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Battaglia S, Di Fazio C, Vicario CM, Avenanti A. Neuropharmacological Modulation of N-methyl-D-aspartate, Noradrenaline and Endocannabinoid Receptors in Fear Extinction Learning: Synaptic Transmission and Plasticity. Int J Mol Sci 2023; 24:ijms24065926. [PMID: 36983000 PMCID: PMC10053024 DOI: 10.3390/ijms24065926] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Learning to recognize and respond to potential threats is crucial for survival. Pavlovian threat conditioning represents a key paradigm for investigating the neurobiological mechanisms of fear learning. In this review, we address the role of specific neuropharmacological adjuvants that act on neurochemical synaptic transmission, as well as on brain plasticity processes implicated in fear memory. We focus on novel neuropharmacological manipulations targeting glutamatergic, noradrenergic, and endocannabinoid systems, and address how the modulation of these neurobiological systems affects fear extinction learning in humans. We show that the administration of N-methyl-D-aspartate (NMDA) agonists and modulation of the endocannabinoid system by fatty acid amide hydrolase (FAAH) inhibition can boost extinction learning through the stabilization and regulation of the receptor concentration. On the other hand, elevated noradrenaline levels dynamically modulate fear learning, hindering long-term extinction processes. These pharmacological interventions could provide novel targeted treatments and prevention strategies for fear-based and anxiety-related disorders.
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Affiliation(s)
- Simone Battaglia
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
- Department of Psychology, University of Turin, 10124 Turin, Italy
| | - Chiara Di Fazio
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
| | - Carmelo M Vicario
- Dipartimento di Scienze Cognitive, Psicologiche, Pedagogiche e Degli Studi Culturali, Università Degli Studi di Messina, 98122 Messina, Italy
| | - Alessio Avenanti
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
- Neuropsicology and Cognitive Neuroscience Research Center (CINPSI Neurocog), Universidad Católica del Maule, Talca 3460000, Chile
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Provencher J, Cernik R, Marin MF. Impact of Stress and Exercise on Fear Extinction. Curr Top Behav Neurosci 2023; 64:157-178. [PMID: 37498495 DOI: 10.1007/7854_2023_432] [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] [Indexed: 07/28/2023]
Abstract
This chapter reviews the literature on the impact of stress and exercise on fear extinction. Given that key brain regions of the fear circuitry (e.g., hippocampus, amygdala and frontal cortex) can be modulated by stress hormones, it is important to investigate how stress influences this process. Laboratory-based studies performed in healthy adults have yielded mixed results, which are most likely attributable to various methodological factors. Among these factors, inter-individual differences modulating the stress response and timing of stressor administration with respect to the task may contribute to this heterogeneity. Given that fear is a core manifestation of various psychopathologies and that exposure-based therapy relies on fear extinction principles, several studies have attempted to assess the role of stress hormones on exposure-based therapy in patients suffering from post-traumatic stress disorder or anxiety disorders. These studies tend to suggest a beneficial impact of stress hormones (through either natural endogenous variations or synthetic administration) on exposure-based therapy as assessed mostly by subjective fear measures. Similar to stress, exercise can have an impact on many physiological and biological systems in humans. Of note, exercise modulates biomarkers such as brain-derived neurotrophic factor (BDNF) and anandamide (EAE) that act on brain regions implicated in the fear circuitry, supporting the importance of studying the impact of exercise on fear extinction. Overall, the results converge and indicate that fear extinction (tested in the laboratory or via exposure-based therapy in clinical populations) can be enhanced with exercise. Further research is needed to understand the mechanisms by which stress and exercise modulate fear learning and extinction processes, as well as to maximize the applicability to clinical contexts.
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Affiliation(s)
- Jessie Provencher
- Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada
- Research Centre of the Institut Universitaire en Santé Mentale de Montréal, Montreal, QC, Canada
| | - Rebecca Cernik
- Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada
- Research Centre of the Institut Universitaire en Santé Mentale de Montréal, Montreal, QC, Canada
| | - Marie-France Marin
- Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada.
- Research Centre of the Institut Universitaire en Santé Mentale de Montréal, Montreal, QC, Canada.
