1
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Ahmed S, Polis B, Jamwal S, Sanganahalli BG, MacDowell Kaswan Z, Islam R, Kim D, Bowers C, Giuliano L, Biederer T, Hyder F, Kaffman A. Transient impairment in microglial function causes sex-specific deficits in synaptic maturity and hippocampal function in mice exposed to early adversity. Brain Behav Immun 2024; 122:95-109. [PMID: 39134183 PMCID: PMC11402597 DOI: 10.1016/j.bbi.2024.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 08/04/2024] [Accepted: 08/08/2024] [Indexed: 08/17/2024] Open
Abstract
Abnormal development and function of the hippocampus are two of the most consistent findings in humans and rodents exposed to early-life adversity (ELA), with males often being more affected than females. Using the limited bedding (LB) paradigm as a rodent model of ELA, we found that male adolescent mice that had been exposed to LB exhibit significant deficits in contextual fear conditioning and synaptic connectivity in the hippocampus, which are not observed in females. This is linked to altered developmental refinement of connectivity, with LB severely impairing microglial-mediated synaptic pruning in the hippocampus of male and female pups on postnatal day 17 (P17), but not in adolescent P33 mice when levels of synaptic engulfment by microglia are substantially lower. Since the rodent hippocampus undergoes intense synaptic pruning during the second and third weeks of life, we investigated whether microglia are required for the synaptic and behavioral aberrations observed in adolescent LB mice. Indeed, transient ablation of microglia from P13-21 in normally developing mice caused sex-specific behavioral and synaptic abnormalities similar to those observed in adolescent LB mice. Furthermore, chemogenetic activation of microglia during the same period reversed the microglial-mediated phagocytic deficits at P17 and restored normal contextual fear conditioning and synaptic connectivity in adolescent LB male mice. Our data support an additional contribution of astrocytes in the sex-specific effects of LB, with increased expression of the membrane receptor MEGF10 and enhanced synaptic engulfment in hippocampal astrocytes of 17-day-old LB females, but not in LB male littermates. These findings suggest a potential compensatory mechanism that may explain the relative resilience of LB females. Collectively, our study highlights a novel role for glial cells in mediating sex-specific hippocampal deficits in a mouse model of ELA.
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Affiliation(s)
- Sahabuddin Ahmed
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Baruh Polis
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Sumit Jamwal
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Basavaraju G Sanganahalli
- Department of Radiology & Biomedical Imaging and Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
| | - Zoe MacDowell Kaswan
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Rafiad Islam
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Dana Kim
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Christian Bowers
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Lauryn Giuliano
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Thomas Biederer
- Department of Neurology, Yale School of Medicine, 100 College Street, New Haven, CT 06510, USA
| | - Fahmeed Hyder
- Department of Radiology & Biomedical Imaging and Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, 06519, USA
| | - Arie Kaffman
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA.
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2
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Ahmed S, Polis B, Kaffman A. Microglia: The Drunken Gardeners of Early Adversity. Biomolecules 2024; 14:964. [PMID: 39199352 PMCID: PMC11353196 DOI: 10.3390/biom14080964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 08/03/2024] [Accepted: 08/06/2024] [Indexed: 09/01/2024] Open
Abstract
Early life adversity (ELA) is a heterogeneous group of negative childhood experiences that can lead to abnormal brain development and more severe psychiatric, neurological, and medical conditions in adulthood. According to the immune hypothesis, ELA leads to an abnormal immune response characterized by high levels of inflammatory cytokines. This abnormal immune response contributes to more severe negative health outcomes and a refractory response to treatment in individuals with a history of ELA. Here, we examine this hypothesis in the context of recent rodent studies that focus on the impact of ELA on microglia, the resident immune cells in the brain. We review recent progress in our ability to mechanistically link molecular alterations in microglial function during a critical period of development with changes in synaptic connectivity, cognition, and stress reactivity later in life. We also examine recent research showing that ELA induces long-term alterations in microglial inflammatory response to "secondary hits" such as traumatic brain injury, substance use, and exposure to additional stress in adulthood. We conclude with a discussion on future directions and unresolved questions regarding the signals that modify microglial function and the clinical significance of rodent studies for humans.
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Affiliation(s)
| | | | - Arie Kaffman
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven, CT 06511, USA; (S.A.); (B.P.)
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3
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Ahmed S, Polis B, Jamwal S, Sanganahalli BG, Kaswan ZM, Islam R, Kim D, Bowers C, Giuliano L, Biederer T, Hyder F, Kaffman A. Transient Impairment in Microglial Function Causes Sex-Specific Deficits in Synaptic and Hippocampal Function in Mice Exposed to Early Adversity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580284. [PMID: 38405887 PMCID: PMC10888912 DOI: 10.1101/2024.02.14.580284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Abnormal development and function of the hippocampus are two of the most consistent findings in humans and rodents exposed to early life adversity, with males often being more affected than females. Using the limited bedding (LB) paradigm as a rodent model of early life adversity, we found that male adolescent mice that had been exposed to LB exhibit significant deficits in contextual fear conditioning and synaptic connectivity in the hippocampus, which are not observed in females. This is linked to altered developmental refinement of connectivity, with LB severely impairing microglial-mediated synaptic pruning in the hippocampus of male and female pups on postnatal day 17 (P17), but not in adolescent P33 mice when levels of synaptic engulfment by microglia are substantially lower. Since the hippocampus undergoes intense synaptic pruning during the second and third weeks of life, we investigated whether microglia are required for the synaptic and behavioral aberrations observed in adolescent LB mice. Indeed, transient ablation of microglia from P13-21, in normally developing mice caused sex-specific behavioral and synaptic abnormalities similar to those observed in adolescent LB mice. Furthermore, chemogenetic activation of microglia during the same period reversed the microglial-mediated phagocytic deficits at P17 and restored normal contextual fear conditioning and synaptic connectivity in adolescent LB male mice. Our data support an additional contribution of astrocytes in the sex-specific effects of LB, with increased expression of the membrane receptor MEGF10 and enhanced synaptic engulfment in hippocampal astrocytes of 17-day-old LB females, but not in LB male littermates. This finding suggests a potential compensatory mechanism that may explain the relative resilience of LB females. Collectively, these studies highlight a novel role for glial cells in mediating sex-specific hippocampal deficits in a mouse model of early-life adversity.
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Affiliation(s)
- Sahabuddin Ahmed
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Baruh Polis
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Sumit Jamwal
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Basavaraju G. Sanganahalli
- Department of Radiology & Biomedical Imaging and Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06519, USA
| | - Zoe MacDowell Kaswan
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Rafiad Islam
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Dana Kim
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Christian Bowers
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Lauryn Giuliano
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
| | - Thomas Biederer
- Department of Neurology, Yale School of Medicine, 100 College Street, New Haven, CT 06510, USA
| | - Fahmeed Hyder
- Department of Radiology & Biomedical Imaging and Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06519, USA
| | - Arie Kaffman
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, Suite 901, New Haven CT, 06511, USA
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Drulis‐Fajdasz D, Krzystyniak A, Puścian A, Pytyś A, Gostomska‐Pampuch K, Pudełko‐Malik N, Wiśniewski JŁ, Młynarz P, Miazek A, Wójtowicz T, Włodarczyk J, Duś‐Szachniewicz K, Gizak A, Wiśniewski JR, Rakus D. Glycogen phosphorylase inhibition improves cognitive function of aged mice. Aging Cell 2023; 22:e13928. [PMID: 37522798 PMCID: PMC10497847 DOI: 10.1111/acel.13928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/31/2023] [Accepted: 06/23/2023] [Indexed: 08/01/2023] Open
Abstract
Inhibition of glycogen breakdown blocks memory formation in young animals, but it stimulates the maintenance of the long-term potentiation, a cellular mechanism of memory formation, in hippocampal slices of old animals. Here, we report that a 2-week treatment with glycogen phosphorylase inhibitor BAY U6751 alleviated memory deficits and stimulated neuroplasticity in old mice. Using the 2-Novel Object Recognition and Novel Object Location tests, we discovered that the prolonged intraperitoneal administration of BAY U6751 improved memory formation in old mice. This was accompanied by changes in morphology of dendritic spines in hippocampal neurons, and by "rejuvenation" of hippocampal proteome. In contrast, in young animals, inhibition of glycogen degradation impaired memory formation; however, as in old mice, it did not alter significantly the morphology and density of cortical dendritic spines. Our findings provide evidence that prolonged inhibition of glycogen phosphorolysis improves memory formation of old animals. This could lead to the development of new strategies for treatment of age-related memory deficits.
