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Herrera-Rivero M, Bohn L, Witten A, Jüngling K, Kaiser S, Richter SH, Stoll M, Sachser N. Transcriptional profiles in the mouse amygdala after a cognitive judgment bias test largely depend on the genotype. Front Mol Neurosci 2022; 15:1025389. [DOI: 10.3389/fnmol.2022.1025389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/04/2022] [Indexed: 12/03/2022] Open
Abstract
Background: The amygdala is crucial for emotional cognitive processing. Affective or emotional states can bias cognitive processes, including attention, memory, and decision-making. This can result in optimistic or pessimistic behaviors that are partially driven by the activation of the amygdala. The resulting emotional cognitive bias is a common feature of anxiety and mood disorders, both of which are interactively influenced by genetic and environmental factors. It is also known that emotional cognitive biases can be influenced by environmental factors. However, little is known about the effects of genetics and/or gene-environment interactions on emotional cognitive biases. We investigated the effects of the genetic background and environmental enrichment on the transcriptional profiles of the mouse amygdala following a well-established cognitive bias test.Methods: Twenty-four female C57BL/6J and B6D2F1N mice were housed either in standard (control) conditions or in an enriched environment. After appropriate training, the cognitive bias test was performed on 19 mice that satisfactorily completed the training scheme to assess their responses to ambiguous cues. This allowed us to calculate an “optimism score” for each mouse. Subsequently, we dissected the anterior and posterior portions of the amygdala to perform RNA-sequencing for differential expression and other statistical analyses.Results: In general, we found only minor changes in the amygdala’s transcriptome associated with the levels of optimism in our mice. In contrast, we observed wide molecular effects of the genetic background in both housing environments. The C57BL/6J animals showed more transcriptional changes in response to enriched environments than the B6D2F1N mice. We also generally found more dysregulated genes in the posterior than in the anterior portion of the amygdala. Gene set overrepresentation analyses consistently implicated cellular metabolic responses and immune processes in the differences observed between mouse strains, while processes favoring neurogenesis and neurotransmission were implicated in the responses to environmental enrichment. In a correlation analysis, lipid metabolism in the anterior amygdala was suggested to influence the levels of optimism.Conclusions: Our observations underscore the importance of selecting appropriate animal models when performing molecular studies of affective conditions or emotional states, and suggest an important role of immune and stress responses in the genetic component of emotion regulation.
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Kida E, Walus M, Albertini G, Golabek AA. Long-term voluntary running modifies the levels of proteins of the excitatory/inhibitory system and reduces reactive astrogliosis in the brain of Ts65Dn mouse model for Down syndrome. Brain Res 2021; 1766:147535. [PMID: 34043998 DOI: 10.1016/j.brainres.2021.147535] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 09/30/2022]
Abstract
We showed previously that voluntary long-term running improved cognition and motor skills, but in an age-dependent manner, in the Ts65Dn mouse model for Down syndrome (DS). Presently, we investigated the effect of running on the levels of some key proteins of the excitatory/inhibitory system, which is impaired in the trisomic brain, and on astroglia, a vital component of this system. Ts65Dn mice had free access to a running wheel for 9-13 months either from weaning or from the age of 7 months. Sedentary Ts65Dn mice served as controls. We found that running modified the levels of four of the seven proteins we tested that are associated with the glutamatergic/GABA-ergic system. Thus, Ts65Dn runners demonstrated increased levels of glutamine synthetase and metabotropic glutamate receptor 1 and decreased levels of glutamate transporter 1 and glutamic acid decarboxylase 65 (GAD65) versus sedentary mice, but of metabotropic glutamate receptor 1 and GAD65 only in the post-weaning cohort. GAD67, ionotropic N-methyl-D-aspartate type receptor subunit 1, and GABAAα5 receptors' levels were similar in runners and sedentary animals. The number of glial fibrillary acidic protein (GFAP)-positive astrocytes and the levels of GFAP were significantly reduced in runners relative to sedentary mice. Our study provides new insight into the mechanisms underlying the beneficial effect of voluntary, sustained running on function of the trisomic brain by identifying the involvement of proteins associated with glutamatergic and GABAergic systems and reduction in reactive astrogliosis.
