1
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Frame AK, Sinka JL, Courchesne M, Muhammad RA, Grahovac-Nemeth S, Bernards MA, Bartha R, Cumming RC. Altered neuronal lactate dehydrogenase A expression affects cognition in a sex- and age-dependent manner. iScience 2024; 27:110342. [PMID: 39055955 PMCID: PMC11269950 DOI: 10.1016/j.isci.2024.110342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/15/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
The astrocyte-neuron lactate shuttle (ANLS) model posits that astrocyte-generated lactate is transported to neurons to fuel memory processes. However, neurons express high levels of lactate dehydrogenase A (LDHA), the rate-limiting enzyme of lactate production, suggesting a cognitive role for neuronally generated lactate. It was hypothesized that lactate metabolism in neurons is critical for learning and memory. Here transgenic mice were generated to conditionally induce or knockout (KO) the Ldha gene in CNS neurons of adult mice. High pattern separation memory was enhanced by neuronal Ldha induction in young females, and by neuronal Ldha KO in aged females. In older mice, Ldha induction caused cognitive deficits whereas Ldha KO caused cognitive improvements. Genotype-associated cognitive changes were often only observed in one sex or oppositely in males and females. Thus, neuronal-generated lactate has sex-specific cognitive effects, is largely indispensable at young age, and may be detrimental to learning and memory with aging.
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Affiliation(s)
- Ariel K. Frame
- Department of Biology, Western University, London, ON N6A 5B7, Canada
| | - Jessica L. Sinka
- Department of Biology, Western University, London, ON N6A 5B7, Canada
| | - Marc Courchesne
- Department of Biology, Western University, London, ON N6A 5B7, Canada
| | | | | | - Mark A. Bernards
- Department of Biology, Western University, London, ON N6A 5B7, Canada
| | - Robert Bartha
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, Canada
| | - Robert C. Cumming
- Department of Biology, Western University, London, ON N6A 5B7, Canada
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2
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Rasetto NB, Giacomini D, Berardino AA, Waichman TV, Beckel MS, Di Bella DJ, Brown J, Davies-Sala MG, Gerhardinger C, Lie DC, Arlotta P, Chernomoretz A, Schinder AF. Transcriptional dynamics orchestrating the development and integration of neurons born in the adult hippocampus. SCIENCE ADVANCES 2024; 10:eadp6039. [PMID: 39028813 PMCID: PMC11259177 DOI: 10.1126/sciadv.adp6039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 06/13/2024] [Indexed: 07/21/2024]
Abstract
The adult hippocampus generates new granule cells (aGCs) with functional capabilities that convey unique forms of plasticity to the preexisting circuits. While early differentiation of adult radial glia-like cells (RGLs) has been studied extensively, the molecular mechanisms guiding the maturation of postmitotic neurons remain unknown. Here, we used a precise birthdating strategy to study aGC differentiation using single-nuclei RNA sequencing. Transcriptional profiling revealed a continuous trajectory from RGLs to mature aGCs, with multiple immature stages bearing increasing levels of effector genes supporting growth, excitability, and synaptogenesis. Analysis of differential gene expression, pseudo-time trajectory, and transcription factors (TFs) revealed critical transitions defining four cellular states: quiescent RGLs, proliferative progenitors, immature aGCs, and mature aGCs. Becoming mature aGCs involved a transcriptional switch that shuts down pathways promoting cell growth, such SoxC TFs, to activate programs that likely control neuronal homeostasis. aGCs overexpressing Sox4 or Sox11 remained immature. Our results unveil precise molecular mechanisms driving adult RGLs through the pathway of neuronal differentiation.
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Affiliation(s)
- Natalí B. Rasetto
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Neuronal Plasticity, Leloir Institute, Buenos Aires, Argentina
| | - Damiana Giacomini
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Neuronal Plasticity, Leloir Institute, Buenos Aires, Argentina
| | - Ariel A. Berardino
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Integrative Systems Biology, Leloir Institute, Buenos Aires, Argentina
| | - Tomás Vega Waichman
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Integrative Systems Biology, Leloir Institute, Buenos Aires, Argentina
| | - Maximiliano S. Beckel
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Integrative Systems Biology, Leloir Institute, Buenos Aires, Argentina
| | - Daniela J. Di Bella
- Department of Stem Cells and Regenerative Biology, Harvard University and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Juliana Brown
- Department of Stem Cells and Regenerative Biology, Harvard University and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - M. Georgina Davies-Sala
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Neuronal Plasticity, Leloir Institute, Buenos Aires, Argentina
| | - Chiara Gerhardinger
- Department of Stem Cells and Regenerative Biology, Harvard University and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Dieter Chichung Lie
- Institute of Biochemistry, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Paola Arlotta
- Department of Stem Cells and Regenerative Biology, Harvard University and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ariel Chernomoretz
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Integrative Systems Biology, Leloir Institute, Buenos Aires, Argentina
- University of Buenos Aires, School of Science, Phys Dept and INFINA (CONICET-UBA), Buenos Aires, Argentina
| | - Alejandro F. Schinder
- Instituto de Investigaciones Biomédicas de Buenos Aires (IIBBA) – CONICET, Buenos Aires, Argentina
- Laboratory of Neuronal Plasticity, Leloir Institute, Buenos Aires, Argentina
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3
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Mihailovich M, Germain PL, Shyti R, Pozzi D, Noberini R, Liu Y, Aprile D, Tenderini E, Troglio F, Trattaro S, Fabris S, Ciptasari U, Rigoli MT, Caporale N, D’Agostino G, Mirabella F, Vitriolo A, Capocefalo D, Skaros A, Franchini AV, Ricciardi S, Biunno I, Neri A, Nadif Kasri N, Bonaldi T, Aebersold R, Matteoli M, Testa G. Multiscale modeling uncovers 7q11.23 copy number variation-dependent changes in ribosomal biogenesis and neuronal maturation and excitability. J Clin Invest 2024; 134:e168982. [PMID: 39007270 PMCID: PMC11245157 DOI: 10.1172/jci168982] [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: 02/03/2023] [Accepted: 05/24/2024] [Indexed: 07/16/2024] Open
Abstract
Copy number variation (CNV) at 7q11.23 causes Williams-Beuren syndrome (WBS) and 7q microduplication syndrome (7Dup), neurodevelopmental disorders (NDDs) featuring intellectual disability accompanied by symmetrically opposite neurocognitive features. Although significant progress has been made in understanding the molecular mechanisms underlying 7q11.23-related pathophysiology, the propagation of CNV dosage across gene expression layers and their interplay remains elusive. Here we uncovered 7q11.23 dosage-dependent symmetrically opposite dynamics in neuronal differentiation and intrinsic excitability. By integrating transcriptomics, translatomics, and proteomics of patient-derived and isogenic induced neurons, we found that genes related to neuronal transmission follow 7q11.23 dosage and are transcriptionally controlled, while translational factors and ribosomal genes are posttranscriptionally buffered. Consistently, we found phosphorylated RPS6 (p-RPS6) downregulated in WBS and upregulated in 7Dup. Surprisingly, p-4EBP was changed in the opposite direction, reflecting dosage-specific changes in total 4EBP levels. This highlights different dosage-sensitive dyregulations of the mTOR pathway as well as distinct roles of p-RPS6 and p-4EBP during neurogenesis. Our work demonstrates the importance of multiscale disease modeling across molecular and functional layers, uncovers the pathophysiological relevance of ribosomal biogenesis in a paradigmatic pair of NDDs, and uncouples the roles of p-RPS6 and p-4EBP as mechanistically actionable relays in NDDs.
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Affiliation(s)
- Marija Mihailovich
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
| | - Pierre-Luc Germain
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Computational Neurogenomics, D-HEST Institute for Neuroscience, Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Reinald Shyti
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
| | - Davide Pozzi
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- IRCCS Humanitas Research Hospital, Milan, Italy
| | | | - Yansheng Liu
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Davide Aprile
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | | | - Flavia Troglio
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Sebastiano Trattaro
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Sonia Fabris
- Hematology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Ummi Ciptasari
- Department of Cognitive Neurosciences, RadboudUmc, Donders Institute for Brain Cognition and Behaviour, Nijmegen, Netherlands
| | - Marco Tullio Rigoli
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Nicolò Caporale
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | | | | | - Alessandro Vitriolo
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Daniele Capocefalo
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Adrianos Skaros
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
| | | | - Sara Ricciardi
- Department of Biosciences, University of Milan, Milan, Italy
- National Institute of Molecular Genetics, Fondazione Romeo ed Enrica Invernizzi, Milan, Italy
| | - Ida Biunno
- Integrated Systems Engineering Srl, c/o OpenZone, Bresso, Milan, Italy
| | - Antonino Neri
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
- Hematology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nael Nadif Kasri
- Department of Cognitive Neurosciences, RadboudUmc, Donders Institute for Brain Cognition and Behaviour, Nijmegen, Netherlands
| | - Tiziana Bonaldi
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Rudolf Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Michela Matteoli
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- IRCCS Humanitas Research Hospital, Milan, Italy
| | - Giuseppe Testa
- European Institute of Oncology (IEO) IRCCS, Milan, Italy
- Human Technopole, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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4
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Blum Moyse L, Berry H. A coupled neural field model for the standard consolidation theory. J Theor Biol 2024; 588:111818. [PMID: 38621583 DOI: 10.1016/j.jtbi.2024.111818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 03/29/2024] [Accepted: 04/03/2024] [Indexed: 04/17/2024]
Abstract
The standard consolidation theory states that short-term memories located in the hippocampus enable the consolidation of long-term memories in the neocortex. In other words, the neocortex slowly learns long-term memories with a transient support of the hippocampus that quickly learns unstable memories. However, it is not clear yet what could be the neurobiological mechanisms underlying these differences in learning rates and memory time-scales. Here, we propose a novel modeling approach of the standard consolidation theory, that focuses on its potential neurobiological mechanisms. In addition to synaptic plasticity and spike frequency adaptation, our model incorporates adult neurogenesis in the dentate gyrus as well as the difference in size between the neocortex and the hippocampus, that we associate with distance-dependent synaptic plasticity. We also take into account the interconnected spatial structure of the involved brain areas, by incorporating the above neurobiological mechanisms in a coupled neural field framework, where each area is represented by a separate neural field with intra- and inter-area connections. To our knowledge, this is the first attempt to apply neural fields to this process. Using numerical simulations and mathematical analysis, we explore the short-term and long-term dynamics of the model upon alternance of phases of hippocampal replay and retrieval cue of an external input. This external input is encodable as a memory pattern in the form of a multiple bump attractor pattern in the individual neural fields. In the model, hippocampal memory patterns become encoded first, before neocortical ones, because of the smaller distances between the bumps of the hippocampal memory patterns. As a result, retrieval of the input pattern in the neocortex at short time-scales necessitates the additional input delivered by the memory pattern of the hippocampus. Neocortical memory patterns progressively consolidate at longer times, up to a point where their retrieval does not need the support of the hippocampus anymore. At longer times, perturbation of the hippocampal neural fields by neurogenesis erases the hippocampus pattern, leading to a final state where the memory pattern is exclusively evoked in the neocortex. Therefore, the dynamics of our model successfully reproduces the main features of the standard consolidation theory. This suggests that neurogenesis in the hippocampus and distance-dependent synaptic plasticity coupled to synaptic depression and spike frequency adaptation, are indeed critical neurobiological processes in memory consolidation.
