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Ferraguti F, Fredes F, Hou WH, Somogyi P, Thompson S. Marco Capogna, a pioneering neuroscientist and true European. Eur J Neurosci 2023; 57:1629-1638. [PMID: 37070614 DOI: 10.1111/ejn.15950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/23/2023] [Accepted: 02/25/2023] [Indexed: 04/19/2023]
Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Felipe Fredes
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Wen-Hsien Hou
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Scott Thompson
- Department of Psychiatry, University of Colorado School of Medicine, Aurora, Colorado, USA
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2
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Lukacs IP, Francavilla R, Field M, Hunter E, Howarth M, Horie S, Plaha P, Stacey R, Livermore L, Ansorge O, Tamas G, Somogyi P. Differential effects of group III metabotropic glutamate receptors on spontaneous inhibitory synaptic currents in spine-innervating double bouquet and parvalbumin-expressing dendrite-targeting GABAergic interneurons in human neocortex. Cereb Cortex 2023; 33:2101-2142. [PMID: 35667019 PMCID: PMC9977385 DOI: 10.1093/cercor/bhac195] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/12/2022] Open
Abstract
Diverse neocortical GABAergic neurons specialize in synaptic targeting and their effects are modulated by presynaptic metabotropic glutamate receptors (mGluRs) suppressing neurotransmitter release in rodents, but their effects in human neocortex are unknown. We tested whether activation of group III mGluRs by L-AP4 changes GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) in 2 distinct dendritic spine-innervating GABAergic interneurons recorded in vitro in human neocortex. Calbindin-positive double bouquet cells (DBCs) had columnar "horsetail" axons descending through layers II-V innervating dendritic spines (48%) and shafts, but not somata of pyramidal and nonpyramidal neurons. Parvalbumin-expressing dendrite-targeting cell (PV-DTC) axons extended in all directions innervating dendritic spines (22%), shafts (65%), and somata (13%). As measured, 20% of GABAergic neuropil synapses innervate spines, hence DBCs, but not PV-DTCs, preferentially select spine targets. Group III mGluR activation paradoxically increased the frequency of sIPSCs in DBCs (to median 137% of baseline) but suppressed it in PV-DTCs (median 92%), leaving the amplitude unchanged. The facilitation of sIPSCs in DBCs may result from their unique GABAergic input being disinhibited via network effect. We conclude that dendritic spines receive specialized, diverse GABAergic inputs, and group III mGluRs differentially regulate GABAergic synaptic transmission to distinct GABAergic cell types in human cortex.
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Affiliation(s)
- Istvan P Lukacs
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | | | - Martin Field
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Emily Hunter
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Michael Howarth
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Sawa Horie
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Puneet Plaha
- Department of Neurosurgery, John Radcliffe Hospital, OUH NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Richard Stacey
- Department of Neurosurgery, John Radcliffe Hospital, OUH NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Laurent Livermore
- Department of Neurosurgery, John Radcliffe Hospital, OUH NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Olaf Ansorge
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Gabor Tamas
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, 6726 Szeged, Hungary
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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3
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Viney TJ, Sarkany B, Ozdemir AT, Hartwich K, Schweimer J, Bannerman D, Somogyi P. Spread of pathological human Tau from neurons to oligodendrocytes and loss of high-firing pyramidal neurons in aging mice. Cell Rep 2022; 41:111646. [PMID: 36384116 PMCID: PMC9681663 DOI: 10.1016/j.celrep.2022.111646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 08/23/2022] [Accepted: 10/20/2022] [Indexed: 11/18/2022] Open
Abstract
Intracellular aggregation of hyperphosphorylated Tau (pTau) in the brain is associated with cognitive and motor impairments, and ultimately neurodegeneration. We investigate how human pTau affects cells and network activity in the hippocampal formation of the THY-Tau22 tauopathy model mice in vivo. We find that pTau preferentially accumulates in deep-layer pyramidal neurons, leading to neurodegeneration, and we establish that pTau spreads to oligodendrocytes. During goal-directed virtual navigation in aged transgenic mice, we detect fewer high-firing prosubicular pyramidal cells, but the firing population retains its coupling to theta oscillations. Analysis of network oscillations and firing patterns of pyramidal and GABAergic neurons recorded in head-fixed and freely moving mice suggests preserved neuronal coordination. In spatial memory tests, transgenic mice have reduced short-term familiarity, but spatial working and reference memory are surprisingly normal. We hypothesize that unimpaired subcortical network mechanisms maintain cortical neuronal coordination, counteracting the widespread pTau aggregation, loss of high-firing cells, and neurodegeneration.
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Affiliation(s)
- Tim J Viney
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.
| | - Barbara Sarkany
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - A Tugrul Ozdemir
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Katja Hartwich
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Judith Schweimer
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - David Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, UK
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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4
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Yuste R, Hawrylycz M, Aalling N, Aguilar-Valles A, Arendt D, Armañanzas R, Ascoli GA, Bielza C, Bokharaie V, Bergmann TB, Bystron I, Capogna M, Chang Y, Clemens A, de Kock CPJ, DeFelipe J, Dos Santos SE, Dunville K, Feldmeyer D, Fiáth R, Fishell GJ, Foggetti A, Gao X, Ghaderi P, Goriounova NA, Güntürkün O, Hagihara K, Hall VJ, Helmstaedter M, Herculano-Houzel S, Hilscher MM, Hirase H, Hjerling-Leffler J, Hodge R, Huang J, Huda R, Khodosevich K, Kiehn O, Koch H, Kuebler ES, Kühnemund M, Larrañaga P, Lelieveldt B, Louth EL, Lui JH, Mansvelder HD, Marin O, Martinez-Trujillo J, Chameh HM, Mohapatra AN, Munguba H, Nedergaard M, Němec P, Ofer N, Pfisterer UG, Pontes S, Redmond W, Rossier J, Sanes JR, Scheuermann RH, Serrano-Saiz E, Staiger JF, Somogyi P, Tamás G, Tolias AS, Tosches MA, García MT, Wozny C, Wuttke TV, Liu Y, Yuan J, Zeng H, Lein E. A community-based transcriptomics classification and nomenclature of neocortical cell types. Nat Neurosci 2021; 23:1456-1468. [PMID: 32839617 PMCID: PMC7683348 DOI: 10.1038/s41593-020-0685-8] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To understand the function of cortical circuits, it is necessary to catalog their cellular diversity. Past attempts to do so using anatomical, physiological or molecular features of cortical cells have not resulted in a unified taxonomy of neuronal or glial cell types, partly due to limited data. Single-cell transcriptomics is enabling, for the first time, systematic high-throughput measurements of cortical cells and generation of datasets that hold the promise of being complete, accurate and permanent. Statistical analyses of these data reveal clusters that often correspond to cell types previously defined by morphological or physiological criteria and that appear conserved across cortical areas and species. To capitalize on these new methods, we propose the adoption of a transcriptome-based taxonomy of cell types for mammalian neocortex. This classification should be hierarchical and use a standardized nomenclature. It should be based on a probabilistic definition of a cell type and incorporate data from different approaches, developmental stages and species. A community-based classification and data aggregation model, such as a knowledge graph, could provide a common foundation for the study of cortical circuits. This community-based classification, nomenclature and data aggregation could serve as an example for cell type atlases in other parts of the body.
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Affiliation(s)
| | | | | | | | - Detlev Arendt
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ruben Armañanzas
- George Mason University, Fairfax, VA, USA.,BrainScope Company Inc., Bethesda, MD, USA
| | | | | | - Vahid Bokharaie
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | | | | | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - YoonJeung Chang
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | | | | | - Richárd Fiáth
- Research Centre for Natural Sciences, Budapest, Hungary
| | | | | | - Xuefan Gao
- European Molecular Biology Laboratory, Hamburg, Germany
| | - Parviz Ghaderi
- École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | | | - Kenta Hagihara
- Friedrich Miescher Institute for Biological Research, Basel, Switzerland
| | | | | | | | - Markus M Hilscher
- Karolinska Institutet, Stockholm, Sweden.,Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | | | | | | | - Josh Huang
- Cold Spring Harbor Laboratory, Laurel Hollow, NY, USA
| | - Rafiq Huda
- WM Keck Center for Collaborative Neuroscience, Department of Cell Biology and Neuroscience, Rutgers University - New Brunswick, Piscataway, NJ, USA
| | | | - Ole Kiehn
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Eric S Kuebler
- Robarts Research Institute, Western University, London, Ontario, Canada
| | | | | | | | | | - Jan H Lui
- Stanford University, Stanford, CA, USA
| | | | | | - Julio Martinez-Trujillo
- Schulich School of Medicine and Dentistry, Departments of Physiology, Pharmacology and Psychiatry, University of Western Ontario, London, Ontario, Canada
| | | | | | | | | | | | | | | | | | | | | | | | - Richard H Scheuermann
- J. Craig Venter Institute, La Jolla, CA, USA.,Department of Pathology, University of California, San Diego, CA, USA
| | | | - Jochen F Staiger
- Institute for Neuroanatomy, University of Göttingen, Göttingen, Germany
| | | | | | | | | | | | - Christian Wozny
- University of Strathclyde, Glasgow, UK.,MSH Medical School, Hamburg, Germany
| | - Thomas V Wuttke
- Departments of Neurosurgery and of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yong Liu
- University of Copenhagen, Copenhagen, Denmark
| | - Juan Yuan
- Karolinska Institutet, Stockholm, Sweden
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA.
| | - Ed Lein
- Allen Institute for Brain Science, Seattle, WA, USA.
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5
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Joshi A, Somogyi P. Changing phase relationship of the stepping rhythm to neuronal oscillatory theta activity in the septo-hippocampal network of mice. Brain Struct Funct 2020; 225:871-879. [PMID: 32060639 PMCID: PMC7046600 DOI: 10.1007/s00429-020-02031-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 01/22/2020] [Indexed: 12/24/2022]
Abstract
Movement-related sensory and motor activity in the brain contributes to cognitive processes. We have observed that the frequency of stepping rhythm in head-fixed mice running on a jetball overlaps with the range of frequencies that characterize hippocampal rhythmic slow activity, including theta (~ 3 to 10 Hz). On average, step-cycle troughs (i.e. when the paw touches the ground) were weakly coupled to hippocampal theta oscillations. This weak coupling was sustained during a range of running speeds. In short temporal windows, step-cycle troughs were synchronous with hippocampal theta oscillatory cycle troughs, while during other periods they led or lagged behind theta cycles. Furthermore, simultaneously recorded theta rhythmic medial septal neurons in the basal forebrain were phase-coupled to both step-cycles and theta-cycles. We propose that the weak overall phase relationship of step-cycles with theta-cycles signifies a distinct mode of information processing. Transient synchronization of the step-cycle with theta may indicate the engagement of septo-hippocampal-entorhinal network with the current heading of the animal.
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Affiliation(s)
- Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
- Department of Physiology, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, USA.
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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6
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Katona L, Hartwich K, Tomioka R, Somogyi J, Roberts JDB, Wagner K, Joshi A, Klausberger T, Rockland KS, Somogyi P. Synaptic organisation and behaviour-dependent activity of mGluR8a-innervated GABAergic trilaminar cells projecting from the hippocampus to the subiculum. Brain Struct Funct 2020; 225:705-734. [PMID: 32016558 PMCID: PMC7046583 DOI: 10.1007/s00429-020-02029-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023]
Abstract
In the hippocampal CA1 area, the GABAergic trilaminar cells have their axon distributed locally in three layers and also innervate the subiculum. Trilaminar cells have a high level of somato-dendritic muscarinic M2 acetylcholine receptor, lack somatostatin expression and their presynaptic inputs are enriched in mGluR8a. But the origin of their inputs and their behaviour-dependent activity remain to be characterised. Here we demonstrate that (1) GABAergic neurons with the molecular features of trilaminar cells are present in CA1 and CA3 in both rats and mice. (2) Trilaminar cells receive mGluR8a-enriched GABAergic inputs, e.g. from the medial septum, which are probably susceptible to hetero-synaptic modulation of neurotransmitter release by group III mGluRs. (3) An electron microscopic analysis identifies trilaminar cell output synapses with specialised postsynaptic densities and a strong bias towards interneurons as targets, including parvalbumin-expressing cells in the CA1 area. (4) Recordings in freely moving rats revealed the network state-dependent segregation of trilaminar cell activity, with reduced firing during movement, but substantial increase in activity with prolonged burst firing (> 200 Hz) during slow wave sleep. We predict that the behaviour-dependent temporal dynamics of trilaminar cell firing are regulated by their specialised inhibitory inputs. Trilaminar cells might support glutamatergic principal cells by disinhibition and mediate the binding of neuronal assemblies between the hippocampus and the subiculum via the transient inhibition of local interneurons.
