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Arora I, Mal P, Arora P, Paul A, Kumar M. GABAergic implications in anxiety and related disorders. Biochem Biophys Res Commun 2024; 724:150218. [PMID: 38865810 DOI: 10.1016/j.bbrc.2024.150218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/05/2024] [Accepted: 06/02/2024] [Indexed: 06/14/2024]
Abstract
Evidence indicates that anxiety disorders arise from an imbalance in the functioning of brain circuits that govern the modulation of emotional responses to possibly threatening stimuli. The circuits under consideration in this context include the amygdala's bottom-up activity, which signifies the existence of stimuli that may be seen as dangerous. Moreover, these circuits encompass top-down regulatory processes that originate in the prefrontal cortex, facilitating the communication of the emotional significance associated with the inputs. Diverse databases (e.g., Pubmed, ScienceDirect, Web of Science, Google Scholar) were searched for literature using a combination of different terms e.g., "anxiety", "stress", "neuroanatomy", and "neural circuits", etc. A decrease in GABAergic activity is present in both anxiety disorders and severe depression. Research on cerebral functional imaging in depressive individuals has shown reduced levels of GABA within the cortical regions. Additionally, animal studies demonstrated that a reduction in the expression of GABAA/B receptors results in a behavioral pattern resembling anxiety. The amygdala consists of inhibitory networks composed of GABAergic interneurons, responsible for modulating anxiety responses in both normal and pathological conditions. The GABAA receptor has allosteric sites (e.g., α/γ, γ/β, and α/β) which enable regulation of neuronal inhibition in the amygdala. These sites serve as molecular targets for anxiolytic medications such as benzodiazepine and barbiturates. Alterations in the levels of naturally occurring regulators of these allosteric sites, along with alterations to the composition of the GABAA receptor subunits, could potentially act as mechanisms via which the extent of neuronal inhibition is diminished in pathological anxiety disorders.
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Affiliation(s)
- Indu Arora
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Pankaj Mal
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Poonam Arora
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Anushka Paul
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Manish Kumar
- Chitkara College of Pharmacy, Chitkara University, Punjab, India.
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2
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Kelly TJ, Bonniwell EM, Mu L, Liu X, Hu Y, Friedman V, Yu H, Su W, McCorvy JD, Liu QS. Psilocybin analog 4-OH-DiPT enhances fear extinction and GABAergic inhibition of principal neurons in the basolateral amygdala. Neuropsychopharmacology 2024; 49:854-863. [PMID: 37752222 PMCID: PMC10948882 DOI: 10.1038/s41386-023-01744-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/08/2023] [Accepted: 09/12/2023] [Indexed: 09/28/2023]
Abstract
Psychedelics such as psilocybin show great promise for the treatment of depression and PTSD, but their long duration of action poses practical limitations for patient access. 4-OH-DiPT is a fast-acting and shorter-lasting derivative of psilocybin. Here we characterized the pharmacological profile of 4-OH-DiPT and examined its impact on fear extinction learning as well as a potential mechanism of action. First, we profiled 4-OH-DiPT at all 12 human 5-HT GPCRs. 4-OH-DiPT showed strongest agonist activity at all three 5-HT2A/2B/2C receptors with near full agonist activity at 5-HT2A. Notably, 4-OH-DiPT had comparable activity at mouse and human 5-HT2A/2B/2C receptors. In a fear extinction paradigm, 4-OH-DiPT significantly reduced freezing responses to conditioned cues in a dose-dependent manner with a greater potency in female mice than male mice. Female mice that received 4-OH-DiPT before extinction training had reduced avoidance behaviors several days later in the light dark box, elevated plus maze and novelty-suppressed feeding test compared to controls, while male mice did not show significant differences. 4-OH-DiPT produced robust increases in spontaneous inhibitory postsynaptic currents (sIPSCs) in basolateral amygdala (BLA) principal neurons and action potential firing in BLA interneurons in a 5-HT2A-dependent manner. RNAscope demonstrates that Htr2a mRNA is expressed predominantly in BLA GABA interneurons, Htr2c mRNA is expressed in both GABA interneurons and principal neurons, while Htr2b mRNA is absent in the BLA. Our findings suggest that 4-OH-DiPT activates BLA interneurons via the 5-HT2A receptor to enhance GABAergic inhibition of BLA principal neurons, which provides a potential mechanism for suppressing learned fear.
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Affiliation(s)
- Thomas J Kelly
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Emma M Bonniwell
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Lianwei Mu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Xiaojie Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ying Hu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Vladislav Friedman
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Hao Yu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Wantang Su
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - John D McCorvy
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
| | - Qing-Song Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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Makarov M, Sysoev YI, Agafonova O, Prikhodko VA, Korkotian E, Okovityi SV. Color-Coding Method Reveals Enhancement of Stereotypic Locomotion by Phenazepam in Rat Open Field Test. Brain Sci 2023; 13:brainsci13030408. [PMID: 36979218 PMCID: PMC10046075 DOI: 10.3390/brainsci13030408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/03/2023] Open
Abstract
One of the most important tasks in neuroscience is the search for theoretical foundations for the development of methods for diagnosing and treating neurological pathology, and for assessing the effect of pharmacological drugs on the nervous system. Specific behavioral changes associated with exposure to systemic influences have been invisible to the human eye for a long time. A similar pattern of changes is characteristic of phenazepam, a drug with a wide range of effects on the brain. In this study, we used a color-coding method, which consists of combining three time positions in one image, the present (0 s), the near future (0.33 s) and the far future (1.6 s). This method made it possible to identify movement patterns, such as the initialization of ahead movements, side turns and 180° turns (back), and also to determine the degree of predictability of future movements. The obtained data revealed a decrease in the number of turns to the sides while maintaining ahead movement, as well as an increase in the predictability of movements in rats under the influence of phenazepam. Thus, sedative doses of phenazepam do not exhibit general depression of brain functions, but the inhibition of specific centers, including the medial prefrontal cortex and postsubiculum, which are involved in stereotypic locomotive behavior.
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Affiliation(s)
- Mark Makarov
- Faculty of Biology, Perm State University, 614068 Perm, Russia
| | - Yuri I. Sysoev
- Department of Pharmacology and Clinical Pharmacology, Saint Petersburg State Chemical and Pharmaceutical University, 197022 Saint Petersburg, Russia
- Laboratory of Neuroprosthetics, Institute of Translational Biomedicine, Saint Petersburg State University, 199034 Saint Petersburg, Russia
- I.P. Pavlov Institute of Physiology of the Russian Academy of Sciences, 199034 Saint Petersburg, Russia
- N.P. Bechtereva Institute of the Human Brain of the Russian Academy of Sciences, 197376 Saint Petersburg, Russia
| | | | - Veronika A. Prikhodko
- Department of Pharmacology and Clinical Pharmacology, Saint Petersburg State Chemical and Pharmaceutical University, 197022 Saint Petersburg, Russia
- N.P. Bechtereva Institute of the Human Brain of the Russian Academy of Sciences, 197376 Saint Petersburg, Russia
| | - Eduard Korkotian
- Department of Brain Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel
- Correspondence:
| | - Sergey V. Okovityi
- Department of Pharmacology and Clinical Pharmacology, Saint Petersburg State Chemical and Pharmaceutical University, 197022 Saint Petersburg, Russia
- N.P. Bechtereva Institute of the Human Brain of the Russian Academy of Sciences, 197376 Saint Petersburg, Russia
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4
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Tongta S, Daendee S, Kalandakanond-Thongsong S. Anxiety-like behavior and GABAergic system in ovariectomized rats exposed to chronic mild stress. Physiol Behav 2023; 258:114014. [PMID: 36328075 DOI: 10.1016/j.physbeh.2022.114014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/14/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022]
Abstract
Stress or low level of estrogen could promote anxiety and depression; thus, it is of interest to investigate the combined effect of mild stress and the lack of estrogen on mental disorders by utilizing an animal model. This study was conducted to assess anxiety- and depressive- like behaviors in ovariectomized (Ovx) rats exposed to chronic mild stress (CMS) and determine the alteration in gamma-aminobutyric acid (GABA)-related transmission. Ovx rats were randomly assigned into four groups: (1) estrogen replacement (E2-NoCMS), (2) estrogen replacement and exposure to CMS (E2-CMS), (3) vehicle (VEH-NoCMS), and (4) vehicle and exposure to CMS (VEH-CMS). Following 4-week CMS, VEH groups (VEH-NoCMS and VEH-CMS) showed a similar level of anxiety-like behavior in elevated T-maze, whereas E2-CMS, VEH-NoCMS and VEH-CMS showed anxiety-like behavior in open field. The depressive-like behavior in the force swimming test tended to be affected by estrogen deprivation than CMS. The alteration of the GABAergic system as determined from the GABA level and mRNA expression of GABA-related transmission (i.e., glutamic acid decarboxylase, GABA transporter and GABAA subunits) showed that the GABA level in the amygdala and frontal cortex was affected by CMS. For mRNA expression, the mRNA profile in the amygdala and hippocampus of VEH-NoCMS and E2-CMS was the same but different from those of VEH-NoCMS and E2-CMS. In addition, compared with E2-NoCMS, the mRNA profile in the frontal cortex was similar in VEH-NoCMS, E2-CMS, and VEH-CMS. These findings indicated that the underlying mechanism of the GABAergic system was differently modified, although VEH-NoCMS and VEH-CMS showed anxiety-like behavior. The findings of this study may provide a comprehensive understanding of the modulation of the GABAergic system during estrogen deprivation under CMS, as observed in menopausal women who were daily exposed to stress.