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Affiliation(s)
- Lisa Blum Moyse
- LIRIS, CNRS UMR 5205, Villeurbanne, F-69621, France; AIstroSight, Inria, Hospices Civils de Lyon, Universite Claude Bernard Lyon 1, Villeurbanne, F-69603, France.
| | - Hugues Berry
- AIstroSight, Inria, Hospices Civils de Lyon, Universite Claude Bernard Lyon 1, Villeurbanne, F-69603, France.
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5
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Kochan SMV, Malo MC, Jevtic M, Jahn-Kelleter HM, Wani GA, Ndoci K, Pérez-Revuelta L, Gaedke F, Schäffner I, Lie DC, Schauss A, Bergami M. Enhanced mitochondrial fusion during a critical period of synaptic plasticity in adult-born neurons. Neuron 2024; 112:1997-2014.e6. [PMID: 38582081 DOI: 10.1016/j.neuron.2024.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 01/25/2024] [Accepted: 03/11/2024] [Indexed: 04/08/2024]
Abstract
Integration of new neurons into adult hippocampal circuits is a process coordinated by local and long-range synaptic inputs. To achieve stable integration and uniquely contribute to hippocampal function, immature neurons are endowed with a critical period of heightened synaptic plasticity, yet it remains unclear which mechanisms sustain this form of plasticity during neuronal maturation. We found that as new neurons enter their critical period, a transient surge in fusion dynamics stabilizes elongated mitochondrial morphologies in dendrites to fuel synaptic plasticity. Conditional ablation of fusion dynamics to prevent mitochondrial elongation selectively impaired spine plasticity and synaptic potentiation, disrupting neuronal competition for stable circuit integration, ultimately leading to decreased survival. Despite profuse mitochondrial fragmentation, manipulation of competition dynamics was sufficient to restore neuronal survival but left neurons poorly responsive to experience at the circuit level. Thus, by enabling synaptic plasticity during the critical period, mitochondrial fusion facilitates circuit remodeling by adult-born neurons.
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Affiliation(s)
- Sandra M V Kochan
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Meret Cepero Malo
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Milica Jevtic
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Hannah M Jahn-Kelleter
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Gulzar A Wani
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Kristiano Ndoci
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Laura Pérez-Revuelta
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Felix Gaedke
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Iris Schäffner
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dieter Chichung Lie
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Astrid Schauss
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Matteo Bergami
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine, 50931 Cologne, Germany; Institute of Genetics, University of Cologne, Cologne 50674, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany.
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6
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Arellano JI, Rakic P. Modelling adult neurogenesis in the aging rodent hippocampus: a midlife crisis. Front Neurosci 2024; 18:1416460. [PMID: 38887368 PMCID: PMC11181911 DOI: 10.3389/fnins.2024.1416460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 05/17/2024] [Indexed: 06/20/2024] Open
Abstract
Contrary to humans, adult hippocampal neurogenesis in rodents is not controversial. And in the last three decades, multiple studies in rodents have deemed adult neurogenesis essential for most hippocampal functions. The functional relevance of new neurons relies on their distinct physiological properties during their maturation before they become indistinguishable from mature granule cells. Most functional studies have used very young animals with robust neurogenesis. However, this trait declines dramatically with age, questioning its functional relevance in aging animals, a caveat that has been mentioned repeatedly, but rarely analyzed quantitatively. In this meta-analysis, we use data from published studies to determine the critical functional window of new neurons and to model their numbers across age in both mice and rats. Our model shows that new neurons with distinct functional profile represent about 3% of the total granule cells in young adult 3-month-old rodents, and their number decline following a power function to reach less than 1% in middle aged animals and less than 0.5% in old mice and rats. These low ratios pose an important logical and computational caveat to the proposed essential role of new neurons in the dentate gyrus, particularly in middle aged and old animals, a factor that needs to be adequately addressed when defining the relevance of adult neurogenesis in hippocampal function.
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Affiliation(s)
- Jon I. Arellano
- Department of Neuroscience, Yale University, New Haven, CT, United States
| | - Pasko Rakic
- Department of Neuroscience, Yale University, New Haven, CT, United States
- Kavli Institute for Neuroscience at Yale, Yale University, New Haven, CT, United States
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7
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Kennedy WM, Gonzalez JC, Lee H, Wadiche JI, Overstreet-Wadiche L. T-Type Ca 2+ Channels Mediate a Critical Period of Plasticity in Adult-Born Granule Cells. J Neurosci 2024; 44:e1503232024. [PMID: 38413230 PMCID: PMC11007310 DOI: 10.1523/jneurosci.1503-23.2024] [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: 08/08/2023] [Revised: 01/26/2024] [Accepted: 02/20/2024] [Indexed: 02/29/2024] Open
Abstract
Adult-born granule cells (abGCs) exhibit a transient period of elevated synaptic plasticity that plays an important role in hippocampal function. Various mechanisms have been implicated in this critical period for enhanced plasticity, including minimal GABAergic inhibition and high intrinsic excitability conferred by T-type Ca2+ channels. Here we assess the contribution of synaptic inhibition and intrinsic excitability to long-term potentiation (LTP) in abGCs of adult male and female mice using perforated patch recordings. We show that the timing of critical period plasticity is unaffected by intact GABAergic inhibition such that 4-6-week-old abGCs exhibit LTP that is absent by 8 weeks. Blocking GABAA receptors, or partial blockade of GABA release from PV and nNos-expressing interneurons by a µ-opioid receptor agonist, strongly enhances LTP in 4-week-old GCs, suggesting that minimal inhibition does not underlie critical period plasticity. Instead, the closure of the critical period coincides with a reduction in the contribution of T-type Ca2+ channels to intrinsic excitability, and a selective T-type Ca2+ channel antagonist prevents LTP in 4-week-old but not mature GCs. Interestingly, whole-cell recordings that facilitate T-type Ca2+ channel activity in mature GCs unmasks LTP (with inhibition intact) that is also sensitive to a T-type Ca2+ channel antagonist, suggesting T-type channel activity in mature GCs is suppressed by native intracellular signaling. Together these results show that abGCs use T-type Ca2+ channels to overcome inhibition, providing new insight into how high intrinsic excitability provides young abGCs a competitive advantage for experience-dependent synaptic plasticity.
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Affiliation(s)
- William M Kennedy
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jose Carlos Gonzalez
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Haeun Lee
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jacques I Wadiche
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Linda Overstreet-Wadiche
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
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8
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Rasetto NB, Giacomini D, Berardino AA, Waichman TV, Beckel MS, Di Bella DJ, Brown J, Davies-Sala MG, Gerhardinger C, Lie DC, Arlotta P, Chernomoretz A, Schinder AF. Transcriptional dynamics orchestrating the development and integration of neurons born in the adult hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.03.565477. [PMID: 38260428 PMCID: PMC10802403 DOI: 10.1101/2023.11.03.565477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The adult hippocampus generates new granule cells (aGCs) that exhibit distinct functional capabilities along development, conveying a unique form of plasticity to the preexisting circuits. While early differentiation of adult radial glia-like neural stem cells (RGL) has been studied extensively, the molecular mechanisms guiding the maturation of postmitotic neurons remain unknown. Here, we used a precise birthdating strategy to follow newborn aGCs along differentiation using single-nuclei RNA sequencing (snRNA-seq). Transcriptional profiling revealed a continuous trajectory from RGLs to mature aGCs, with multiple sequential immature stages bearing increasing levels of effector genes supporting growth, excitability and synaptogenesis. Remarkably, four discrete cellular states were defined by the expression of distinct sets of transcription factors (TFs): quiescent neural stem cells, proliferative progenitors, postmitotic immature aGCs, and mature aGCs. The transition from immature to mature aCGs involved a transcriptional switch that shutdown molecular cascades promoting cell growth, such as the SoxC family of TFs, to activate programs controlling neuronal homeostasis. Indeed, aGCs overexpressing Sox4 or Sox11 remained stalled at the immature state. Our results unveil precise molecular mechanisms driving adult neural stem cells through the pathway of neuronal differentiation.
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9
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Chang WL, Hen R. Adult Neurogenesis, Context Encoding, and Pattern Separation: A Pathway for Treating Overgeneralization. ADVANCES IN NEUROBIOLOGY 2024; 38:163-193. [PMID: 39008016 DOI: 10.1007/978-3-031-62983-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
In mammals, the subgranular zone of the dentate gyrus is one of two brain regions (with the subventricular zone of the olfactory bulb) that continues to generate new neurons throughout adulthood, a phenomenon known as adult hippocampal neurogenesis (AHN) (Eriksson et al., Nat Med 4:1313-1317, 1998; García-Verdugo et al., J Neurobiol 36:234-248, 1998). The integration of these new neurons into the dentate gyrus (DG) has implications for memory encoding, with unique firing and wiring properties of immature neurons that affect how the hippocampal network encodes and stores attributes of memory. In this chapter, we will describe the process of AHN and properties of adult-born cells as they integrate into the hippocampal circuit and mature. Then, we will discuss some methodological considerations before we review evidence for the role of AHN in two major processes supporting memory that are performed by the DG. First, we will discuss encoding of contextual information for episodic memories and how this is facilitated by AHN. Second, will discuss pattern separation, a major role of the DG that reduces interference for the formation of new memories. Finally, we will review clinical and translational considerations, suggesting that stimulation of AHN may help decrease overgeneralization-a common endophenotype of mood, anxiety, trauma-related, and age-related disorders.
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Affiliation(s)
- Wei-Li Chang
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY, USA
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY, USA
| | - Rene Hen
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY, USA.
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY, USA.
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10
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Furest Cataldo B, Yang L, Cabezas B, Ovetsky J, Vicario DS. Novel sound exposure drives dynamic changes in auditory lateralization that are associated with perceptual learning in zebra finches. Commun Biol 2023; 6:1205. [PMID: 38012325 PMCID: PMC10681987 DOI: 10.1038/s42003-023-05567-7] [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: 05/17/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
Songbirds provide a model for adult plasticity in the auditory cortex as a function of recent experience due to parallels with human auditory processing. As for speech processing in humans, activity in songbirds' higher auditory cortex (caudomedial nidopallium, NCM) is lateralized for complex vocalization sounds. However, in Zebra finches exposed to a novel heterospecific (canary) acoustic environment for 4-9 days, the typical pattern of right-lateralization is reversed. We now report that, in birds passively exposed to a novel heterospecific environment for extended periods (up to 21 days), the right-lateralized pattern of epidural auditory potentials first reverses transiently then returns to the typical pattern. Using acute, bilateral multi-unit electrophysiology, we confirm that this dynamic pattern occurs in NCM. Furthermore, extended exposure enhances discrimination for heterospecific stimuli. We conclude that lateralization is functionally labile and, when engaged by novel sensory experience, contributes to discrimination of novel stimuli that may be ethologically relevant. Future studies seek to determine whether, (1) the dynamicity of lateralized processes engaged by novel sensory experiences recurs with every novel challenge in the same organism; (2) the dynamic pattern extends to other cortical, thalamic or midbrain structures; and (3) the phenomenon generalizes across sensory modalities.