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4
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Merz CJ, Wolf OT. How stress hormones shape memories of fear and anxiety in humans. Neurosci Biobehav Rev 2022; 142:104901. [DOI: 10.1016/j.neubiorev.2022.104901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 11/29/2022]
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Role of noradrenergic arousal for fear extinction processes in rodents and humans. Neurobiol Learn Mem 2022; 194:107660. [PMID: 35870717 DOI: 10.1016/j.nlm.2022.107660] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/29/2022] [Accepted: 07/17/2022] [Indexed: 01/22/2023]
Abstract
Fear extinction is a learning mechanism that is pivotal for the inhibition of fear responses towards cues or contexts that no longer predict the occurrence of a threat. Failure of fear extinction leads to fear expression under safe conditions and is regarded to be a cardinal characteristic of many anxiety-related disorders and posttraumatic stress disorder. Importantly, the neurotransmitter noradrenaline was shown to be a potent modulator of fear extinction. Rodent studies demonstrated that excessive noradrenaline transmission after acute stress opens a time window of vulnerability, in which fear extinction learning results in attenuated long-term extinction success. In contrast, when excessive noradrenergic transmission subsides, well-coordinated noradrenaline transmission is necessary for the formation of a long-lasting extinction memory. In addition, emerging evidence suggests that the neuropeptide corticotropin releasing hormone (CRF), which strongly regulates noradrenaline transmission under conditions of acute stress, also impedes long-term extinction success. Recent rodent work - using sophisticated methods - provides evidence for a hypothetical mechanistic framework of how noradrenaline and CRF dynamically orchestrate the neural fear and extinction circuitry to attenuate or to improve fear extinction and extinction recall. Accordingly, we review the evidence from rodent studies linking noradrenaline and CRF to fear extinction learning and recall and derive the hypothetical mechanistic framework of how different levels of noradrenaline and CRF may create a time window of vulnerability which impedes successful long-term fear extinction. We also address evidence from human studies linking noradrenaline and fear extinction success. Moreover, we accumulate emerging approaches to non-invasively measure and manipulate the noradrenergic system in healthy humans. Finally, we emphasize the importance of future studies to account for sex (hormone) differences when examining the interaction between fear extinction, noradrenaline, and CRF. To conclude, NA's effects on fear extinction recall strongly depend on the arousal levels at the onset of fear extinction learning. Our review aimed at compiling the available (mainly rodent) data in a neurobiological framework, suited to derive testable hypotheses for future work in humans.
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6
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Warren WG, Papagianni EP, Stevenson CW, Stubbendorff C. In it together? The case for endocannabinoid-noradrenergic interactions in fear extinction. Eur J Neurosci 2021; 55:952-970. [PMID: 33759226 DOI: 10.1111/ejn.15200] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/26/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022]
Abstract
Anxiety and trauma-related disorders, such as post-traumatic stress disorder (PTSD), are debilitating mental illnesses with great personal and socioeconomic costs. Examining memory formation and relevant behavioural responding associated with aversive stimuli may improve our understanding of the neurobiology underlying fear memory processing and PTSD treatment. The neurocircuitry underpinning learned fear and its inhibition through extinction is complex, involving synergistic interactions between different neurotransmitter systems in inter-connected brain areas. Endocannabinoid and noradrenergic transmission have both been implicated separately in fear memory processing and PTSD, but potential interactions between these systems in relation to fear extinction have received little attention to date. Their receptors are expressed together in brain areas crucial for fear extinction, which is enhanced by both cannabinoid and noradrenergic receptor activation in these areas. Moreover, cannabinoid signalling modulates the activity of locus coeruleus noradrenaline (NA) neurons and the release of NA in the medial prefrontal cortex, a brain area that is crucial for fear extinction. Interestingly, endocannabinoid-noradrenergic system interactions have been shown to regulate the encoding and retrieval of fear memory. Thus, noradrenergic regulation of fear extinction may also be driven indirectly in part via cannabinoid receptor signalling. In this perspective paper, we collate the available relevant literature and propose a synergistic role for the endocannabinoid and noradrenergic systems in regulating fear extinction, the study of which may further our understanding of the neurobiological substrates of PTSD and its treatment.
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Affiliation(s)
- William G Warren
- School of Biosciences, University of Nottingham, Loughborough, UK
| | | | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Loughborough, UK
| | - Christine Stubbendorff
- School of Biosciences, University of Nottingham, Loughborough, UK.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
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Picó-Pérez M, Alemany-Navarro M, Dunsmoor J, Radua J, Albajes-Eizagirre A, Vervliet B, Cardoner N, Benet O, Harrison B, Soriano-Mas C, Fullana M. Common and distinct neural correlates of fear extinction and cognitive reappraisal: A meta-analysis of fMRI studies. Neurosci Biobehav Rev 2019; 104:102-115. [DOI: 10.1016/j.neubiorev.2019.06.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/22/2019] [Accepted: 06/20/2019] [Indexed: 12/25/2022]
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Velasco ER, Florido A, Milad MR, Andero R. Sex differences in fear extinction. Neurosci Biobehav Rev 2019; 103:81-108. [PMID: 31129235 PMCID: PMC6692252 DOI: 10.1016/j.neubiorev.2019.05.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/08/2019] [Accepted: 05/19/2019] [Indexed: 12/18/2022]
Abstract
Despite the exponential increase in fear research during the last years, few studies have included female subjects in their design. The need to include females arises from the knowledge gap of mechanistic processes underlying the behavioral and neural differences observed in fear extinction. Moreover, the exact contribution of sex and hormones in relation to learning and behavior is still largely unknown. Insights from this field could be beneficial as fear-related disorders are twice as prevalent in women compared to men. Here, we review an up-to-date summary of animal and human studies in adulthood that report sex differences in fear extinction from a structural and functional approach. Furthermore, we describe how these factors could contribute to the observed sex differences in fear extinction during normal and pathological conditions.
