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Eyraud N, Bloch S, Brizard B, Pena L, Tharsis A, Surget A, El-Hage W, Belzung C. Influence of Stress Severity on Contextual Fear Extinction and Avoidance in a Posttraumatic-like Mouse Model. Brain Sci 2024; 14:311. [PMID: 38671963 PMCID: PMC11048507 DOI: 10.3390/brainsci14040311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/18/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024] Open
Abstract
Posttraumatic stress disorder (PTSD) is a widespread fear-related psychiatric affection associated with fear extinction impairments and important avoidance behaviors. Trauma-related exposure therapy is the current first-hand treatment for PTSD, yet it needs to be improved to shorten the time necessary to reach remission and increase responsiveness. Additional studies to decipher the neurobiological bases of extinction and effects on PTSD-like symptoms could therefore be of use. However, a PTSD-like animal model exhibiting pronounced PTSD-related phenotypes even after an extinction training directly linked to the fearful event is necessary. Thus, using a contextual fear conditioning model of PTSD, we increased the severity of stress during conditioning to search for effects on extinction acquisition and on pre- and post-extinction behaviors. During conditioning, mice received either two or four electrical shocks while a control group was constituted of mice only exposed to the context. Stressed mice exhibited important fear generalization, high fear reaction to the context and selective avoidance of a contextual reminder even after the extinction protocol. Increasing the number of footshocks did not induce major changes on these behaviors.
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Affiliation(s)
- Noémie Eyraud
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Solal Bloch
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Bruno Brizard
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Laurane Pena
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Antoine Tharsis
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Alexandre Surget
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
| | - Wissam El-Hage
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
- Pôle de Psychiatrie et d’Addictologie, Centre Hospitalier Régional Universitaire de Tours, 37000 Tours, France
| | - Catherine Belzung
- Institut National de la Santé et de la Recherche Médicale (INSERM), Imaging Brain & Neuropsychiatry iBraiN U1253, Université de Tours, 37032 Tours, France
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Shields GS, Fassett-Carman A, Gray ZJ, Gonzales JE, Snyder HR, Slavich GM. Why is subjective stress severity a stronger predictor of health than stressor exposure? A preregistered two-study test of two hypotheses. Stress Health 2023; 39:87-102. [PMID: 35599238 PMCID: PMC10243213 DOI: 10.1002/smi.3165] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 04/19/2022] [Accepted: 05/12/2022] [Indexed: 02/07/2023]
Abstract
Subjective stress severity appraisals have consistently emerged as better predictors of poor health than stressor exposure, but the reason for this is unclear. Subjective stress may better predict poor health for one of at least two reasons. First, because stressor exposure measures consider all stressors as equal, stress severity measures-which "weight" stressors by self-reported severity-might better predict poor health simply by not treating all stressors as being equally impactful. Second, subjective stress appraisals may index important individual differences in stress vulnerability. We tested these two possibilities in this preregistered, two-study manuscript. Across these two different studies, subjective stress severity was a better predictor of poor health than independently weighted stress severity or stressor exposure. These results demonstrate that, beyond weighting of stressful experiences, subjective stress severity indexes health-relevant individual differences. Moreover, the results suggest that subjective stress severity may be the preferred stress summary metric even when derived from imprecise stress assessment instruments.