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Affiliation(s)
- Elizabeth Kida
- Department of Developmental Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Marius Walus
- Department of Developmental Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Giorgio Albertini
- Child Development Department, IRCCS San Raffaele Pisana, Rome and San Raffaele Cassino, Italy
| | - Adam A Golabek
- Department of Developmental Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA.
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3
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Fujihara K, Sato T, Miyasaka Y, Mashimo T, Yanagawa Y. Genetic deletion of the 67-kDa isoform of glutamate decarboxylase alters conditioned fear behavior in rats. FEBS Open Bio 2020; 11:340-353. [PMID: 33325157 PMCID: PMC7876494 DOI: 10.1002/2211-5463.13065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/24/2020] [Accepted: 12/14/2020] [Indexed: 12/31/2022] Open
Abstract
The GABAergic system is thought to play an important role in the control of cognition and emotion, such as fear, and is related to the pathophysiology of psychiatric disorders. For example, the expression of the 67‐kDa isoform of glutamate decarboxylase (GAD67), a GABA‐producing enzyme, is downregulated in the postmortem brains of patients with major depressive disorder and schizophrenia. However, knocking out the Gad1 gene, which encodes GAD67, is lethal in mice, and thus, the association between Gad1 and cognitive/emotional functions is unclear. We recently developed Gad1 knockout rats and found that some of them can grow into adulthood. Here, we performed fear‐conditioning tests in adult Gad1 knockout rats to assess the impact of the loss of Gad1 on fear‐related behaviors and the formation of fear memory. In a protocol assessing both cued and contextual memory, Gad1 knockout rats showed a partial antiphase pattern of freezing during training and significantly excessive freezing during the contextual test compared with wild‐type rats. However, Gad1 knockout rats did not show any synchronous increase in freezing with auditory tones in the cued test. On the other hand, in a contextual memory specialized protocol, Gad1 knockout rats exhibited comparable freezing behavior to wild‐type rats, while their fear extinction was markedly impaired. These results suggest that GABA synthesis by GAD67 has differential roles in cued and contextual fear memory.
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Affiliation(s)
- Kazuyuki Fujihara
- Departments of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma University, Maebashi, Japan.,Department of Psychiatry and Neuroscience, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Takumi Sato
- Departments of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Yoshiki Miyasaka
- Institute of Experimental Animal Sciences, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tomoji Mashimo
- Laboratory Animal Research Center, Institute of Medical Science, the University of Tokyo, Japan
| | - Yuchio Yanagawa
- Departments of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma University, Maebashi, Japan
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4
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Sangha S, Diehl MM, Bergstrom HC, Drew MR. Know safety, no fear. Neurosci Biobehav Rev 2020; 108:218-230. [PMID: 31738952 PMCID: PMC6981293 DOI: 10.1016/j.neubiorev.2019.11.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 09/27/2019] [Accepted: 11/11/2019] [Indexed: 02/08/2023]
Abstract
Every day we are bombarded by stimuli that must be assessed for their potential for harm or benefit. Once a stimulus is learned to predict harm, it can elicit fear responses. Such learning can last a lifetime but is not always beneficial for an organism. For an organism to thrive in its environment, it must know when to engage in defensive, avoidance behaviors and when to engage in non-defensive, approach behaviors. Fear should be suppressed in situations that are not dangerous: when a novel, innocuous stimulus resembles a feared stimulus, when a feared stimulus no longer predicts harm, or when there is an option to avoid harm. A cardinal feature of anxiety disorders is the inability to suppress fear adaptively. In PTSD, for instance, learned fear is expressed inappropriately in safe situations and is resistant to extinction. In this review, we discuss mechanisms of suppressing fear responses during stimulus discrimination, fear extinction, and active avoidance, focusing on the well-studied tripartite circuit consisting of the amygdala, medial prefrontal cortex and hippocampus.
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Affiliation(s)
- Susan Sangha
- Department of Psychological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA.
| | - Maria M Diehl
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, USA.
| | - Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, NY, USA.
| | - Michael R Drew
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.
