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Ahlbrand R, Wilson A, Woller P, Sachdeva Y, Lai J, Davis N, Wiggins J, Sah R. Sex-specific threat responding and neuronal engagement in carbon dioxide associated fear and extinction: Noradrenergic involvement in female mice. Neurobiol Stress 2024; 30:100617. [PMID: 38433995 PMCID: PMC10907837 DOI: 10.1016/j.ynstr.2024.100617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024] Open
Abstract
Difficulty in appropriately responding to threats is a key feature of psychiatric disorders, especially fear-related conditions such as panic disorder (PD) and posttraumatic stress disorder (PTSD). Most prior work on threat and fear regulation involves exposure to external threatful cues. However, fear can also be triggered by aversive, within-the-body, sensations. This interoceptive signaling of fear is highly relevant to PD and PTSD but is not well understood, especially in the context of sex. Using female and male mice, the current study investigated fear-associated spontaneous and conditioned behaviors to carbon dioxide (CO2) inhalation, a potent interoceptive threat that induces fear and panic. We also investigated whether behavioral sensitivity to CO2 is associated with delayed PTSD-relevant behaviors. CO2 evoked heterogenous freezing behaviors in both male and female animals. However, active, rearing behavior was significantly reduced in CO2-exposed male but not female mice. Interestingly, behavioral sensitivity to CO2 was associated with compromised fear extinction, independent of sex. However, in comparison to CO2-exposed males, females elicited less freezing and higher rearing during extinction suggesting an engagement of active versus passive defensive coping. Persistent neuronal activation marker ΔFosB immuno-mapping revealed attenuated engagement of infralimbic-prefrontal areas in both sexes but higher activation of brain stem locus coeruleus (LC) area in females. Inter-regional co-activation mapping revealed sex-independent disruptions in the infralimbic-amygdala associations but altered LC associations only in CO2-exposed female mice. Lastly, dopamine β hydroxylase positive (DβH + ve) noradrenergic neuronal cell counts in the LC correlated with freezing and rearing behaviors during CO2 inhalation and extinction only in female but not male mice. Collectively, these data provide evidence for higher active defensive responding to interoceptive threat CO2-associated fear in females that may stem from increased recruitment of the brainstem noradrenergic system. Our findings reveal distinct contributory mechanisms that may promote sex differences in fear and panic associated pathologies.
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Affiliation(s)
- Rebecca Ahlbrand
- Department of Pharmacology and Systems Physiology, University of Cincinnati, USA
- Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Allison Wilson
- Neuroscience Undergraduate Program, University of Cincinnati, USA
| | - Patrick Woller
- Neuroscience Graduate Program, University of Cincinnati, USA
| | - Yuv Sachdeva
- Department of Pharmacology and Systems Physiology, University of Cincinnati, USA
| | - Jayden Lai
- Department of Pharmacology and Systems Physiology, University of Cincinnati, USA
| | - Nikki Davis
- Neuroscience Undergraduate Program, University of Cincinnati, USA
| | - James Wiggins
- Neuroscience Undergraduate Program, University of Cincinnati, USA
| | - Renu Sah
- Department of Pharmacology and Systems Physiology, University of Cincinnati, USA
- Neuroscience Graduate Program, University of Cincinnati, USA
- Veterans Affairs Medical Center, Cincinnati, OH, USA
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2
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Raskin M, Keller NE, Agee LA, Shumake J, Smits JA, Telch MJ, Otto MW, Lee HJ, Monfils MH. Carbon Dioxide Reactivity Differentially Predicts Fear Expression After Extinction and Retrieval-Extinction in Rats. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100310. [PMID: 38680941 PMCID: PMC11047292 DOI: 10.1016/j.bpsgos.2024.100310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/11/2024] [Accepted: 03/11/2024] [Indexed: 05/01/2024] Open
Abstract
Background Cues present during a traumatic event may result in persistent fear responses. These responses can be attenuated through extinction learning, a core component of exposure therapy. Exposure/extinction is effective for some people, but not all. We recently demonstrated that carbon dioxide (CO2) reactivity predicts fear extinction memory and orexin activation and that orexin activation predicts fear extinction memory, which suggests that a CO2 challenge may enable identification of whether an individual is a good candidate for an extinction-based approach. Another method to attenuate conditioned responses, retrieval-extinction, renders the original associative memory labile via distinct neural mechanisms. The purpose of the current study was to examine whether we could replicate previous findings that retrieval-extinction is more effective than extinction at preventing the return of fear and that CO2 reactivity predicts fear memory after extinction. We also examined whether CO2 reactivity predicts fear memory after retrieval-extinction. Methods Male rats first underwent a CO2 challenge and fear conditioning and were assigned to receive either standard extinction (n = 28) or retrieval-extinction (n = 28). Then, they underwent a long-term memory (LTM) test and a reinstatement test. Results We found that retrieval-extinction resulted in lower freezing during extinction, LTM, and reinstatement than standard extinction. Using the best subset approach to linear regression, we found that CO2 reactivity predicted LTM after extinction and also predicted LTM after retrieval-extinction, although to a lesser degree. Conclusions CO2 reactivity could be used as a screening tool to determine whether an individual may be a good candidate for an extinction-based therapeutic approach.
