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Florido A, Perez-Caballero L, Velasco ER, Molina P, Marin-Blasco I, Andero R. Direct and Indirect Measurements of Sex Hormones in Rodents During Fear Conditioning. Curr Protoc 2021; 1:e102. [PMID: 33950571 DOI: 10.1002/cpz1.102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fear conditioning (FC) is a widely accepted tool for the assessment of learning and memory processes in rodents related to normal and dysregulated acquired fear. The study of sex differences in fear learning and memory is vast and currently increasing. Sex hormones have proven to be crucial for fear memory formation in males and females, and several methods have been developed to assess this hormonal state in rats and mice. Herein, we explain a routine FC and extinction protocol, together with the evaluation of sex hormonal state in male and female rodents. We explain three protocols for the evaluation of this hormonal state directly from blood samples extracted during the procedure or indirectly through histological verification of the estrous cycle for females or behavioral assessment of social hierarchies in males. Although females have typically been considered to present great variability in sex hormones, it is highlighted that sex hormone assessment in males is as variable as in females and equally important for fear memory formation. The readout of these protocols has had a great impact on different fields of fear learning and memory study and appears essential when studying FC. The proven interaction with drugs involved in the modulation of these processes makes sex hormone assessment during FC a valuable tool for the development of effective treatments for fear-related disorders in men and women. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Fear conditioning and fear extinction Basic Protocol 2: Blood collection for direct measurement of sex hormone levels in fear conditioning Basic Protocol 3: Indirect measurement of sex hormones in females during fear conditioning Basic Protocol 4: Assessment of dominance status in males before a fear conditioning protocol Support Protocol: Construction of a confrontation tube.
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Affiliation(s)
- Antonio Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Laura Perez-Caballero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Eric Raúl Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Patricia Molina
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Unitat de Fisiologia Animal (Departament de Biologia Cel·lular, Fisiologia i Immunologia), Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Ignacio Marin-Blasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Raül Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
- Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- ICREA, Barcelona, Spain
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Stefanelli G, Azam AB, Walters BJ, Brimble MA, Gettens CP, Bouchard-Cannon P, Cheng HYM, Davidoff AM, Narkaj K, Day JJ, Kennedy AJ, Zovkic IB. Learning and Age-Related Changes in Genome-wide H2A.Z Binding in the Mouse Hippocampus. Cell Rep 2018; 22:1124-1131. [PMID: 29386101 PMCID: PMC5820781 DOI: 10.1016/j.celrep.2018.01.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 12/08/2017] [Accepted: 01/05/2018] [Indexed: 02/04/2023] Open
Abstract
Histone variants were recently discovered to regulate neural plasticity, with H2A.Z emerging as a memory suppressor. Using whole-genome sequencing of the mouse hippocampus, we show that basal H2A.Z occupancy is positively associated with steady-state transcription, whereas learning-induced H2A.Z removal is associated with learning-induced gene expression. AAV-mediated H2A.Z depletion enhanced fear memory and resulted in gene-specific alterations of learning-induced transcription, reinforcing the role of H2A.Z as a memory suppressor. H2A.Z accumulated with age, although it remained sensitive to learning-induced eviction. Learning-related H2A.Z removal occurred at largely distinct genes in young versus aged mice, suggesting that H2A.Z is subject to regulatory shifts in the aged brain despite similar memory performance. When combined with prior evidence of H3.3 accumulation in neurons, our data suggest that nucleosome composition in the brain is reorganized with age.
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Affiliation(s)
- Gilda Stefanelli
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Amber B Azam
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Brandon J Walters
- Department of Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G OA4, Canada
| | - Mark A Brimble
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Hematology, University College London Cancer Institute, London, WC1E 6BT, UK
| | - Caroline P Gettens
- Department of Chemistry and Biochemistry, Bates College, Lewiston, ME 04240, USA
| | | | - Hai-Ying M Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Andrew M Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Klotilda Narkaj
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Jeremy J Day
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Andrew J Kennedy
- Department of Chemistry and Biochemistry, Bates College, Lewiston, ME 04240, USA.
| | - Iva B Zovkic
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada.