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Affiliation(s)
| | - Lillian Yang
- The City College of New York (CUNY), Physiology, Pharmacology and Neuroscience Department, New York, NY, 10031, USA
| | - Bryan Cabezas
- Rutgers University, Department of Psychology, Piscataway, NJ, 08854, USA
| | - Jonathan Ovetsky
- Rutgers University, Department of Psychology, Piscataway, NJ, 08854, USA
| | - David S Vicario
- Rutgers University, Department of Psychology, Piscataway, NJ, 08854, USA.
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11
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Wang R, Peterson Z, Balasubramanian N, Khan KM, Chimenti MS, Thedens D, Nickl-Jockschat T, Marcinkiewcz CA. Lateral Septal Circuits Govern Schizophrenia-Like Effects of Ketamine on Social Behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552372. [PMID: 37609170 PMCID: PMC10441349 DOI: 10.1101/2023.08.08.552372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Schizophrenia is marked by poor social functioning that can have a severe impact on quality of life and independence, but the underlying neural circuity is not well understood. Here we used a translational model of subanesthetic ketamine in mice to delineate neural pathways in the brain linked to social deficits in schizophrenia. Mice treated with chronic ketamine (30 mg/kg/day for 10 days) exhibit profound social and sensorimotor deficits as previously reported. Using three- dimensional c-Fos immunolabeling and volume imaging (iDISCO), we show that ketamine treatment resulted in hypoactivation of the lateral septum (LS) in response to social stimuli. Chemogenetic activation of the LS rescued social deficits after ketamine treatment, while chemogenetic inhibition of previously active populations in the LS (i.e. social engram neurons) recapitulated social deficits in ketamine-naïve mice. We then examined the translatome of LS social engram neurons and found that ketamine treatment dysregulated genes implicated in neuronal excitability and apoptosis, which may contribute to LS hypoactivation. We also identified 38 differentially expressed genes (DEGs) in common with human schizophrenia, including those involved in mitochondrial function, apoptosis, and neuroinflammatory pathways. Chemogenetic activation of LS social engram neurons induced downstream activity in the ventral part of the basolateral amygdala, subparafascicular nucleus of the thalamus, intercalated amygdalar nucleus, olfactory areas, and dentate gyrus, and it also reduces connectivity of the LS with the piriform cortex and caudate-putamen. In sum, schizophrenia-like social deficits may emerge via changes in the intrinsic excitability of a discrete subpopulation of LS neurons that serve as a central hub to coordinate social behavior via downstream projections to reward, fear extinction, motor and sensory processing regions of the brain.
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12
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Tan Z, Luikart BW. Toward a better understanding of PHTS heterogeneity: commentary on 'Cell-type specific deficits in PTEN-mutant cortical organoids converge on abnormal circuit activity'. Hum Mol Genet 2023; 32:2771-2772. [PMID: 37540221 PMCID: PMC11007393 DOI: 10.1093/hmg/ddad127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/17/2023] [Accepted: 08/01/2023] [Indexed: 08/05/2023] Open
Affiliation(s)
- Zhibing Tan
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
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13
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Arribas DM, Marin-Burgin A, Morelli LG. Adult-born granule cells improve stimulus encoding and discrimination in the dentate gyrus. eLife 2023; 12:e80250. [PMID: 37584478 PMCID: PMC10476965 DOI: 10.7554/elife.80250] [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: 05/13/2022] [Accepted: 08/15/2023] [Indexed: 08/17/2023] Open
Abstract
Heterogeneity plays an important role in diversifying neural responses to support brain function. Adult neurogenesis provides the dentate gyrus with a heterogeneous population of granule cells (GCs) that were born and developed their properties at different times. Immature GCs have distinct intrinsic and synaptic properties than mature GCs and are needed for correct encoding and discrimination in spatial tasks. How immature GCs enhance the encoding of information to support these functions is not well understood. Here, we record the responses to fluctuating current injections of GCs of different ages in mouse hippocampal slices to study how they encode stimuli. Immature GCs produce unreliable responses compared to mature GCs, exhibiting imprecise spike timings across repeated stimulation. We use a statistical model to describe the stimulus-response transformation performed by GCs of different ages. We fit this model to the data and obtain parameters that capture GCs' encoding properties. Parameter values from this fit reflect the maturational differences of the population and indicate that immature GCs perform a differential encoding of stimuli. To study how this age heterogeneity influences encoding by a population, we perform stimulus decoding using populations that contain GCs of different ages. We find that, despite their individual unreliability, immature GCs enhance the fidelity of the signal encoded by the population and improve the discrimination of similar time-dependent stimuli. Thus, the observed heterogeneity confers the population with enhanced encoding capabilities.
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Affiliation(s)
- Diego M Arribas
- Instituto de Investigacion en Biomedicina de Buenos Aires (IBioBA) – CONICET/Partner Institute of the Max Planck Society, Polo Cientifico TecnologicoBuenos AiresArgentina
| | - Antonia Marin-Burgin
- Instituto de Investigacion en Biomedicina de Buenos Aires (IBioBA) – CONICET/Partner Institute of the Max Planck Society, Polo Cientifico TecnologicoBuenos AiresArgentina
| | - Luis G Morelli
- Instituto de Investigacion en Biomedicina de Buenos Aires (IBioBA) – CONICET/Partner Institute of the Max Planck Society, Polo Cientifico TecnologicoBuenos AiresArgentina
- Departamento de Fisica, FCEyN UBA, Ciudad UniversitariaBuenos AiresArgentina
- Max Planck Institute for Molecular Physiology, Department of Systemic Cell BiologyDortmundGermany
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14
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Schneider M, Bird AD, Gidon A, Triesch J, Jedlicka P, Cuntz H. Biological complexity facilitates tuning of the neuronal parameter space. PLoS Comput Biol 2023; 19:e1011212. [PMID: 37399220 DOI: 10.1371/journal.pcbi.1011212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/24/2023] [Indexed: 07/05/2023] Open
Abstract
The electrical and computational properties of neurons in our brains are determined by a rich repertoire of membrane-spanning ion channels and elaborate dendritic trees. However, the precise reason for this inherent complexity remains unknown, given that simpler models with fewer ion channels are also able to functionally reproduce the behaviour of some neurons. Here, we stochastically varied the ion channel densities of a biophysically detailed dentate gyrus granule cell model to produce a large population of putative granule cells, comparing those with all 15 original ion channels to their reduced but functional counterparts containing only 5 ion channels. Strikingly, valid parameter combinations in the full models were dramatically more frequent at -6% vs. -1% in the simpler model. The full models were also more stable in the face of perturbations to channel expression levels. Scaling up the numbers of ion channels artificially in the reduced models recovered these advantages confirming the key contribution of the actual number of ion channel types. We conclude that the diversity of ion channels gives a neuron greater flexibility and robustness to achieve a target excitability.
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Affiliation(s)
- Marius Schneider
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with the Max Planck Society, Frankfurt am Main, Germany
- ICAR3R-Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen, Germany
- Faculty of Physics, Goethe University, Frankfurt/Main, Frankfurt am Main, Germany
| | - Alexander D Bird
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with the Max Planck Society, Frankfurt am Main, Germany
- ICAR3R-Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen, Germany
| | - Albert Gidon
- Institute for Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jochen Triesch
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
- Faculty of Physics, Goethe University, Frankfurt/Main, Frankfurt am Main, Germany
- Faculty of Computer Science and Mathematics, Goethe University, Frankfurt am Main, Germany
| | - Peter Jedlicka
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
- ICAR3R-Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen, Germany
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, Frankfurt am Main, Germany
| | - Hermann Cuntz
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with the Max Planck Society, Frankfurt am Main, Germany
- ICAR3R-Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen, Germany
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15
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Xiang G, Liu X, Wang J, Lu S, Yu M, Zhang Y, Sun B, Huang B, Lu XY, Li X, Zhang D. Peroxisome proliferator-activated receptor-α activation facilitates contextual fear extinction and modulates intrinsic excitability of dentate gyrus neurons. Transl Psychiatry 2023; 13:206. [PMID: 37322045 DOI: 10.1038/s41398-023-02496-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 05/06/2023] [Accepted: 05/30/2023] [Indexed: 06/17/2023] Open
Abstract
The dentate gyrus (DG) of the hippocampus encodes contextual information associated with fear, and cell activity in the DG is required for acquisition and extinction of contextual fear. However, the underlying molecular mechanisms are not fully understood. Here we show that mice deficient for peroxisome proliferator-activated receptor-α (PPARα) exhibited a slower rate of contextual fear extinction. Furthermore, selective deletion of PPARα in the DG attenuated, while activation of PPARα in the DG by local infusion of aspirin facilitated extinction of contextual fear. The intrinsic excitability of DG granule neurons was reduced by PPARα deficiency but increased by activation of PPARα with aspirin. Using RNA-Seq transcriptome we found that the transcription level of neuropeptide S receptor 1 (Npsr1) was tightly correlated with PPARα activation. Our results provide evidence that PPARα plays an important role in regulating DG neuronal excitability and contextual fear extinction.
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Affiliation(s)
- Guo Xiang
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250012, China
| | - Xia Liu
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
| | - Jiangong Wang
- Institute of Metabolic and Neuropsychiatric Disorders, Binzhou Medical University Hospital, Binzhou, 256600, China
| | - Shunshun Lu
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
| | - Meng Yu
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
| | - Yuhan Zhang
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250012, China
| | - Bin Sun
- National Glycoengineering Research Center, Shandong University, Jinan, 250012, China
| | - Bin Huang
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250012, China
| | - Xin-Yun Lu
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Xingang Li
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250012, China
| | - Di Zhang
- Department of Neurosurgery, Qilu Hospital and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, 250012, China.
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250012, China.
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16
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Kim Y, Kim S, Ho WK, Lee SH. Burst firing is required for induction of Hebbian LTP at lateral perforant path to hippocampal granule cell synapses. Mol Brain 2023; 16:45. [PMID: 37217996 DOI: 10.1186/s13041-023-01034-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
High frequency burst firing is critical in summation of back-propagating action potentials (APs) in dendrites, which may greatly depolarize dendritic membrane potential. The physiological significance of burst firings of hippocampal dentate GCs in synaptic plasticity remains unknown. We found that GCs with low input resistance could be categorized into regular-spiking (RS) and burst-spiking (BS) cells based on their initial firing frequency (Finit) upon somatic rheobase current injection, and investigated how two types of GCs differ in long-term potentiation (LTP) induced by high-frequency lateral perforant pathway (LPP) inputs. Induction of Hebbian LTP at LPP synapses required at least three postsynaptic APs at Finit higher than 100 Hz, which was met in BS but not in RS cells. The synaptically evoked burst firing was critically dependent on persistent Na+ current, which was larger in BS than RS cells. The Ca2+ source for Hebbian LTP at LPP synapses was primarily provided by L-type calcium channels. In contrast, Hebbian LTP at medial PP synapses was mediated by T-type calcium channels, and could be induced regardless of cell types or Finit of postsynaptic APs. These results suggest that intrinsic firing properties affect synaptically driven firing patterns, and that bursting behavior differentially affects Hebbian LTP mechanisms depending on the synaptic input pathway.