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Affiliation(s)
- E R Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - A Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - M R Milad
- Department of Psychiatry, University of Illinois at Chicago, USA
| | - R Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Corporació Sanitaria Parc Taulí, Sabadell, Spain; Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Spain.
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9
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Gerlicher AMV, Tüscher O, Kalisch R. L-DOPA improves extinction memory retrieval after successful fear extinction. Psychopharmacology (Berl) 2019; 236:3401-3412. [PMID: 31243481 PMCID: PMC6892771 DOI: 10.1007/s00213-019-05301-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/05/2019] [Indexed: 11/30/2022]
Abstract
RATIONALE A promising strategy to prevent a return of fear after exposure-based therapy in anxiety disorders is to pharmacologically enhance the extinction memory consolidation presumed to occur after exposure. Accumulating evidence suggests that the effect of a number of pharmacological consolidation enhancers depends on a successful fear reduction during exposure. Here, we employed the dopamine precursor L-DOPA to clarify whether its documented potential to enhance extinction memory consolidation is dependent on successful fear extinction. METHODS In two double-blind, randomized and placebo-controlled experiments (experiment 1: N = 79, experiment 2: N = 32) comprising fear conditioning (day 1), extinction followed by administration of 150 mg L-DOPA or placebo (day 2) and a memory test (day 3) in healthy male adults, conditioned responses were assessed as differential skin conductance responses. We tested whether the effect of L-DOPA on conditioned responses at test depended on conditioned responses at the end of extinction in an experiment with a short (10 trials, experiment 1) and long (25 trials, experiment 2) extinction session. RESULTS In both experiments, the effect of L-DOPA was dependent on conditioned responses at the end of extinction. That is, post-extinction L-DOPA compared to placebo administration reduced conditioned responses at test only in participants showing a complete reduction of conditioned fear at the end of extinction. CONCLUSION The results support the potential use of L-DOPA as a pharmacological adjunct to exposure treatment, but point towards a common boundary condition for pharmacological consolidation enhancers: a successful reduction of fear in the exposure session.
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Affiliation(s)
- A. M. V. Gerlicher
- Neuroimaging Center (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany ,Deutsches Resilienz Zentrum (DRZ), Johannes Gutenberg University Medical Center, Untere Zahlbacher Str. 8, 55131 Mainz, Germany ,Present Address: Department of Clinical Psychology, University of Amsterdam, Nieuwe Achtergracht 129B, 1018 WS Amsterdam, The Netherlands
| | - O. Tüscher
- Deutsches Resilienz Zentrum (DRZ), Johannes Gutenberg University Medical Center, Untere Zahlbacher Str. 8, 55131 Mainz, Germany ,Department of Psychiatry and Psychotherapy, Johannes Gutenberg University Medical Center, Untere Zahlbacher Str. 8, 55131 Mainz, Germany
| | - R. Kalisch
- Neuroimaging Center (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany ,Deutsches Resilienz Zentrum (DRZ), Johannes Gutenberg University Medical Center, Untere Zahlbacher Str. 8, 55131 Mainz, Germany
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10
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Sevenster D, Visser RM, D'Hooge R. A translational perspective on neural circuits of fear extinction: Current promises and challenges. Neurobiol Learn Mem 2018; 155:113-126. [PMID: 29981423 PMCID: PMC6805216 DOI: 10.1016/j.nlm.2018.07.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 06/20/2018] [Accepted: 07/03/2018] [Indexed: 02/07/2023]
Abstract
Fear extinction is the well-known process of fear reduction through repeated re-exposure to a feared stimulus without the aversive outcome. The last two decades have witnessed a surge of interest in extinction learning. First, extinction learning is observed across species, and especially research on rodents has made great strides in characterising the physical substrate underlying extinction learning. Second, extinction learning is considered of great clinical significance since it constitutes a crucial component of exposure treatment. While effective in reducing fear responding in the short term, extinction learning can lose its grip, resulting in a return of fear (i.e., laboratory model for relapse of anxiety symptoms in patients). Optimization of extinction learning is, therefore, the subject of intense investigation. It is thought that the success of extinction learning is, at least partly, determined by the mismatch between what is expected and what actually happens (prediction error). However, while much of our knowledge about the neural circuitry of extinction learning and factors that contribute to successful extinction learning comes from animal models, translating these findings to humans has been challenging for a number of reasons. Here, we present an overview of what is known about the animal circuitry underlying extinction of fear, and the role of prediction error. In addition, we conducted a systematic literature search to evaluate the degree to which state-of-the-art neuroimaging methods have contributed to translating these findings to humans. Results show substantial overlap between networks in animals and humans at a macroscale, but current imaging techniques preclude comparisons at a smaller scale, especially in sub-cortical areas that are functionally heterogeneous. Moreover, human neuroimaging shows the involvement of numerous areas that are not typically studied in animals. Results obtained in research aimed to map the extinction circuit are largely dependent on the methods employed, not only across species, but also across human neuroimaging studies. Directions for future research are discussed.
