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Seignette K, Jamann N, Papale P, Terra H, Porneso RO, de Kraker L, van der Togt C, van der Aa M, Neering P, Ruimschotel E, Roelfsema PR, Montijn JS, Self MW, Kole MHP, Levelt CN. Experience shapes chandelier cell function and structure in the visual cortex. eLife 2024; 12:RP91153. [PMID: 38192196 PMCID: PMC10963032 DOI: 10.7554/elife.91153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
Detailed characterization of interneuron types in primary visual cortex (V1) has greatly contributed to understanding visual perception, yet the role of chandelier cells (ChCs) in visual processing remains poorly characterized. Using viral tracing we found that V1 ChCs predominantly receive monosynaptic input from local layer 5 pyramidal cells and higher-order cortical regions. Two-photon calcium imaging and convolutional neural network modeling revealed that ChCs are visually responsive but weakly selective for stimulus content. In mice running in a virtual tunnel, ChCs respond strongly to events known to elicit arousal, including locomotion and visuomotor mismatch. Repeated exposure of the mice to the virtual tunnel was accompanied by reduced visual responses of ChCs and structural plasticity of ChC boutons and axon initial segment length. Finally, ChCs only weakly inhibited pyramidal cells. These findings suggest that ChCs provide an arousal-related signal to layer 2/3 pyramidal cells that may modulate their activity and/or gate plasticity of their axon initial segments during behaviorally relevant events.
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Affiliation(s)
- Koen Seignette
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Nora Jamann
- Department of Axonal Signaling, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Biology Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Paolo Papale
- Department of Vision & Cognition, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Huub Terra
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Ralph O Porneso
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Leander de Kraker
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Chris van der Togt
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Vision & Cognition, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Maaike van der Aa
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Paul Neering
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Vision & Cognition, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Emma Ruimschotel
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Pieter R Roelfsema
- Department of Vision & Cognition, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Laboratory of Visual Brain Therapy, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la VisionParisFrance
- Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU UniversityAmsterdamNetherlands
- Department of Psychiatry, Academic Medical Center, University of AmsterdamAmsterdamNetherlands
| | - Jorrit S Montijn
- Department of Cortical Structure & Function, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Matthew W Self
- Department of Vision & Cognition, Netherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Maarten HP Kole
- Department of Axonal Signaling, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Biology Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht UniversityUtrechtNetherlands
| | - Christiaan N Levelt
- Department of Molecular Visual Plasticity, Netherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdamNetherlands
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2
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Compans B, Burrone J. Chandelier cells shine a light on the formation of GABAergic synapses. Curr Opin Neurobiol 2023; 80:102697. [PMID: 36907075 PMCID: PMC10682383 DOI: 10.1016/j.conb.2023.102697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/05/2023] [Indexed: 03/12/2023]
Abstract
Uncovering the wiring rules employed by neurons during development represents a formidable challenge with important repercussions for neurodevelopmental disorders. Chandelier cells (ChCs) are a singular GABAergic interneuron type, with a unique morphology, that have recently begun to shed light on the rules that drive the formation and plasticity of inhibitory synapses. This review will focus on the wealth of recent data charting the emergence of synapses formed by ChCs onto pyramidal cells, from the molecules involved to the plasticity of these connections during development.
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Affiliation(s)
- Benjamin Compans
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, King's College London, New Hunt's House, Guy's Hospital Campus, London, SE1 1UL, London, UK. https://twitter.com/jbneuro
| | - Juan Burrone
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, King's College London, New Hunt's House, Guy's Hospital Campus, London, SE1 1UL, London, UK.
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3
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Jung K, Choi Y, Kwon HB. Cortical control of chandelier cells in neural codes. Front Cell Neurosci 2022; 16:992409. [PMID: 36299494 PMCID: PMC9588934 DOI: 10.3389/fncel.2022.992409] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/05/2022] [Indexed: 11/28/2022] Open
Abstract
Various cortical functions arise from the dynamic interplay of excitation and inhibition. GABAergic interneurons that mediate synaptic inhibition display significant diversity in cell morphology, electrophysiology, plasticity rule, and connectivity. These heterogeneous features are thought to underlie their functional diversity. Emerging attention on specific properties of the various interneuron types has emphasized the crucial role of cell-type specific inhibition in cortical neural processing. However, knowledge is still limited on how each interneuron type forms distinct neural circuits and regulates network activity in health and disease. To dissect interneuron heterogeneity at single cell-type precision, we focus on the chandelier cell (ChC), one of the most distinctive GABAergic interneuron types that exclusively innervate the axon initial segments (AIS) of excitatory pyramidal neurons. Here we review the current understanding of the structural and functional properties of ChCs and their implications in behavioral functions, network activity, and psychiatric disorders. These findings provide insights into the distinctive roles of various single-type interneurons in cortical neural coding and the pathophysiology of cortical dysfunction.
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Wang J, Liu W, Xu W, Yang B, Cui M, Li Z, Zhang H, Jin C, Xue H, Zhang J. Comprehensive Analysis of the Oncogenic, Genomic Alteration, and Immunological Landscape of Cation-Chloride Cotransporters in Pan-Cancer. Front Oncol 2022; 12:819688. [PMID: 35372048 PMCID: PMC8968682 DOI: 10.3389/fonc.2022.819688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Background Assessing the phenotypic diversity underlying tumor progression requires the identification of variations in the respective molecular interaction in the tumor microenvironment (TME). Despite emerging studies focusing on the association between cation-chloride cotransporters (CCCs) and carcinogenesis, direct evidence that CCCs (KCC2 and NKCC1) mediate tumor progression in pan-cancer remains unclear. Methods We conducted a comprehensive assessment of the expression, DNA variation profiles, and prognostic and immunologic implications of CCCs based on a large-scale pan-cancer population, including 10,967 cancer patients from the Cancer Genome Atlas, 9,162 cancer patients from Genomics Expression Omnibus, 48,834 cancer patients from 188 independent studies, and 356 cancer patients from three real-world cohorts. Results In this study, we first found that CCCs were highly expressed in most tumors, and prominently associated with prognosis. Kaplan-Meier analysis and Cox regression analysis revealed that KCC2 and NKCC1 significantly predicted survival for patients with pan-cancer, suggesting that CCCs have inconsistent tumorigenesis regulatory mechanisms in cancers. Next, we examined the DNA variation landscape of KCC2 and NKCC1 and their prognostic implications in pan-cancer. The results demonstrated that UCEC patients with somatic copy number variation (CNV) of NKCC1 received significantly better outcomes (p < 0.05). Besides emphasizing the clinical implications of CNV of CCCs for cancer patients, we found that NKCC1MUT could prominently prolong progression-free survival (p = 2.59e-04), disease-specific survival (p = 0.019), and overall survival (p = 0.034) compared with NKCC1WT cancer patients possibly via regulation of cell proliferation and oncogenic stress pathways. Additionally, KCC2 positively correlated with the levels of tumor-infiltrating macrophages and CD4+ T cells, but NKCC1 showed a significantly widely negative association with tumor-infiltrated lymphocytes, suggesting an immune-excluded TME in cancers. Similarly, expression of KCC2, rather than NKCC1, was positively correlated with the immune checkpoint molecules, indicating its role as an immune regulator in a wide variety of cancers. Finally, to verify our hypothesis and altered expression of CCCs, we performed IHC analysis and revealed the staining distribution in tumor and adjacent normal tissues of glioma, clear cell renal cell carcinoma, papillary cell renal cell carcinoma, and hepatocellular and breast cancer from three real-world cohorts, and validated prominently prognostic implications of CCCs in patients with clear cell renal cell carcinoma. Conclusion This study first comprehensively investigated the molecular and clinical role of CCCs, and illustrated the significant association among KCC2/NKCC1 expression, DNA variation profiles prognosis, and TME of pan-cancer. The pan-cancer findings provided an in-depth understanding of potential oncogenic and immunologic of differential expression and DNA alteration of KCC2/NKCC1 cancers.