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Affiliation(s)
- Yoonsub Kim
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sooyun Kim
- Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Won-Kyung Ho
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Suk-Ho Lee
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, 103 Daehak-Ro, Jongno-Gu, 03080, Seoul, Republic of Korea.
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17
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Parylak SL, Qiu F, Linker SB, Gallina IS, Lim CK, Preciado D, McDonald AH, Zhou X, Gage FH. Neuronal activity-related transcription is blunted in immature compared to mature dentate granule cells. Hippocampus 2023; 33:412-423. [PMID: 36811254 PMCID: PMC10985790 DOI: 10.1002/hipo.23515] [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: 09/26/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
Immature dentate granule cells (DGCs) generated in the hippocampus during adulthood are believed to play a unique role in dentate gyrus (DG) function. Although immature DGCs have hyperexcitable membrane properties in vitro, the consequences of this hyperexcitability in vivo remain unclear. In particular, the relationship between experiences that activate the DG, such as exploration of a novel environment (NE), and downstream molecular processes that modify DG circuitry in response to cellular activation is unknown in this cell population. We first performed quantification of immediate early gene (IEG) proteins in immature (5-week-old) and mature (13-week-old) DGCs from mice exposed to a NE. Paradoxically, we observed lower IEG protein expression in hyperexcitable immature DGCs. We then isolated nuclei from active and inactive immature DGCs and performed single-nuclei RNA-Sequencing. Compared to mature nuclei collected from the same animal, immature DGC nuclei showed less activity-induced transcriptional change, even though they were classified as active based on expression of ARC protein. These results demonstrate that the coupling of spatial exploration, cellular activation, and transcriptional change differs between immature and mature DGCs, with blunted activity-induced changes in immature cells.
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Affiliation(s)
- Sarah L Parylak
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Fan Qiu
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Sara B Linker
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Iryna S Gallina
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Christina K Lim
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - David Preciado
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Aidan H McDonald
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Xavier Zhou
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
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18
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Kitchigina V, Shubina L. Oscillations in the dentate gyrus as a tool for the performance of the hippocampal functions: Healthy and epileptic brain. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110759. [PMID: 37003419 DOI: 10.1016/j.pnpbp.2023.110759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The dentate gyrus (DG) is part of the hippocampal formation and is essential for important cognitive processes such as navigation and memory. The oscillatory activity of the DG network is believed to play a critical role in cognition. DG circuits generate theta, beta, and gamma rhythms, which participate in the specific information processing performed by DG neurons. In the temporal lobe epilepsy (TLE), cognitive abilities are impaired, which may be due to drastic alterations in the DG structure and network activity during epileptogenesis. The theta rhythm and theta coherence are especially vulnerable in dentate circuits; disturbances in DG theta oscillations and their coherence may be responsible for general cognitive impairments observed during epileptogenesis. Some researchers suggested that the vulnerability of DG mossy cells is a key factor in the genesis of TLE, but others did not support this hypothesis. The aim of the review is not only to present the current state of the art in this field of research but to help pave the way for future investigations by highlighting the gaps in our knowledge to completely appreciate the role of DG rhythms in brain functions. Disturbances in oscillatory activity of the DG during TLE development may be a diagnostic marker in the treatment of this disease.
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Affiliation(s)
- Valentina Kitchigina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia.
| | - Liubov Shubina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
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19
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Vyleta NP, Snyder JS. Enhanced excitability but mature action potential waveforms at mossy fiber terminals of young, adult-born hippocampal neurons in mice. Commun Biol 2023; 6:290. [PMID: 36934174 PMCID: PMC10024705 DOI: 10.1038/s42003-023-04678-5] [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: 10/12/2022] [Accepted: 03/07/2023] [Indexed: 03/20/2023] Open
Abstract
Adult-born granule neurons pass through immature critical periods where they display enhanced somatic excitability and afferent plasticity, which is believed to endow them with unique roles in hippocampal learning and memory. Using patch clamp recordings in mouse hippocampal slices, here we show that young neuron hyper-excitability is also observed at presynaptic mossy fiber terminals onto CA3 pyramidal neurons. However, action potential waveforms mature faster in the bouton than in the soma, suggesting rapid efferent functionality during immature stages.
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Affiliation(s)
- Nicholas P Vyleta
- Department of Psychology, Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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20
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Timmermann A, Tascio D, Jabs R, Boehlen A, Domingos C, Skubal M, Huang W, Kirchhoff F, Henneberger C, Bilkei-Gorzo A, Seifert G, Steinhäuser C. Dysfunction of NG2 glial cells affects neuronal plasticity and behavior. Glia 2023; 71:1481-1501. [PMID: 36802096 DOI: 10.1002/glia.24352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 02/20/2023]
Abstract
NG2 glia represents a distinct type of macroglial cells in the CNS and is unique among glia because they receive synaptic input from neurons. They are abundantly present in white and gray matter. While the majority of white matter NG2 glia differentiates into oligodendrocytes, the physiological impact of gray matter NG2 glia and their synaptic input are still ill defined. Here, we asked whether dysfunctional NG2 glia affect neuronal signaling and behavior. We generated mice with inducible deletion of the K+ channel Kir4.1 in NG2 glia and performed comparative electrophysiological, immunohistochemical, molecular and behavioral analyses. Kir4.1 was deleted at postnatal day 23-26 (recombination efficiency about 75%) and mice were investigated 3-8 weeks later. Notably, these mice with dysfunctional NG2 glia demonstrated improved spatial memory as revealed by testing new object location recognition while working and social memory remained unaffected. Focussing on the hippocampus, we found that loss of Kir4.1 potentiated synaptic depolarizations of NG2 glia and stimulated the expression of myelin basic protein while proliferation and differentiation of hippocampal NG2 glia remained largely unaffected. Mice with targeted deletion of the K+ channel in NG2 glia showed impaired long-term potentiation at CA3-CA1 synapses, which could be fully rescued by extracellular application of a TrkB receptor agonist. Our data demonstrate that proper NG2 glia function is important for normal brain function and behavior.
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Affiliation(s)
- Aline Timmermann
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Dario Tascio
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Ronald Jabs
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Anne Boehlen
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Catia Domingos
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Magdalena Skubal
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Wenhui Huang
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Neurology, University College London, London, UK
| | - Andras Bilkei-Gorzo
- Institute of Molecular Psychiatry, Medical Faculty, University of Bonn, Bonn, Germany
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
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21
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Ash AM, Regele-Blasco E, Seib DR, Chahley E, Skelton PD, Luikart BW, Snyder JS. Adult-born neurons inhibit developmentally-born neurons during spatial learning. Neurobiol Learn Mem 2023; 198:107710. [PMID: 36572174 DOI: 10.1016/j.nlm.2022.107710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Ongoing neurogenesis in the dentate gyrus (DG) subregion of the hippocampus results in a heterogenous population of neurons. Immature adult-born neurons (ABNs) have physiological and anatomical properties that may give them a unique role in learning. For example, compared to older granule neurons, they have greater somatic excitability, which could facilitate their recruitment into memory traces. However, recruitment is also likely to depend on interactions with other DG neurons through processes such as lateral inhibition. Immature ABNs target inhibitory interneurons and, compared to older neurons, they receive less GABAergic inhibition. Thus, they may induce lateral inhibition of mature DG neurons while being less susceptible to inhibition themselves. To test this we used a chemogenetic approach to silence immature ABNs as rats learned a spatial water maze task, and measured activity (Fos expression) in ABNs and developmentally-born neurons (DBNs). A retrovirus expressing the inhibitory DREADD receptor, hM4Di, was injected into the dorsal DG of male rats at 6w to infect neurons born in adulthood. Animals were also injected with BrdU to label DBNs or ABNs. DBNs were significantly more active than immature 4-week-old ABNs. Silencing 4-week-old ABNs did not alter learning but it increased activity in DBNs. However, silencing ABNs did not affect activation in other ABNs within the DG. Silencing ABNs also did not alter Fos expression in parvalbumin- and somatostatin-expressing interneurons. Collectively, these results suggest that ABNs may directly inhibit DBN activity during hippocampal-dependent learning, which may be relevant for maintaining sparse hippocampal representations of experienced events.
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Affiliation(s)
- Alyssa M Ash
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Elena Regele-Blasco
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Désirée R Seib
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Erin Chahley
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Patrick D Skelton
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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22
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Fölsz O, Trouche S, Croset V. Adult-born neurons add flexibility to hippocampal memories. Front Neurosci 2023; 17:1128623. [PMID: 36875670 PMCID: PMC9975346 DOI: 10.3389/fnins.2023.1128623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
Although most neurons are generated embryonically, neurogenesis is maintained at low rates in specific brain areas throughout adulthood, including the dentate gyrus of the mammalian hippocampus. Episodic-like memories encoded in the hippocampus require the dentate gyrus to decorrelate similar experiences by generating distinct neuronal representations from overlapping inputs (pattern separation). Adult-born neurons integrating into the dentate gyrus circuit compete with resident mature cells for neuronal inputs and outputs, and recruit inhibitory circuits to limit hippocampal activity. They display transient hyperexcitability and hyperplasticity during maturation, making them more likely to be recruited by any given experience. Behavioral evidence suggests that adult-born neurons support pattern separation in the rodent dentate gyrus during encoding, and they have been proposed to provide a temporal stamp to memories encoded in close succession. The constant addition of neurons gradually degrades old connections, promoting generalization and ultimately forgetting of remote memories in the hippocampus. This makes space for new memories, preventing saturation and interference. Overall, a small population of adult-born neurons appears to make a unique contribution to hippocampal information encoding and removal. Although several inconsistencies regarding the functional relevance of neurogenesis remain, in this review we argue that immature neurons confer a unique form of transience on the dentate gyrus that complements synaptic plasticity to help animals flexibly adapt to changing environments.
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Affiliation(s)
- Orsolya Fölsz
- Department of Biosciences, Durham University, Durham, United Kingdom.,MSc in Neuroscience Programme, University of Oxford, Oxford, United Kingdom
| | - Stéphanie Trouche
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Vincent Croset
- Department of Biosciences, Durham University, Durham, United Kingdom
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23
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Tran LM, Santoro A, Liu L, Josselyn SA, Richards BA, Frankland PW. Adult neurogenesis acts as a neural regularizer. Proc Natl Acad Sci U S A 2022; 119:e2206704119. [PMID: 36322739 PMCID: PMC9659416 DOI: 10.1073/pnas.2206704119] [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] [Indexed: 01/09/2023] Open
Abstract
New neurons are continuously generated in the subgranular zone of the dentate gyrus throughout adulthood. These new neurons gradually integrate into hippocampal circuits, forming new naive synapses. Viewed from this perspective, these new neurons may represent a significant source of "wiring" noise in hippocampal networks. In machine learning, such noise injection is commonly used as a regularization technique. Regularization techniques help prevent overfitting training data and allow models to generalize learning to new, unseen data. Using a computational modeling approach, here we ask whether a neurogenesis-like process similarly acts as a regularizer, facilitating generalization in a category learning task. In a convolutional neural network (CNN) trained on the CIFAR-10 object recognition dataset, we modeled neurogenesis as a replacement/turnover mechanism, where weights for a randomly chosen small subset of hidden layer neurons were reinitialized to new values as the model learned to categorize 10 different classes of objects. We found that neurogenesis enhanced generalization on unseen test data compared to networks with no neurogenesis. Moreover, neurogenic networks either outperformed or performed similarly to networks with conventional noise injection (i.e., dropout, weight decay, and neural noise). These results suggest that neurogenesis can enhance generalization in hippocampal learning through noise injection, expanding on the roles that neurogenesis may have in cognition.
