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Nachtigall EG, de C Myskiw J, Izquierdo I, Furini CRG. Cellular mechanisms of contextual fear memory reconsolidation: Role of hippocampal SFKs, TrkB receptors and GluN2B-containing NMDA receptors. Psychopharmacology (Berl) 2024; 241:61-73. [PMID: 37700085 DOI: 10.1007/s00213-023-06463-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 08/31/2023] [Indexed: 09/14/2023]
Abstract
Memories are stored into long-term representations through a process that depends on protein synthesis. However, a consolidated memory is not static and inflexible and can be reactivated under certain circumstances, the retrieval is able to reactivate memories and destabilize them engaging a process of restabilization known as reconsolidation. Although the molecular mechanisms that mediate fear memory reconsolidation are not entirely known, so here we investigated the molecular mechanisms in the hippocampus involved in contextual fear conditioning memory (CFC) reconsolidation in male Wistar rats. We demonstrated that the blockade of Src family kinases (SFKs), GluN2B-containing NMDA receptors and TrkB receptors (TrkBR) in the CA1 region of the hippocampus immediately after the reactivation session impaired contextual fear memory reconsolidation. These impairments were blocked by the neurotrophin BDNF and the NMDAR agonist, D-Serine. Considering that the study of the link between synaptic proteins is crucial for understanding memory processes, targeting the reconsolidation process may provide new ways of disrupting maladaptive memories, such as those seen in post-traumatic stress disorder. Here we provide new insights into the cellular mechanisms involved in contextual fear memory reconsolidation, demonstrating that SFKs, GluN2B-containing NMDAR, and TrkBR are necessary for the reconsolidation process. Our findings suggest a link between BDNF and SFKs and GluN2B-containing NMDAR as well as a link between NMDAR and SFKs and TrkBR in fear memory reconsolidation. These preliminary pharmacological findings provide new evidence of the mechanisms involved in the reconsolidation of fear memory and have the potential to contribute to the development of treatments for psychiatric disorders involving maladaptive memories.
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Affiliation(s)
- Eduarda G Nachtigall
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, Porto Alegre, RS, 90610-000, Brazil
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2nd floor - HSL, Porto Alegre, RS, 90610-000, Brazil
| | - Jociane de C Myskiw
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2nd floor - HSL, Porto Alegre, RS, 90610-000, Brazil
| | - Ivan Izquierdo
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2nd floor - HSL, Porto Alegre, RS, 90610-000, Brazil
| | - Cristiane R G Furini
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, Porto Alegre, RS, 90610-000, Brazil.
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2nd floor - HSL, Porto Alegre, RS, 90610-000, Brazil.
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Mice deficient in synaptic protease neurotrypsin show impaired spaced long-term potentiation and blunted learning-induced modulation of dendritic spines. Cell Mol Life Sci 2023; 80:82. [PMID: 36871239 PMCID: PMC9986217 DOI: 10.1007/s00018-023-04720-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 01/21/2023] [Accepted: 02/06/2023] [Indexed: 03/06/2023]
Abstract
Neurotrypsin (NT) is a neuronal trypsin-like serine protease whose mutations cause severe mental retardation in humans. NT is activated in vitro by Hebbian-like conjunction of pre- and postsynaptic activities, which promotes the formation of dendritic filopodia via proteolytic cleavage of the proteoglycan agrin. Here, we investigated the functional importance of this mechanism for synaptic plasticity, learning, and extinction of memory. We report that juvenile neurotrypsin-deficient (NT-/-) mice exhibit impaired long-term potentiation induced by a spaced stimulation protocol designed to probe the generation of new filopodia and their conversion into functional synapses. Behaviorally, juvenile NT-/- mice show impaired contextual fear memory and have a sociability deficit. The latter persists in aged NT-/- mice, which, unlike juvenile mice, show normal recall but impaired extinction of contextual fear memories. Structurally, juvenile mutants exhibit reduced spine density in the CA1 region, fewer thin spines, and no modulation in the density of dendritic spines following fear conditioning and extinction in contrast to wild-type littermates. The head width of thin spines is reduced in both juvenile and aged NT-/- mice. In vivo delivery of adeno-associated virus expressing an NT-generated fragment of agrin, agrin-22, but not a shorter agrin-15, elevates the spine density in NT-/- mice. Moreover, agrin-22 co-aggregates with pre- and postsynaptic markers and increases the density and size of presynaptic boutons and presynaptic puncta, corroborating the view that agrin-22 supports the synaptic growth.
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Champarini LG, Herrera ML, Comas Mutis RG, Espejo PJ, Molina VA, Calfa GD, Hereñú CB. Effect of intra-BLA overexpression of IGF-1 on the expression of a contextual fear memory trace. Hippocampus 2022; 32:765-775. [PMID: 36000813 DOI: 10.1002/hipo.23465] [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: 11/05/2021] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/08/2022]
Abstract
Growth factors, such as insulin-like growth factor 1 (IGF-1), among others are known for their critical involvement in learning and memory processes. IGF-1 regulates cognitive functions, synapse density, neurotransmission, and adult neurogenesis and induces structural and synaptic plasticity-specific changes. Although IGF-1 has been suggested to participate in different memory processes, its role in memories associated with negative emotional experiences still remains to be elucidated. The principal aim of the present study was to test whether IGF-1 overexpression using adenoviral vectors in basolateral amygdala (BLA) influences both the expression and formation of contextual fear memory, as well as the hippocampal structural plasticity associated with such memory trace. We found that IGF-1 overexpression promotes the formation and expression of a specific contextual fear memory trace, and such effect persisted at least 7 days after recall. Moreover, the overexpression of this growth factor in BLA upregulates the activation of the ERK/MAPK pathway in this brain structure. In addition, intra-BLA IGF-1 overexpression causes dorsal hippocampus (DH) structural plasticity modifications promoting changes in the proportion of mature dendritic spines in the CA1 region, after a weak conditioning protocol. The present findings contribute to the knowledge underlying BLA-DH trace memory of fear and reveal important new insights into the neurobiology and neurochemistry of fear acquisition modulated by IGF-1 overexpression. The understanding of how IGF-1 modulates the formation of a fear contextual trace may pave the way for the development of novel therapeutic strategies focused on fear, anxiety, and trauma-related disorders.