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Affiliation(s)
- Jie Wang
- Department of Anesthesiology and Perioperative Medicine, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Wangrui Liu
- Department of Neurosurgery, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Wenhao Xu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Baofeng Yang
- Department of Anesthesiology and Perioperative Medicine, Affiliate Cancer Hospital of Zhengzhou University, Zhengzhou, China
| | - Mingzhu Cui
- Department of Anesthesiology and Perioperative Medicine, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Zhen Li
- Department of Pathology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Hailiang Zhang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Chuntao Jin
- Department of Neurosurgery, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Huanzhou Xue
- Department of Hepatobiliary Surgery, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Jiaqiang Zhang
- Department of Anesthesiology and Perioperative Medicine, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou, China
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Abstract
Chandelier cells (ChCs) are a unique type of GABAergic interneuron that form axo-axonic synapses exclusively on the axon initial segment (AIS) of neocortical pyramidal neurons (PyNs), allowing them to exert powerful yet precise control over PyN firing and population output. The importance of proper ChC function is further underscored by the association of ChC connectivity defects with various neurological conditions. Despite this, the cellular mechanisms governing ChC axo-axonic synapse formation remain poorly understood. Here, we identify microglia as key regulators of ChC axonal morphogenesis and AIS synaptogenesis, and show that disease-induced aberrant microglial activation perturbs proper ChC synaptic development/connectivity in the neocortex. In doing so, such findings highlight the therapeutic potential of manipulating microglia to ensure proper brain wiring. Microglia have emerged as critical regulators of synapse development and circuit formation in the healthy brain. To date, examination of microglia in such processes has largely been focused on excitatory synapses. Their roles, however, in the modulation of GABAergic interneuron synapses—particularly those targeting the axon initial segment (AIS)—during development remain enigmatic. Here, we identify a synaptogenic/growth-promoting role for microglia in regulating pyramidal neuron (PyN) AIS synapse formation by chandelier cells (ChCs), a unique interneuron subtype whose axonal terminals, called cartridges, selectively target the AIS. We show that a subset of microglia contacts PyN AISs and ChC cartridges and that such tripartite interactions, which rely on the unique AIS cytoskeleton and microglial GABAB1 receptors, are associated with increased ChC cartridge length and bouton number and AIS synaptogenesis. Conversely, microglia depletion or disease-induced aberrant microglia activation impairs the proper development and maintenance of ChC cartridges and boutons, as well as AIS synaptogenesis. These findings unveil key roles for homeostatic, AIS-associated microglia in regulating proper ChC axonal morphogenesis and synaptic connectivity in the neocortex.
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Schneider-Mizell CM, Bodor AL, Collman F, Brittain D, Bleckert A, Dorkenwald S, Turner NL, Macrina T, Lee K, Lu R, Wu J, Zhuang J, Nandi A, Hu B, Buchanan J, Takeno MM, Torres R, Mahalingam G, Bumbarger DJ, Li Y, Chartrand T, Kemnitz N, Silversmith WM, Ih D, Zung J, Zlateski A, Tartavull I, Popovych S, Wong W, Castro M, Jordan CS, Froudarakis E, Becker L, Suckow S, Reimer J, Tolias AS, Anastassiou CA, Seung HS, Reid RC, da Costa NM. Structure and function of axo-axonic inhibition. eLife 2021; 10:e73783. [PMID: 34851292 PMCID: PMC8758143 DOI: 10.7554/elife.73783] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Inhibitory neurons in mammalian cortex exhibit diverse physiological, morphological, molecular, and connectivity signatures. While considerable work has measured the average connectivity of several interneuron classes, there remains a fundamental lack of understanding of the connectivity distribution of distinct inhibitory cell types with synaptic resolution, how it relates to properties of target cells, and how it affects function. Here, we used large-scale electron microscopy and functional imaging to address these questions for chandelier cells in layer 2/3 of the mouse visual cortex. With dense reconstructions from electron microscopy, we mapped the complete chandelier input onto 153 pyramidal neurons. We found that synapse number is highly variable across the population and is correlated with several structural features of the target neuron. This variability in the number of axo-axonic ChC synapses is higher than the variability seen in perisomatic inhibition. Biophysical simulations show that the observed pattern of axo-axonic inhibition is particularly effective in controlling excitatory output when excitation and inhibition are co-active. Finally, we measured chandelier cell activity in awake animals using a cell-type-specific calcium imaging approach and saw highly correlated activity across chandelier cells. In the same experiments, in vivo chandelier population activity correlated with pupil dilation, a proxy for arousal. Together, these results suggest that chandelier cells provide a circuit-wide signal whose strength is adjusted relative to the properties of target neurons.