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Affiliation(s)
- Lina M. Tran
- aNeuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- bDepartment of Physiology, University of Toronto, Toronto, ON, Canada
- cVector Institute, Toronto, ON, Canada
| | | | - Lulu Liu
- aNeuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sheena A. Josselyn
- aNeuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- bDepartment of Physiology, University of Toronto, Toronto, ON, Canada
- eDepartment of Psychology, University of Toronto, Toronto, ON, Canada
- fInstitute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Blake A. Richards
- gDepartment of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- hSchool of Computer Science, McGill University, Montreal, QC, Canada
- iMila, Montreal, QC, Canada
- jLearning in Machines and Brains, Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Paul W. Frankland
- aNeuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- bDepartment of Physiology, University of Toronto, Toronto, ON, Canada
- eDepartment of Psychology, University of Toronto, Toronto, ON, Canada
- fInstitute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- kChild and Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON, Canada
- 1To whom correspondence may be addressed.
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24
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Adult-born dentate granule cells promote hippocampal population sparsity. Nat Neurosci 2022; 25:1481-1491. [PMID: 36216999 PMCID: PMC9630129 DOI: 10.1038/s41593-022-01176-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 09/01/2022] [Indexed: 01/13/2023]
Abstract
The dentate gyrus (DG) gates neocortical information flow to the hippocampus. Intriguingly, the DG also produces adult-born dentate granule cells (abDGCs) throughout the lifespan, but their contribution to downstream firing dynamics remains unclear. Here, we show that abDGCs promote sparser hippocampal population spiking during mnemonic processing of novel stimuli. By combining triple-(DG-CA3-CA1) ensemble recordings and optogenetic interventions in behaving mice, we show that abDGCs constitute a subset of high-firing-rate neurons with enhanced activity responses to novelty and strong modulation by theta oscillations. Selectively activating abDGCs in their 4-7-week post-birth period increases sparsity of hippocampal population patterns, whereas suppressing abDGCs reduces this sparsity, increases principal cell firing rates and impairs novel object recognition with reduced dimensionality of the network firing structure, without affecting single-neuron spatial representations. We propose that adult-born granule cells transiently support sparser hippocampal population activity structure for higher-dimensional responses relevant to effective mnemonic information processing.
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25
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Simonova NA, Volgushev MA, Malyshev AY. Enhanced Non-Associative Long-Term Potentiation in Immature Granule Cells in the Dentate Gyrus of Adult Rats. Front Synaptic Neurosci 2022; 14:889947. [PMID: 35711669 PMCID: PMC9192440 DOI: 10.3389/fnsyn.2022.889947] [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: 03/04/2022] [Accepted: 04/15/2022] [Indexed: 11/20/2022] Open
Abstract
The dentate gyrus is one of the few sites of neurogenesis in the adult brain. Integration of new-generated granule cells into the hippocampal circuitry provides a substrate for structural plasticity, fundamental for normal function of adult hippocampus. However, mechanisms of synaptic plasticity that mediate integration of new-generated granule cells into the existing circuitry remain poorly understood. Especially mechanisms of plasticity at GABA-ergic synapses remain elusive. Here, we show that postsynaptic spiking without presynaptic activation can induce heterosynaptic, non-associative plasticity at GABA-ergic inputs to both immature and mature granule cells. In both immature and mature neurons, plastic changes were bidirectional and individual inputs could express long-term potentiation (LTP) or long-term depression (LTD), or do not change. However, properties of non-associative plasticity dramatically change with maturation of newly generated granule cells: while in immature cells there was a clear predominance of non-associative LTP and net potentiation across the inputs, in mature neurons, potentiation and depression were balanced with no net change on average. We conclude that GABA-ergic inputs to granule cells are plastic, and that the rules for induction of non-associative plasticity change with maturation. We propose that potentiation-biased non-associative plasticity of GABA-ergic transmission might help to counter-balance an increase of excitatory drive that is facilitated by enhanced LTP at glutamatergic synapses in maturating granule cells. Such mechanism might help to build a strong GABA-ergic input to surviving active new cells, necessary for normal function of mature granule cells, which operate under a tight inhibitory control and generate sparse spiking activity.
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Affiliation(s)
- Natalia A. Simonova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russia
| | - Maxim A. Volgushev
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russia
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
- *Correspondence: Maxim A. Volgushev
| | - Alexey Y. Malyshev
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russia
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26
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Shridhar S, Mishra P, Narayanan R. Dominant role of adult neurogenesis-induced structural heterogeneities in driving plasticity heterogeneity in dentate gyrus granule cells. Hippocampus 2022; 32:488-516. [PMID: 35561083 PMCID: PMC9322436 DOI: 10.1002/hipo.23422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 02/02/2023]
Abstract
Neurons and synapses manifest pronounced variability in the amount of plasticity induced by identical activity patterns. The mechanisms underlying such plasticity heterogeneity, which have been implicated in context‐specific resource allocation during encoding, have remained unexplored. Here, we employed a systematic physiologically constrained parametric search to identify the cellular mechanisms behind plasticity heterogeneity in dentate gyrus granule cells. We used heterogeneous model populations to ensure that our conclusions were not biased by parametric choices in a single hand‐tuned model. We found that each of intrinsic, synaptic, and structural heterogeneities independently yielded heterogeneities in synaptic plasticity profiles obtained with two different induction protocols. However, among the disparate forms of neural‐circuit heterogeneities, our analyses demonstrated the dominance of neurogenesis‐induced structural heterogeneities in driving plasticity heterogeneity in granule cells. We found that strong relationships between neuronal intrinsic excitability and plasticity emerged only when adult neurogenesis‐induced heterogeneities in neural structure were accounted for. Importantly, our analyses showed that it was not imperative that the manifestation of neural‐circuit heterogeneities must translate to heterogeneities in plasticity profiles. Specifically, despite the expression of heterogeneities in structural, synaptic, and intrinsic neuronal properties, similar plasticity profiles were attainable across all models through synergistic interactions among these heterogeneities. We assessed the parametric combinations required for the manifestation of such degeneracy in the expression of plasticity profiles. We found that immature cells showed physiological plasticity profiles despite receiving afferent inputs with weak synaptic strengths. Thus, the high intrinsic excitability of immature granule cells was sufficient to counterbalance their low excitatory drive in the expression of plasticity profile degeneracy. Together, our analyses demonstrate that disparate forms of neural‐circuit heterogeneities could mechanistically drive plasticity heterogeneity, but also caution against treating neural‐circuit heterogeneities as proxies for plasticity heterogeneity. Our study emphasizes the need for quantitatively characterizing the relationship between neural‐circuit and plasticity heterogeneities across brain regions.
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Affiliation(s)
- Sameera Shridhar
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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27
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Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy. J Neurosci 2021; 41:9669-9686. [PMID: 34620720 PMCID: PMC8612476 DOI: 10.1523/jneurosci.2439-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/09/2021] [Accepted: 09/21/2021] [Indexed: 11/21/2022] Open
Abstract
In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.SIGNIFICANCE STATEMENT People with temporal lobe epilepsy (TLE) often have learning and memory impairments, sometimes occurring earlier than the first seizure, but those symptoms and their biological underpinnings are poorly understood. We focused on the dentate gyrus, a brain region that is critical to avoid confusion between similar memories and is anatomically disorganized in TLE. We show that both humans and mice with TLE experience confusion between similar situations. This impairment coincides with a failure of the dentate gyrus to disambiguate similar input signals because of pathologic bursting in a subset of neurons. Our work bridges seizure-oriented and memory-oriented views of the dentate gyrus function, suggests a mechanism for cognitive symptoms in TLE, and supports a long-standing hypothesis of episodic memory theories.
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28
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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29
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Martins-Macedo J, Salgado AJ, Gomes ED, Pinto L. Adult brain cytogenesis in the context of mood disorders: From neurogenesis to the emergent role of gliogenesis. Neurosci Biobehav Rev 2021; 131:411-428. [PMID: 34555383 DOI: 10.1016/j.neubiorev.2021.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/06/2021] [Accepted: 09/16/2021] [Indexed: 12/18/2022]
Abstract
Psychiatric disorders severely impact patients' lives. Motivational, cognitive and emotional deficits are the most common symptoms observed in these patients and no effective treatment is still available, either due to the adverse side effects or the low rate of efficacy of currently available drugs. Neurogenesis recovery has been one important focus in the treatment of psychiatric disorders, which undeniably contributes to the therapeutic action of antidepressants. However, glial plasticity is emerging as a new strategy to explore the deficits observed in mood disorders and the efficacy of therapeutic interventions. Thus, it is crucial to understand the mechanisms behind glio- and neurogenesis to better define treatments and preventive therapies, once adult cytogenesis is of pivotal importance to cognitive and emotional components of behavior, both in healthy and pathological contexts, including in psychiatric disorders. Here, we review the concepts and history of neuro- and gliogenesis, providing as well a reflection on the functional importance of cytogenesis in the context of disease.
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Affiliation(s)
- Joana Martins-Macedo
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Eduardo D Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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30
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Zhu Y, Armstrong JN, Contractor A. Kainate receptors regulate the functional properties of young adult-born dentate granule cells. Cell Rep 2021; 36:109751. [PMID: 34551304 PMCID: PMC8525187 DOI: 10.1016/j.celrep.2021.109751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/02/2021] [Accepted: 09/01/2021] [Indexed: 11/06/2022] Open
Abstract
Both inhibitory and excitatory neurotransmitter receptors can influence maturation and survival of adult-born neurons in the dentate gyrus; nevertheless, how these two neurotransmitter systems affect integration of new neurons into the existing circuitry is still not fully characterized. Here, we demonstrate that glutamate receptors of the kainate receptor (KAR) subfamily are expressed in adult-born dentate granule cells (abDGCs) and that, through their interaction with GABAergic signaling mechanisms, they alter the functional properties of adult-born cells during a critical period of their development. Both the intrinsic properties and synaptic connectivity of young abDGCs were affected. Timed KAR loss in a cohort of young adult-born neurons in mice disrupted their performance in a spatial discrimination task but not in a hippocampal-dependent fear conditioning task. Together, these results demonstrate the importance of KARs in the proper functional development of young abDGCs.
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Affiliation(s)
- Yiwen Zhu
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - John N Armstrong
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Anis Contractor
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Department of Neurobiology, Northwestern University, Chicago, IL 60611, USA.