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Saraulli D, Costanzi M, Mastrorilli V, Farioli-Vecchioli S. The Long Run: Neuroprotective Effects of Physical Exercise on Adult Neurogenesis from Youth to Old Age. Curr Neuropharmacol 2018; 15:519-533. [PMID: 27000776 PMCID: PMC5543673 DOI: 10.2174/1570159x14666160412150223] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 03/08/2016] [Accepted: 03/16/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The rapid lengthening of life expectancy has raised the problem of providing social programs to counteract the age-related cognitive decline in a growing number of older people. Physical activity stands among the most promising interventions aimed at brain wellbeing, because of its effective neuroprotective action and low social cost. The purpose of this review is to describe the neuroprotective role exerted by physical activity in different life stages. In particular, we focus on adult neurogenesis, a process which has proved being highly responsive to physical exercise and may represent a major factor of brain health over the lifespan. METHODS The most recent literature related to the subject has been reviewed. The text has been divided into three main sections, addressing the effects of physical exercise during childhood/ adolescence, adulthood and aging, respectively. For each one, the most relevant studies, carried out on both human participants and rodent models, have been described. RESULTS The data reviewed converge in indicating that physical activity exerts a positive effect on brain functioning throughout the lifespan. However, uncertainty remains about the magnitude of the effect and its biological underpinnings. Cellular and synaptic plasticity provided by adult neurogenesis are highly probable mediators, but the mechanism for their action has yet to be conclusively established. CONCLUSION Despite alternative mechanisms of action are currently debated, age-appropriate physical activity programs may constitute a large-scale, relatively inexpensive and powerful approach to dampen the individual and social impact of age-related cognitive decline.
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Affiliation(s)
- Daniele Saraulli
- Institute of Cell Biology and Neurobiology, National Research Council, & Fondazione S. Lucia, Rome. Italy
| | - Marco Costanzi
- Department of Human Sciences, LUMSA University, Rome. Italy
| | - Valentina Mastrorilli
- Institute of Cell Biology and Neurobiology, National Research Council, & Fondazione S. Lucia, Rome. Italy
| | - Stefano Farioli-Vecchioli
- Institute of Cell Biology and Neurobiology, National Research Council, Via del Fosso di Fiorano 64, 00143 Rome. Italy
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Abstract
Adult hippocampal neurogenesis (AHN) occurs in humans and every other mammalian species examined. Evidence that AHN is stimulated by a variety of treatments and behaviors with anxiolytic properties has sparked interest in harnessing AHN to treat anxiety disorders. However, relatively little is known about the mechanisms through which AHN modulates fear and anxiety. In this review, we consider evidence that AHN modulates fear and anxiety by altering the processing of and memory for traumatic experiences. Based on studies of the role of AHN in Pavlovian fear conditioning, we conclude that AHN modulates the consequences of aversive experience by influencing 1) the efficiency of hippocampus-dependent memory acquisition; 2) generalization of hippocampal fear memories; 3) long-term retention of hippocampal aversive memories; and 4) the nonassociative effects of acute aversive experience. The preclinical literature suggests that stimulation of AHN is likely to have therapeutically relevant consequences, including reduced generalization and long-term retention of aversive memories. However, the literature also identifies four caveats that must be addressed if AHN-based therapies are to achieve therapeutic benefits without significant side effects.
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Affiliation(s)
- Michael R Drew
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.
| | - Kylie A Huckleberry
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA
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Nees F, Griebe M, Ebert A, Ruttorf M, Gerber B, Wolf OT, Schad LR, Gass A, Szabo K. Implicit Learning in Transient Global Amnesia and the Role of Stress. Front Behav Neurosci 2016; 10:222. [PMID: 27909401 PMCID: PMC5112253 DOI: 10.3389/fnbeh.2016.00222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/31/2016] [Indexed: 01/24/2023] Open
Abstract
Transient global amnesia (TGA) is a disorder with reversible anterograde disturbance of explicit memory, frequently preceded by an emotionally or physically stressful event. By using magnetic resonance imaging (MRI) following an episode of TGA, small hippocampal lesions have been observed. Hence it has been postulated that the disorder is caused by the stress-related transient inhibition of memory formation in the hippocampus. In experimental studies, stress has been shown to affect both explicit and implicit learning—the latter defined as learning and memory processes that lack conscious awareness of the information acquired. To test the hypothesis that impairment of implicit learning in TGA is present and related to stress, we determined the effect of experimental exposure to stress on hippocampal activation patterns during an implicit learning paradigm in patients who suffered a recent TGA and healthy matched control subjects. We used a hippocampus-dependent aversive learning procedure (context conditioning with the phases habituation, acquisition, and extinction) during functional MRI following experimental stress exposure (socially evaluated cold pressor test). After a control procedure, controls showed successful learning during the acquisition phase, indicated by increased valence, arousal and contingency ratings to the paired (CON+) vs. the non-paired (CON−) conditioned stimulus, and successful extinction of the conditioned responses. Following stress, acquisition was still successful, however extinction was impaired with persistently increased contingency ratings. In contrast, TGA patients showed impairment of conditioned responses and insufficient extinction after the control procedure, indicated by a lack of significant differences between CON+ and CON− for valence and arousal ratings after the acquisition phase and by significantly increased contingency ratings after the extinction. After stress, aversive learning was not successful with non-significant ratings of all parameters. Concerning brain activation patterns after the control procedure, controls showed increased hippocampal response during acquisition after the control procedure. This was not seen after stress exposure. In TGA patients, we observed an increased response in the right ventral striatum in the acquisition phase following stress. These findings suggest that alterations in implicit learning processes, including impaired hippocampal and increased striatal responses, might play a role in TGA pathophysiology, partly related to acute stress.