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Affiliation(s)
| | - Agnes L Bodor
- Allen Institute for Brain SciencesSeattleUnited States
| | | | | | - Adam Bleckert
- Allen Institute for Brain SciencesSeattleUnited States
| | - Sven Dorkenwald
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Nicholas L Turner
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Thomas Macrina
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Kisuk Lee
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Brain & Cognitive Sciences Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Ran Lu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jingpeng Wu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jun Zhuang
- Allen Institute for Brain SciencesSeattleUnited States
| | - Anirban Nandi
- Allen Institute for Brain SciencesSeattleUnited States
| | - Brian Hu
- Allen Institute for Brain SciencesSeattleUnited States
| | | | - Marc M Takeno
- Allen Institute for Brain SciencesSeattleUnited States
| | - Russel Torres
- Allen Institute for Brain SciencesSeattleUnited States
| | | | | | - Yang Li
- Allen Institute for Brain SciencesSeattleUnited States
| | | | - Nico Kemnitz
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | | | - Dodam Ih
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jonathan Zung
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Aleksandar Zlateski
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Ignacio Tartavull
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Sergiy Popovych
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - William Wong
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Manuel Castro
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Chris S Jordan
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Emmanouil Froudarakis
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
| | - Lynne Becker
- Allen Institute for Brain SciencesSeattleUnited States
| | - Shelby Suckow
- Allen Institute for Brain SciencesSeattleUnited States
| | - Jacob Reimer
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
| | - Andreas S Tolias
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
- Department of Electrical and Computer Engineering, Rice UniversityHoustonUnited States
| | - Costas A Anastassiou
- Allen Institute for Brain SciencesSeattleUnited States
- Department of Neurology, University of British ColumbiaVancouverCanada
| | - H Sebastian Seung
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - R Clay Reid
- Allen Institute for Brain SciencesSeattleUnited States
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Newton TH, Reimann MW, Abdellah M, Chevtchenko G, Muller EB, Markram H. In silico voltage-sensitive dye imaging reveals the emergent dynamics of cortical populations. Nat Commun 2021; 12:3630. [PMID: 34131136 PMCID: PMC8206372 DOI: 10.1038/s41467-021-23901-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 05/19/2021] [Indexed: 11/08/2022] Open
Abstract
Voltage-sensitive dye imaging (VSDI) is a powerful technique for interrogating membrane potential dynamics in assemblies of cortical neurons, but with effective resolution limits that confound interpretation. To address this limitation, we developed an in silico model of VSDI in a biologically faithful digital reconstruction of rodent neocortical microcircuitry. Using this model, we extend previous experimental observations regarding the cellular origins of VSDI, finding that the signal is driven primarily by neurons in layers 2/3 and 5, and that VSDI measurements do not capture individual spikes. Furthermore, we test the capacity of VSD image sequences to discriminate between afferent thalamic inputs at various spatial locations to estimate a lower bound on the functional resolution of VSDI. Our approach underscores the power of a bottom-up computational approach for relating scales of cortical processing.
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Affiliation(s)
- Taylor H Newton
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland.
- IT'IS Foundation for Research on Information Technologies in Society, Zurich, Switzerland.
| | - Michael W Reimann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Marwan Abdellah
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Grigori Chevtchenko
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Eilif B Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- CHU Sainte-Justine Research Center, Montreal, QC, Canada
- Quebec Artificial Intelligence Institute (Mila), Montreal, QC, Canada
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, Lausanne, Switzerland
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8
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Franken TP, Bondy BJ, Haimes DB, Goldwyn JH, Golding NL, Smith PH, Joris PX. Glycinergic axonal inhibition subserves acute spatial sensitivity to sudden increases in sound intensity. eLife 2021; 10:62183. [PMID: 34121662 PMCID: PMC8238506 DOI: 10.7554/elife.62183] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 06/12/2021] [Indexed: 11/20/2022] Open
Abstract
Locomotion generates adventitious sounds which enable detection and localization of predators and prey. Such sounds contain brisk changes or transients in amplitude. We investigated the hypothesis that ill-understood temporal specializations in binaural circuits subserve lateralization of such sound transients, based on different time of arrival at the ears (interaural time differences, ITDs). We find that Lateral Superior Olive (LSO) neurons show exquisite ITD-sensitivity, reflecting extreme precision and reliability of excitatory and inhibitory postsynaptic potentials, in contrast to Medial Superior Olive neurons, traditionally viewed as the ultimate ITD-detectors. In vivo, inhibition blocks LSO excitation over an extremely short window, which, in vitro, required synaptically evoked inhibition. Light and electron microscopy revealed inhibitory synapses on the axon initial segment as the structural basis of this observation. These results reveal a neural vetoing mechanism with extreme temporal and spatial precision and establish the LSO as the primary nucleus for binaural processing of sound transients.
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Affiliation(s)
- Tom P Franken
- Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium.,Systems Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| | - Brian J Bondy
- Department of Neuroscience, University of Texas at Austin, Austin, United States
| | - David B Haimes
- Department of Neuroscience, University of Texas at Austin, Austin, United States
| | - Joshua H Goldwyn
- Department of Mathematics and Statistics, Swarthmore College, Swarthmore, United States
| | - Nace L Golding
- Department of Neuroscience, University of Texas at Austin, Austin, United States
| | - Philip H Smith
- Department of Neuroscience, University of Wisconsin-Madison, Madison, United States
| | - Philip X Joris
- Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
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9
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Perumal MB, Latimer B, Xu L, Stratton P, Nair S, Sah P. Microcircuit mechanisms for the generation of sharp-wave ripples in the basolateral amygdala: A role for chandelier interneurons. Cell Rep 2021; 35:109106. [PMID: 33979609 PMCID: PMC9136954 DOI: 10.1016/j.celrep.2021.109106] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/22/2021] [Accepted: 04/18/2021] [Indexed: 01/11/2023] Open
Abstract
Synchronized activity in neural circuits, detected as oscillations in the extracellular field potential, has been associated with learning and memory. Neural circuits in the basolateral amygdala (BLA), a mid-temporal lobe structure, generate oscillations in specific frequency bands to mediate emotional memory functions. However, how BLA circuits generate oscillations in distinct frequency bands is not known. Of these, sharp-waves (SWs) are repetitive, brief transitions that contain a low-frequency (<20 Hz) envelope, often coupled with ripples (100–300 Hz), have been associated with memory consolidation. Here, we show that SWs are retained in the BLA ex vivo and generated by local circuits. We demonstrate that an action potential in a chandelier interneuron is sufficient to initiate SWs through local circuits. Using a physiologically constrained model, we show that microcircuits organized as chandelier-interneuron-driven modules reproduce SWs and associated cellular events, revealing a functional role for chandelier interneurons and microcircuits for SW generation. Perumal et al. investigate circuits that generate network oscillations called sharp waves (SWs) in the basolateral amygdala. They show that discharge in a chandelier interneuron can initiate SW oscillations—a network activity associated with memory consolidation. They develop a network model with chandelier-interneuron-driven modular microcircuits for SW generation.