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31
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Moriya F, Shimba K, Kotani K, Jimbo Y. Modulation of dynamics in a pre-existing hippocampal network by neural stem cells on a microelectrode array. J Neural Eng 2021; 18. [PMID: 34380120 DOI: 10.1088/1741-2552/ac1c88] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/11/2021] [Indexed: 11/12/2022]
Abstract
Objective.Neural stem cells (NSCs) are continuously produced throughout life in the hippocampus, which is a vital structure for learning and memory. NSCs in the brain incorporate into the functional hippocampal circuits and contribute to processing information. However, little is known about the mechanisms of NSCs' activity in a pre-existing neuronal network. Here, we investigate the role of NSCs in the neuronal activity of a pre-existing hippocampalin vitronetwork grown on microelectrode arrays.Approach.We assessed the change in internal dynamics of the network by additional NSCs based on spontaneous activity. We also evaluated the networks' ability to discriminate between different input patterns by measuring evoked activity in response to external inputs.Main results.Analysis of spontaneous activity revealed that additional NSCs prolonged network bursts with longer intervals, generated a lower number of initiating patterns, and decreased synchronization among neurons. Moreover, the network with NSCs showed higher synchronicity in close connections among neurons responding to external inputs and a larger difference in spike counts and cross-correlations during evoked response between two different inputs. Taken together, our results suggested that NSCs alter the internal dynamics of the pre-existing hippocampal network and produce more specific responses to external inputs, thus enhancing the ability of the network to differentiate two different inputs.Significance.We demonstrated that NSCs improve the ability to distinguish external inputs by modulating the internal dynamics of a pre-existing network in a hippocampal culture. Our results provide novel insights into the relationship between NSCs and learning and memory.
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Affiliation(s)
- Fumika Moriya
- The Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.,The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Kenta Shimba
- The Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Kiyoshi Kotani
- The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan
| | - Yasuhiko Jimbo
- The Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
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32
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Ogando MB, Pedroncini O, Federman N, Romano SA, Brum LA, Lanuza GM, Refojo D, Marin-Burgin A. Cholinergic modulation of dentate gyrus processing through dynamic reconfiguration of inhibitory circuits. Cell Rep 2021; 36:109572. [PMID: 34433032 DOI: 10.1016/j.celrep.2021.109572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 06/28/2021] [Accepted: 07/30/2021] [Indexed: 10/20/2022] Open
Abstract
The dentate gyrus (DG) of the hippocampus plays a key role in memory formation, and it is known to be modulated by septal projections. By performing electrophysiology and optogenetics, we evaluated the role of cholinergic modulation in the processing of afferent inputs in the DG. We show that mature granule cells (GCs), but not adult-born immature neurons, have increased responses to afferent perforant path stimuli upon cholinergic modulation. This is due to a highly precise reconfiguration of inhibitory circuits, differentially affecting Parvalbumin and Somatostatin interneurons, resulting in a nicotinic-dependent perisomatic disinhibition of GCs. This circuit reorganization provides a mechanism by which mature GCs could escape the strong inhibition they receive, creating a window of opportunity for plasticity. Indeed, coincident activation of perforant path inputs with optogenetic release of acetylcholine produces a long-term potentiated response in GCs, essential for memory formation.
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Affiliation(s)
- Mora B Ogando
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina.
| | - Olivia Pedroncini
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina
| | - Noel Federman
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina
| | - Sebastián A Romano
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina
| | - Luciano A Brum
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - Guillermo M Lanuza
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - Damian Refojo
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina
| | - Antonia Marin-Burgin
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society Godoy Cruz 2390, C1425FQD Buenos Aires, Argentina.
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Giant Y79 retinoblastoma cells contain functionally active T-type calcium channels. Pflugers Arch 2021; 473:1631-1639. [PMID: 34392423 DOI: 10.1007/s00424-021-02612-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/26/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Retinoblastoma is the most common malignant intraocular tumor in children. Y79 human retinoblastoma cells are in vitro models of retinal tumors used for drug screening. Undifferentiated Y79 cells originate from a primitive multi-potential neuroectodermal cell and express neuronal and glial properties. However, the nature of cellular heterogeneity in Y79 cells is unclear because functional methods to characterize neurons or glial cells have not been employed to Y79 cells. Here, we perform patch-clamp recordings to characterize electrophysiological properties in retinoblastoma cells. We identified a population of large-sized Y79 cells (i.e., giant cells, ~ 40-µm diameter), hyperpolarized resting membrane potential (-54 mV), and low input resistance (~ 600 MΩ), indicating electrically mature cells. We also found that giant Y79 cells contain increased density of T-type calcium channels. Finally, we found that T-type calcium channels are active only in giant cells suggesting that cancer treatments aimed to prevent calcium influx in retinoblastomas should be tested in giant cells.
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34
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Vyleta NP, Snyder JS. Prolonged development of long-term potentiation at lateral entorhinal cortex synapses onto adult-born neurons. PLoS One 2021; 16:e0253642. [PMID: 34143843 PMCID: PMC8213073 DOI: 10.1371/journal.pone.0253642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/09/2021] [Indexed: 11/18/2022] Open
Abstract
Critical period plasticity at adult-born neuron synapses is widely believed to contribute to the learning and memory functions of the hippocampus. Experience regulates circuit integration and for a transient interval, until cells are ~6 weeks old, new neurons display enhanced long-term potentiation (LTP) at afferent and efferent synapses. Since neurogenesis declines substantially with age, this raises questions about the extent of lasting plasticity offered by adult-born neurons. Notably, however, the hippocampus receives sensory information from two major cortical pathways. Broadly speaking, the medial entorhinal cortex conveys spatial information to the hippocampus via the medial perforant path (MPP), and the lateral entorhinal cortex, via the lateral perforant path (LPP), codes for the cues and items that make experiences unique. While enhanced critical period plasticity at MPP synapses is relatively well characterized, no studies have examined long-term plasticity at LPP synapses onto adult-born neurons, even though the lateral entorhinal cortex is uniquely vulnerable to aging and Alzheimer's pathology. We therefore investigated LTP at LPP inputs both within (4-6 weeks) and beyond (8+ weeks) the traditional critical period. At immature stages, adult-born neurons did not undergo significant LTP at LPP synapses, and often displayed long-term depression after theta burst stimulation. However, over the course of 3-4 months, adult-born neurons displayed increasingly greater amounts of LTP. Analyses of short-term plasticity point towards a presynaptic mechanism, where transmitter release probability declines as cells mature, providing a greater dynamic range for strengthening synapses. Collectively, our findings identify a novel form of new neuron plasticity that develops over an extended interval, and may therefore be relevant for maintaining cognitive function in aging.
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Affiliation(s)
- Nicholas P. Vyleta
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Jason S. Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- * E-mail:
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35
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Izsak J, Seth H, Theiss S, Hanse E, Illes S. Human Cerebrospinal Fluid Promotes Neuronal Circuit Maturation of Human Induced Pluripotent Stem Cell-Derived 3D Neural Aggregates. Stem Cell Reports 2021; 14:1044-1059. [PMID: 32521247 PMCID: PMC7355159 DOI: 10.1016/j.stemcr.2020.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 05/06/2020] [Accepted: 05/10/2020] [Indexed: 01/09/2023] Open
Abstract
Human induced pluripotent stem cell (hiPSC)-derived in vitro neural and organoid models resemble fetal, rather than adult brain properties, indicating that currently applied cultivation media and supplements are insufficient to achieve neural maturation beyond the fetal stage. In vivo, cerebrospinal fluid molecules are regulating the transition of the immature fetal human brain into a mature adult brain. By culturing hiPSC-3D neural aggregates in human cerebrospinal fluid (hCSF) obtained from healthy adult individuals, we demonstrate that hCSF rapidly triggers neurogenesis, gliogenesis, synapse formation, neurite outgrowth, suppresses proliferation of residing neural stem cells, and results in the formation of synchronously active neuronal circuits in vitro within 3 days. Thus, a physiologically relevant and adult brain-like milieu triggers maturation of hiPSC-3D neural aggregates into highly functional neuronal circuits in vitro. The approach presented here opens a new avenue to identify novel physiological factors for the improvement of hiPSC neural in vitro models. Human CSF triggers rapidly multiple maturation processes in human 3D neural models Human CSF triggers human neurogenesis and suppresses neural stem cell proliferation Human CSF triggers human astrocyte development, neurite growth, and synapse formation Human CSF triggers the maturation of neurons into highly functional neuronal circuits
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Affiliation(s)
- Julia Izsak
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Henrik Seth
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Stephan Theiss
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; Result Medical GmbH, Düsseldorf, Germany
| | - Eric Hanse
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Sebastian Illes
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
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Cuartero MI, García-Culebras A, Torres-López C, Medina V, Fraga E, Vázquez-Reyes S, Jareño-Flores T, García-Segura JM, Lizasoain I, Moro MÁ. Post-stroke Neurogenesis: Friend or Foe? Front Cell Dev Biol 2021; 9:657846. [PMID: 33834025 PMCID: PMC8021779 DOI: 10.3389/fcell.2021.657846] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 02/26/2021] [Indexed: 12/18/2022] Open
Abstract
The substantial clinical burden and disability after stroke injury urges the need to explore therapeutic solutions. Recent compelling evidence supports that neurogenesis persists in the adult mammalian brain and is amenable to regulation in both physiological and pathological situations. Its ability to generate new neurons implies a potential to contribute to recovery after brain injury. However, post-stroke neurogenic response may have different functional consequences. On the one hand, the capacity of newborn neurons to replenish the damaged tissue may be limited. In addition, aberrant forms of neurogenesis have been identified in several insult settings. All these data suggest that adult neurogenesis is at a crossroads between the physiological and the pathological regulation of the neurological function in the injured central nervous system (CNS). Given the complexity of the CNS together with its interaction with the periphery, we ultimately lack in-depth understanding of the key cell types, cell-cell interactions, and molecular pathways involved in the neurogenic response after brain damage and their positive or otherwise deleterious impact. Here we will review the evidence on the stroke-induced neurogenic response and on its potential repercussions on functional outcome. First, we will briefly describe subventricular zone (SVZ) neurogenesis after stroke beside the main evidence supporting its positive role on functional restoration after stroke. Then, we will focus on hippocampal subgranular zone (SGZ) neurogenesis due to the relevance of hippocampus in cognitive functions; we will outline compelling evidence that supports that, after stroke, SGZ neurogenesis may adopt a maladaptive plasticity response further contributing to the development of post-stroke cognitive impairment and dementia. Finally, we will discuss the therapeutic potential of specific steps in the neurogenic cascade that might ameliorate brain malfunctioning and the development of post-stroke cognitive impairment in the chronic phase.
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Affiliation(s)
- María Isabel Cuartero
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Alicia García-Culebras
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Cristina Torres-López
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Violeta Medina
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Enrique Fraga
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Sandra Vázquez-Reyes
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Tania Jareño-Flores
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Juan M. García-Segura
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Ignacio Lizasoain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - María Ángeles Moro
- Neurovascular Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto Universitario de Investigación en Neuroquímica (IUIN), Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
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Jiang N, Cupolillo D, Grosjean N, Muller E, Deforges S, Mulle C, Amédée T. Impaired plasticity of intrinsic excitability in the dentate gyrus alters spike transfer in a mouse model of Alzheimer's disease. Neurobiol Dis 2021; 154:105345. [PMID: 33766653 DOI: 10.1016/j.nbd.2021.105345] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 10/21/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline related to deficits in synaptic transmission and plasticity. We report in APP/PS1 mice, a double transgenic mouse model of AD, that females displayed an early burden of Aβ plaques load in the stratum moleculare of the dentate gyrus (DG) together with prominent neuroinflammatory activation of astrocytes and microglia. Robust deficits in hippocampus-dependent memory tasks were observed in APP/PS1 female mice as early as 3 months of age. We then studied the functional properties of the lateral perforant path (LPP) to DG granule cells. Remarkably DG granule cells displayed higher intrinsic excitability in APP/PS1 female mice. We showed that the long term potentiation of population spike amplitude induced by high frequency stimulation (HFS) at LPP-DG granule cells synapse is impaired in APP/PS1 female mice. HFS induced plasticity of intrinsic excitability in DG granule cells without inducing noticeable modification of synaptic strength. Furthermore, the enhanced intrinsic excitability was potentiated to a greater extent in APP/PS1 as compared to control mice following HFS. Our study shows that changes in the intrinsic excitability of DG granule cells in AD contribute to the dysfunctional transfer of information from the entorhinal cortex to the hippocampus.
