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Kaufhold D, Maristany de Las Casas E, Ocaña-Fernández MDÁ, Cazala A, Yuan M, Kulik A, Cholvin T, Steup S, Sauer JF, Eyre MD, Elgueta C, Strüber M, Bartos M. Spine plasticity of dentate gyrus parvalbumin-positive interneurons is regulated by experience. Cell Rep 2024; 43:113806. [PMID: 38377001 DOI: 10.1016/j.celrep.2024.113806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Experience-driven alterations in neuronal activity are followed by structural-functional modifications allowing cells to adapt to these activity changes. Structural plasticity has been observed for cortical principal cells. However, how GABAergic interneurons respond to experience-dependent network activity changes is not well understood. We show that parvalbumin-expressing interneurons (PVIs) of the dentate gyrus (DG) possess dendritic spines, which undergo behaviorally induced structural dynamics. Glutamatergic inputs at PVI spines evoke signals with high spatial compartmentalization defined by neck length. Mice experiencing novel contexts form more PVI spines with elongated necks and exhibit enhanced network and PVI activity and cFOS expression. Enhanced green fluorescent protein reconstitution across synaptic partner-mediated synapse labeling shows that experience-driven PVI spine growth boosts targeting of PVI spines over shafts by glutamatergic synapses. Our findings propose a role for PVI spine dynamics in regulating PVI excitation by their inputs, which may allow PVIs to dynamically adjust their functional integration in the DG microcircuitry in relation to network computational demands.
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Affiliation(s)
- Dorthe Kaufhold
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | | | | | - Aurore Cazala
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mei Yuan
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Akos Kulik
- Institute of Physiology II, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Thibault Cholvin
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Stefanie Steup
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Jonas-Frederic Sauer
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mark D Eyre
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Claudio Elgueta
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Michael Strüber
- Epilepsy Center Frankfurt Rhine-Main, Center of Neurology and Neurosurgery, Goethe University, 60528 Frankfurt am Main, Germany
| | - Marlene Bartos
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
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2
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Muysers H, Chen HL, Hahn J, Folschweiller S, Sigurdsson T, Sauer JF, Bartos M. A persistent prefrontal reference frame across time and task rules. Nat Commun 2024; 15:2115. [PMID: 38459033 PMCID: PMC10923947 DOI: 10.1038/s41467-024-46350-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/22/2024] [Indexed: 03/10/2024] Open
Abstract
Behavior can be remarkably consistent, even over extended time periods, yet whether this is reflected in stable or 'drifting' neuronal responses to task features remains controversial. Here, we find a persistently active ensemble of neurons in the medial prefrontal cortex (mPFC) of mice that reliably maintains trajectory-specific tuning over several weeks while performing an olfaction-guided spatial memory task. This task-specific reference frame is stabilized during learning, upon which repeatedly active neurons show little representational drift and maintain their trajectory-specific tuning across long pauses in task exposure and across repeated changes in cue-target location pairings. These data thus suggest a 'core ensemble' of prefrontal neurons forming a reference frame of task-relevant space for the performance of consistent behavior over extended periods of time.
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Affiliation(s)
- Hannah Muysers
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany
| | - Hung-Ling Chen
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany
| | - Johannes Hahn
- Institute of Neurophysiology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Shani Folschweiller
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany
- Sleep-Wake-Epilepsy Center and Center for Experimental Neurology, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jonas-Frederic Sauer
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany.
| | - Marlene Bartos
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany.
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3
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Hainmueller T, Cazala A, Huang LW, Bartos M. Subfield-specific interneuron circuits govern the hippocampal response to novelty in male mice. Nat Commun 2024; 15:714. [PMID: 38267409 PMCID: PMC10808551 DOI: 10.1038/s41467-024-44882-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024] Open
Abstract
The hippocampus is the brain's center for episodic memories. Its subregions, the dentate gyrus and CA1-3, are differentially involved in memory encoding and recall. Hippocampal principal cells represent episodic features like movement, space, and context, but less is known about GABAergic interneurons. Here, we performed two-photon calcium imaging of parvalbumin- and somatostatin-expressing interneurons in the dentate gyrus and CA1-3 of male mice exploring virtual environments. Parvalbumin-interneurons increased activity with running-speed and reduced it in novel environments. Somatostatin-interneurons in CA1-3 behaved similar to parvalbumin-expressing cells, but their dentate gyrus counterparts increased activity during rest and in novel environments. Congruently, chemogenetic silencing of dentate parvalbumin-interneurons had prominent effects in familiar contexts, while silencing somatostatin-expressing cells increased similarity of granule cell representations between novel and familiar environments. Our data indicate unique roles for parvalbumin- and somatostatin-positive interneurons in the dentate gyrus that are distinct from those in CA1-3 and may support routing of novel information.
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Affiliation(s)
- Thomas Hainmueller
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany.
- NYU Neuroscience Institute, 435 East 30th Street, New York, NY, 10016, USA.
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.
| | - Aurore Cazala
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany
| | - Li-Wen Huang
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany.
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4
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Sylte OC, Muysers H, Chen HL, Bartos M, Sauer JF. Neuronal tuning to threat exposure remains stable in the mouse prefrontal cortex over multiple days. PLoS Biol 2024; 22:e3002475. [PMID: 38206890 PMCID: PMC10783789 DOI: 10.1371/journal.pbio.3002475] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Received: 06/28/2023] [Accepted: 12/19/2023] [Indexed: 01/13/2024] Open
Abstract
Intense threat elicits action in the form of active and passive coping. The medial prefrontal cortex (mPFC) executes top-level control over the selection of threat coping strategies, but the dynamics of mPFC activity upon continuing threat encounters remain unexplored. Here, we used 1-photon calcium imaging in mice to probe the activity of prefrontal pyramidal cells during repeated exposure to intense threat in a tail suspension (TS) paradigm. A subset of prefrontal neurons displayed selective activation during TS, which was stably maintained over days. During threat, neurons showed specific tuning to active or passive coping. These responses were unrelated to general motion tuning and persisted over days. Moreover, the neural manifold traversed by low-dimensional population activity remained stable over subsequent days of TS exposure and was preserved across individuals. These data thus reveal a specific, temporally, and interindividually conserved repertoire of prefrontal tuning to behavioral responses under threat.
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Affiliation(s)
- Ole Christian Sylte
- University of Freiburg, Medical Faculty, Institute of Physiology I, Freiburg, Germany
- University of Freiburg, Faculty of Biology, Freiburg, Germany
| | - Hannah Muysers
- University of Freiburg, Medical Faculty, Institute of Physiology I, Freiburg, Germany
- University of Freiburg, Faculty of Biology, Freiburg, Germany
| | - Hung-Ling Chen
- University of Freiburg, Medical Faculty, Institute of Physiology I, Freiburg, Germany
| | - Marlene Bartos
- University of Freiburg, Medical Faculty, Institute of Physiology I, Freiburg, Germany
| | - Jonas-Frederic Sauer
- University of Freiburg, Medical Faculty, Institute of Physiology I, Freiburg, Germany
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5
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Grigoryan G, Harada H, Knobloch-Bollmann HS, Kilias A, Kaufhold D, Kulik A, Eyre MD, Bartos M. Synaptic plasticity at the dentate gyrus granule cell to somatostatin-expressing interneuron synapses supports object location memory. Proc Natl Acad Sci U S A 2023; 120:e2312752120. [PMID: 38091292 PMCID: PMC10742375 DOI: 10.1073/pnas.2312752120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/14/2023] [Indexed: 12/18/2023] Open
Abstract
Somatostatin-expressing interneurons (SOMIs) in the mouse dentate gyrus (DG) receive feedforward excitation from granule cell (GC) mossy fiber (MF) synapses and provide feedback lateral inhibition onto GC dendrites to support environment representation in the DG network. Although this microcircuitry has been implicated in memory formation, little is known about activity-dependent plastic changes at MF-SOMI synapses and their influence on behavior. Here, we report that the metabotropic glutamate receptor 1α (mGluR1α) is required for the induction of associative long-term potentiation (LTP) at MF-SOMI synapses. Pharmacological block of mGluR1α, but not mGluR5, prevented synaptic weight changes. LTP at MF-SOMI synapses was postsynaptically induced, required increased intracellular Ca2+, involved G-protein-mediated and Ca2+-dependent (extracellular signal-regulated kinase) ERK1/2 pathways, and the activation of NMDA receptors. Specific knockdown of mGluR1α in DG-SOMIs by small hairpin RNA expression prevented MF-SOMI LTP, reduced SOMI recruitment, and impaired object location memory. Thus, postsynaptic mGluR1α-mediated MF-plasticity at SOMI input synapses critically supports DG-dependent mnemonic functions.
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Affiliation(s)
- Gayane Grigoryan
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Harumi Harada
- Molecular Physiology, Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - H. Sophie Knobloch-Bollmann
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Antje Kilias
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Dorthe Kaufhold
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Akos Kulik
- Molecular Physiology, Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Mark D. Eyre
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Marlene Bartos
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
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6
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Hanganu-Opatz IL, Klausberger T, Sigurdsson T, Nieder A, Jacob SN, Bartos M, Sauer JF, Durstewitz D, Leibold C, Diester I. Resolving the prefrontal mechanisms of adaptive cognitive behaviors: A cross-species perspective. Neuron 2023; 111:1020-1036. [PMID: 37023708 DOI: 10.1016/j.neuron.2023.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Received: 11/04/2022] [Revised: 02/15/2023] [Accepted: 03/10/2023] [Indexed: 04/08/2023]
Abstract
The prefrontal cortex (PFC) enables a staggering variety of complex behaviors, such as planning actions, solving problems, and adapting to new situations according to external information and internal states. These higher-order abilities, collectively defined as adaptive cognitive behavior, require cellular ensembles that coordinate the tradeoff between the stability and flexibility of neural representations. While the mechanisms underlying the function of cellular ensembles are still unclear, recent experimental and theoretical studies suggest that temporal coordination dynamically binds prefrontal neurons into functional ensembles. A so far largely separate stream of research has investigated the prefrontal efferent and afferent connectivity. These two research streams have recently converged on the hypothesis that prefrontal connectivity patterns influence ensemble formation and the function of neurons within ensembles. Here, we propose a unitary concept that, leveraging a cross-species definition of prefrontal regions, explains how prefrontal ensembles adaptively regulate and efficiently coordinate multiple processes in distinct cognitive behaviors.