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Affiliation(s)
- Sushawadee Tongta
- Department of Veterinary Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Suwaporn Daendee
- College of Medicine and Public Health, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
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5
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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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6
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Graham BM. The impact of hormonal contraceptives on anxiety treatments: From preclinical models to clinical settings. Front Neuroendocrinol 2022; 67:101030. [PMID: 35995079 DOI: 10.1016/j.yfrne.2022.101030] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/10/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022]
Abstract
Exposure therapy is a central component of the first-line treatment for anxiety disorders, a common mental health condition that is twice as prevalent in women relative to men. A key underlying mechanism of exposure therapy is fear extinction, which is an active learning process supported by a neural circuitry that is highly regulated by ovarian hormones. This review synthesises research examining the impact of hormonal contraceptives on laboratory fear extinction tasks in female rats and women, and on exposure therapy in women with anxiety disorders. The evidence indicates that hormonal contraceptives have a detrimental impact on fear extinction and exposure therapy that is consistent across species, and from laboratory to clinical settings. Candidate pathways by which hormonal contraceptives impede fear extinction and exposure therapy include suppression of endogenous ovarian hormones and glucocorticoids, and downregulation of signalling pathways that support extinction learning. Key areas of focus for future research are discussed.
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Affiliation(s)
- Bronwyn M Graham
- School of Psychology, The University of New South Wales Australia, Sydney, New South Wales, Australia.
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Bernardo A, Lee P, Marcotte M, Mian MY, Rezvanian S, Sharmin D, Kovačević A, Savić MM, Cook JM, Sibille E, Prevot TD. Symptomatic and neurotrophic effects of GABAA receptor positive allosteric modulation in a mouse model of chronic stress. Neuropsychopharmacology 2022; 47:1608-1619. [PMID: 35701547 PMCID: PMC9283409 DOI: 10.1038/s41386-022-01360-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/17/2022] [Accepted: 05/31/2022] [Indexed: 12/27/2022]
Abstract
Chronic stress is a risk factor for Major Depressive Disorder (MDD), and in rodents, it recapitulates human behavioral, cellular and molecular changes. In MDD and after chronic stress, neuronal dysfunctions and deficits in GABAergic signaling are observed and responsible for symptom severity. GABA signals predominantly through GABAA receptors (GABAA-R) composed of various subunit types that relate to downstream outcomes. Activity at α2-GABAA-Rs contributes to anxiolytic properties, α5-GABAA-Rs to cognitive functions, and α1-GABAA-Rs to sedation. Therefore, a therapy aiming at increasing α2- and α5-GABAA-Rs activity, but devoid of α1-GABAA-R activity, has potential to address several symptomologies of depression while avoiding side-effects. This study investigated the activity profiles and behavioral efficacy of two enantiomers of each other (GL-II-73 and GL-I-54), separately and as a racemic mixture (GL-RM), and potential disease-modifying effects on neuronal morphology. Results confirm GL-I-54 and GL-II-73 exert positive allosteric modulation at the α2-, α3-, α5-GABAA-Rs and α5-containing GABAA-Rs, respectively, and separately reduces immobility in the forced swim test and improves stress-induced spatial working memory deficits. Using unpredictable chronic mild stress (UCMS), we show that acute and chronic administration of GL-RM provide pro-cognitive effects, with mild efficacy on mood symptoms, although at lower doses avoiding sedation. Morphology studies showed reversal of spine density loss caused by UCMS after chronic GL-RM treatment at apical and basal dendrites of the PFC and CA1. Together, these results support using a racemic mixture with combined α2-, α3-, α5-GABAA-R profile to reverse chronic stress-induced mood symptoms, cognitive deficits, and with anti-stress neurotrophic effects.
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Affiliation(s)
- Ashley Bernardo
- grid.155956.b0000 0000 8793 5925Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada
| | - Philip Lee
- grid.17063.330000 0001 2157 2938Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - Michael Marcotte
- grid.155956.b0000 0000 8793 5925Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada
| | - Md Yeunus Mian
- grid.267468.90000 0001 0695 7223Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, USA
| | - Sepideh Rezvanian
- grid.267468.90000 0001 0695 7223Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, USA
| | - Dishary Sharmin
- grid.267468.90000 0001 0695 7223Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, USA
| | - Aleksandra Kovačević
- grid.7149.b0000 0001 2166 9385Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Miroslav M. Savić
- grid.7149.b0000 0001 2166 9385Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - James M. Cook
- grid.267468.90000 0001 0695 7223Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, USA
| | - Etienne Sibille
- Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada. .,Department of Psychiatry, University of Toronto, Toronto, Canada.
| | - Thomas D. Prevot
- grid.155956.b0000 0000 8793 5925Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada ,grid.17063.330000 0001 2157 2938Department of Psychiatry, University of Toronto, Toronto, Canada
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8
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Rasmusson AM, Pineles SL, Brown KD, Pinna G. A role for deficits in GABAergic neurosteroids and their metabolites with NMDA receptor antagonist activity in the pathophysiology of posttraumatic stress disorder. J Neuroendocrinol 2022; 34:e13062. [PMID: 34962690 PMCID: PMC9233411 DOI: 10.1111/jne.13062] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/15/2021] [Accepted: 10/29/2021] [Indexed: 02/03/2023]
Abstract
Trauma-focused psychotherapies show general efficacy in post-traumatic stress disorder (PTSD), although outcomes vary substantially among individuals with PTSD and many patients do not achieve clinically meaningful symptom improvement. Several factors may contribute to poor treatment response, including genetic or environmental (e.g., stress) effects on neurobiological factors involved in learning and memory processes critical to PTSD recovery. In this review, we discuss the relationship between deficient GABAergic neurosteroid metabolites of progesterone, allopregnanolone (Allo) and pregnanolone (PA), and PTSD symptoms in men and women or PTSD-like behavioral abnormalities observed in male rodent models of PTSD. We also review the role and molecular underpinnings of learning and memory processes relevant to PTSD recovery, including extinction, extinction retention, reconsolidation of reactivated aversive memories and episodic non-aversive memory. We then discuss preclinical and clinical research that supports a role in these learning and memory processes for GABAergic neurosteroids and sulfated metabolites of Allo and PA that allosterically antagonize NMDA receptor function. Studies supporting the possible therapeutic impact of appropriately timed, acutely administered Allo or Allo analogs to facilitate extinction retention and/or block reconsolidation of aversive memories are also reviewed. Finally, we discuss important future directions for research in this area. Examining the varied and composite effects in PTSD of these metabolites of progesterone, as well as neuroactive derivatives of other parent steroids produced in the brain and the periphery, will likely enable a broadening of targets for treatment development. Defining contributions of these neuroactive steroids to common PTSD-comorbid psychiatric and medical conditions, as well as subpopulation-specific underlying dysfunctional physiological processes such as hypothalamic-pituitary-adrenal axis and immune system dysregulation, may also enable development of more effective multisystem precision medicines to prevent and treat the broader, polymorbid sequelae of extreme and chronic stress.