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Affiliation(s)
- Linda Katona
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Katja Hartwich
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ryohei Tomioka
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Morphological Neural Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jozsef Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - J David B Roberts
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Kristina Wagner
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Department of Physiology, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA
| | - Thomas Klausberger
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, 1090, Vienna, Austria
| | - Kathleen S Rockland
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Anatomy and Neurobiology, Boston University School of Medicine, 72 East Concord St., Boston, MA, 02118, USA
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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Bocchio M, Lukacs IP, Stacey R, Plaha P, Apostolopoulos V, Livermore L, Sen A, Ansorge O, Gillies MJ, Somogyi P, Capogna M. Group II Metabotropic Glutamate Receptors Mediate Presynaptic Inhibition of Excitatory Transmission in Pyramidal Neurons of the Human Cerebral Cortex. Front Cell Neurosci 2019; 12:508. [PMID: 30670948 PMCID: PMC6333023 DOI: 10.3389/fncel.2018.00508] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 12/07/2018] [Indexed: 01/09/2023] Open
Abstract
Group II metabotropic glutamate receptor (mGluR) ligands are potential novel drugs for neurological and psychiatric disorders, but little is known about the effects of these compounds at synapses of the human cerebral cortex. Investigating the effects of neuropsychiatric drugs in human brain tissue with preserved synaptic circuits might accelerate the development of more potent and selective pharmacological treatments. We have studied the effects of group II mGluR activation on excitatory synaptic transmission recorded from pyramidal neurons of cortical layers 2-3 in acute slices derived from surgically removed cortical tissue of people with epilepsy or tumors. The application of a selective group II mGluR agonist, LY354740 (0.1-1 μM) inhibited the amplitude and frequency of action potential-dependent spontaneous excitatory postsynaptic currents (sEPSCs). This effect was prevented by the application of a group II/III mGluR antagonist, CPPG (0.1 mM). Furthermore, LY354740 inhibited the frequency, but not the amplitude, of action potential-independent miniature EPSCs (mEPSCs) recorded in pyramidal neurons. Finally, LY354740 did slightly reduce cells' input resistance without altering the holding current of the neurons recorded in voltage clamp at -90 mV. Our results suggest that group II mGluRs are mainly auto-receptors that inhibit the release of glutamate onto pyramidal neurons in layers 2-3 in the human cerebral cortex, thereby regulating network excitability. We have demonstrated the effect of a group II mGluR ligand at human cortical synapses, revealing mechanisms by which these drugs could exert pro-cognitive effects and treat human neuropsychiatric disorders.
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Affiliation(s)
- Marco Bocchio
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Istvan P. Lukacs
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Richard Stacey
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Puneet Plaha
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Vasileios Apostolopoulos
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Laurent Livermore
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Arjune Sen
- Oxford Epilepsy Research Group, NIHR Biomedical Research Centre, Oxford, United Kingdom
- Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Olaf Ansorge
- Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Martin J. Gillies
- Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- The Danish Research Institute of Translational Neuroscience, Nordic EMBL Partnership for Molecular Medicine – Department of Biomedicine, Aarhus University, Aarhus, Denmark
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8
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Francavilla R, Villette V, Luo X, Chamberland S, Muñoz-Pino E, Camiré O, Wagner K, Kis V, Somogyi P, Topolnik L. Connectivity and network state-dependent recruitment of long-range VIP-GABAergic neurons in the mouse hippocampus. Nat Commun 2018; 9:5043. [PMID: 30487571 PMCID: PMC6261953 DOI: 10.1038/s41467-018-07162-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 10/18/2018] [Indexed: 11/21/2022] Open
Abstract
GABAergic interneurons in the hippocampus provide for local and long-distance coordination of neurons in functionally connected areas. Vasoactive intestinal peptide-expressing (VIP+) interneurons occupy a distinct niche in circuitry as many of them specialize in innervating GABAergic cells, thus providing network disinhibition. In the CA1 hippocampus, VIP+ interneuron-selective cells target local interneurons. Here, we discover a type of VIP+ neuron whose axon innervates CA1 and also projects to the subiculum (VIP-LRPs). VIP-LRPs show specific molecular properties and target interneurons within the CA1 area but both interneurons and pyramidal cells within subiculum. They are interconnected through gap junctions but demonstrate sparse spike coupling in vitro. In awake mice, VIP-LRPs decrease their activity during theta-run epochs and are more active during quiet wakefulness but not coupled to sharp-wave ripples. Together, the data provide evidence for VIP interneuron molecular diversity and functional specialization in controlling cell ensembles along the hippocampo-subicular axis.
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Affiliation(s)
- Ruggiero Francavilla
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Vincent Villette
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Xiao Luo
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Simon Chamberland
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Einer Muñoz-Pino
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Olivier Camiré
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Kristina Wagner
- Department of Pharmacology, Oxford University, Oxford, OX1 3QT, UK
| | - Viktor Kis
- Department of Pharmacology, Oxford University, Oxford, OX1 3QT, UK
| | - Peter Somogyi
- Department of Pharmacology, Oxford University, Oxford, OX1 3QT, UK
| | - Lisa Topolnik
- Neuroscience Axis, CHU de Québec Research Center, Université Laval, Quebec, QC, G1V 4G2, Canada.
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval, Quebec, QC, G1V 0A6, Canada.
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9
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Harris KD, Hochgerner H, Skene NG, Magno L, Katona L, Bengtsson Gonzales C, Somogyi P, Kessaris N, Linnarsson S, Hjerling-Leffler J. Classes and continua of hippocampal CA1 inhibitory neurons revealed by single-cell transcriptomics. PLoS Biol 2018; 16:e2006387. [PMID: 29912866 PMCID: PMC6029811 DOI: 10.1371/journal.pbio.2006387] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/03/2018] [Accepted: 05/22/2018] [Indexed: 01/19/2023] Open
Abstract
Understanding any brain circuit will require a categorization of its constituent neurons. In hippocampal area CA1, at least 23 classes of GABAergic neuron have been proposed to date. However, this list may be incomplete; additionally, it is unclear whether discrete classes are sufficient to describe the diversity of cortical inhibitory neurons or whether continuous modes of variability are also required. We studied the transcriptomes of 3,663 CA1 inhibitory cells, revealing 10 major GABAergic groups that divided into 49 fine-scale clusters. All previously described and several novel cell classes were identified, with three previously described classes unexpectedly found to be identical. A division into discrete classes, however, was not sufficient to describe the diversity of these cells, as continuous variation also occurred between and within classes. Latent factor analysis revealed that a single continuous variable could predict the expression levels of several genes, which correlated similarly with it across multiple cell types. Analysis of the genes correlating with this variable suggested it reflects a range from metabolically highly active faster-spiking cells that proximally target pyramidal cells to slower-spiking cells targeting distal dendrites or interneurons. These results elucidate the complexity of inhibitory neurons in one of the simplest cortical structures and show that characterizing these cells requires continuous modes of variation as well as discrete cell classes.
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Affiliation(s)
- Kenneth D. Harris
- University College London Institute of Neurology, London, United Kingdom
- University College London Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Hannah Hochgerner
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nathan G. Skene
- University College London Institute of Neurology, London, United Kingdom
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Lorenza Magno
- University College London Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Linda Katona
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Carolina Bengtsson Gonzales
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Nicoletta Kessaris
- University College London Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Sten Linnarsson
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jens Hjerling-Leffler
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Viney TJ, Salib M, Joshi A, Unal G, Berry N, Somogyi P. Shared rhythmic subcortical GABAergic input to the entorhinal cortex and presubiculum. eLife 2018; 7:e34395. [PMID: 29620525 PMCID: PMC5908441 DOI: 10.7554/elife.34395] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/04/2018] [Indexed: 01/06/2023] Open
Abstract
Rhythmic theta frequency (~5-12 Hz) oscillations coordinate neuronal synchrony and higher frequency oscillations across the cortex. Spatial navigation and context-dependent episodic memories are represented in several interconnected regions including the hippocampal and entorhinal cortices, but the cellular mechanisms for their dynamic coupling remain to be defined. Using monosynaptically-restricted retrograde viral tracing in mice, we identified a subcortical GABAergic input from the medial septum that terminated in the entorhinal cortex, with collaterals innervating the dorsal presubiculum. Extracellularly recording and labeling GABAergic entorhinal-projecting neurons in awake behaving mice show that these subcortical neurons, named orchid cells, fire in long rhythmic bursts during immobility and locomotion. Orchid cells discharge near the peak of hippocampal and entorhinal theta oscillations, couple to entorhinal gamma oscillations, and target subpopulations of extra-hippocampal GABAergic interneurons. Thus, orchid cells are a specialized source of rhythmic subcortical GABAergic modulation of 'upstream' and 'downstream' cortico-cortical circuits involved in mnemonic functions.
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Affiliation(s)
- Tim James Viney
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Minas Salib
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Abhilasha Joshi
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Gunes Unal
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Naomi Berry
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Peter Somogyi
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
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11
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Unal G, Crump MG, Viney TJ, Éltes T, Katona L, Klausberger T, Somogyi P. Spatio-temporal specialization of GABAergic septo-hippocampal neurons for rhythmic network activity. Brain Struct Funct 2018; 223:2409-2432. [PMID: 29500537 PMCID: PMC5968071 DOI: 10.1007/s00429-018-1626-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/10/2018] [Indexed: 01/06/2023]
Abstract
Medial septal GABAergic neurons of the basal forebrain innervate the hippocampus and related cortical areas, contributing to the coordination of network activity, such as theta oscillations and sharp wave-ripple events, via a preferential innervation of GABAergic interneurons. Individual medial septal neurons display diverse activity patterns, which may be related to their termination in different cortical areas and/or to the different types of innervated interneurons. To test these hypotheses, we extracellularly recorded and juxtacellularly labeled single medial septal neurons in anesthetized rats in vivo during hippocampal theta and ripple oscillations, traced their axons to distant cortical target areas, and analyzed their postsynaptic interneurons. Medial septal GABAergic neurons exhibiting different hippocampal theta phase preferences and/or sharp wave-ripple related activity terminated in restricted hippocampal regions, and selectively targeted a limited number of interneuron types, as established on the basis of molecular markers. We demonstrate the preferential innervation of bistratified cells in CA1 and of basket cells in CA3 by individual axons. One group of septal neurons was suppressed during sharp wave-ripples, maintained their firing rate across theta and non-theta network states and mainly fired along the descending phase of CA1 theta oscillations. In contrast, neurons that were active during sharp wave-ripples increased their firing significantly during "theta" compared to "non-theta" states, with most firing during the ascending phase of theta oscillations. These results demonstrate that specialized septal GABAergic neurons contribute to the coordination of network activity through parallel, target area- and cell type-selective projections to the hippocampus.
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Affiliation(s)
- Gunes Unal
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Department of Psychology, Bogazici University, 34342, Istanbul, Turkey.
| | - Michael G Crump
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tim J Viney
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tímea Éltes
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary
| | - Linda Katona
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Thomas Klausberger
- Center for Brain Research, Medical University of Vienna, 1090, Vienna, Austria
| | - Peter Somogyi
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary.