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Affiliation(s)
| | - Benjamin Latimer
- Electrical Engineering & Computer Science, University of Missouri, Columbia, MO 65211 USA
| | - Li Xu
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Peter Stratton
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Satish Nair
- Electrical Engineering & Computer Science, University of Missouri, Columbia, MO 65211 USA
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia; Joint Center for Neuroscience and Neural Engineering and Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong Province 518055, P.R. China.
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10
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Wang BS, Bernardez Sarria MS, An X, He M, Alam NM, Prusky GT, Crair MC, Huang ZJ. Retinal and Callosal Activity-Dependent Chandelier Cell Elimination Shapes Binocularity in Primary Visual Cortex. Neuron 2021; 109:502-515.e7. [PMID: 33290732 PMCID: PMC7943176 DOI: 10.1016/j.neuron.2020.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/23/2020] [Accepted: 11/04/2020] [Indexed: 12/21/2022]
Abstract
In mammals with binocular vision, integration of the left and right visual scene relies on information in the center visual field, which are relayed from each retina in parallel and merge in the primary visual cortex (V1) through the convergence of ipsi- and contralateral geniculocortical inputs as well as transcallosal projections between two visual cortices. The developmental assembly of this binocular circuit, especially the transcallosal pathway, remains incompletely understood. Using genetic methods in mice, we found that several days before eye-opening, retinal and callosal activities drive massive apoptosis of GABAergic chandelier cells (ChCs) in the binocular region of V1. Blockade of ChC elimination resulted in a contralateral eye-dominated V1 and deficient binocular vision. As pre-vision retinal activities convey the left-right organization of the visual field, their regulation of ChC density through the transcallosal pathway may prime a nascent binocular territory for subsequent experience-driven tuning during the post-vision critical period.
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Affiliation(s)
- Bor-Shuen Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Maria Sol Bernardez Sarria
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Xu An
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Miao He
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Nazia M Alam
- The Burke Neurological Institute, White Plains, NY 10605, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Glen T Prusky
- The Burke Neurological Institute, White Plains, NY 10605, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Michael C Crair
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.
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11
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Gour A, Boergens KM, Heike N, Hua Y, Laserstein P, Song K, Helmstaedter M. Postnatal connectomic development of inhibition in mouse barrel cortex. Science 2020; 371:science.abb4534. [PMID: 33273061 DOI: 10.1126/science.abb4534] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022]
Abstract
Brain circuits in the neocortex develop from diverse types of neurons that migrate and form synapses. Here we quantify the circuit patterns of synaptogenesis for inhibitory interneurons in the developing mouse somatosensory cortex. We studied synaptic innervation of cell bodies, apical dendrites, and axon initial segments using three-dimensional electron microscopy focusing on the first 4 weeks postnatally (postnatal days P5 to P28). We found that innervation of apical dendrites occurs early and specifically: Target preference is already almost at adult levels at P5. Axons innervating cell bodies, on the other hand, gradually acquire specificity from P5 to P9, likely via synaptic overabundance followed by antispecific synapse removal. Chandelier axons show first target preference by P14 but develop full target specificity almost completely by P28, which is consistent with a combination of axon outgrowth and off-target synapse removal. This connectomic developmental profile reveals how inhibitory axons in the mouse cortex establish brain circuitry during development.
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Affiliation(s)
- Anjali Gour
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Kevin M Boergens
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Natalie Heike
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Yunfeng Hua
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Philip Laserstein
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Kun Song
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Moritz Helmstaedter
- Department of Connectomics, Max Planck Institute for Brain Research, Frankfurt, Germany.
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12
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Kwon T, Merchán-Pérez A, Rial Verde EM, Rodríguez JR, DeFelipe J, Yuste R. Ultrastructural, Molecular and Functional Mapping of GABAergic Synapses on Dendritic Spines and Shafts of Neocortical Pyramidal Neurons. Cereb Cortex 2020; 29:2771-2781. [PMID: 30113619 DOI: 10.1093/cercor/bhy143] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/15/2018] [Indexed: 01/25/2023] Open
Abstract
The location of GABAergic synapses on dendrites is likely key for neuronal integration. In particular, inhibitory inputs on dendritic spines could serve to selectively veto or modulate individual excitatory inputs, greatly expanding the computational power of individual neurons. To investigate this, we have undertaken a combined functional, molecular, and ultrastructural mapping of the location of GABAergic inputs onto dendrites of pyramidal neurons from upper layers of juvenile mouse somatosensory cortex. Using two-photon uncaging of GABA, intracellular labeling with gerphyrin intrabodies, and focused ion beam milling with scanning electron microscopy, we find that most (96-98%) spines lack GABAergic synapses, although they still display GABAergic responses, potentially due to extrasynaptic GABA receptors. We conclude that GABAergic inputs, in practice, contact dendritic shafts and likely control clusters of excitatory inputs, defining functional zones on dendrites.
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Affiliation(s)
- Taekyung Kwon
- Department of Biological Sciences, Neurotechnology Center, Columbia University, NY, USA
| | - Angel Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid, Spain
| | - Emiliano M Rial Verde
- Department of Biological Sciences, Neurotechnology Center, Columbia University, NY, USA
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Rafael Yuste
- Department of Biological Sciences, Neurotechnology Center, Columbia University, NY, USA
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13
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Gallo NB, Paul A, Van Aelst L. Shedding Light on Chandelier Cell Development, Connectivity, and Contribution to Neural Disorders. Trends Neurosci 2020; 43:565-580. [PMID: 32564887 PMCID: PMC7392791 DOI: 10.1016/j.tins.2020.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/06/2020] [Accepted: 05/07/2020] [Indexed: 02/04/2023]
Abstract
Chandelier cells (ChCs) are a unique type of GABAergic interneuron that selectively innervate the axon initial segment (AIS) of excitatory pyramidal neurons; the subcellular domain where action potentials are initiated. The proper genesis and maturation of ChCs is critical for regulating neural ensemble firing in the neocortex throughout development and adulthood. Recently, genetic and molecular studies have shed new light on the complex innerworkings of ChCs in health and disease. This review presents an overview of recent studies on the developmental origins, migratory properties, and morphology of ChCs. In addition, attention is given to newly identified molecules regulating ChC morphogenesis and connectivity as well as recent work linking ChC dysfunction to neural disorders, including schizophrenia, epilepsy, and autism spectrum disorder (ASD).