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Affiliation(s)
- Nan Jiang
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Dario Cupolillo
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Noelle Grosjean
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Emeline Muller
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Séverine Deforges
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Christophe Mulle
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France
| | - Thierry Amédée
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France.
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38
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Mishra P, Narayanan R. Ion-channel regulation of response decorrelation in a heterogeneous multi-scale model of the dentate gyrus. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100007. [PMID: 33997798 PMCID: PMC7610774 DOI: 10.1016/j.crneur.2021.100007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterogeneities in biological neural circuits manifest in afferent connectivity as well as in local-circuit components such as neuronal excitability, neural structure and local synaptic strengths. The expression of adult neurogenesis in the dentate gyrus (DG) amplifies local-circuit heterogeneities and guides heterogeneities in afferent connectivity. How do neurons and their networks endowed with these distinct forms of heterogeneities respond to perturbations to individual ion channels, which are known to change under several physiological and pathophysiological conditions? We sequentially traversed the ion channels-neurons-network scales and assessed the impact of eliminating individual ion channels on conductance-based neuronal and network models endowed with disparate local-circuit and afferent heterogeneities. We found that many ion channels differentially contributed to specific neuronal or network measurements, and the elimination of any given ion channel altered several functional measurements. We then quantified the impact of ion-channel elimination on response decorrelation, a well-established metric to assess the ability of neurons in a network to convey complementary information, in DG networks endowed with different forms of heterogeneities. Notably, we found that networks constructed with structurally immature neurons exhibited functional robustness, manifesting as minimal changes in response decorrelation in the face of ion-channel elimination. Importantly, the average change in output correlation was dependent on the eliminated ion channel but invariant to input correlation. Our analyses suggest that neurogenesis-driven structural heterogeneities could assist the DG network in providing functional resilience to molecular perturbations. Perturbations at one scale result in a cascading impact on physiology across scales. Heterogeneous multi-scale models used to assess the impact of ion-channel deletion. Mapping of structural components to functional outcomes is many-to-many. Differential & variable impact of ion channel deletion on response decorrelation. Neurogenesis-induced structural heterogeneity confers resilience to perturbations.
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Affiliation(s)
- Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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Lybrand ZR, Goswami S, Zhu J, Jarzabek V, Merlock N, Aktar M, Smith C, Zhang L, Varma P, Cho KO, Ge S, Hsieh J. A critical period of neuronal activity results in aberrant neurogenesis rewiring hippocampal circuitry in a mouse model of epilepsy. Nat Commun 2021; 12:1423. [PMID: 33658509 PMCID: PMC7930276 DOI: 10.1038/s41467-021-21649-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 02/04/2021] [Indexed: 01/31/2023] Open
Abstract
In the mammalian hippocampus, adult-born granule cells (abGCs) contribute to the function of the dentate gyrus (DG). Disruption of the DG circuitry causes spontaneous recurrent seizures (SRS), which can lead to epilepsy. Although abGCs contribute to local inhibitory feedback circuitry, whether they are involved in epileptogenesis remains elusive. Here, we identify a critical window of activity associated with the aberrant maturation of abGCs characterized by abnormal dendrite morphology, ectopic migration, and SRS. Importantly, in a mouse model of temporal lobe epilepsy, silencing aberrant abGCs during this critical period reduces abnormal dendrite morphology, cell migration, and SRS. Using mono-synaptic tracers, we show silencing aberrant abGCs decreases recurrent CA3 back-projections and restores proper cortical connections to the hippocampus. Furthermore, we show that GABA-mediated amplification of intracellular calcium regulates the early critical period of activity. Our results demonstrate that aberrant neurogenesis rewires hippocampal circuitry aggravating epilepsy in mice.
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Affiliation(s)
- Zane R Lybrand
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
- Department of Biology, Texas Woman's University, Denton, TX, USA
| | - Sonal Goswami
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Jingfei Zhu
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Veronica Jarzabek
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Nikolas Merlock
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Mahafuza Aktar
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Courtney Smith
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Ling Zhang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Parul Varma
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Kyung-Ok Cho
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, South Korea
- Department of Biomedicine & Health Sciences, Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Shaoyu Ge
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Jenny Hsieh
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA.
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA.
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40
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Gustus K, Li L, Newville J, Cunningham LA. Functional and Structural Correlates of Impaired Enrichment-Mediated Adult Hippocampal Neurogenesis in a Mouse Model of Prenatal Alcohol Exposure. Brain Plast 2020; 6:67-82. [PMID: 33680847 PMCID: PMC7902980 DOI: 10.3233/bpl-200112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background: Fetal alcohol spectrum disorders (FASDs) are associated with a wide range of cognitive deficiencies. Objective: We previously
found that gestational exposure to moderate levels of alcohol in mice throughout the 1st-2nd human trimester-equivalents
for brain development results in profound impairment of the hippocampal neurogenic response to enriched environment
(EE) in adulthood, without altering baseline neurogenesis rate under standard housing (SH). However, the functional and
structural consequences of impaired EE-mediated neurogenesis in the context of prenatal alcohol exposure (PAE) have
not been determined. Results: Here, we demonstrate that PAE-EE mice display impaired performance on a neurogenesis-dependent
pattern discrimination task, broadened behavioral activation of the dentate gyrus, as assessed by expression of the immediate
early gene, c-Fos, and impaired dendritic branching of adult-generated dentate granule cells (aDGCs). Conclusions: These studies further underscore the impact of moderate gestational alcohol exposure on adult hippocampal plasticity and support adult hippocampal neurogenesis as a potential therapeutic target to remediate certain neurological outcomes in FASD.
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Affiliation(s)
- Kymberly Gustus
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Lu Li
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Jessie Newville
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Lee Anna Cunningham
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
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41
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Sawant-Pokam PA, Vail TJ, Metcalf CS, Maguire JL, McKean TO, McKean NO, Brennan K. Preventing neuronal edema increases network excitability after traumatic brain injury. J Clin Invest 2020; 130:6005-6020. [PMID: 33044227 PMCID: PMC7598047 DOI: 10.1172/jci134793] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 08/06/2020] [Indexed: 12/31/2022] Open
Abstract
Edema is an important target for clinical intervention after traumatic brain injury (TBI). We used in vivo cellular resolution imaging and electrophysiological recording to examine the ionic mechanisms underlying neuronal edema and their effects on neuronal and network excitability after controlled cortical impact (CCI) in mice. Unexpectedly, we found that neuronal edema 48 hours after CCI was associated with reduced cellular and network excitability, concurrent with an increase in the expression ratio of the cation-chloride cotransporters (CCCs) NKCC1 and KCC2. Treatment with the CCC blocker bumetanide prevented neuronal swelling via a reversal in the NKCC1/KCC2 expression ratio, identifying altered chloride flux as the mechanism of neuronal edema. Importantly, bumetanide treatment was associated with increased neuronal and network excitability after injury, including increased susceptibility to spreading depolarizations (SDs) and seizures, known agents of clinical worsening after TBI. Treatment with mannitol, a first-line edema treatment in clinical practice, was also associated with increased susceptibility to SDs and seizures after CCI, showing that neuronal volume reduction, regardless of mechanism, was associated with an excitability increase. Finally, we observed an increase in excitability when neuronal edema normalized by 1 week after CCI. We conclude that neuronal swelling may exert protective effects against damaging excitability in the aftermath of TBI and that treatment of edema has the potential to reverse these effects.
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Affiliation(s)
| | | | - Cameron S. Metcalf
- Anticonvulsant Drug Development Program, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
| | - Jamie L. Maguire
- Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | | | - K.C. Brennan
- Department of Neurology, School of Medicine, and
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Decimo I, Dolci S, Panuccio G, Riva M, Fumagalli G, Bifari F. Meninges: A Widespread Niche of Neural Progenitors for the Brain. Neuroscientist 2020; 27:506-528. [PMID: 32935634 PMCID: PMC8442137 DOI: 10.1177/1073858420954826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Emerging evidence highlights the several roles that meninges play in
relevant brain functions as they are a protective membrane for the
brain, produce and release several trophic factors important for
neural cell migration and survival, control cerebrospinal fluid
dynamics, and embrace numerous immune interactions affecting neural
parenchymal functions. Furthermore, different groups have identified
subsets of neural progenitors residing in the meninges during
development and in the adulthood in different mammalian species,
including humans. Interestingly, these immature neural cells are able
to migrate from the meninges to the neural parenchyma and
differentiate into functional cortical neurons or oligodendrocytes.
Immature neural cells residing in the meninges promptly react to brain
disease. Injury-induced expansion and migration of meningeal neural
progenitors have been observed following experimental demyelination,
traumatic spinal cord and brain injury, amygdala lesion, stroke, and
progressive ataxia. In this review, we summarize data on the function
of meninges as stem cell niche and on the presence of immature neural
cells in the meninges, and discuss their roles in brain health and
disease. Furthermore, we consider the potential exploitation of
meningeal neural progenitors for the regenerative medicine to treat
neurological disorders.
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Affiliation(s)
- Ilaria Decimo
- Laboratory of Pharmacology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Sissi Dolci
- Laboratory of Pharmacology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Gabriella Panuccio
- Enhanced Regenerative Medicine, Istituto Italiano di Tecnologia, Genova, Italy
| | - Marco Riva
- Unit of Neurosurgery, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Guido Fumagalli
- Laboratory of Pharmacology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Francesco Bifari
- Laboratory of Cell Metabolism and Regenerative Medicine, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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43
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Seki T. Understanding the Real State of Human Adult Hippocampal Neurogenesis From Studies of Rodents and Non-human Primates. Front Neurosci 2020; 14:839. [PMID: 32848586 PMCID: PMC7432251 DOI: 10.3389/fnins.2020.00839] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022] Open
Abstract
The concept of adult hippocampal neurogenesis (AHN) has been widely accepted, and a large number of studies have been performed in rodents using modern experimental techniques, which have clarified the nature and developmental processes of adult neural stem/progenitor cells, the functions of AHN, such as memory and learning, and its association with neural diseases. However, a fundamental problem is that it remains unclear as to what extent AHN actually occurs in humans. The answer to this is indispensable when physiological and pathological functions of human AHN are deduced from studies of rodent AHN, but there are controversial data on the extent of human AHN. In this review, studies on AHN performed in rodents and humans will be briefly reviewed, followed by a discussion of the studies in non-human primates. Then, how data of rodent and non-human primate AHN should be applied for understanding human AHN will be discussed.