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Joshi A, Salib M, Viney TJ, Dupret D, Somogyi P. Behavior-Dependent Activity and Synaptic Organization of Septo-hippocampal GABAergic Neurons Selectively Targeting the Hippocampal CA3 Area. Neuron 2017; 96:1342-1357.e5. [PMID: 29198757 PMCID: PMC5746169 DOI: 10.1016/j.neuron.2017.10.033] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/23/2017] [Accepted: 10/25/2017] [Indexed: 12/12/2022]
Abstract
Rhythmic medial septal (MS) GABAergic input coordinates cortical theta oscillations. However, the rules of innervation of cortical cells and regions by diverse septal neurons are unknown. We report a specialized population of septal GABAergic neurons, the Teevra cells, selectively innervating the hippocampal CA3 area bypassing CA1, CA2, and the dentate gyrus. Parvalbumin-immunopositive Teevra cells show the highest rhythmicity among MS neurons and fire with short burst duration (median, 38 ms) preferentially at the trough of both CA1 theta and slow irregular oscillations, coincident with highest hippocampal excitability. Teevra cells synaptically target GABAergic axo-axonic and some CCK interneurons in restricted septo-temporal CA3 segments. The rhythmicity of their firing decreases from septal to temporal termination of individual axons. We hypothesize that Teevra neurons coordinate oscillatory activity across the septo-temporal axis, phasing the firing of specific CA3 interneurons, thereby contributing to the selection of pyramidal cell assemblies at the theta trough via disinhibition. VIDEO ABSTRACT.
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Affiliation(s)
- Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK.
| | - Minas Salib
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Tim James Viney
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - David Dupret
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; Center for Brain Research, Medical University of Vienna, Vienna 1090, Austria.
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13
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Katona L, Micklem B, Borhegyi Z, Swiejkowski DA, Valenti O, Viney TJ, Kotzadimitriou D, Klausberger T, Somogyi P. Behavior-dependent activity patterns of GABAergic long-range projecting neurons in the rat hippocampus. Hippocampus 2017; 27:359-377. [PMID: 27997999 PMCID: PMC5363363 DOI: 10.1002/hipo.22696] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2016] [Indexed: 11/10/2022]
Abstract
Long-range glutamatergic and GABAergic projections participate in temporal coordination of neuronal activity in distributed cortical areas. In the hippocampus, GABAergic neurons project to the medial septum and retrohippocampal areas. Many GABAergic projection cells express somatostatin (SOM+) and, together with locally terminating SOM+ bistratified and O-LM cells, contribute to dendritic inhibition of pyramidal cells. We tested the hypothesis that diversity in SOM+ cells reflects temporal specialization during behavior using extracellular single cell recording and juxtacellular neurobiotin-labeling in freely moving rats. We have demonstrated that rare GABAergic projection neurons discharge rhythmically and are remarkably diverse. During sharp wave-ripples, most projection cells, including a novel SOM+ GABAergic back-projecting cell, increased their activity similar to bistratified cells, but unlike O-LM cells. During movement, most projection cells discharged along the descending slope of theta cycles, but some fired at the trough jointly with bistratified and O-LM cells. The specialization of hippocampal SOM+ projection neurons complements the action of local interneurons in differentially phasing inputs from the CA3 area to CA1 pyramidal cell dendrites during sleep and wakefulness. Our observations suggest that GABAergic projection cells mediate the behavior- and network state-dependent binding of neuronal assemblies amongst functionally-related brain regions by transmitting local rhythmic entrainment of neurons in CA1 to neuronal populations in other areas. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Linda Katona
- Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3QTUK
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- MRC Brain Network Dynamics Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
| | - Ben Micklem
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- MRC Brain Network Dynamics Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
| | - Zsolt Borhegyi
- Center for Brain Research, Medical University of ViennaViennaA‐1090Austria
- Department of BiochemistryEötvös Loránd UniversityBudapest1117Hungary
| | - Daniel A. Swiejkowski
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
| | - Ornella Valenti
- Center for Brain Research, Medical University of ViennaViennaA‐1090Austria
- Department of Neurophysiology and NeuropharmacologyCenter for Physiology and Pharmacology, Medical University of ViennaVienna1090Austria
| | - Tim J. Viney
- Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3QTUK
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- MRC Brain Network Dynamics Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
| | - Dimitrios Kotzadimitriou
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
| | - Thomas Klausberger
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- Center for Brain Research, Medical University of ViennaViennaA‐1090Austria
| | - Peter Somogyi
- Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3QTUK
- MRC Anatomical Neuropharmacology Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- MRC Brain Network Dynamics Unit, Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3THUK
- Center for Brain Research, Medical University of ViennaViennaA‐1090Austria
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14
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Lakatos T, Major B, Somogyi P, Vacz G, Simon M, Hornyak I, Lacza Z. Platelet-Rich Plasma Enhanced Bone Autograft in Femoral Head Necrosis-A Case Series Report on a Six-Year Follow-Up Period. ACTA ACUST UNITED AC 2017. [DOI: 10.4172/2329-9509.1000205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Lau PYP, Katona L, Saghy P, Newton K, Somogyi P, Lamsa KP. Long-term plasticity in identified hippocampal GABAergic interneurons in the CA1 area in vivo. Brain Struct Funct 2016; 222:1809-1827. [PMID: 27783219 PMCID: PMC5406446 DOI: 10.1007/s00429-016-1309-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 09/11/2016] [Indexed: 12/24/2022]
Abstract
Long-term plasticity is well documented in synapses between glutamatergic principal cells in the cortex both in vitro and in vivo. Long-term potentiation (LTP) and -depression (LTD) have also been reported in glutamatergic connections to hippocampal GABAergic interneurons expressing parvalbumin (PV+) or nitric oxide synthase (NOS+) in brain slices, but plasticity in these cells has not been tested in vivo. We investigated synaptically-evoked suprathreshold excitation of identified hippocampal neurons in the CA1 area of urethane-anaesthetized rats. Neurons were recorded extracellularly with glass microelectrodes, and labelled with neurobiotin for anatomical analyses. Single-shock electrical stimulation of afferents from the contralateral CA1 elicited postsynaptic action potentials with monosynaptic features showing short delay (9.95 ± 0.41 ms) and small jitter in 13 neurons through the commissural pathway. Theta-burst stimulation (TBS) generated LTP of the synaptically-evoked spike probability in pyramidal cells, and in a bistratified cell and two unidentified fast-spiking interneurons. On the contrary, PV+ basket cells and NOS+ ivy cells exhibited either LTD or LTP. An identified axo-axonic cell failed to show long-term change in its response to stimulation. Discharge of the cells did not explain whether LTP or LTD was generated. For the fast-spiking interneurons, as a group, no correlation was found between plasticity and local field potential oscillations (1-3 or 3-6 Hz components) recorded immediately prior to TBS. The results demonstrate activity-induced long-term plasticity in synaptic excitation of hippocampal PV+ and NOS+ interneurons in vivo. Physiological and pathological activity patterns in vivo may generate similar plasticity in these interneurons.
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Affiliation(s)
| | - Linda Katona
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, OX1 3TH, UK
| | - Peter Saghy
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, OX1 3TH, UK
| | - Kathryn Newton
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK.,MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, OX1 3TH, UK
| | - Peter Somogyi
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, OX1 3TH, UK.
| | - Karri P Lamsa
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK. .,Department of Anatomy, Physiology and Neuroscience, University of Szeged, Közép fasor, Szeged, 6720, Hungary.
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16
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Barth A, Burkhalter A, Callaway EM, Connors BW, Cauli B, DeFelipe J, Feldmeyer D, Freund T, Kawaguchi Y, Kisvarday Z, Kubota Y, McBain C, Oberlaender M, Rossier J, Rudy B, Staiger JF, Somogyi P, Tamas G, Yuste R. Comment on "Principles of connectivity among morphologically defined cell types in adult neocortex". Science 2016; 353:1108. [PMID: 27609882 DOI: 10.1126/science.aaf5663] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/03/2016] [Indexed: 01/15/2023]
Abstract
Jiang et al (Research Article, 27 November 2015, aac9462) describe detailed experiments that substantially add to the knowledge of cortical microcircuitry and are unique in the number of connections reported and the quality of interneuron reconstruction. The work appeals to experts and laypersons because of the notion that it unveils new principles and provides a complete description of cortical circuits. We provide a counterbalance to the authors' claims to give those less familiar with the minutiae of cortical circuits a better sense of the contributions and the limitations of this study.
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Affiliation(s)
- Alison Barth
- 159C Mellon Institute, Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Andreas Burkhalter
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Edward M Callaway
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Barry W Connors
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA
| | - Bruno Cauli
- Neuroscience Paris Seine (NPS), Cortical Network and Neurovascular Coupling (CNNC), CNRS UMR 8246, Inserm U 1130, UPMC UM 119, Université Pierre et Marie Curie, 9 Quai Saint Bernard, 75005 Paris, France
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnologia Biomedica, Universidad Politecnica de Madrid, Campus Montegancedo S/N, Pozuelo de Alarcon, 28223 Madrid, Spain. Instituto Cajal (CSIC), Avenida Doctor Arce 37, 28002 Madrid, Spain
| | - Dirk Feldmeyer
- Institut für Neurowissenschaften und Medizin (INM-2), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Tamas Freund
- Department of Cellular and Network Neurobiology, Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450 Budapest, POB 67, Hungary
| | - Yasuo Kawaguchi
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, 5-1 Myodaiji-Higashiyama, Okazaki, Aichi 444-8787, Japan
| | - Zoltan Kisvarday
- University of Debrecen, Department of Anatomy, Histology, Embryology, Laboratory for Cortical Systems Neuroscience, Nagyerdei krt. 98, 4012 Debrecen, Hungary
| | - Yoshiyuki Kubota
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, 5-1 Myodaiji-Higashiyama, Okazaki, Aichi 444-8787, Japan
| | - Chris McBain
- Laboratory of Cellular and Synaptic Neurophysiology, National Institute of Child Health and Human Development, 35 Convent Drive MSC3715, Bethesda, MD 20892, USA
| | - Marcel Oberlaender
- Max Planck Institute for Biological Cybernetics, Computational Neuroanatomy Group, D-72076 Tubingen, Germany
| | - Jean Rossier
- Neuroscience Paris Seine, Univerisité Pierre et Marie Curie (UPMC) Paris VI, 7-9 Quai Saint Bernard, 75005 Paris, France
| | - Bernardo Rudy
- Neuroscience Institute, Department of Anesthesiology, Perioperative Care, and Pain Medicine, New York University School of Medicine, Smilow Research Center, 522 First Avenue, New York, NY 10016, USA.
| | - Jochen F Staiger
- University Medicine Goettingen, Center for Anatomy, Institute for Neuroanatomy, Kreuzbergring 36, D-37075 Goettingen, Germany.
| | - Peter Somogyi
- Medical Research Council Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK
| | - Gabor Tamas
- Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép Fasor 52, Szeged, H-6726 Hungary
| | - Rafael Yuste
- Kavli institute of Brain Science, Columbia University, Department of Biological Sciences, West 120 Street, New York, NY 10027, USA
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Varga C, Tamas G, Barzo P, Olah S, Somogyi P. Molecular and Electrophysiological Characterization of GABAergic Interneurons Expressing the Transcription Factor COUP-TFII in the Adult Human Temporal Cortex. Cereb Cortex 2015; 25:4430-49. [PMID: 25787832 PMCID: PMC4768361 DOI: 10.1093/cercor/bhv045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcription factors contribute to the differentiation of cortical neurons, orchestrate specific interneuronal circuits, and define synaptic relationships. We have investigated neurons expressing chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), which plays a role in the migration of GABAergic neurons. Whole-cell, patch-clamp recording in vitro combined with colocalization of molecular cell markers in the adult cortex differentiates distinct interneurons. The majority of strongly COUP-TFII-expressing neurons were in layers I–III. Most calretinin (CR) and/or cholecystokinin- (CCK) and/or reelin-positive interneurons were also COUP-TFII-positive. CR-, CCK-, or reelin-positive neurons formed 80%, 20%, or 17% of COUP-TFII-positive interneurons, respectively. About half of COUP-TFII-/CCK-positive interneurons were CR-positive, a quarter of them reelin-positive, but none expressed both. Interneurons positive for COUP-TFII fired irregular, accommodating and adapting trains of action potentials (APs) and innervated mostly small dendritic shafts and rarely spines or somata. Paired recording showed that a calretinin-/COUP-TFII-positive interneuron elicited inhibitory postsynaptic potentials (IPSPs) in a reciprocally connected pyramidal cell. Calbindin, somatostatin, or parvalbumin-immunoreactive interneurons and most pyramidal cells express no immunohistochemically detectable COUP-TFII. In layers V and VI, some pyramidal cells expressed a low level of COUP-TFII in the nucleus. In conclusion, COUP-TFII is expressed in a diverse subset of GABAergic interneurons predominantly innervating small dendritic shafts originating from both interneurons and pyramidal cells.