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Affiliation(s)
- Marissa Raskin
- Institute for Neuroscience, University of Texas at Austin, Austin, Texas
| | - Nicole E. Keller
- Institute for Neuroscience, University of Texas at Austin, Austin, Texas
| | - Laura A. Agee
- Department of Neuroscience, University of Texas at Austin, Austin, Texas
| | - Jason Shumake
- Department of Psychology, University of Texas at Austin, Austin, Texas
| | - Jasper A.J. Smits
- Department of Psychology, University of Texas at Austin, Austin, Texas
| | - Michael J. Telch
- Department of Psychology, University of Texas at Austin, Austin, Texas
| | - Michael W. Otto
- Department of Psychological & Brain Sciences, Boston University, Boston, Massachusetts
| | - Hongjoo J. Lee
- Institute for Neuroscience, University of Texas at Austin, Austin, Texas
- Department of Psychology, University of Texas at Austin, Austin, Texas
| | - Marie-H. Monfils
- Institute for Neuroscience, University of Texas at Austin, Austin, Texas
- Department of Psychology, University of Texas at Austin, Austin, Texas
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3
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Sierra RO, Pedraza LK, Barcsai L, Pejin A, Li Q, Kozák G, Takeuchi Y, Nagy AJ, Lőrincz ML, Devinsky O, Buzsáki G, Berényi A. Closed-loop brain stimulation augments fear extinction in male rats. Nat Commun 2023; 14:3972. [PMID: 37407557 DOI: 10.1038/s41467-023-39546-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 06/16/2023] [Indexed: 07/07/2023] Open
Abstract
Dysregulated fear reactions can result from maladaptive processing of trauma-related memories. In post-traumatic stress disorder (PTSD) and other psychiatric disorders, dysfunctional extinction learning prevents discretization of trauma-related memory engrams and generalizes fear responses. Although PTSD may be viewed as a memory-based disorder, no approved treatments target pathological fear memory processing. Hippocampal sharp wave-ripples (SWRs) and concurrent neocortical oscillations are scaffolds to consolidate contextual memory, but their role during fear processing remains poorly understood. Here, we show that closed-loop, SWR triggered neuromodulation of the medial forebrain bundle (MFB) can enhance fear extinction consolidation in male rats. The modified fear memories became resistant to induced recall (i.e., 'renewal' and 'reinstatement') and did not reemerge spontaneously. These effects were mediated by D2 receptor signaling-induced synaptic remodeling in the basolateral amygdala. Our results demonstrate that SWR-triggered closed-loop stimulation of the MFB reward system enhances extinction of fearful memories and reducing fear expression across different contexts and preventing excessive and persistent fear responses. These findings highlight the potential of neuromodulation to augment extinction learning and provide a new avenue to develop treatments for anxiety disorders.
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Affiliation(s)
- Rodrigo Ordoñez Sierra
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Lizeth Katherine Pedraza
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Lívia Barcsai
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Andrea Pejin
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Qun Li
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Gábor Kozák
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Yuichi Takeuchi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- Department of Biopharmaceutical Sciences and Pharmacy, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Anett J Nagy
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Magor L Lőrincz
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, Szeged, 6726, Hungary
- Neuroscience Division, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Orrin Devinsky
- Department of Neurology, NYU Langone Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - György Buzsáki
- Neuroscience Institute, New York University, New York, NY, 10016, USA
- Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Antal Berényi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary.
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary.
- Neunos Inc, Boston, MA, 02108, USA.
- Neuroscience Institute, New York University, New York, NY, 10016, USA.
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Raskin M, Malone C, Hilz EN, Smits JAJ, Telch MJ, Otto MW, Shumake J, Lee HJ, Monfils MH. CO 2 reactivity is associated with individual differences in appetitive extinction memory. Physiol Behav 2023; 266:114183. [PMID: 37031791 PMCID: PMC10840099 DOI: 10.1016/j.physbeh.2023.114183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/17/2023] [Accepted: 04/04/2023] [Indexed: 04/11/2023]
Abstract
Pavlovian conditioning can underly the maladaptive behaviors seen in psychiatric disorders such as anxiety and addiction. In both the lab and the clinic, these responses can be attenuated through extinction learning, but often return with the passage of time, stress, or a change in context. Extinction to fear and reward cues are both subject to these return of behavior phenomena and have overlap in neurocircuitry, yet it is unknown whether they share any common predictors. The orexin system has been implicated in both fear and appetitive extinction and can be activated through a CO2 challenge. We previously found that behavioral CO2 reactivity predicts fear extinction and orexin activation. Here, we sought to extend our previous findings to determine whether CO2 reactivity might also predict extinction memory for appetitive light-food conditioning. We find that the same subcomponent of behavioral CO2 reactivity that predicted fear extinction also predicts appetitive extinction, but in the opposite direction. We show evidence that this subcomponent remains stable across two CO2 challenges, suggesting it may be a stable trait of both behavioral CO2 reactivity and appetitive extinction phenotype. Our findings further the possibility for CO2 reactivity to be used as a transdiagnostic screening tool to determine whether an individual would be a good candidate for exposure therapy.