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Affiliation(s)
- Nicholas B Gallo
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, 11724, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Anirban Paul
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Linda Van Aelst
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, 11724, USA.
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14
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Abstract
Cortical interneurons display striking differences in shape, physiology, and other attributes, challenging us to appropriately classify them. We previously suggested that interneuron types should be defined by their role in cortical processing. Here, we revisit the question of how to codify their diversity based upon their division of labor and function as controllers of cortical information flow. We suggest that developmental trajectories provide a guide for appreciating interneuron diversity and argue that subtype identity is generated using a configurational (rather than combinatorial) code of transcription factors that produce attractor states in the underlying gene regulatory network. We present our updated three-stage model for interneuron specification: an initial cardinal step, allocating interneurons into a few major classes, followed by definitive refinement, creating subclasses upon settling within the cortex, and lastly, state determination, reflecting the incorporation of interneurons into functional circuit ensembles. We close by discussing findings indicating that major interneuron classes are both evolutionarily ancient and conserved. We propose that the complexity of cortical circuits is generated by phylogenetically old interneuron types, complemented by an evolutionary increase in principal neuron diversity. This suggests that a natural neurobiological definition of interneuron types might be derived from a match between their developmental origin and computational function.
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Affiliation(s)
- Gord Fishell
- Department of Neurobiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA;
- Stanley Center for Psychiatric Research, Broad Institute, Cambridge, Massachusetts 02142, USA
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Adam Kepecs
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri 63130, USA;
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15
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Pan-Vazquez A, Wefelmeyer W, Gonzalez Sabater V, Neves G, Burrone J. Activity-Dependent Plasticity of Axo-axonic Synapses at the Axon Initial Segment. Neuron 2020; 106:265-276.e6. [PMID: 32109363 PMCID: PMC7181187 DOI: 10.1016/j.neuron.2020.01.037] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 12/06/2019] [Accepted: 01/27/2020] [Indexed: 12/20/2022]
Abstract
The activity-dependent rules that govern the wiring of GABAergic interneurons are not well understood. Chandelier cells (ChCs) are a type of GABAergic interneuron that control pyramidal cell output through axo-axonic synapses that target the axon initial segment. In vivo imaging of ChCs during development uncovered a narrow window (P12-P18) over which axons arborized and formed connections. We found that increases in the activity of either pyramidal cells or individual ChCs during this temporal window result in a reversible decrease in axo-axonic connections. Voltage imaging of GABAergic transmission at the axon initial segment (AIS) showed that axo-axonic synapses were depolarizing during this period. Identical manipulations of network activity in older mice (P40-P46), when ChC synapses are inhibitory, resulted instead in an increase in axo-axonic synapses. We propose that the direction of ChC synaptic plasticity follows homeostatic rules that depend on the polarity of axo-axonic synapses.
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Affiliation(s)
- Alejandro Pan-Vazquez
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Winnie Wefelmeyer
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Victoria Gonzalez Sabater
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Guilherme Neves
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0FA, UK
| | - Juan Burrone
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK.
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16
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The Role of Parvalbumin-positive Interneurons in Auditory Steady-State Response Deficits in Schizophrenia. Sci Rep 2019; 9:18525. [PMID: 31811155 PMCID: PMC6898379 DOI: 10.1038/s41598-019-53682-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/12/2019] [Indexed: 12/19/2022] Open
Abstract
Despite an increasing body of evidence demonstrating subcellular alterations in parvalbumin-positive (PV+) interneurons in schizophrenia, their functional consequences remain elusive. Since PV+ interneurons are involved in the generation of fast cortical rhythms, these changes have been hypothesized to contribute to well-established alterations of beta and gamma range oscillations in patients suffering from schizophrenia. However, the precise role of these alterations and the role of different subtypes of PV+ interneurons is still unclear. Here we used a computational model of auditory steady-state response (ASSR) deficits in schizophrenia. We investigated the differential effects of decelerated synaptic dynamics, caused by subcellular alterations at two subtypes of PV+ interneurons: basket cells and chandelier cells. Our simulations suggest that subcellular alterations at basket cell synapses rather than chandelier cell synapses are the main contributor to these deficits. Particularly, basket cells might serve as target for innovative therapeutic interventions aiming at reversing the oscillatory deficits.
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17
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Krajcovic B, Fajnerova I, Horacek J, Kelemen E, Kubik S, Svoboda J, Stuchlik A. Neural and neuronal discoordination in schizophrenia: From ensembles through networks to symptoms. Acta Physiol (Oxf) 2019; 226:e13282. [PMID: 31002202 DOI: 10.1111/apha.13282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/22/2022]
Abstract
Despite the substantial knowledge accumulated by past research, the exact mechanisms of the pathogenesis of schizophrenia and causal treatments still remain unclear. Deficits of cognition and information processing in schizophrenia are today often viewed as the primary and core symptoms of this devastating disorder. These deficits likely result from disruptions in the coordination of neuronal and neural activity. The aim of this review is to bring together convergent evidence of discoordinated brain circuits in schizophrenia at multiple levels of resolution, ranging from principal cells and interneurons, neuronal ensembles and local circuits, to large-scale brain networks. We show how these aberrations could underlie deficits in cognitive control and other higher order cognitive-behavioural functions. Converging evidence from both animal models and patients with schizophrenia is presented in an effort to gain insight into common features of deficits in the brain information processing in this disorder, marked by disruption of several neurotransmitter and signalling systems and severe behavioural outcomes.