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Affiliation(s)
- Csaba Varga
- Research Group for Cortical Microcircuits of the Hungarian Academy of Science, Department of Physiology, Anatomy and Neuroscience MRC, Brain Networks Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK Current address: Szentágothai Research Centre, Department of Physiology, University of Pécs, Pécs, Hungary
| | - Gabor Tamas
- Research Group for Cortical Microcircuits of the Hungarian Academy of Science, Department of Physiology, Anatomy and Neuroscience
| | - Pal Barzo
- Department of Neurosurgery, University of Szeged, Szeged, Hungary
| | - Szabolcs Olah
- Research Group for Cortical Microcircuits of the Hungarian Academy of Science, Department of Physiology, Anatomy and Neuroscience
| | - Peter Somogyi
- MRC, Brain Networks Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Katona L, Lapray D, Viney TJ, Oulhaj A, Borhegyi Z, Micklem BR, Klausberger T, Somogyi P. Sleep and movement differentiates actions of two types of somatostatin-expressing GABAergic interneuron in rat hippocampus. Neuron 2014; 82:872-86. [PMID: 24794095 PMCID: PMC4041064 DOI: 10.1016/j.neuron.2014.04.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2014] [Indexed: 01/26/2023]
Abstract
Neuropeptides acting on pre- and postsynaptic receptors are coreleased with GABA by interneurons including bistratified and O-LM cells, both expressing somatostatin but innervating segregated dendritic domains of pyramidal cells. Neuropeptide release requires high-frequency action potentials, but the firing patterns of most peptide/GABA-releasing interneurons during behavior are unknown. We show that behavioral and network states differentiate the activities of bistratified and O-LM cells in freely moving rats. Bistratified cells fire at higher rates during sleep than O-LM cells and, unlike O-LM cells, strongly increase spiking during sharp wave-associated ripples (SWRs). In contrast, O-LM interneurons decrease firing during sleep relative to awake states and are mostly inhibited during SWRs. During movement, both cell types fire cooperatively at the troughs of theta oscillations but with different frequencies. Somatostatin and GABA are differentially released to distinct dendritic zones of CA1 pyramidal cells during sleep and wakefulness to coordinate segregated glutamatergic inputs from entorhinal cortex and CA3. Bistratified and O-LM cells release GABA and somatostatin to distinct dendrites During movement the two cells cooperate temporally but fire at different frequencies During sleep bistratified cells are strongly active, O-LM cells decrease firing Behavior differentiates GABA and somatostatin release to distinct dendritic zones
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Affiliation(s)
- Linda Katona
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK.
| | - Damien Lapray
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK
| | - Tim J Viney
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK
| | - Abderrahim Oulhaj
- Institute of Public Health, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, P.O. Box 17666, United Arab Emirates
| | - Zsolt Borhegyi
- Center for Brain Research, Medical University of Vienna, Spitalgasse 4, Vienna, A-1090, Austria
| | - Benjamin R Micklem
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK
| | - Thomas Klausberger
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK; Center for Brain Research, Medical University of Vienna, Spitalgasse 4, Vienna, A-1090, Austria.
| | - Peter Somogyi
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3TH, UK; Center for Brain Research, Medical University of Vienna, Spitalgasse 4, Vienna, A-1090, Austria.
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19
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Somogyi P, Katona L, Klausberger T, Lasztóczi B, Viney TJ. Temporal redistribution of inhibition over neuronal subcellular domains underlies state-dependent rhythmic change of excitability in the hippocampus. Philos Trans R Soc Lond B Biol Sci 2013; 369:20120518. [PMID: 24366131 PMCID: PMC3866441 DOI: 10.1098/rstb.2012.0518] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The behaviour-contingent rhythmic synchronization of neuronal activity is reported by local field potential oscillations in the theta, gamma and sharp wave-related ripple (SWR) frequency ranges. In the hippocampus, pyramidal cell assemblies representing temporal sequences are coordinated by GABAergic interneurons selectively innervating specific postsynaptic domains, and discharging phase locked to network oscillations. We compare the cellular network dynamics in the CA1 and CA3 areas recorded with or without anaesthesia. All parts of pyramidal cells, except the axon initial segment, receive GABA from multiple interneuron types, each with distinct firing dynamics. The axon initial segment is exclusively innervated by axo-axonic cells, preferentially firing after the peak of the pyramidal layer theta cycle, when pyramidal cells are least active. Axo-axonic cells are inhibited during SWRs, when many pyramidal cells fire synchronously. This dual inverse correlation demonstrates the key inhibitory role of axo-axonic cells. Parvalbumin-expressing basket cells fire phase locked to field gamma activity in both CA1 and CA3, and also strongly increase firing during SWRs, together with dendrite-innervating bistratified cells, phasing pyramidal cell discharge. Subcellular domain-specific GABAergic innervation probably developed for the coordination of multiple glutamatergic inputs on different parts of pyramidal cells through the temporally distinct activity of GABAergic interneurons, which differentially change their firing during different network states.
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Affiliation(s)
- Peter Somogyi
- Medical Research Council, Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, , Mansfield Road, Oxford OX1 3TH, UK
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Gulyás B, Somogyi P. JÁNOS SZENTÁGOTHAI. 31 October 1912 - 8 September 1994: Elected ForMemRs 20 April 1978. Biogr Mem Fellows R Soc 2013; 59:383-406. [PMID: 26113752 PMCID: PMC4477047 DOI: 10.1098/rsbm.2012.0038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
János Szentágothai was an eminent, creative and renowned neuroscientist, who made pioneering and seminal discoveries contributing to our current understanding of brain functions. His vision of the brain as a network of specific populations of nerve cells, each engaging in selective operations and self-organizing into modules, has provided the framework and stimulus for generations of neuroscientists. His irrepressible curiosity and enthusiasm for the beauty in the organization of the brain never faded. He had a towering intellect and was a great humanist. Szentágothai was born in Budapest, Hungary, in 1912 and died in his native city in 1994. He was educated and worked in Hungary. During the six decades of his scientific activity, he made remarkably original and lasting contributions to the neurosciences, including the exploration of basic architectural features of many brain areas, the functional-anatomical bases of elementary brain operations such as reflex arcs, the vestibulo-ocular system, the brain control of hormonal regulation, general organizational principles of the neuraxis, the organization of the cerebellum and the modular organization of the neocortex. He left for posterity not only his discoveries, which have stood the test of time, but also a vigorous school of pupils as well as a large number of friends and admirers. Thanks to him neuroscience is one of the strongest scientific fields in Hungary today.
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Affiliation(s)
- Balázs Gulyás
- Department of Clinical Neuroscience, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Peter Somogyi
- MRC Anatomical Neuropharmacology Unit, University of Oxford, Oxford OX1 3TH, UK
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Viney TJ, Lasztoczi B, Katona L, Crump MG, Tukker JJ, Klausberger T, Somogyi P. Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo. Nat Neurosci 2013; 16:1802-1811. [PMID: 24141313 DOI: 10.1038/nn.3550] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 09/18/2013] [Indexed: 11/09/2022]
Abstract
Hippocampal sharp waves are population discharges initiated by an unknown mechanism in pyramidal cell networks of CA3. Axo-axonic cells (AACs) regulate action potential generation through GABAergic synapses on the axon initial segment. We found that CA3 AACs in anesthetized rats and AACs in freely moving rats stopped firing during sharp waves, when pyramidal cells fire most. AACs fired strongly and rhythmically around the peak of theta oscillations, when pyramidal cells fire at low probability. Distinguishing AACs from other parvalbumin-expressing interneurons by their lack of detectable SATB1 transcription factor immunoreactivity, we discovered a somatic GABAergic input originating from the medial septum that preferentially targets AACs. We recorded septo-hippocampal GABAergic cells that were activated during hippocampal sharp waves and projected to CA3. We hypothesize that inhibition of AACs, and the resulting subcellular redistribution of inhibition from the axon initial segment to other pyramidal cell domains, is a necessary condition for the emergence of sharp waves promoting memory consolidation.
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Affiliation(s)
- Tim J Viney
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Balint Lasztoczi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Linda Katona
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Michael G Crump
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - John J Tukker
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Peter Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
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Lapray D, Lasztoczi B, Lagler M, Viney TJ, Katona L, Valenti O, Hartwich K, Borhegyi Z, Somogyi P, Klausberger T. Behavior-dependent specialization of identified hippocampal interneurons. Nat Neurosci 2012; 15:1265-71. [PMID: 22864613 DOI: 10.1038/nn.3176] [Citation(s) in RCA: 192] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 06/28/2012] [Indexed: 11/09/2022]
Abstract
A large variety of GABAergic interneurons control information processing in the hippocampal circuits governing the formation of neuronal representations. Whether distinct hippocampal interneuron types contribute differentially to information processing during behavior is not known. We employed a new technique for recording and labeling interneurons and pyramidal cells in drug-free, freely moving rats. Recorded parvalbumin-expressing basket interneurons innervated somata and proximal pyramidal cell dendrites, whereas nitric oxide synthase- and neuropeptide Y-expressing ivy cells provided synaptic and extrasynaptic dendritic modulation. Basket and ivy cells showed distinct spike-timing dynamics, firing at different rates and times during theta and ripple oscillations. Basket, but not ivy, cells changed their firing rates during movement, sleep and quiet wakefulness, suggesting that basket cells coordinate cell assemblies in a behavioral state-contingent manner, whereas persistently firing ivy cells might control network excitability and homeostasis. Different interneuron types provide GABA to specific subcellular domains at defined times and rates, thereby differentially controlling network activity during behavior.
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Affiliation(s)
- Damien Lapray
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.
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Takács VT, Klausberger T, Somogyi P, Freund TF, Gulyás AI. Extrinsic and local glutamatergic inputs of the rat hippocampal CA1 area differentially innervate pyramidal cells and interneurons. Hippocampus 2012; 22:1379-91. [PMID: 21956752 PMCID: PMC4473063 DOI: 10.1002/hipo.20974] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 07/21/2011] [Indexed: 11/08/2022]
Abstract
The two main glutamatergic pathways to the CA1 area, the Schaffer collateral/commissural input and the entorhinal fibers, as well as the local axons of CA1 pyramidal cells innervate both pyramidal cells and interneurons. To determine whether these inputs differ in their weights of activating GABAergic circuits, we have studied the relative proportion of pyramidal cells and interneurons among their postsynaptic targets in serial electron microscopic sections. Local axons of CA1 pyramidal cells, intracellularly labeled in vitro or in vivo, innervated a relatively high proportion of interneuronal postsynaptic targets (65.9 and 53.8%, in vitro and in vivo, respectively) in stratum (str.) oriens and alveus. In contrast, axons of in vitro labeled CA3 pyramidal cells in str. oriens and str. radiatum of the CA1 area made synaptic junctions predominantly with pyramidal cell spines (92.9%). The postsynaptic targets of anterogradely labeled medial entorhinal cortical boutons in CA1 str. lacunosum-moleculare were primarily pyramidal neuron dendritic spines and shafts (90.8%). The alvear group of the entorhinal afferents, traversing str. oriens, str. pyramidale, and str. radiatum showed a higher preference for innervating GABAergic cells (21.3%), particularly in str. oriens/alveus. These data demonstrate that different glutamatergic pathways innervate CA1 GABAergic cells to different extents. The results suggest that the numerically smaller CA1 local axonal inputs together with the alvear part of the entorhinal input preferentially act on GABAergic interneurons in contrast to the CA3, or the entorhinal input in str. lacunosum-moleculare. The results highlight differences in the postsynaptic target selection of the feed-forward versus recurrent glutamatergic inputs to the CA1 and CA3 areas.