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Affiliation(s)
- Frauke Nees
- Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University Mannheim, Germany
| | - Martin Griebe
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University Mannheim, Germany
| | - Anne Ebert
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University Mannheim, Germany
| | - Michaela Ruttorf
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany
| | - Benjamin Gerber
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University Mannheim, Germany
| | - Oliver T Wolf
- Department of Cognitive Psychology, Institute of Cognitive Neuroscience, Ruhr-University Bochum Bochum, Germany
| | - Lothar R Schad
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany
| | - Achim Gass
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University Mannheim, Germany
| | - Kristina Szabo
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University Mannheim, Germany
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Adult Hippocampal Neurogenesis Modulates Fear Learning through Associative and Nonassociative Mechanisms. J Neurosci 2015; 35:11330-45. [PMID: 26269640 DOI: 10.1523/jneurosci.0483-15.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Adult hippocampal neurogenesis is believed to support hippocampus-dependent learning and emotional regulation. These putative functions of adult neurogenesis have typically been studied in isolation, and little is known about how they interact to produce adaptive behavior. We used trace fear conditioning as a model system to elucidate mechanisms through which adult hippocampal neurogenesis modulates processing of aversive experience. To achieve a specific ablation of neurogenesis, we generated transgenic mice that express herpes simplex virus thymidine kinase specifically in neural progenitors and immature neurons. Intracerebroventricular injection of the prodrug ganciclovir caused a robust suppression of neurogenesis without suppressing gliogenesis. Neurogenesis ablation via this method or targeted x-irradiation caused an increase in context conditioning in trace but not delay fear conditioning. Data suggest that this phenotype represents opposing effects of neurogenesis ablation on associative and nonassociative components of fear learning. Arrest of neurogenesis sensitizes mice to nonassociative effects of fear conditioning, as evidenced by increased anxiety-like behavior in the open field after (but not in the absence of) fear conditioning. In addition, arrest of neurogenesis impairs associative trace conditioning, but this impairment can be masked by nonassociative fear. The results suggest that adult neurogenesis modulates emotional learning via two distinct but opposing mechanisms: it supports associative trace conditioning while also buffering against the generalized fear and anxiety caused by fear conditioning. SIGNIFICANCE STATEMENT The role of adult hippocampal neurogenesis in fear learning is controversial, with some studies suggesting neurogenesis is needed for aspects of fear learning and others suggesting it is dispensable. We generated transgenic mice in which neural progenitors can be selectively and inducibly ablated. Our data suggest that adult neurogenesis supports fear learning through two distinct mechanisms: it supports the ability to learn associations between traumatic events (unconditioned stimuli) and predictors (conditioned stimuli) while also buffering against nonassociative, anxiogenic effects of a traumatic experience. As a result, arrest of neurogenesis can enhance or impair learned fear depending on intensity of the traumatic experience and the extent to which it recruits associative versus nonassociative learning.
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7
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Costa V, Lugert S, Jagasia R. Role of adult hippocampal neurogenesis in cognition in physiology and disease: pharmacological targets and biomarkers. Handb Exp Pharmacol 2015; 228:99-155. [PMID: 25977081 DOI: 10.1007/978-3-319-16522-6_4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adult hippocampal neurogenesis is a remarkable form of brain structural plasticity by which new functional neurons are generated from adult neural stem cells/precursors. Although the precise role of this process remains elusive, adult hippocampal neurogenesis is important for learning and memory and it is affected in disease conditions associated with cognitive impairment, depression, and anxiety. Immature neurons in the adult brain exhibit an enhanced structural and synaptic plasticity during their maturation representing a unique population of neurons to mediate specific hippocampal function. Compelling preclinical evidence suggests that hippocampal neurogenesis is modulated by a broad range of physiological stimuli which are relevant in cognitive and emotional states. Moreover, multiple pharmacological interventions targeting cognition modulate adult hippocampal neurogenesis. In addition, recent genetic approaches have shown that promoting neurogenesis can positively modulate cognition associated with both physiology and disease. Thus the discovery of signaling pathways that enhance adult neurogenesis may lead to therapeutic strategies for improving memory loss due to aging or disease. This chapter endeavors to review the literature in the field, with particular focus on (1) the role of hippocampal neurogenesis in cognition in physiology and disease; (2) extrinsic and intrinsic signals that modulate hippocampal neurogenesis with a focus on pharmacological targets; and (3) efforts toward novel strategies pharmacologically targeting neurogenesis and identification of biomarkers of human neurogenesis.