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Affiliation(s)
| | | | - Zach J. Gray
- Department of Psychological Science, University of Arkansas
| | - Joseph E. Gonzales
- Department of Psychology and Center for Women and Work, University of Massachusetts Lowell
| | - Hannah R. Snyder
- Department of Psychology and Neuroscience Program, Brandeis University
| | - George M. Slavich
- Cousins Center for Psychoneuroimmunology and Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles
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Rieksta J, Li T, Davie‐Martin CL, Aeppli LCB, Høye TT, Rinnan R. Volatile responses of dwarf birch to mimicked insect herbivory and experimental warming at two elevations in Greenlandic tundra. Plant Environ Interact 2023; 4:23-35. [PMID: 37284597 PMCID: PMC10168049 DOI: 10.1002/pei3.10100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 06/08/2023]
Abstract
Plants release a complex blend of volatile organic compounds (VOCs) in response to stressors. VOC emissions vary between contrasting environments and increase with insect herbivory and rising temperatures. However, the joint effects of herbivory and warming on plant VOC emissions are understudied, particularly in high latitudes, which are warming fast and facing increasing herbivore pressure. We assessed the individual and combined effects of chemically mimicked insect herbivory, warming, and elevation on dwarf birch (Betula glandulosa) VOC emissions in high-latitude tundra ecosystems in Narsarsuaq, South Greenland. We hypothesized that VOC emissions and compositions would respond synergistically to warming and herbivory, with the magnitude differing between elevations. Warming increased emissions of green leaf volatiles (GLVs) and isoprene. Herbivory increased the homoterpene, (E)-4,8-dimethyl-1,3,7-nonatriene, emissions, and the response was stronger at high elevation. Warming and herbivory had synergistic effects on GLV emissions. Dwarf birch emitted VOCs at similar rates at both elevations, but the VOC blends differed between elevations. Several herbivory-associated VOC groups did not respond to herbivory. Harsher abiotic conditions at high elevations might not limit VOC emissions from dwarf birch, and high-elevation plants might be better at herbivory defense than assumed. The complexity of VOC responses to experimental warming, elevation, and herbivory are challenging our understanding and predictions of future VOC emissions from dwarf birch-dominated ecosystems.
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Affiliation(s)
- Jolanta Rieksta
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
| | - Tao Li
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research StationKey Laboratory for Bio‐resource and Eco‐environment of Ministry of EducationCollege of Life SciencesSichuan UniversityChengduChina
| | - Cleo L. Davie‐Martin
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
| | - Laurids Christian Brogaard Aeppli
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
| | - Toke Thomas Høye
- Department of Bioscience and Arctic Research CentreAarhus UniversityAarhus CDenmark
| | - Riikka Rinnan
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
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Rieksta J, Li T, Junker RR, Jepsen JU, Ryde I, Rinnan R. Insect Herbivory Strongly Modifies Mountain Birch Volatile Emissions. Front Plant Sci 2020; 11:558979. [PMID: 33193483 PMCID: PMC7652793 DOI: 10.3389/fpls.2020.558979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/07/2020] [Indexed: 05/06/2023]
Abstract
Insect herbivory is known to augment emissions of biogenic volatile organic compounds (BVOCs). Yet few studies have quantified BVOC responses to insect herbivory in natural populations in pan-Arctic regions. Here, we assess how quantitative and qualitative BVOC emissions change with increasing herbivore feeding intensity in the Subarctic mountain birch (Betula pubescens var pumila (L.)) forest. We conducted three field experiments in which we manipulated the larval density of geometrid moths (Operophtera brumata and Epirrita autumnata), on branches of mountain birch and measured BVOC emissions using the branch enclosure method and gas chromatography-mass spectrometry. Our study showed that herbivory significantly increased BVOC emissions from the branches damaged by larvae. BVOC emissions increased due to insect herbivory at relatively low larvae densities, causing up to 10% of leaf area loss. Insect herbivory also changed the blend composition of BVOCs, with damaged plants producing less intercorrelated BVOC blends than undamaged ones. Our results provide a quantitative understanding of the relationship between the severity of insect herbivore damage and emissions of BVOCs at larvae densities corresponding to background herbivory levels in the Subarctic mountain birch. The results have important and practical implications for modeling induced and constitutive BVOC emissions and their feedbacks to atmospheric chemistry.