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Affiliation(s)
- Virág T Takács
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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Somogyi J, Szabo A, Somogyi P, Lamsa K. Molecular analysis of ivy cells of the hippocampal CA1 stratum radiatum using spectral identification of immunofluorophores. Front Neural Circuits 2012; 6:35. [PMID: 22666191 PMCID: PMC3364487 DOI: 10.3389/fncir.2012.00035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 05/18/2012] [Indexed: 11/13/2022] Open
Abstract
Neuronal nitric oxide synthase-expressing (nNOS+) GABAergic interneurons are common in hippocampal stratum (str.) radiatum. However, these cells are less well characterized than nNOS+ ivy cells in str. pyramidale or neurogliaform cells (NGC) in str. lacunosum-moleculare. Here we have studied the laminar distribution of the axons and dendrites, and the immunoreactivity of these neurons recorded in rat hippocampal slices. We have used spectral analysis of antibody- or streptavidin-conjugated fluorophores to improve recognition of genuine signals in reactions for molecules such as nNOS and neuropeptide-Y (NPY). We found that most nNOS+ cells with soma in the CA1 area str. radiatum exhibit characteristic properties of ivy cells, and were positive for NPY and negative for reelin. However, laminar distributions of their neurites differ from original characterization of ivy cells with the soma in or close to str. pyramidale. Both their dendrites and axon are mainly in str. radiatum and to a lesser extent in str. oriens, and in addition often extend to str. lacunosum-moleculare. We conclude that ivy cells in str. radiatum may predominantly be feedforward inhibitory interneurons in the CA1 area, and their axonal output delivering GABA, NPY, and NO can influence both the entorhinal cortex innervated and the CA3 innervated zones pre- and post-synaptically. Spectral analysis of fluorophores provides an objective algorithm to analyze signals in immunoreactions for neurochemical markers.
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Affiliation(s)
- Jozsef Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University Oxford, UK
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Kasugai Y, Swinny JD, Roberts JDB, Dalezios Y, Fukazawa Y, Sieghart W, Shigemoto R, Somogyi P. Quantitative localisation of synaptic and extrasynaptic GABAA receptor subunits on hippocampal pyramidal cells by freeze-fracture replica immunolabelling. Eur J Neurosci 2010; 32:1868-88. [PMID: 21073549 PMCID: PMC4487817 DOI: 10.1111/j.1460-9568.2010.07473.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hippocampal CA1 pyramidal cells, which receive γ-aminobutyric acid (GABA)ergic input from at least 18 types of presynaptic neuron, express 14 subunits of the pentameric GABA(A) receptor. The relative contribution of any subunit to synaptic and extrasynaptic receptors influences the dynamics of GABA and drug actions. Synaptic receptors mediate phasic GABA-evoked conductance and extrasynaptic receptors contribute to a tonic conductance. We used freeze-fracture replica-immunogold labelling, a sensitive quantitative immunocytochemical method, to detect synaptic and extrasynaptic pools of the alpha1, alpha2 and beta3 subunits. Antibodies to the cytoplasmic loop of the subunits showed immunogold particles concentrated on distinct clusters of intramembrane particles (IMPs) on the cytoplasmic face of the plasma membrane on the somata, dendrites and axon initial segments, with an abrupt decrease in labelling at the edge of the IMP cluster. Neuroligin-2, a GABAergic synapse-specific adhesion molecule, co-labels all beta3 subunit-rich IMP clusters, therefore we considered them synapses. Double-labelling for two subunits showed that virtually all somatic synapses contain the alpha1, alpha2 and beta3 subunits. The extrasynaptic plasma membrane of the somata, dendrites and dendritic spines showed low-density immunolabelling. Synaptic labelling densities on somata for the alpha1, alpha2 and beta3 subunits were 78-132, 94 and 79 times higher than on the extrasynaptic membranes, respectively. As GABAergic synapses occupy 0.72% of the soma surface, the fraction of synaptic labelling was 33-48 (alpha1), 40 (alpha2) and 36 (beta3)% of the total somatic surface immunolabelling. Assuming similar antibody access to all receptors, about 60% of these subunits are in extrasynaptic receptors.
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Affiliation(s)
- Yu Kasugai
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan.
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Dren CN, Nemeth I, Sari I, Ratz F, Glavits R, Somogyi P. Isolation of a reticuloendotheliosis-like virus from naturally occurring lymphoreticular tumours of domestic goose. Avian Pathol 2008; 17:259-77. [PMID: 18766685 DOI: 10.1080/03079458808436446] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Naturally occurring lymphoreticular tumours were found in an adult goose flock. Diffuse and/or nodular lymphoma-like tumours occurred in the spleen, liver, pancreas, intestines and rarely in other internal organs. Osteopetrosis-like lesions and signs of other diseases such as amidostomosis, enteritis, arthritis and air sacculitis were also observed. The tumourous lesions consisted of proliferations of undifferentiated lymphoblasts and slightly differentiated plasmablasts of the bursal system of lymphocytes. Tumour cell proliferation was usually associated with parenchymal atrophy and occasionally with amyloid depositions along the walls of capillaries of the spleen and the liver. In tissue cultures, chloroform sensitive, typical C-type virus particles of about 100 nm were isolated. The isolate incorporated 3H-uridine, banded at about 1.19 to 1.20 g/cm(3) in sucrose gradient ultracentrifugation and was shown to be antigenically related to the reticuloendotheliosis group of avian retroviruses. In transmission experiments with chickens and geese, one of the four tested reticuloendotheliosis virus-positive cellular field materials caused a highly lethal neoplastic disease similar in cytology to that seen in the natural disease outbreak within four weeks after infection. The other three cellular field materials and the tissue-culture-propagated virus isolates induced either a runting disease syndrome or a similar chronic neoplasia to that found in the naturally diseased geese during an experimental period of 30 weeks. Reticuloendotheliosis virus was reisolated from the experimentally inoculated birds, and antibodies to the T strain of reticuloendotheliosis virus were also demonstrated in sera of surviving chickens. Neither Marek's disease virus nor avian leukosis-sarcoma viruses could be demonstrated in tissue cultures or in chickens of transmission experiments. The reported transmissible lymphoreticular tumours of domestic goose seem to be associated with infection of a new isolate of the reticuloendotheliosis group of viruses designated as Reticuloendotheliosis Virus Hungary-2 (REV-H-2).
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Affiliation(s)
- C N Dren
- Hungarian Academy of Sciences, Veterinary Medical Research Institute, Budapest, Hungary
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Abstract
In the cerebral cortex, diverse types of neurons form intricate circuits and cooperate in time for the processing and storage of information. Recent advances reveal a spatiotemporal division of labor in cortical circuits, as exemplified in the CA1 hippocampal area. In particular, distinct GABAergic (gamma-aminobutyric acid-releasing) cell types subdivide the surface of pyramidal cells and act in discrete time windows, either on the same or on different subcellular compartments. They also interact with glutamatergic pyramidal cell inputs in a domain-specific manner and support synaptic temporal dynamics, network oscillations, selection of cell assemblies, and the implementation of brain states. The spatiotemporal specializations in cortical circuits reveal that cellular diversity and temporal dynamics coemerged during evolution, providing a basis for cognitive behavior.
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Affiliation(s)
- Thomas Klausberger
- MRC Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, UK.
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Fuentealba P, Begum R, Capogna M, Jinno S, Márton LF, Csicsvari J, Thomson A, Somogyi P, Klausberger T. Ivy cells: a population of nitric-oxide-producing, slow-spiking GABAergic neurons and their involvement in hippocampal network activity. Neuron 2008; 57:917-29. [PMID: 18367092 DOI: 10.1016/j.neuron.2008.01.034] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2007] [Revised: 12/08/2007] [Accepted: 01/24/2008] [Indexed: 10/22/2022]
Abstract
In the cerebral cortex, GABAergic interneurons are often regarded as fast-spiking cells. We have identified a type of slow-spiking interneuron that offers distinct contributions to network activity. "Ivy" cells, named after their dense and fine axons innervating mostly basal and oblique pyramidal cell dendrites, are more numerous than the parvalbumin-expressing basket, bistratified, or axo-axonic cells. Ivy cells express nitric oxide synthase, neuropeptide Y, and high levels of GABA(A) receptor alpha1 subunit; they discharge at a low frequency with wide spikes in vivo, yet are distinctively phase-locked to behaviorally relevant network rhythms including theta, gamma, and ripple oscillations. Paired recordings in vitro showed that Ivy cells receive depressing EPSPs from pyramidal cells, which in turn receive slowly rising and decaying inhibitory input from Ivy cells. In contrast to fast-spiking interneurons operating with millisecond precision, the highly abundant Ivy cells express presynaptically acting neuromodulators and regulate the excitability of pyramidal cell dendrites through slowly rising and decaying GABAergic inputs.
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Affiliation(s)
- Pablo Fuentealba
- MRC Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, UK
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Jinno S, Klausberger T, Marton LF, Dalezios Y, Roberts JDB, Fuentealba P, Bushong EA, Henze D, Buzsáki G, Somogyi P. Neuronal diversity in GABAergic long-range projections from the hippocampus. J Neurosci 2007; 27:8790-804. [PMID: 17699661 PMCID: PMC2270609 DOI: 10.1523/jneurosci.1847-07.2007] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The formation and recall of sensory, motor, and cognitive representations require coordinated fast communication among multiple cortical areas. Interareal projections are mainly mediated by glutamatergic pyramidal cell projections; only few long-range GABAergic connections have been reported. Using in vivo recording and labeling of single cells and retrograde axonal tracing, we demonstrate novel long-range GABAergic projection neurons in the rat hippocampus: (1) somatostatin- and predominantly mGluR1alpha-positive neurons in stratum oriens project to the subiculum, other cortical areas, and the medial septum; (2) neurons in stratum oriens, including somatostatin-negative ones; and (3) trilaminar cells project to the subiculum and/or other cortical areas but not the septum. These three populations strongly increase their firing during sharp wave-associated ripple oscillations, communicating this network state to the septotemporal system. Finally, a large population of somatostatin-negative GABAergic cells in stratum radiatum project to the molecular layers of the subiculum, presubiculum, retrosplenial cortex, and indusium griseum and fire rhythmically at high rates during theta oscillations but do not increase their firing during ripples. The GABAergic projection axons have a larger diameter and thicker myelin sheet than those of CA1 pyramidal cells. Therefore, rhythmic IPSCs are likely to precede the arrival of excitation in cortical areas (e.g., subiculum) that receive both glutamatergic and GABAergic projections from the CA1 area. Other areas, including the retrosplenial cortex, receive only rhythmic GABAergic CA1 input. We conclude that direct GABAergic projections from the hippocampus to other cortical areas and the septum contribute to coordinating oscillatory timing across structures.
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Affiliation(s)
- Shozo Jinno
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
| | - Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
- Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Laszlo F. Marton
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
- Neural Systems Research Group, Faculty of Engineering, Sapientia-Hungarian University of Transylvania, RO-540485 Targu Mures, Romania
| | - Yannis Dalezios
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
- Faculty of Medicine, University of Crete, 71003 Heraklion, Greece
- Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, GR-711 10 Heraklion, Greece, and
| | - J. David B. Roberts
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
| | - Pablo Fuentealba
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
| | - Eric A. Bushong
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
| | - Darrell Henze
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102-1811
| | - György Buzsáki
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102-1811
| | - Peter Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom
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Baude A, Bleasdale C, Dalezios Y, Somogyi P, Klausberger T. Immunoreactivity for the GABAA receptor alpha1 subunit, somatostatin and Connexin36 distinguishes axoaxonic, basket, and bistratified interneurons of the rat hippocampus. Cereb Cortex 2007; 17:2094-107. [PMID: 17122364 DOI: 10.1093/cercor/bhl117] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Parvalbumin (PV)-expressing interneurons synchronize cortical neurons through gamma-aminobutyric acidergic (GABAergic) synapses. Three types of PV-containing interneurons populate stratum pyramidale of the hippocampal CA1 area: basket cells targeting somata and proximal dendrites, axoaxonic cells innervating axon initial segments, and bistratified cells targeting the dendrites of pyramidal cells. We tested whether this axonal specialization is accompanied by a differential expression of molecules involved in neuronal signaling. Immunofluorescence evaluation of interneurons labeled by neurobiotin in vivo shows that axoaxonic cells express significantly less GABA(A) receptor alpha1 subunit in the plasma membrane than basket and bistratified cells. Electron microscopic immunogold labeling reveals that this subunit contributes heavily to extrasynaptic receptors providing a substrate for tonic inhibition. Results from additional immunofluorescence experiments were consistent with the finding that only bistratified cells express the neuropeptide somatostatin. From the molecular profiles, we estimate that basket, bistratified, and axoaxonic cells represent about 60%, 25%, and 15%, respectively, of PV-containing cells in CA1 stratum pyramidale. In addition, all 3 interneuron classes form connexin36-immunopositive dendrodendritic gap junctions. The differential expression of signaling molecules and the relative frequency of cells reflect the specialized temporal contribution of the 3 types of PV-positive interneurons to GABA release in the network.