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Affiliation(s)
- Marissa Raskin
- The University of Texas at Austin, Institute for Neuroscience, United States
| | - Cassidy Malone
- The University of Texas at Austin, Department of Psychology, United States
| | - Emily N Hilz
- The University of Texas at Austin, Department of Psychology, United States
| | - Jasper A J Smits
- The University of Texas at Austin, Department of Psychology, United States; The University of Texas at Austin, Institute for Mental Health Research, United States
| | - Michael J Telch
- The University of Texas at Austin, Department of Psychology, United States; The University of Texas at Austin, Institute for Mental Health Research, United States
| | | | - Jason Shumake
- The University of Texas at Austin, Department of Psychology, United States; The University of Texas at Austin, Institute for Mental Health Research, United States
| | - Hongjoo J Lee
- The University of Texas at Austin, Institute for Neuroscience, United States; The University of Texas at Austin, Department of Psychology, United States
| | - Marie-H Monfils
- The University of Texas at Austin, Institute for Neuroscience, United States; The University of Texas at Austin, Department of Psychology, United States; The University of Texas at Austin, Institute for Mental Health Research, United States.
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5
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Smith KA, Raskin MR, Donovan MH, Raghunath V, Mansoorshahi S, Telch MJ, Shumake J, Noble-Haeusslein LJ, Monfils MH. Examining the long-term effects of traumatic brain injury on fear extinction in male rats. Front Behav Neurosci 2023; 17:1206073. [PMID: 37397129 PMCID: PMC10313105 DOI: 10.3389/fnbeh.2023.1206073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/26/2023] [Indexed: 07/04/2023] Open
Abstract
There is a strong association between traumatic brain injuries (TBIs) and the development of psychiatric disorders, including post-traumatic stress disorder (PTSD). Exposure-based therapy is a first-line intervention for individuals who suffer from PTSD and other anxiety-related disorders; however, up to 50% of individuals with PTSD do not respond well to this approach. Fear extinction, a core mechanism underlying exposure-based therapy, is a procedure in which a repeated presentation of a conditioned stimulus in the absence of an unconditioned stimulus leads to a decrease in fear expression, and is a useful tool to better understand exposure-based therapy. Identifying predictors of extinction would be useful in developing alternative treatments for the non-responders. We recently found that CO2 reactivity predicts extinction phenotypes in rats, likely through the activation of orexin receptors in the lateral hypothalamus. While studies have reported mixed results in extinction of fear after TBI, none have examined the long-term durability of this phenotype in the more chronically injured brain. Here we tested the hypothesis that TBI results in a long-term deficit in fear extinction, and that CO2 reactivity would be predictive of this extinction phenotype. Isoflurane-anesthetized adult male rats received TBI (n = 59) (produced by a controlled cortical impactor) or sham surgery (n = 29). One month post-injury or sham surgery, rats underwent a CO2 or air challenge, followed by fear conditioning, extinction, and fear expression testing. TBI rats exposed to CO2 (TBI-CO2) showed no difference during extinction or fear expression relative to shams exposed to CO2 (sham-CO2). However, TBI-CO2 rats, showed significantly better fear expression than TBI rats exposed to air (TBI-air). In contrast to previous findings, we observed no relationship between CO2 reactivity and post-extinction fear expression in either the sham or TBI rats. However, compared to the previously observed naïve sample, we observed more variability in post-extinction fear expression but a very similar distribution of CO2 reactivity in the current sample. Isoflurane anesthesia may lead to interoceptive threat habituation, possibly via action on orexin receptors in the lateral hypothalamus, and may interact with CO2 exposure, resulting in enhanced extinction. Future work will directly test this possibility.
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Affiliation(s)
- K. A. Smith
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - M. R. Raskin
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - M. H. Donovan
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, United States
| | - V. Raghunath
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - S. Mansoorshahi
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - M. J. Telch
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
- Institute of Mental Health Research, The University of Texas at Austin, Austin, TX, United States
| | - J. Shumake
- Institute of Mental Health Research, The University of Texas at Austin, Austin, TX, United States
| | - L. J. Noble-Haeusslein
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, United States
| | - M. H. Monfils
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
- Institute of Mental Health Research, The University of Texas at Austin, Austin, TX, United States
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6
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Ten-Blanco M, Flores Á, Cristino L, Pereda-Pérez I, Berrendero F. Targeting the orexin/hypocretin system for the treatment of neuropsychiatric and neurodegenerative diseases: from animal to clinical studies. Front Neuroendocrinol 2023; 69:101066. [PMID: 37015302 DOI: 10.1016/j.yfrne.2023.101066] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/15/2023] [Accepted: 03/30/2023] [Indexed: 04/06/2023]
Abstract
Orexins (also known as hypocretins) are neuropeptides located exclusively in hypothalamic neurons that have extensive projections throughout the central nervous system and bind two different G protein-coupled receptors (OX1R and OX2R). Since its discovery in 1998, the orexin system has gained the interest of the scientific community as a potential therapeutic target for the treatment of different pathological conditions. Considering previous basic science research, a dual orexin receptor antagonist, suvorexant, was the first orexin agent to be approved by the US Food and Drug Administration to treat insomnia. In this review, we discuss and update the main preclinical and human studies involving the orexin system with several psychiatric and neurodegenerative diseases. This system constitutes a nice example of how basic scientific research driven by curiosity can be the best route to the generation of new and powerful pharmacological treatments.
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Affiliation(s)
- Marc Ten-Blanco
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - África Flores
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Neurosciences Institute, University of Barcelona and Bellvitge University Hospital-IDIBELL, 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy
| | - Inmaculada Pereda-Pérez
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Fernando Berrendero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain.
