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Luo X, Dai M, Wang M, Wang X, Guo W. Functional heterogeneity of Wnt-responsive and Hedgehog-responsive neural stem cells in the murine adult hippocampus. Dev Cell 2023; 58:2545-2562.e6. [PMID: 37607545 DOI: 10.1016/j.devcel.2023.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/31/2023] [Accepted: 07/28/2023] [Indexed: 08/24/2023]
Abstract
Neural stem cells (NSCs) in the adult hippocampus are composed of multiple subpopulations. However, their origin and functional heterogeneity are still unclear. Here, we found that the contribution of murine Wnt-responsive (Axin2+) and Hedgehog-responsive (Gli1+) embryonic neural progenitors to adult NSCs started from early and late postnatal stages, respectively. Axin2+ adult NSCs were intended to actively proliferate, whereas Gli1+ adult NSCs were relatively quiescent and responsive to external stimuli. Moreover, Gli1+ NSC-derived adult-born neurons exhibited more complex dendritic arborization and connectivity than Axin2+ NSC-derived ones. Importantly, genetic cell ablation analysis identified that Axin2+ and Gli1+ adult NSCs were involved in hippocampus-dependent learning, but only Axin2+ adult NSCs were engaged in buffering stress responses and depressive behavior. Together, our study not only defined the heterogeneous multiple origins of adult NSCs but also advanced the concept that different subpopulations of adult NSCs may function differently.
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Affiliation(s)
- Xing Luo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China
| | - Min Dai
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China
| | - Min Wang
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiujie Wang
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China
| | - Weixiang Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China.
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2
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Amelchenko EM, Bezriadnov DV, Chekhov OA, Anokhin KV, Lazutkin AA, Enikolopov G. Age-related decline in cognitive flexibility is associated with the levels of hippocampal neurogenesis. Front Neurosci 2023; 17:1232670. [PMID: 37645372 PMCID: PMC10461065 DOI: 10.3389/fnins.2023.1232670] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/28/2023] [Indexed: 08/31/2023] Open
Abstract
Aging is associated with impairments in learning, memory, and cognitive flexibility, as well as a gradual decline in hippocampal neurogenesis. We investigated the performance of 6-and 14-month-old mice (considered mature adult and late middle age, respectively) in learning and memory tasks based on the Morris water maze (MWM) and determined their levels of preceding and current neurogenesis. While both age groups successfully performed in the spatial version of MWM (sMWM), the older mice were less efficient compared to the younger mice when presented with modified versions of the MWM that required a reassessment of the previously acquired experience. This was detected in the reversal version of MWM (rMWM) and was particularly evident in the context discrimination MWM (cdMWM), a novel task that required integrating various distal cues, local cues, and altered contexts and adjusting previously used search strategies. Older mice were impaired in several metrics that characterize rMWM and cdMWM, however, they showed improvement and narrowed the performance gap with the younger mice after additional training. Furthermore, we analyzed the adult-born mature and immature neurons in the hippocampal dentate gyrus and found a significant correlation between neurogenesis levels in individual mice and their performance in the tasks demanding cognitive flexibility. These results provide a detailed description of the age-related changes in learning and memory and underscore the importance of hippocampal neurogenesis in supporting cognitive flexibility.
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Affiliation(s)
- Evgeny M. Amelchenko
- Center for Developmental Genetics, Stony Brook, NY, United States
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States
| | | | - Olga A. Chekhov
- Center for Developmental Genetics, Stony Brook, NY, United States
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States
| | - Konstantin V. Anokhin
- P.K. Anokhin Research Institute of Normal Physiology RAS, Moscow, Russia
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, Moscow, Russia
| | - Alexander A. Lazutkin
- Center for Developmental Genetics, Stony Brook, NY, United States
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, Russia
| | - Grigori Enikolopov
- Center for Developmental Genetics, Stony Brook, NY, United States
- Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States
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3
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Gulyaeva NV. Glucocorticoids Orchestrate Adult Hippocampal Plasticity: Growth Points and Translational Aspects. Biochemistry (Mosc) 2023; 88:565-589. [PMID: 37331704 DOI: 10.1134/s0006297923050012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 06/20/2023]
Abstract
The review analyzes modern concepts about the control of various mechanisms of the hippocampal neuroplasticity in adult mammals and humans by glucocorticoids. Glucocorticoid hormones ensure the coordinated functioning of key components and mechanisms of hippocampal plasticity: neurogenesis, glutamatergic neurotransmission, microglia and astrocytes, systems of neurotrophic factors, neuroinflammation, proteases, metabolic hormones, neurosteroids. Regulatory mechanisms are diverse; along with the direct action of glucocorticoids through their receptors, there are conciliated glucocorticoid-dependent effects, as well as numerous interactions between various systems and components. Despite the fact that many connections in this complex regulatory scheme have not yet been established, the study of the factors and mechanisms considered in the work forms growth points in the field of glucocorticoid-regulated processes in the brain and primarily in the hippocampus. These studies are fundamentally important for the translation into the clinic and the potential treatment/prevention of common diseases of the emotional and cognitive spheres and respective comorbid conditions.