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Affiliation(s)
- Leandro Gabriel Champarini
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Macarena Lorena Herrera
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Ramiro Gabriel Comas Mutis
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Pablo Javier Espejo
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Victor Alejandro Molina
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Gastón Diego Calfa
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
| | - Claudia Beatriz Hereñú
- Departamento de Farmacología, Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Cordoba, Argentina
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Comas Mutis R, Espejo PJ, Martijena ID, Molina VA, Calfa GD. Temporal dynamic of the hippocampal structural plasticity associated with the fear memory destabilization/reconsolidation process. Hippocampus 2021; 31:1080-1091. [PMID: 34190369 DOI: 10.1002/hipo.23374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/17/2021] [Accepted: 06/06/2021] [Indexed: 11/11/2022]
Abstract
Reconsolidation of a contextual fear memory is a protein synthesis-dependent process in which a previously destabilized memory returns to a stable state. This process has become the subject of many studies due to its importance in memory processing, maintenance and updating, and its potential role as a therapeutical target in fear memory disorders such as phobias and post-traumatic stress disorder. In this sense, understanding the underlying mechanisms of memory reconsolidation is paramount in developing potential treatments for such memory dysfunctions. In the present work, we studied the interaction between two key neural structures involved in the reconsolidation process: the basolateral amygdala complex of the amygdala (BLA) and the dorsal hippocampus (DH). Our results show changes in the structural plasticity of the CA1 region of the DH in the form of dendritic spines density changes associated with the destabilization/reconsolidation process. Furthermore, we demonstrate a modulatory role of BLA over such structural plasticity by infusing different drugs such as ifenprodil, a destabilization blocker, and propranolol, a reconsolidation disruptor, in this brain structure. Altogether our work shows a particular temporal dynamic in the CA1 region of DH that accompanies the destabilization/reconsolidation process and aims to provide new information on the underlying mechanisms of this process that potentially contributes for a better understanding of memory storage, maintenance, expression and updating, and its potential medical applications.
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Affiliation(s)
- Ramiro Comas Mutis
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Pablo Javier Espejo
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Irene Delia Martijena
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Victor Alejandro Molina
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Gastón Diego Calfa
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
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Nguyen AQ, Koeppen J, Woodruff S, Mina K, Figueroa Z, Ethell IM. Astrocytic Ephrin-B1 Controls Synapse Formation in the Hippocampus During Learning and Memory. Front Synaptic Neurosci 2020; 12:10. [PMID: 32256333 PMCID: PMC7092624 DOI: 10.3389/fnsyn.2020.00010] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/24/2020] [Indexed: 01/20/2023] Open
Abstract
Astrocytes play a fundamental role in synapse formation, pruning, and plasticity, which are associated with learning and memory. However, the role of astrocytes in learning and memory is still largely unknown. Our previous study showed that astrocyte-specific ephrin-B1 knock-out (KO) enhanced but ephrin-B1 overexpression (OE) in hippocampal astrocytes impaired contextual memory recall following fear conditioning. The goal of this study was to understand the mechanism by which astrocytic ephrin-B1 influences learning; specifically, learning-induced remodeling of synapses and dendritic spines in CA1 hippocampus using fear-conditioning paradigm. While we found a higher dendritic spine density and clustering on c-Fos-positive (+) neurons activated during contextual memory recall in both wild-type (WT) and KO mice, overall spine density and mEPSC amplitude were increased in CA1 neurons of KO compared to WT. In contrast, ephrin-B1 OE in hippocampal astrocytes impaired dendritic spine formation and clustering, specifically on c-Fos(+) neurons, coinciding with an overall decrease in vGlut1/PSD95 co-localization. Although astrocytic ephrin-B1 influenced learning-induced spine formation, the changes in astrocytic ephrin-B1 levels did not affect spine enlargement as no genotype differences in spine volume were observed between trained WT, KO, and OE groups. Our results suggest that a reduced formation of new spines rather than spine maturation in activated CA1 hippocampal neurons is most likely responsible for impaired contextual learning in OE mice due to abundantly high ephrin-B1 levels in astrocytes. The ability of astrocytic ephrin-B1 to negatively influence new spine formation during learning can potentially regulate new synapse formation at specific dendritic domains and underlie memory encoding.
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Affiliation(s)
- Amanda Q. Nguyen
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States
| | - Jordan Koeppen
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
- Cell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, Riverside, CA, United States
| | - Simone Woodruff
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
| | - Karen Mina
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
| | - Zoe Figueroa
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
| | - Iryna M. Ethell
- Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, United States
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States
- Cell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, Riverside, CA, United States
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De Luca SN, Soch A, Sominsky L, Nguyen TX, Bosakhar A, Spencer SJ. Glial remodeling enhances short-term memory performance in Wistar rats. J Neuroinflammation 2020; 17:52. [PMID: 32028971 PMCID: PMC7006153 DOI: 10.1186/s12974-020-1729-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/28/2020] [Indexed: 12/16/2022] Open
Abstract
Background Microglia play a key role in neuronal circuit and synaptic maturation in the developing brain. In the healthy adult, however, their role is less clear: microglial hyperactivation in adults can be detrimental to memory due to excessive synaptic pruning, yet learning and memory can also be impaired in the absence of these cells. In this study, we therefore aimed to determine how microglia contribute to short-term memory in healthy adults. Methods To this end, we developed a Cx3cr1-Dtr transgenic Wistar rat with a diphtheria toxin receptor (Dtr) gene inserted into the fractalkine receptor (Cx3cr1) promoter, expressed on microglia and monocytes. This model allows acute microglial and monocyte ablation upon application of diphtheria toxin, enabling us to directly assess microglia’s role in memory. Results Here, we show that short-term memory in the novel object and place recognition tasks is entirely unaffected by acute microglial ablation. However, when microglia repopulate the brain after depletion, learning and memory performance in these tasks is improved. This transitory memory enhancement is associated with an ameboid morphology in the newly repopulated microglial cells and increased astrocyte density that are linked with a higher density of mature hippocampal synaptic spines and differences in pre- and post-synaptic markers. Conclusions These data indicate that glia play a complex role in the healthy adult animal in supporting appropriate learning and memory and that subtle changes to the function of these cells may strategically enhance memory.