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7
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Raskin M, Monfils MH. Reconsolidation and Fear Extinction: An Update. Curr Top Behav Neurosci 2023; 64:307-333. [PMID: 37563489 DOI: 10.1007/7854_2023_438] [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: 08/12/2023]
Abstract
Fear memories can be updated behaviorally by delivering extinction trials during the reconsolidation window, which results in a persistent attenuation of fear memories (Monfils et al., Science 324:951-955, 2009). This safe and non-invasive paradigm, termed retrieval-extinction (or post-retrieval extinction), has also been found to be successful at preventing the return of fear in healthy fear conditioned humans (Schiller et al., Nature 463:49-53, 2010), and in the time since its discovery, there has been an explosion of research on the use of retrieval-extinction in fear memories in humans and other animals, some of which have found a long-term reduction in conditioned responding, and some who have not. These discrepant findings have raised concerns as to whether retrieval-extinction really results in updating of the original fear memory, or if it simply enhances extinction. We will first review the progress made on elucidating the cellular mechanisms underlying the fear attenuating effects of retrieval-extinction and how they differ from traditional extinction. Special attention will be paid to the molecular events necessary for retrieval-extinction to successfully occur and how these reconsolidated memories are represented in the brain. Next, we will examine the parameters that determine whether or not a memory will be updated via extinction during the reconsolidation window (also known as boundary conditions). These boundary conditions will also be discussed as possible explanations for discrepant findings of the retrieval-extinction effect. Then we will examine the factors that can determine whether an individual's fears will successfully be attenuated by retrieval-extinction. These individual differences include genetics, age, and psychopathology. Finally, we will discuss recent attempts to bring the retrieval-extinction paradigm from the bench to the bedside for the behavioral treatment of anxiety and trauma disorders.
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Affiliation(s)
- Marissa Raskin
- Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA
| | - Marie-H Monfils
- Department of Psychology, University of Texas at Austin, Austin, TX, USA.
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8
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Smits JAJ, Monfils MH, Otto MW, Telch MJ, Shumake J, Feinstein JS, Khalsa SS, Cobb AR, Parsons EM, Long LJ, McSpadden B, Johnson D, Greenberg A. CO 2 reactivity as a biomarker of exposure-based therapy non-response: study protocol. BMC Psychiatry 2022; 22:831. [PMID: 36575425 PMCID: PMC9793569 DOI: 10.1186/s12888-022-04478-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Exposure-based therapy is an effective first-line treatment for anxiety-, obsessive-compulsive, and trauma- and stressor-related disorders; however, many patients do not improve, resulting in prolonged suffering and poorly used resources. Basic research on fear extinction may inform the development of a biomarker for the selection of exposure-based therapy. Growing evidence links orexin system activity to deficits in fear extinction and we have demonstrated that reactivity to an inhaled carbon dioxide (CO2) challenge-a safe, affordable, and easy-to-implement procedure-can serve as a proxy for orexin system activity and predicts fear extinction deficits in rodents. Building upon this basic research, the goal for the proposed study is to validate CO2 reactivity as a biomarker of exposure-based therapy non-response. METHODS We will assess CO2 reactivity in 600 adults meeting criteria for one or more fear- or anxiety-related disorders prior to providing open exposure-based therapy. By incorporating CO2 reactivity into a multivariate model predicting treatment non-response that also includes reactivity to hyperventilation as well as a number of related predictor variables, we will establish the mechanistic specificity and the additive predictive utility of the potential CO2 reactivity biomarker. By developing models independently within two study sites (University of Texas at Austin and Boston University) and predicting the other site's data, we will validate that the results are likely to generalize to future clinical samples. DISCUSSION Representing a necessary stage in translating basic research, this investigation addresses an important public health issue by testing an accessible clinical assessment strategy that may lead to a more effective treatment selection (personalized medicine) for patients with anxiety- and fear-related disorders, and enhanced understanding of the mechanisms governing exposure-based therapy. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT05467683 (20/07/2022).
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Affiliation(s)
- Jasper A. J. Smits
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - Marie-H. Monfils
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - Michael W. Otto
- grid.189504.10000 0004 1936 7558Department of Psychological and Brain Sciences, Boston University, 900 Commonwealth Avenue, Floor 2, Boston, MA 02215 USA
| | - Michael J. Telch
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - Jason Shumake
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - Justin S. Feinstein
- grid.417423.70000 0004 0512 88633The Laureate Institute for Brain Research, 6655 South Yale Ave., Tulsa, Oklahoma 74136 USA
| | - Sahib S. Khalsa
- grid.417423.70000 0004 0512 88633The Laureate Institute for Brain Research, 6655 South Yale Ave., Tulsa, Oklahoma 74136 USA
| | - Adam R. Cobb
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA ,grid.259828.c0000 0001 2189 3475Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina and Ralph H. Johnson VAHCS, 67 President Street MSC 862, Charleston, SC 29425 USA
| | - E. Marie Parsons
- grid.189504.10000 0004 1936 7558Department of Psychological and Brain Sciences, Boston University, 900 Commonwealth Avenue, Floor 2, Boston, MA 02215 USA
| | - Laura J. Long
- grid.189504.10000 0004 1936 7558Department of Psychological and Brain Sciences, Boston University, 900 Commonwealth Avenue, Floor 2, Boston, MA 02215 USA
| | - Bryan McSpadden
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - David Johnson
- grid.89336.370000 0004 1936 9924Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, 1 University Station, Austin, TX 78712 USA
| | - Alma Greenberg
- grid.189504.10000 0004 1936 7558Department of Psychological and Brain Sciences, Boston University, 900 Commonwealth Avenue, Floor 2, Boston, MA 02215 USA
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9
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Pedraza LK, Sierra RO, de Oliveira Alvares L. Systems consolidation and fear memory generalisation as a potential target for trauma-related disorders. World J Biol Psychiatry 2022; 23:653-665. [PMID: 35001808 DOI: 10.1080/15622975.2022.2027010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fear memory generalisation is a central hallmark in the broad range of anxiety and trauma-related disorders. Recent findings suggest that fear generalisation is closely related to hippocampal dependency during retrieval. In this review, we describe the current understanding about memory generalisation and its potential influence in fear attenuation through pharmacological and behavioural interventions. In light of systems consolidation framework, we propose that keeping memory precision could be a key step to enhance therapeutic outcomes.