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Affiliation(s)
| | - Adam Krzystyniak
- Laboratory of Cell BiophysicsNencki Institute of Experimental Biology, Polish Academy of SciencesWarsawPoland
| | - Alicja Puścian
- Nencki‐EMBL Partnership for Neural Plasticity and Brain Disorders – BRAINCITYNencki Institute of Experimental Biology, Polish Academy of SciencesWarsawPoland
| | - Agata Pytyś
- Laboratory of Cell BiophysicsNencki Institute of Experimental Biology, Polish Academy of SciencesWarsawPoland
| | - Kinga Gostomska‐Pampuch
- Department of Biochemistry and ImmunochemistryWroclaw Medical UniversityWroclawPoland
- Biochemical Proteomics Group, Department of Proteomics and Signal TransductionMax Planck Institute of BiochemistryMartinsriedGermany
| | - Natalia Pudełko‐Malik
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of ChemistryWroclaw University of Science and TechnologyWroclawPoland
| | - Jerzy Ł. Wiśniewski
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of ChemistryWroclaw University of Science and TechnologyWroclawPoland
| | - Piotr Młynarz
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of ChemistryWroclaw University of Science and TechnologyWroclawPoland
| | - Arkadiusz Miazek
- Laboratory of Tumor ImmunologyHirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of SciencesWroclawPoland
| | - Tomasz Wójtowicz
- Laboratory of Cell BiophysicsNencki Institute of Experimental Biology, Polish Academy of SciencesWarsawPoland
| | - Jakub Włodarczyk
- Laboratory of Cell BiophysicsNencki Institute of Experimental Biology, Polish Academy of SciencesWarsawPoland
| | - Kamila Duś‐Szachniewicz
- Department of Clinical and Experimental PathologyInstitute of General and Experimental Pathology, Wroclaw Medical UniversityWroclawPoland
| | - Agnieszka Gizak
- Department of Molecular Physiology and NeurobiologyUniversity of WroclawWroclawPoland
| | - Jacek R. Wiśniewski
- Biochemical Proteomics Group, Department of Proteomics and Signal TransductionMax Planck Institute of BiochemistryMartinsriedGermany
| | - Dariusz Rakus
- Department of Molecular Physiology and NeurobiologyUniversity of WroclawWroclawPoland
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5
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Kobayashi KS, Matsuo N. Persistent representation of the environment in the hippocampus. Cell Rep 2023; 42:111989. [PMID: 36640328 DOI: 10.1016/j.celrep.2022.111989] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/23/2022] [Accepted: 12/23/2022] [Indexed: 01/13/2023] Open
Abstract
In the hippocampus, environmental changes elicit rearrangement of active neuronal ensembles or remapping of place cells. However, it remains elusive how the brain ensures a consistent representation of a certain environment itself despite salient events occurring there. Here, we longitudinally tracked calcium dynamics of dorsal hippocampal CA1 neurons in mice subjected to contextual fear conditioning and extinction training. Overall population activities were significantly changed by fear conditioning and were responsive to footshocks and freezing. However, a small subset of neurons, termed environment cells, were consistently active in a specific environment irrespective of experiences. A decoder modeling study showed that these cells, but not place cells, were able to predict the environment to which the mouse was exposed. Environment cells might underlie the constancy of cognition for distinct environments across time and events. Additionally, our study highlights the functional heterogeneity of cells in the hippocampus.
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Affiliation(s)
- Kyogo S Kobayashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan.
| | - Naoki Matsuo
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan.
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6
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Reis AL, Hammond JH, Stevanovski I, Arnold JC, McGregor IS, Deveson IW, Gururajan A. Sex-specific transcriptomic and epitranscriptomic signatures of PTSD-like fear acquisition. iScience 2022; 25:104861. [PMID: 36039298 PMCID: PMC9418440 DOI: 10.1016/j.isci.2022.104861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/03/2022] [Accepted: 07/26/2022] [Indexed: 11/22/2022] Open
Abstract
Our understanding of the molecular pathology of posttraumatic stress disorder (PTSD) is evolving due to advances in sequencing technologies. With the recent emergence of Oxford Nanopore direct RNA-seq (dRNA-seq), it is now also possible to interrogate diverse RNA modifications, collectively known as the “epitranscriptome.”. Here, we present our analyses of the male and female mouse amygdala transcriptome and epitranscriptome, obtained using parallel Illumina RNA-seq and Oxford Nanopore dRNA-seq, associated with the acquisition of PTSD-like fear induced by Pavlovian cued-fear conditioning. We report significant sex-specific differences in the amygdala transcriptional response during fear acquisition and a range of shared and dimorphic epitranscriptomic signatures. Differential RNA modifications are enriched among mRNA transcripts associated with neurotransmitter regulation and mitochondrial function, many of which have been previously implicated in PTSD. Very few differentially modified transcripts are also differentially expressed, suggesting an influential, expression-independent role for epitranscriptional regulation in PTSD-like fear acquisition. PTSD-like trauma has sexually dimorphic effects on the amygdala transcriptome Most RNA modifications identified adhere to the known patterns associated with m6A There was enrichment of RNA modifications in neurological/PTSD-related genes There was little overlap between transcriptomic and epitranscriptomic signatures
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7
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Enhancing Endocannabinoid Signaling via β-Catenin in the Nucleus Accumbens Attenuates PTSD- and Depression-like Behavior of Male Rats. Biomedicines 2022; 10:biomedicines10081789. [PMID: 35892688 PMCID: PMC9394396 DOI: 10.3390/biomedicines10081789] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/14/2022] [Accepted: 07/20/2022] [Indexed: 12/15/2022] Open
Abstract
Inhibition of fatty acid amide hydrolase (FAAH), which increases anandamide levels, has been suggested as a potential treatment for stress-related conditions. We examined whether the stress-preventing effects of the FAAH inhibitor URB597 on behavior are mediated via β-catenin in the nucleus accumbens (NAc). Male rats were exposed to the shock and reminders model of PTSD and then treated with URB597 (0.4 mg/kg; i.p.). They were tested for anxiety- (freezing, startle response), depression-like behaviors (despair, social preference, anhedonia), and memory function (T-maze, social recognition). We also tested the involvement of the CB1 receptor (CB1r), β-catenin, and metabotropic glutamate receptor subtype 5 (mGluR5) proteins. URB597 prevented the shock- and reminders-induced increase in anxiety- and depressive-like behaviors, as well as the impaired memory via the CB1r-dependent mechanism. In the NAc, viral-mediated β-catenin overexpression restored the behavior of rats exposed to stress and normalized the alterations in protein levels in the NAc and the prefrontal cortex. Importantly, when NAc β-catenin levels were downregulated by viral-mediated gene transfer, the therapeutic-like effects of URB597 were blocked. We suggest a potentially novel mechanism for the therapeutic-like effects of FAAH inhibition that is dependent on β-catenin activation in the NAc in a PTSD rat model.
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Zoladz PR. Animal models for the discovery of novel drugs for post-traumatic stress disorder. Expert Opin Drug Discov 2020; 16:135-146. [PMID: 32921163 DOI: 10.1080/17460441.2020.1820982] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Existing pharmacological treatments for PTSD are limited and have been used primarily because of their effectiveness in other psychiatric conditions. To generate novel, PTSD specific pharmacotherapy, researchers must utilize animal models to assess the efficacy of experimental drugs. AREAS COVERED This review includes a discussion of factors that should be considered when developing an animal model of PTSD, as well as descriptions of the most commonly used models. Researchers have utilized physical stressors, psychological stressors, or a combination of the two to induce PTSD-like physiological and behavioral sequelae in animals. Such models have provided researchers with a valuable tool to examine the neurobiological mechanisms underlying the condition. EXPERT OPINION PTSD is a heterogeneous disorder that manifests as different symptom clusters in different individuals. Thus, there cannot be a one-size-fits-all approach to modeling the disorder in animals. Preclinical investigators must adopt a concentrated effort aimed at modeling specific PTSD subtypes and the distinct symptom profiles that result from specific types of human trauma. Moreover, researchers have focused so much on modeling a single PTSD syndrome in animals that studies examining only specific facets of the disorder are largely ignored. Future research employing animal models of PTSD requires greater focus on the nuances of PTSD.
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Affiliation(s)
- Phillip R Zoladz
- Psychology Program, the School of Health and Behavioral Sciences, Ohio Northern University , Ada, OH, USA
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9
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Guo KF, Dai M, Liu YM, Zhang JC, Chen YM, Ye H, Li MB, Mao RR, Cao J. Acute Administration of Methyleugenol Impairs Hippocampus-Dependent Contextual Fear Memory and Increases Anxiety-like Behavior in Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:7490-7497. [PMID: 32551566 DOI: 10.1021/acs.jafc.0c01863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Methyleugenol (ME) as a natural essential oil in many plant species is widely used in human food and beverage for its fragrance and possible beneficial health effects. Previous chronic or subacute studies in rodents show that ME mainly causes liver toxicity. However, whether and how acute ME affects the central nervous system still remain elusive. Here, we found that ME administrated into the hippocampus impaired the acquisition of hippocampus-dependent contextual fear memory in mice (ME vs control: repeated-measures two-way ANOVA, F(5,70) = 2.937, p < 0.05; Fisher test, p < 0.05, respectively, 53 ± 5.2% vs 73 ± 7.6% during trial 4 and 46.8 ± 6% vs 74.5 ± 9.3% during trial 5). Meanwhile, acute ME impaired hippocampal CA1 long-term potentiation (LTP; ME vs control: independent t-test, p < 0.01, 110.6 ± 1.8% vs 133.3 ± 5.6%) while facilitated long-term depression (LTD; p < 0.01, 75.7 ± 3.4% vs 88.6 ± 1.7%) in mice brain slices and inducing a decrease in learning-dependent phosphorylation of Ser831 (ME vs control: independent t-test, p < 0.001, 0.87 ± 0.03 vs 1.23 ± 0.03) and Ser845 (p < 0.01, 0.42 ± 0.07 vs 0.97 ± 0.14) sites of excitatory glutamate AMPA receptor subunit 1 (GluA1) in the hippocampus, which may be the underlying mechanisms of impairment of hippocampus-dependent learning. In addition, intrahippocampal infusion of ME also increased anxiety-like behaviors in mice. These results suggested that acute ME impaired the hippocampus function at behavioral, cellular, and molecular levels, indicating the potential risks of ME on the central nervous system.