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Affiliation(s)
- Ileana L Hanganu-Opatz
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, Hamburg Center of Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Thomas Klausberger
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, Vienna, Austria
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Goethe University, Frankfurt, Germany
| | - Andreas Nieder
- Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany
| | - Simon N Jacob
- Translational Neurotechnology Laboratory, Department of Neurosurgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Marlene Bartos
- Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg im Breisgau, Germany
| | - Jonas-Frederic Sauer
- Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg im Breisgau, Germany
| | - Daniel Durstewitz
- Department of Theoretical Neuroscience, Central Institute of Mental Health & Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Christian Leibold
- Faculty of Biology, Bernstein Center Freiburg, BrainLinks-BrainTools, University of Freiburg, Freiburg im Breisgau, Germany
| | - Ilka Diester
- Optophysiology - Optogenetics and Neurophysiology, IMBIT // BrainLinks-BrainTools, University of Freiburg, Freiburg im Breisgau, Germany.
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7
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Cholvin T, Bartos M. Hemisphere-specific spatial representation by hippocampal granule cells. Nat Commun 2022; 13:6227. [PMID: 36266288 PMCID: PMC9585038 DOI: 10.1038/s41467-022-34039-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 10/11/2022] [Indexed: 12/24/2022] Open
Abstract
The dentate gyrus (DG) output plays a key role in the emergence of spatial and contextual map representation within the hippocampus during learning. Differences in neuronal network activity have been observed between left and right CA1-3 areas, implying lateralization in spatial coding properties. Whether bilateral differences of DG granule cell (GC) assemblies encoding spatial and contextual information exist remains largely unexplored. Here, we employed two-photon calcium imaging of the left or the right DG to record the activity of GC populations over five consecutive days in head-fixed mice navigating through familiar and novel virtual environments. Imaging revealed similar mean GC activity on both sides. However, spatial tuning, context-selectivity and run-to-run place field reliability was markedly higher for DG place cells in the left than the right hemisphere. Moreover, the proportion of GCs reconfiguring their place fields between contexts was greater in the left DG. Thus, our data suggest that contextual information is differentially processed by GC populations depending on the hemisphere, with higher context discrimination in the left but a bias towards generalization in the right DG.
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Affiliation(s)
- Thibault Cholvin
- grid.5963.9Institute for Physiology I, University of Freiburg, Medical Faculty, 79104 Freiburg, Germany
| | - Marlene Bartos
- grid.5963.9Institute for Physiology I, University of Freiburg, Medical Faculty, 79104 Freiburg, Germany
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8
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Sauer JF, Bartos M. Disrupted-in-schizophrenia-1 is required for normal pyramidal cell-interneuron communication and assembly dynamics in the prefrontal cortex. eLife 2022; 11:79471. [PMID: 36239988 PMCID: PMC9566853 DOI: 10.7554/elife.79471] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
We interrogated prefrontal circuit function in mice lacking Disrupted-in-schizophrenia-1 (Disc1-mutant mice), a risk factor for psychiatric disorders. Single-unit recordings in awake mice revealed reduced average firing rates of fast-spiking interneurons (INTs), including optogenetically identified parvalbumin-positive cells, and a lower proportion of INTs phase-coupled to ongoing gamma oscillations. Moreover, we observed decreased spike transmission efficacy at local pyramidal cell (PYR)-INT connections in vivo, suggesting a reduced excitatory effect of local glutamatergic inputs as a potential mechanism of lower INT rates. On the network level, impaired INT function resulted in altered activation of PYR assemblies: While assembly activations defined as coactivations within 25 ms were observed equally often, the expression strength of individual assembly patterns was significantly higher in Disc1-mutant mice. Our data, thus, reveal a role of Disc1 in shaping the properties of prefrontal assembly patterns by setting INT responsiveness to glutamatergic drive.
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Affiliation(s)
- Jonas-Frederic Sauer
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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9
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Voss L, Bartos M, Elgueta C, Sauer JF. Interneuron function and cognitive behavior are preserved upon postnatal removal of Lhx6. Sci Rep 2022; 12:4923. [PMID: 35318414 PMCID: PMC8941127 DOI: 10.1038/s41598-022-09003-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 04/15/2021] [Accepted: 03/09/2022] [Indexed: 11/22/2022] Open
Abstract
LIM homeobox domain transcription factor 6 (Lhx6) is crucial for the prenatal specification and differentiation of hippocampal GABAergic interneuron precursors. Interestingly, Lhx6 remains to be expressed in parvalbumin-positive hippocampal interneurons (PVIs) long after specification and differentiation have been completed, the functional implications of which remain elusive. We addressed the role of adult-expressed Lhx6 in the hippocampus by knocking down Lhx6 in adult mice (> 8 weeks old) using viral or transgenic expression of Cre-recombinase in Lhx6loxP/loxP mice. Late removal of Lhx6 did not affect the number of PVIs and had no impact on the morphological and physiological properties of PVIs. Furthermore, mice lacking Lhx6 in PVIs displayed normal cognitive behavior. Loss of Lhx6 only partially reduced the expression of Sox6 and Arx, downstream transcription factors that depend on Lhx6 during embryonic development of PVIs. Our data thus suggest that while Lhx6 is vitally important to drive interneuron transcriptional networks during early development, it becomes uncoupled from downstream effectors during postnatal life.
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Affiliation(s)
- Lars Voss
- Institute of Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute of Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Institute of Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Jonas-Frederic Sauer
- Institute of Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany.
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10
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Strüber M, Sauer JF, Bartos M. Parvalbumin expressing interneurons control spike-phase coupling of hippocampal cells to theta oscillations. Sci Rep 2022; 12:1362. [PMID: 35079030 PMCID: PMC8789780 DOI: 10.1038/s41598-022-05004-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 12/30/2021] [Indexed: 12/13/2022] Open
Abstract
Encoding of information by hippocampal neurons is defined by the number and the timing of action potentials generated relative to ongoing network oscillations in the theta (5–14 Hz), gamma (30–80 Hz) and ripple frequency range (150–200 Hz). The exact mechanisms underlying the temporal coupling of action potentials of hippocampal cells to the phase of rhythmic network activity are not fully understood. One critical determinant of action potential timing is synaptic inhibition provided by a complex network of Gamma-amino-hydroxy-butyric acid releasing (GABAergic) interneurons. Among the various GABAergic cell types, particularly Parvalbumin-expressing cells are powerful regulators of neuronal activity. Here we silenced Parvalbumin-expressing interneurons in hippocampal areas CA1 and the dentate gyrus in freely moving mice using the optogenetic silencing tool eNpHR to determine their influence on spike timing in principal cells. During optogenetic inhibition of Parvalbumin-expressing cells, local field potential recordings revealed no change in power or frequency of CA1 or dentate gyrus network oscillations. However, CA1 pyramidal neurons exhibited significantly reduced spike-phase coupling to CA1 theta, but not gamma or ripple oscillations. These data suggest that hippocampal Parvalbumin-expressing interneurons are particularly important for an intact theta-based temporal coding scheme of hippocampal principal cell populations.
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11
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Ziegler-Waldkirch S, Friesen M, Loreth D, Sauer JF, Kemna S, Hilse A, Erny D, Helm C, d´Errico P, Prinz M, Bartos M, Meyer-Luehmann M. Seed-induced Aβ deposition alters neuronal function and impairs olfaction in a mouse model of Alzheimer's disease. Mol Psychiatry 2022; 27:4274-4284. [PMID: 35869271 PMCID: PMC9718674 DOI: 10.1038/s41380-022-01686-5] [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] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) which ultimately forms plaques. These Aβ deposits can be induced in APP transgenic mouse models by prion-like seeding. It has been widely accepted that anosmia and hyposmia occur during the early stages of AD, even before cognitive deficits are present. In order to determine the impact of seed-induced Aβ deposits on olfaction, we performed intracerebral injections of seed-competent brain homogenate into the olfactory bulb of young pre-depositing APP transgenic mice. Remarkably, we observed a dramatic olfactory impairment in those mice. Furthermore, the number of newborn neurons as well as the activity of cells in the mitral cell layer was decreased. Notably, exposure to an enriched environment reduced Aβ seeding, vivified neurogenesis and most importantly reversed olfactory deficits. Based on our findings, we conclude that altered neuronal function as a result of induced Aβ pathology might contribute to olfactory dysfunction in AD.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marina Friesen
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Desirée Loreth
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.13648.380000 0001 2180 3484Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jonas-Frederic Sauer
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany
| | - Solveig Kemna
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Alexandra Hilse
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Daniel Erny
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Christina Helm
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Paolo d´Errico
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marco Prinz
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Marlene Bartos
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center - University of Freiburg, 79106, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, 79110, Freiburg, Germany. .,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110, Freiburg, Germany.