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Affiliation(s)
- Natalia V Gulyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.
- Research and Clinical Center for Neuropsychiatry of Moscow Healthcare Department, Moscow, 115419, Russia
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Abstract
Adult neurogenesis, the process by which neurons are generated in certain areas of the adult brain, declines in an age-dependent manner and is one potential target for extending cognitive healthspan. Aging is a major risk factor for neurodegenerative diseases and, as lifespans are increasing, these health challenges are becoming more prevalent. An age-associated loss in neural stem cell number and/or activity could cause this decline in brain function, so interventions that reverse aging in stem cells might increase the human cognitive healthspan. In this review, we describe the involvement of adult neurogenesis in neurodegenerative diseases and address the molecular mechanistic aspects of neurogenesis that involve some of the key aggregation-prone proteins in the brain (i.e., tau, Aβ, α-synuclein, …). We summarize the research pertaining to interventions that increase neurogenesis and regulate known targets in aging research, such as mTOR and sirtuins. Lastly, we share our outlook on restoring the levels of neurogenesis to physiological levels in elderly individuals and those with neurodegeneration. We suggest that modulating neurogenesis represents a potential target for interventions that could help in the fight against neurodegeneration and cognitive decline.
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Affiliation(s)
- Luka Culig
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Xixia Chu
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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Sep MSC, Vellinga M, Sarabdjitsingh RA, Joëls M. The rodent object-in-context task: A systematic review and meta-analysis of important variables. PLoS One 2021; 16:e0249102. [PMID: 34270575 PMCID: PMC8284613 DOI: 10.1371/journal.pone.0249102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/24/2021] [Indexed: 12/15/2022] Open
Abstract
Environmental information plays an important role in remembering events. Information about stable aspects of the environment (here referred to as 'context') and the event are combined by the hippocampal system and stored as context-dependent memory. In rodents (such as rats and mice), context-dependent memory is often investigated with the object-in-context task. However, the implementation and interpretation of this task varies considerably across studies. This variation hampers the comparison between studies and-for those who design a new experiment or carry out pilot experiments-the estimation of whether observed behavior is within the expected range. Also, it is currently unclear which of the variables critically influence the outcome of the task. To address these issues, we carried out a preregistered systematic review (PROSPERO CRD42020191340) and provide an up-to-date overview of the animal-, task-, and protocol-related variations in the object-in-context task for rodents. Using a data-driven explorative meta-analysis we next identified critical factors influencing the outcome of this task, such as sex, testbox size and the delay between the learning trials. Based on these observations we provide recommendations on sex, strain, prior arousal, context (size, walls, shape, etc.) and timing (habituation, learning, and memory phase) to create more consensus in the set-up, procedure, and interpretation of the object-in-context task for rodents. This could contribute to a more robust and evidence-based design in future animal experiments.
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Affiliation(s)
- Milou S. C. Sep
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
- Brain Research and Innovation Centre, Ministry of Defence, Utrecht, The Netherlands
| | - Marijn Vellinga
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - R. Angela Sarabdjitsingh
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Marian Joëls
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Ibrayeva A, Bay M, Pu E, Jörg DJ, Peng L, Jun H, Zhang N, Aaron D, Lin C, Resler G, Hidalgo A, Jang MH, Simons BD, Bonaguidi MA. Early stem cell aging in the mature brain. Cell Stem Cell 2021; 28:955-966.e7. [PMID: 33848469 PMCID: PMC10069280 DOI: 10.1016/j.stem.2021.03.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/19/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022]
Abstract
Stem cell dysfunction drives many age-related disorders. Identifying mechanisms that initially compromise stem cell behavior represent early targets to promote tissue function later in life. Here, we pinpoint multiple factors that disrupt neural stem cell (NSC) behavior in the adult hippocampus. Clonal tracing showed that NSCs exhibit asynchronous depletion by identifying short-term NSCs (ST-NSCs) and long-term NSCs (LT-NSCs). ST-NSCs divide rapidly to generate neurons and deplete in the young brain. Meanwhile, multipotent LT-NSCs are maintained for months but are pushed out of homeostasis by lengthening quiescence. Single-cell transcriptome analysis of deep NSC quiescence revealed several hallmarks of molecular aging in the mature brain and identified tyrosine-protein kinase Abl1 as an NSC aging factor. Treatment with the Abl inhibitor imatinib increased NSC activation without impairing NSC maintenance in the middle-aged brain. Our study indicates that hippocampal NSCs are particularly vulnerable and adaptable to cellular aging.