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Affiliation(s)
- Dieuwke Sevenster
- Laboratory of Biological Psychology, Department of Psychology, KU Leuven, Tiensestraat 102, B-3000 Leuven, Belgium; Clinical Psychology, Utrecht University, Heidelberglaan 1, 3584 CS Utrecht, The Netherlands.
| | - Renée M Visser
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, Department of Psychology, KU Leuven, Tiensestraat 102, B-3000 Leuven, Belgium
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Fullana MA, Albajes-Eizagirre A, Soriano-Mas C, Vervliet B, Cardoner N, Benet O, Radua J, Harrison BJ. Fear extinction in the human brain: A meta-analysis of fMRI studies in healthy participants. Neurosci Biobehav Rev 2018. [PMID: 29530516 DOI: 10.1016/j.neubiorev.2018.03.002] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The study of fear extinction represents an important example of translational neuroscience in psychiatry and promises to improve the understanding and treatment of anxiety and fear-related disorders. We present the results of a set of meta-analyses of human fear extinction studies in healthy participants, conducted with functional magnetic resonance imaging (fMRI) and reporting whole-brain results. Meta-analyses of fear extinction learning primarily implicate consistent activation of brain regions linked to threat appraisal and experience, including the dorsal anterior cingulate and anterior insular cortices. An overlapping anatomical result was obtained from the meta-analysis of extinction recall studies, except when studies directly compared an extinguished threat stimulus to an unextinguished threat stimulus (instead of a safety stimulus). In this latter instance, more consistent activation was observed in dorsolateral and ventromedial prefrontal cortex regions, together with other areas including the hippocampus. While our results partially support the notion of a shared neuroanatomy between human and rodent models of extinction processes, they also encourage an expanded account of the neural basis of human fear extinction.
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Affiliation(s)
- Miquel A Fullana
- FIDMAG Germanes Hospitalàries, CIBERSAM, Sant Boi de Llobregat, Barcelona, Spain; Department of Psychiatry, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | | | - Carles Soriano-Mas
- Department of Psychiatry, Bellvitge University Hospital-IDIBELL, CIBERSAM, Barcelona, Spain; Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Spain
| | - Bram Vervliet
- Center for Excellence on Generalization in Health and Psychopathology, University of KU Leuven, Leuven, Belgium; Department of Psychiatry, Harvard Medical School, Boston, USA; Department of Psychiatry, Massachusetts General Hospital, Boston, USA
| | - Narcís Cardoner
- Department of Psychiatry, Universitat Autònoma de Barcelona, Barcelona, Spain; Depression and Anxiety Unit, Mental Health Department, CIBERSAM, Parc Taulí Sabadell University Hospital, Barcelona, Spain
| | | | - Joaquim Radua
- FIDMAG Germanes Hospitalàries, CIBERSAM, Sant Boi de Llobregat, Barcelona, Spain; Institute of Psychiatry, King's College London, De Crespigny Park, London, UK; Centre for Psychiatric Research and Education, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ben J Harrison
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Level 3, 161 Barry Street, Melbourne, Victoria, Australia.