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Affiliation(s)
- Jolanta Rieksta
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Tao Li
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Tao Li,
| | - Robert R. Junker
- Evolutionary Ecology of Plants, Department of Biology, Philipps-University Marburg, Marburg, Germany
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Jane U. Jepsen
- Norwegian Institute for Nature Research, Fram Centre, Tromsø, Norway
| | - Ingvild Ryde
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Section for Plant Biochemistry, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Riikka Rinnan
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
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Turan S, Kask K, Kanagendran A, Li S, Anni R, Talts E, Rasulov B, Kännaste A, Niinemets Ü. Lethal heat stress-dependent volatile emissions from tobacco leaves: what happens beyond the thermal edge? J Exp Bot 2019; 70:5017-5030. [PMID: 31289830 PMCID: PMC6850906 DOI: 10.1093/jxb/erz255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/20/2019] [Indexed: 05/10/2023]
Abstract
Natural vegetation is predicted to suffer from extreme heat events as a result of global warming. In this study, we focused on the immediate response to heat stress. Photosynthesis and volatile emissions were measured in the leaves of tobacco (Nicotiana tabacum cv. Wisconsin 38) after exposure to heat shock treatments between 46 °C and 55 °C. Exposure to 46 °C decreased photosynthetic carbon assimilation rates (A) by >3-fold. Complete inhibition of A was observed at 49 °C, together with a simultaneous decrease in the maximum quantum efficiency of PSII, measured as the Fv/Fm ratio. A large increase in volatile emissions was observed at 52 °C. Heat stress resulted in only minor effects on the emission of monoterpenes, but volatiles associated with membrane damage such as propanal and (E)-2-hexenal+(Z)-3-hexenol were greatly increased. Heat induced changes in the levels of methanol and 2-ethylfuran that are indicative of modification of cell walls. In addition, the oxidation of metabolites in the volatile profiles was strongly enhanced, suggesting the acceleration of oxidative processes at high temperatures that are beyond the thermal tolerance limit.
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Affiliation(s)
- Satpal Turan
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Kaia Kask
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Arooran Kanagendran
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Shuai Li
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Rinaldo Anni
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Eero Talts
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Bahtijor Rasulov
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Astrid Kännaste
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
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Fassett-Carman A, Hankin BL, Snyder HR. Appraisals of dependent stressor controllability and severity are associated with depression and anxiety symptoms in youth. Anxiety Stress Coping 2018; 32:32-49. [PMID: 30303017 DOI: 10.1080/10615806.2018.1532504] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND OBJECTIVES Stress is well established as a strong risk factor for internalizing psychopathology. Learned helplessness research demonstrates that perceived controllability of stressors affects internalizing symptoms. Furthermore, subjective perceived stress is associated with psychopathology. However, most recent research has focused on measuring the frequency and expert-rated severity of stressful life events despite evidence for the importance of stress perceptions. The present study brings together past and current literatures to investigate the importance of perceived severity and controllability of recent life events in the association between stressors and internalizing symptoms. DESIGN AND METHODS We used a revised version of the Adolescent Life Events Questionnaire (ALEQ) that asked participants (ages 13-22, N = 328) to rate the frequency of 65 stressful events typical to youth, as well as the perceived stressfulness and control they felt over each event. Events were categorized prior to analysis as dependent (self-generated), independent (fateful) or neither. RESULTS Controllability and severity appraisals were associated with depression and anxiety symptoms, controlling for stressor frequency (which also predicted symptoms), for dependent but not independent stressors. CONCLUSIONS These results highlight the importance of controllability and severity appraisals as potential risk factors for internalizing disorders, exposing a potential target for therapy.
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Affiliation(s)
| | - Benjamin L Hankin
- b Department of Psychology , University of Illinois at Urbana-Champaign , Champaign , IL , USA
| | - Hannah R Snyder
- c Department of Psychology , Brandeis University , Waltham , MA , USA
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Qian XL, Yarnal CM, Almeida DM. Is leisure time availability associated with more or less severe daily stressors? An examination using eight-day diary data. Leis Sci 2014; 36:35-51. [PMID: 24563564 PMCID: PMC3927970 DOI: 10.1080/01490400.2014.860782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/28/2013] [Indexed: 06/03/2023]
Abstract
The stress suppressing model proposes that sufficient resources reduce stress. The stress exposure model suggests that certain factors expose individuals to more stress. The current study tested these two models by assessing the within-person lagging effect of leisure time on perceived severity of daily stressors. Analyzing eight-day diary data (N=2,022), we found that having more leisure time than usual on a day reduced perceived severity of daily stressors the next day and that the decrease in severity became larger with further increase in leisure time. Additionally, the effect is much stronger among busy individuals who usually had little leisure time. The findings demonstrated an accelerated suppressing effect that differed between-person, and the lagging effect affords stronger implication for causality than correlational analysis.
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Affiliation(s)
| | - Careen M Yarnal
- Department of Recreation, Park, and Tourism Management The Pennsylvania State University
| | - David M Almeida
- Department of Human Development and Family Studies The Pennsylvania State University
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