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Affiliation(s)
- Ann M. Rasmusson
- VA National Center for PTSD, Women’s Health Science Division, Department of Veterans Affairs, Boston, MA 02130, U.S.A
- Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118
| | - Suzanne L. Pineles
- VA National Center for PTSD, Women’s Health Science Division, Department of Veterans Affairs, Boston, MA 02130, U.S.A
- Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118
| | - Kayla D. Brown
- Behavioral Neurosciences PhD Program, Boston University Medical Campus, Boston, MA, 02118, U.S.A
| | - Graziano Pinna
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, 60612, U.S.A
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9
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Baldi E, Costa A, Rani B, Passani MB, Blandina P, Romano A, Provensi G. Oxytocin and Fear Memory Extinction: Possible Implications for the Therapy of Fear Disorders? Int J Mol Sci 2021; 22:10000. [PMID: 34576161 PMCID: PMC8467761 DOI: 10.3390/ijms221810000] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/07/2021] [Accepted: 09/10/2021] [Indexed: 02/07/2023] Open
Abstract
Several psychiatric conditions such as phobias, generalized anxiety, and post-traumatic stress disorder (PTSD) are characterized by pathological fear and anxiety. The main therapeutic approach used in the management of these disorders is exposure-based therapy, which is conceptually based upon fear extinction with the formation of a new safe memory association, allowing the reduction in behavioral conditioned fear responses. Nevertheless, this approach is only partially resolutive, since many patients have difficulty following the demanding and long process, and relapses are frequently observed over time. One strategy to improve the efficacy of the cognitive therapy is the combination with pharmacological agents. Therefore, the identification of compounds able to strengthen the formation and persistence of the inhibitory associations is a key goal. Recently, growing interest has been aroused by the neuropeptide oxytocin (OXT), which has been shown to have anxiolytic effects. Furthermore, OXT receptors and binding sites have been found in the critical brain structures involved in fear extinction. In this review, the recent literature addressing the complex effects of OXT on fear extinction at preclinical and clinical levels is discussed. These studies suggest that the OXT roles in fear behavior are due to its local effects in several brain regions, most notably, distinct amygdaloid regions.
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Affiliation(s)
- Elisabetta Baldi
- Section of Physiological Sciences, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy;
| | - Alessia Costa
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences (DSS), University of Florence, 50139 Florence, Italy; (A.C.); (B.R.); (M.B.P.)
| | - Barbara Rani
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences (DSS), University of Florence, 50139 Florence, Italy; (A.C.); (B.R.); (M.B.P.)
| | - Maria Beatrice Passani
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences (DSS), University of Florence, 50139 Florence, Italy; (A.C.); (B.R.); (M.B.P.)
| | - Patrizio Blandina
- Section of Pharmacology of Toxicology, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, 50139 Florence, Italy;
| | - Adele Romano
- Department of Physiology and Pharmacology ‘V. Erspamer’, Sapienza University of Rome, 00185 Rome, Italy;
| | - Gustavo Provensi
- Section of Pharmacology of Toxicology, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, 50139 Florence, Italy;
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10
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Cummings KA, Lacagnina AF, Clem RL. GABAergic microcircuitry of fear memory encoding. Neurobiol Learn Mem 2021; 184:107504. [PMID: 34425220 DOI: 10.1016/j.nlm.2021.107504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 12/30/2022]
Abstract
The paradigm of fear conditioning is largely responsible for our current understanding of how memories are encoded at the cellular level. Its most fundamental underlying mechanism is considered to be plasticity of synaptic connections between excitatory projection neurons (PNs). However, recent studies suggest that while PNs execute critical memory functions, their activity at key stages of learning and recall is extensively orchestrated by a diverse array of GABAergic interneurons (INs). Here we review the contributions of genetically-defined INs to processing of threat-related stimuli in fear conditioning, with a particular focus on how synaptic interactions within interconnected networks of INs modulates PN activity through both inhibition and disinhibition. Furthermore, we discuss accumulating evidence that GABAergic microcircuits are an important locus for synaptic plasticity during fear learning and therefore a viable substrate for long-term memory. These findings suggest that further investigation of INs could unlock unique conceptual insights into the organization and function of fear memory networks.
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Affiliation(s)
- Kirstie A Cummings
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Neurobiology, University of Alabama Birmingham School of Medicine, Birmingham, AL 35294, United States
| | - Anthony F Lacagnina
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Roger L Clem
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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11
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Lewis V, Laberge F, Heyland A. Transcriptomic signature of extinction learning in the brain of the fire-bellied toad, Bombina orientalis. Neurobiol Learn Mem 2021; 184:107502. [PMID: 34391934 DOI: 10.1016/j.nlm.2021.107502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/21/2021] [Accepted: 08/08/2021] [Indexed: 11/26/2022]
Abstract
Insight into the molecular and cellular mechanisms of learning and memory from a diverse array of taxa contributes to our understanding of the evolution of these processes. The fire-bellied toad, Bombina orientalis, is a basal anuran amphibian model species who could help us describe shared and divergent characteristics of learning and memory mechanisms between amphibians and other vertebrates, and hence answer questions about the evolution of learning. Utilizing next generation sequencing techniques, we profiled gene expression patterns associated with the extinction of prey-catching conditioning in the brain of the fire-bellied toad. For this purpose, gene expression was at first compared between toads sacrificed after acquisition and extinction of the conditioned response. A second comparison was done between toads submitted to extinction following either short or long acquisition training, which results in toads displaying response extinction or resistance to extinction, respectively. We analyzed brain tissue transcription profiles common to both acquisition and extinction learning, or unique to extinction learning and resistance to extinction, and found significant overlap in gene expression related to molecular pathways involving neuronal plasticity (e.g. structural modification, transcription). However, extinction learning induced a unique GABAergic transcriptomic signal, which may be responsible for suppression of the original response memory. Further, when comparing extinction learning in short- and long-trained groups, short training engaged many pathways related to neuronal plasticity, as expected, but long training engaged molecular pathways related to the suppression of learning through epigenetic mediated transcriptional suppression and inhibitory neurotransmission. Overall, gene expression patterns associated with extinction learning in the fire-bellied toad were similar to those found in mammals submitted to extinction, although some divergent profiles highlighted potential differences in the mechanisms of learning and memory among tetrapods.
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Affiliation(s)
- Vern Lewis
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Frédéric Laberge
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Andreas Heyland
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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12
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Adkins JM, Lynch J, Gray M, Jasnow AM. Presynaptic GABA B receptor inhibition sex dependently enhances fear extinction and attenuates fear renewal. Psychopharmacology (Berl) 2021; 238:2059-2071. [PMID: 33855580 PMCID: PMC8295214 DOI: 10.1007/s00213-021-05831-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/22/2021] [Indexed: 12/11/2022]
Abstract
Anxiety and trauma-related disorders are highly prevalent worldwide, and are associated with altered associative fear learning. Despite the effectiveness of exposure therapy, which aims to reduce associative fear responses, relapse rates remain high. This is due, in part, to the context specificity of exposure therapy, which is a form of extinction. Many studies show that fear relapses when mice are tested outside the extinction context, and this is known as fear renewal. Using Pavlovian fear conditioning and extinction, we can study the mechanisms underlying extinction and renewal. The aim of the current experiment was to identify the role of presynaptic GABAB receptors in these two processes. Previous work from our lab showed that genetic deletion or pharmacological inhibition of GABAB(1a) receptors that provide presynaptic inhibition on glutamatergic terminals reduces context specificity and leads to generalization. We therefore hypothesized that inactivation of these presynaptic GABAB receptors could be used to reduce the context specificity associated with fear extinction training and suppress renewal when mice are tested outside of the extinction context. Using CGP 36216, an antagonist specific for presynaptic GABAB receptors, we blocked presynaptic GABAB receptors using intracerebroventricular injections during various time points of extinction learning in male and female mice. Results showed that blocking these receptors pre- and post-extinction training led to enhanced extinction learning in male mice only. We also found that post-extinction infusions of CGP reduced renewal rates in male mice when they were tested outside of the extinction context. In an attempt to localize the function of presynaptic GABAB receptors within regions of the extinction circuit, we infused CGP locally within the basolateral amygdala or dorsal hippocampus. We failed to reduce renewal when CGP was infused directly within these regions, suggesting that presynaptic inhibition within these regions per se may not be necessary for driving context specificity during extinction learning. Together, these results show an important sex-dependent role of presynaptic GABAB receptors in extinction and renewal processes and identify a novel receptor target that may be used to design pharmacotherapies to enhance the effectiveness of exposure therapy.
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Affiliation(s)
- Jordan M Adkins
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Joseph Lynch
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Michael Gray
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Aaron M Jasnow
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA.
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA.
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC, 29209, USA.