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Affiliation(s)
- Simone N De Luca
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Alita Soch
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Luba Sominsky
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Thai-Xinh Nguyen
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Abdulhameed Bosakhar
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia. .,ARC Centre of Excellence for Nanoscale Biophotonics, RMIT University, Melbourne, VIC, Australia.
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Cabral A, Fernandez G, Tolosa MJ, Rey Moggia Á, Calfa G, De Francesco PN, Perello M. Fasting induces remodeling of the orexigenic projections from the arcuate nucleus to the hypothalamic paraventricular nucleus, in a growth hormone secretagogue receptor-dependent manner. Mol Metab 2019; 32:69-84. [PMID: 32029231 PMCID: PMC7005150 DOI: 10.1016/j.molmet.2019.11.014] [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: 09/16/2019] [Revised: 11/14/2019] [Accepted: 11/20/2019] [Indexed: 02/06/2023] Open
Abstract
Objective Arcuate nucleus (ARC) neurons producing Agouti-related peptide (AgRP) and neuropeptide Y (NPY; ARCAgRP/NPY neurons) are activated under energy-deficit states. ARCAgRP/NPY neurons innervate the hypothalamic paraventricular nucleus (PVH), and ARC→PVH projections are recognized as key regulators of food intake. Plasma ghrelin levels increase under energy-deficit states and activate ARCAgRP/NPY neurons by acting on the growth hormone secretagogue receptor (GHSR). Here, we hypothesized that activation of ARCAgRP/NPY neurons in fasted mice would promote morphological remodeling of the ARCAgRP/NPY→PVH projections in a GHSR-dependent manner. Methods We performed 1) fluorescent immunohistochemistry, 2) imaging of green fluorescent protein (GFP) signal in NPY-GFP mice, and 3) DiI axonal labeling in brains of ad libitum fed or fasted mice with pharmacological or genetic blockage of the GHSR signaling and then estimated the density and strength of ARCAgRP/NPY→PVH fibers by assessing the mean fluorescence intensity, the absolute area with fluorescent signal, and the intensity of the fluorescent signal in the fluorescent area of the PVH. Results We found that 1) the density and strength of ARCAgRP/NPY fibers increase in the PVH of fasted mice, 2) the morphological remodeling of the ARCAgRP/NPY→PVH projections correlates with the activation of PVH neurons, and 3) PVH neurons are not activated in ARC-ablated mice. We also found that fasting-induced remodeling of ARCAgRP/NPY→PVH fibers and PVH activation are impaired in mice with pharmacological or genetic blockage of GHSR signaling. Conclusion This evidence shows that the connectivity between hypothalamic circuits controlling food intake can be remodeled in the adult brain, depending on the energy balance conditions, and that GHSR activity is a key regulator of this phenomenon. The density and strength of ARCAgRP/NPY→PVH fibers increase in fasted mice. Remodeling of ARCAgRP/NPY→PVH projections correlates with the activation of PVH neurons. GHSR signaling is required for fasting-induced ARCAgRP/NPY→PVH projection remodeling.
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Affiliation(s)
- Agustina Cabral
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Gimena Fernandez
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - María J Tolosa
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Ángeles Rey Moggia
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Gastón Calfa
- Instituto de Farmacología Experimental de Córdoba (IFEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Pablo N De Francesco
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina.
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Giachero M, Pavesi E, Calfa G, Motta SC, Canteras NS, Molina VA, Carobrez AP. Inactivation of the dorsolateral periaqueductal gray matter impairs the promoting influence of stress on fear memory during retrieval. Brain Struct Funct 2019; 224:3117-3132. [DOI: 10.1007/s00429-019-01956-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 09/03/2019] [Indexed: 10/26/2022]
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Pedraza LK, Sierra RO, Giachero M, Nunes-Souza W, Lotz FN, de Oliveira Alvares L. Chronic fluoxetine prevents fear memory generalization and enhances subsequent extinction by remodeling hippocampal dendritic spines and slowing down systems consolidation. Transl Psychiatry 2019; 9:53. [PMID: 30705259 PMCID: PMC6355903 DOI: 10.1038/s41398-019-0371-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 11/16/2018] [Accepted: 01/01/2019] [Indexed: 11/11/2022] Open
Abstract
Fear memory overgeneralization contributes to the genesis and persistence of anxiety disorders and is a central hallmark in the pathophysiology of post-traumatic stress disorder (PTSD). Recent findings suggest that fear generalization is closely related to hippocampal dependency during retrieval. The selective serotonin reuptake inhibitor (SSRI) fluoxetine has been used as a first-line treatment for PTSD; however, how it exerts its therapeutic effect remains a matter of debate. Here, using contextual fear conditioning in rats, we show that chronic fluoxetine treatment prevents fear generalization and enhances subsequent extinction. Moreover, fluoxetine treatment after extinction prevents spontaneous recovery. The mechanism through which fluoxetine affects generalization and extinction seems to be through the postponement of systems consolidation, thereby maintaining hippocampal involvement during retrieval. Such an effect relies on a remodeling of dendritic spines in the hippocampus, as well as the number of mature, mushroom-type spines promoted by fluoxetine treatment. In order to further investigate whether fear generalization is a potential predictor of extinction effectiveness, we categorized a large naive population according to their generalization rate. We found that discriminator rats showed a better extinction profile compared to generalizers, suggesting that the generalization rate predicts extinction effectiveness. Hence, we propose that the therapeutic strategy of choice should take into account the extension of memory generalization, in which therapies based on extinction could induce a better outcome in patients who present less fear overgeneralization. These results open new avenues for the development of interventions that prevent fear generalization by maintaining memory dependency of the hippocampus.