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Reinstatement of contextual conditioned anxiety in virtual reality and the effects of transcutaneous vagus nerve stimulation in humans. Sci Rep 2017; 7:17886. [PMID: 29263408 PMCID: PMC5738426 DOI: 10.1038/s41598-017-18183-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/05/2017] [Indexed: 11/09/2022] Open
Abstract
Since exposure therapy for anxiety disorders incorporates extinction of contextual anxiety, relapses may be due to reinstatement processes. Animal research demonstrated more stable extinction memory and less anxiety relapse due to vagus nerve stimulation (VNS). We report a valid human three-day context conditioning, extinction and return of anxiety protocol, which we used to examine effects of transcutaneous VNS (tVNS). Seventy-five healthy participants received electric stimuli (unconditioned stimuli, US) during acquisition (Day1) when guided through one virtual office (anxiety context, CTX+) but never in another (safety context, CTX-). During extinction (Day2), participants received tVNS, sham, or no stimulation and revisited both contexts without US delivery. On Day3, participants received three USs for reinstatement followed by a test phase. Successful acquisition, i.e. startle potentiation, lower valence, higher arousal, anxiety and contingency ratings in CTX+ versus CTX-, the disappearance of these effects during extinction, and successful reinstatement indicate validity of this paradigm. Interestingly, we found generalized reinstatement in startle responses and differential reinstatement in valence ratings. Altogether, our protocol serves as valid conditioning paradigm. Reinstatement effects indicate different anxiety networks underlying physiological versus verbal responses. However, tVNS did neither affect extinction nor reinstatement, which asks for validation and improvement of the stimulation protocol.
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13
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Sperl MFJ, Panitz C, Hermann C, Mueller EM. A pragmatic comparison of noise burst and electric shock unconditioned stimuli for fear conditioning research with many trials. Psychophysiology 2016; 53:1352-65. [PMID: 27286734 DOI: 10.1111/psyp.12677] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 04/28/2016] [Indexed: 01/01/2023]
Abstract
Several methods that are promising for studying the neurophysiology of fear conditioning (e.g., EEG, MEG) require a high number of trials to achieve an adequate signal-to-noise ratio. While electric shock and white noise burst are among the most commonly used unconditioned stimuli (US) in conventional fear conditioning studies with few trials, it is unknown whether these stimuli are equally well suited for paradigms with many trials. Here, N = 32 participants underwent a 260-trial differential fear conditioning and extinction paradigm with a 240-trial recall test 24 h later and neutral faces as conditioned stimuli. In a between-subjects design, either white noise bursts (n = 16) or electric shocks (n = 16) served as US, and intensities were determined using the most common procedure for each US (i.e., a fixed 95 dB noise burst and a work-up procedure for electric shocks, respectively). In addition to differing US types, groups also differed in closely linked US-associated characteristics (e.g., calibration methods, stimulus intensities, timing). Subjective ratings (arousal/valence), skin conductance, and evoked heart period changes (i.e., fear bradycardia) indicated more reliable, extinction-resistant, and stable conditioning in the white noise burst versus electric shock group. In fear conditioning experiments where many trials are presented, white noise burst should serve as US.
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Affiliation(s)
- Matthias F J Sperl
- Faculty of Psychology, Personality Psychology and Assessment, University of Marburg, Marburg, Germany.,Faculty of Psychology and Sports Science, Clinical Psychology and Psychotherapy, University of Giessen, Giessen, Germany
| | - Christian Panitz
- Faculty of Psychology, Personality Psychology and Assessment, University of Marburg, Marburg, Germany.,Faculty of Psychology and Sports Science, Clinical Psychology and Psychotherapy, University of Giessen, Giessen, Germany
| | - Christiane Hermann
- Faculty of Psychology and Sports Science, Clinical Psychology and Psychotherapy, University of Giessen, Giessen, Germany
| | - Erik M Mueller
- Faculty of Psychology, Personality Psychology and Assessment, University of Marburg, Marburg, Germany.,Faculty of Psychology and Sports Science, Clinical Psychology and Psychotherapy, University of Giessen, Giessen, Germany
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14
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Golkar A, Haaker J, Selbing I, Olsson A. Neural signals of vicarious extinction learning. Soc Cogn Affect Neurosci 2016; 11:1541-9. [PMID: 27278792 DOI: 10.1093/scan/nsw068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 05/13/2016] [Indexed: 01/10/2023] Open
Abstract
Social transmission of both threat and safety is ubiquitous, but little is known about the neural circuitry underlying vicarious safety learning. This is surprising given that these processes are critical to flexibly adapt to a changeable environment. To address how the expression of previously learned fears can be modified by the transmission of social information, two conditioned stimuli (CS + s) were paired with shock and the third was not. During extinction, we held constant the amount of direct, non-reinforced, exposure to the CSs (i.e. direct extinction), and critically varied whether another individual-acting as a demonstrator-experienced safety (CS + vic safety) or aversive reinforcement (CS + vic reinf). During extinction, ventromedial prefrontal cortex (vmPFC) responses to the CS + vic reinf increased but decreased to the CS + vic safety This pattern of vmPFC activity was reversed during a subsequent fear reinstatement test, suggesting a temporal shift in the involvement of the vmPFC. Moreover, only the CS + vic reinf association recovered. Our data suggest that vicarious extinction prevents the return of conditioned fear responses, and that this efficacy is reflected by diminished vmPFC involvement during extinction learning. The present findings may have important implications for understanding how social information influences the persistence of fear memories in individuals suffering from emotional disorders.