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Affiliation(s)
- Kai-Fei Guo
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology and School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650504, China
- School of Agriculture, Yunnan University, Kunming, Yunnan 650504, China
| | - Man Dai
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology and School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650504, China
| | - Yi-Miao Liu
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology and School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650504, China
| | - Ji-Chuan Zhang
- Department of Basic Medicine, Medical School, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Yan-Mei Chen
- Department of Basic Medicine, Medical School, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Hui Ye
- School of Agriculture, Yunnan University, Kunming, Yunnan 650504, China
| | - Man-Bi Li
- Yunnan Institute of Environmental Sciences, Kunming, Yunnan 650034, China
| | - Rong-Rong Mao
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, Yunnan 650500, China
| | - Jun Cao
- Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology and School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650504, China
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10
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Nguyen PV, Gelinas JN. Noradrenergic gating of long-lasting synaptic potentiation in the hippocampus: from neurobiology to translational biomedicine. J Neurogenet 2018; 32:171-182. [DOI: 10.1080/01677063.2018.1497630] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Peter V. Nguyen
- Department of Physiology and Institute of Neuroscience & Mental Health, University of Alberta School of Medicine, Edmonton, Canada
| | - Jennifer N. Gelinas
- Department of Neurology and Institute for Genomic Medicine, College of Physicians & Surgeons of Columbia University, New York, NY,USA
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11
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Lovinger DM, Abrahao KP. Synaptic plasticity mechanisms common to learning and alcohol use disorder. ACTA ACUST UNITED AC 2018; 25:425-434. [PMID: 30115764 PMCID: PMC6097767 DOI: 10.1101/lm.046722.117] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/21/2018] [Indexed: 11/24/2022]
Abstract
Alcohol use disorders include drinking problems that span a range from binge drinking to alcohol abuse and dependence. Plastic changes in synaptic efficacy, such as long-term depression and long-term potentiation are widely recognized as mechanisms involved in learning and memory, responses to drugs of abuse, and addiction. In this review, we focus on the effects of chronic ethanol (EtOH) exposure on the induction of synaptic plasticity in different brain regions. We also review findings indicating that synaptic plasticity occurs in vivo during EtOH exposure, with a focus on ex vivo electrophysiological indices of plasticity. Evidence for effects of EtOH-induced or altered synaptic plasticity on learning and memory and EtOH-related behaviors is also reviewed. As this review indicates, there is much work needed to provide more information about the molecular, cellular, circuit, and behavioral consequences of EtOH interactions with synaptic plasticity mechanisms.
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Affiliation(s)
- David M Lovinger
- Laboratory for Integrative Neuroscience, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892, USA
| | - Karina P Abrahao
- Laboratory for Integrative Neuroscience, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892, USA
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12
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Item-Place Encoding Through Hippocampal Long-Term Depression. HANDBOOK OF OBJECT NOVELTY RECOGNITION 2018. [DOI: 10.1016/b978-0-12-812012-5.00019-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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The interhemispheric CA1 circuit governs rapid generalisation but not fear memory. Nat Commun 2017; 8:2190. [PMID: 29259187 PMCID: PMC5736595 DOI: 10.1038/s41467-017-02315-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/20/2017] [Indexed: 12/30/2022] Open
Abstract
Encoding specificity theory predicts most effective recall by the original conditions at encoding, while generalization endows recall flexibly under circumstances which deviate from the originals. The CA1 regions have been implicated in memory and generalization but whether and which locally separated mechanisms are involved is not clear. We report here that fear memory is quickly formed, but generalization develops gradually over 24 h. Generalization but not fear memory is impaired by inhibiting ipsilateral (ips) or contralateral (con) CA1, and by optogenetic silencing of the ipsCA1 projections onto conCA1. By contrast, in vivo fEPSP recordings reveal that ipsCA1–conCA1 synaptic efficacy is increased with delay over 24 h when generalization is formed but it is unchanged if generalization is disrupted. Direct excitation of ipsCA1–conCA1 synapses using chemogenetic hM3Dq facilitates generalization formation. Thus, rapid generalization is an active process dependent on bilateral CA1 regions, and encoded by gradual synaptic learning in ipsCA1–conCA1 circuit. Previous work has documented a slow form of memory generalization although a rapid one is demanded. Here the authors elucidate the role of the interhemispheric CA1-CA1 projection in a form of rapid generalization of contextual fear memory via gradual potentiation of these synapses over 24 h.
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14
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Bali A, Jaggi AS. Electric foot shock stress: a useful tool in neuropsychiatric studies. Rev Neurosci 2015; 26:655-77. [DOI: 10.1515/revneuro-2015-0015] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/03/2015] [Indexed: 11/15/2022]
Abstract
AbstractElectric foot shock is a complex stressor with both physical and emotional components. It has been employed as an important tool to develop diverse animal models in the field of psychopharmacology. The electric foot shock paradigm includes acute or chronic exposures of shocks of varying intensity and duration on an electrified grid floor in an electric foot shock apparatus. Research evidence reveals that foot shocks of varying intensity produce behavioral and neurochemical changes reflecting depression, anxiety, and post-traumatic stress disorder (PTSD) in humans. Animals generally do not habituate to foot shocks in comparison to other stressors, including loud noise, bright light, and hot and cold temperatures. Additionally, it offers an experimental advantage of control over intensity and duration; therefore, by varying its application parameters, different disorder models have been created. Electric foot shock fear conditioning-induced ultrasonic vocalization and fear-potentiated startle have been explored to develop models of anxiety and panic. Similarly, fear conditioning in the form of foot shock exposure followed by situational reminders has been used to develop a model of PTSD. Electric foot shock-induced conflict has been explored to develop operant conflict models (Geller-Seifter and Vogel tests), which in turn are pharmacologically validated to screen potential anti-anxiety agents. Inescapable electric shock-induced ‘learned helplessness’ mimics the symptomology of depression, and this phenomenon has been employed to develop the model of depression. The present review describes the pharmacologically validated models of anxiety, depression, and PTSD involving electric foot shock as an aversive stimulus.
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Affiliation(s)
- Anjana Bali
- 1Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, India
| | - Amteshwar Singh Jaggi
- 1Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, India
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15
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Shan LL, Guo H, Song NN, Jia ZP, Hu XT, Huang JF, Ding YQ, Richter-Levin G, Richter-Levine G, Zhou QX, Xu L. Light exposure before learning improves memory consolidation at night. Sci Rep 2015; 5:15578. [PMID: 26493375 PMCID: PMC4616152 DOI: 10.1038/srep15578] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/28/2015] [Indexed: 01/12/2023] Open
Abstract
Light is recently recognized as a modulator able to activate the hippocampus and modulate memory processing, but little is known about the molecular mechanisms. Here, we report that in mice, a short pulse of white light before learning dramatically improves consolidation of contextual fear memory during the night. The light exposure increases hippocampal active p21-activated kinase 1 (PAK1) and CA1 long-term potentiation (LTP). These light effects are abolished in PAK1 knockout and dominant-negative transgenic mice, but preserved by expression of constitutively active PAK1 in the hippocampus. Our results indicate that light can act as a switch of PAK1 activity that modulate CA1 LTP and thereby memory consolidation without affecting learning and short-term memory.
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Affiliation(s)
- Li-Li Shan
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Guo
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ning-Ning Song
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Neurobiology, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China
| | - Zheng-Ping Jia
- Neurosciences &Mental Health, The Hospital for Sick Children, Department of Physiology, Faculty of Medicine, University of Toronto, 555 University Ave., Toronto, Ontario 5MS 3H2, Canada
| | - Xin-Tian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,CAS Center for Excellence in Brain Science, 320 Yue Yang Road, Shanghai, 200031, China
| | - Jing-Fei Huang
- KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming 650223, China
| | - Yu-Qiang Ding
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Neurobiology, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China
| | | | - Gal Richter-Levine
- The Institute for the Study of Affective Neuroscience, and Sagol Department of Neurobiology and Department of Psychology, University of Haifa, Haifa, Israel
| | - Qi-Xin Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China
| | - Lin Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,CAS Center for Excellence in Brain Science, 320 Yue Yang Road, Shanghai, 200031, China
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16
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Han H, Peng Y, Dong Z. d-Serine rescues the deficits of hippocampal long-term potentiation and learning and memory induced by sodium fluoroacetate. Pharmacol Biochem Behav 2015; 133:51-6. [DOI: 10.1016/j.pbb.2015.03.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/23/2015] [Accepted: 03/29/2015] [Indexed: 01/12/2023]
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17
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Jiang L, Mao R, Zhou Q, Yang Y, Cao J, Ding Y, Yang Y, Zhang X, Li L, Xu L. Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory. Mol Neurobiol 2015; 53:1247-1253. [DOI: 10.1007/s12035-015-9093-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/12/2015] [Indexed: 11/24/2022]
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18
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Hendriksen H, Olivier B, Oosting RS. From non-pharmacological treatments for post-traumatic stress disorder to novel therapeutic targets. Eur J Pharmacol 2014; 732:139-58. [DOI: 10.1016/j.ejphar.2014.03.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 03/17/2014] [Accepted: 03/24/2014] [Indexed: 10/25/2022]
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19
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Gao J, Wang H, Liu Y, Li YY, Chen C, Liu LM, Wu YM, Li S, Yang C. Glutamate and GABA imbalance promotes neuronal apoptosis in hippocampus after stress. Med Sci Monit 2014; 20:499-512. [PMID: 24675061 PMCID: PMC3976216 DOI: 10.12659/msm.890589] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Background People who experience traumatic events have an increased risk of post-traumatic stress disorder (PTSD). However, PTSD-related pathological changes in the hippocampus and prefrontal cortex remain poorly understood. Material/Methods We investigated the effect of a PTSD-like animal model induced by severe stress. The experimental rats received 20 inescapable electric foot shocks in an enclosed box for a total of 6 times in 3 days. The physiological state (body weight and plasma corticosterone concentrations), emotion, cognitive behavior, brain morphology, apoptosis, and balance of gamma-aminobutyric acid (GABA) and glutamate in the hippocampus and prefrontal cortex were observed. Cell damages were examined with histological staining (HE, Nissl, and silver impregnation), while apoptosis was analyzed with flow cytometry using an Annexin V and propidium iodide (PI) binding and terminal deoxynucleotidyl transferase mediated-dUTP nick end labeling (TUNEL) method. Results In comparison with the sham litter-mates, the stressed rats showed decreased body weight, inhibition of hypothalamic-pituitary-adrenal (HPA) axis activation, increase in freezing response to trauma reminder, hypoactivity and anxiety-like behaviors in elevated plus maze and open field test, poor learning in Morris water maze, and shortened latency in hot-plate test. There were significant damages in the hippocampus but not in the prefrontal cortex. Imbalance between glutamate and GABA was more evident in the hippocampus than in the prefrontal cortex. Conclusions These results suggest that neuronal apoptosis in the hippocampus after severe traumatic stress is related to the imbalance between glutamate and GABA. Such modifications may resemble the profound changes observed in PTSD patients.