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13
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Reducing glutamic acid decarboxylase in the dorsal dentate gyrus attenuates juvenile stress induced emotional and cognitive deficits. Neurobiol Stress 2021; 15:100350. [PMID: 34150959 PMCID: PMC8193143 DOI: 10.1016/j.ynstr.2021.100350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/11/2021] [Accepted: 05/28/2021] [Indexed: 11/22/2022] Open
Abstract
A high degree of regional, temporal and molecular specificity is evident in the regulation of GABAergic signaling in stress-responsive circuitry, hampering the use of systemic GABAergic modulators for the treatment of stress-related psychopathology. Here we investigated the effectiveness of local intervention with the GABA synthetic enzymes GAD65 and GAD67 in the dorsal dentate gyrus (dDG) vs ventral DG (vDG) to alleviate anxiety-like behavior and stress-induced symptoms in the rat. We induced shRNA-mediated knock down of either GAD65 or GAD67 with lentiviral vectors microinjected into the dDG or vDG of young adult male rats and examined anxiety behavior, learning and memory performance. Subsequently we tested whether reducing GAD65 expression in the dDG would also confer resilience against juvenile stress-induced behavioral and physiological symptoms in adulthood. While knock down of either isoform in the vDG increased anxiety levels in the open field and the elevated plus maze tests, the knock down of GAD65, but not GAD67, in the dDG conferred a significant reduction in anxiety levels. Strikingly, this manipulation also attenuated juvenile stress evoked anxiety behavior, cognitive and synaptic plasticity impairments. Local GABAergic circuitry in the DG plays an important and highly region-specific role in control of emotional behavior and stress responding. Reduction of GAD65 expression in the dDG appears to provide resilience to juvenile stress-induced emotional and cognitive deficits, opening a new direction towards addressing a significant risk factor for developing stress and trauma-related psychopathologies later in life. GAD67/65 in the dorsal/ventral dentate gyrus differentially modulate anxiety. Reduced GAD65 expression in the dorsal dentate gyrus supports stress resilience. The dorsal dentate gyrus plays a key role in stress resilience.
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14
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Salinas-Hernández XI, Duvarci S. Dopamine in Fear Extinction. Front Synaptic Neurosci 2021; 13:635879. [PMID: 33732133 PMCID: PMC7956961 DOI: 10.3389/fnsyn.2021.635879] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/09/2021] [Indexed: 11/30/2022] Open
Abstract
The ability to extinguish fear memories when threats are no longer present is critical for adaptive behavior. Fear extinction represents a new learning process that eventually leads to the formation of extinction memories. Understanding the neural basis of fear extinction has considerable clinical significance as deficits in extinction learning are the hallmark of human anxiety disorders. In recent years, the dopamine (DA) system has emerged as one of the key regulators of fear extinction. In this review article, we highlight recent advances that have demonstrated the crucial role DA plays in mediating different phases of fear extinction. Emerging concepts and outstanding questions for future research are also discussed.
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Affiliation(s)
| | - Sevil Duvarci
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
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15
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Skórzewska A, Lehner M, Wisłowska-Stanek A, Turzyńska D, Sobolewska A, Krząścik P, Szyndler J, Maciejak P, Chmielewska N, Kołosowska K, Płaźnik A. Individual susceptibility or resistance to posttraumatic stress disorder-like behaviours. Behav Brain Res 2020; 386:112591. [PMID: 32194190 DOI: 10.1016/j.bbr.2020.112591] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 12/20/2022]
Abstract
The aim of this study was to explore the neurobiological background of individual susceptibility and resistance to the development of posttraumatic stress disorder (PTSD)-like behaviours. Rats were divided into susceptible, PTSD(+), and resistant, PTSD(-), groups based on freezing duration during exposure to aversive context and the time spent in the central area in open field test one week after threefold stress experience (modified single prolonged stress). PTSD(-) rats showed increased concentrations of corticosterone in plasma and changes in GAD67 expression: decreased in the infralimbic cortex (IL) and increased in the lateral amygdala (LA), dentate gyrus (DG), and CA1 area of the hippocampus. Moreover, in this group, we found an increase in the number of CRF-positive nuclei in the parvocellular neurons of the paraventricular hypothalamic nucleus (pPVN). The PTSD(+) group, compared to PTSD(-) rats, had decreased concentrations of corticosterone in plasma and reduced CRF expression in the pPVN, higher CRF expression in the CA1, increased expression of CRF-positive nuclei and GR receptors in the CA3 area of the hippocampus, and increased expression of GR receptors in the DG and the central amygdala (CeA). Biochemical analysis showed higher concentrations of noradrenaline, glutamic acid in the dorsal hippocampus and amygdala and lower levels of dopamine and its metabolites in the amygdala of the PTSD(+) group than in the PTSD(-) group. The study revealed different behavioural and biochemical profiles of PTSD(+) and PTSD(-) rats and suggested that individual differences in hypothalamic-pituitary-adrenal (HPA) axis activity may determine hippocampal- and amygdala-dependent memory and fear processing.
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Affiliation(s)
- Anna Skórzewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland.
| | - Małgorzata Lehner
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
| | - Aleksandra Wisłowska-Stanek
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, 1B Banacha Street, 02-097, Warsaw, Poland
| | - Danuta Turzyńska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
| | - Alicja Sobolewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
| | - Paweł Krząścik
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, 1B Banacha Street, 02-097, Warsaw, Poland
| | - Janusz Szyndler
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, 1B Banacha Street, 02-097, Warsaw, Poland
| | - Piotr Maciejak
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland; Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, 1B Banacha Street, 02-097, Warsaw, Poland
| | - Natalia Chmielewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
| | - Karolina Kołosowska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
| | - Adam Płaźnik
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957, Warsaw, Poland
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16
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Maddox SA, Hartmann J, Ross RA, Ressler KJ. Deconstructing the Gestalt: Mechanisms of Fear, Threat, and Trauma Memory Encoding. Neuron 2019; 102:60-74. [PMID: 30946827 DOI: 10.1016/j.neuron.2019.03.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/03/2019] [Accepted: 03/12/2019] [Indexed: 01/14/2023]
Abstract
Threat processing is central to understanding debilitating fear- and trauma-related disorders such as posttraumatic stress disorder (PTSD). Progress has been made in understanding the neural circuits underlying the "engram" of threat or fear memory formation that complements a decades-old appreciation of the neurobiology of fear and threat involving hub structures such as the amygdala. In this review, we examine key recent findings, as well as integrate the importance of hormonal and physiological approaches, to provide a broader perspective of how bodily systems engaged in threat responses may interact with amygdala-based circuits in the encoding and updating of threat-related memory. Understanding how trauma-related memories are encoded and updated throughout the brain and the body will ultimately lead to novel biologically-driven approaches for treatment and prevention.
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Affiliation(s)
- Stephanie A Maddox
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jakob Hartmann
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Rachel A Ross
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Kerry J Ressler
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA.
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17
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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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18
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Zhang Y, Ouyang K, Lipina TV, Wang H, Zhou Q. Conditioned stimulus presentations alter anxiety level in fear-conditioned mice. Mol Brain 2019; 12:28. [PMID: 30925893 PMCID: PMC6441152 DOI: 10.1186/s13041-019-0445-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/13/2019] [Indexed: 11/26/2022] Open
Abstract
It is generally believed that fear is rapidly triggered by a distinct cue while anxiety onset is less precise and not associated with a distinct cue. Although it has been claimed that both processes can be measured with certain independence of each other, it is unclear how exactly they differ. In this study, we measured anxiety in mice that received discriminative fear conditioning using behavioral, heart rate and calcium (Ca2+) responses in the ventral hippocampal CA1 (vCA1) neurons. We found that the occurrence of fear significantly interfered with anxiety measurements under various conditions. Diazepam reduced basal anxiety level but had no effect during the presentation of conditioned stimulus (CS). Injection of an inhibitory peptide of PKMzeta (ZIP) into the basolateral amygdala almost entirely abolished CS-triggered fear expression and reduced anxiety to basal level. Heart rate measures suggested a small reduction in anxiety during CS-. Calcium responses in the lateral hypothalamus-projecting vCA1 neurons showed a steady decay during CS suggesting a reduced anxiety. Thus, under our experimental conditions, CS presentations likely reduce anxiety level in the fear-conditioned mice.
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Affiliation(s)
- Yujie Zhang
- State key laboratory of chemical oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Kunfu Ouyang
- State key laboratory of chemical oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Tatiana V Lipina
- Federal State Budgetary Scientific Institution, Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,University of Toronto, Department of Pharmacology & Toxicology, Toronto, Ontario, Canada
| | - Hong Wang
- State key laboratory of chemical oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Qiang Zhou
- State key laboratory of chemical oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China.