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Affiliation(s)
- Tatsunori Seki
- Department of Histology and Neuroanatomy, Tokyo Medical University, Tokyo, Japan
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44
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Vaden RJ, Gonzalez JC, Tsai MC, Niver AJ, Fusilier AR, Griffith CM, Kramer RH, Wadiche JI, Overstreet-Wadiche L. Parvalbumin interneurons provide spillover to newborn and mature dentate granule cells. eLife 2020; 9:54125. [PMID: 32602839 PMCID: PMC7326496 DOI: 10.7554/elife.54125] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/19/2020] [Indexed: 01/09/2023] Open
Abstract
Parvalbumin-expressing interneurons (PVs) in the dentate gyrus provide activity-dependent regulation of adult neurogenesis as well as maintain inhibitory control of mature neurons. In mature neurons, PVs evoke GABAA postsynaptic currents (GPSCs) with fast rise and decay phases that allow precise control of spike timing, yet synaptic currents with fast kinetics do not appear in adult-born neurons until several weeks after cell birth. Here we used mouse hippocampal slices to address how PVs signal to newborn neurons prior to the appearance of fast GPSCs. Whereas PV-evoked currents in mature neurons exhibit hallmark fast rise and decay phases, newborn neurons display slow GPSCs with characteristics of spillover signaling. We also unmasked slow spillover currents in mature neurons in the absence of fast GPSCs. Our results suggest that PVs mediate slow spillover signaling in addition to conventional fast synaptic signaling, and that spillover transmission mediates activity-dependent regulation of early events in adult neurogenesis.
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Affiliation(s)
- Ryan J Vaden
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Jose Carlos Gonzalez
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Ming-Chi Tsai
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, United States
| | - Anastasia J Niver
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Allison R Fusilier
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Chelsea M Griffith
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Richard H Kramer
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, United States
| | - Jacques I Wadiche
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
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45
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Adult-Born Hippocampal Neurons Undergo Extended Development and Are Morphologically Distinct from Neonatally-Born Neurons. J Neurosci 2020; 40:5740-5756. [PMID: 32571837 DOI: 10.1523/jneurosci.1665-19.2020] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 02/28/2020] [Accepted: 05/04/2020] [Indexed: 11/21/2022] Open
Abstract
During immature stages, adult-born neurons pass through critical periods for survival and plasticity. It is generally assumed that by 2 months of age adult-born neurons are mature and equivalent to the broader neuronal population, raising questions of how they might contribute to hippocampal function in old age when neurogenesis has declined. However, few have examined adult-born neurons beyond the critical period or directly compared them to neurons born in infancy. Here, we used a retrovirus to visualize functionally relevant morphological features of 2- to 24-week-old adult-born neurons in male rats. From 2 to 7 weeks, neurons grew and attained a relatively mature phenotype. However, several features of 7-week-old neurons suggested a later wave of growth: these neurons had larger nuclei, thicker dendrites, and more dendritic filopodia than all other groups. Indeed, between 7 and 24 weeks, adult-born neurons gained additional dendritic branches, formed a second primary dendrite, acquired more mushroom spines, and had enlarged mossy fiber presynaptic terminals. Compared with neonatal-born neurons, old adult-born neurons had greater spine density, larger presynaptic terminals, and more putative efferent filopodial contacts onto inhibitory neurons. By integrating rates of cell birth and growth across the life span, we estimate that adult neurogenesis ultimately produces half of the cells and the majority of spines in the dentate gyrus. Critically, protracted development contributes to the plasticity of the hippocampus through to the end of life, even after cell production declines. Persistent differences from neonatal-born neurons may additionally endow adult-born neurons with unique functions even after they have matured.SIGNIFICANCE STATEMENT Neurogenesis occurs in the hippocampus throughout adult life and contributes to memory and emotion. It is generally assumed that new neurons have the greatest impact on behavior when they are immature and plastic. However, since neurogenesis declines dramatically with age, it is unclear how they might contribute to behavior later in life when cell proliferation has slowed. Here we find that newborn neurons mature over many months in rats and may end up with distinct morphological features compared with neurons born in infancy. Using a mathematical model, we estimate that a large fraction of neurons is added in adulthood. Moreover, their extended growth produces a reserve of plasticity that persists even after neurogenesis has declined to low rates.
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46
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Do antidepressants promote neurogenesis in adult hippocampus? A systematic review and meta-analysis on naive rodents. Pharmacol Ther 2020; 210:107515. [DOI: 10.1016/j.pharmthera.2020.107515] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/13/2020] [Indexed: 02/07/2023]
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47
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Sun X, Bernstein MJ, Meng M, Rao S, Sørensen AT, Yao L, Zhang X, Anikeeva PO, Lin Y. Functionally Distinct Neuronal Ensembles within the Memory Engram. Cell 2020; 181:410-423.e17. [PMID: 32187527 PMCID: PMC7166195 DOI: 10.1016/j.cell.2020.02.055] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 10/31/2019] [Accepted: 02/26/2020] [Indexed: 10/24/2022]
Abstract
Memories are believed to be encoded by sparse ensembles of neurons in the brain. However, it remains unclear whether there is functional heterogeneity within individual memory engrams, i.e., if separate neuronal subpopulations encode distinct aspects of the memory and drive memory expression differently. Here, we show that contextual fear memory engrams in the mouse dentate gyrus contain functionally distinct neuronal ensembles, genetically defined by the Fos- or Npas4-dependent transcriptional pathways. The Fos-dependent ensemble promotes memory generalization and receives enhanced excitatory synaptic inputs from the medial entorhinal cortex, which we find itself also mediates generalization. The Npas4-dependent ensemble promotes memory discrimination and receives enhanced inhibitory drive from local cholecystokinin-expressing interneurons, the activity of which is required for discrimination. Our study provides causal evidence for functional heterogeneity within the memory engram and reveals synaptic and circuit mechanisms used by each ensemble to regulate the memory discrimination-generalization balance.
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Affiliation(s)
- Xiaochen Sun
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Molecular and Cellular Neuroscience Graduate Program, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Max J Bernstein
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Meizhen Meng
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Siyuan Rao
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andreas T Sørensen
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Li Yao
- State Key Laboratory of Cognitive Neuroscience & Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Xiaohui Zhang
- State Key Laboratory of Cognitive Neuroscience & Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Polina O Anikeeva
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yingxi Lin
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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48
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Kv4.1, a Key Ion Channel For Low Frequency Firing of Dentate Granule Cells, Is Crucial for Pattern Separation. J Neurosci 2020; 40:2200-2214. [PMID: 32047055 DOI: 10.1523/jneurosci.1541-19.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 12/30/2019] [Accepted: 01/23/2020] [Indexed: 11/21/2022] Open
Abstract
The dentate gyrus (DG) in the hippocampus may play key roles in remembering distinct episodes through pattern separation, which may be subserved by the sparse firing properties of granule cells (GCs) in the DG. Low intrinsic excitability is characteristic of mature GCs, but ion channel mechanisms are not fully understood. Here, we investigated ionic channel mechanisms for firing frequency regulation in hippocampal GCs using male and female mice, and identified Kv4.1 as a key player. Immunofluorescence analysis showed that Kv4.1 was preferentially expressed in the DG, and its expression level determined by Western blot analysis was higher at 8-week than 3-week-old mice, suggesting a developmental regulation of Kv4.1 expression. With respect to firing frequency, GCs are categorized into two distinctive groups: low-frequency (LF) and high-frequency (HF) firing GCs. Input resistance (R in) of most LF-GCs is lower than 200 MΩ, suggesting that LF-GCs are fully mature GCs. Kv4.1 channel inhibition by intracellular perfusion of Kv4.1 antibody increased firing rates and gain of the input-output relationship selectively in LF-GCs with no significant effect on resting membrane potential and R in, but had no effect in HF-GCs. Importantly, mature GCs from mice depleted of Kv4.1 transcripts in the DG showed increased firing frequency, and these mice showed an impairment in contextual discrimination task. Our findings suggest that Kv4.1 expression occurring at late stage of GC maturation is essential for low excitability of DG networks and thereby contributes to pattern separation.SIGNIFICANCE STATEMENT The sparse activity of dentate granule cells (GCs), which is essential for pattern separation, is supported by high inhibitory inputs and low intrinsic excitability of GCs. Low excitability of GCs is thought to be attributable to a high K+ conductance at resting membrane potentials, but this study identifies Kv4.1, a depolarization-activated K+ channel, as a key ion channel that regulates firing of GCs without affecting resting membrane potentials. Kv4.1 expression is developmentally regulated and Kv4.1 currents are detected only in mature GCs that show low-frequency firing, but not in less mature high-frequency firing GCs. Furthermore, mice depleted of Kv4.1 transcripts in the dentate gyrus show impaired pattern separation, suggesting that Kv4.1 is crucial for sparse coding and pattern separation.
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49
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Abstract
The dentate gyrus continually produces new neurons throughout life. Behavioral studies in rodents and network models show that new neurons contribute to normal dentate functions, but there are many unanswered questions about how the relatively small population of new neurons alters network activity. Here we discuss experimental evidence that supports multiple cellular mechanisms by which adult-born neurons contribute to circuit function. Whereas past work focused on the unique intrinsic properties of young neurons, more recent studies also suggest that adult-born neurons alter the excitability of the mature neuronal population via unexpected circuit interactions.
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Affiliation(s)
- Cristina V Dieni
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jose Carlos Gonzalez
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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50
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Dumenieu M, Senkov O, Mironov A, Bourinet E, Kreutz MR, Dityatev A, Heine M, Bikbaev A, Lopez-Rojas J. The Low-Threshold Calcium Channel Cav3.2 Mediates Burst Firing of Mature Dentate Granule Cells. Cereb Cortex 2019; 28:2594-2609. [PMID: 29790938 PMCID: PMC5998957 DOI: 10.1093/cercor/bhy084] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Indexed: 12/11/2022] Open
Abstract
Mature granule cells are poorly excitable neurons that were recently shown to fire action potentials, preferentially in bursts. It is believed that the particularly pronounced short-term facilitation of mossy fiber synapses makes granule cell bursting a very effective means of properly transferring information to CA3. However, the mechanism underlying the unique bursting behavior of mature granule cells is currently unknown. Here, we show that Cav3.2 T-type channels at the axon initial segment are responsible for burst firing of mature granule cells in rats and mice. Accordingly, Cav3.2 knockout mice fire tonic spikes and exhibit impaired bursting, synaptic plasticity and dentate-to-CA3 communication. The data show that Cav3.2 channels are strong modulators of bursting and can be considered a critical molecular switch that enables effective information transfer from mature granule cells to the CA3 pyramids.
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Affiliation(s)
- Mael Dumenieu
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestr. 6, Magdeburg, Germany
| | - Oleg Senkov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Andrey Mironov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.,Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Emmanuel Bourinet
- Calcium Channel Dynamics & Nociception Group, Institute of Functional Genomics, Montpellier, France
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestr. 6, Magdeburg, Germany.,Leibniz Group "Dendritic Organelles and Synaptic Function," University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), Hamburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.,Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | - Martin Heine
- Research Group Molecular Physiology, Leibniz Institute for Neurobiology, Brenneckestr. 6, Magdeburg, Germany
| | - Arthur Bikbaev
- Research Group Molecular Physiology, Leibniz Institute for Neurobiology, Brenneckestr. 6, Magdeburg, Germany
| | - Jeffrey Lopez-Rojas
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestr. 6, Magdeburg, Germany
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