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12
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Mossad O, Nent E, Woltemate S, Folschweiller S, Buescher JM, Schnepf D, Erny D, Staeheli P, Bartos M, Szalay A, Stecher B, Vital M, Sauer JF, Lämmermann T, Prinz M, Blank T. Microbiota-dependent increase in δ-valerobetaine alters neuronal function and is responsible for age-related cognitive decline. Nat Aging 2021; 1:1127-1136. [PMID: 37117525 DOI: 10.1038/s43587-021-00141-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 10/25/2021] [Indexed: 04/30/2023]
Abstract
Understanding the physiological origins of age-related cognitive decline is of critical importance given the rising age of the world's population1. Previous work in animal models has established a strong link between cognitive performance and the microbiota2-5, and it is known that the microbiome undergoes profound remodeling in older adults6. Despite growing evidence for the association between age-related cognitive decline and changes in the gut microbiome, the mechanisms underlying such interactions between the brain and the gut are poorly understood. Here, using fecal microbiota transplantation (FMT), we demonstrate that age-related remodeling of the gut microbiota leads to decline in cognitive function in mice and that this impairment can be rescued by transplantation of microbiota from young animals. Moreover, using a metabolomic approach, we found elevated concentrations of δ-valerobetaine, a gut microbiota-derived metabolite, in the blood and brain of aged mice and older adults. We then demonstrated that δ-valerobetaine is deleterious to learning and memory processes in mice. At the neuronal level, we showed that δ-valerobetaine modulates inhibitory synaptic transmission and neuronal network activity. Finally, we identified specific bacterial taxa that significantly correlate with δ-valerobetaine levels in the brain. Based on our findings, we propose that δ-valerobetaine contributes to microbiota-driven brain aging and that the associated mechanisms represent a promising target for countering age-related cognitive decline.
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Affiliation(s)
- Omar Mossad
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Elisa Nent
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Sabrina Woltemate
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Shani Folschweiller
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Institute of Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Joerg M Buescher
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Daniel Schnepf
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Daniel Erny
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Peter Staeheli
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute of Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Bärbel Stecher
- Max-von-Pettenkofer Institute, LMU Munich, Munich, Germany
- German Center for Infection Research (DZIF), partner site LMU Munich, Munich, Germany
| | - Marius Vital
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Jonas F Sauer
- Institute of Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tim Lämmermann
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
- Center for NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Blank
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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13
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Cholvin T, Hainmueller T, Bartos M. The hippocampus converts dynamic entorhinal inputs into stable spatial maps. Neuron 2021; 109:3135-3148.e7. [PMID: 34619088 PMCID: PMC8516433 DOI: 10.1016/j.neuron.2021.09.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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: 01/26/2021] [Revised: 05/31/2021] [Accepted: 09/09/2021] [Indexed: 11/29/2022]
Abstract
The medial entorhinal cortex (MEC)-hippocampal network plays a key role in the processing, storage, and recall of spatial information. However, how the spatial code provided by MEC inputs relates to spatial representations generated by principal cell assemblies within hippocampal subfields remains enigmatic. To investigate this coding relationship, we employed two-photon calcium imaging in mice navigating through dissimilar virtual environments. Imaging large MEC bouton populations revealed spatially tuned activity patterns. MEC inputs drastically changed their preferred spatial field locations between environments, whereas hippocampal cells showed lower levels of place field reconfiguration. Decoding analysis indicated that higher place field reliability and larger context-dependent activity-rate differences allow low numbers of principal cells, particularly in the DG and CA1, to provide information about location and context more accurately and rapidly than MEC inputs. Thus, conversion of dynamic MEC inputs into stable spatial hippocampal maps may enable fast encoding and efficient recall of spatio-contextual information. MEC inputs to the DG, CA3, and CA1 show different spatial coding properties MEC inputs remap even more strongly than hippocampal principal cells Hippocampal principal cell activity is more reliable and stable than their MEC inputs Hippocampal principal cells allow improved spatial and contextual readout
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Affiliation(s)
- Thibault Cholvin
- Institute for Physiology I, University of Freiburg, Medical Faculty, Freiburg 79104, Germany
| | - Thomas Hainmueller
- NYU Neuroscience Institute, 435 East 30th Street, New York, NY 10016, USA
| | - Marlene Bartos
- Institute for Physiology I, University of Freiburg, Medical Faculty, Freiburg 79104, Germany.
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14
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Adamkov J, Poczos P, Kanta M, Habalova J, Bartos M, Travnicek P, Mejzlik J, Cesak T. The effect of free glycerol intake on cerebral glycerol concentration. BRATISL MED J 2021; 122:24-27. [PMID: 33393316 DOI: 10.4149/bll_2021_032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Cerebral microdialysis (CMD) is a method used to measure the concentration of metabolites and glycerol in the interstitium of the brain. The aim of this study was to investigate the effect of parenterally applied medication and nutrition containing external free glycerol (EFG) on cerebral values of glycerol in patients monitored and treated for non-traumatic subarachnoid hemorrhage (SAH). METHODS In 13 patients, the values of CG concentrations were measured using CMD. The amounts of parenterally applied EFG (in hourly intervals) were calculated from patient records. All data were gathered retrospectively. To analyze the association between the parameters of interest and their relationship, Spearman´s correlation and p-values were calculated. RESULTS There was no evident relationship between the CG and EFG concentrations when the dataset was analyzed as a whole (r = -0.146). However, when the analysis was applied to single patients, a varying degree of correlations was discovered in 7 patients (r = 0.431-0.867). CONCLUSION The possible effect of externally administered glycerol contained in pharmaceuticals and nutrition on its brain concentrations must be considered when interpreting data of CMD (Tab. 2, Fig. 4,Ref. 16) Keywords: glycerol, microdialysis, brain, subarachnoid hemorrhage.
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15
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Paschen E, Elgueta C, Heining K, Vieira DM, Kleis P, Orcinha C, Häussler U, Bartos M, Egert U, Janz P, Haas CA. Hippocampal low-frequency stimulation prevents seizure generation in a mouse model of mesial temporal lobe epilepsy. eLife 2020; 9:54518. [PMID: 33349333 PMCID: PMC7800381 DOI: 10.7554/elife.54518] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 12/13/2020] [Indexed: 12/18/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common form of focal, pharmacoresistant epilepsy in adults and is often associated with hippocampal sclerosis. Here, we established the efficacy of optogenetic and electrical low-frequency stimulation (LFS) in interfering with seizure generation in a mouse model of MTLE. Specifically, we applied LFS in the sclerotic hippocampus to study the effects on spontaneous subclinical and evoked generalized seizures. We found that stimulation at 1 Hz for 1 hr resulted in an almost complete suppression of spontaneous seizures in both hippocampi. This seizure-suppressive action during daily stimulation remained stable over several weeks. Furthermore, LFS for 30 min before a pro-convulsive stimulus successfully prevented seizure generalization. Finally, acute slice experiments revealed a reduced efficacy of perforant path transmission onto granule cells upon LFS. Taken together, our results suggest that hippocampal LFS constitutes a promising approach for seizure control in MTLE.
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Affiliation(s)
- Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Systemic and Cellular Neurophysiology, Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Katharina Heining
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Diego M Vieira
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Piret Kleis
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Catarina Orcinha
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Systemic and Cellular Neurophysiology, Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ulrich Egert
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Philipp Janz
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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16
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Zinkiewicz M, Slobodeniuk AO, Kazimierczuk T, Kapuściński P, Oreszczuk K, Grzeszczyk M, Bartos M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Neutral and charged dark excitons in monolayer WS 2. Nanoscale 2020; 12:18153-18159. [PMID: 32853305 DOI: 10.1039/d0nr04243a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.
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Affiliation(s)
- M Zinkiewicz
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - A O Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Praha 2 CZ-121 16, Czech Republic
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - K Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland. and Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
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17
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Robert C, Han B, Kapuscinski P, Delhomme A, Faugeras C, Amand T, Molas MR, Bartos M, Watanabe K, Taniguchi T, Urbaszek B, Potemski M, Marie X. Measurement of the spin-forbidden dark excitons in MoS 2 and MoSe 2 monolayers. Nat Commun 2020; 11:4037. [PMID: 32788704 PMCID: PMC7423942 DOI: 10.1038/s41467-020-17608-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [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] [Received: 02/10/2020] [Accepted: 07/08/2020] [Indexed: 11/13/2022] Open
Abstract
Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30 T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14 meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field.
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Affiliation(s)
- C Robert
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
| | - B Han
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
| | - P Kapuscinski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - A Delhomme
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France.
| | - T Amand
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - B Urbaszek
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
| | - X Marie
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
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18
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Booker SA, Harada H, Elgueta C, Bank J, Bartos M, Kulik A, Vida I. Presynaptic GABA B receptors functionally uncouple somatostatin interneurons from the active hippocampal network. eLife 2020; 9:51156. [PMID: 32073397 PMCID: PMC7060044 DOI: 10.7554/elife.51156] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [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: 08/16/2019] [Accepted: 02/18/2020] [Indexed: 01/04/2023] Open
Abstract
Information processing in cortical neuronal networks relies on properly balanced excitatory and inhibitory neurotransmission. A ubiquitous motif for maintaining this balance is the somatostatin interneuron (SOM-IN) feedback microcircuit. Here, we investigated the modulation of this microcircuit by presynaptic GABAB receptors (GABABRs) in the rodent hippocampus. Whole-cell recordings from SOM-INs revealed that both excitatory and inhibitory synaptic inputs are strongly inhibited by GABABRs, while optogenetic activation of the interneurons shows that their inhibitory output is also strongly suppressed. Electron microscopic analysis of immunogold-labelled freeze-fracture replicas confirms that GABABRs are highly expressed presynaptically at both input and output synapses of SOM-INs. Activation of GABABRs selectively suppresses the recruitment of SOM-INs during gamma oscillations induced in vitro. Thus, axonal GABABRs are positioned to efficiently control the input and output synapses of SOM-INs and can functionally uncouple them from local network with implications for rhythmogenesis and the balance of entorhinal versus intrahippocampal afferents.