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Affiliation(s)
- Armita Golkar
- Department of Clinical Neuroscience, Karolinska Institutet, Nobels Väg 11, Stockholm 17177, Sweden, Department of Psychology, University of Amsterdam
| | - Jan Haaker
- Department of Clinical Neuroscience, Karolinska Institutet, Nobels Väg 11, Stockholm 17177, Sweden
| | - Ida Selbing
- Department of Clinical Neuroscience, Karolinska Institutet, Nobels Väg 11, Stockholm 17177, Sweden
| | - Andreas Olsson
- Department of Clinical Neuroscience, Karolinska Institutet, Nobels Väg 11, Stockholm 17177, Sweden
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15
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Stockhorst U, Antov MI. Modulation of Fear Extinction by Stress, Stress Hormones and Estradiol: A Review. Front Behav Neurosci 2016; 9:359. [PMID: 26858616 PMCID: PMC4726806 DOI: 10.3389/fnbeh.2015.00359] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/14/2015] [Indexed: 12/25/2022] Open
Abstract
Fear acquisition and extinction are valid models for the etiology and treatment of anxiety, trauma- and stressor-related disorders. These disorders are assumed to involve aversive learning under acute and/or chronic stress. Importantly, fear conditioning and stress share common neuronal circuits. The stress response involves multiple changes interacting in a time-dependent manner: (a) the fast first-wave stress response [with central actions of noradrenaline, dopamine, serotonin, corticotropin-releasing hormone (CRH), plus increased sympathetic tone and peripheral catecholamine release] and (b) the second-wave stress response [with peripheral release of glucocorticoids (GCs) after activation of the hypothalamus-pituitary-adrenocortical (HPA) axis]. Control of fear during extinction is also sensitive to these stress-response mediators. In the present review, we will thus examine current animal and human data, addressing the role of stress and single stress-response mediators for successful acquisition, consolidation and recall of fear extinction. We report studies using pharmacological manipulations targeting a number of stress-related neurotransmitters and neuromodulators [monoamines, opioids, endocannabinoids (eCBs), neuropeptide Y, oxytocin, GCs] and behavioral stress induction. As anxiety, trauma- and stressor-related disorders are more common in women, recent research focuses on female sex hormones and identifies a potential role for estradiol in fear extinction. We will thus summarize animal and human data on the role of estradiol and explore possible interactions with stress or stress-response mediators in extinction. This also aims at identifying time-windows of enhanced (or reduced) sensitivity for fear extinction, and thus also for successful exposure therapy.
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Affiliation(s)
- Ursula Stockhorst
- Experimental Psychology II and Biological Psychology, Institute of Psychology, University of OsnabrückOsnabrück, Germany
| | - Martin I. Antov
- Experimental Psychology II and Biological Psychology, Institute of Psychology, University of OsnabrückOsnabrück, Germany
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16
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Haaker J, Lonsdorf TB, Kalisch R. Effects of post-extinction l-DOPA administration on the spontaneous recovery and reinstatement of fear in a human fMRI study. Eur Neuropsychopharmacol 2015; 25:1544-55. [PMID: 26238968 DOI: 10.1016/j.euroneuro.2015.07.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 04/29/2015] [Accepted: 07/14/2015] [Indexed: 12/29/2022]
Abstract
Relapse is a pertinent problem in the treatment of anxiety disorders. In the laboratory, relapse is modeled as return of conditioned fear responses after successful fear extinction and is explained by insufficient retrieval and/or expression of the fear-inhibitory extinction memory that is generated during extinction learning. We have shown in mice and humans that return of fear can be prevented by administration of a single dose of the dopamine precursor l-3,4-dihydroxyphenylalanine (l-DOPA) immediately after extinction. In mice, this effect could be attributed to an enhancement of extinction memory consolidation. In our human study, we could not exclude that l-DOPA might have acted by interfering with the consolidation of the original fear memory. In the present study, we therefore used a combined differential cue and context conditioning paradigm where initial fear conditioning and extinction were conducted one day apart, in analogy to previous mouse studies. l-DOPA (N=21) or placebo (N=19) were administered after extinction, precluding any action on fear memory consolidation. In the return-of-fear test conducted one week later, drug effects on conditioned skin conductance responses were absent. However, we found evidence indicative of reduced neural activity, measured with functional magnetic resonance imaging (fMRI), in the l-DOPA group in areas related to conditioned fear and return of fear (amygdala, posterior hippocampus) and enhanced activity in a key area of extinction retrieval/expression (ventromedial prefrontal cortex), relative to placebo controls. These findings require further corroboration in additional experiments. Implications for further investigations on the role of the dopamine system in extinction and on the neuropharmacological augmentation of extinction-based therapies are discussed.