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Affiliation(s)
- Lizeth K. Pedraza
- Laboratório de Neurobiologia da Memória, Biosciences Institute, Porto Alegre, 91.501-970 Brazil ,0000 0001 2200 7498grid.8532.cGraduate Program in Neuroscience, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90.046-900 Brazil
| | - Rodrigo O. Sierra
- 0000 0001 2200 7498grid.8532.cGraduate Program in Neuroscience, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90.046-900 Brazil ,Laboratório de Psicobiologia e Neurocomputação, Biophysics Department, Biosciences Institute, Porto Alegre, 91.501-970 Brazil
| | - Marcelo Giachero
- 0000 0001 2188 7235grid.411237.2Department of Pharmacology, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Walquiria Nunes-Souza
- 0000 0001 2200 7498grid.8532.cGraduate Program in Neuroscience, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90.046-900 Brazil
| | - Fernanda N. Lotz
- Laboratório de Psicobiologia e Neurocomputação, Biophysics Department, Biosciences Institute, Porto Alegre, 91.501-970 Brazil
| | - Lucas de Oliveira Alvares
- Laboratório de Neurobiologia da Memória, Biosciences Institute, Porto Alegre, 91.501-970, Brazil. .,Graduate Program in Neuroscience, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90.046-900, Brazil.
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Arias-Cavieres A, More J, Vicente JM, Adasme T, Hidalgo J, Valdés JL, Humeres A, Valdés-Undurraga I, Sánchez G, Hidalgo C, Barrientos G. Triclosan Impairs Hippocampal Synaptic Plasticity and Spatial Memory in Male Rats. Front Mol Neurosci 2018; 11:429. [PMID: 30534053 PMCID: PMC6275195 DOI: 10.3389/fnmol.2018.00429] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/05/2018] [Indexed: 12/12/2022] Open
Abstract
Triclosan, a widely used industrial and household agent, is present as an antiseptic ingredient in numerous products of everyday use, such as toothpaste, cosmetics, kitchenware, and toys. Previous studies have shown that human brain and animal tissues contain triclosan, which has been found also as a contaminant of water and soil. Triclosan disrupts heart and skeletal muscle Ca2+ signaling, damages liver function, alters gut microbiota, causes colonic inflammation, and promotes apoptosis in cultured neocortical neurons and neural stem cells. Information, however, on the possible effects of triclosan on the function of the hippocampus, a key brain region for spatial learning and memory, is lacking. Here, we report that triclosan addition at low concentrations to hippocampal slices from male rats inhibited long-term potentiation but did not affect basal synaptic transmission or paired-pulse facilitation and modified the content or phosphorylation levels of synaptic plasticity-related proteins. Additionally, incubation of primary hippocampal cultures with triclosan prevented both the dendritic spine remodeling induced by brain-derived neurotrophic factor and the emergence of spontaneous oscillatory Ca2+ signals. Furthermore, intra-hippocampal injection of triclosan significantly disrupted rat navigation in the Oasis maze spatial memory task, an indication that triclosan impairs hippocampus-dependent spatial memory performance. Based on these combined results, we conclude that triclosan exerts highly damaging effects on hippocampal neuronal function in vitro and impairs spatial memory processes in vivo.
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Affiliation(s)
| | - Jamileth More
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | | | - Tatiana Adasme
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
- Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O’Higgins, Santiago, Chile
| | - Jorge Hidalgo
- Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - José Luis Valdés
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Alexis Humeres
- Department of Morphofunction, Faculty of Medicine, Universidad Diego Portales, Santiago, Chile
| | | | - Gina Sánchez
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
- Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- CEMC, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
- Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- CEMC, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Genaro Barrientos
- Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- CEMC, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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11
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Early Exposure to a High-Fat Diet Impacts on Hippocampal Plasticity: Implication of Microglia-Derived Exosome-like Extracellular Vesicles. Mol Neurobiol 2018; 56:5075-5094. [PMID: 30474797 DOI: 10.1007/s12035-018-1435-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/15/2018] [Indexed: 12/18/2022]
Abstract
Adolescence is a transitional period from childhood to adulthood characterized by puberty and brain maturation involving behavioral changes and environmental vulnerability. Diet is one of the factors affecting brain health, potentially leading to long-lasting effects. Hence, we studied the impact of early exposure (P21-60) to a high-fat diet (HFD) on mouse hippocampus, analyzing inflammation, adult neurogenesis, dendritic spine plasticity, and spatial memory. Glycemia and seric pro-inflammatory IL1β were higher in HFD mice without differences on body weight. In the HFD hippocampus, neuroinflammation was evidenced by Iba1+ cells reactivity together with a higher expression of TNFα and IL1β while the neurogenic capability in the dentate gyrus was strongly reduced. We found a predominance of immature Dil-labeled dendritic spines from CA1 neurons along with diminished levels of the scaffold protein Shank2, suggesting a defective connectivity. Moreover, the HFD group exhibited spatial memory alterations. To elucidate whether microglia could be mediating HFD-associated neuronal changes, the lipotoxic context was emulated by incubating primary microglia with palmitate, a saturated fatty acid present in HFD. Palmitate induced a pro-inflammatory profile as shown by secreted cytokine levels. The isolated exosome fraction from palmitate-stimulated microglia induced an immature dendritic spine phenotype in primary GFP+ hippocampal neurons, in line with the in vivo findings. These results provide novel data concerning microglia to neuron communication and highlight that fat excess during a short and early period of life could negatively impact on cognition and synaptic plasticity in a neuroinflammatory context, where microglia-derived exosomes could be implicated. Graphical Abstract ᅟ.