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Affiliation(s)
- Veronica Costa
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases (NORD), Roche Innovation Center Basel, 124 Grenzacherstrasse, 4070, Basel, Switzerland
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8
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Hippocampal biomarkers of fear memory in an animal model of generalized anxiety disorder. Behav Brain Res 2014; 263:34-45. [DOI: 10.1016/j.bbr.2014.01.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 01/08/2014] [Accepted: 01/15/2014] [Indexed: 11/20/2022]
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10
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Ishii H, Shi Q, Fumino S, Konno S, Kinoshita S, Okabayashi S, Iida N, Kimura H, Tahara Y, Shibata S, Takanishi A. A novel method to develop an animal model of depression using a small mobile robot. Adv Robot 2013. [DOI: 10.1080/01691864.2013.752319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Although significant inconsistencies remain to be clarified, a role for neurogenesis in hippocampal functions, such as cognition, has been suggested by several reports. Yet, investigation in various species of mammals, including humans, revealed that rates of hippocampal neurogenesis are steadily declining with age. The very low levels of hippocampal neurogenesis persisting in the aged brain have been suspected to underlie the cognitive deficits observed in elderly. However, current evidence fails to support the hypothesis that decrease of neurogenesis along normal ageing leads to hippocampal dysfunction. Nevertheless, current studies are suggestive for a distinct role of hippocampal neurogenesis in young versus adult and old brain.
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Affiliation(s)
- Sébastien Couillard-Després
- Spinal Cord Injury and Tissue Regeneration Center Salzburg, Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Strubergasse 21, 5020, Salzburg, Austria,
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12
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New neurons in an aged brain. Behav Brain Res 2011; 227:497-507. [PMID: 22024433 DOI: 10.1016/j.bbr.2011.10.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 09/28/2011] [Accepted: 10/07/2011] [Indexed: 12/21/2022]
Abstract
Adult hippocampal neurogenesis is one of the most robust forms of synaptic plasticity in the nervous system and occurs throughout life. However, the rate of neurogenesis declines dramatically with age. Older animals have significantly less neural progenitor cell proliferation, neuronal differentiation, and newborn neuron survival compared to younger animals. Intrinsic properties of neural progenitor cells, such as gene transcription and telomerase activity, change with age, which may contribute to the observed decline in neurogenesis. In addition, age-related changes in the local cells of the neurogenic niche may no longer provide neural progenitor cells with the cell-cell contact and soluble cues necessary for hippocampal neurogenesis. Astrocytes, microglia, and endothelial cells undergo changes in morphology and signaling properties with age, altering the foundation of the neurogenic niche. While most studies indicate a correlation between decreased hippocampal neurogenesis and impaired performance in hippocampus-dependent cognitive tasks in aged mice, a few have demonstrated that young and aged mice are equivalent in their cognitive ability. Here, we summarize the different behavioral paradigms to test hippocampus-dependent cognition and the need to develop neurogenesis-dependent tasks.
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Kennard JA, Woodruff-Pak DS. Age sensitivity of behavioral tests and brain substrates of normal aging in mice. Front Aging Neurosci 2011; 3:9. [PMID: 21647305 PMCID: PMC3103996 DOI: 10.3389/fnagi.2011.00009] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/13/2011] [Indexed: 11/21/2022] Open
Abstract
Knowledge of age sensitivity, the capacity of a behavioral test to reliably detect age-related changes, has utility in the design of experiments to elucidate processes of normal aging. We review the application of these tests in studies of normal aging and compare and contrast the age sensitivity of the Barnes maze, eyeblink classical conditioning, fear conditioning, Morris water maze, and rotorod. These tests have all been implemented to assess normal age-related changes in learning and memory in rodents, which generalize in many cases to age-related changes in learning and memory in all mammals, including humans. Behavioral assessments are a valuable means to measure functional outcomes of neuroscientific studies of aging. Highlighted in this review are the attributes and limitations of these measures in mice in the context of age sensitivity and processes of brain aging. Attributes of these tests include reliability and validity as assessments of learning and memory, well-defined neural substrates, and sensitivity to neural and pharmacological manipulations and disruptions. These tests engage the hippocampus and/or the cerebellum, two structures centrally involved in learning and memory that undergo functional and anatomical changes in normal aging. A test that is less well represented in studies of normal aging, the context pre-exposure facilitation effect (CPFE) in fear conditioning, is described as a method to increase sensitivity of contextual fear conditioning to changes in the hippocampus. Recommendations for increasing the age sensitivity of all measures of normal aging in mice are included, as well as a discussion of the potential of the under-studied CPFE to advance understanding of subtle hippocampus-mediated phenomena.