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Affiliation(s)
- Jie Gao
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - He Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Yuan Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Ying-Yu Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Can Chen
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Liang-Ming Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Ya-Min Wu
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Sen Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
| | - Ce Yang
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China (mainland)
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20
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Kim BK, Seo JH. Treadmill exercise alleviates post-traumatic stress disorder-induced impairment of spatial learning memory in rats. J Exerc Rehabil 2013; 9:413-9. [PMID: 24278894 PMCID: PMC3836542 DOI: 10.12965/jer.130058] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 08/20/2013] [Accepted: 08/20/2013] [Indexed: 11/22/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) is a condition which occurs after a person has experienced unusual stress. The neurons in the hippocampus are especially vulnerable to the PTSD. In the present study, the effect of treadmill exercise on spatial learning memory and cell proliferation in the hippocampus of rats with PTSD. Radial 8-arm maze test and immunohistochemistr for 5-bromo-2'-deoxyridine (BrdU) and double-cortin (DCX) were conducted for this experiment. For the inducing PTSD, the rats were exposure to 0.2 mA electric foot shock for 7 consecutive days. Electric foot shock continued 6 seconds, repeated 10 times with a 30 sec interval per one trial, and repeated 3 trials per day. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 4 weeks, stating one day after finishing last electric food shock. Presently, the PTSD rats showed longer time of successful performance, higher error number, and lower correct number in the radial-8-arm maze test. Cell proliferation and DCX expression in the hippocampal dentate gyrus were suppressed in the PTSD rats. In contrast, treadmill exercise alleviated PTSD-induced impairment of spatial learning memory. The rats performed treadmill exercise showed longer time of successful performance, higher error number, and lower correct number in the radial-8-arm maze test. Treadmill exercise also enhanced cell proliferation and DCX expression in the hippocampal dentate gyrus of PTSD rats. The present study demonstrated that treadmill exercise ameliorated PTSD-induced memory impairment through enhancing cell proliferation in the hippocampus.
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Affiliation(s)
- Bo-Kyun Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
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21
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Burke HM, Robinson CM, Wentz B, McKay J, Dexter KW, Pisansky JM, Talbot JN, Zoladz PR. Sex-specific impairment of spatial memory in rats following a reminder of predator stress. Stress 2013; 16:469-76. [PMID: 23550585 DOI: 10.3109/10253890.2013.791276] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
It has been suggested that cognitive impairments exhibited by people with post-traumatic stress disorder (PTSD) result from intrusive, flashback memories transiently interfering with ongoing cognitive processing. Researchers have further speculated that females are more susceptible to developing PTSD because they form stronger traumatic memories than males, hence females may be more sensitive to the negative effects of intrusive memories on cognition. We have examined how the reminder of a naturalistic stress experience would affect rat spatial memory and if sex was a contributing factor to such effects. Male and female Sprague-Dawley rats were exposed, without contact, to an adult female cat for 30 min. Five weeks later, the rats were trained to locate a hidden platform in the radial-arm water maze and given a single long-term memory test trial 24 h later. Before long-term memory testing, the rats were given a 30-min reminder of the cat exposure experienced 5 weeks earlier. The results indicated that the stress reminder impaired spatial memory in the female rats only. Control manipulations revealed that this effect was not attributable to the original cat exposure adversely impacting learning that occurred 5 weeks later, or to merely exposing rats to a novel environment or predator-related cues immediately before testing. These findings provide evidence that the reminder of a naturalistic stressful experience can impair cognitive processing in rats; moreover, since female rats were more susceptible to the memory-impairing effects of the stress reminder, the findings could lend insight into the existing sex differences in susceptibility to PTSD.
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Affiliation(s)
- Hanna M Burke
- Department of Psychology and Sociology, Raabe College of Pharmacy, Ohio Northern University, Ada, OH 45810, USA
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22
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Hawley WR, Grissom EM, Patel JM, Hodges KS, Dohanich GP. Reactivation of an aversive memory modulates learning strategy preference in male rats. Stress 2013; 16:73-86. [PMID: 22533611 DOI: 10.3109/10253890.2012.683466] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reminders of an aversive event adversely impact retrieval of hippocampus-dependent memories and exacerbate stress-induced levels of anxiety. Interestingly, stress and anxiety shift control over learning away from the hippocampus and toward the striatum. The aims of the current study were to determine whether spatial memory and learning strategy are impacted by reminders of a stressor. Adult male Long-Evans rats (N = 47) were subjected to an inhibitory avoidance (IA) training trial in which 32 rats were exposed (3 s) to a single inescapable electrical footshock (0.6 mA). Prior to the retention trial of a Y-maze task and the probe trials of two different learning strategy tasks, some of the rats that were exposed to the footshock (n = 17) were reminded of the stressor on an IA retrieval trial. Both groups of rats exposed to the initial stressor exhibited hypoactivity, but no impairment in spatial memory, on the Y-maze task conducted 1 week after exposure to the footshock. One month after exposure to footshock, both groups of rats exposed to the initial stressor tended to prefer a striatum-dependent learning strategy on a water T-maze task. However, 2 months after exposure to footshock, only shocked rats that were reminded of the stressor exhibited a preference for a striatum-dependent learning strategy on a visible-platform water maze task, which corresponded with lower levels of activity in an open field. The results indicate that reminders of a stressor perpetuate the deleterious effects of stress on affective and cognitive processes.
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Affiliation(s)
- Wayne R Hawley
- Department of Psychology, Tulane University, New Orleans, LA 70118, USA
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23
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Li Z, Richter-Levin G. Stimulus intensity-dependent modulations of hippocampal long-term potentiation by basolateral amygdala priming. Front Cell Neurosci 2012; 6:21. [PMID: 22586371 PMCID: PMC3343647 DOI: 10.3389/fncel.2012.00021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 04/17/2012] [Indexed: 01/12/2023] Open
Abstract
There is growing realization that the relationship between memory and stress/emotionality is complicated, and may include both memory enhancing and memory impairing aspects. It has been suggested that the underlying mechanisms involve amygdala modulation of hippocampal synaptic plasticity, such as long-term potentiation (LTP). We recently reported that while in CA1 basolateral amygdala (BLA) priming impaired theta stimulation induced LTP, it enhanced LTP in the dentate gyrus (DG). However, emotional and stressfull experiences were found to activate synaptic plasticity within the BLA, raising the possibility that BLA modulation of other brain regions may be altered as well, as it may depend on the way the BLA is activated or is responding. In previous studies BLA priming stimulation was relatively weak (1 V, 50 μs pulse duration). In the present study we assessed the effects of two stronger levels of BLA priming stimulation (1 V or 2 V, 100 μs pulse duration) on LTP induction in hippocampal DG and CA1, in anesthetized rats. Results show that 1V-BLA priming stimulation enhanced but 2V-BLA priming stimulation impaired DG LTP; however, both levels of BLA priming stimulation impaired CA1 LTP, suggesting that modulation of hippocampal synaptic plasticity by amygdala is dependent on the degree of amygdala activation. These findings suggest that plasticity-induced within the amygdala, by stressful experiences induces a form of metaplasticity that would alter the way the amygdala may modulate memory-related processes in other brain areas, such as the hippocampus.