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Affiliation(s)
- Branislav Krajcovic
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Third Faculty of Medicine Charles University Prague Czech Republic
| | - Iveta Fajnerova
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Jiri Horacek
- Third Faculty of Medicine Charles University Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Eduard Kelemen
- Research Programme 1 - Experimental Neurobiology National Institute of Mental Health Klecany Czech Republic
| | - Stepan Kubik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Jan Svoboda
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ales Stuchlik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
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18
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Jia Y, Chen L, Chi D, Cong D, Zhou P, Jin J, Ji H, Liang B, Gao S, Hu S. Photodynamic therapy combined with temozolomide inhibits C6 glioma migration and invasion and promotes mitochondrial-associated apoptosis by inhibiting sodium-hydrogen exchanger isoform 1. Photodiagnosis Photodyn Ther 2019; 26:405-412. [PMID: 31085295 DOI: 10.1016/j.pdpdt.2019.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/23/2019] [Accepted: 05/09/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE As a targeted therapeutic technique for glioma inhibition, photodynamic therapy (PDT) has gradually become a focus of basic research related to glioma treatment. The capacity of PDT to kill glioma cells involves varieties of pathways. In glioma cells, activated sodium-hydrogen exchanger isoform 1 (NHE1) can inhibit the cytotoxic effect of temozolomide (TMZ), promote cell migration and invasion, and inhibit cell apoptosis by changing the acid-base equilibrium. The purpose of our study was to explore if PDT combined with TMZ can effectively inhibit glioma cells by influencing NHE1 in vitro. METHODS We analyzed the expression levels of proteins such as NHE1, ezrin, vimentin, Bcl-2, and Bax by Western blot analysis, we assessed the migration and invasion of rat C6 glioma cells by Transwell assay, and we evaluated C6 cell apoptosis in vitro by flow cytometry. RESULTS Western blot results indicated that NHE1, ezrin and vimentin were downregulated after cotreatment of C6 cells, and intracellular acidification was detected by a fluorometric intracellular pH assay. The migration and invasion capacities of C6 cells were significantly hindered after cotreatment, as shown by the Transwell assay. Experimental data also revealed a significant increase in cell apoptosis after cotreatment, as detected by flow cytometry; corresponding proapoptotic changes in Bcl-2, Bax and caspase-3 were also observed in vitro. CONCLUSION These results demonstrate that PDT combined with TMZ can inhibit C6 cell migration and invasion and promote mitochondrial-associated apoptosis by inhibiting NHE1. Therefore, this study provides supporting evidence for a potential method for the treatment of glioma.
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Affiliation(s)
- Yulong Jia
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Lei Chen
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Dapeng Chi
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Damin Cong
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Peng Zhou
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Jiaqi Jin
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Hang Ji
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Binbin Liang
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Shuai Gao
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China
| | - Shaoshan Hu
- Department of Neurological Surgery, The Second Affiliated Hospital of the Harbin Medical University, Harbin, 150001, China.
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19
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Wang X, Tucciarone J, Jiang S, Yin F, Wang BS, Wang D, Jia Y, Jia X, Li Y, Yang T, Xu Z, Akram MA, Wang Y, Zeng S, Ascoli GA, Mitra P, Gong H, Luo Q, Huang ZJ. Genetic Single Neuron Anatomy Reveals Fine Granularity of Cortical Axo-Axonic Cells. Cell Rep 2019; 26:3145-3159.e5. [PMID: 30865900 PMCID: PMC7863572 DOI: 10.1016/j.celrep.2019.02.040] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 11/19/2018] [Accepted: 02/08/2019] [Indexed: 10/27/2022] Open
Abstract
Parsing diverse nerve cells into biological types is necessary for understanding neural circuit organization. Morphology is an intuitive criterion for neuronal classification and a proxy of connectivity, but morphological diversity and variability often preclude resolving the granularity of neuron types. Combining genetic labeling with high-resolution, large-volume light microscopy, we established a single neuron anatomy platform that resolves, registers, and quantifies complete neuron morphologies in the mouse brain. We discovered that cortical axo-axonic cells (AACs), a cardinal GABAergic interneuron type that controls pyramidal neuron (PyN) spiking at axon initial segments, consist of multiple subtypes distinguished by highly laminar-specific soma position and dendritic and axonal arborization patterns. Whereas the laminar arrangements of AAC dendrites reflect differential recruitment by input streams, the laminar distribution and local geometry of AAC axons enable differential innervation of PyN ensembles. This platform will facilitate genetically targeted, high-resolution, and scalable single neuron anatomy in the mouse brain.
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Affiliation(s)
- Xiaojun Wang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jason Tucciarone
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Program in Neuroscience and Medical Scientist Training Program, Stony Brook University, Stony Brook, NY 11790, USA
| | - Siqi Jiang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Fangfang Yin
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bor-Shuen Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Dingkang Wang
- Computer Science and Engineering Department, The Ohio State University, Columbus, OH 43221, USA
| | - Yao Jia
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xueyan Jia
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yuxin Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Yang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zhengchao Xu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Masood A Akram
- Center for Neural Informatics, Structures, and Plasticity, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Yusu Wang
- Computer Science and Engineering Department, The Ohio State University, Columbus, OH 43221, USA
| | - Shaoqun Zeng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Giorgio A Ascoli
- Center for Neural Informatics, Structures, and Plasticity, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Partha Mitra
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
| | - Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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20
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Tai Y, Gallo NB, Wang M, Yu JR, Van Aelst L. Axo-axonic Innervation of Neocortical Pyramidal Neurons by GABAergic Chandelier Cells Requires AnkyrinG-Associated L1CAM. Neuron 2019; 102:358-372.e9. [PMID: 30846310 DOI: 10.1016/j.neuron.2019.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/20/2018] [Accepted: 02/04/2019] [Indexed: 11/17/2022]
Abstract
Among the diverse interneuron subtypes in the neocortex, chandelier cells (ChCs) are the only population that selectively innervate pyramidal neurons (PyNs) at their axon initial segment (AIS), the site of action potential initiation, allowing them to exert powerful control over PyN output. Yet, mechanisms underlying their subcellular innervation of PyN AISs are unknown. To identify molecular determinants of ChC/PyN AIS innervation, we performed an in vivo RNAi screen of PyN-expressed axonal cell adhesion molecules (CAMs) and select Ephs/ephrins. Strikingly, we found the L1 family member L1CAM to be the only molecule required for ChC/PyN AIS innervation. Further, we show that L1CAM is required during both the establishment and maintenance of innervation, and that selective innervation of PyN AISs by ChCs requires AIS anchoring of L1CAM by the cytoskeletal ankyrin-G/βIV-spectrin complex. Thus, our findings identify PyN-expressed L1CAM as a critical CAM required for innervation of neocortical PyN AISs by ChCs. VIDEO ABSTRACT.