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Affiliation(s)
- Sam A Booker
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Harumi Harada
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Bank
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Akos Kulik
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
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19
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Elgueta C, Bartos M. Dendritic inhibition differentially regulates excitability of dentate gyrus parvalbumin-expressing interneurons and granule cells. Nat Commun 2019; 10:5561. [PMID: 31804491 PMCID: PMC6895125 DOI: 10.1038/s41467-019-13533-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [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] [Received: 04/08/2019] [Accepted: 11/11/2019] [Indexed: 11/25/2022] Open
Abstract
Fast-spiking parvalbumin-expressing interneurons (PVIs) and granule cells (GCs) of the dentate gyrus receive layer-specific dendritic inhibition. Its impact on PVI and GC excitability is, however, unknown. By applying whole-cell recordings, GABA uncaging and single-cell-modeling, we show that proximal dendritic inhibition in PVIs is less efficient in lowering perforant path-mediated subthreshold depolarization than distal inhibition but both are highly efficient in silencing PVIs. These inhibitory effects can be explained by proximal shunting and distal strong hyperpolarizing inhibition. In contrast, GC proximal but not distal inhibition is the primary regulator of their excitability and recruitment. In GCs inhibition is hyperpolarizing along the entire somato-dendritic axis with similar strength. Thus, dendritic inhibition differentially controls input-output transformations in PVIs and GCs. Dendritic inhibition in PVIs is suited to balance PVI discharges in dependence on global network activity thereby providing strong and tuned perisomatic inhibition that contributes to the sparse representation of information in GC assemblies. Fast-spiking parvalbumin-expressing interneurons (PVIs) and granule cells of the dentate gyrus receive layer-specific dendritic inhibition. The authors show that distal and proximal dendritic inhibition differentially control input-output transformations in PVIs and granule cells.
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Affiliation(s)
- Claudio Elgueta
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Medical Faculty of the University of Freiburg, 79104, Freiburg, Germany.
| | - Marlene Bartos
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Medical Faculty of the University of Freiburg, 79104, Freiburg, Germany.
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20
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Holz A, Mülsch F, Schwarz MK, Hollmann M, Döbrössy MD, Coenen VA, Bartos M, Normann C, Biber K, van Calker D, Serchov T. Enhanced mGlu5 Signaling in Excitatory Neurons Promotes Rapid Antidepressant Effects via AMPA Receptor Activation. Neuron 2019; 104:338-352.e7. [DOI: 10.1016/j.neuron.2019.07.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/14/2019] [Accepted: 07/12/2019] [Indexed: 12/14/2022]
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21
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Molas MR, Slobodeniuk AO, Nogajewski K, Bartos M, Bala Ł, Babiński A, Watanabe K, Taniguchi T, Faugeras C, Potemski M. Energy Spectrum of Two-Dimensional Excitons in a Nonuniform Dielectric Medium. Phys Rev Lett 2019; 123:136801. [PMID: 31697524 DOI: 10.1103/physrevlett.123.136801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate that, in monolayers (MLs) of semiconducting transition metal dichalcogenides, the s-type Rydberg series of excitonic states follows a simple energy ladder: ε_{n}=-Ry^{*}/(n+δ)^{2}, n=1,2,…, in which Ry^{*} is very close to the Rydberg energy scaled by the dielectric constant of the medium surrounding the ML and by the reduced effective electron-hole mass, whereas the ML polarizability is accounted for only by δ. This is justified by the analysis of experimental data on excitonic resonances, as extracted from magneto-optical measurements of a high-quality WSe_{2} ML encapsulated in hexagonal boron nitride (hBN), and well reproduced with an analytically solvable Schrödinger equation when approximating the electron-hole potential in the form of a modified Kratzer potential. Applying our convention to other MoSe_{2}, WS_{2}, MoS_{2} MLs encapsulated in hBN, we estimate an apparent magnitude of δ for each of the studied structures. Intriguingly, δ is found to be close to zero for WSe_{2} as well as for MoS_{2} monolayers, what implies that the energy ladder of excitonic states in these two-dimensional structures resembles that of Rydberg states of a three-dimensional hydrogen atom.
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Affiliation(s)
- M R Molas
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A O Slobodeniuk
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 61200 Brno, Czech Republic
| | - Ł Bala
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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22
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Molas MR, Slobodeniuk AO, Kazimierczuk T, Nogajewski K, Bartos M, Kapuściński P, Oreszczuk K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Basko DM, Potemski M. Probing and Manipulating Valley Coherence of Dark Excitons in Monolayer WSe_{2}. Phys Rev Lett 2019; 123:096803. [PMID: 31524465 DOI: 10.1103/physrevlett.123.096803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 06/10/2023]
Abstract
Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong spin-orbit interaction and the resulting ordering of the spin-split subbands in the valence and conduction bands makes the lowest-lying excitons in WX_{2} (X being S or Se) spin forbidden and optically dark. With polarization-resolved photoluminescence experiments performed on a WSe_{2} monolayer encapsulated in a hexagonal boron nitride, we show how the intrinsic exchange interaction in combination with the applied in-plane and/or out-of-plane magnetic fields enables one to probe and manipulate the valley degree of freedom of the dark excitons.
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Affiliation(s)
- M R Molas
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A O Slobodeniuk
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, 27 Wybrzeże Wyspiańskiego, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - D M Basko
- Laboratoire de Physique et Modélisation des Milieux Condensés, Université Grenoble Alpes and CNRS, 25 avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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23
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Eyre MD, Bartos M. Somatostatin-Expressing Interneurons Form Axonal Projections to the Contralateral Hippocampus. Front Neural Circuits 2019; 13:56. [PMID: 31507383 PMCID: PMC6716454 DOI: 10.3389/fncir.2019.00056] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 05/29/2019] [Accepted: 08/08/2019] [Indexed: 12/31/2022] Open
Abstract
Conscious memories are critically dependent upon bilateral hippocampal formation, and interhemispheric commissural projections made by mossy cells and CA3 pyramidal cells. GABAergic interneurons also make long-range axonal projections, but little is known regarding their commissural, inter-hippocampal connections. We used retrograde and adeno-associated viral tracing, immunofluorescence and electron microscopy, and in vitro optogenetics to assess contralateral projections of neurochemically defined interneuron classes. We found that contralateral-projecting interneurons were 24-fold less common compared to hilar mossy cells, and mostly consisted of somatostatin- and parvalbumin-expressing types. Somatostatin-expressing cells made denser contralateral axonal projections than parvalbumin-expressing cells, although this was typically 10-fold less than the ipsilateral projection density. Somatostatin-expressing cells displayed a topographic-like innervation according to the location of their somata, whereas parvalbumin-expressing cells mostly innervated CA1. In the dentate gyrus molecular layer, commissural interneuron post-synaptic targets were predominantly putative granule cell apical dendrites. In the hilus, varicosities in close vicinity to various interneuron subtypes, as well as mossy cells, were observed, but most contralateral axon varicosities had no adjacent immunolabeled structure. Due to the relative sparsity of the connection and the likely distal dendritic location of their synapses, commissural projections made by interneurons were found to be weak. We postulate that these projections may become functionally active upon intense network activity during tasks requiring increased memory processing.
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Affiliation(s)
- Mark D Eyre
- Medical Faculty, Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Medical Faculty, Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany
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24
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Menon V, Thomas R, Elgueta C, Horl M, Osborn T, Hallett PJ, Bartos M, Isacson O, Pruszak J. Comprehensive Cell Surface Antigen Analysis Identifies Transferrin Receptor Protein-1 (CD71) as a Negative Selection Marker for Human Neuronal Cells. Stem Cells 2019; 37:1293-1306. [PMID: 31381839 PMCID: PMC6851846 DOI: 10.1002/stem.3057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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] [Received: 05/21/2018] [Revised: 04/23/2019] [Accepted: 05/14/2019] [Indexed: 12/20/2022]
Abstract
Cell state‐, developmental stage‐, and lineage‐specific combinatorial expression of cluster of differentiation (CD) molecules enables the identification of cellular subsets via multicolor flow cytometry. We describe an exhaustive characterization of neural cell types by surface antigens, exploiting human pluripotent stem cell‐derived neural cell systems. Using multiwell screening approaches followed by detailed validation of expression patterns and dynamics, we exemplify a strategy for resolving cellular heterogeneity in stem cell paradigms. In addition to providing a catalog of surface antigens expressed in the neural lineage, we identified the transferrin receptor‐1 (CD71) to be differentially expressed in neural stem cells and differentiated neurons. In this context, we describe a role for N‐Myc proto‐oncogene (MYCN) in maintaining CD71 expression in proliferating neural cells. We report that in vitro human stem cell‐derived neurons lack CD71 surface expression and that the observed differential expression can be used to identify and enrich CD71− neuronal derivatives from heterogeneous cultures. stem cells2019;37:1293–1306
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Affiliation(s)
- Vishal Menon
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM) and Faculty of Biology, University of Freiburg, Freiburg, Germany.,Freiburg iPS Core (FiPS), Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ria Thomas
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM) and Faculty of Biology, University of Freiburg, Freiburg, Germany.,Neuroregeneration Laboratories, McLean Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Claudio Elgueta
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marcus Horl
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Teresia Osborn
- Neuroregeneration Laboratories, McLean Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Penny J Hallett
- Neuroregeneration Laboratories, McLean Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marlene Bartos
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ole Isacson
- Neuroregeneration Laboratories, McLean Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jan Pruszak
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Freiburg iPS Core (FiPS), Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Center for Biological Signaling Studies (BIOSS), University of Freiburg, Freiburg, Germany
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25
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Cesak T, Adamkov J, Habalova J, Poczos P, Kanta M, Bartos M, Hosszu T. The relationship between intracranial pressure and lactate/pyruvate ratio in patients with subarachnoid haemorrhage. ACTA ACUST UNITED AC 2018. [PMID: 29536741 DOI: 10.4149/bll_2018_027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AIM The aim of this study was to analyse the relationship between intracranial pressure (intracranial pressure monitoring) and lactate pyruvate ratio (cerebral microdialysis) in patients with ruptured intracranial aneurysms. METHODS In a group of fifteen patients, intracranial pressure and lactate/pyruvate ratios were measured and logged in hourly intervals. The relationship between these two variables was subsequently analysed in two ways. 1) Intracranial hypertension (ICP > 20 mmHg) in the presence of energy deprivation (L/P ratio > 30) was noted. 2) The dynamics of L/P ratio changes in relation to immediate ICP and CPP values was analysed. RESULTS Out of a total of 1873 monitored hours we were able to record lactate/pyruvate ratios higher than 30 in 832 hours (44 %). Of those 832 hours during which lactate/pyruvate ratios were higher than 30, ICP was higher than 20 in 193 hours (23 %). Out of 219 hours of monitoring, in which ICP was higher than 20, a simultaneously increased L/P ratio higher than 30 was recorded in 193 hours (88 %). L/P ratio values above 30 were associated with decreased CPP values (p = 0.04), but not with increased ICP values (p = 0.79). CONCLUSION Intracranial hypertension coincides with energetic imbalance in approximately one quarter of cases. This points to the shortcomings of the most common form of neuromonitoring in SAH patients - ICP monitoring. This method may not be reliable enough in detecting hypoxic damage, which is the major cause of morbidity and mortality in SAH patients (Fig. 5, Ref. 11).