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19
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Li K, Chen HS, Li D, Li HH, Wang J, Jia L, Wu PF, Long LH, Hu ZL, Chen JG, Wang F. SAR405, a Highly Specific VPS34 Inhibitor, Disrupts Auditory Fear Memory Consolidation of Mice via Facilitation of Inhibitory Neurotransmission in Basolateral Amygdala. Biol Psychiatry 2019; 85:214-225. [PMID: 30253884 DOI: 10.1016/j.biopsych.2018.07.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/18/2018] [Accepted: 07/29/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Autophagy has been demonstrated to play an important role in memory deficits as well as the degradation of neurotransmitter receptors. SAR405 is a newly discovered inhibitor that can specifically inhibit vacuolar sorting protein 34 and prevent autophagosome biogenesis. However, the effects of SAR405 on memory processes remain largely unknown. METHODS Western blotting, immunofluorescence, and transmission electron microscopy were used to assess the level of autophagy after fear conditioning and SAR405 treatment. Behavioral tests, biotinylation assay, electrophysiology, and co-immunoprecipitation were used to unravel the mechanisms of SAR405 in memory consolidation. RESULTS SAR405 infusion into the basolateral amygdala impaired long-term memory through autophagy inhibition. Furthermore, the trafficking of gamma-aminobutyric acid type A receptors (GABAARs) following fear conditioning was disrupted by SAR405, and the decreased frequency and amplitude of miniature inhibitory postsynaptic currents induced by fear conditioning were also reversed by SAR405, suggesting that SAR405 disrupted memory consolidation through blockade of the downregulated inhibitory neurotransmission in basolateral amygdala. GABAAR-associated protein (GABARAP) and its interaction with GABAAR γ2 subunit were found to be upregulated after fear conditioning, and SAR405 could suppress this increased interaction. Moreover, disruption of the GABARAP-GABAAR binding by a trans-activating transcriptional activator-GABARAP inhibitory peptide blocked the decrease in surface expression of GABAARs and attenuated long-term memory. CONCLUSIONS The present study suggests that SAR405 can prevent the memory consolidation via intervening autophagy and GABAAR trafficking and has a potential therapeutic value for disorders characterized by exaggerated fear memories, such as posttraumatic stress disorder.
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Affiliation(s)
- Kuan Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Sheng Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Di Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hou-Hong Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ji Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Jia
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng-Fei Wu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, the Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China
| | - Li-Hong Long
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, the Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Ministry of Education of China, Wuhan, China; Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China
| | - Zhuang-Li Hu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, the Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, the Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Ministry of Education of China, Wuhan, China; Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China; Collaborative Innovation Center for Brain Science, Wuhan, China.
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Laboratory of Neuropsychiatric Diseases, the Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China; Key Laboratory of Neurological Diseases, Ministry of Education of China, Wuhan, China; Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China; Collaborative Innovation Center for Brain Science, Wuhan, China.
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20
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Abstract
Learned safety is a fear inhibitory mechanism, which regulates fear responses, promotes episodes of safety and generates positive affective states. Despite its potential as experimental model for several psychiatric illnesses, including post-traumatic stress disorder and depression, the molecular mechanisms of learned safety remain poorly understood, We here investigated the molecular mediators of learned safety, focusing on the characterization of miRNA expression in the basolateral amygdala (BLA). Comparing levels of 22 miRNAs in learned safety and learned fear trained mice, six safety-related miRNAs, including three members of the miR-132/-212 family, were identified. A gain-of-function approach based upon in-vivo transfection of a specific miRNA mimic, and miR-132/212 knock-out mice as loss-of-function tool were used in order to determine the relevance of miR-132 for learned safety at the behavioral and the neuronal functional levels. Using a designated bioinformatic approach, PTEN and GAT1 were identified as potential novel miR-132 target genes and further experimentally validated. We here firstly provide evidence for a regulation of amygdala miRNA expression in learned safety and propose miR-132 as signature molecule to be considered in future preclinical and translational approaches testing the transdiagnostic relevance of learned safety as intermediate phenotype in fear and stress-related disorders.
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21
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Liu YM, Fan HR, Deng S, Zhu T, Yan Y, Ge WH, Li WG, Li F. Methyleugenol Potentiates Central Amygdala GABAergic Inhibition and Reduces Anxiety. J Pharmacol Exp Ther 2018; 368:1-10. [DOI: 10.1124/jpet.118.250779] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022] Open
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22
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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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23
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An Emerging Circuit Pharmacology of GABA A Receptors. Trends Pharmacol Sci 2018; 39:710-732. [PMID: 29903580 DOI: 10.1016/j.tips.2018.04.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/23/2018] [Accepted: 04/17/2018] [Indexed: 12/21/2022]
Abstract
In the past 20 years we have learned a great deal about GABAA receptor (GABAAR) subtypes, and which behaviors are regulated or which drug effects are mediated by each subtype. However, the question of where GABAARs involved in specific drug effects and behaviors are located in the brain remains largely unanswered. We review here recent studies taking a circuit pharmacology approach to investigate the functions of GABAAR subtypes in specific brain circuits controlling fear, anxiety, learning, memory, reward, addiction, and stress-related behaviors. The findings of these studies highlight the complexity of brain inhibitory systems and the importance of taking a subtype-, circuit-, and neuronal population-specific approach to develop future therapeutic strategies using cell type-specific drug delivery.
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24
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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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25
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Temme SJ, Murphy GG. The L-type voltage-gated calcium channel Ca V1.2 mediates fear extinction and modulates synaptic tone in the lateral amygdala. ACTA ACUST UNITED AC 2017; 24:580-588. [PMID: 29038219 PMCID: PMC5647931 DOI: 10.1101/lm.045773.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/17/2017] [Indexed: 12/15/2022]
Abstract
L-type voltage-gated calcium channels (LVGCCs) have been implicated in both the formation and the reduction of fear through Pavlovian fear conditioning and extinction. Despite the implication of LVGCCs in fear learning and extinction, studies of the individual LVGCC subtypes, CaV1.2 and CaV1.3, using transgenic mice have failed to find a role of either subtype in fear extinction. This discontinuity between the pharmacological studies of LVGCCs and the studies investigating individual subtype contributions could be due to the limited neuronal deletion pattern of the CaV1.2 conditional knockout mice previously studied to excitatory neurons in the forebrain. To investigate the effects of deletion of CaV1.2 in all neuronal populations, we generated CaV1.2 conditional knockout mice using the synapsin1 promoter to drive Cre recombinase expression. Pan-neuronal deletion of CaV1.2 did not alter basal anxiety or fear learning. However, pan-neuronal deletion of CaV1.2 resulted in a significant deficit in extinction of contextual fear, implicating LVGCCs, specifically CaV1.2, in extinction learning. Further exploration on the effects of deletion of CaV1.2 on inhibitory and excitatory input onto the principle neurons of the lateral amygdala revealed a significant shift in inhibitory/excitatory balance. Together these data illustrate an important role of CaV1.2 in fear extinction and the synaptic regulation of activity within the amygdala.
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Affiliation(s)
- Stephanie J Temme
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109-2200, USA
| | - Geoffrey G Murphy
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109-2200, USA.,Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109-2200, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200, USA
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26
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Müller Herde A, Benke D, Ralvenius WT, Mu L, Schibli R, Zeilhofer HU, Krämer SD. GABAA receptor subtypes in the mouse brain: Regional mapping and diazepam receptor occupancy by in vivo [18F]flumazenil PET. Neuroimage 2017; 150:279-291. [DOI: 10.1016/j.neuroimage.2017.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/22/2017] [Accepted: 02/09/2017] [Indexed: 12/19/2022] Open
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27
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Calakos KC, Blackman D, Schulz AM, Bauer EP. Distribution of type I corticotropin-releasing factor (CRF1) receptors on GABAergic neurons within the basolateral amygdala. Synapse 2017; 71:10.1002/syn.21953. [PMID: 27997737 PMCID: PMC7876706 DOI: 10.1002/syn.21953] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 12/23/2022]
Abstract
The neuropeptide corticotropin-releasing factor (CRF) plays a critical role in mediating anxiety-like responses to stressors, and dysfunction of the CRF system has been linked to the etiology of several psychiatric disorders. Extra-hypothalamic CRF can also modulate learning and memory formation, including amygdala-dependent learning. The basolateral nucleus of the amygdala (BLA) contains dense concentrations of CRF receptors, yet the distribution of these receptors on specific neuronal subtypes within the BLA has not been characterized. Here, we quantified the expression of CRF receptors on three nonoverlapping classes of GABAergic interneurons: those containing the calcium-binding protein parvalbumin (PV), and those expressing the neuropeptides somatostatin (SOM) or cholecystokinin (CCK). While the majority of PV+ neurons and roughly half of CCK+ neurons expressed CRF receptors, they were expressed to a much lesser extent on SOM+ interneurons. Knowledge of the distribution of CRF receptors within the BLA can provide insight into how manipulations of the CRF system modulate fear and anxiety-like behaviors.