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12
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Stress influences the dynamics of hippocampal structural remodeling associated with fear memory extinction. Neurobiol Learn Mem 2018; 155:412-421. [DOI: 10.1016/j.nlm.2018.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 08/11/2018] [Accepted: 09/04/2018] [Indexed: 01/12/2023]
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13
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Jie F, Yin G, Yang W, Yang M, Gao S, Lv J, Li B. Stress in Regulation of GABA Amygdala System and Relevance to Neuropsychiatric Diseases. Front Neurosci 2018; 12:562. [PMID: 30154693 PMCID: PMC6103381 DOI: 10.3389/fnins.2018.00562] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 07/25/2018] [Indexed: 01/19/2023] Open
Abstract
The amygdala is an almond-shaped nucleus located deep and medially within the temporal lobe and is thought to play a crucial role in the regulation of emotional processes. GABAergic neurotransmission inhibits the amygdala and prevents us from generating inappropriate emotional and behavioral responses. Stress may cause the reduction of the GABAergic interneuronal network and the development of neuropsychological diseases. In this review, we summarize the recent evidence investigating the possible mechanisms underlying GABAergic control of the amygdala and its interaction with acute and chronic stress. Taken together, this study may contribute to future progress in finding new approaches to reverse the attenuation of GABAergic neurotransmission induced by stress in the amygdala.
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Affiliation(s)
- Fan Jie
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Guanghao Yin
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Wei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Modi Yang
- Department of Gastrointestinal Colorectal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Shuohui Gao
- Department of Gastrointestinal Colorectal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Jiayin Lv
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
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14
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Samuel N, Taub A, Paz R, Raz A. Implicit aversive memory under anaesthesia in animal models: a narrative review. Br J Anaesth 2018; 121:219-232. [DOI: 10.1016/j.bja.2018.05.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 12/23/2022] Open
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15
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Bender CL, Otamendi A, Calfa GD, Molina VA. Prior stress promotes the generalization of contextual fear memories: Involvement of the gabaergic signaling within the basolateral amygdala complex. Prog Neuropsychopharmacol Biol Psychiatry 2018; 83:18-26. [PMID: 29223783 DOI: 10.1016/j.pnpbp.2017.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/02/2017] [Accepted: 12/06/2017] [Indexed: 12/20/2022]
Abstract
Fear generalization occurs when a response, previously acquired with a threatening stimulus, is transferred to a similar one. However, it could be maladaptive when stimuli that do not represent a real threat are appraised as dangerous, which is a hallmark of several anxiety disorders. Stress exposure is a major risk factor for the occurrence of anxiety disorders and it is well established that it influences different phases of fear memory; nevertheless, its impact on the generalization of contextual fear memories has been less studied. In the present work, we have characterized the impact of acute restraint stress prior to contextual fear conditioning on the generalization of this fear memory, and the role of the GABAergic signaling within the basolateral amygdala complex (BLA) on the stress modulatory effects. We have found that a single stress exposure promoted the generalization of this memory trace to a different context that was well discriminated in unstressed conditioned animals. Moreover, this effect was dependent on the formation of a contextual associative memory and on the testing order (i.e., conditioning context first vs generalization context first). Furthermore, we observed that increasing GABA-A signaling by intra-BLA midazolam administration prior to the stressful session exposure prevented the generalization of fear memory, whereas intra-BLA administration of the GABA-A antagonist (Bicuculline), prior to fear conditioning, induced the generalization of fear memory in unstressed rats. We concluded that stress exposure, prior to contextual fear conditioning, promotes the generalization of fear memory and that the GABAergic transmission within the BLA has a critical role in this phenomenon.
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Affiliation(s)
- C L Bender
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - A Otamendi
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - G D Calfa
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - V A Molina
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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16
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PDE4D regulates Spine Plasticity and Memory in the Retrosplenial Cortex. Sci Rep 2018; 8:3895. [PMID: 29497131 PMCID: PMC5832851 DOI: 10.1038/s41598-018-22193-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 02/16/2018] [Indexed: 12/17/2022] Open
Abstract
The retrosplenial cortex (RSC) plays a critical role in episodic memory, but the molecular mechanisms governing plasticity in this structure are poorly understood. Diverse studies have demonstrated a role for RSC in acquisition, early consolidation and retrieval similar to the hippocampus (HC), as well as in systems consolidation similar to the anterior cingulate cortex. Here, we asked whether established molecular and structural substrates of memory consolidation in the HC also engage in RSC shortly after learning. We show striking parallels in training induced gene-activation in HC and RSC following contextual conditioning, which is blocked by systemic administration of an NMDA receptor antagonist. Long-term memory is enhanced by retrosplenial and hippocampal knockdown (KD) of the cAMP specific phosphodiesterase Pde4d. However, while training per se induces lasting spine changes in HC, this does not occur in RSC. Instead, increases in the number of mature dendritic spines are found in the RSC only if cAMP signaling is augmented by Pde4d KD, and spine changes are at least partially independent of training. This research highlights parallels and differences in spine plasticity mechanisms between HC and RSC, and provides evidence for a functional dissociation of the two.
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17
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Pai CS, Sharma PK, Huang HT, Loganathan S, Lin H, Hsu YL, Phasuk S, Liu IY. The Activating Transcription Factor 3 ( Atf3) Homozygous Knockout Mice Exhibit Enhanced Conditioned Fear and Down Regulation of Hippocampal GELSOLIN. Front Mol Neurosci 2018. [PMID: 29515366 PMCID: PMC5826182 DOI: 10.3389/fnmol.2018.00037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The genetic and molecular basis underlying fear memory formation is a key theme in anxiety disorder research. Because activating transcription factor 3 (ATF3) is induced under stress conditions and is highly expressed in the hippocampus, we hypothesize that ATF3 plays a role in fear memory formation. We used fear conditioning and various other paradigms to test Atf3 knockout mice and study the role of ATF3 in processing fear memory. The results demonstrated that the lack of ATF3 specifically enhanced the expression of fear memory, which was indicated by a higher incidence of the freeze response after fear conditioning, whereas the occurrence of spatial memory including Morris Water Maze and radial arm maze remained unchanged. The enhanced freezing behavior and normal spatial memory of the Atf3 knockout mice resembles the fear response and numbing symptoms often exhibited by patients affected with posttraumatic stress disorder. Additionally, we determined that after fear conditioning, dendritic spine density was increased, and expression of Gelsolin, the gene encoding a severing protein for actin polymerization, was down-regulated in the bilateral hippocampi of the Atf3 knockout mice. Taken together, our results suggest that ATF3 may suppress fear memory formation in mice directly or indirectly through mechanisms involving modulation of actin polymerization.