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Affiliation(s)
- Albina Ibrayeva
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; USC Davis School - Buck Institute Graduate Program in the Biology of Aging, University of Southern California, Los Angeles, CA 90033, USA
| | - Maxwell Bay
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; Neuroscience Graduate Program, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Elbert Pu
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - David J Jörg
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK; Gurdon Institute, University of Cambridge, Cambridge CB3 0HE, UK
| | - Lei Peng
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; Neuroscience Graduate Program, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Heechul Jun
- Department of Neurological Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Naibo Zhang
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Daniel Aaron
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Congrui Lin
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Galen Resler
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Axel Hidalgo
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Mi-Hyeon Jang
- Department of Neurological Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Benjamin D Simons
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK; Gurdon Institute, University of Cambridge, Cambridge CB3 0HE, UK
| | - Michael A Bonaguidi
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research at USC, University of Southern California, Los Angeles, CA 90033, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; USC Davis School - Buck Institute Graduate Program in the Biology of Aging, University of Southern California, Los Angeles, CA 90033, USA; Neuroscience Graduate Program, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA; Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90033, USA; Davis School of Gerontology, University of Southern California, Los Angeles, CA 90033, USA.
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7
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Peall IW, Okolicsanyi RK, Griffiths LR, Haupt LM. Three-Dimensional Human Neural Stem Cell Models to Mimic Heparan Sulfate Proteoglycans and the Neural Niche. Semin Thromb Hemost 2021; 47:308-315. [PMID: 33794554 DOI: 10.1055/s-0041-1724117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heparan sulfate proteoglycans (HSPGs) are a diverse family of polysaccharides, consisting of a core protein with glycosaminoglycan (GAG) side chains attached. The heterogeneous GAG side-chain carbohydrates consist of repeating disaccharides, with each side chain possessing a specific sulfation pattern. It is the variable sulfation pattern that allows HSPGs to interact with numerous ligands including growth factors, cytokines, chemokines, morphogens, extracellular matrix (ECM) glycoproteins, collagens, enzymes, and lipases. HSPGs are classified according to their localization within an individual cell, and include the membrane bound syndecans (SDCs) and glypicans (GPCs), with perlecan, agrin, and type-XVIII collagen secreted into the ECM. The stem cell niche is defined as the environment that circumscribes stem cells when they are in their naïve state, and includes the ECM, which provides a complex contribution to various biological processes during development and throughout life. These contributions include facilitating cell adhesion, proliferation, migration, differentiation, specification, and cell survival. In contrast, HSPGs play an anticoagulant role in thrombosis through being present on the luminal surface of cells, while also playing roles in the stimulation and inhibition of angiogenesis, highlighting their varied and systemic roles in cellular control. To fully understand the complexities of cell-cell and cell-matrix interactions, three-dimensional (3D) models such as hydrogels offer researchers exciting opportunities, such as controllable 3D in vitro environments, that more readily mimic the in vivo/in situ microenvironment. This review examines our current knowledge of HSPGs in the stem cell niche, human stem cell models, and their role in the development of 3D models that mimic the in vivo neural ECM.
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Affiliation(s)
- Ian W Peall
- Genomics Research Centre, Stem Cell and Neurogenesis Group, Centre for Genomics and Personalised Health, School of Biomedical Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Rachel K Okolicsanyi
- Genomics Research Centre, Stem Cell and Neurogenesis Group, Centre for Genomics and Personalised Health, School of Biomedical Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Lyn R Griffiths
- Genomics Research Centre, Stem Cell and Neurogenesis Group, Centre for Genomics and Personalised Health, School of Biomedical Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Larisa M Haupt
- Genomics Research Centre, Stem Cell and Neurogenesis Group, Centre for Genomics and Personalised Health, School of Biomedical Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia
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Dewey CW, Rishniw M, Johnson PJ, Platt S, Robinson K, Sackman J, O'Donnell M. Canine cognitive dysfunction patients have reduced total hippocampal volume compared with aging control dogs: A comparative magnetic resonance imaging study. Open Vet J 2020; 10:438-442. [PMID: 33614439 PMCID: PMC7830179 DOI: 10.4314/ovj.v10i4.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
Background: Hippocampal atrophy is a key pathologic and magnetic resonance imaging (MRI) feature of human Alzheimer’s disease (AD). Hippocampal atrophy has not been documented via MRI in canine cognitive dysfunction (CCD), which is considered as the dog model of human AD. Aim: The purpose of this retrospective comparative volumetric MRI study was to compare total hippocampal volumes between successfully aging (control) dogs and dogs diagnosed with CCD. Methods: Mimics® software was used to derive total hippocampal volumes and total brain volumes from the MRI studies of 42 aging dogs (≥ 9 years): 16 dogs diagnosed with CCD and 26 successfully aging controls. Hippocampal volumes were normalized to total brain volume and these values were compared between groups using Mann–Whitney U tests. Results: Total hippocampal volume normalized to total brain volume was significantly less for CCD patients compared with control dogs (p = 0.04). Conclusion: The results of this study suggest that – similar to human AD – hippocampal atrophy is a pathological feature of CCD. This finding has potential importance for both investigating disease mechanisms related to dementia as well as future hippocampal-targeted therapies.