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Affiliation(s)
- Katina C Calakos
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Dakota Blackman
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Alexandra M Schulz
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Elizabeth P Bauer
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
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28
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Saha R, Knapp S, Chakraborty D, Horovitz O, Albrecht A, Kriebel M, Kaphzan H, Ehrlich I, Volkmer H, Richter-Levin G. GABAergic Synapses at the Axon Initial Segment of Basolateral Amygdala Projection Neurons Modulate Fear Extinction. Neuropsychopharmacology 2017; 42:473-484. [PMID: 27634356 PMCID: PMC5399240 DOI: 10.1038/npp.2016.205] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 11/09/2022]
Abstract
Inhibitory synaptic transmission in the amygdala has a pivotal role in fear learning and its extinction. However, the local circuits formed by GABAergic inhibitory interneurons within the amygdala and their detailed function in shaping these behaviors are not well understood. Here we used lentiviral-mediated knockdown of the cell adhesion molecule neurofascin in the basolateral amygdala (BLA) to specifically remove inhibitory synapses at the axon initial segment (AIS) of BLA projection neurons. Quantitative analysis of GABAergic synapse markers and measurement of miniature inhibitory postsynaptic currents in BLA projection neurons after neurofascin knockdown ex vivo confirmed the loss of GABAergic input. We then studied the impact of this manipulation on anxiety-like behavior and auditory cued fear conditioning and its extinction as BLA related behavioral paradigms, as well as on long-term potentiation (LTP) in the ventral subiculum-BLA pathway in vivo. BLA knockdown of neurofascin impaired ventral subiculum-BLA-LTP. While this manipulation did not affect anxiety-like behavior and fear memory acquisition and consolidation, it specifically impaired extinction. Our findings indicate that modification of inhibitory synapses at the AIS of BLA projection neurons is sufficient to selectively impair extinction behavior. A better understanding of the role of distinct GABAergic synapses may provide novel and more specific targets for therapeutic interventions in extinction-based therapies.
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Affiliation(s)
- Rinki Saha
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Stephanie Knapp
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany,Graduate School for Neural and Behavioral Science, University of Tübingen, Tübingen, Germany
| | | | - Omer Horovitz
- Department of Psychology, 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
| | - Martin Kriebel
- NMI Natural and Medical Sciences Institute, University of Tübingen, Reutlingen, Germany
| | - Hanoch Kaphzan
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Hansjürgen Volkmer
- NMI Natural and Medical Sciences Institute, University of Tübingen, Reutlingen, Germany
| | - Gal Richter-Levin
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel,Department of Psychology, University of Haifa, Haifa, Israel,The Institute for the Study of Affective Neuroscience, University of Haifa, Haifa, Israel,Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Avenue 199, Haifa 31905, Israel, Tel: +972 48240962, Fax: +972 48288578, E-mail:
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29
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Yang WZ, Liu TT, Cao JW, Chen XF, Liu X, Wang M, Su X, Zhang SQ, Qiu BL, Hu WX, Liu LY, Ma L, Yu YC. Fear Erasure Facilitated by Immature Inhibitory Neuron Transplantation. Neuron 2016; 92:1352-1367. [DOI: 10.1016/j.neuron.2016.11.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 04/14/2016] [Accepted: 11/02/2016] [Indexed: 02/04/2023]
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30
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Effects of Blockade of D1 and D2 Receptors in the Basolateral Amygdala on the Behavior of Rats with High and Low Levels of Anxiety and Fear. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s11055-016-0352-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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31
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Erasure of fear memories is prevented by Nogo Receptor 1 in adulthood. Mol Psychiatry 2016; 21:1281-9. [PMID: 26619810 PMCID: PMC4887429 DOI: 10.1038/mp.2015.179] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/06/2015] [Accepted: 10/14/2015] [Indexed: 11/12/2022]
Abstract
Critical periods are temporary windows of heightened neural plasticity early in development. For example, fear memories in juvenile rodents are subject to erasure following extinction training, while after closure of this critical period, extinction training only temporarily and weakly suppresses fear memories. Persistence of fear memories is important for survival, but the inability to effectively adapt to the trauma is a characteristic of post-traumatic stress disorder (PTSD). We examined whether Nogo Receptor 1 (NgR1) regulates the plasticity associated with fear extinction. The loss of NgR1 function in adulthood eliminates spontaneous fear recovery and fear renewal, with a restoration of fear reacquisition rate equal to that of naive mice; thus, mimicking the phenotype observed in juvenile rodents. Regional gene disruption demonstrates that NgR1 expression is required in both the basolateral amygdala (BLA) and infralimbic (IL) cortex to prevent fear erasure. NgR1 expression by parvalbumin expressing interneurons is essential for limiting extinction-dependent plasticity. NgR1 gene deletion enhances anatomical changes of inhibitory synapse markers after extinction training. Thus, NgR1 robustly inhibits elimination of fear expression in the adult brain and could serve as a therapeutic target for anxiety disorders, such as PTSD.
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32
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Lucas EK, Jegarl AM, Morishita H, Clem RL. Multimodal and Site-Specific Plasticity of Amygdala Parvalbumin Interneurons after Fear Learning. Neuron 2016; 91:629-43. [PMID: 27427462 DOI: 10.1016/j.neuron.2016.06.032] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 05/12/2016] [Accepted: 06/15/2016] [Indexed: 01/02/2023]
Abstract
Stimulus processing in fear conditioning is constrained by parvalbumin interneurons (PV-INs) through inhibition of principal excitatory neurons. However, the contributions of PV-IN microcircuits to input gating and long-term plasticity in the fear system remain unknown. Here we interrogate synaptic connections between afferent pathways, PV-INs, and principal excitatory neurons in the basolateral amygdala. We find that subnuclei of this region are populated two functionally distinct PV-IN networks. PV-INs in the lateral (LA), but not the basal (BA), amygdala possess complex dendritic arborizations, receive potent excitatory drive, and mediate feedforward inhibition onto principal neurons. After fear conditioning, PV-INs exhibit nucleus- and target-selective plasticity, resulting in persistent reduction of their excitatory input and inhibitory output in LA but not BA. These data reveal previously overlooked specializations of amygdala PV-INs and indicate specific circuit mechanisms for inhibitory plasticity during the encoding of associative fear memories.
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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, New York, NY 10029, USA
| | - Anita M Jegarl
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hirofumi Morishita
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Psychiatry and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Roger L Clem
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Psychiatry and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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33
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34
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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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35
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Skórzewska A, Lehner M, Wisłowska-Stanek A, Turzyńska D, Sobolewska A, Krząścik P, Płaźnik A. GABAergic control of the activity of the central nucleus of the amygdala in low- and high-anxiety rats. Neuropharmacology 2015; 99:566-76. [DOI: 10.1016/j.neuropharm.2015.08.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 12/20/2022]
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36
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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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37
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Letzkus J, Wolff S, Lüthi A. Disinhibition, a Circuit Mechanism for Associative Learning and Memory. Neuron 2015; 88:264-76. [PMID: 26494276 DOI: 10.1016/j.neuron.2015.09.024] [Citation(s) in RCA: 240] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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38
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Botta P, Demmou L, Kasugai Y, Markovic M, Xu C, Fadok JP, Lu T, Poe MM, Xu L, Cook JM, Rudolph U, Sah P, Ferraguti F, Lüthi A. Regulating anxiety with extrasynaptic inhibition. Nat Neurosci 2015; 18:1493-500. [PMID: 26322928 PMCID: PMC4607767 DOI: 10.1038/nn.4102] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/06/2015] [Indexed: 12/30/2022]
Abstract
Aversive experiences can lead to complex behavioral adaptations including increased levels of anxiety and fear generalization. The neuronal mechanisms underlying such maladaptive behavioral changes, however, are poorly understood. Here, using a combination of behavioral, physiological and optogenetic approaches in mouse, we identify a specific subpopulation of central amygdala neurons expressing protein kinase C δ (PKCδ) as key elements of the neuronal circuitry controlling anxiety. Moreover, we show that aversive experiences induce anxiety and fear generalization by regulating the activity of PKCδ(+) neurons via extrasynaptic inhibition mediated by α5 subunit-containing GABAA receptors. Our findings reveal that the neuronal circuits that mediate fear and anxiety overlap at the level of defined subpopulations of central amygdala neurons and demonstrate that persistent changes in the excitability of a single cell type can orchestrate complex behavioral changes.