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Kasugai Y, Vogel E, Hörtnagl H, Schönherr S, Paradiso E, Hauschild M, Göbel G, Milenkovic I, Peterschmitt Y, Tasan R, Sperk G, Shigemoto R, Sieghart W, Singewald N, Lüthi A, Ferraguti F. Structural and Functional Remodeling of Amygdala GABAergic Synapses in Associative Fear Learning. Neuron 2019; 104:781-794.e4. [PMID: 31543297 DOI: 10.1016/j.neuron.2019.08.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/09/2019] [Accepted: 08/07/2019] [Indexed: 01/12/2023]
Abstract
Associative learning is thought to involve different forms of activity-dependent synaptic plasticity. Although previous studies have mostly focused on learning-related changes occurring at excitatory glutamatergic synapses, we found that associative learning, such as fear conditioning, also entails long-lasting functional and structural plasticity of GABAergic synapses onto pyramidal neurons of the murine basal amygdala. Fear conditioning-mediated structural remodeling of GABAergic synapses was associated with a change in mIPSC kinetics and an increase in the fraction of synaptic benzodiazepine-sensitive (BZD) GABAA receptors containing the α2 subunit without altering the intrasynaptic distribution and overall amount of BZD-GABAA receptors. These structural and functional synaptic changes were partly reversed by extinction training. These findings provide evidence that associative learning, such as Pavlovian fear conditioning and extinction, sculpts inhibitory synapses to regulate inhibition of active neuronal networks, a process that may tune amygdala circuit responses to threats.
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Affiliation(s)
- Yu Kasugai
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Elisabeth Vogel
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland
| | - Heide Hörtnagl
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Sabine Schönherr
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Enrica Paradiso
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Markus Hauschild
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck 6020, Austria
| | - Georg Göbel
- Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Ivan Milenkovic
- Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Yvan Peterschmitt
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria; Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Ramon Tasan
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck 6020, Austria
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland; University of Basel, Basel, Switzerland
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria.
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Gley K, Murani E, Haack F, Trakooljul N, Zebunke M, Puppe B, Wimmers K, Ponsuksili S. Haplotypes of coping behavior associated QTL regions reveal distinct transcript profiles in amygdala and hippocampus. Behav Brain Res 2019; 372:112038. [PMID: 31202863 DOI: 10.1016/j.bbr.2019.112038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/06/2019] [Accepted: 06/12/2019] [Indexed: 12/15/2022]
Abstract
Stress response and coping behavior in pigs are largely shaped by hypothalamic-pituitary-adrenal axis and sympatho-adrenomedullary system action. However, the dynamic interaction between amygdala and hippocampus crucially modulates the behavioral response towards significant emotional events. While this functional relationship is well documented, the molecular underpinnings still remain insufficiently understood. Our study used transcriptome profiling of porcine amygdala and hippocampus to identify molecular pathways that are differentially activated depending on the haplotype of a significantly coping behavior-associated region on pig chromosome 12 (SSC12). The pigs were classified into two groups based on the haplotype information of this QTL-region discovered in our previous genome-wide association study. Ten each of high- (HR) and low- (LR) reactive pigs (n = 20) were selected for differential gene expression analysis and weighted gene co-expression analysis with subsequent pathway analysis. Differentially expressed genes identified in the amygdala include SELL, CXCR7 and NTS, while TRAF3, PTGS2 and CFI were detected in the hippocampus indicating a role of neuroinflammation and immunological processes. Pathway analysis revealed IL-8 signaling, NF-κB signaling, glutamate and GABA metabolism, glucocorticoid receptor signaling and chemokine signaling in the amygdala and ephrin receptor signaling, as well as NF-κB signaling in the hippocampus. We discovered candidate genes in regions detected by genome-wide association study including ARRB2, ADRBK2, THRB, NEK7 and ACVR2B, which relate to dopaminergic and other monoaminergic neurotransmitter systems, neuroimmunomodulation, neuroinflammation and GABA-ergic neurotransmission. These findings provide insights into the molecular underpinning of divergent coping behavior and associated haplotypes in limbic forebrain system in pig.