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Affiliation(s)
- Zexuan Li
- Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel
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24
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Li H, Wu X, Bai Y, Huang Y, He W, Dong Z. Unilateral lesion of dorsal hippocampus in adult rats impairs contralateral long-term potentiation in vivo and spatial memory in the early postoperative phase. Behav Brain Res 2012; 230:428-32. [DOI: 10.1016/j.bbr.2012.02.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 02/24/2012] [Accepted: 02/25/2012] [Indexed: 10/28/2022]
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25
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Foster TC. Dissecting the age-related decline on spatial learning and memory tasks in rodent models: N-methyl-D-aspartate receptors and voltage-dependent Ca2+ channels in senescent synaptic plasticity. Prog Neurobiol 2012; 96:283-303. [PMID: 22307057 DOI: 10.1016/j.pneurobio.2012.01.007] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 01/09/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
Abstract
In humans, heterogeneity in the decline of hippocampal-dependent episodic memory is observed during aging. Rodents have been employed as models of age-related cognitive decline and the spatial water maze has been used to show variability in the emergence and extent of impaired hippocampal-dependent memory. Impairment in the consolidation of intermediate-term memory for rapidly acquired and flexible spatial information emerges early, in middle-age. As aging proceeds, deficits may broaden to include impaired incremental learning of a spatial reference memory. The extent and time course of impairment has been be linked to senescence of calcium (Ca²⁺) regulation and Ca²⁺-dependent synaptic plasticity mechanisms in region CA1. Specifically, aging is associated with altered function of N-methyl-D-aspartate receptors (NMDARs), voltage-dependent Ca²⁺ channels (VDCCs), and ryanodine receptors (RyRs) linked to intracellular Ca²⁺ stores (ICS). In young animals, NMDAR activation induces long-term potentiation of synaptic transmission (NMDAR-LTP), which is thought to mediate the rapid consolidation of intermediate-term memory. Oxidative stress, starting in middle-age, reduces NMDAR function. In addition, VDCCs and ICS can actively inhibit NMDAR-dependent LTP and oxidative stress enhances the role of VDCC and RyR-ICS in regulating synaptic plasticity. Blockade of L-type VDCCs promotes NMDAR-LTP and memory in older animals. Interestingly, pharmacological or genetic manipulations to reduce hippocampal NMDAR function readily impair memory consolidation or rapid learning, generally leaving incremental learning intact. Finally, evidence is mounting to indicate a role for VDCC-dependent synaptic plasticity in associative learning and the consolidation of remote memories. Thus, VDCC-dependent synaptic plasticity and extrahippocampal systems may contribute to incremental learning deficits observed with advanced aging.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience, Evelyn F. and William L. McKnight Brain Institute, University of Florida, PO Box 100244, Gainesville, FL 32610-0244, USA. ,
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Schenk GJ, Vreugdenhil E, Hubens CJY, Veldhuisen B, de Kloet ER, Oitzl MS. Hippocampal CARP over-expression solidifies consolidation of contextual fear memories. Physiol Behav 2010; 102:323-31. [PMID: 21130104 DOI: 10.1016/j.physbeh.2010.11.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/15/2010] [Accepted: 11/18/2010] [Indexed: 01/13/2023]
Abstract
The Doublecortin-Like Kinase (DCLK) gene is involved in neuronal migration during development. Through alternative splicing the DCLK gene also produces a transcript called Ca(2+)/calmodulin dependent protein kinase (CaMK)-related peptide (CARP) that is expressed exclusively during adulthood in response to neuronal activity. The function of CARP, however, is poorly understood. To study CARP function, we have generated transgenic mice with over-expression of the CARP transcript in, amongst other brain areas, the hippocampus. We aimed to characterize possible behavioral adaptations of these mice by using a Pavlovian fear conditioning approach. This type of fear conditioning, in which both the hippocampus and amygdala are critically involved, allows studying the formation and extinction of fear related memories. We here report on the behavioral adaptations of two distinct transgenic lines: one with high levels of CARP in the hippocampus and amygdala, whilst the other has high levels of CARP in the hippocampal formation, but not in the amygdala. We tested both mouse lines separately by comparing them to their wild-type littermate controls. We provide evidence suggesting consolidation of contextual fear memories is strengthened in mice of both transgenic lines.
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Affiliation(s)
- Geert J Schenk
- Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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Raineki C, Holman PJ, Debiec J, Bugg M, Beasley A, Sullivan RM. Functional emergence of the hippocampus in context fear learning in infant rats. Hippocampus 2010; 20:1037-46. [PMID: 19739248 PMCID: PMC2891848 DOI: 10.1002/hipo.20702] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The hippocampus is a part of the limbic system and is important for the formation of associative memories, such as acquiring information about the context (e.g., the place where an experience occurred) during emotional learning (e.g., fear conditioning). Here, we assess whether the hippocampus is responsible for pups' newly emerging context learning. In all experiments, postnatal day (PN) 21 and PN24 rat pups received 10 pairings of odor-0.5 mA shock or control unpaired odor-shock, odor only, or shock only. Some pups were used for context, cue or odor avoidance tests, while the remaining pups were used for c-Fos immunohistochemistry to assess hippocampal activity during acquisition. Our results show that cue and odor avoidance learning were similar at both ages, while contextual fear learning and learning-associated hippocampal (CA1, CA3, and dentate gyrus) activity (c-Fos) only occurred in PN24 paired pups. To assess a causal relationship between the hippocampus and context conditioning, we infused muscimol into the hippocampus, which blocked acquisition of context fear learning in the PN24 pups. Muscimol or vehicle infusions did not affect cue learning or aversion to the odor at PN21 or PN24. The results suggest that the newly emerging contextual learning exhibited by PN24 pups is supported by the hippocampus.
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Affiliation(s)
- Charlis Raineki
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, USA.
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Motanis H, Maroun M. Exposure to a novel context following contextual fear conditioning enhances the induction of hippocampal long-term potentiation. Eur J Neurosci 2010; 32:840-6. [DOI: 10.1111/j.1460-9568.2010.07334.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Radwańska K, Tudor-Jones AA, Mizuno K, Pereira GS, Lucchesi W, Alfano I, Łach A, Kaczmarek L, Knapp S, Giese KP. Differential regulation of CaMKII inhibitor beta protein expression after exposure to a novel context and during contextual fear memory formation. GENES BRAIN AND BEHAVIOR 2010; 9:648-57. [PMID: 20487031 DOI: 10.1111/j.1601-183x.2010.00595.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Understanding of the molecular basis of long-term fear memory (fear LTM) formation provides targets in the treatment of emotional disorders. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is one of the key synaptic molecules involved in fear LTM formation. There are two endogenous inhibitor proteins of CaMKII, CaMKII N alpha and N beta, which can regulate CaMKII activity in vitro. However, the physiological role of these endogenous inhibitors is not known. Here, we have investigated whether CaMKII N beta protein expression is regulated after contextual fear conditioning or exposure to a novel context. Using a novel CaMKII N beta-specific antibody, CaMKII N beta expression was analysed in the naïve mouse brain as well as in the amygdala and hippocampus after conditioning and context exposure. We show that in naïve mouse forebrain CaMKII N beta protein is expressed at its highest levels in olfactory bulb, prefrontal and piriform cortices, amygdala and thalamus. The protein is expressed both in dendrites and cell bodies. CaMKII N beta expression is rapidly and transiently up-regulated in the hippocampus after context exposure. In the amygdala, its expression is regulated only by contextual fear conditioning and not by exposure to a novel context. In conclusion, we show that CaMKII N beta expression is differentially regulated by novelty and contextual fear conditioning, providing further insight into molecular basis of fear LTM.
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Affiliation(s)
- K Radwańska
- Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, London, UK
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Zoladz PR, Woodson JC, Haynes VF, Diamond DM. Activation of a remote (1-year old) emotional memory interferes with the retrieval of a newly formed hippocampus-dependent memory in rats. Stress 2010; 13:36-52. [PMID: 19658031 DOI: 10.3109/10253890902853123] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The persistent intrusion of remote traumatic memories in people with post-traumatic stress disorder (PTSD) may contribute to the impairment of their ongoing hippocampal and prefrontal cortical functioning. In the current work, we have developed a rodent analogue of the intrusive memory phenomenon. We studied the influence of the activation of a remote traumatic memory in rats on their ability to retrieve a newly formed hippocampus-dependent memory. Adult male Sprague-Dawley rats were given inhibitory avoidance (IA) training, and then 24 h or 1, 6 or 12 months later, the same rats were trained to learn, and then remember across a 30-min delay period, the location of a hidden escape platform in the radial-arm water maze (RAWM). When IA-trained rats spent the 30-min delay period in the IA apparatus, they exhibited intact remote (1-year old) memory of the shock experience. More importantly, activation of the rats' memory of the shock experience profoundly impaired their ability to retrieve the newly formed spatial memory of the hidden platform location in the RAWM. Our finding that reactivation of a remote emotional memory exerted an intrusive effect on new spatial memory processing in rats provides a novel approach toward understanding how intrusive memories of traumatic experiences interfere with ongoing cognitive processing in people with PTSD.
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Kavushansky A, Ben-Shachar D, Richter-Levin G, Klein E. Physical stress differs from psychosocial stress in the pattern and time-course of behavioral responses, serum corticosterone and expression of plasticity-related genes in the rat. Stress 2009; 12:412-25. [PMID: 19929444 DOI: 10.1080/10253890802556081] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Stressors differ in their physiological and behavioral outcomes. One of the major mechanisms by which stressors affect the brain and behavior is alteration in neuronal plasticity. We investigated in the rat the effects of a single exposure to psychophysical (electrical foot shock) vs. psychological (social defeat) stressors on anxiety- and depression-related behaviors, serum levels of corticosterone and the expression of plasticity-related genes CAM-L1, CREB, GAP-43, and laminin in the prefrontal cortex (PFC), the amygdala and the hippocampus. Rats were examined for 24 h or 1 week after the exposure to stress. Footshocks enhanced anxiety-related behaviors, whereas social defeat induced depression-related behaviors at both time points and less pronounced anxiety 1 week post-exposure. Serum corticosterone concentrations were enhanced 24 h after shocks, but only 1 week after exposure to the social stressor. Moreover, the shock-stressed rats exhibited decreased CAM-L1 protein level in the hippocampus 24 h post-exposure and decreased GAP-43 protein level in the PFC 1 week post-exposure. By contrast, the social stressor enhanced expression of the plasticity-related proteins in the amygdala and the hippocampus, mostly 1 week after the exposure. These results indicate stressor-specific time-dependent changes in different neuronal pathways, and suggest consideration of a cause-specific approach to the treatment of stress-related disorders.