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Affiliation(s)
- Yilin Tai
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Nicholas B Gallo
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Minghui Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Jia-Ray Yu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Linda Van Aelst
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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21
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Progressive divisions of multipotent neural progenitors generate late-born chandelier cells in the neocortex. Nat Commun 2018; 9:4595. [PMID: 30389944 PMCID: PMC6214958 DOI: 10.1038/s41467-018-07055-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/02/2018] [Indexed: 01/12/2023] Open
Abstract
Diverse γ-aminobutyric acid (GABA)-ergic interneurons provide different modes of inhibition to support circuit operation in the neocortex. However, the cellular and molecular mechanisms underlying the systematic generation of assorted neocortical interneurons remain largely unclear. Here we show that NKX2.1-expressing radial glial progenitors (RGPs) in the mouse embryonic ventral telencephalon divide progressively to generate distinct groups of interneurons, which occupy the neocortex in a time-dependent, early inside-out and late outside-in, manner. Notably, the late-born chandelier cells, one of the morphologically and physiologically highly distinguishable GABAergic interneurons, arise reliably from continuously dividing RGPs that produce non-chandelier cells initially. Selective removal of Partition defective 3, an evolutionarily conserved cell polarity protein, impairs RGP asymmetric cell division, resulting in premature depletion of RGPs towards the late embryonic stages and a consequent loss of chandelier cells. These results suggest that consecutive asymmetric divisions of multipotent RGPs generate diverse neocortical interneurons in a progressive manner. Diverse GABAergic neurons arise from progenitors in the medial ganglionic eminence. Here, the authors show these progenitors are progressively fate-restricted, with early-born interneurons occupying cortex in an “inside-out” pattern and later-born types like chandelier cells generated “outside-in”.
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22
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Barbas H, Wang J, Joyce MKP, García-Cabezas MÁ. Pathway mechanism for excitatory and inhibitory control in working memory. J Neurophysiol 2018; 120:2659-2678. [PMID: 30256740 DOI: 10.1152/jn.00936.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Humans engage in many daily activities that rely on working memory, the ability to hold and sequence information temporarily to accomplish a task. We focus on the process of working memory, based on circuit mechanisms for attending to relevant signals and suppressing irrelevant stimuli. We discuss that connections critically depend on the systematic variation in laminar structure across all cortical systems. Laminar structure is used to group areas into types regardless of their placement in the cortex, ranging from low-type agranular areas that lack layer IV to high-type areas that have six well-delineated layers. Connections vary in laminar distribution and strength based on the difference in type between linked areas, according to the "structural model" (Barbas H, Rempel-Clower N. Cereb Cortex 7: 635-646, 1997). The many possible pathways thus vary systematically by laminar distribution and strength, and they interface with excitatory neurons to select relevant stimuli and with functionally distinct inhibitory neurons that suppress activity at the site of termination. Using prefrontal pathways, we discuss how systematic architectonic variation gives rise to diverse pathways that can be recruited, along with amygdalar and hippocampal pathways that provide sensory, affective, and contextual information. The prefrontal cortex is also connected with thalamic nuclei that receive the output of the basal ganglia and cerebellum, which may facilitate fast sequencing of information. The complement of connections and their interface with distinct inhibitory neurons allows dynamic recruitment of areas and shifts in cortical rhythms to meet rapidly changing demands of sequential components of working memory tasks.
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Affiliation(s)
- Helen Barbas
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts.,Graduate Program in Neuroscience, Boston University , Boston, Massachusetts
| | - Jingyi Wang
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts
| | - Mary Kate P Joyce
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Graduate Program in Neuroscience, Boston University , Boston, Massachusetts
| | - Miguel Ángel García-Cabezas
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts
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23
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Schlüter A, Del Turco D, Deller T, Gutzmann A, Schultz C, Engelhardt M. Structural Plasticity of Synaptopodin in the Axon Initial Segment during Visual Cortex Development. Cereb Cortex 2018; 27:4662-4675. [PMID: 28922860 DOI: 10.1093/cercor/bhx208] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Indexed: 12/12/2022] Open
Abstract
The axon initial segment (AIS) is essential for action potential generation. Recently, the AIS was identified as a site of neuronal plasticity. A subpopulation of AIS in cortical principal neurons contains stacks of endoplasmic reticulum (ER) forming the cisternal organelle (CO). The function of this organelle is poorly understood, but roles in local Ca2+-trafficking and AIS plasticity are discussed. To investigate whether the presence and/or the size of COs are linked to the development and maturation of AIS of cortical neurons, we analyzed the relationship between COs and the AIS during visual cortex development under control and visual deprivation conditions. In wildtype mice, immunolabeling for synaptopodin, ankyrin-G, and ßIV-spectrin were employed to label COs and the AIS, respectively. Dark rearing resulted in an increase in synaptopodin cluster sizes, suggesting a homeostatic function of the CO in this cellular compartment. In line with this observation, synaptopodin-deficient mice lacking the CO showed AIS shortening in the dark. Collectively, these data demonstrate that the CO is an essential part of the AIS machinery required for AIS plasticity during a critical developmental period of the visual cortex.
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Affiliation(s)
- Annabelle Schlüter
- Institute of Neuroanatomy, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany.,Department of Neurobiology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Annika Gutzmann
- Institute of Neuroanatomy, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Christian Schultz
- Institute of Neuroanatomy, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Maren Engelhardt
- Institute of Neuroanatomy, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
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24
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Chandelier Cells Illuminate Inhibitory Control of Prefrontal-Amygdala Outputs. Trends Neurosci 2017; 40:640-642. [PMID: 28988060 DOI: 10.1016/j.tins.2017.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 09/17/2017] [Indexed: 11/22/2022]
Abstract
Inhibitory interneurons comprise a diverse subpopulation of cells that are critical to circuit function. How distinct inhibitory microcircuits control long-range projections remains poorly understood. A recent study by Lu and colleagues uncovered a unidirectional microcircuit of prefrontal chandelier cells that preferentially innervate and suppress long-range amygdala-projecting pyramidal cells.
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25
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Lu J, Tucciarone J, Padilla-Coreano N, He M, Gordon JA, Huang ZJ. Selective inhibitory control of pyramidal neuron ensembles and cortical subnetworks by chandelier cells. Nat Neurosci 2017; 20:1377-1383. [PMID: 28825718 PMCID: PMC5614838 DOI: 10.1038/nn.4624] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 07/17/2017] [Indexed: 12/12/2022]
Abstract
The neocortex comprises multiple information processing streams mediated by subsets of glutamatergic pyramidal cells (PCs) that receive diverse inputs and project to distinct targets. How GABAergic interneurons regulate the segregation and communication among intermingled PC subsets that contribute to separate brain networks remains unclear. Here we demonstrate that a subset of GABAergic chandelier cells (ChCs) in the prelimbic cortex, which innervate PCs at spike initiation site, selectively control PCs projecting to the basolateral amygdala (BLAPC) compared to those projecting to contralateral cortex (CCPC). These ChCs in turn receive preferential input from local and contralateral CCPCs as opposed to BLAPCs and BLA neurons (the prelimbic cortex-BLA network). Accordingly, optogenetic activation of ChCs rapidly suppresses BLAPCs and BLA activity in freely behaving mice. Thus, the exquisite connectivity of ChCs not only mediates directional inhibition between local PC ensembles but may also shape communication hierarchies between global networks.