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26
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Vaclavkova D, Wyzula J, Nogajewski K, Bartos M, Slobodeniuk AO, Faugeras C, Potemski M, Molas MR. Singlet and triplet trions in WS 2 monolayer encapsulated in hexagonal boron nitride. Nanotechnology 2018; 29:325705. [PMID: 29781447 DOI: 10.1088/1361-6528/aac65c] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Embedding a WS2 monolayer in flakes of hexagonal boron nitride allowed us to resolve and study the photoluminescence response due to both singlet and triplet states of negatively charged excitons (trions) in this atomically thin semiconductor. The energy separation between the singlet and triplet states has been found to be relatively small reflecting rather weak effects of the electron-electron exchange interaction for the trion triplet in a WS2 monolayer, which involves two electrons with the same spin but from different valleys. Polarization-resolved experiments demonstrate that the helicity of the excitation light is better preserved in the emission spectrum of the triplet trion than in that of the singlet trion. Finally, the singlet (intravalley) trions are found to be observable even at ambient conditions whereas the emission due to the triplet (intervalley) trions is only efficient at low temperatures.
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Affiliation(s)
- D Vaclavkova
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, F-38042 Grenoble, France. Department of Experimental Physics, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czechia
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27
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Abstract
The local field potential (LFP) emerges from ion movements across neural membranes. Since the voltage recorded by LFP electrodes reflects the summed electrical field of a large volume of brain tissue, extracting information about local activity is challenging. Studying neuronal microcircuits, however, requires a reliable distinction between truly local events and volume-conducted signals originating in distant brain areas. Current source density (CSD) analysis offers a solution for this problem by providing information about current sinks and sources in the vicinity of the electrodes. In brain areas with laminar cytoarchitecture such as the hippocampus, one-dimensional CSD can be obtained by estimating the second spatial derivative of the LFP. Here, we describe a method to record multilaminar LFPs using linear silicon probes implanted into the dorsal hippocampus. CSD traces are computed along individual shanks of the probe. This protocol thus describes a procedure to resolve spatially restricted neuronal network oscillations in the hippocampus of freely moving mice.
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28
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Hainmueller T, Bartos M. Parallel emergence of stable and dynamic memory engrams in the hippocampus. Nature 2018; 558:292-296. [PMID: 29875406 DOI: 10.1038/s41586-018-0191-2] [Citation(s) in RCA: 187] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/30/2018] [Indexed: 12/31/2022]
Abstract
During our daily life, we depend on memories of past experiences to plan future behaviour. These memories are represented by the activity of specific neuronal groups or 'engrams'1,2. Neuronal engrams are assembled during learning by synaptic modification, and engram reactivation represents the memorized experience 1 . Engrams of conscious memories are initially stored in the hippocampus for several days and then transferred to cortical areas 2 . In the dentate gyrus of the hippocampus, granule cells transform rich inputs from the entorhinal cortex into a sparse output, which is forwarded to the highly interconnected pyramidal cell network in hippocampal area CA3 3 . This process is thought to support pattern separation 4 (but see refs. 5,6). CA3 pyramidal neurons project to CA1, the hippocampal output region. Consistent with the idea of transient memory storage in the hippocampus, engrams in CA1 and CA2 do not stabilize over time7-10. Nevertheless, reactivation of engrams in the dentate gyrus can induce recall of artificial memories even after weeks 2 . Reconciliation of this apparent paradox will require recordings from dentate gyrus granule cells throughout learning, which has so far not been performed for more than a single day6,11,12. Here, we use chronic two-photon calcium imaging in head-fixed mice performing a multiple-day spatial memory task in a virtual environment to record neuronal activity in all major hippocampal subfields. Whereas pyramidal neurons in CA1-CA3 show precise and highly context-specific, but continuously changing, representations of the learned spatial sceneries in our behavioural paradigm, granule cells in the dentate gyrus have a spatial code that is stable over many days, with low place- or context-specificity. Our results suggest that synaptic weights along the hippocampal trisynaptic loop are constantly reassigned to support the formation of dynamic representations in downstream hippocampal areas based on a stable code provided by the dentate gyrus.
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Affiliation(s)
- Thomas Hainmueller
- Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany.
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29
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Ziegler-Waldkirch S, d'Errico P, Sauer JF, Erny D, Savanthrapadian S, Loreth D, Katzmarski N, Blank T, Bartos M, Prinz M, Meyer-Luehmann M. Seed-induced Aβ deposition is modulated by microglia under environmental enrichment in a mouse model of Alzheimer's disease. EMBO J 2017; 37:167-182. [PMID: 29229786 PMCID: PMC5770788 DOI: 10.15252/embj.201797021] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [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: 03/27/2017] [Revised: 10/13/2017] [Accepted: 11/08/2017] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by severe neuronal loss as well as the accumulation of amyloid‐β (Aβ), which ultimately leads to plaque formation. Although there is now a general agreement that the aggregation of Aβ can be initiated by prion‐like seeding, the impact and functional consequences of induced Aβ deposits (Aβ seeding) on neurons still remain open questions. Here, we find that Aβ seeding, representing early stages of plaque formation, leads to a dramatic decrease in proliferation and neurogenesis in two APP transgenic mouse models. We further demonstrate that neuronal cell death occurs primarily in the vicinity of induced Aβ deposits culminating in electrophysiological abnormalities. Notably, environmental enrichment and voluntary exercise not only revives adult neurogenesis and reverses memory deficits but, most importantly, prevents Aβ seeding by activated, phagocytic microglia cells. Our work expands the current knowledge regarding Aβ seeding and the consequences thereof and attributes microglia an important role in diminishing Aβ seeding by environmental enrichment.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- Department of Neurology, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Paolo d'Errico
- Department of Neurology, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jonas-Frederic Sauer
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany
| | - Daniel Erny
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Neuropathology, Medical Center - University of Freiburg, Freiburg, Germany.,Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Shakuntala Savanthrapadian
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany
| | - Desirée Loreth
- Department of Neurology, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Natalie Katzmarski
- Department of Neurology, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Thomas Blank
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Neuropathology, Medical Center - University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Neuropathology, Medical Center - University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center - University of Freiburg, Freiburg, Germany .,Faculty of Medicine, University of Freiburg, Freiburg, Germany
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30
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Janz P, Savanthrapadian S, Häussler U, Kilias A, Nestel S, Kretz O, Kirsch M, Bartos M, Egert U, Haas CA. Synaptic Remodeling of Entorhinal Input Contributes to an Aberrant Hippocampal Network in Temporal Lobe Epilepsy. Cereb Cortex 2017; 27:2348-2364. [PMID: 27073230 DOI: 10.1093/cercor/bhw093] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hippocampus is reciprocally connected with the entorhinal cortex. Although several studies emphasized a role for the entorhinal cortex in mesial temporal lobe epilepsy (MTLE), it remains uncertain whether its synaptic connections with the hippocampus are altered. To address this question, we traced hippocampo-entorhinal and entorhino-hippocampal projections, assessed their connectivity with the respective target cells and examined functional alterations in a mouse model for MTLE. We show that hippocampal afferents to the dorsal entorhinal cortex are lost in the epileptic hippocampus. Conversely, entorhino-dentate projections via the medial perforant path (MPP) are preserved, but appear substantially altered on the synaptic level. Confocal imaging and 3D-reconstruction revealed that new putative contacts are established between MPP fibers and dentate granule cells (DGCs). Immunohistochemical identification of pre- and postsynaptic elements indicated that these contacts are functionally mature synapses. On the ultrastructural level, pre- and postsynaptic compartments of MPP synapses were strongly enlarged. The length and complexity of postsynaptic densities were also increased pointing to long-term potentiation-related morphogenesis. Finally, whole-cell recordings of DGCs revealed an enhancement of evoked excitatory postsynaptic currents. In conclusion, the synaptic rearrangement of excitatory inputs to DGCs from the medial entorhinal cortex may contribute to the epileptogenic circuitry in MTLE.