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Affiliation(s)
- Agnès Baude
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, UK
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Abstract
Cortical gamma oscillations contribute to cognitive processing and are thought to be supported by perisomatic-innervating GABAergic interneurons. We performed extracellular recordings of identified interneurons in the hippocampal CA1 area of anesthetized rats, revealing that the firing patterns of five distinct interneuron types are differentially correlated to spontaneous gamma oscillations. The firing of bistratified cells, which target dendrites of pyramidal cells coaligned with the glutamatergic input from hippocampal area CA3, is strongly phase locked to field gamma oscillations. Parvalbumin-expressing basket, axo-axonic, and cholecystokinin-expressing interneurons exhibit moderate gamma modulation, whereas the spike timing of distal dendrite-innervating oriens-lacunosum moleculare interneurons is not correlated to field gamma oscillations. Cholecystokinin-expressing interneurons fire earliest in the gamma cycle, a finding that is consistent with their suggested function of thresholding individual pyramidal cells. Furthermore, we show that field gamma amplitude correlates with interneuronal spike-timing precision and firing rate. Overall, our recordings suggest that gamma synchronization in vivo is assisted by temporal- and domain-specific GABAergic inputs to pyramidal cells and is initiated in pyramidal cell dendrites in addition to somata and axon initial segments.
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Affiliation(s)
- John J. Tukker
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Pablo Fuentealba
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Katja Hartwich
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
- Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Peter Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
- Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
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Wulff P, Goetz T, Leppä E, Linden AM, Renzi M, Swinny JD, Vekovischeva OY, Sieghart W, Somogyi P, Korpi ER, Farrant M, Wisden W. From synapse to behavior: rapid modulation of defined neuronal types with engineered GABAA receptors. Nat Neurosci 2007; 10:923-9. [PMID: 17572671 PMCID: PMC2092503 DOI: 10.1038/nn1927] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 05/22/2007] [Indexed: 11/09/2022]
Abstract
In mammals, identifying the contribution of specific neurons or networks to behavior is a key challenge. Here we describe an approach that facilitates this process by enabling the rapid modulation of synaptic inhibition in defined cell populations. Binding of zolpidem, a systemically active allosteric modulator that enhances the function of the GABAA receptor, requires a phenylalanine residue (Phe77) in the gamma2 subunit. Mice in which this residue is changed to isoleucine are insensitive to zolpidem. By Cre recombinase-induced swapping of the gamma2 subunit (that is, exchanging Ile77 for Phe77), zolpidem sensitivity can be restored to GABAA receptors in chosen cell types. We demonstrate the power of this method in the cerebellum, where zolpidem rapidly induces significant motor deficits when Purkinje cells are made uniquely sensitive to its action. This combined molecular and pharmacological technique has demonstrable advantages over targeted cell ablation and will be invaluable for investigating many neuronal circuits.
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Affiliation(s)
- Peer Wulff
- Department of Clinical Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany.
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Agid Y, Buzsáki G, Diamond DM, Frackowiak R, Giedd J, Girault JA, Grace A, Lambert JJ, Manji H, Mayberg H, Popoli M, Prochiantz A, Richter-Levin G, Somogyi P, Spedding M, Svenningsson P, Weinberger D. How can drug discovery for psychiatric disorders be improved? Nat Rev Drug Discov 2007; 6:189-201. [PMID: 17330070 DOI: 10.1038/nrd2217] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Psychiatric disorders such as depression, anxiety and schizophrenia are leading causes of disability worldwide, and have a huge societal impact. However, despite the clear need for better therapies, and major advances in the understanding of the molecular basis of these disorders in recent years, efforts to discover and develop new drugs for neuropsychiatric disorders, particularly those that might revolutionize disease treatment, have been relatively unsuccessful. A multidisciplinary approach will be crucial in addressing this problem, and in the first Advances in Neuroscience for Medical Innovation symposium, experts in multiple areas of neuroscience considered key questions in the field, in particular those related to the importance of neuronal plasticity. The discussions were used as a basis to propose steps that can be taken to improve the effectiveness of drug discovery for psychiatric disorders.
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Abstract
Long-term potentiation (LTP), which approximates Hebb's postulate of associative learning, typically requires depolarization-dependent glutamate receptors of the NMDA (N-methyl-D-aspartate) subtype. However, in some neurons, LTP depends instead on calcium-permeable AMPA-type receptors. This is paradoxical because intracellular polyamines block such receptors during depolarization. We report that LTP at synapses on hippocampal interneurons mediating feedback inhibition is "anti-Hebbian":Itis induced by presynaptic activity but prevented by postsynaptic depolarization. Anti-Hebbian LTP may occur in interneurons that are silent during periods of intense pyramidal cell firing, such as sharp waves, and lead to their altered activation during theta activity.
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Affiliation(s)
- Karri P. Lamsa
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Joost H. Heeroma
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Peter Somogyi
- Anatomical Neuropharmacology Unit, Medical Research Council, Oxford University, Mansfield Road, Oxford OXI 3HT, UK
| | - Dmitri A. Rusakov
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Dimitri M. Kullmann
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
- To whom correspondence should be addressed.
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Klausberger T, Márton L, Baude A, Roberts JDB, Magill PJ, Somogyi P. Erratum: Corrigendum: Spike timing of dendrite-targeting bistratified cells during hippocampal network oscillations in vivo. Nat Neurosci 2006. [DOI: 10.1038/nn0706-979a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Klausberger T, Marton LF, O'Neill J, Huck JHJ, Dalezios Y, Fuentealba P, Suen WY, Papp E, Kaneko T, Watanabe M, Csicsvari J, Somogyi P. Complementary roles of cholecystokinin- and parvalbumin-expressing GABAergic neurons in hippocampal network oscillations. J Neurosci 2006; 25:9782-93. [PMID: 16237182 PMCID: PMC6725722 DOI: 10.1523/jneurosci.3269-05.2005] [Citation(s) in RCA: 324] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the hippocampal CA1 area, a relatively homogenous population of pyramidal cells is accompanied by a diversity of GABAergic interneurons. Previously, we found that parvalbumin-expressing basket, axo-axonic, bistratified, and oriens-lacunosum moleculare cells, innervating different domains of pyramidal cells, have distinct firing patterns during network oscillations in vivo. A second family of interneurons, expressing cholecystokinin but not parvalbumin, is known to target the same domains of pyramidal cells as do the parvalbumin cells. To test the temporal activity of these independent and parallel GABAergic inputs, we recorded the precise spike timing of identified cholecystokinin interneurons during hippocampal network oscillations in anesthetized rats and determined their molecular expression profiles and synaptic targets. The cells were cannabinoid receptor type 1 immunopositive. Contrary to the stereotyped firing of parvalbumin interneurons, cholecystokinin-expressing basket and dendrite-innervating cells discharge, on average, with 1.7 +/- 2.0 Hz during high-frequency ripple oscillations in an episode-dependent manner. During theta oscillations, cholecystokinin-expressing interneurons fire with 8.8 +/- 3.3 Hz at a characteristic time on the ascending phase of theta waves (155 +/- 81 degrees), when place cells start firing in freely moving animals. The firing patterns of some interneurons recorded in drug-free behaving rats were similar to cholecystokinin cells in anesthetized animals. Our results demonstrate that cholecystokinin- and parvalbumin-expressing interneurons make different contributions to network oscillations and play distinct roles in different brain states. We suggest that the specific spike timing of cholecystokinin interneurons and their sensitivity to endocannabinoids might contribute to differentiate subgroups of pyramidal cells forming neuronal assemblies, whereas parvalbumin interneurons contribute to synchronizing the entire network.
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Affiliation(s)
- Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom.
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Ferraguti F, Klausberger T, Cobden P, Baude A, Roberts JDB, Szucs P, Kinoshita A, Shigemoto R, Somogyi P, Dalezios Y. Metabotropic glutamate receptor 8-expressing nerve terminals target subsets of GABAergic neurons in the hippocampus. J Neurosci 2006; 25:10520-36. [PMID: 16280590 PMCID: PMC6725819 DOI: 10.1523/jneurosci.2547-05.2005] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Presynaptic metabotropic glutamate receptors (mGluRs) show a highly selective expression and subcellular location in nerve terminals modulating neurotransmitter release. We have demonstrated that alternatively spliced variants of mGluR8, mGluR8a and mGluR8b, have an overlapping distribution in the hippocampus, and besides perforant path terminals, they are expressed in the presynaptic active zone of boutons making synapses selectively with several types of GABAergic interneurons, primarily in the stratum oriens. Boutons labeled for mGluR8 formed either type I or type II synapses, and the latter were GABAergic. Some mGluR8-positive boutons also expressed mGluR7 or vasoactive intestinal polypeptide. Interneurons strongly immunopositive for the muscarinic M2 or the mGlu1 receptors were the primary targets of mGluR8-containing terminals in the stratum oriens, but only neurochemically distinct subsets were innervated by mGluR8-enriched terminals. The majority of M2-positive neurons were mGluR8 innervated, but a minority, which expresses somatostatin, was not. Rare neurons coexpressing calretinin and M2 were consistently targeted by mGluR8-positive boutons. In vivo recording and labeling of an mGluR8-decorated and strongly M2-positive interneuron revealed a trilaminar cell with complex spike bursts during theta oscillations and strong discharge during sharp wave/ripple events. The trilaminar cell had a large projection from the CA1 area to the subiculum and a preferential innervation of interneurons in the CA1 area in addition to pyramidal cell somata and dendrites. The postsynaptic interneuron type-specific expression of the high-efficacy presynaptic mGluR8 in both putative glutamatergic and in identified GABAergic terminals predicts a role in adjusting the activity of interneurons depending on the level of network activity.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Oxford University, Oxford OX1 3TH, United Kingdom.
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Cope DW, Halbsguth C, Karayannis T, Wulff P, Ferraguti F, Hoeger H, Leppä E, Linden AM, Oberto A, Ogris W, Korpi ER, Sieghart W, Somogyi P, Wisden W, Capogna M. Loss of zolpidem efficacy in the hippocampus of mice with the GABAA receptor gamma2 F77I point mutation. Eur J Neurosci 2005; 21:3002-16. [PMID: 15978011 DOI: 10.1111/j.1460-9568.2005.04127.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zolpidem is a hypnotic benzodiazepine site agonist with some gamma-aminobutyric acid (GABA)(A) receptor subtype selectivity. Here, we have tested the effects of zolpidem on the hippocampus of gamma2 subunit (gamma2F77I) point mutant mice. Analysis of forebrain GABA(A) receptor expression with immunocytochemistry, quantitative [(3)H]muscimol and [(35)S] t-butylbicyclophosphorothionate (TBPS) autoradiography, membrane binding with [(3)H]flunitrazepam and [(3)H]muscimol, and comparison of miniature inhibitory postsynaptic current (mIPSC) parameters did not reveal any differences between homozygous gamma2I77/I77 and gamma2F77/F77 mice. However, quantitative immunoblot analysis of gamma2I77/I77 hippocampi showed some increased levels of gamma2, alpha1, alpha4 and delta subunits, suggesting that differences between strains may exist in unassembled subunit levels, but not in assembled receptors. Zolpidem (1 microm) enhanced the decay of mIPSCs in CA1 pyramidal cells of control (C57BL/6J, gamma2F77/F77) mice by approximately 60%, and peak amplitude by approximately 20% at 33-34 degrees C in vitro. The actions of zolpidem (100 nm or 1 microm) were substantially reduced in gamma2I77/I77 mice, although residual effects included a 9% increase in decay and 5% decrease in peak amplitude. Similar results were observed in CA1 stratum oriens/alveus interneurons. At network level, the effect of zolpidem (10 microm) on carbachol-induced oscillations in the CA3 area of gamma2I77/I77 mice was significantly different compared with controls. Thus, the gamma2F77I point mutation virtually abolished the actions of zolpidem on GABA(A) receptors in the hippocampus. However, some residual effects of zolpidem may involve receptors that do not contain the gamma2 subunit.