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Affiliation(s)
- Chia-Sheng Pai
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | - Pranao K Sharma
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Hsien-Ting Huang
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | | | - Heng Lin
- Department of Physiology, Taipei Medical University, Taipei, Taiwan
| | - Yu-Luan Hsu
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | - Sarayut Phasuk
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.,Department of Physiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Ingrid Y Liu
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan.,Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
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18
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Kaplan GB, Leite-Morris KA, Wang L, Rumbika KK, Heinrichs SC, Zeng X, Wu L, Arena DT, Teng YD. Pathophysiological Bases of Comorbidity: Traumatic Brain Injury and Post-Traumatic Stress Disorder. J Neurotrauma 2017; 35:210-225. [PMID: 29017388 DOI: 10.1089/neu.2016.4953] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The high rates of traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) diagnoses encountered in recent years by the United States Veterans Affairs Healthcare System have increased public awareness and research investigation into these conditions. In this review, we analyze the neural mechanisms underlying the TBI/PTSD comorbidity. TBI and PTSD present with common neuropsychiatric symptoms including anxiety, irritability, insomnia, personality changes, and memory problems, and this overlap complicates diagnostic differentiation. Interestingly, both TBI and PTSD can be produced by overlapping pathophysiological changes that disrupt neural connections termed the "connectome." The neural disruptions shared by PTSD and TBI and the comorbid condition include asymmetrical white matter tract abnormalities and gray matter changes in the basolateral amygdala, hippocampus, and prefrontal cortex. These neural circuitry dysfunctions result in behavioral changes that include executive function and memory impairments, fear retention, fear extinction deficiencies, and other disturbances. Pathophysiological etiologies can be identified using experimental models of TBI, such as fluid percussion or blast injuries, and for PTSD, using models of fear conditioning, retention, and extinction. In both TBI and PTSD, there are discernible signs of neuroinflammation, excitotoxicity, and oxidative damage. These disturbances produce neuronal death and degeneration, axonal injury, and dendritic spine dysregulation and changes in neuronal morphology. In laboratory studies, various forms of pharmacological or psychological treatments are capable of reversing these detrimental processes and promoting axonal repair, dendritic remodeling, and neurocircuitry reorganization, resulting in behavioral and cognitive functional enhancements. Based on these mechanisms, novel neurorestorative therapeutics using anti-inflammatory, antioxidant, and anticonvulsant agents may promote better outcomes for comorbid TBI and PTSD.
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Affiliation(s)
- Gary B Kaplan
- 1 Mental Health Service , VA Boston Healthcare System, Brockton, Massachusetts.,2 Department of Psychiatry, Boston University School of Medicine , Boston, Massachusetts.,3 Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine , Boston, Massachusetts
| | - Kimberly A Leite-Morris
- 2 Department of Psychiatry, Boston University School of Medicine , Boston, Massachusetts.,3 Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine , Boston, Massachusetts.,4 Research Service, VA Boston Healthcare System , Jamaica Plain, Massachusetts
| | - Lei Wang
- 5 Division of Spinal Cord Injury Research, VA Boston Healthcare System , West Roxbury, Massachusetts.,6 Departments of Physical Medicine and Rehabilitation and Neurosurgery, Harvard Medical School , Boston, Massachusetts
| | - Kendra K Rumbika
- 7 Research Service, VA Boston Healthcare System , West Roxbury, Massachusetts
| | - Stephen C Heinrichs
- 7 Research Service, VA Boston Healthcare System , West Roxbury, Massachusetts
| | - Xiang Zeng
- 5 Division of Spinal Cord Injury Research, VA Boston Healthcare System , West Roxbury, Massachusetts.,6 Departments of Physical Medicine and Rehabilitation and Neurosurgery, Harvard Medical School , Boston, Massachusetts
| | - Liquan Wu
- 5 Division of Spinal Cord Injury Research, VA Boston Healthcare System , West Roxbury, Massachusetts.,6 Departments of Physical Medicine and Rehabilitation and Neurosurgery, Harvard Medical School , Boston, Massachusetts
| | - Danielle T Arena
- 7 Research Service, VA Boston Healthcare System , West Roxbury, Massachusetts
| | - Yang D Teng
- 5 Division of Spinal Cord Injury Research, VA Boston Healthcare System , West Roxbury, Massachusetts.,6 Departments of Physical Medicine and Rehabilitation and Neurosurgery, Harvard Medical School , Boston, Massachusetts
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19
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GABAergic signaling within the Basolateral Amygdala Complex modulates resistance to the labilization/reconsolidation process. Neurobiol Learn Mem 2017; 144:166-173. [DOI: 10.1016/j.nlm.2017.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/29/2017] [Accepted: 06/24/2017] [Indexed: 01/08/2023]
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20
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Xu X, Garcia J, Ewalt R, Nason S, Pozzo-Miller L. The BDNF val-66-met Polymorphism Affects Neuronal Morphology and Synaptic Transmission in Cultured Hippocampal Neurons from Rett Syndrome Mice. Front Cell Neurosci 2017; 11:203. [PMID: 28751857 PMCID: PMC5508027 DOI: 10.3389/fncel.2017.00203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/27/2017] [Indexed: 12/02/2022] Open
Abstract
Brain-derived neurotrophic factor (Bdnf) has been implicated in several neurological disorders including Rett syndrome (RTT), an X-linked neurodevelopmental disorder caused by loss-of-function mutations in the transcriptional modulator methyl-CpG-binding protein 2 (MECP2). The human BDNF gene has a single nucleotide polymorphism (SNP)—a methionine (met) substitution for valine (val) at codon 66—that affects BDNF’s trafficking and activity-dependent release and results in cognitive dysfunction. Humans that are carriers of the met-BDNF allele have subclinical memory deficits and reduced hippocampal volume and activation. It is still unclear whether this BDNF SNP affects the clinical outcome of RTT individuals. To evaluate whether this BDNF SNP contributes to RTT pathophysiology, we examined the consequences of expression of either val-BDNF or met-BDNF on dendrite and dendritic spine morphology, and synaptic function in cultured hippocampal neurons from wildtype (WT) and Mecp2 knockout (KO) mice. Our findings revealed that met-BDNF does not increase dendritic growth and branching, dendritic spine density and individual spine volume, and the number of excitatory synapses in WT neurons, as val-BDNF does. Furthermore, met-BDNF reduces dendritic complexity, dendritic spine volume and quantal excitatory synaptic transmission in Mecp2 KO neurons. These results suggest that the val-BDNF variant contributes to RTT pathophysiology, and that BDNF-based therapies should take into consideration the BDNF genotype of the RTT individuals.