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Affiliation(s)
- Jan Haaker
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Karolinska Institutet, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Tina B Lonsdorf
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Raffael Kalisch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Neuroimaging Center (NIC), Focus Program Translational Neuroscience, Johannes Gutenberg University Medical Center Mainz, Germany
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André MAE, Wolf OT, Manahan-Vaughan D. Beta-adrenergic receptors support attention to extinction learning that occurs in the absence, but not the presence, of a context change. Front Behav Neurosci 2015; 9:125. [PMID: 26074793 PMCID: PMC4444826 DOI: 10.3389/fnbeh.2015.00125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/29/2015] [Indexed: 11/13/2022] Open
Abstract
The noradrenergic (NA)-system is an important regulator of cognitive function. It contributes to extinction learning (EL), and in disorders where EL is impaired NA-dysfunction has been postulated. We explored whether NA acting on beta-adrenergic-receptors (β-AR), regulates EL that depends on context, but is not fear-associated. We assessed behavior in an "AAA" or "ABA" paradigm: rats were trained for 3 days in a T-maze (context-A) to learn that a reward is consistently found in the goal arm, despite low reward probability. This was followed on day 4 by EL (unrewarded), whereby in the ABA-paradigm, EL was reinforced by a context change (B), and in the AAA-paradigm, no context change occurred. On day 5, re-exposure to the A-context (unrewarded) occurred. Typically, in control "AAA" animals EL occurred on day 4 that progressed further on day 5. In control "ABA" animals, EL also occurred on day 4, followed by renewal of the previously learned (A) behavior on day 5, that was succeeded (on day 5) by extinction of this behavior, as the animals realised that no food reward would be given. Treatment with the β-AR-antagonist, propranolol, prior to EL on day 4, impaired EL in the AAA-paradigm. In the "ABA" paradigm, antagonist treatment on day 4, had no effect on extinction that was reinforced by a context change (B). Furthermore, β-AR-antagonism prior to renewal testing (on day 5) in the ABA-paradigm, resulted in normal renewal behavior, although subsequent extinction of responses during day 5 was prevented by the antagonist. Thus, under both treatment conditions, β-AR-antagonism prevented extinction of the behavior learned in the "A" context. β-AR-blockade during an overt context change did not prevent EL, whereas β-AR were required for EL in an unchanging context. These data suggest that β-AR may support EL by reinforcing attention towards relevant changes in the previously learned experience, and that this process supports extinction learning in constant-context conditions.
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Affiliation(s)
| | - Oliver T Wolf
- International Graduate School for Neuroscience, Ruhr University Bochum Bochum, Germany ; Faculty of Psychology, Department of Cognitive Psychology, Ruhr University Bochum Bochum, Germany
| | - Denise Manahan-Vaughan
- International Graduate School for Neuroscience, Ruhr University Bochum Bochum, Germany ; Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany
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18
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Haaker J, Golkar A, Hermans D, Lonsdorf TB. A review on human reinstatement studies: an overview and methodological challenges. Learn Mem 2014; 21:424-40. [PMID: 25128533 PMCID: PMC4138360 DOI: 10.1101/lm.036053.114] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 06/17/2014] [Indexed: 12/19/2022]
Abstract
In human research, studies of return of fear (ROF) phenomena, and reinstatement in particular, began only a decade ago and recently are more widely used, e.g., as outcome measures for fear/extinction memory manipulations (e.g., reconsolidation). As reinstatement research in humans is still in its infancy, providing an overview of its stability and boundary conditions and summarizing methodological challenges is timely to foster fruitful future research. As a translational endeavor, clarifying the circumstances under which (experimental) reinstatement occurs may offer a first step toward understanding relapse as a clinical phenomenon and pave the way for the development of new pharmacological or behavioral ways to prevent ROF. The current state of research does not yet allow pinpointing these circumstances in detail and we hope this review will aid the research field to advance in this direction. As an introduction, we begin with a synopsis of rodent work on reinstatement and theories that have been proposed to explain the findings. The review however mainly focuses on reinstatement in humans. We first describe details and variations of the experimental setup in reinstatement studies in humans and give a general overview of results. We continue with a compilation of possible experimental boundary conditions and end with the role of individual differences and behavioral and/or pharmacological manipulations. Furthermore, we compile important methodological and design details on the published studies in humans and end with open research questions and some important methodological and design recommendations as a guide for future research.