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Affiliation(s)
- Curtis Wells Dewey
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.,Department of Surgery, Long Island Veterinary Specialists, Plainview, NY, USA.,Rochester Veterinary Specialists and Emergency Services, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Mark Rishniw
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Philippa J Johnson
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Simon Platt
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Kelsey Robinson
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Joseph Sackman
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.,Department of Surgery, Long Island Veterinary Specialists, Plainview, NY, USA.,Rochester Veterinary Specialists and Emergency Services, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Marissa O'Donnell
- Department of Surgery, Long Island Veterinary Specialists, Plainview, NY, USA
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Abstract
There has been interest in the function of adult neurogenesis since its discovery, by Joseph Altman, nearly 60 years ago. While controversy curtailed follow up studies, in the 1990s a second wave of research validated many of Altman's original claims and revealed that factors such as stress and environmental stimulation altered the production of new neurons in the hippocampus. However, only with the advent of tools for manipulating neurogenesis did it become possible to perform causal tests of the function of newborn neurons. Here, we identify approximately 100 studies in which adult neurogenesis was manipulated to study its function. A majority of these studies demonstrate functions for adult neurogenesis in classic hippocampal behaviors such as context learning and spatial memory, as well as emotional behaviors related to stress, anxiety and depression. However, a closer look reveals a number of other, arguably understudied, functions in decision making, temporal association memory, and addiction. In this special issue, we present 16 new studies and review articles that continue to address and clarify the function of adult neurogenesis in behaviors as diverse as memory formation, consolidation and forgetting, pattern separation and discrimination behaviors, addiction, and attention. Reviews of stem cell dynamics and regenerative properties provide insights into the mechanisms by which neurogenesis may be controlled to offset age- and disease-related brain injury. Finally, translation-oriented reviews identify next steps for minimizing the gap between discoveries made in animals and applications for human health. The articles in this issue synthesize and extend what we have learned in the last half century of functional neurogenesis research and identify themes that will define its future.
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Affiliation(s)
- Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada.
| | - Michael R Drew
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas, 78712, USA
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Huguet G, Kádár E, Serrano N, Tapias-Espinosa C, García-Brito S, Morgado-Bernal I, Aldavert-Vera L, Segura-Torres P. Rewarding deep brain stimulation at the medial forebrain bundle favours avoidance conditioned response in a remote memory test, hinders extinction and increases neurogenesis. Behav Brain Res 2020; 378:112308. [PMID: 31629001 DOI: 10.1016/j.bbr.2019.112308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/15/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
Intracranial Self-Stimulation (ICSS) at the medial forebrain bundle consistently facilitates learning and memory in rats when administered post-training or when administered non-concurrent to training, but its scope regarding remote memory has not yet been studied. The present work aims to test whether the combination of these two forms of ICSS administration can cause a greater persistence of the facilitating effect on remote retention and affect neurogenesis in the dentate gyrus (DG) of the hippocampus. Rats were trained in active avoidance conditioning and tested in two retention sessions (10 and 90 days) and later extinction. Subjects received an ICSS session after each of the five avoidance acquisition sessions (post-training treatment) and half of them also received ten additional ICSS sessions during the rest period between retention tests (non-concurrent treatment). All the stimulated groups showed a higher performance in acquisition and retention sessions, but only the rats receiving both ICSS treatments showed greater resistance to extinction. Remarkably, at seven months, rats receiving the non-concurrent ICSS treatment had a greater number of DCX-positive cells in the DG as well as a higher amount of new-born cells within the granular layer compared to rats that did not receive this additional ICSS treatment. Our present findings significantly extend the temporal window of the facilitating effect of ICSS on active avoidance and demonstrate a neurogenic effect of rewarding medial forebrain bundle stimulation.
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