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Affiliation(s)
- Xin Xu
- Department of Neurobiology, Civitan International Research Center, University of Alabama at BirminghamBirmingham, AL, United States
| | - Jordi Garcia
- Department of Neurobiology, Civitan International Research Center, University of Alabama at BirminghamBirmingham, AL, United States
| | - Rachel Ewalt
- Department of Neurobiology, Civitan International Research Center, University of Alabama at BirminghamBirmingham, AL, United States
| | - Shelly Nason
- Department of Neurobiology, Civitan International Research Center, University of Alabama at BirminghamBirmingham, AL, United States
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, University of Alabama at BirminghamBirmingham, AL, United States
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21
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Decreased Glycogen Content Might Contribute to Chronic Stress-Induced Atrophy of Hippocampal Astrocyte volume and Depression-like Behavior in Rats. Sci Rep 2017; 7:43192. [PMID: 28233800 PMCID: PMC5324119 DOI: 10.1038/srep43192] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/20/2017] [Indexed: 01/08/2023] Open
Abstract
The involvement of brain glycogen in the progress of chronic stress-induced impairment of hippocampal astrocyte structural plasticity and depression-like behavior is yet to be clarified. The present study designed three experiments to determine the role of brain glycogen in the plasticity and behavioral consequences of chronic stress. Time course studies on brain glycogen, astrocytes, and behavioral responses to stress were conducted in Experiment 1. Chronic stress decreased the hippocampal glycogen levels, reduced astrocytic size and protrusion length in the hippocampus, and induced depression-like behavior. Glycogen synthase 1 mRNA in the hippocampus was silenced by lentiviral vector-based RNA interference (RNAi) in Experiment 2. This RNAi produced a lack of glycogen in the hippocampus, decreased the hippocampal astrocyte size, and induced depressive behavior in rats. The mechanisms of chronic stress-induced brain glycogen decrease were investigated in Experiment 3. Chronic stress promoted hippocampal glycogen breakdown and increased hippocampal glycogen synthesis. Results suggest that decreased glycogen content was associated with chronic stress-induced atrophy of hippocampal astrocyte size and depression-like behavior. Furthermore, the decrease of glycogen content in the hippocampus might be due to the compensation of glycogen synthesis for breakdown in an insufficient manner.
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22
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Ammassari-Teule M. Is structural remodeling in regions governing memory an univocal correlate of memory? Neurobiol Learn Mem 2016; 136:28-33. [DOI: 10.1016/j.nlm.2016.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 09/12/2016] [Accepted: 09/14/2016] [Indexed: 12/16/2022]
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23
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Evidence for an expanded time-window to mitigate a reactivated fear memory by tamoxifen. Eur Neuropsychopharmacol 2016; 26:1601-9. [PMID: 27554635 DOI: 10.1016/j.euroneuro.2016.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/25/2016] [Accepted: 08/05/2016] [Indexed: 12/22/2022]
Abstract
The mechanisms underpinning the persistence of emotional memories are inaccurately understood. Advancing the current level of understanding with regards to this aspect is of potential translational value for the treatment of post-traumatic stress disorder (PTSD), which stems from an abnormal aversive memory formation. Tamoxifen (TMX) is a drug used in chemotherapy for breast cancer and associated with poor cognitive performances. The present study investigated whether the systemic administration of TMX (1.0-50mg/kg) during and/or beyond the reconsolidation time-window could attenuate a reactivated contextual fear memory in laboratory animals. When administered 0, 6 or 9h (but not 12h) post-memory retrieval and reactivation, TMX (50mg/kg) reduced the freezing behavior in male rats re-exposed to the paired context on day 7, but not on day 1, suggesting a specific impairing effect on memory persistence. Importantly, this effect lasts up to 21 days, but it is prevented by omitting the memory retrieval or memory reactivation. When female rats in the diestrous or proestrous phase were used, the administration of TMX 6h after retrieving and reactivating the fear memory also impaired its persistence. Altogether, regardless of the gender, the present results indicate that the TMX is able to disrupt the persistence of reactivated fear memories in an expanded time-window, which could shed light on a new promising therapeutic strategy for PTSD.
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24
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Hidalgo C, Arias-Cavieres A. Calcium, Reactive Oxygen Species, and Synaptic Plasticity. Physiology (Bethesda) 2016; 31:201-15. [DOI: 10.1152/physiol.00038.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this review article, we address how activity-dependent Ca2+ signaling is crucial for hippocampal synaptic/structural plasticity and discuss how changes in neuronal oxidative state affect Ca2+ signaling and synaptic plasticity. We also analyze current evidence indicating that oxidative stress and abnormal Ca2+ signaling contribute to age-related synaptic plasticity deterioration.
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Affiliation(s)
- Cecilia Hidalgo
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
- Center of Molecular Studies of the Cell and Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Alejandra Arias-Cavieres
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
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25
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Abstract
Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.
