divided into four subtypes based on their immunocytochemical profiles. Cholecystokinin (CCK) interneurons play critical roles in feedforward inhibition and behavioral fear responses. Evidence suggests that interneurons within a subgroup can display heterogeneous physiological properties. However, little is known about the physiological properties of CCK interneurons in the BLA and/or whether they represent a homogeneous or heterogeneous population. To address this question, we generated a lentivirus-expressing GFP under the control of the CCK promoter to identify CCK neurons in vivo. We combined this with whole cell patch-clamp recording techniques to examine the physiological properties of CCK-containing interneurons of the rat BLA. Here, we describe the physiological properties of 57 cells recorded in current-clamp mode; we used hierarchical cluster and discriminant function analysis to demonstrate that CCK interneurons can be segregated into three distinct subtypes (I, II, III) based on their passive and active membrane properties. Additionally, Type II neurons could be further separated into adapting and nonadapting types based on their rates of spike frequency adaptation. These data suggest that CCK interneurons of the BLA are a heterogeneous population and may be functionally distinct subpopulations that differentially contribute to the processing of emotionally salient stimuli.
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Affiliation(s)
- Aaron M Jasnow
- Department of Psychiatry and Behavioral Sciences, Center for Behavioral Neuroscience, Yerkes Research Center, Emory University School of Medicine, Atlanta, Georgia, USA.
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30
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Bergado-Acosta JR, Sangha S, Narayanan RT, Obata K, Pape HC, Stork O. Critical role of the 65-kDa isoform of glutamic acid decarboxylase in consolidation and generalization of Pavlovian fear memory. Learn Mem 2008; 15:163-71. [PMID: 18323571 DOI: 10.1101/lm.705408] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Evidence suggests that plasticity of the amygdalar and hippocampal GABAergic system is critical for fear memory formation. In this study we investigated in wild-type and genetically manipulated mice the role of the activity-dependent 65-kDa isozyme of glutamic acid decarboxylase (GAD65) in the consolidation and generalization of conditioned fear. First, we demonstrate a transient reduction of GAD65 gene expression in the dorsal hippocampus (6 h post training) and in the basolateral complex of the amygdala (24 h post training) during distinct phases of fear memory consolidation. Second, we show that targeted ablation of the GAD65 gene in Gad65(-/-) mice results in a pronounced context-independent, intramodal generalization of auditory fear memory during long-term (24 h or 14 d) but not short-term (30 min) memory retrieval. The temporal specificity of both gene regulation and memory deficits in Gad65 mutant mice suggests that GAD65-mediated GABA synthesis is critical for the consolidation of stimulus-specific fear memory. This function appears to involve a modulation of neural activity patterns in the amygdalo-hippocampal pathway as indicated by a reduction in theta frequency synchronization between the amygdala and hippocampus of Gad65(-/-) mice during the expression of generalized fear memory.
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Affiliation(s)
- Jorge R Bergado-Acosta
- Institute for Physiology, Otto-von-Guericke University Magdeburg, D-39120 Magdeburg, Germany
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31
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Thompson JV, Sullivan RM, Wilson DA. Developmental emergence of fear learning corresponds with changes in amygdala synaptic plasticity. Brain Res 2008; 1200:58-65. [PMID: 18295751 DOI: 10.1016/j.brainres.2008.01.057] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Revised: 01/10/2008] [Accepted: 01/12/2008] [Indexed: 12/24/2022]
Abstract
Mother-infant attachment is facilitated in altricial rodents through unique neural mechanisms that include impaired neonatal fear conditioning until the time that pups first begin to leave the nest (sensitive period). Here, we confirmed the developmental emergence of odor fear conditioning in neonatal rat pups, and examined synaptic plasticity of inputs to the basolateral amygdala in vitro. Coronal slices through the amygdala were obtained from sensitive (<10 days) and post-sensitive (>10, <19 days) period pups. Field potentials were recorded in the basolateral amygdala in response to stimulation of either the external capsule (neocortical inputs) or fibers from the cortical nucleus of the amygdala (olfactory inputs). The effects of tetanic stimulation were examined in each pathway. In both pathways, tetanic stimulation induce significant long-term synaptic plasticity in post-sensitive period pups, but no significant plasticity in sensitive period pups incapable of learning odor aversions. GABA(A) receptor blockade in post-sensitive period slices reverts synaptic plasticity to sensitive period characteristics. The results suggest that sensitive period deficits in fear conditioning may be related to impaired amygdala synaptic plasticity and the immature state of GABAergic inhibition and/or its modulation in the neonatal amygdala.
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Affiliation(s)
- Jason V Thompson
- Neurobehavioral Institute, Department of Zoology, University of Oklahoma, OK 73019, USA
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32
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Learning-related long-term potentiation of inhibitory synapses in the cerebellar cortex. Proc Natl Acad Sci U S A 2008; 105:769-74. [PMID: 18184813 DOI: 10.1073/pnas.0706342105] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Despite the widespread distribution of inhibitory synapses throughout the central nervous system, plasticity of inhibitory synapses related to associative learning has never been reported. In the cerebellum, the neural correlate of fear memory is provided by a long-term potentiation (LTP) of the excitatory synapse between the parallel fibers (PFs) and the Purkinje cell (PC). In this article, we provide evidence that inhibitory synapses in the cerebellar cortex also are affected by fear conditioning. Whole-cell patch-clamp recordings of spontaneous and miniature GABAergic events onto the PC show that the frequency but not the amplitude of these events is significantly greater up to 24 h after the conditioning. Adequate levels of excitation and inhibition are required to maintain the temporal fidelity of a neuronal network. Such fidelity can be evaluated by determining the time window for multiple input coincidence detection. We found that, after fear learning, PCs are able to integrate excitatory inputs with greater probability within short delays, but the width of the whole window is unchanged. Therefore, excitatory LTP provides a more effective detection, and inhibitory potentiation serves to maintain the time resolution of the system.
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