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Affiliation(s)
- John A. Kennard
- Systems Neuroscience Laboratory, Neuroscience Program and Department of Psychology, Temple UniversityPhiladelphia, PA, USA
| | - Diana S. Woodruff-Pak
- Systems Neuroscience Laboratory, Neuroscience Program and Department of Psychology, Temple UniversityPhiladelphia, PA, USA
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Zhao HF, Li Q, Li Y. Long-term ginsenoside administration prevents memory loss in aged female C57BL/6J mice by modulating the redox status and up-regulating the plasticity-related proteins in hippocampus. Neuroscience 2011; 183:189-202. [PMID: 21463662 DOI: 10.1016/j.neuroscience.2011.03.048] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 03/22/2011] [Accepted: 03/22/2011] [Indexed: 12/13/2022]
Abstract
Memory impairment is considered to be one of the most prominent consequences of aging. Deterioration of memory begins in advance of old age in animals, including humans. The generation of reactive oxygen species (ROS) and/or free radicals-induced oxidative stress which is the major age-related changes, can lead to hippocampus damage and increase vulnerability to impaired learning and memory. Ginsenoside, the effective ingredient of ginseng, has been reported to have a neuron beneficial effect. In the present study, C57BL/6J mice aged 12 months were chronically treated with ginsenoside (three dose groups were given ginsenoside in drinking water for 8 months, the concentration of ginsenoside in drinking water was 0.028%, 0.056%, and 0.112% (w/v), respectively). Placebo-treated aged mice and young ones (4 months old) were used as controls. The efficacious effect of ginsenoside was manifested in the amelioration of memory impairment in aged mice by Morris water maze and step-down tests. Total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBARS) have been used as the biomarkers of oxidative stress. In ginsenoside treated groups, the activities of T-SOD and GSH-Px markedly increased, and the levels of TBARS and the content of protein carbonyl decreased significantly in serum and in hippocampus. The activation of lipofuscin formation, disruption or loss of cristae in mitochondria, the irregular nucleus and condensed chromatin laid against the nuclear membrane in pyramidal cells of hippocampal CA1 region, which are all related to oxidative stress, were also reduced after ginsenoside treatment. Processes of memory formation and functional plasticity are associated with postsynaptic density-95 (PSD-95), protein kinase Cγ subunit (PKCγ) and brain derived neurotrophic factor (BDNF). In the present study, we found that long-term ginsenoside treatment prevented age-related reductions of PSD-95, PKCγ, and BDNF in the hippocampus. These results demonstrated that long-term ginsenoside administration may prevent memory loss in aged C57BL/6J mice by modulating the redox status and up-regulating the plasticity-related proteins in hippocampus.
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Affiliation(s)
- H F Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi 030001, PR China
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Abstract
It has been well established that adult neurogenesis occurs throughout life in the subventricular (SVZ) and subgranular (SGZ) zones. However, the exact role of this type of brain plasticity is not yet clear. Many studies have shown that neurogenesis is involved in learning and memory. This has led to a hypothesis which suggests that impairment in memory during aging and neurodegenerative diseases such as Alzheimer's disease (AD) may involve abnormal neurogenesis. Indeed, during aging, there is an age-related decline in adult neurogenesis. This decline is mostly related to decreased proliferation, associated to decreased stimulation to proliferate in an aging brain. In AD, there is also evidence for decreased neurogenesis, that accompanies the neuronal loss characteristic of the disease. Interestingly in AD, there is increased proliferation, that may be caused by increasing amounts of soluble amyloid ß42-protein (Aβ₄₂). However, most of these new neurons die, and fibrillar Aβ₄₂ seems to be involved in generating an inappropriate environment for these neurons to mature. These findings open prospects for new strategies that can increase neurogenesis in normal or pathological processes in the aging brain, and by that decrease memory deficits.