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Affiliation(s)
- Philipp Janz
- Experimental Epilepsy Research, Department of Neurosurgery.,Faculty of Biology
| | | | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery
| | - Antje Kilias
- Faculty of Biology.,Laboratory for Biomicrotechnology, Department of Microsystems Engineering, Freiburg im Breisgau 79110, Germany.,Bernstein Center Freiburg, Freiburg im Breisgau 79104, Germany
| | - Sigrun Nestel
- Neuroanatomy, Department of Anatomy and Cell Biology
| | - Oliver Kretz
- Renal Division, Department of Medicine, University Medical Center Freiburg, Freiburg im Breisgau 79106, Germany
| | | | - Marlene Bartos
- Institute for Physiology I, Systemic and Cellular Neurophysiology.,Bernstein Center Freiburg, Freiburg im Breisgau 79104, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg im Breisgau 79110, Germany
| | - Ulrich Egert
- Laboratory for Biomicrotechnology, Department of Microsystems Engineering, Freiburg im Breisgau 79110, Germany.,Bernstein Center Freiburg, Freiburg im Breisgau 79104, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg im Breisgau 79110, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery.,Bernstein Center Freiburg, Freiburg im Breisgau 79104, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg im Breisgau 79110, Germany
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31
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Yuan M, Meyer T, Benkowitz C, Savanthrapadian S, Ansel-Bollepalli L, Foggetti A, Wulff P, Alcami P, Elgueta C, Bartos M. Somatostatin-positive interneurons in the dentate gyrus of mice provide local- and long-range septal synaptic inhibition. eLife 2017; 6. [PMID: 28368242 PMCID: PMC5395294 DOI: 10.7554/elife.21105] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [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: 08/31/2016] [Accepted: 04/01/2017] [Indexed: 01/16/2023] Open
Abstract
Somatostatin-expressing-interneurons (SOMIs) in the dentate gyrus (DG) control formation of granule cell (GC) assemblies during memory acquisition. Hilar-perforant-path-associated interneurons (HIPP cells) have been considered to be synonymous for DG-SOMIs. Deviating from this assumption, we show two functionally contrasting DG-SOMI-types. The classical feedback-inhibitory HIPPs distribute axon fibers in the molecular layer. They are engaged by converging GC-inputs and provide dendritic inhibition to the DG circuitry. In contrast, SOMIs with axon in the hilus, termed hilar interneurons (HILs), provide perisomatic inhibition onto GABAergic cells in the DG and project to the medial septum. Repetitive activation of glutamatergic inputs onto HIPP cells induces long-lasting-depression (LTD) of synaptic transmission but long-term-potentiation (LTP) of synaptic signals in HIL cells. Thus, LTD in HIPPs may assist flow of spatial information from the entorhinal cortex to the DG, whereas LTP in HILs may facilitate the temporal coordination of GCs with activity patterns governed by the medial septum. DOI:http://dx.doi.org/10.7554/eLife.21105.001
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Affiliation(s)
- Mei Yuan
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany.,Faculty for Biology, University of Freiburg, Freiburg, Germany
| | - Thomas Meyer
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
| | - Christoph Benkowitz
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
| | - Shakuntala Savanthrapadian
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
| | | | | | - Peer Wulff
- Institute for Physiology, University of Kiel, Kiel, Germany
| | - Pepe Alcami
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Systemic and Cellular Neurophysiology, Institute for Physiology I, University of Freiburg, Freiburg, Germany
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Biskamp J, Bartos M, Sauer JF. Organization of prefrontal network activity by respiration-related oscillations. Sci Rep 2017; 7:45508. [PMID: 28349959 PMCID: PMC5368652 DOI: 10.1038/srep45508] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [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] [Received: 10/27/2016] [Accepted: 03/01/2017] [Indexed: 02/08/2023] Open
Abstract
The medial prefrontal cortex (mPFC) integrates information from cortical and sub-cortical areas and contributes to the planning and initiation of behaviour. A potential mechanism for signal integration in the mPFC lies in the synchronization of neuronal discharges by theta (6–12 Hz) activity patterns. Here we show, using in vivo local field potential (LFP) and single-unit recordings from awake mice, that prominent oscillations in the sub-theta frequency band (1–5 Hz) emerge during awake immobility in the mPFC. These oscillation patterns are distinct from but phase-locked to hippocampal theta activity and occur synchronized with nasal respiration (hence termed prefrontal respiration rhythm [PRR]). PRR activity modulates the amplitude of prefrontal gamma rhythms with greater efficacy than theta oscillations. Furthermore, single-unit discharges of putative pyramidal cells and GABAergic interneurons are entrained by prefrontal PRR and nasal respiration. Our data thus suggest that PRR activity contributes to information processing in the prefrontal neuronal network.
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Affiliation(s)
- Jonatan Biskamp
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 7, 79104 Freiburg, Germany
| | - Marlene Bartos
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 7, 79104 Freiburg, Germany
| | - Jonas-Frederic Sauer
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 7, 79104 Freiburg, Germany
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Abstract
Rhythmic neuronal activity provides a frame for information coding by co-active cell assemblies. Abnormal brain rhythms are considered as potential pathophysiological mechanisms causing mental disease, but the underlying network defects are largely unknown. We find that mice expressing truncated Disrupted-in-Schizophrenia 1 (Disc1), which mirror a high-prevalence genotype for human psychiatric illness, show depression-related behavior. Theta and low-gamma synchrony in the prelimbic cortex (PrlC) is impaired in Disc1 mice and inversely correlated with the extent of behavioural despair. While weak theta activity is driven by the hippocampus, disturbance of low-gamma oscillations is caused by local defects of parvalbumin (PV)-expressing fast-spiking interneurons (FS-INs). The number of FS-INs is reduced, they receive fewer excitatory inputs, and form fewer release sites on targets. Computational analysis indicates that weak excitatory input and inhibitory output of FS-INs may lead to impaired gamma oscillations. Our data link network defects with a gene mutation underlying depression in humans. DOI:http://dx.doi.org/10.7554/eLife.04979.001 Our thoughts and emotions are produced and processed by complex networks of neurons inside our brains. Signals are sent from one neuron to another via chemical messengers, and pass through the neuron as an electrical signal. The electrical signals produced by a brain region often show steady rhythms, or oscillations. In the brains of many people diagnosed with certain mental disorders, such as schizophrenia and major depression, these oscillations are disrupted, but how these changes in rhythm are linked to defects in the networks of neurons behind the electrical activity is not well understood. Studies of a family in Scotland over several decades revealed that a gene called DISC1 was shortened in family members who had been diagnosed with mental illnesses. Recently, scientists have been able to create mice that have mutations that are equivalent to this DISC1 mutation. It is hoped that studying the behavior and neural activity of these mutant mice could lead to a better understanding of human mental disorders. Sauer et al. confirmed that the mutant mice showed depression-related behavior; in experiments that involved trying to escape from hopeless situations, the mutant mice gave up on their escape attempts much sooner than the normal mice. Recording the brain activity of these ‘depressed’ mice showed that the activity of a brain region called the prelimbic cortex was weak and disordered—very much like the brain activity seen in human depression. In particular, two types of brain activity, called theta and low-gamma oscillations, were not synchronized. To determine precisely what causes these abnormal oscillations, Sauer et al. took brain slices from depressed mice, and then stained them with dyes that showed the circuits in the prelimbic cortex more clearly. This revealed that depressed mice had developmental defects in a specific type of inhibitory neuron called fast-spiking interneurons—there were fewer of these cells, and the neurons that were there did not have the correct number of connections to other neurons. Further investigation showed that these neurons had difficulties receiving and releasing the chemical messengers that allow neurons to communicate, and Sauer et al. thought that this might cause the low-gamma oscillation problems. To confirm this theory, Sauer et al. created a computer model that simulated the defective interneurons. The simulations support the theory that the defects in the fast-spiking interneurons cause the abnormal low-gamma rhythms seen in depressed mice. In the future, a better understanding of the defects of inhibitory cells in DISC1 mutants and other mouse models of mental illness might open up new avenues for targeted drug design. As the prelimbic cortex combines inputs from various other brain areas, a further challenge will be to examine whether these inputs influence the activity of the prelimbic cortex and thus contribute to depression-related behavior. DOI:http://dx.doi.org/10.7554/eLife.04979.002
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Affiliation(s)
- Jonas-Frederic Sauer
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Michael Strüber
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Physiologisches Institut I, Systemic and Cellular Neurophysiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Hosp JA, Strüber M, Yanagawa Y, Obata K, Vida I, Jonas P, Bartos M. Morpho-physiological criteria divide dentate gyrus interneurons into classes. Hippocampus 2014; 24:189-203. [PMID: 24108530 PMCID: PMC4165310 DOI: 10.1002/hipo.22214] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 09/13/2013] [Accepted: 10/02/2013] [Indexed: 12/14/2022]
Abstract
GABAergic inhibitory interneurons control fundamental aspects of neuronal network function. Their functional roles are assumed to be defined by the identity of their input synapses, the architecture of their dendritic tree, the passive and active membrane properties and finally the nature of their postsynaptic targets. Indeed, interneurons display a high degree of morphological and physiological heterogeneity. However, whether their morphological and physiological characteristics are correlated and whether interneuron diversity can be described by a continuum of GABAergic cell types or by distinct classes has remained unclear. Here we perform a detailed morphological and physiological characterization of GABAergic cells in the dentate gyrus, the input region of the hippocampus. To achieve an unbiased and efficient sampling and classification we used knock-in mice expressing the enhanced green fluorescent protein (eGFP) in glutamate decarboxylase 67 (GAD67)-positive neurons and performed cluster analysis. We identified five interneuron classes, each of them characterized by a distinct set of anatomical and physiological parameters. Cross-correlation analysis further revealed a direct relation between morphological and physiological properties indicating that dentate gyrus interneurons fall into functionally distinct classes which may differentially control neuronal network activity.