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Affiliation(s)
- Lizeth K Pedraza
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, 91.501-970, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Department of Physiology, University of Szeged, Szeged, Hungary
| | - Rodrigo O Sierra
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, 91.501-970, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Department of Physiology, University of Szeged, Szeged, Hungary
| | - Lucas de Oliveira Alvares
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, 91.501-970, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Graduate Program in Neuroscience, Institute of Health Sciences, Porto Alegre, Brazil
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10
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The elegant complexity of fear in non-human animals. Emerg Top Life Sci 2022; 6:445-455. [PMID: 36069657 PMCID: PMC9788375 DOI: 10.1042/etls20220001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 02/07/2023]
Abstract
Activation of the fear system is adaptive, and protects individuals from impending harm; yet, exacerbation of the fear system is at the source of anxiety-related disorders. Here, we briefly review the 'why' and 'how' of fear, with an emphasis on models that encapsulate the elegant complexity of rodents' behavioral responding in the face of impending harm, and its relevance to developing treatment interventions.
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11
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Ten-Blanco M, Flores Á, Pereda-Pérez I, Piscitelli F, Izquierdo-Luengo C, Cristino L, Romero J, Hillard CJ, Maldonado R, Di Marzo V, Berrendero F. Amygdalar CB2 cannabinoid receptor mediates fear extinction deficits promoted by orexin-A/hypocretin-1. Biomed Pharmacother 2022; 149:112925. [PMID: 35477218 DOI: 10.1016/j.biopha.2022.112925] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/25/2022] [Accepted: 04/04/2022] [Indexed: 11/02/2022] Open
Abstract
Anxiety and stress disorders are often characterized by an inability to extinguish learned fear responses. Orexins/hypocretins are involved in the modulation of aversive memories, and dysregulation of this system may contribute to the aetiology of anxiety disorders characterized by pathological fear. The mechanisms by which orexins regulate fear are unknown. Here we investigated the role of the endogenous cannabinoid system in the impaired fear extinction induced by orexin-A (OXA) in male mice. The selective inhibitor of 2-arachidonoylglycerol (2-AG) biosynthesis O7460 abolished the fear extinction deficits induced by OXA. Accordingly, increased 2-AG levels were observed in the amygdala and hippocampus of mice treated with OXA that do not extinguish fear, suggesting that high levels of this endocannabinoid are related to poor extinction. Impairment of fear extinction induced by OXA was associated with increased expression of CB2 cannabinoid receptor (CB2R) in microglial cells of the basolateral amygdala. Consistently, the intra-amygdala infusion of the CB2R antagonist AM630 completely blocked the impaired extinction promoted by OXA. Microglial and CB2R expression depletion in the amygdala with PLX5622 chow also prevented these extinction deficits. These results show that overactivation of the orexin system leads to impaired fear extinction through 2-AG and amygdalar CB2R. This novel mechanism could be of relevance for the development of novel potential approaches to treat diseases associated with inappropriate retention of fear, such as post-traumatic stress disorder, panic anxiety and phobias.
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Affiliation(s)
- Marc Ten-Blanco
- Instituto de Investigaciones Biosanitarias, Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - África Flores
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB, 08003 Barcelona, Spain
| | - Inmaculada Pereda-Pérez
- Instituto de Investigaciones Biosanitarias, Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy
| | - Cristina Izquierdo-Luengo
- Instituto de Investigaciones Biosanitarias, Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy
| | - Julián Romero
- Instituto de Investigaciones Biosanitarias, Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Cecilia J Hillard
- Department of Pharmacology and Toxicology and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB, 08003 Barcelona, Spain
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy; Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Faculty of Medicine and Faculty of Agriculture and Food Sciences, Hearth and Lung Research Institute (IUCPQ), Institute of Nutrition and Functional Foods (INAF) and NUTRISS Center, Université Laval, Quebec City, Canada
| | - Fernando Berrendero
- Instituto de Investigaciones Biosanitarias, Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain.