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Affiliation(s)
- Ivan Izquierdo
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Cristiane R. G. Furini
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Jociane C. Myskiw
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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26
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Bender CL, Calfa GD, Molina VA. Astrocyte plasticity induced by emotional stress: A new partner in psychiatric physiopathology? Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:68-77. [PMID: 26320029 DOI: 10.1016/j.pnpbp.2015.08.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/07/2015] [Accepted: 08/08/2015] [Indexed: 01/18/2023]
Abstract
A growing body of evidence has demonstrated that astrocytes play a pivotal role in the normal functioning of the nervous system. This new conceptual framework has set the groundwork to be able to hypothesize that astrocytes could underlie signs and symptoms of mental diseases. Stress is a major risk factor in the etiology of several psychiatric diseases, such as anxiety disorders and depression. Hence, understanding the effects of stress on astrocytes and how these changes contribute to the development of psychiatric endophenotypes is crucial for both a better comprehension of mental illness and for potential targeted treatment of stress-related mental disorders. Here, we describe the currently used approaches and recent evidence showing astrocyte alterations induced by chronic and acute stress in animals. In addition, the relevance of these changes in stress-induced behavioral sequelae and human data linking astrocytes with neuropsychiatric disorders related to stress are also discussed. All together, the data indicate that astrocytes are also an important target of stress, with both chronic and acute stressors being able to alter the morphology or the expression of several astrocyte specific proteins in brain areas that are known to play a critical role in emotional processing, such as the prefrontal cortex, hippocampus and amygdala. Furthermore, different lines of evidences suggest that these changes may contribute, at less in part, to the behavioral consequences of stress.
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Affiliation(s)
- Crhistian L Bender
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, (5000) Córdoba, Argentina.
| | - Gaston D Calfa
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, (5000) Córdoba, Argentina
| | - Victor A Molina
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, (5000) Córdoba, Argentina
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27
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Post-extinction selective persistence of large dendritic spines in fear remodeled circuits may serve to reactivate fear. Curr Opin Neurobiol 2015; 35:1-5. [DOI: 10.1016/j.conb.2015.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 12/18/2022]
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28
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Watanabe S. Social factors modulate restraint stress induced hyperthermia in mice. Brain Res 2015; 1624:134-139. [DOI: 10.1016/j.brainres.2015.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 06/24/2015] [Accepted: 07/03/2015] [Indexed: 01/02/2023]
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Giachero M, Calfa GD, Molina VA. Hippocampal dendritic spines remodeling and fear memory are modulated by GABAergic signaling within the basolateral amygdala complex. Hippocampus 2015; 25:545-55. [DOI: 10.1002/hipo.22409] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Marcelo Giachero
- IFEC-CONICET, Departamento de Farmacología; Facultad de Ciencias Químicas, Universidad Nacional de Córdoba; Córdoba Argentina
| | - Gaston D. Calfa
- IFEC-CONICET, Departamento de Farmacología; Facultad de Ciencias Químicas, Universidad Nacional de Córdoba; Córdoba Argentina
| | - Victor A. Molina
- IFEC-CONICET, Departamento de Farmacología; Facultad de Ciencias Químicas, Universidad Nacional de Córdoba; Córdoba Argentina
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Beitnere U, Dzirkale Z, Isajevs S, Rumaks J, Svirskis S, Klusa V. Carnitine congener mildronate protects against stress- and haloperidol-induced impairment in memory and brain protein expression in rats. Eur J Pharmacol 2014; 745:76-83. [DOI: 10.1016/j.ejphar.2014.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 10/08/2014] [Accepted: 10/08/2014] [Indexed: 11/15/2022]
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Abstract
Neuroimaging studies have demonstrated reduced hippocampal volume in trauma-exposed individuals without posttraumatic stress disorder (PTSD). However, the implications of such a deficit in this non-clinical population are still unclear. Animal and human models of PTSD suggest that hippocampal deficit may result in impaired learning and use of associations between contextual information and aversive events. Previous study has shown that individuals with PTSD have a selective impairment in reversing the negative outcome of context-related information. The aim of this study was to test whether non-PTSD individuals who are repeatedly exposed to traumatic events display similar impairment. To that end, we compared the performance of active-duty firefighters who are frequently exposed to traumatic events as part of their occupational routine and civilian matched-controls with no history of trauma-exposure. We used a novel cue-context reversal paradigm, which separately evaluates reversal of negative and positive outcomes of cue and context-related information. As predicted, we found that while both trauma-exposed firefighters and unexposed matched-controls were able to acquire and retain stimulus-outcome associations, firefighters struggled to learn that a previously negative context is later associated with a positive outcome. This impairment did not correlate with levels of PTSD, anxiety or depressive symptoms. The results suggest that similar to individuals with PTSD, highly exposed individuals fail to associate traumatic outcomes with their appropriate context. This impairment may reflect a possible hidden price of repeated traumatic exposure, which is not necessarily associated with PTSD diagnosis, and may affect the way highly exposed individuals interpret and react to their environment.
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Heat exposure in female rats elicits abnormal fear expression and cellular changes in prefrontal cortex and hippocampus. Neurobiol Learn Mem 2014; 115:38-42. [PMID: 24859751 DOI: 10.1016/j.nlm.2014.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/10/2014] [Accepted: 05/13/2014] [Indexed: 12/11/2022]
Abstract
Despite a twofold higher prevalence of fear-related disorders in women, the neurobiological factors that modulate and drive fear expression are rarely studied in female animals. Fear conditioning and extinction are useful tools for dissecting these mechanisms, and here we tested the effects of environmental manipulations - four days of exposure to 31°C temperatures in the animal housing facility - on fear learning and memory exclusively in female rats. We found that heat exposure disrupted freezing to tone during fear conditioning, and elicited enhanced freezing during extinction and extinction retrieval. We also performed immunohistochemistry for c-fos expression in the infralimbic (IL) and prelimbic (PL) regions of the prefrontal cortex during extinction retrieval, and found that heat exposure induced a switch from IL-dominated activity to PL-dominated activity. Finally, morphological analysis of spines in hippocampal CA3 neurons revealed an increase in spine head diameter in heat-exposed animals, which may partly underlie the persistent freezing observed in these animals. Together, our data show that heat exposure can induce changes at behavioral, physiological, and structural levels, and add to a woefully lacking body of literature on fear processes in female animals.
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