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Affiliation(s)
- Jonas A Hosp
- Institute for Physiology I, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 779104, Freiburg, Germany
- Clinical Neurorehabilitation, Department of Neurology, University of Zurich8091, Zurich, Switzerland
| | - Michael Strüber
- Institute for Physiology I, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 779104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM) and Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg79104, Freiburg, Germany
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University3-39-22, Showa-Machi, Japan
| | - Kunihiko Obata
- Laboratory of Neurochemistry, National Institute for Physiological Sciences444-8585, Myodaiji, Okazaki, Japan
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité Berlin, Phillipstraße 1210115, Berlin, Germany
| | - Peter Jonas
- IST Austria (Institute of Science and Technology Austria), Am Campus 13400, Klosterneuburg, Austria
| | - Marlene Bartos
- Institute for Physiology I, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 779104, Freiburg, Germany
- *Correspondence to: Prof. Dr. M. Bartos, Institut für Physiologie I, Universität Freiburg, Hermann-Herder Strasse 7, D-79108 Freiburg, Germany. E-mail:
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Abstract
Most GABAergic interneurons in the cortex are born at embryonic stages in the ganglionic eminences and migrate tangentially to their final destination. They continue, however, to differentiate and functionally integrate in the circuitry until later postnatal stages of the rodent brain. Recent investigations show that interneurons undergo marked changes in their morphological, intrinsic and synaptic properties as they mature. Action potential shape and its propagation, the period of transmitter release and the time course of the postsynaptic GABA(A) receptor-mediated conductance become faster during the first three to four postnatal weeks, resulting in a developmental switch of interneurons from slow to fast signalling units. At the same time, the nature of GABAergic signalling is classically considered to shift from depolarizing to hyperpolarizing. However, recent studies oppose this view as interneuron synapses can be shunting, excitatory or hyperpolarizing in the mature cortex, demonstrating the coexistence of diverse developmental rules for the emerging effects of GABAergic synapses. Thus, mature interneuron signalling comes in many forms and is apparently optimized to the network in which the neurons are embedded.
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Affiliation(s)
- Jonas-Frederic Sauer
- Institute of Physiology 1, University of Freiburg, Hermann-Herder-Strasse 7, D-70104 Freiburg, Germany
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Janco L, Vida R, Bartos M, Villémová K, Izák M. [Gases in vitreoretinal surgery]. Cesk Slov Oftalmol 2012; 68:3-10. [PMID: 22679691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
AIM To evaluate the importance and benefits of using gases in vitreoretinal surgery. MATERIAL AND METHODS The gases represent a wide group of substances used in eye surgery for more than 100 years. The role of intraocular gases in vitreoretinal surgery is irreplaceable. Their use is still considered to be the "gold standard". An important step in eye surgery was the introduction of expanding gases--sulfur hexafluoride and perfluorocarbons into routine clinical practice. The most common indications for the use of intraocular gases are: retinal detachment, idiopathic macular hole, complications of vitreoretinal surgery and others. RESULTS AND CONCLUSIONS The introduction of intraocular gases into routine clinical practice, along with other modern surgical techniques resulted in significant improvement of postoperative outcomes in a wide range of eye diseases. Understanding the principles of intraocular gases use brings the benefits to the patient and physician as well. Due to their physical and chemical properties they pose far the best and most appropriate variant of intraocular tamponade. Gases also bring some disadvantages, such as difficulties in detailed fundus examination, visual acuity testing, ultrasonographic examination, difficulties in application of intravitreal drugs or reduced possibility of retina laser treatment. The gases significantly change optical system properties of the eye. The use of gases in vitreoretinal surgery has significantly increased success rate of retinal detachment surgery, complicated posterior segment cases, trauma, surgery of the macula and other diseases.
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Affiliation(s)
- L Janco
- ll. Ocná Klinika SZU, FNsP F.D. Roosevelta, Banská Bystrica.
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Abstract
Cortical neuronal network operations depend critically on the recruitment of GABAergic interneurons and the properties of their inhibitory output signals. Recent evidence indicates a marked difference in the signalling properties of two major types of perisomatic inhibitory interneurons, the parvalbumin- and the cholecystokinin-containing basket cells. Parvalbumin-expressing basket cells are rapidly recruited by excitatory synaptic inputs, generate high-frequency trains of action potentials, discharge single action potentials phase-locked to fast network oscillations and provide fast, stable and timed inhibitory output onto their target cells. In contrast, cholecystokinin-containing basket cells are recruited in a less reliable manner, discharge at moderate frequencies with single action potentials weakly coupled to the phases of fast network oscillations and generate an asynchronous, fluctuating and less timed inhibitory output. These signalling modes are based on cell type-dependent differences in the functional and plastic properties of excitatory input synapses, integrative qualities and in the kinetics and dynamics of inhibitory output synapses. Thus, the two perisomatic inhibitory interneuron types operate with different speed and precision and may therefore contribute differently to the operations of neuronal networks.
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Affiliation(s)
- Marlene Bartos
- Physiologisches Institut I, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Straße 7, 79104 Freiburg, Germany.
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Bartos M, Alle H, Vida I. Role of microcircuit structure and input integration in hippocampal interneuron recruitment and plasticity. Neuropharmacology 2010; 60:730-9. [PMID: 21195097 DOI: 10.1016/j.neuropharm.2010.12.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 12/10/2010] [Accepted: 12/15/2010] [Indexed: 11/25/2022]
Abstract
The proper operation of cortical neuronal networks depends on the temporally precise recruitment of GABAergic inhibitory interneurons. Inhibitory cells receive convergent excitatory inputs from afferent pathways, as well as local collaterals of principal cells, and provide feedforward or feedback inhibition within the circuitry. Accumulating evidence indicates that recruitment of GABAergic cells is highly diverse among interneuron types. Differences in the properties of input synapses, dendritic architecture and membrane properties, as well as the rich repertoire of plasticity mechanisms contribute to this diversity. Efficient and precise recruitment of interneurons is thought to depend on the coincident occurrence of rapid synaptic responses and their faithful propagation to the action potential initiation site. However, slow inputs can also play important roles by facilitating the activation of interneurons by rapid synaptic inputs and supporting associative synaptic plasticity. Here we review how the diversity in the synaptic and integrative properties as well as dendritic geometry of hippocampal inhibitory cells impact on their activation. We further discuss how the various modes of interneuron recruitment can support the versatile cell type- and input-specific computational functions which appear to be adapted to the structure and the function of the network they are embedded in. This article is part of a Special Issue entitled 'Synaptic Plasticity & Interneurons'.
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Affiliation(s)
- Marlene Bartos
- Institute of Physiology 1, University of Freiburg, Engesser Strasse 4, D-79108 Freiburg, Germany.
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Abstract
It has been shown that besides positron emission tomography, single photon emission computed tomography and magnetic resonance imaging; contrast echocardiography can be used for qualitative and quantitative myocardial perfusion assessment. In this review, the properties of ultrasound contrast agents, imaging techniques and acquisition methods are shortly described and the possibilities of perfusion echocardiography are summarized. The main focus is put on the description of three perfusion models: mathematical models, physical models assuming an ideal inflow and physical models including inflow measurement.
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Affiliation(s)
- R Kolář
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czech Republic.
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Hosek J, Závalová V, Smejkal K, Bartos M. Effect of diplacone on LPS-induced inflammatory gene expression in macrophages. Folia Biol (Praha) 2010; 56:124-130. [PMID: 20653997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Flavonoids are commonly studied for their anti-inflammatory effects; however, this is the first paper describing the possible antiphlogistic activity of a geranylated flavanone. This study focused on the ability of diplacone to modulate the gene expression of pro-inflammatory tumour necrosis factor alpha and monocyte chemoattractant protein 1, and of anti-inflammatory zinc finger protein 36. The action of diplacone was also compared with that of conventional drug indomethacin. Human monocyte-derived macrophages of the human monocytic leukaemia cell line were pretreated with diplacone or indomethacin. Subsequently, inflammatory reaction was induced by lipopolysaccharide, and changes of tumour necrosis factor alpha, monocyte chemoattractant protein 1 and zinc finger protein 36 gene expression at the transcriptional level were measured. In this model, diplacone significantly down-regulated the expression of tumour necrosis factor alpha and monocyte chemoattractant protein 1 and up-regulated the zinc finger protein 36 expression. This makes diplacone a promising molecule for treatment of the inflammatory stage of diseases. The effect of diplacone in decreasing lipopolysaccharide-induced inflammatory gene expression is in many ways similar to that of the conventional drug indomethacin.
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Affiliation(s)
- J Hosek
- Department of Natural Drugs, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
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Kaban I, Jóvári P, Wagner T, Frumar M, Stehlik S, Bartos M, Hoyer W, Beuneu B, Webb MA. Atomic structure of As(2)S(3)-Ag chalcogenide glasses. J Phys Condens Matter 2009; 21:395801. [PMID: 21832397 DOI: 10.1088/0953-8984/21/39/395801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
(As(0.4)S(0.6))(100-x)Ag(x) glasses (x = 0, 4, 8, 12 at.%) have been studied with high-energy x-ray diffraction, neutron diffraction and extended x-ray absorption spectroscopy at As and Ag K-edges. The experimental data were modelled simultaneously with the reverse Monte Carlo simulation method. Analysis of the partial pair correlation functions and coordination numbers extracted from the model atomic configurations revealed that silver preferentially bonds to sulfur in the As(2)S(3)-Ag ternary glasses, which results in the formation of homoatomic As-As bonds. Upon the addition of Ag, a small proportion of Ag-As bonds (N(AgAs)≈0.3) are formed in all three ternary compositions, while the direct Ag-Ag bonds (N(AgAg)≈ 0.4) appear only in the glass with the highest Ag content (12 at.%). Similar to the g- As(2)S(3) binary, the mean coordination number of arsenic is close to three, and that of sulfur is close to two, in the As(2)S(3)-Ag ternary glasses. The first sharp diffraction peak on the total structure factors of As(2)S(3) binary and (As(0.4)S(0.6))(100-x)Ag(x) ternary glasses is related to the As-As and As-S correlations.