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12
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Appetitive Behavior in the Social Transmission of Food Preference Paradigm Predicts Activation of Orexin-A producing Neurons in a Sex-Dependent Manner. Neuroscience 2022; 481:30-46. [PMID: 34843892 DOI: 10.1016/j.neuroscience.2021.11.032] [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: 06/12/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 11/22/2022]
Abstract
Orexin-producing cells in the lateral hypothalamic area have been shown to be involved in a wide variety of behavioral and cognitive functions, including the recall of appetitive associations and a variety of social behaviors. Here, we investigated the role of orexin in the acquisition and recall of socially transmitted food preferences in the rat. Rats were euthanized following either acquisition, short-term recall, or long-term recall of a socially transmitted food preference and their brains were processed for orexin-A and c-Fos expression. We found that while there were no significant differences in c-Fos expression between control and experimental subjects at any of the tested timepoints, females displayed significantly more activity in both orexinergic and non-orexinergic cells in the lateral hypothalamus. In the infralimbic cortex, we found that social behavior was significantly predictive of c-Fos expression, with social behaviors related to olfactory exploration appearing to be particularly influential. We additionally found that appetitive behavior was significantly predictive of orexin-A activity in a sex-dependent matter, with the total amount eaten correlating negatively with orexin-A/c-Fos colocalization in male rats but not female rats. These findings suggest a potential sex-specific role for the orexin system in balancing the stimulation of feeding behavior with the sleep/wake cycle.
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13
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Tryon SC, Sakamoto IM, Kellis DM, Kaigler KF, Wilson MA. Individual Differences in Conditioned Fear and Extinction in Female Rats. Front Behav Neurosci 2021; 15:740313. [PMID: 34489657 PMCID: PMC8418198 DOI: 10.3389/fnbeh.2021.740313] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 07/29/2021] [Indexed: 11/13/2022] Open
Abstract
The inability to extinguish a traumatic memory is a key aspect of post-traumatic stress disorder (PTSD). While PTSD affects 10–20% of individuals who experience a trauma, women are particularly susceptible to developing the disorder. Despite this notable female vulnerability, few studies have investigated this particular resistance to fear extinction observed in females. Similar to humans, rodent models of Pavlovian fear learning and extinction show a wide range of individual differences in fear learning and extinction, although female rodents are considerably understudied. Therefore, the present study examined individual differences in fear responses, including freezing behavior and ultrasonic vocalizations (USVs), of female Long–Evans rats during acquisition of fear conditioning and cued fear extinction. Similar to prior studies in males, female rats displayed individual variation in freezing during cued fear extinction and were divided into extinction competent (EC) and extinction resistant (ER) phenotypes. Differences in freezing between ER and EC females were accompanied by shifts in rearing during extinction, but no darting was seen in any trial. Freezing behavior during fear learning did not differ between the EC and ER females. Vocalizations emitted in the 22 and 50 kHz ranges during fear learning and extinction were also examined. Unlike vocalizations seen in previous studies in males, very few 22 kHz distress vocalizations were emitted by female rats during fear acquisition and extinction, with no difference between ER and EC groups. Interestingly, all female rats produced significant levels of 50 kHz USVs, and EC females emitted significantly more 50 kHz USVs than ER rats. This difference in 50 kHz USVs was most apparent during initial exposure to the testing environment. These results suggest that like males, female rodents show individual differences in both freezing and USVs during fear extinction, although females appear to vocalize more in the 50 kHz range, especially during initial periods of exposure to the testing environment, and emit very few of the 22 kHz distress calls that are typically observed in males during fear learning or extinction paradigms. Overall, these findings show that female rodents display fear behavior repertoires divergent from males.
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Affiliation(s)
- Sarah C Tryon
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Iris M Sakamoto
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Devin M Kellis
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Kris F Kaigler
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Marlene A Wilson
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States.,Columbia VA Health Care System, Columbia, SC, United States
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14
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Kellis DM, Kaigler KF, Witherspoon E, Fadel JR, Wilson MA. Cholinergic neurotransmission in the basolateral amygdala during cued fear extinction. Neurobiol Stress 2020; 13:100279. [PMID: 33344731 PMCID: PMC7739185 DOI: 10.1016/j.ynstr.2020.100279] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 01/06/2023] Open
Abstract
Cholinergic neuromodulation plays an important role in numerous cognitive functions including regulating arousal and attention, as well as associative learning and extinction processes. Further, studies demonstrate that cholinergic inputs from the basal forebrain cholinergic system influence physiological responses in the basolateral amygdala (BLA) as well as fear extinction processes. Since rodent models display individual differences in conditioned fear and extinction responses, this study investigated if cholinergic transmission in the BLA during fear extinction could contribute to differences between extinction resistant and extinction competent phenotypes in outbred Long-Evans male rats. Experiment 1 used in vivo microdialysis to test the hypothesis that acetylcholine (ACH) efflux in the BLA would increase with presentation of an auditory conditioned stimulus (CS+) during extinction learning. Acetylcholine efflux was compared in rats exposed to the CS+, a CS- (the tone never paired with a footshock), or to a context shift alone (without CS+ tone presentation). Consistent with acetylcholine's role in attention and arousal, ACH efflux in the BLA was increased in all three groups (CS+, CS-, Shift Alone) by the initial context shift into the extinction learning chamber, but returned more rapidly to baseline levels in the Shift Alone group (no CS+). In contrast, in the group exposed to the CS+, ACH efflux in the BLA remained elevated during continued presentation of conditioned cues and returned to baseline more slowly, leading to an overall increase in ACH efflux compared with the Shift Alone group. Based on the very dense staining in the BLA for acetylcholinesterase (ACHE), Experiment 2 examined if individual differences in fear extinction were associated with differences in cholinesterase enzyme activity (CHE) in the BLA and/or plasma with a separate cohort of animals. Cholinesterase activity (post-testing) in both the BLA and plasma was higher in extinction competent rats versus rats resistant to extinction learning. There was also a significant negative correlation between BLA CHE activity and freezing during extinction learning. Taken together, our results support a role for ACH efflux in the BLA during cued fear extinction that may be modulated by individual differences in ACHE activity, and are associated with behavioral responses during fear extinction. These findings implicate individual differences in cholinergic regulation in the susceptibility to disorders with dysregulation of extinction learning, such post-traumatic stress disorder (PTSD) in humans. Basolateral amygdala acetylcholine efflux is increased during extinction learning. Acetylcholine efflux also increased transiently in amygdala during a context shift. Acetylcholinesterase activity in amygdala differed between extinction phenotypes. Amygdala cholinergic regulation contributes to variations in extinction learning.