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Affiliation(s)
- Alexandra Kavushansky
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center, B. Rappaport Faculty of Medicine, Bat Galim, Technion, Haifa, 31096, Israel
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Differential modulation of hippocampal plasticity in a non-noxious conflict model for anxiety. Neuroscience 2009; 162:863-9. [DOI: 10.1016/j.neuroscience.2009.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 06/08/2009] [Accepted: 06/09/2009] [Indexed: 11/22/2022]
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Mao RR, Tian M, Yang YX, Zhou QX, Xu L, Cao J. Effects of pentylenetetrazol-induced brief convulsive seizures on spatial memory and fear memory. Epilepsy Behav 2009; 15:441-4. [PMID: 19570727 DOI: 10.1016/j.yebeh.2009.05.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/27/2009] [Accepted: 05/31/2009] [Indexed: 10/20/2022]
Abstract
Previous studies have demonstrated that in the pentylenetetrazol (PTZ) kindling model, recurrent seizures either impair or have no effect on learning and memory. However, the effects of brief seizures on learning and memory remain unknown. Here, we found that a single injection of a convulsive dose of PTZ (50 mg/kg, ip) induced brief seizures in Sprague-Dawley rats. Administration of PTZ before training impaired the acquisition of spatial memory in the Morris water maze (MWM) and fear memory in contextual fear conditioning. However, the administration of PTZ immediately after training did not affect memory consolidation in either task. These findings suggest that brief seizures have different effects on acquisition and consolidation of spatial and fear memory.
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Affiliation(s)
- Rong-Rong Mao
- Key Laboratory of Animal Models and Human Disease Mechanisms and Laboratory of Learning and Memory, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, People's Republic of China
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Bai HY, Cao J, Liu N, Xu L, Luo JH. Sexual behavior modulates contextual fear memory through dopamine D1/D5 receptors. Hippocampus 2009; 19:289-98. [PMID: 18853437 DOI: 10.1002/hipo.20505] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Traumatic events always lead to aversive emotional memory, i.e., fear memory. In contrast, positive events in daily life such as sex experiences seem to reduce aversive memory after aversive events. Thus, we hypothesized that post-traumatic pleasurable experiences, especially instinctive behaviors such as sex, might modulate traumatic memory through a memory competition mechanism. Here, we first report that male rats persistently expressed much lower fear responses when exposed to females, but not when exposed to males, for 24 h immediately after contextual fear conditioning. Remarkably, this effect of sexual behavior was blocked by either systemic or intrahippocampal injection of the dopamine D1/D5 receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390) and was mimicked by systemic but not intrahippocampal injection of the D1/D5 receptor agonist R(+)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol hydrochloride (SKF39393). Furthermore, as a candidate mechanism underlying contextual fear memory, the impaired induction of hippocampal long-term potentiation (LTP) elicited by conditioned fear was rescued in male rats immediately exposed to female but not male rats for 24 h. Systemic injection of the dopamine D1/D5 receptor antagonist SCH23390 or agonist SKF38393 prevented or mimicked the effect of sexual behavior on the impaired induction of hippocampal LTP. Thus, our finding suggests that dopaminergic functions may, at least partially, govern competition between contextual fear and enjoyable memories through the modulation of hippocampal LTP.
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Affiliation(s)
- Hua-Yi Bai
- Department of Neurobiology, Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
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Lasting changes in social behavior and amygdala function following traumatic experience induced by a single series of foot-shocks. Psychoneuroendocrinology 2008; 33:1198-210. [PMID: 18656313 DOI: 10.1016/j.psyneuen.2008.06.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 06/10/2008] [Accepted: 06/11/2008] [Indexed: 11/21/2022]
Abstract
Neuronal plasticity within the amygdala mediates many behavioral effects of traumatic experience, and this brain region also controls various aspects of social behavior. However, the specific involvement of the amygdala in trauma-induced social deficits has never been systematically investigated. We exposed rats to a single series of electric foot-shocks--a frequently used model of trauma--and studied their behavior in the social avoidance and psychosocial stimulation tests (non-contact versions of the social interaction test) at different time intervals. Social interaction-induced neuronal activation patterns were studied in the prefrontal cortex (orbitofrontal and medial), amygdala (central, medial, and basolateral), dorsal raphe and locus coeruleus. Shock exposure markedly inhibited social behavior in both tests. The effect lasted at least 4 weeks, and amplified over time. As shown by c-Fos immunocytochemistry, social interactions activated all the investigated brain areas. Traumatic experience exacerbated this activation in the central and basolateral amygdala, but not in other regions. The tight correlation between the social deficit and amygdala activation patterns suggest that the two phenomena were associated. A real-time PCR study showed that CRF mRNA expression in the amygdala was temporarily reduced 14, but not 1 and 28 days after shock exposure. In contrast, amygdalar NK1 receptor mRNA expression increased throughout. Thus, the trauma-induced social deficits appear to be associated with, and possibly caused by, plastic changes in fear-related amygdala subdivisions.
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Enhanced contextual fear memory in central serotonin-deficient mice. Proc Natl Acad Sci U S A 2008; 105:11981-6. [PMID: 18695238 DOI: 10.1073/pnas.0801329105] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Central serotonin (5-HT) dysregulation contributes to the susceptibility for mental disorders, including depression, anxiety, and posttraumatic stress disorder, and learning and memory deficits. We report that the formation of hippocampus-dependent spatial memory is compromised, but the acquisition and retrieval of contextual fear memory are enhanced, in central 5-HT-deficient mice. Genetic deletion of serotonin in the brain was achieved by inactivating Lmx1b selectively in the raphe nuclei of the brainstem, resulting in a near-complete loss of 5-HT throughout the brain. These 5-HT-deficient mice exhibited no gross abnormality in brain structures and had normal locomotor activity. Spatial learning in the Morris water maze was unaffected, but the retrieval of spatial memory was impaired. In contrast, contextual fear learning and memory induced by foot-shock conditioning was markedly enhanced, but this enhancement could be prevented by intracerebroventricular administration of 5-HT. Foot shock impaired long-term potentiation and facilitated long-term depression in hippocampal slices in WT mice but had no effect in 5-HT-deficient mice. Furthermore, bath application of 5-HT in 5-HT-deficient mice restored foot shock-induced alterations of hippocampal synaptic plasticity. Thus, central 5-HT regulates hippocampus-dependent contextual fear memory, and 5-HT modulation of hippocampal synaptic plasticity may be the underlying mechanism. The enhanced fear memory in 5-HT-deficient mice supports the notion that 5-HT deficiency confers susceptibility to posttraumatic stress disorder in humans.
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Gao Y, Han H, Xu R, Cao J, Luo J, Xu L. Effects of prolonged exposure to context following contextual fear conditioning on synaptic properties in rat hippocampal slices. Neurosci Res 2008; 61:385-9. [DOI: 10.1016/j.neures.2008.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2007] [Revised: 04/11/2008] [Accepted: 04/16/2008] [Indexed: 11/16/2022]
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Tamaki K, Yamada K, Nakamichi N, Taniura H, Yoneda Y. Transient suppression of progenitor cell proliferation through NMDA receptors in hippocampal dentate gyrus of mice with traumatic stress experience. J Neurochem 2008; 105:1642-55. [DOI: 10.1111/j.1471-4159.2008.05253.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Kluge C, Stoppel C, Szinyei C, Stork O, Pape HC. Role of the somatostatin system in contextual fear memory and hippocampal synaptic plasticity. Learn Mem 2008; 15:252-60. [PMID: 18391186 DOI: 10.1101/lm.793008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Somatostatin has been implicated in various cognitive and emotional functions, but its precise role is still poorly understood. Here, we have made use of mice with somatostatin deficiency, based upon genetic invalidation or pharmacologically induced depletion, and Pavlovian fear conditioning in order to address the contribution of the somatostatin system to associative fear memory. The results demonstrate an impairment of foreground and background contextual but not tone fear conditioning in mice with targeted ablation of the somatostatin gene. These deficits were associated with a decrease in long-term potentiation in the CA1 area of the hippocampus. Both the behavioral and the electrophysiological phenotypes were mimicked in wild-type mice through application of the somatostatin-depleting substance cysteamine prior to fear training, whereas no further deficits were observed upon application in the somatostatin null mutants. These results suggest that the somatostatin system plays a critical role in the acquisition of contextual fear memory, but not tone fear learning, and further highlights the role of hippocampal synaptic plasticity for information processing concerning contextual information.
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Affiliation(s)
- Christian Kluge
- Institute of Physiology I (Neurophysiology), Westfälische Wilhelms-University Münster, 48149 Münster, Germany
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Mikics E, Baranyi J, Haller J. Rats exposed to traumatic stress bury unfamiliar objects--a novel measure of hyper-vigilance in PTSD models? Physiol Behav 2008; 94:341-8. [PMID: 18339410 DOI: 10.1016/j.physbeh.2008.01.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 01/24/2008] [Accepted: 01/29/2008] [Indexed: 10/22/2022]
Abstract
Electric shocks lead to lasting behavioral deficits in rodents, and as such are often used to model post-traumatic stress disorder (PTSD) in the laboratory. Here we show that a single exposure of rats to 3 mA-strong shocks results in a marked social avoidance that lasts at least 28 days; moreover, the response intensifies over time. In an attempt to study the impact of cue reminders on the behavior of shocked rats, we administered shocks in the presence of a highly conspicuous, 10 cm-large object. This object was introduced into the home cage of rats 28 days after shock exposure. Shocked rats manipulated the object considerably less than controls. More importantly, however, the object was buried by shocked rats. This behavior was virtually absent in controls. The response strongly depended on the intensity of shocks, and was robust. Rats shocked with 3 mA currents spent 40% of time burying the object, which was often hardly visible at the end of the 5 min test. Subsequent experiments demonstrated that the response was not cue-specific as unfamiliar objects were also buried. Rats are well known to bury dangerous objects; the shock-prod burying test of anxiety is based on this response. Behavioral similarities with this test and the differences from the marble-burying behavior of mice suggest that traumatized rats bury unfamiliar objects in defense, and the response can be interpreted as a sign of hyper-vigilance. We further suggest that object burying can be used as a sign of hyper-vigilance in models of PTSD.