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Affiliation(s)
- I Kaban
- Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
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Rousar T, Pařík P, Kucera O, Bartos M, Červinková Z. Glutathione reductase is inhibited by acetaminophen-glutathione conjugate in vitro. Physiol Res 2009; 59:225-232. [PMID: 19537930 DOI: 10.33549/physiolres.931744] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of the present work was to investigate a new mechanism likely contributing to the toxic action of acetaminophen, especially to explore the possible inhibition of glutathione reductase through an acetaminophen-glutathione conjugate (APAP-SG). APAP-SG conjugate was synthesized by organic synthesis and purified by column chromatography. The inhibitory effect of the conjugate on two types of glutathione reductase (from yeasts and rat hepatocytes) was tested spectro-photometrically. We found that the enzyme activity was reduced similarly after the treatment with 2.96 mM acetaminophen-glutathione conjugate in both yeast and hepatocyte glutathione reductases (GR); the enzyme activity was inhibited to 52.7+/-1.5 % (2.4+/-0.3 mU/ml) in yeast GR (control activity was 5.6+/-0.3 mU/ml) and to 48.1+/-8.8 % (2.2+/-0.2 mU/ml) in rat hepatocytes lysate GR (control activity was 5.2+/-0.2 mU/ml). In addition, the enzyme activity (from hepatocytes lysate) was decreased to 79+/-7 %, 67+/-2 % and 39+/-7 %, in 0.37, 1.48 and 3.7 mM concentration of the conjugate, respectively. We found that glutathione reductase, the essential enzyme of the antioxidant system, was dose-dependently inhibited by the product of acetaminophen metabolism - the conjugate of acetaminophen and glutathione.
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Affiliation(s)
- T Rousar
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University in Prague, Hradec Králové, Czech Republic.
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Rehak S, Maisnar V, Malek V, Cesak T, Ryska P, Bartos M, Talab R. Diagnosis and surgical therapy of plasma cell neoplasia of the spine. Neoplasma 2009; 56:84-7. [DOI: 10.4149/neo_2009_01_84] [Citation(s) in RCA: 6] [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: 11/08/2022]
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Rehák S, Krajina A, Ungermann L, Ryska P, Cerný V, Taláb R, Kanta M, Bartos M. The role of embolization in radical surgery of renal cell carcinoma spinal metastases. Acta Neurochir (Wien) 2008; 150:1177-81; discussion 1181. [PMID: 18958386 DOI: 10.1007/s00701-008-0031-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Accepted: 07/30/2008] [Indexed: 11/28/2022]
Abstract
BACKGROUND Radical surgery of renal cell carcinoma spinal metastases carries a high risk due to potentially life-threatening extreme blood loss. Radical preoperative embolization of renal cell carcinoma metastases alone is not necessarily a guarantee of extreme blood loss not occurring during operation. METHODS A retrospective analysis of 15 patients following radical surgery for a spinal metastases of a renal cell carcinoma was performed. Eight patients were embolized preoperatively and 7 were not. We analysed features influencing peroperative blood loss: size and extent of tumour, complexity of surgical approaches and radicality of embolization. RESULTS The embolized and non embolized groups were not comparable before treatment. They differed markedly in size of tumour as well as the complexity of approach. In the embolized group the size of the tumour was, on average, twice as large as that in non embolized patients and more complex approaches were used twice as frequently. Despite findings suggesting that embolization was effective, blood loss was greater in the embolized group of 8 patients (4750 ml), compared to the non-embolized group of 7 patients (1786 ml). CONCLUSION Metastasis size, extent of tumour, technical complexity of surgery and the completeness of preoperative embolization had an important effect on the amount of peroperative blood loss. The evaluation of the benefits of preoperative embolization only on the basis of blood loss is not an adequate method.
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Affiliation(s)
- S Rehák
- Department of Neurosurgery, Charles University, Teaching Hospital, Hradec Kralove, Czech Republic.
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45
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Hosek J, Bartosová L, Gregor P, Kolorz M, Díte P, Bátovský M, Bartos M. Frequency of representative single nucleotide polymorphisms associated with inflammatory bowel disease in the Czech Republic and Slovak Republic. Folia Biol (Praha) 2008; 54:88-96. [PMID: 18647548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Involvement of genetic factors in the aetiology of inflammatory bowel disease (IBD) has been known for a long time. Our aim was to investigate the prevalence of polymorphisms in NOD2, ICAM-1 and CCR5 genes in Czech and Slovak patients with IBD in comparison with healthy controls. The frequency of well-known mutations (R702W, G908W and 1007fs in the NOD2 gene; K469E in the ICAM-1 gene, and Delta32 in the CCR5 gene) involved in IBD was tested in 45 patients with CD and 22 patients with UC. The allele frequency of these mutations was determined and genotype-phenotype correlation was specified. Isolated DNA was genotyped, and allele frequency was counted and statistically verified. Significant differences between the healthy control group and CD patients were observed in mutation 1007fs of the NOD2 gene (P = 0.0203). We also associated allele E469 of the ICAM-1 gene with CD (P = 0.0024). No significant association between other alleles and CD was found, and no gene variation was linked to UC. The number of mutations and mutated genes was higher among patients with CD than among patients with UC. Our results support previous findings about participation of mutations of NOD2 and ICAM-1 genes in IBD. We confirmed that both CD and UC are polygenic diseases with a genedosage effect. This observation strengthens the opinion that genetic factors play a more important role in CD than in UC.
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Affiliation(s)
- J Hosek
- Department of Nature Pharmaceuticals, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
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Lochmanová J, Bartos M. [RNA interference and molecular pathology of selected diseases]. Cas Lek Cesk 2008; 147:607-615. [PMID: 19235485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Since many people all around the world are suffering from genetic disorders, modern therapeutic approaches are focused on the search of new pharmaceutical products. These products will be able to act on the gene level, more accurately on the nucleotide sequences themselves. RNA interference (RNAi) is an evolutionary conserved process that is caused by double stranded RNA (dsRNA). MicroRNA (miRNA) and small interfering RNA (siRNA) are the most important dsRNAs, which have been identified so far. Short (19-25 bp) non-coding dsRNAs are responsible for regulation of cellular development, heterochromatin formation and genomic stability in eukaryotes. Most importantly they are able to silence cognate genes. Therefore, they can provide new insights into the gene function and pathway analysis. Furthermore, they are believed to be new potential targets for diagnosis and therapeutics, especially for the treatment of genetic disorders, which can be caused by nucleotides insertions, deletions and translocations.
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Affiliation(s)
- J Lochmanová
- Ustav prírodních léciv, Farmaceutická fakulta, Veterinární a farmaceutická univerzita, Brno.
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Hosek J, Bartos M. [Gene expression changes during insulin resistance and "diabesity" in insulin-sensitive tissues and possibilities of their regulation]. Cas Lek Cesk 2008; 147:360-366. [PMID: 18678094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Type 2 diabetes mellitus (T2DM) gains considerable and pandemic proportions and becomes noticeable problem in a social and economic sphere. In spite of all effort, exact mechanism of T2DM origin has not been elucidated yet. Studying of transcriptom is one possibility how to explain pathophysiological processes in insulin-sensitive tissues. Obtained data can serve as a base for predicting of new therapeutic targets of this disease. This overall review introduces crucial genes whose level of products changes during T2DM. The article gives notice to a diet composition, which is an important environmental factor, which is able to influence a disease outbreak. Not only the role of fats, but also influence of some plant compounds, which would be able to serve as an alternative to present prophylaxis or treatment of T2DM, have been discussed.
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Affiliation(s)
- J Hosek
- Farmaceutická fakulta, Veterinárni a farmaceutická univerzita, Brno.
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Pate M, Svara T, Gombac M, Paller T, Zolnir-Dovc M, Emersic I, Prodinger WM, Bartos M, Zdovc I, Krt B, Pavlik I, Cvetnić Z, Pogacnik M, Ocepek M. Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden. ACTA ACUST UNITED AC 2007; 53:387-92. [PMID: 17010043 DOI: 10.1111/j.1439-0450.2006.01000.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [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: 11/30/2022]
Abstract
In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.
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Affiliation(s)
- M Pate
- Institute of Microbiology and Parasitology, Vetinary Faculty, Gerbiceva, Ljubljana, Slovenia
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Abstract
Gamma frequency oscillations are thought to provide a temporal structure for information processing in the brain. They contribute to cognitive functions, such as memory formation and sensory processing, and are disturbed in some psychiatric disorders. Fast-spiking, parvalbumin-expressing, soma-inhibiting interneurons have a key role in the generation of these oscillations. Experimental analysis in the hippocampus and the neocortex reveals that synapses among these interneurons are highly specialized. Computational analysis further suggests that synaptic specialization turns interneuron networks into robust gamma frequency oscillators.
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Affiliation(s)
- Marlene Bartos
- Physiologisches Institut der Universität Freiburg, Abteilung 1, Hermann Herder Strasse 7, D-79104 Freiburg, Germany
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Fischer OA, Mátlová L, Dvorská L, Svástová P, Bartos M, Weston RT, Pavlík I. Various stages in the life cycle of syrphid flies (Eristalis tenax; diptera: Syrphidae) as potential mechanical vectors of pathogens causing mycobacterial infections in pig herds. Folia Microbiol (Praha) 2006; 51:147-53. [PMID: 16821726 DOI: 10.1007/bf02932171] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [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: 11/30/2022]
Abstract
We defined the role of the syrphid fly Eristalis tenax in the survival and transmission of mycobacteria in pigs. The conditionally pathogenic mycobacterial (CPM) species Mycobacterium chelonae was isolated from 10 % of liquid dung samples, and both M. chelonae and another CPM species M. fortuitum were isolated from 7 (78 %) of the examined E. tenax larvae collected from the same location. Mycobacteriosis of the lymph nodes of pigs from 3 infected farms was caused by M. avium subsp. avium, M. avium subsp. hominissuis, and M. fortuitum. M. avium subsp. avium and M. avium subsp. hominissuis of identical genotype and serotypes and M. fortuitum were isolated from 7 (1.9 %) larvae, 2 (7.4 %) puparia, and one (1.6 %) imago. The count of colony forming units isolated from larval skin covering (pouch) was higher (p < or = 0.01) than that isolated from the internal organs of larvae. These results showed the potential for E. tenax larvae to spread mycobacteria throughout pig herds and the surrounding environment.
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Affiliation(s)
- O A Fischer
- Veterinary Research Institute, 632 21 Brno, Czechia.
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