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Affiliation(s)
- Devin M. Kellis
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, United States
| | - Kris Ford Kaigler
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, United States
| | - Eric Witherspoon
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, United States
| | - Jim R. Fadel
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, United States
| | - Marlene A. Wilson
- Columbia VA Health Care System, Columbia, SC, 29209, United States
- Corresponding author. Dept. Pharmacology, Physiology, & Neuroscience, Bldg 1 D26, University of South Carolina School of Medicine, Columbia, SC, 29208.
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15
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Abstract
The aim of this review is to summarize evidence regarding rat emotional experiences during carbon dioxide (CO2) exposure. The studies reviewed show that CO2 exposure is aversive to rats, and that rats respond to CO2 exposure with active and passive defense behaviors. Plasma corticosterone and bradycardia increased in rats exposed to CO2. As with anxiogenic drugs, responses to CO2 are counteracted by the administration of anxiolytics, SRIs, and SSRI's. Human studies reviewed indicate that, when inhaling CO2, humans experience feelings of anxiety fear and panic, and that administration of benzodiazepines, serotonin precursors, and SSRIs ameliorate these feelings. In vivo and in vitro rat studies reviewed show that brain regions, ion channels, and neurotransmitters involved in negative emotional responses are activated by hypercapnia and acidosis associated with CO2 exposure. On the basis of the behavioral, physiological, and neurobiological evidence reviewed, we conclude that CO2 elicits negative emotions in rats.
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16
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High Behavioral Sensitivity to Carbon Dioxide Associates with Enhanced Fear Memory and Altered Forebrain Neuronal Activation. Neuroscience 2020; 429:92-105. [PMID: 31930959 DOI: 10.1016/j.neuroscience.2019.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/13/2019] [Accepted: 12/08/2019] [Indexed: 01/06/2023]
Abstract
There is considerable interest in pre-trauma individual differences that may contribute to increased risk for developing post-traumatic stress disorder (PTSD). Identification of underlying vulnerability factors that predict differential responses to traumatic experiences is important. Recently, the relevance of homeostatic perturbations in shaping long-term behavior has been recognized. Sensitivity to CO2 inhalation, a homeostatic threat to survival, was shown to associate with the later development of PTSD symptoms in veterans. Here, we investigated whether behavioral sensitivity to CO2 associates with PTSD-relevant behaviors and alters forebrain fear circuitry in mice. Mice were exposed to 5% CO2 or air inhalation and tested one week later on acoustic startle and footshock contextual fear conditioning, extinction and reinstatement. CO2 inhalation evoked heterogenous freezing behaviors (high freezing CO2-H and low freezing CO2-L) that significantly associated with fear conditioning and extinction behaviors. CO2-H mice elicited potentiated conditioned fear and delayed extinction while behavioral responses in CO2-L mice were similar to the air group. Persistent neuronal activation marker ΔFosB immunostaining revealed altered regional neuronal activation within the hippocampus, amygdala and medial pre-frontal cortex that correlated with conditioned fear and extinction. Inter-regional co-activation mapping revealed disruptions in the coordinated activity of hippocampal dentate-amygdala-infralimbic regions and infralimbic-prelimbic associations in CO2-H mice that may explain their enhanced fear phenotype. In conclusion, our data support an association of behavioral sensitivity to interoceptive threats such as CO2 with altered fear responding to exteroceptive threats and suggest that "CO2-sensitive" individuals may be susceptible to developing PTSD.
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17
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Kuijer EJ, Ferragud A, Milton AL. Retrieval-Extinction and Relapse Prevention: Rewriting Maladaptive Drug Memories? Front Behav Neurosci 2020; 14:23. [PMID: 32153373 PMCID: PMC7044236 DOI: 10.3389/fnbeh.2020.00023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/03/2020] [Indexed: 12/24/2022] Open
Abstract
Addicted individuals are highly susceptible to relapse when exposed to drug-associated conditioned stimuli (CSs; "drug cues") even after extensive periods of abstinence. Until recently, these maladaptive emotional drug memories were believed to be permanent and resistant to change. The rediscovery of the phenomenon of memory reconsolidation-by which retrieval of the memory can, under certain conditions, destabilize the previously stable memory before it restabilizes in its new, updated form-has led to the hypothesis that it may be possible to disrupt the strong maladaptive drug-memories that trigger a relapse. Furthermore, recent work has suggested that extinction training "within the reconsolidation window" may lead to a long-term reduction in relapse without the requirement for pharmacological amnestic agents. However, this so-called "retrieval-extinction" effect has been inconsistently observed in the literature, leading some to speculate that rather than reflecting memory updating, it may be the product of facilitation of extinction. In this mini review article, we will focus on factors that might be responsible for the retrieval-extinction effects on preventing drug-seeking relapse and how inter-individual differences may influence this therapeutically promising effect. A better understanding of the psychological and neurobiological mechanisms underpinning the "retrieval-extinction" paradigm, and individual differences in boundary conditions, should provide insights with the potential to optimize the translation of "retrieval-extinction" to clinical populations.