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Affiliation(s)
- Paolo Botta
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Lynda Demmou
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Yu Kasugai
- Department of Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Milica Markovic
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Chun Xu
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jonathan P Fadok
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Tingjia Lu
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Michael M Poe
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Li Xu
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland, Australia
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital and Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts, USA
| | - Pankaj Sah
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland, Australia
| | - Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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39
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Bosch D, Ehrlich I. Postnatal maturation of GABAergic modulation of sensory inputs onto lateral amygdala principal neurons. J Physiol 2015; 593:4387-409. [PMID: 26227545 DOI: 10.1113/jp270645] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/28/2015] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Throughout life, fear learning is indispensable for survival and neural plasticity in the lateral amygdala underlies this learning and storage of fear memories. During development, properties of fear learning continue to change into adulthood, but currently little is known about changes in amygdala circuits that enable these behavioural transitions. In recordings from neurons in lateral amygdala brain slices from infant up to adult mice, we show that spontaneous and evoked excitatory and inhibitory synaptic transmissions mature into adolescence. At this time, increased inhibitory activity and signalling has the ability to restrict the function of excitation by presynaptic modulation, and may thus enable precise stimulus associations to limit fear generalization from adolescence onward. Our results provide a basis for addressing plasticity mechanisms that underlie altered fear behaviour in young animals. ABSTRACT Convergent evidence suggests that plasticity in the lateral amygdala (LA) participates in acquisition and storage of fear memory. Sensory inputs from thalamic and cortical areas activate principal neurons and local GABAergic interneurons, which provide feed-forward inhibition that tightly controls LA activity and plasticity via pre- and postsynaptic GABAA and GABAB receptors. GABAergic control is also critical during fear expression, generalization and extinction in adult animals. During rodent development, properties of fear and extinction learning continue to change into early adulthood. Currently, few studies have assessed physiological changes in amygdala circuits that may enable these behavioural transitions. To obtain first insights, we investigated changes in spontaneous and sensory input-evoked inhibition onto LA principal neurons and then focused on GABAB receptor-mediated modulation of excitatory sensory inputs in infant, juvenile, adolescent and young adult mice. We found that spontaneous and sensory-evoked inhibition increased during development. Physiological changes were accompanied by changes in dendritic morphology. While GABAB heteroreceptors were functionally expressed on sensory afferents already early in development, they could only be physiologically recruited by sensory-evoked GABA release to mediate heterosynaptic inhibition from adolescence onward. Furthermore, we found GABAB -mediated tonic inhibition of sensory inputs by ambient GABA that also emerged in adolescence. The observed increase in GABAergic drive may be a substrate for providing modulatory GABA. Our data suggest that GABAB -mediated tonic and evoked presynaptic inhibition can suppress sensory input-driven excitation in the LA to enable precise stimulus associations and limit generalization of conditioned fear from adolescence onward.
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Affiliation(s)
- Daniel Bosch
- Hertie Institute for Clinical Brain Research, University of Tuebingen, Otfried-Mueller-Str. 25, 72076, Tuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Otfried-Mueller-Str. 25, 72076, Tuebingen, Germany
| | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain Research, University of Tuebingen, Otfried-Mueller-Str. 25, 72076, Tuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Otfried-Mueller-Str. 25, 72076, Tuebingen, Germany
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40
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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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41
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Baldi E, Bucherelli C. Brain sites involved in fear memory reconsolidation and extinction of rodents. Neurosci Biobehav Rev 2015; 53:160-90. [DOI: 10.1016/j.neubiorev.2015.04.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 03/30/2015] [Accepted: 04/06/2015] [Indexed: 12/21/2022]
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Ortiz V, Giachero M, Espejo PJ, Molina VA, Martijena ID. The effect of Midazolam and Propranolol on fear memory reconsolidation in ethanol-withdrawn rats: influence of d-cycloserine. Int J Neuropsychopharmacol 2015; 18:pyu082. [PMID: 25617327 PMCID: PMC4360226 DOI: 10.1093/ijnp/pyu082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Withdrawal from chronic ethanol facilitates the formation of contextual fear memory and delays the onset to extinction, with its retrieval promoting an increase in ethanol consumption. Consequently, manipulations aimed to reduce these aversive memories, may be beneficial in the treatment of alcohol discontinuation symptoms. Related to this, pharmacological memory reconsolidation blockade has received greater attention due to its therapeutic potential. METHODS Here, we examined the effect of post-reactivation amnestic treatments such as Midazolam (MDZ, 3 mg/kg i.p) and Propranolol (PROP, 5 mg/kg i.p) on contextual fear memory reconsolidation in ethanol- withdrawn (ETOH) rats. Next, we examined whether the activation of N-methyl-D-aspartate (NMDA) receptors induced by d-cycloserine (DCS, 5 mg/kg i.p., a NMDA partial agonist) before memory reactivation can facilitate the disruptive effect of PROP and MDZ on fear memory in ETOH rats. RESULTS We observed a resistance to the disruptive effect of both MDZ and PROP following memory reactivation. Although intra-basolateral amygdala (BLA; 1.25 ug/side) and systemic PROP administration attenuated fear memory in DCS pre-treated ETOH rats, DCS/MDZ treatment did not affect memory in these animals. Finally, a decrease of both total and surface protein expression of the α1 GABAA receptor (GABAA-R) subunit in BLA was found in the ETOH rats. CONCLUSIONS Ethanol withdrawal facilitated the formation of fear memory resistant to labilization post-reactivation. DCS administration promoted the disruptive effect of PROP on memory reconsolidation in ETOH rats. The resistance to MDZ's disruptive effect on fear memory reconsolidation may be, at least in part, associated with changes in the GABAA-R composition induced by chronic ethanol administration/withdrawal.
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Affiliation(s)
| | | | | | | | - Irene Delia Martijena
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina (Ms Ortiz, Dr Giachero, Mr Espejo, PharmD, Drs Molina and Martijena)
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Möhler H. The legacy of the benzodiazepine receptor: from flumazenil to enhancing cognition in Down syndrome and social interaction in autism. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 72:1-36. [PMID: 25600365 DOI: 10.1016/bs.apha.2014.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The study of the psychopharmacology of benzodiazepines continues to provide new insights into diverse brain functions related to vigilance, anxiety, mood, epileptiform activity, schizophrenia, cognitive performance, and autism-related social behavior. In this endeavor, the discovery of the benzodiazepine receptor was a key event, as it supplied the primary benzodiazepine drug-target site, provided the molecular link to the allosteric modulation of GABAA receptors and, following the recognition of GABAA receptor subtypes, furnished the platform for future, more selective drug actions. This review has two parts. In a retrospective first part, it acknowledges the contributions to the field made by my collaborators over the years, initially at Hoffmann-La Roche in Basle and later, in academia, at the University and the ETH of Zurich. In the second part, the new frontier of GABA pharmacology, targeting GABAA receptor subtypes, is reviewed with special focus on nonsedative anxiolytics, antidepressants, analgesics, as well as enhancers of cognition in Down syndrome and attenuators of symptoms of autism spectrum disorders. It is encouraging that a clinical trial has been initiated with a partial inverse agonist acting on α5 GABAA receptors in an attempt to alleviate the cognitive deficits in Down syndrome.
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Affiliation(s)
- Hanns Möhler
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; Department of Chemistry and Applied Biosciences, Federal Institute of Technology (ETH), Zurich, Switzerland.
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Singewald N, Schmuckermair C, Whittle N, Holmes A, Ressler KJ. Pharmacology of cognitive enhancers for exposure-based therapy of fear, anxiety and trauma-related disorders. Pharmacol Ther 2014; 149:150-90. [PMID: 25550231 PMCID: PMC4380664 DOI: 10.1016/j.pharmthera.2014.12.004] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 12/24/2014] [Indexed: 12/20/2022]
Abstract
Pathological fear and anxiety are highly debilitating and, despite considerable advances in psychotherapy and pharmacotherapy they remain insufficiently treated in many patients with PTSD, phobias, panic and other anxiety disorders. Increasing preclinical and clinical evidence indicates that pharmacological treatments including cognitive enhancers, when given as adjuncts to psychotherapeutic approaches [cognitive behavioral therapy including extinction-based exposure therapy] enhance treatment efficacy, while using anxiolytics such as benzodiazepines as adjuncts can undermine long-term treatment success. The purpose of this review is to outline the literature showing how pharmacological interventions targeting neurotransmitter systems including serotonin, dopamine, noradrenaline, histamine, glutamate, GABA, cannabinoids, neuropeptides (oxytocin, neuropeptides Y and S, opioids) and other targets (neurotrophins BDNF and FGF2, glucocorticoids, L-type-calcium channels, epigenetic modifications) as well as their downstream signaling pathways, can augment fear extinction and strengthen extinction memory persistently in preclinical models. Particularly promising approaches are discussed in regard to their effects on specific aspects of fear extinction namely, acquisition, consolidation and retrieval, including long-term protection from return of fear (relapse) phenomena like spontaneous recovery, reinstatement and renewal of fear. We also highlight the promising translational value of the preclinial research and the clinical potential of targeting certain neurochemical systems with, for example d-cycloserine, yohimbine, cortisol, and L-DOPA. The current body of research reveals important new insights into the neurobiology and neurochemistry of fear extinction and holds significant promise for pharmacologically-augmented psychotherapy as an improved approach to treat trauma and anxiety-related disorders in a more efficient and persistent way promoting enhanced symptom remission and recovery.