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Affiliation(s)
- D W Cope
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Mansfield Road, Oxford OX1 3TH, UK.
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Lin SC, Huck JHJ, Roberts JDB, Macklin WB, Somogyi P, Bergles DE. Climbing Fiber Innervation of NG2-Expressing Glia in the Mammalian Cerebellum. Neuron 2005; 46:773-85. [PMID: 15924863 DOI: 10.1016/j.neuron.2005.04.025] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Revised: 04/04/2005] [Accepted: 04/20/2005] [Indexed: 10/25/2022]
Abstract
The molecular layer of the cerebellar cortex is populated by glial progenitors that express ionotropic glutamate receptors and extend numerous processes among Purkinje cell dendrites. Here, we show that release of glutamate from climbing fiber (CF) axons produces AMPA receptor currents with rapid kinetics in these NG2-immunoreactive glial cells (NG2+ cells) in cerebellar slices. NG2+ cells may receive up to 70 discrete inputs from one CF and, unlike mature Purkinje cells, are often innervated by multiple CFs. Paired Purkinje cell-NG2+ cell recordings show that one CF can innervate both cell types. CF boutons make direct synaptic junctions with NG2+ cell processes, indicating that this rapid neuron-glia signaling occurs at discrete sites rather than through ectopic release at CF-Purkinje cell synapses. This robust activation of Ca2+-permeable AMPA receptors in NG2+ cells expands the influence of the olivocerebellar projection to this abundant class of glial progenitors.
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Affiliation(s)
- Shih-Chun Lin
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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40
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Abstract
Correlated activity of cortical neurons underlies cognitive processes. Networks of several distinct classes of gamma-aminobutyric acid (GABA)ergic interneurons are capable of synchronizing cortical neurons at behaviourally relevant frequencies. Here we show that perisomatic and dendritic GABAergic inputs provided by two classes of GABAergic cells, fast spiking and bitufted interneurons, respectively, entrain the timing of postsynaptic spikes differentially in both pyramidal cells and interneurons at beta and gamma frequencies. Entrainment of pyramidal as well as regular spiking non-pyramidal cells was input site and inhibitory postsynaptic potential frequency dependent. Gamma frequency input from fast spiking cells entrained pyramidal cells on the positive phase of an intrinsic cellular theta oscillation, whereas input from bitufted cells was most effective in gamma frequency entrainment on the negative phase of the theta oscillation. The discharge of regular spiking interneurons was phased at gamma frequency by dendritic input from bitufted cells, but not by perisomatic input from fast spiking cells. Action potentials in fast spiking GABAergic neurons were phased at gamma frequency by both other fast spiking and bitufted cells, regardless of whether the presynaptic GABAergic input was at gamma or beta frequency. The interaction of cell type-specific intrinsic properties and location-selective GABAergic inputs could result in a spatio-temporally regulated synchronization and gating of cortical spike propagation in the network.
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Affiliation(s)
- Gábor Tamás
- Department of Comparative Physiology, University of Szeged, Közép fasor 52, Szeged H-6726, Hungary.
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41
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Abstract
The cerebral cortex encodes, stores and combines information about the internal and external environment in rhythmic activity of multiple frequency ranges. Neurones of the cortex can be defined, recognized and compared on the comprehensive application of the following measures: (i) brain area- and cell domain-specific distribution of input and output synapses, (ii) expression of molecules involved in cell signalling, (iii) membrane and synaptic properties reflecting the expression of membrane proteins, (iv) temporal structure of firing in vivo, resulting from (i)-(iii). Spatial and temporal measures of neurones in the network reflect an indivisible unity of evolutionary design, i.e. neurones do not have separate structure or function. The blueprint of this design is most easily accessible in the CA1 area of the hippocampus, where a relatively uniform population of pyramidal cells and their inputs follow an instantly recognizable laminated pattern and act within stereotyped network activity patterns. Reviewing the cell types and their spatio-temporal interactions, we suggest that CA1 pyramidal cells are supported by at least 16 distinct types of GABAergic neurone. During a given behaviour-contingent network oscillation, interneurones of a given type exhibit similar firing patterns. During different network oscillations representing two distinct brain states, interneurones of the same class show different firing patterns modulating their postsynaptic target-domain in a brain-state-dependent manner. These results suggest roles for specific interneurone types in structuring the activity of pyramidal cells via their respective target domains, and accurately timing and synchronizing pyramidal cell discharge, rather than providing generalized inhibition. Finally, interneurones belonging to different classes may fire preferentially at distinct time points during a given oscillation. As different interneurones innervate distinct domains of the pyramidal cells, the different compartments will receive GABAergic input differentiated in time. Such a dynamic, spatio-temporal, GABAergic control, which evolves distinct patterns during different brain states, is ideally suited to regulating the input integration of individual pyramidal cells contributing to the formation of cell assemblies and representations in the hippocampus and, probably, throughout the cerebral cortex.
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Affiliation(s)
- Peter Somogyi
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
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42
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Cope DW, Wulff P, Oberto A, Aller MI, Capogna M, Ferraguti F, Halbsguth C, Hoeger H, Jolin HE, Jones A, McKenzie ANJ, Ogris W, Poeltl A, Sinkkonen ST, Vekovischeva OY, Korpi ER, Sieghart W, Sigel E, Somogyi P, Wisden W. Abolition of zolpidem sensitivity in mice with a point mutation in the GABAA receptor gamma2 subunit. Neuropharmacology 2004; 47:17-34. [PMID: 15165831 DOI: 10.1016/j.neuropharm.2004.03.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 02/03/2004] [Accepted: 03/01/2004] [Indexed: 11/24/2022]
Abstract
Agonists of the allosteric benzodiazepine site of GABAA receptors bind at the interface of the alpha and gamma subunits. Here, we tested the in vivo contribution of the gamma2 subunit to the actions of zolpidem, an alpha1 subunit selective benzodiazepine agonist, by generating mice with a phenylalanine (F) to isoleucine (I) substitution at position 77 in the gamma2 subunit. The gamma2F77I mutation has no major effect on the expression of GABAA receptor subunits in the cerebellum. The potency of zolpidem, but not that of flurazepam, for the inhibition of [3H]flunitrazepam binding to cerebellar membranes is greatly reduced in gamma2I77/I77 mice. Zolpidem (1 microM) increased both the amplitude and decay of miniature inhibitory postsynaptic currents (mIPSCs) in Purkinje cells of control C57BL/6 (34% and 92%, respectively) and gamma2F77/F77 (20% and 84%) mice, but not in those of gamma2F77I mice. Zolpidem tartrate had no effect on exploratory activity (staircase test) or motor performance (rotarod test) in gamma2I77/I77 mice at doses up to 30 mg/kg (i.p.) that strongly sedated or impaired the control mice. Flurazepam was equally effective in enhancing mIPSCs and disrupting performance in the rotarod test in control and gamma2I77/I77 mice. These results show that the effect of zolpidem, but not flurazepam, is selectively eliminated in the brain by the gamma2F77I point mutation.
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Affiliation(s)
- D W Cope
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Mansfield Road, Oxford OX1 3TH, UK.
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Kogo N, Dalezios Y, Capogna M, Ferraguti F, Shigemoto R, Somogyi P. Depression of GABAergic input to identified hippocampal neurons by group III metabotropic glutamate receptors in the rat. Eur J Neurosci 2004; 19:2727-40. [PMID: 15147307 DOI: 10.1111/j.0953-816x.2004.03394.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The release of GABA in synapses is modulated by presynaptic metabotropic glutamate receptors (mGluRs). We tested whether GABA release to identified hippocampal neurons is influenced by group III mGluR activation using the agonist L-(+)-2-amino-4-phosphonobutyric acid (L-AP4) on inhibitory postsynaptic currents (IPSCs) evoked in CA1 interneurons and pyramidal cells. In interneurons, characterized with biocytin and immunolabelling for somatostatin, evoked IPSCs were depressed by 50 micro m L-AP4 (activating mGluR4 and 8) to 68 +/- 6% of control, but they were rarely depressed in pyramidal cells (96 +/- 4% of control). At 300-500 micro m concentration (activating mGluR4, 7 and 8), L-AP4 depressed IPSCs in both interneurons (to 70 +/- 6%) and pyramidal cells (to 67 +/- 4%). The change in trial-to-trial variability and in paired-pulse depression indicated a presynaptic action. In interneurons, the degree of IPSC depression was variable (to 9-87%), and a third of IPSCs were not affected by L-AP4. The L-AP4-evoked IPSC depression was blocked by LY341495. The depression of IPSCs was similar in O-LM cells and other interneurons. The lack of cell-type selectivity and the similar efficacy of different concentrations of L-AP4 suggest that several group III mGluRs are involved in the depression of IPSCs. Electron microscopic immunocytochemistry confirmed that mGluR4, mGluR7a and mGluR8a occur in the presynaptic active zone of GABAergic terminals on interneurons, but not on those innervating pyramidal cells. The high variability of L-AP4-evoked IPSC suppression is in line with the selective expression of presynaptic mGluRs by several distinct types of GABAergic neuron innervating each interneuron type.
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Affiliation(s)
- Naoki Kogo
- Medical Research Council, Anatomical Neuropharmacology Unit, University Department of Pharmacology, Mansfield Road, Oxford, UK
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Ganter P, Szücs P, Paulsen O, Somogyi P. Properties of horizontal axo-axonic cells in stratum oriens of the hippocampal CA1 area of rats in vitro. Hippocampus 2004; 14:232-43. [PMID: 15098728 DOI: 10.1002/hipo.10170] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Local-circuit gamma-aminobutyric acid (GABA)ergic interneurons constitute a diverse population of cells, which remain poorly defined into functionally distinct subclasses. Traditionally, dendritic and axonal arbors have been used to describe cell classes. In the present report, we characterize a set of hippocampal interneurons, horizontal axo-axonic cells, located in stratum oriens. They displayed the pattern of axonal arborization characteristic of axo-axonic cells with radially aligned rows of boutons making synapses exclusively on axon initial segments of pyramidal cells, as shown by electron microscopy. However, in contrast to previously described axo-axonic cells, which have radial dendrites spanning all layers, the dendrites of the horizontal axo-axonic cells were restricted to stratum oriens and ran parallel with the layers for several hundred micrometers. Single action potentials elicited by depolarizing current steps in these cells were often followed by a fast- and medium-duration afterhyperpolarization, distinguishing them from fast-spiking interneurons. In two out of four cells, trains of action potentials showed prominent early spike frequency adaptation and a characteristic "accommodative hump." Excitatory postsynaptic potentials (EPSPs) could be evoked by stimuli delivered to stratum oriens. Paired recordings unequivocally confirmed direct synaptic inputs from CA1 pyramidal cells. The kinetics of the EPSPs were fast (rise time 1.7 +/- 0.6 ms, mean +/- SD, n = 3; decay time constant 19.3 +/- 2.4 ms). They showed paired-pulse depression with inter-stimulus intervals of 10-50 ms. One pair showed a reciprocal connection establishing a direct feedback loop. The axo-axonic cell-evoked inhibitory postsynaptic potentials (IPSPs) were reliable (failure rate approximately 10%). Our data show that the laminar distribution of the dendrites of axo-axonic cells can vary, suggesting distinct synaptic inputs. However, this remains to be shown directly, and we cannot exclude the possibility that all axo-axonic cells may gather similar synaptic input, leaving them as one distinct class of interneuron.
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Affiliation(s)
- Paul Ganter
- MRC Anatomical Neuropharmacology Unit, Oxford University, United Kingdom.