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Affiliation(s)
- Eloise J. Kuijer
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- Leiden University Medical Centre, Leiden University, Leiden, Netherlands
| | - Antonio Ferragud
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
| | - Amy L. Milton
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
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18
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Améndola L, Ratuski A, Weary DM. Variation in the onset of CO 2-induced anxiety in female Sprague Dawley rats. Sci Rep 2019; 9:19007. [PMID: 31831816 PMCID: PMC6908729 DOI: 10.1038/s41598-019-55493-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
Carbon dioxide (CO2) is commonly used to kill laboratory rats. Rats find CO2 aversive and aversion varies between individuals, indicating that rats vary in CO2 sensitivity. Healthy humans experience feelings of anxiety at concentrations similar to those avoided by rats, and these feelings are diminished by the administration of benzodiazepines. Our aim was to assess the effects of the benzodiazepine midazolam on individual thresholds of rat aversion to CO2. Six female Sprague Dawley rats were repeatedly exposed to CO2 gradual-fill in approach-avoidance testing. The first three exposures were to a control-treatment followed by three exposures to midazolam (0.375 mg/kg). Within each treatment aversion to CO2 was not affected by exposure number; however, tolerance increased from an average of 10.7% CO2 avoided during control sessions, to 15.5% CO2 avoided when treated with midazolam. These results indicate that rats experience anxiety when exposed to CO2, and that variation in rat CO2 sensitivity is driven by individual differences in the onset of these feelings of anxiety. No rat tolerated CO2 concentrations required to induce loss of consciousness.
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Affiliation(s)
- Lucía Améndola
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Anna Ratuski
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Daniel M Weary
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada.
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Wilson MA, Liberzon I, Lindsey ML, Lokshina Y, Risbrough VB, Sah R, Wood SK, Williamson JB, Spinale FG. Common pathways and communication between the brain and heart: connecting post-traumatic stress disorder and heart failure. Stress 2019; 22:530-547. [PMID: 31161843 PMCID: PMC6690762 DOI: 10.1080/10253890.2019.1621283] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Psychiatric illnesses and cardiovascular disease (CVD) contribute to significant overall morbidity, mortality, and health care costs, and are predicted to reach epidemic proportions with the aging population. Within the Veterans Administration (VA) health care system, psychiatric illnesses such as post-traumatic stress disorder (PTSD) and CVD such as heart failure (HF), are leading causes of hospital admissions, prolonged hospital stays, and resource utilization. Numerous studies have demonstrated associations between PTSD symptoms and CVD endpoints, particularly in the Veteran population. Not only does PTSD increase the risk of HF, but this relationship is bi-directional. Accordingly, a VA-sponsored conference entitled "Cardiovascular Comorbidities in PTSD: The Brain-Heart Consortium" was convened to explore potential relationships and common biological pathways between PTSD and HF. The conference was framed around the hypothesis that specific common systems are dysregulated in both PTSD and HF, resulting in a synergistic acceleration and amplification of both disease processes. The conference was not intended to identify all independent pathways that give rise to PTSD and HF, but rather identify shared systems, pathways, and biological mediators that would be modifiable in both disease processes. The results from this conference identified specific endocrine, autonomic, immune, structural, genetic, and physiological changes that may contribute to shared PTSD-CVD pathophysiology and could represent unique opportunities to develop therapies for both PTSD and HF. Some recommendations from the group for future research opportunities are provided.
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Affiliation(s)
- Marlene A. Wilson
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine and Research Service, Columbia VA Health Care System, Columbia SC
- Corresponding author information: Marlene A. Wilson, Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia SC 29208, Research Service, Columbia VA Health Care System, Columbia SC 29209, ; 803-216-3507
| | - Israel Liberzon
- Department of Psychiatry, Texas A&M College of Medicine, Bryan, TX
| | - Merry L. Lindsey
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, and Research Service, Omaha VA Medical Center, Omaha NE
| | - Yana Lokshina
- Department of Psychiatry, Texas A&M College of Medicine, Bryan, TX
| | - Victoria B. Risbrough
- VA Center of Excellence for Stress and Mental Health, La Jolla CA, Dept. of Psychiatry, University of California San Diego
| | - Renu Sah
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Susan K. Wood
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine and Research Service, Columbia VA Health Care System, Columbia SC
| | - John B. Williamson
- Department of Neurology, University of Florida College of Medicine, Gainesville FL
| | - Francis G. Spinale
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine and Research Service, Columbia VA Health Care System., Columbia SC
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20
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Affiliation(s)
- Amy L Milton
- Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB, UK.
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
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