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Pinnock SB, Blake AM, Platt NJ, Herbert J. The roles of BDNF, pCREB and Wnt3a in the latent period preceding activation of progenitor cell mitosis in the adult dentate gyrus by fluoxetine. PLoS One 2010; 5:e13652. [PMID: 21048974 PMCID: PMC2965105 DOI: 10.1371/journal.pone.0013652] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 10/04/2010] [Indexed: 02/04/2023] Open
Abstract
The formation of new neurons continues into adult life in the dentate gyrus of the rat hippocampus, as in many other species. Neurogenesis itself turns out to be highly labile, and is regulated by a number of factors. One of these is the serotoninergic system: treatment with drugs (such as the SSRI fluoxetine) markedly stimulates mitosis in the progenitor cells of the dentate gyrus. But this process has one remarkable feature: it takes at least 14 days of continuous treatment to be effective. This is despite the fact that the pharmacological action of fluoxetine occurs within an hour or so of first administration. This paper explores the role of BDNF in this process, using the effect of a Trk antagonist (K252a) on the labelling of progenitor cells with the mitosis marker Ki67 and the associated expression of pCREB and Wnt3a. These experiments show that (i) Fluoxetine increased Ki67 counts, as well as pCREB and Wnt3a expression in the dentate gyrus. The action of fluoxetine on the progenitor cells and on pCREB (but not Wnt3a) depends upon Trk receptor activation, since it was prevented by icv infusion of K252a. (ii) These receptors are required for both the first 7 days of fluoxetine action, during which no apparent change in progenitor mitosis occurs, as well as the second 7 days. Increased pCREB was always associated with progenitor cell mitosis, but Wnt3a expression may be necessary but not sufficient for increased progenitor cell proliferation. These results shed new light on the action of fluoxetine on neurogenesis in the adult dentate gyrus, and have both clinical and experimental interest.
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Affiliation(s)
- Scarlett B Pinnock
- Department of Physiology, Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
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Scharfman HE, McCloskey DP. Postnatal neurogenesis as a therapeutic target in temporal lobe epilepsy. Epilepsy Res 2009; 85:150-61. [PMID: 19369038 PMCID: PMC2713813 DOI: 10.1016/j.eplepsyres.2009.03.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 02/08/2009] [Accepted: 03/08/2009] [Indexed: 01/30/2023]
Abstract
After it was first identified that seizures increase neurogenesis in the adult brain of laboratory animals, the idea that postnatal neurogenesis may be involved in epilepsy became a topic of widespread interest. Since that time, two perspectives have developed. They primarily address temporal lobe epilepsy (TLE), because the data have either been based on animal models of TLE or patients with intractable TLE. The first perspective is that postnatal neurogenesis contributes to the predisposition for seizures in TLE. This premise is founded in the observations showing that there is a dramatic rise in neurogenesis after many types of insults or injuries which ultimately lead to TLE. As a result of the increase in neurogenesis, several changes in the dentate gyrus occur, and the net effect appears to be an increase in excitability. One of the changes is the formation of a population of granule cells (GCs) that mismigrate, leading to ectopic granule cells in the hilus (hilar EGCs) that exhibit periodic bursts of action potentials, and contribute to recurrent excitatory circuitry. Atypical dendrites also form on a subset of GCs, and project into the hilus (hilar basal dendrites). Hilar basal dendrites appear to preferentially increase the glutamatergic input relative to GABAergic synapses, increasing excitability of the subset of GCs that form hilar basal dendrites. The alternate view is that postnatal neurogenesis is a homeostatic mechanism in epilepsy that maintains normal excitability. This idea is supported by studies showing that some of the new GCs that are born after seizures, and migrate into the correct location, have normal or reduced excitability. Here we suggest that both perspectives may be important when considering a therapeutic strategy. It would seem advantageous to limit the numbers of mismigrating GCs and hilar basal dendrites, but maintain normal neurogenesis because it is potentially homeostatic. Maintaining normal neurogenesis is also important because it has been suggested that a decrease in dentate gyrus neurogenesis contributes to depression. It is challenging to design a strategy that would achieve these goals, and it is also difficult to propose how one could administer such a therapy prophylactically, that is, as an "antiepileptogenic" approach. Another issue to address is how a therapeutic intervention with these goals could be successful if it were administered after chronic seizures develop, when most patients seek therapy. Although difficult, a number of approaches are possible, and technical advances suggest that there are more on the horizon.