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Affiliation(s)
- N Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria.
| | - C Schmuckermair
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - N Whittle
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - A Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
| | - K J Ressler
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
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45
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Petrini EM, Barberis A. Diffusion dynamics of synaptic molecules during inhibitory postsynaptic plasticity. Front Cell Neurosci 2014; 8:300. [PMID: 25294987 PMCID: PMC4171989 DOI: 10.3389/fncel.2014.00300] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/05/2014] [Indexed: 12/24/2022] Open
Abstract
The plasticity of inhibitory transmission is expected to play a key role in the modulation of neuronal excitability and network function. Over the last two decades, the investigation of the determinants of inhibitory synaptic plasticity has allowed distinguishing presynaptic and postsynaptic mechanisms. While there has been a remarkable progress in the characterization of presynaptically-expressed plasticity of inhibition, the postsynaptic mechanisms of inhibitory long-term synaptic plasticity only begin to be unraveled. At postsynaptic level, the expression of inhibitory synaptic plasticity involves the rearrangement of the postsynaptic molecular components of the GABAergic synapse, including GABAA receptors, scaffold proteins and structural molecules. This implies a dynamic modulation of receptor intracellular trafficking and receptor surface lateral diffusion, along with regulation of the availability and distribution of scaffold proteins. This Review will focus on the mechanisms of the multifaceted molecular reorganization of the inhibitory synapse during postsynaptic plasticity, with special emphasis on the key role of protein dynamics to ensure prompt and reliable activity-dependent adjustments of synaptic strength.
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Affiliation(s)
- Enrica Maria Petrini
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
| | - Andrea Barberis
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
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Pinna G, Rasmusson AM. Ganaxolone improves behavioral deficits in a mouse model of post-traumatic stress disorder. Front Cell Neurosci 2014; 8:256. [PMID: 25309317 PMCID: PMC4161165 DOI: 10.3389/fncel.2014.00256] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/11/2014] [Indexed: 12/14/2022] Open
Abstract
Allopregnanolone and its equipotent stereoisomer, pregnanolone (together termed ALLO), are neuroactive steroids that positively and allosterically modulate the action of gamma-amino-butyric acid (GABA) at GABAA receptors. Levels of ALLO are reduced in the cerebrospinal fluid of female premenopausal patients with post-traumatic stress disorder (PTSD), a severe, neuropsychiatric condition that affects millions, yet is without a consistently effective therapy. This suggests that restoring downregulated brain ALLO levels in PTSD may be beneficial. ALLO biosynthesis is also decreased in association with the emergence of PTSD-like behaviors in socially isolated (SI) mice. Similar to PTSD patients, SI mice also exhibit changes in the frontocortical and hippocampal expression of GABAA receptor subunits, resulting in resistance to benzodiazepine-mediated sedation and anxiolysis. ALLO acts at a larger spectrum of GABAA receptor subunits than benzodiazepines, and increasing corticolimbic ALLO levels in SI mice by injecting ALLO or stimulating ALLO biosynthesis with a selective brain steroidogenic stimulant, such as S-norfluoxetine, at doses far below those that block serotonin reuptake, reduces PTSD-like behavior in these mice. This suggests that synthetic analogs of ALLO, such as ganaxolone, may also improve anxiety, aggression, and other PTSD-like behaviors in the SI mouse model. Consistent with this hypothesis, ganaxolone (3.75–30 mg/kg, s.c.) injected 60 min before testing of SI mice, induced a dose-dependent reduction in aggression toward a same-sex intruder and anxiety-like behavior in an elevated plus maze. The EC50 dose of ganaxolone used in these tests also normalized exaggerated contextual fear conditioning and, remarkably, enhanced fear extinction retention in SI mice. At these doses, ganaxolone failed to change locomotion in an open field test. Therefore, unlike benzodiazepines, ganaxolone at non-sedating concentrations appears to improve dysfunctional emotional behavior associated with deficits in ALLO in mice and may provide an alternative treatment for PTSD patients with deficits in the synthesis of ALLO. Selective serotonin reuptake inhibitors (SSRIs) are the only medications currently approved by the FDA for treatment of PTSD, although they are ineffective in a substantial proportion of PTSD patients. Hence, an ALLO analog such as ganaxolone may offer a therapeutic GABAergic alternative to SSRIs for the treatment of PTSD or other disorders in which ALLO biosynthesis may be impaired.
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Affiliation(s)
- Graziano Pinna
- The Psychiatric Institute, College of Medicine, University of Illinois at Chicago Chicago, IL, USA
| | - Ann M Rasmusson
- VA Boston Healthcare System, Women's Health Science Division of the VA National Center for PTSD, and Boston University School of Medicine Boston, MA, USA
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Abstract
We review recent work on the role of intrinsic amygdala networks in the regulation of classically conditioned defensive behaviors, commonly known as conditioned fear. These new developments highlight how conditioned fear depends on far more complex networks than initially envisioned. Indeed, multiple parallel inhibitory and excitatory circuits are differentially recruited during the expression versus extinction of conditioned fear. Moreover, shifts between expression and extinction circuits involve coordinated interactions with different regions of the medial prefrontal cortex. However, key areas of uncertainty remain, particularly with respect to the connectivity of the different cell types. Filling these gaps in our knowledge is important because much evidence indicates that human anxiety disorders results from an abnormal regulation of the networks supporting fear learning.
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Müller I, Obata K, Richter-Levin G, Stork O. GAD65 haplodeficiency conveys resilience in animal models of stress-induced psychopathology. Front Behav Neurosci 2014; 8:265. [PMID: 25147515 PMCID: PMC4124590 DOI: 10.3389/fnbeh.2014.00265] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/17/2014] [Indexed: 12/19/2022] Open
Abstract
GABAergic mechanisms are critically involved in the control of fear and anxiety, but their role in the development of stress-induced psychopathologies, including post-traumatic stress disorder (PTSD) and mood disorders is not sufficiently understood. We studied these functions in two established mouse models of risk factors for stress-induced psychopathologies employing variable juvenile stress and/or social isolation. A battery of emotional tests in adulthood revealed the induction of contextually generalized fear, anxiety, hyperarousal and depression-like symptoms in these paradigms. These reflect the multitude and complexity of stress effects in human PTSD patients. With factor analysis we were able to identify parameters that reflect these different behavioral domains in stressed animals and thus provide a basis for an integrated scoring of affectedness more closely resembling the clinical situation than isolated parameters. To test the applicability of these models to genetic approaches we further tested the role of GABA using heterozygous mice with targeted mutation of the GABA synthesizing enzyme GAD65 [GAD65(+/−) mice], which show a delayed postnatal increase in tissue GABA content in limbic and cortical brain areas. Unexpectedly, GAD65(+/−) mice did not show changes in exploratory activity regardless of the stressor type and were after the variable juvenile stress procedure protected from the development of contextual generalization in an auditory fear conditioning experiment. Our data demonstrate the complex nature of behavioral alterations in rodent models of stress-related psychopathologies and suggest that GAD65 haplodeficiency, likely through its effect on the postnatal maturation of GABAergic transmission, conveys resilience to some of these stress-induced effects.
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Affiliation(s)
- Iris Müller
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Germany
| | - Kunihiko Obata
- National Institute for Physiological Sciences Okazaki, Aichi, Japan
| | - Gal Richter-Levin
- Department of Neurobiology and Ethology and Department of Psychology, Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Germany ; Center for Behavioural Brain Sciences Magdeburg, Germany
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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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BDNF-TrkB receptor regulation of distributed adult neural plasticity, memory formation, and psychiatric disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:169-92. [PMID: 24484701 DOI: 10.1016/b978-0-12-420170-5.00006-4] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and its single transmembrane receptor, tropomysin-related kinase B (TrkB), are essential for adult synaptic plasticity and the formation of memories. However, there are regional and task-dependent differences underlying differential mechanisms of BDNF-TrkB function in the formation of these memories. Additionally, the BDNF pathway has been implicated in several psychiatric disorders including posttraumatic stress disorder, phobia, and panic disorder. Gaining a better understanding of this pathway and the neurobiology of memory through fundamental research may be helpful to identify effective prevention and treatment approaches both for diseases of memory deficit as well as in cases of enhanced aversive memory, such as in anxiety disorders.
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