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Affiliation(s)
- Eva Mikics
- Department of Behavioral Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Matsumoto M, Togashi H, Konno K, Koseki H, Hirata R, Izumi T, Yamaguchi T, Yoshioka M. Early postnatal stress alters the extinction of context-dependent conditioned fear in adult rats. Pharmacol Biochem Behav 2007; 89:247-52. [PMID: 18262260 DOI: 10.1016/j.pbb.2007.12.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 12/11/2007] [Accepted: 12/14/2007] [Indexed: 11/16/2022]
Abstract
Fear extinction is hypothesized to be a learning process based on a new inhibitory memory. The present study was conducted to elucidate the effect of early postnatal stress on the extinction of context-dependent fear memory in adult rats, with a focus on the serotonergic system. Extinction was estimated by the expression of freezing behavior during repeated extinction trials (i.e., repeated exposure to contextual fear conditioning) on consecutive days. The decrease in fear expression was attenuated in adult rats that had been subjected to footshock (FS) at the third postnatal week (3wFS), but not in those exposed to footshock at the second postnatal week (2wFS). The decreased attenuation of freezing behavior observed in 3wFS was abolished by repeated treatment with the partial N-methyl-D-aspartate receptor agonist D-cycloserine (15 mg/kg, i.p., for 4 days), which has been shown to facilitate cue-dependent extinction. Repeated treatment with the serotonin 5-hydroxytryptamine-1A (5-HT(1A)) receptor agonist tandospirone (1 mg/kg, i.p., for 4 days) prevented the expression of freezing behavior in 3wFS, whereas diazepam treatment (1 mg/kg, i.p., for 4 days) in 3wFS did not. These results suggest that exposure to early postnatal stress at the third week is responsible for attenuating extinction of contextual fear conditioning and is mediated by a serotonergic 5-HT(1A) receptor mechanism. In other words, exposure to traumatic events during the early postnatal period might precipitate long-lasting alterations in synaptic function that underlie extinction processes of context-dependent fear memory.
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Affiliation(s)
- Machiko Matsumoto
- Department of Pharmacological Science, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan.
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Foster TC, Kumar A. Susceptibility to induction of long-term depression is associated with impaired memory in aged Fischer 344 rats. Neurobiol Learn Mem 2007; 87:522-35. [PMID: 17276704 PMCID: PMC1896085 DOI: 10.1016/j.nlm.2006.12.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 02/03/2023]
Abstract
The current study employed aged and young male Fischer 344 rats to examine the relationship between long-term depression (LTD), age, and memory. Memory performance was measured on two tasks that are sensitive to hippocampal function; inhibitory avoidance and spatial discrimination on the Morris water maze. The slope of the extracellular excitatory postsynaptic field potential was recorded from CA3-CA1 synapses in hippocampal slices. Low frequency stimulation (LFS) induced a modest LTD only in aged animals under standard recording conditions. The decrease in synaptic transmission examined only in aged animals correlated with memory scores on the spatial task and LTD was not observed in aged animals with the highest memory scores. LTD induction was facilitated by increasing the Ca(2+)/Mg(2+) ratio of the recording medium or employing a paired-pulse stimulation paradigm. Age differences disappeared when LFS was delivered under conditions of elevated Ca(2+)/Mg(2+) in the recording medium. Using multiple induction episodes under conditions which facilitate LTD-induction, no age-related difference was observed in the maximum level of LTD. The results indicate that the increased susceptibility to LTD induction is associated with impaired memory and results from a shift in the induction process. The possible relationship between LTD and memory function is discussed.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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Rossato JI, Zinn CG, Furini C, Bevilaqua LRM, Medina JH, Cammarota M, Izquierdo I. A link between the hippocampal and the striatal memory systems of the brain. AN ACAD BRAS CIENC 2007; 78:515-23. [PMID: 16936940 DOI: 10.1590/s0001-37652006000300011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 02/03/2006] [Indexed: 11/22/2022] Open
Abstract
Two major memory systems have been recognized over the years (Squire 1987): the declarative memory system, which is under the control of the hippocampus and related temporal lobe structures, and the procedural or habit memory system, which is under the control of the striatum and its connections. Most if not all learning tasks studied in animals, however, involve either the performance or the suppression of movement; this, if learned well, may be viewed as having become a habit. It is agreed that memory rules change from their first association to those that take place when the task is mastered. Does this change of rules involve a switch from one memory system to another? Here we will comment on: 1) reversal learning in the Morris water maze (MWM), in which the declarative or spatial component of a task is changed but the procedural component (to swim to safety) persists and needs to be re-linked with a different set of spatial cues; and 2) a series of observations on an inhibitory avoidance task that indicate that the brain systems involved change with further learning.
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Affiliation(s)
- Janine I Rossato
- Centro de Memória, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil
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Liu L, Zhang S, Zhu Y, Fu Q, Zhu Y, Gong Y, Ohtsu H, Luo J, Wei E, Chen Z. Improved learning and memory of contextual fear conditioning and hippocampal CA1 long-term potentiation in histidine decarboxylase knock-out mice. Hippocampus 2007; 17:634-41. [PMID: 17534971 DOI: 10.1002/hipo.20305] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Some studies suggest that the histaminergic system plays an important role in learning and memory. However, the results seem to be controversial in many behavioral tasks. In the present study, we used HDC knockout (HDC-KO) mice to investigate the effects of long-term histamine deficiency on learning and memory in contextual fear conditioning. We found that HDC-KO mice exhibited improved contextual fear from 1 day after training and this lasted for at least 14 days when compared with the wild-type (WT) controls. Cued fear was also improved 2 days after training in HDC-KO mice. Moreover, injection of histamine (intracerebroventricularly, 10 microg/mouse) immediately after training reversed the improvement in contextual fear conditioning when tested 1 day after training. Electrophysiological data showed that hippocampal CA1 long-term potentiation (LTP) in HDC-KO mice was much greater than that in WT mice, and paired-pulse facilitation decreased 2 h after LTP induction in HDC-KO mice. In contrast, HDC-KO mice showed smaller LTP than did WT mice 1 day after training. Hippocampal glutamate levels significantly increased in HDC-KO mice 1 and 4 days after training. The results indicated that histamine deficiency may improve consolidation of contextual fear conditioning. This improvement may be due to the increased hippocampal CA1 LTP, and presynaptic glutamate release. The relationship between behavior and synaptic plasticity provides support for the involvement of activity-dependent LTP in learning and memory.
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Affiliation(s)
- Luying Liu
- Department of Pharmacology and Neurobiology, School of Medicine, Zhejiang University, Hangzhou 310058, China
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Dong Z, Cao J, Xu L. Opiate withdrawal modifies synaptic plasticity in subicular-nucleus accumbens pathway in vivo. Neuroscience 2006; 144:845-54. [PMID: 17141960 DOI: 10.1016/j.neuroscience.2006.10.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Revised: 10/10/2006] [Accepted: 10/11/2006] [Indexed: 12/23/2022]
Abstract
Subiculum receives output of hippocampal CA1 neurons and projects glutamatergic synapses onto nucleus accumbens (NAc), the subicular-NAc pathway linking memory and reward system. It is unknown whether morphine withdrawal influences synaptic plasticity in the subicular-NAc pathway. Here, we recorded the field excitatory postsynaptic potential (EPSP) within the shell of NAc by stimulating ventral subiculum in anesthetized adult rats. We found that high frequency stimulation (HFS, 200 Hz) induced long-term potentiation (LTP) but low frequency stimulation (LFS, 1 Hz) failed to induce long-term depression (LTD) in control animals. However, behavioral stress enabled LFS to induce a reliable LTD (sLTD) that was dependent on the glucocorticoid receptors. Both LTP and sLTD were prevented by the N-methyl-d-aspartate receptor antagonist AP-5. After repeated morphine treatment for 12 days, acute withdrawal (12 h) impaired LTP but had no effect on sLTD; prolonged withdrawal (4 days) restored the LTP but impaired the sLTD. Remarkably, basal synaptic efficacy reflected by baseline EPSP amplitude was potentiated in acute withdrawal but was depressed in prolonged withdrawal. Thus, acute and prolonged opiate withdrawal may cause endogenous LTP and LTD in the subicular-NAc pathway that occludes the subsequent induction of synaptic plasticity, demonstrating adaptive changes of the NAc functions during opiate withdrawal.