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Affiliation(s)
- Jan Haaker
- Institute for Systems Neuroscience, University Hospital Hamburg-Eppendorf, 20246 Hamburg, Germany Karolinska Institute, Department of Clinical Neuroscience, 171 77 Stockholm, Sweden
| | - Armita Golkar
- Karolinska Institute, Department of Clinical Neuroscience, 171 77 Stockholm, Sweden
| | - Dirk Hermans
- Faculty of Psychology and Educational Sciences, University of Leuven, 3000 Leuven, Belgium
| | - Tina B Lonsdorf
- Institute for Systems Neuroscience, University Hospital Hamburg-Eppendorf, 20246 Hamburg, Germany
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19
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Bulganin L, Bach DR, Wittmann BC. Prior fear conditioning and reward learning interact in fear and reward networks. Front Behav Neurosci 2014; 8:67. [PMID: 24624068 PMCID: PMC3940965 DOI: 10.3389/fnbeh.2014.00067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 02/17/2014] [Indexed: 01/22/2023] Open
Abstract
The ability to flexibly adapt responses to changes in the environment is important for survival. Previous research in humans separately examined the mechanisms underlying acquisition and extinction of aversive and appetitive conditioned responses. It is yet unclear how aversive and appetitive learning interact on a neural level during counterconditioning in humans. This functional magnetic resonance imaging (fMRI) study investigated the interaction of fear conditioning and subsequent reward learning. In the first phase (fear acquisition), images predicted aversive electric shocks or no aversive outcome. In the second phase (counterconditioning), half of the CS+ and CS− were associated with monetary reward in the absence of electric stimulation. The third phase initiated reinstatement of fear through presentation of electric shocks, followed by CS presentation in the absence of shock or reward. Results indicate that participants were impaired at learning the reward contingencies for stimuli previously associated with shock. In the counterconditioning phase, prior fear association interacted with reward representation in the amygdala, where activation was decreased for rewarded compared to unrewarded CS− trials, while there was no reward-related difference in CS+ trials. In the reinstatement phase, an interaction of previous fear association and previous reward status was observed in a reward network consisting of substantia nigra/ventral tegmental area (SN/VTA), striatum and orbitofrontal cortex (OFC), where activation was increased by previous reward association only for CS− but not for CS+ trials. These findings suggest that during counterconditioning, prior fear conditioning interferes with reward learning, subsequently leading to lower activation of the reward network.
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Affiliation(s)
- Lisa Bulganin
- Department of Psychology and Sports Science, University of Giessen Giessen, Germany
| | - Dominik R Bach
- Psychiatric Hospital, University of Zurich Zurich, Switzerland ; Wellcome Trust Centre for Neuroimaging, University College London London, UK
| | - Bianca C Wittmann
- Department of Psychology and Sports Science, University of Giessen Giessen, Germany
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Lonsdorf TB, Haaker J, Kalisch R. Long-term expression of human contextual fear and extinction memories involves amygdala, hippocampus and ventromedial prefrontal cortex: a reinstatement study in two independent samples. Soc Cogn Affect Neurosci 2014; 9:1973-83. [PMID: 24493848 DOI: 10.1093/scan/nsu018] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human context conditioning studies have focused on acquisition and extinction. Subsequent long-term changes in fear behaviors not only depend on associative learning processes during those phases but also on memory consolidation processes and the later ability to retrieve and express fear and extinction memories. Clinical theories explain relapse after successful exposure-based treatment with return of fear memories and remission with stable extinction memory expression. We probed contextual fear and extinction memories 1 week (Day8) after conditioning (Day1) and subsequent extinction (Day2) by presenting conditioned contexts before (Test1) and after (Test2) a reinstatement manipulation. We find consistent activation patterns in two independent samples: activation of a subgenual part of the ventromedial prefrontal cortex before reinstatement (Test1) and (albeit with different temporal profiles between samples) of the amygdala after reinstatement (Test2) as well as up-regulation of anterior hippocampus activity after reinstatement (Test2 > Test1). These areas have earlier been implicated in the expression of cued extinction and fear memories. The present results suggest a general role for these structures in defining the balance between fear and extinction memories, independent of the conditioning mode. The results are discussed in the light of hypotheses implicating the anterior hippocampus in the processing of situational ambiguity.
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Affiliation(s)
- Tina B Lonsdorf
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany and Neuroimaging Center Mainz (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany t.lonsdorf@uke
| | - Jan Haaker
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany and Neuroimaging Center Mainz (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Raffael Kalisch
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany and Neuroimaging Center Mainz (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany and Neuroimaging Center Mainz (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131 Mainz, Germany
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