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Affiliation(s)
- Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute, 140 Old Orangeburg Rd., Bldg. 35, Orangeburg, NY 10962, United States.
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Zhao H, Li Q, Pei X, Zhang Z, Yang R, Wang J, Li Y. Long-term ginsenoside administration prevents memory impairment in aged C57BL/6J mice by up-regulating the synaptic plasticity-related proteins in hippocampus. Behav Brain Res 2009; 201:311-7. [PMID: 19428650 DOI: 10.1016/j.bbr.2009.03.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 02/27/2009] [Accepted: 03/04/2009] [Indexed: 01/10/2023]
Abstract
Memory impairment is considered to be one of the most prominent consequences of aging. Deterioration of memory begins in advance of old age in animals, including humans. Thus, it is extremely important to prevent memory decline for increasing healthy aging. Ginsenoside, the effective ingredient of ginseng, has been reported to have a neuron beneficial effect, but the preventive role on memory impairment and the underlying mechanisms have not been well determined. In the present study, C57BL/6J mice aged 12 months were chronically treated with ginsenoside 100mg/kg per day for 8 months. Placebo-treated aged mice, young and adult ones (4- and 8-month-old, respectively) were used as controls. The efficacious effect of ginsenoside was manifested in the amelioration of memory impairment in aged mice by Morris water maze and step-down tests. Compared with aged control group, the plasticity-related proteins including phospho-N-methyl-d-aspartate receptor1 (NMDAR1), phospho-calcium-calmodulin dependent kinase II (CaMK II), phospho-PKA catalytic beta subunit (PKA Cbeta), phospho-cAMP-response element binding protein (CREB) and brain derived neurotrophic factor (BDNF) in hippocampus significantly increased in ginsenoside treated group. These findings suggest that ginsenoside is effective on the prevention of age-related memory impairment, and the up-regulation of plasticity-related proteins in hippocampus may be one of the mechanisms.
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Affiliation(s)
- Haifeng Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Xueyuan Road 38, Beijing 100191, PR China
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Zhao H, Li Q, Zhang Z, Pei X, Wang J, Li Y. Long-term ginsenoside consumption prevents memory loss in aged SAMP8 mice by decreasing oxidative stress and up-regulating the plasticity-related proteins in hippocampus. Brain Res 2008; 1256:111-22. [PMID: 19133247 DOI: 10.1016/j.brainres.2008.12.031] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 12/02/2008] [Accepted: 12/09/2008] [Indexed: 12/17/2022]
Abstract
Ginsenoside, the effective component of ginseng, has been reported to have a neuron protective effect, but the preventive effect on Alzheimer's disease (AD) related memory loss and the underlying mechanisms have not been well determined. The senescence-accelerated mouse (SAM) is a useful model of AD-related memory impairment. In the present study, SAMP8 mice aged 4 months were chronically treated with ginsenoside (3 dose groups were given ginsenoside in drinking water for 7 months). The three groups were treated with ginsenoside 50, 100 and 200 mg/kg per day, respectively. Placebo-treated aged mice and young ones (4 months old) were used as controls. In addition, SAMR1 mice were used as "normal aging" control. The beneficial role of ginsenoside was manifested in the prevention of memory loss in aged SAMP8 mice. The optimal dose of ginsenoside is 100 or 200 mg/kg per day. In ginsenoside treated groups, the Abeta level markedly decreased in hippocampus and antioxidase level significantly increased in serum. In addition, the plasticity-related proteins in hippocampus significantly increased in the two ginsenoside treated groups. The plasticity-related proteins were checked in the present study including postsynaptic density-95 (PSD-95), phosphor-N-methyl-D-aspartate receptor 1 (p-NMDAR1), phospho-calcium-calmodulin dependent kinase II (p-CaMKII), phospho-protein kinase A Catalyticbeta subunit (p-PKA Cbeta) and protein kinase Cgamma subunit (PKCgamma), phospho-CREB (p-CREB) and brain derived neurotrophic factor (BDNF) etc. These findings suggest that the increase of antioxidation and up-regulation of plasticity-related proteins in hippocampus may be one of the mechanisms of ginsenoside on the memory loss prevention in aged SAMP8 mice.