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Affiliation(s)
- Kevin Gley
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany
| | - Eduard Murani
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany
| | - Fiete Haack
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany
| | - Nares Trakooljul
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany
| | - Manuela Zebunke
- Leibniz Institute of Farm Animal Biology (FBN), Institute of Genetics and Biometry, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany; Leibniz Institute of Farm Animal Biology (FBN), Institute for Behavioral Physiology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
| | - Birger Puppe
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Behavioral Physiology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
| | - Klaus Wimmers
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany
| | - Siriluck Ponsuksili
- Leibniz Institute of Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany.
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Sex differences in learned fear expression and extinction involve altered gamma oscillations in medial prefrontal cortex. Neurobiol Learn Mem 2016; 135:66-72. [PMID: 27344940 DOI: 10.1016/j.nlm.2016.06.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/06/2016] [Accepted: 06/21/2016] [Indexed: 11/22/2022]
Abstract
Sex differences in learned fear expression and extinction involve the medial prefrontal cortex (mPFC). We recently demonstrated that enhanced learned fear expression during auditory fear extinction and its recall is linked to persistent theta activation in the prelimbic (PL) but not infralimbic (IL) cortex of female rats. Emerging evidence indicates that gamma oscillations in mPFC are also implicated in the expression and extinction of learned fear. Therefore we re-examined our in vivo electrophysiology data and found that females showed persistent PL gamma activation during extinction and a failure of IL gamma activation during extinction recall. Altered prefrontal gamma oscillations thus accompany sex differences in learned fear expression and its extinction. These findings are relevant for understanding the neural basis of post-traumatic stress disorder, which is more prevalent in women and involves impaired extinction and mPFC dysfunction.
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8
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Sangha S. Plasticity of Fear and Safety Neurons of the Amygdala in Response to Fear Extinction. Front Behav Neurosci 2015; 9:354. [PMID: 26733838 PMCID: PMC4689868 DOI: 10.3389/fnbeh.2015.00354] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/06/2015] [Indexed: 01/29/2023] Open
Abstract
Fear inhibition learning induces plasticity and remodeling of circuits within the amygdala. Most studies examine these changes in nondiscriminative fear conditioning paradigms. Using a discriminative fear, safety, and reward conditioning task, Sangha et al. (2013) have previously reported several neural microcircuits within the basal amygdala (BA) which discriminate among these cues, including a subpopulation of neurons responding selectively to a safety cue and not a fear cue. Here, the hypothesis that these "safety" neurons isolated during discriminative conditioning are biased to become fear cue responsive as a result of extinction, when fear behavior diminishes, was tested. Although 41% of "safety" neurons became fear cue responsive as a result of extinction, the data revealed that there was no bias for these neurons to become preferentially responsive during fear extinction compared to the other identified subgroups. In addition to the plasticity seen in the "safety" neurons, 44% of neurons unresponsive to either the fear cue or safety cue during discriminative conditioning became fear cue responsive during extinction. Together these emergent responses to the fear cue as a result of extinction support the hypothesis that new learning underlies extinction. In contrast, 47% of neurons responsive to the fear cue during discriminative conditioning became unresponsive to the fear cue during extinction. These findings are consistent with a suppression of neural responding mediated by inhibitory learning, or, potentially, by direct unlearning. Together, the data support extinction as an active process involving both gains and losses of responses to the fear cue and suggests the final output of the integrated BA circuit in influencing fear behavior is a balance of excitation and inhibition, and perhaps reversal of learning-induced changes.