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Somogyi J, Baude A, Omori Y, Shimizu H, El Mestikawy S, Fukaya M, Shigemoto R, Watanabe M, Somogyi P. GABAergic basket cells expressing cholecystokinin contain vesicular glutamate transporter type 3 (VGLUT3) in their synaptic terminals in hippocampus and isocortex of the rat. Eur J Neurosci 2004; 19:552-69. [PMID: 14984406 DOI: 10.1111/j.0953-816x.2003.03091.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vesicular glutamate transporter type 3 (VGLUT3) containing neuronal elements were characterized using antibodies to VGLUT3 and molecular cell markers. All VGLUT3-positive somata were immunoreactive for CCK, and very rarely, also for calbindin; none was positive for parvalbumin, calretinin, VIP or somatostatin. In the CA1 area, 26.8 +/- 0.7% of CCK-positive interneuron somata were VGLUT3-positive, a nonoverlapping 22.8 +/- 1.9% were calbindin-positive, 10.7 +/- 2.5% VIP-positive and the rest were only CCK-positive. The patterns of coexpression were similar in the CA3 area, the dentate gyrus and the isocortex. Immunoreactivity for VGLUT3 was undetectable in pyramidal and dentate granule cells. Boutons colabelled for VGLUT3, CCK and GAD were most abundant in the cellular layers of the hippocampus and in layers II-III of the isocortex. Large VGLUT3-labelled boutons at the border of strata radiatum and lacunosum-moleculare in the CA1 area were negative for GAD, but were labelled for vesicular monoamine transporter type 2, plasmalemmal serotonin transporter or serotonin. No colocalization was found in terminals between VGLUT3 and parvalbumin, vesicular acetylcholine transporter and group III (mGluR7a,b; mGluR8a,b) metabotropic glutamate receptors. In stratum radiatum and the isocortex, VGLUT3-positive but GAD-negative boutons heavily innervated the soma and proximal dendrites of some VGLUT3- or calbindin-positive interneurons. The results suggest that boutons coexpressing VGLUT3, CCK and GAD originate from CCK-positive basket cells, which are VIP-immunonegative. Other VGLUT3-positive boutons immunopositive for serotonergic markers but negative for GAD probably originate from the median raphe nucleus and innervate select interneurons. The presumed amino acid substrate of VGLUT3 may act on presynaptic kainate or group II metabotropic glutamate receptors.
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Affiliation(s)
- Jozsef Somogyi
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford OX1 3TH, UK.
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46
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Ferraguti F, Cobden P, Pollard M, Cope D, Shigemoto R, Watanabe M, Somogyi P. Immunolocalization of metabotropic glutamate receptor 1? (mGluR1?) in distinct classes of interneuron in the CA1 region of the rat hippocampus. Hippocampus 2004; 14:193-215. [PMID: 15098725 DOI: 10.1002/hipo.10163] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In the hippocampal CA1 region, metabotropic glutamate subtype 1 (mGluR1) receptors have been implicated in a variety of physiological responses to glutamate, which include modulation of synaptic transmission and plasticity, as well as neuronal excitability and synchronization. The mGluR1alpha isoform is characteristically expressed only by nonprincipal cells, and it is particularly enriched in somatostatin (SS)-containing interneurons in stratum oriensalveus. Anatomical and physiological data have indicated the presence of mGluR1alpha in several distinct classes of interneurons with their somata located also in strata pyramidale, radiatum, and lacunosum moleculare. Each different interneuron subtype, as defined by functionally relevant criteria, including input/ output characteristics and expression of selective molecular markers, subserves distinct functions in local hippocampal circuits. We have investigated which of the different CA1 interneuron classes express mGluR1alpha by immunofluorescent labeling, combining antibodies to mGluR1alpha, calcium-binding proteins, and neuropeptides, and by intracellular labeling in vitro. Several types of interneuron that are immunopositive for mGluR1alpha each targeted different domains of pyramidal cells and included (1) O-LM inter-neurons, found to coexpress both SS and parvalbumin (PV); (2) interneurons with target selectivity for other interneurons, expressing vasoactive intestinal polypeptide (VIP) and/or the calcium-binding protein calretinin; (3) procholecystokinin-immunopositive interneurons probably non-basket and dendrite-targeting; and (4) an as-yet unidentified SS-immunoreactive but PV-immunonegative interneuron class, possibly corresponding to oriens-bistratified cells. Estimation of the relative proportion of mGluR1alpha-positive interneurons showed 43%, 46%, and 30% co-labeling with SS, VIP, or PV, respectively. The identification of the specific subclasses of CA1 interneurons expressing mGluR1alpha provides the network basis for assessing the contribution of this receptor to the excitability of the hippocampus.
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Affiliation(s)
- Francesco Ferraguti
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Mansfield Road, OX1 3TH Oxford, UK.
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Kaszanyitzky EJ, Egyed Z, Jánosi S, Keseru J, Gál Z, Szabó I, Veres Z, Somogyi P. Staphylococci isolated from animals and food with phenotypically reduced susceptibility to beta-lactamase-resistant beta-lactam antibiotics. Acta Vet Hung 2004; 52:7-17. [PMID: 15119783 DOI: 10.1556/avet.52.2004.1.2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The antibiotic resistance pattern of 1921 Staphylococcus strains isolated from animals and food within the last two years were examined using diffusion tests. Among them there were only 35 strains of S. aureus having an inhibition zone diameter of 15 mm or less, and 4 strains of coagulase-negative staphylococci (CNS) having a zone diameter of 18 mm or less to 1-microg oxacillin disk. These 39 strains were examined also by E-test to oxacillin and for the detection of the mecA gene by PCR in order to determine whether they might be real methicillin-resistant staphylococci. Among the 39 strains there were only two that were susceptible to penicillin by disk diffusion method; however, further examination by the penicillinase test showed that they produced beta-lactamase. While 19 (15 S. aureus, 4 CNS) strains were resistant and 7 strains were intermediate to oxacillin in disk diffusion test, the E-test gave 8 resistant and 5 intermediate results. Six out of the 8 oxacillin-resistant strains examined by disk diffusion and E-test harboured the mecA gene. Thus only 6 out of the examined 1921 strains proved to be mecA positive. These methicillin-resistant, mecA-positive strains (5 of the S. aureus strains and 1 of the S. epidermidis) originated from two dairy herds. The results prove that methicillin-resistant S. aureus (MRSA) strains in animals are really rare in Hungary. Eighteen strains were chosen and screened for minimal inhibitory concentration (MIC) of oxacillin with or without clavulanic acid or sulbactam, and three of them produced methicillinase enzyme.
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Klausberger T, Márton LF, Baude A, Roberts JDB, Magill PJ, Somogyi P. Spike timing of dendrite-targeting bistratified cells during hippocampal network oscillations in vivo. Nat Neurosci 2003; 7:41-7. [PMID: 14634650 DOI: 10.1038/nn1159] [Citation(s) in RCA: 266] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 11/05/2003] [Indexed: 11/08/2022]
Abstract
Behavior-contingent network oscillations bring about transient, functionally coherent neuronal assemblies in the cerebral cortex, including the hippocampus. Inhibitory input on and close to the soma is believed to phase intrinsic oscillations and output of pyramidal cells, but the function of GABA release to pyramidal cell dendrites remains unknown. We recorded the oscillation-locked spike timing of identified bistratified interneurons in rats. These cells mainly innervated small dendritic shafts of pyramidal cells co-aligned with the glutamatergic Schaffer collateral/commissural input. During theta oscillations, bistratified cells fired at a phase when, on average, pyramidal cell dendrites are most hyperpolarized. Interneurons targeting the perisomatic domain discharge at an earlier phase. During sharp wave-associated ripples, bistratified cells fired with high frequency and in-phase with basket cells, on average 1-2 ms after the discharges in pyramidal cell somata and dendrites. Our results indicate that bistratified cells rhythmically modulate glutamatergic input to the dendrites of pyramidal cells to actively promote the precise input/output transformation during network oscillations.
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Affiliation(s)
- Thomas Klausberger
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Mansfield Road, Oxford OX1 3TH, UK.
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Nyíri G, Stephenson FA, Freund TF, Somogyi P. Large variability in synaptic N-methyl-D-aspartate receptor density on interneurons and a comparison with pyramidal-cell spines in the rat hippocampus. Neuroscience 2003; 119:347-63. [PMID: 12770551 DOI: 10.1016/s0306-4522(03)00157-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Pyramidal cells receive input from several types of GABA-releasing interneurons and innervate them reciprocally. Glutamatergic activation of interneurons involves both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) type glutamate receptors expressed in type I synapses, mostly on their dendritic shafts. On average, the synaptic AMPA receptor content is several times higher on interneurons than in the spines of pyramidal cells. To compare the NMDA receptor content of synapses, we used a quantitative postembedding immunogold technique on serial electron microscopic sections, and analysed the synapses on interneuron dendrites and pyramidal cell spines in the CA1 area. Because all NMDA receptors contain the obligatory NR1 subunit, receptor localisation was carried out using antibodies recognising all splice variants of the NR1 subunit. Four populations of synapse were examined: i). on spines of pyramidal cells in stratum (str.) radiatum and str. oriens; ii). on parvalbumin-positive interneuronal dendritic shafts in str. radiatum; iii). on randomly found dendritic shafts in str. oriens and iv). on somatostatin-positive interneuronal dendritic shafts and somata in str. oriens. On average, the size of the synapses on spines was about half of those on interneurons. The four populations of synapse significantly differed in labelling for the NR1 subunit. The median density of NR1 subunit labelling was highest on pyramidal cell spines. It was lowest in the synapses on parvalbumin-positive dendrites in str. radiatum, where more than half of these synapses were immunonegative. In str. oriens, synapses on interneurons had a high variability of receptor content; some dendrites were similar to those in str. radiatum, including the proximal synapses of somatostatin-positive cells, whereas others had immunoreactivity for the NR1 subunit similar to or higher than synapses on pyramidal cell spines. These results show that synaptic NMDA receptor density differs between pyramidal cells and interneurons. Some interneurons may have a high NMDA receptor content, whereas others, like some parvalbumin-expressing cells, a particularly low synaptic NMDA receptor content. Consequently, fast glutamatergic activation of interneurons is expected to show cell type-specific time course and state-dependent dynamics.
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Affiliation(s)
- G Nyíri
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, PO Box 37, H-1450, Hungary.
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Somogyi P, Dalezios Y, Luján R, Roberts JDB, Watanabe M, Shigemoto R. High level of mGluR7 in the presynaptic active zones of select populations of GABAergic terminals innervating interneurons in the rat hippocampus. Eur J Neurosci 2003; 17:2503-20. [PMID: 12823458 DOI: 10.1046/j.1460-9568.2003.02697.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The release of neurotransmitters is modulated by presynaptic metabotropic glutamate receptors (mGluRs), which show a highly selective expression and subcellular location in glutamatergic terminals in the hippocampus. Using immunocytochemistry, we investigated whether one of the receptors, mGluR7, whose level of expression is governed by the postsynaptic target, was present in GABAergic terminals and whether such terminals targeted particular cells. A total of 165 interneuron dendritic profiles receiving 466 synapses (82% mGluR7a-positive) were analysed. The presynaptic active zones of most GAD-(77%) or GABA-positive (94%) synaptic boutons on interneurons innervated by mGluR7a-enriched glutamatergic terminals (mGluR7a-decorated) were immunopositive for mGluR7a. GABAergic terminals on pyramidal cells and most other interneurons in str. oriens were mGluR7a-immunonegative. The mGluR7a-decorated cells were mostly somatostatin- and mGluR1alpha-immunopositive neurons in str. oriens and the alveus. Their GABAergic input mainly originated from VIP-positive terminals, 90% of which expressed high levels of mGluR7a in the presynaptic active zone. Parvalbumin-positive synaptic terminals were rare on mGluR7a-decorated cells, but on these neurons 73% of them were mGluR7a-immunopositive. Some type II synapses innervating interneurons were immunopositive for mGluR7b, as were some type I synapses. Because not all target cells of VIP-positive neurons are known it has not been possible to determine whether mGluR7 is expressed in a target-cell-specific manner in the terminals of single GABAergic cells. The activation of mGluR7 may decrease GABA release to mGluR7-decorated cells at times of high pyramidal cell activity, which elevates extracellular glutamate levels. Alternatively, the presynaptic receptor may be activated by as yet unidentified endogenous ligands released by the GABAergic terminals or the postsynaptic dendrites.
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Affiliation(s)
- Peter Somogyi
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Mansfield Road, Oxford University, Oxford OX1 3TH, UK.
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