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Affiliation(s)
- Haifeng Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100083, PR China
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Drapeau E, Nora Abrous D. Stem cell review series: role of neurogenesis in age-related memory disorders. Aging Cell 2008; 7:569-89. [PMID: 18221417 PMCID: PMC2990912 DOI: 10.1111/j.1474-9726.2008.00369.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2007] [Indexed: 02/06/2023] Open
Abstract
Neuroplasticity is characterized by growth and branching of dendrites, remodeling of synaptic contacts, and neurogenesis, thus allowing the brain to adapt to changes over time. It is maintained in adulthood but strongly repressed during aging. An age-related decline in neurogenesis is particularly pronounced in the two adult neurogenic areas, the subventricular zone and the dentate gyrus. This age-related decline seems to be attributable mainly to limited proliferation, associated with an age-dependent increase in quiescence and/or a lengthening of the cell cycle, and is closely dependent on environmental changes. Indeed, when triggered by appropriate signals, neurogenesis can be reactivated in senescent brains, thus confirming the idea that the age-related decrease in new neuron production is not an irreversible, cell-intrinsic process. The coevolution of neurogenesis and age-related memory deficits--especially regarding spatial memory--during senescence supports the idea that new neurons in the adult brain participate in memory processing, and that a reduction in the ability to generate new neurons contributes to the appearance of memory deficits with advanced age. Furthermore, the age-related changes in hippocampal plasticity and function are under environmental influences that can favor successful or pathological aging. A better understanding of the mechanisms that regulate neurogenesis is necessary to develop new therapeutic tools to cure or prevent the development of memory disorders that may appear during the course of aging in some individuals.
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Affiliation(s)
- Elodie Drapeau
- Doetsch's Laboratory, Columbia University, Department of PathologyP&S 14-511, 630 W 168th Street, New York, NY 10032, USA
| | - Djoher Nora Abrous
- INSERM U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2Bordeaux Cedex 33077, France
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Wojtowicz JM, Askew ML, Winocur G. The effects of running and of inhibiting adult neurogenesis on learning and memory in rats. Eur J Neurosci 2008; 27:1494-502. [DOI: 10.1111/j.1460-9568.2008.06128.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Diminished adult neurogenesis in the marmoset brain precedes old age. Proc Natl Acad Sci U S A 2007; 104:17169-73. [PMID: 17940008 DOI: 10.1073/pnas.0708228104] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
With aging there is a decline in the number of newly generated neurons in the dentate gyrus of the hippocampus. In rodents and tree shrews, this age-related decrease in neurogenesis is evident long before the animals become aged. No previous studies have investigated whether primates exhibit a similar decline in hippocampal neurogenesis with aging. To investigate this possibility, young to middle aged adult common marmosets (Callithrix jacchus) were injected with BrdU and perfused 3 weeks later. The number of newly generated cells in the subgranular zone/granule cell layer of the dentate gyrus was significantly lower in older animals and decreased linearly with age. A similar age-related decline in new cells was observed in the subventricular zone but not in the hilar region of the dentate gyrus. These data demonstrate that a substantial decrease in neurogenesis occurs before the onset of old age in the adult marmoset brain, suggesting the possibility that similar alterations occur in the human brain.
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Ben Abdallah NMB, Slomianka L, Lipp HP. Reversible effect of X-irradiation on proliferation, neurogenesis, and cell death in the dentate gyrus of adult mice. Hippocampus 2007; 17:1230-40. [PMID: 17764075 DOI: 10.1002/hipo.20358] [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: 02/03/2023]
Abstract
Therapeutic cranial X-irradiation causes cognitive deficits in adult and pediatric patients, in particular, when the exposed area includes the medial temporal lobes. Effects on adult neurogenesis within the hippocampus may be related to such deficits. To investigate this relation, we irradiated the brain of young adult C57Bl/6j mice with a single dose of 4 Gy at a dose-rate of 27.5 cGy/min. We observed an approximately 80% decrease in the number of cells immunoreactive for the proliferation marker Ki67, 16 and 48 h after exposure, which was restored to control values after 1 week. The number of doublecortin- and NeuroD-immunoreactive cells of neuronal lineage was reduced by 60-70% up to 1 week after irradiation, but not after 1 month. The number of pyknotic cells increased approximately 2.5 fold after 16 h, decreased to approximately 50% of control numbers after 48 h and 1 week, and was again at normal levels after 1 month. Granule cell number did not differ between different groups and time points. There was no apparent activation of microglia or astrocytes. Our findings consist of an acute and reversible effect of X-irradiation on proliferation, neurogenesis, and cell death. Transient changes of neurogenesis may play a role in transient impairments of cognitive performance of patients exposed to X-irradiation. We present an experimental approach to temporarily alter adult hippocampal neurogenesis (AhN), allowing mechanistic investigations of AhN and its relevance to cognitive performances. The work also represents a step toward optimized radiotherapy schedules.
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