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Affiliation(s)
- Susan Sangha
- Department of Psychological Sciences, Purdue UniversityWest Lafayette, IN, USA; Ernest Gallo Clinic and Research Center, University of CaliforniaSan Francisco, Emeryville, CA, USA
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9
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Almeida-Suhett CP, Prager EM, Pidoplichko V, Figueiredo TH, Marini AM, Li Z, Eiden LE, Braga MF. GABAergic interneuronal loss and reduced inhibitory synaptic transmission in the hippocampal CA1 region after mild traumatic brain injury. Exp Neurol 2015; 273:11-23. [DOI: 10.1016/j.expneurol.2015.07.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/24/2015] [Accepted: 07/30/2015] [Indexed: 01/07/2023]
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10
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Jüngling K, Lange MD, Szkudlarek HJ, Lesting J, Erdmann FS, Doengi M, Kügler S, Pape HC. Increased GABAergic Efficacy of Central Amygdala Projections to Neuropeptide S Neurons in the Brainstem During Fear Memory Retrieval. Neuropsychopharmacology 2015; 40:2753-63. [PMID: 25936641 PMCID: PMC4864651 DOI: 10.1038/npp.2015.125] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/16/2015] [Accepted: 04/24/2015] [Indexed: 01/26/2023]
Abstract
The canonical view on the central amygdala has evolved from a simple output station towards a highly organized microcircuitry, in which types of GABAergic neurons in centrolateral (CeL) and centromedial (CeM) subnuclei regulate fear expression and generalization. How these specific neuronal populations are connected to extra-amygdaloid target regions remains largely unknown. Here we show in mice that a subpopulation of GABAergic CeL and CeM neurons projects monosynaptically to brainstem neurons expressing neuropeptide S (NPS). The CeL neurons are PKCδ-negative and are activated during conditioned fear. During fear memory retrieval, the efficacy of this GABAergic influence on NPS neurons is enhanced. Moreover, a large proportion of these neurons (~50%) contain prodynorphin and somatostatin, two neuropeptides inhibiting NPS neurons. We conclude that CeL and CeM neurons inhibit NPS neurons in the brainstem by GABA release and that efficacy of this connection is strengthened upon fear memory retrieval. Thereby, this pathway provides a possible feedback mechanism between amygdala and brainstem routes involved in fear and stress coping.
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Affiliation(s)
- Kay Jüngling
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany,Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, Münster D-48149, Germany. E-mail: or
| | - Maren D Lange
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Hanna J Szkudlarek
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Jörg Lesting
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Frank S Erdmann
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Michael Doengi
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Sebastian Kügler
- Department of Neurology, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Universitätsmedizin Göttingen, Göttingen, Germany
| | - Hans-Christian Pape
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany,Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, Münster D-48149, Germany. E-mail: or
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11
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Müller I, Çalışkan G, Stork O. The GAD65 knock out mouse - a model for GABAergic processes in fear- and stress-induced psychopathology. GENES BRAIN AND BEHAVIOR 2015; 14:37-45. [PMID: 25470336 DOI: 10.1111/gbb.12188] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/16/2022]
Abstract
The γ-amino butyric acid (GABA) synthetic enzyme glutamic acid decarboxylase (GAD)65 is critically involved in the activity-dependent regulation of GABAergic inhibition in the central nervous system. It is also required for the maturation of the GABAergic system during adolescence, a phase that is critical for the development of several neuropsychiatric diseases. Mice bearing a null mutation of the GAD65 gene develop hyperexcitability of the amygdala and hippocampus, and a phenotype of increased anxiety and pathological fear memory reminiscent of posttraumatic stress disorder. Although genetic association of GAD65 in human has not yet been reported, these findings are in line with observations of reduced GABAergic function in these brain regions of anxiety disorder patients. The particular value of GAD65(-/-) mice thus lies in modeling the effects of reduced GABAergic function in the mature nervous system. The expression of GAD65 and a second GAD isozyme, GAD67, are differentially regulated in response to stress in limbic brain areas suggesting that by controlling GABAergic inhibition these enzymes determine the vulnerability for the development of pathological anxiety and other stress-induced phenotypes. In fact, we could recently show that GAD65 haplodeficiency, which results in delayed postnatal increase of GABA levels, provides resilience to juvenile-stress-induced anxiety to GAD65(+/-) mice thus foiling the increased fear and anxiety in homozygous GAD65(-/-) mice.