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Affiliation(s)
- Z Dong
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Sciences, 32 Jiaochang Donglu, Kunming 650223, Yunnan, PR China
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Saltzman W, Hogan BK, Abbott DH. Diminished cortisol levels in subordinate female marmosets are associated with altered central drive to the hypothalamic-pituitary-adrenal axis. Biol Psychiatry 2006; 60:843-9. [PMID: 16499881 DOI: 10.1016/j.biopsych.2005.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Revised: 12/06/2005] [Accepted: 12/15/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Female marmosets offer a promising primate model of stress-related hypocortisolism, as they undergo chronic reductions in circulating cortisol after becoming subordinate in a social group. In this study, we treated dominant and subordinate female marmosets with the cortisol synthesis inhibitor metyrapone and corticotropin-releasing factor (CRF) to characterize the effects of subordination on central regulation of the hypothalamic-pituitary-adrenal (HPA) axis. METHODS Seven dominant and six subordinate female marmosets received CRF (6 microg/kg, intravenous [IV]), following pretreatment with metyrapone (75 mg/kg, by mouth [PO]) or water. Plasma adrenocorticotropic hormone (ACTH) and cortisol concentrations were determined before metyrapone or water treatment and before, 1 hour after, and 2 hours after CRF treatment. RESULTS Following metyrapone treatment, subordinates had similar cortisol levels to dominants but significantly higher ACTH levels. During CRF challenges, cortisol concentrations were lower and ACTH concentrations higher in subordinates, although net integrated responses to CRF did not differ. Cortisol-to-ACTH ratios were consistently lower in subordinates. CONCLUSIONS These results confirm previous findings of low cortisol concentrations and blunted adrenal responsiveness in subordinates and suggest that when differences in cortisol levels are eliminated, subordinates exhibit exaggerated hypothalamic drive to the pituitary. These neuroendocrine alterations in subordinate marmosets resemble those in posttraumatic stress disorder patients and adult survivors of child abuse.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology and Neuroscience Graduate Program, University of California, Riverside, California 92521, USA.
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47
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Izquierdo I, Bevilaqua LRM, Rossato JI, Bonini JS, Da Silva WC, Medina JH, Cammarota M. The connection between the hippocampal and the striatal memory systems of the brain: A review of recent findings. Neurotox Res 2006; 10:113-21. [PMID: 17062373 DOI: 10.1007/bf03033240] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Two major memory systems have been recognized over the years (Squire, in Memory and Brain, 1987): the declarative memory system, which is under the control of the hippocampus and related temporal lobe structures, and the procedural or habit memory system, which is under the control of the striatum and its connections (Mishkin et al., in Neurobiology of Learning by G Lynch et al., 1984; Knowlton et al., Science 273:1399, 1996). Most if not all learning tasks studied in animals, however, involve either the performance or the suppression of movement. Animals acquire connections between environmental or discrete sensory cues (conditioned stimuli, CSs) and emotionally or otherwise significant stimuli (unconditioned stimuli, USs). As a result, they learn to perform or to inhibit the performance of certain motor responses to the CS which, when learned well, become what can only be called habits (Mishkin et al., 1984): to regularly walk or swim to a place or away from a place, or to inhibit one or several forms of movement. These responses can be viewed as conditioned responses (CRs) and may sometimes be very complex. This is of course also seen in humans: people learn how to play on a keyboard in response to a mental or written script and perform the piano or write a text; with practice, the performance improves and eventually reaches a high criterion and becomes a habit, performed almost if not completely without awareness. Commuting to school in a big city in the shortest possible time and eschewing the dangers is a complex learning that children acquire to the point of near-perfection. It is agreed that the rules that connect the perception of the CS and the expression of the CR change from their first association to those that take place when the task is mastered. Does this change of rules involve a switch from one memory system to another? Are different brain systems used the first time one plays a sonata or goes to school as compared with the 100th time? Here we will comment on: 1) reversal learning in the Morris water maze (MWM), in which the declarative or spatial component of a task is changed but the procedural component (to swim) persists and needs to be re-linked with a different set of spatial cues; and 2) a series of observations on an inhibitory avoidance task that indicate that the brain systems involved change with further learning.
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Affiliation(s)
- I Izquierdo
- Centro de Memoria, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Andar (90610-000) Porto Alegre, RS, Brasil
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48
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Yang J, Han H, Cui M, Wang L, Cao J, Li L, Xu L. Acute behavioural stress facilitates long-term depression in temporoammonic-CA1 pathway. Neuroreport 2006; 17:753-7. [PMID: 16641682 DOI: 10.1097/01.wnr.0000209044.66482.c5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Behavioural stress facilitates long-term depression in Schaffer collaterals-CA1 pathway, but it is unknown whether it influences long-term depression in temporoammonic fibres-CA1. Here, we report that low-frequency stimulation induced long-term depression and foot shock stress before slice preparation facilitated long-term depression in both pathways of young rat slices. When the field excitatory postsynaptic potentials were recorded by stimulating the two pathways alternately and low-frequency stimulation was given to the two pathways simultaneously, a reliable long-term depression was induced in Schaffer collaterals-CA1 but a reliable long-term potentiation took place in temporoammonic fibres-CA1. Interestingly, foot shock stress now enabled low-frequency stimulation to induce reliable long-term depressions in both pathways. These findings suggested that acute behavioural stress facilitated long-term depressions in both pathways and disrupted the interactions between pathways.
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Affiliation(s)
- Jianli Yang
- Mental Health Institute of the 2nd Xiangya Hospital, Central South University, Changsha, PR China
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49
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Zhong WX, Dong ZF, Tian M, Cao J, Xu L, Luo JH. N-methyl-d-aspartate receptor-dependent long-term potentiation in CA1 region affects synaptic expression of glutamate receptor subunits and associated proteins in the whole hippocampus. Neuroscience 2006; 141:1399-413. [PMID: 16766131 DOI: 10.1016/j.neuroscience.2006.04.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Revised: 03/12/2006] [Accepted: 04/28/2006] [Indexed: 11/29/2022]
Abstract
Long term potentiation in hippocampus, evoked by high-frequency stimulation, is mediated by two major glutamate receptor subtypes, alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate receptors and N-methyl-D-aspartate receptors. Receptor subunit composition and its interaction with cytoplasmic proteins constitute different pathways regulating synaptic plasticity. Here, we provide further evidence that N-methyl-D-aspartate receptor-mediated long term potentiation evoked at hippocampal CA1 region of rats induced by high-frequency stimulation of the Schaffer collateral-commissural pathway in vivo is not dependent on N-methyl-D-aspartate receptor subunit NR2B. Applying semi-quantitative immunoblotting, we found that in the whole tetanized hippocampus, synaptic expression of the N-methyl-D-aspartate and alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate receptor subunits (NR1, NR2A, glutamate receptor 1) and their associated partners, e.g. synaptic associated protein 97, postsynaptic density protein 95, alpha subunit of Ca2+/calmodulin-dependent protein kinase II, neuronal nitricoxide synthase, increased 180 min post-high-frequency stimulation. Moreover, phosphorylation of Ca2+/calmodulin-dependent protein kinase II at thr286 and glutamate receptor 1 at ser831 was increased 30 min post-high-frequency stimulation and blocked by N-methyl-D-aspartate receptor antagonists (AP-5 and MK-801). In sham group and controls, these changes were not observed. The expression of several other synaptic proteins (NR2B, glutamate receptors 2/3, N-ethylmaleimide sensitive factor) was not affected by long term potentiation induction. In hippocampal homogenates, the level of these proteins remained unchanged. These data indicate that N-methyl-D-aspartate receptor-dependent long term potentiation in CA1 region in vivo mainly affects the synaptic expression of glutamate receptor subunits and associated proteins in the whole hippocampus. The alteration of molecular aspects can play a role in regulating the long-lasting synaptic modification in hippocampal long term potentiation in vivo.
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Affiliation(s)
- W X Zhong
- Department of Neurobiology, Zhejiang University School of Medicine, 353 Yanan Road, Hangzhou 310006, PR China
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50
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Funk D, Harding S, Juzytsch W, Lê AD. Effects of unconditioned and conditioned social defeat on alcohol self-administration and reinstatement of alcohol seeking in rats. Psychopharmacology (Berl) 2005; 183:341-9. [PMID: 16254734 DOI: 10.1007/s00213-005-0194-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 08/30/2005] [Indexed: 11/29/2022]
Abstract
RATIONALE AND OBJECTIVES We and others have shown that a stressor commonly used in laboratory studies, intermittent footshock, reinstates alcohol seeking in a rat relapse model. The effects of more ethologically relevant stressors on reinstatement have not been examined. Here, we characterized the effects of social defeat (a naturalistic stressor) or a cue associated with the defeat experience on reinstatement of alcohol seeking. We also examined the effect of unconditioned and conditioned social defeat on alcohol self-administration. METHODS Rats were trained to self-administer alcohol (12% w/v, 1 h day(-1)), and after stable responding, one group of animals received five exposures to social defeat paired with peppermint odor prior to daily self-administration sessions. After three more self-administration sessions, these rats were tested for the effects of the peppermint odor cue on self-administration. In another group of rats, the effects of three daily exposures to social defeat paired with peppermint odor on extinction of responding were examined. After further extinction sessions, the effect of the odor cue on reinstatement was tested in these animals. The acute effect of social defeat on reinstatement was examined in another group of animals. RESULTS Acute exposure to social defeat decreased alcohol self-administration, reduced rates of responding during extinction, and did not reinstate alcohol seeking. Exposure to a discrete odor cue previously paired with social defeat decreased alcohol self-administration but induced modest reinstatement of alcohol seeking. CONCLUSIONS Results provide the first demonstration of reinstatement of alcohol seeking by a cue paired with social defeat and are also in agreement with previous findings on the suppressive effect of social defeat stress on alcohol self-administration.
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Affiliation(s)
- D Funk
- Department of Neurosciences, Center for Addiction and Mental Health (CAMH), 33 Russell St., Toronto, Ontario, Canada M5S 2S1.
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