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Affiliation(s)
- Iris Müller
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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12
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Melzer N, Budde T, Stork O, Meuth SG. Limbic Encephalitis: Potential Impact of Adaptive Autoimmune Inflammation on Neuronal Circuits of the Amygdala. Front Neurol 2015; 6:171. [PMID: 26284026 PMCID: PMC4522870 DOI: 10.3389/fneur.2015.00171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/20/2015] [Indexed: 12/31/2022] Open
Abstract
Limbic encephalitis is characterized by adaptive autoimmune inflammation of the gray matter structures of the limbic system. It has recently been identified as a major cause of temporal lobe epilepsy accompanied by progressive declarative – mainly episodic – memory disturbance as well as a variety of rather poorly defined emotional and behavioral changes. While autoimmune inflammation of the hippocampus is likely to be responsible for declarative memory disturbance, consequences of autoimmune inflammation of the amygdala are largely unknown. The amygdala is central for the generation of adequate homoeostatic behavioral responses to emotionally significant external stimuli following processing in a variety of parallel neuronal circuits. Here, we hypothesize that adaptive cellular and humoral autoimmunity may target and modulate distinct inhibitory or excitatory neuronal networks within the amygdala, and thereby strongly impact processing of emotional stimuli and corresponding behavioral responses. This may explain some of the rather poorly understood neuropsychiatric symptoms in limbic encephalitis.
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Affiliation(s)
- Nico Melzer
- Department of Neurology, University of Münster , Münster , Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster , Münster , Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg , Magdeburg , Germany
| | - Sven G Meuth
- Department of Neurology, University of Münster , Münster , Germany ; Department of Neuropathophysiology, Institute of Physiology I, University of Münster , Münster , Germany
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13
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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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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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Trouche S, Sasaki JM, Tu T, Reijmers LG. Fear extinction causes target-specific remodeling of perisomatic inhibitory synapses. Neuron 2013; 80:1054-65. [PMID: 24183705 DOI: 10.1016/j.neuron.2013.07.047] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2013] [Indexed: 10/26/2022]
Abstract
A more complete understanding of how fear extinction alters neuronal activity and connectivity within fear circuits may aid in the development of strategies to treat human fear disorders. Using a c-fos-based transgenic mouse, we found that contextual fear extinction silenced basal amygdala (BA) excitatory neurons that had been previously activated during fear conditioning. We hypothesized that the silencing of BA fear neurons was caused by an action of extinction on BA inhibitory synapses. In support of this hypothesis, we found extinction-induced target-specific remodeling of BA perisomatic inhibitory synapses originating from parvalbumin and cholecystokinin-positive interneurons. Interestingly, the predicted changes in the balance of perisomatic inhibition matched the silent and active states of the target BA fear neurons. These observations suggest that target-specific changes in perisomatic inhibitory synapses represent a mechanism through which experience can sculpt the activation patterns within a neural circuit.
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Affiliation(s)
- Stéphanie Trouche
- Department of Neuroscience, School of Medicine, Tufts University, Boston, MA 02111, USA.
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He Z, Cui L, He B, Ferguson SA, Paule MG. A common genetic mechanism underlying susceptibility to posttraumatic stress disorder. World J Neurol 2013; 3:14-24. [DOI: 10.5316/wjn.v3.i3.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/27/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
We hypothesize that susceptibility to post-traumatic stress disorder (PTSD) may be determined in part by aberrant microtubule-associated protein tau expression in neurons of critical brain structures. The following lines of evidence support this hypothesis. First, epidemiologic data suggest the involvement of genetic factors in the susceptibility to PTSD. Second, the common features of both abnormal tau expression and PTSD include amygdalar and hippocampal atrophy, upregulation of norepinephrine biosynthetic capacity in the surviving locus coeruleus neurons and dysfunction of N-methyl-D-aspartate-receptors. Finally, our experiments using rTg4510 mice, a model that over-expresses human mutant tau and develops age-dependent tauopathy, demonstrate that these animals display circling behavior thought to be related to states of anxiety. To detect the potential molecular mechanisms underlying PTSD episodes, laser-assisted/capture microdissection can be used with microarray analysis as an alternative approach to identify changes in gene expression in excitatory and/or inhibitory neurons in critical brain structures (i.e., hippocampus and amygdala) in response to the onset of PTSD.
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