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Affiliation(s)
- Jiangteng Lu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Jason Tucciarone
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Program in Neuroscience and Medical Scientist Training Program, Stony Brook University, New York 11790, USA
| | - Nancy Padilla-Coreano
- Departments of Neuroscience and Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Miao He
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Joshua A. Gordon
- Departments of Neuroscience and Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Z. Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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26
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Selective inhibitory control of pyramidal neuron ensembles and cortical subnetworks by chandelier cells. Nat Neurosci 2017. [PMID: 28825718 DOI: 10.1038/nn.4624.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The neocortex comprises multiple information processing streams mediated by subsets of glutamatergic pyramidal cells (PCs) that receive diverse inputs and project to distinct targets. How GABAergic interneurons regulate the segregation and communication among intermingled PC subsets that contribute to separate brain networks remains unclear. Here we demonstrate that a subset of GABAergic chandelier cells (ChCs) in the prelimbic cortex, which innervate PCs at spike initiation site, selectively control PCs projecting to the basolateral amygdala (BLAPC) compared to those projecting to contralateral cortex (CCPC). These ChCs in turn receive preferential input from local and contralateral CCPCs as opposed to BLAPCs and BLA neurons (the prelimbic cortex-BLA network). Accordingly, optogenetic activation of ChCs rapidly suppresses BLAPCs and BLA activity in freely behaving mice. Thus, the exquisite connectivity of ChCs not only mediates directional inhibition between local PC ensembles but may also shape communication hierarchies between global networks.
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27
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Vascak M, Sun J, Baer M, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Evokes Pyramidal Neuron Axon Initial Segment Plasticity and Diffuse Presynaptic Inhibitory Terminal Loss. Front Cell Neurosci 2017. [PMID: 28634442 PMCID: PMC5459898 DOI: 10.3389/fncel.2017.00157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The axon initial segment (AIS) is the site of action potential (AP) initiation, thus a crucial regulator of neuronal activity. In excitatory pyramidal neurons, the high density of voltage-gated sodium channels (NaV1.6) at the distal AIS regulates AP initiation. A surrogate AIS marker, ankyrin-G (ankG) is a structural protein regulating neuronal functional via clustering voltage-gated ion channels. In neuronal circuits, changes in presynaptic input can alter postsynaptic output via AIS structural-functional plasticity. Recently, we showed experimental mild traumatic brain injury (mTBI) evokes neocortical circuit disruption via diffuse axonal injury (DAI) of excitatory and inhibitory neuronal systems. A key finding was that mTBI-induced neocortical electrophysiological changes involved non-DAI/ intact excitatory pyramidal neurons consistent with AIS-specific alterations. In the current study we employed Thy1-yellow fluorescent protein (YFP)-H mice to test if mTBI induces AIS structural and/or functional plasticity within intact pyramidal neurons 2 days after mTBI. We used confocal microscopy to assess intact YFP+ pyramidal neurons in layer 5 of primary somatosensory barrel field (S1BF), whose axons were continuous from the soma of origin to the subcortical white matter (SCWM). YFP+ axonal traces were superimposed on ankG and NaV1.6 immunofluorescent profiles to determine AIS position and length. We found that while mTBI had no effect on ankG start position, the length significantly decreased from the distal end, consistent with the site of AP initiation at the AIS. However, NaV1.6 structure did not change after mTBI, suggesting uncoupling from ankG. Parallel quantitative analysis of presynaptic inhibitory terminals along the postsynaptic perisomatic domain of these same intact YFP+ excitatory pyramidal neurons revealed a significant decrease in GABAergic bouton density. Also within this non-DAI population, patch-clamp recordings of intact YFP+ pyramidal neurons showed AP acceleration decreased 2 days post-mTBI, consistent with AIS functional plasticity. Simulations of realistic pyramidal neuron computational models using experimentally determined AIS lengths showed a subtle decrease is NaV1.6 density is sufficient to attenuate AP acceleration. Collectively, these findings highlight the complexity of mTBI-induced neocortical circuit disruption, involving changes in extrinsic/presynaptic inhibitory perisomatic input interfaced with intrinsic/postsynaptic intact excitatory neuron AIS output.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
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28
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Neocortical Chandelier Cells Developmentally Shape Axonal Arbors through Reorganization but Establish Subcellular Synapse Specificity without Refinement. eNeuro 2017; 4:eN-NWR-0057-17. [PMID: 28584877 PMCID: PMC5458751 DOI: 10.1523/eneuro.0057-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 11/21/2022] Open
Abstract
Diverse types of cortical interneurons (INs) mediate various kinds of inhibitory control mechanisms to balance and shape network activity. Distinct IN subtypes develop uniquely organized axonal arbors that innervate different subcellular compartments of excitatory principal neurons (PNs), which critically contribute to determining their output properties. However, it remains poorly understood how they establish this peculiar axonal organization and synaptic connectivity during development. Here, taking advantage of genetic labeling of IN progenitors, we examined developmental processes of axonal arbors and synaptic connections formed by murine chandelier cells (ChCs), which innervate axon initial segments (AISs) of PNs and thus powerfully regulate their spike generation. Our quantitative analysis by light microscopy revealed that ChCs overgrow and subsequently refine axonal branches as well as varicosities. Interestingly, we found that although a significant number of axonal varicosities are formed off AISs in addition to on AISs, presynaptic markers are predominantly colocalized with those on AISs throughout development. Immunoelectron microscopic (IEM) analysis also demonstrated that only varicosities apposed to AISs contain presynaptic profiles. These results suggest that subcellular synapse specificity of ChCs is genetically predetermined while axonal geometry is shaped through remodeling. Molecular cues localized at AISs may regulate target recognition and synapse formation by ChCs.
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29
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Hashemi E, Ariza J, Rogers H, Noctor SC, Martínez-Cerdeño V. The Number of Parvalbumin-Expressing Interneurons Is Decreased in the Prefrontal Cortex in Autism. Cereb Cortex 2017; 27:1931-1943. [PMID: 26922658 PMCID: PMC6074948 DOI: 10.1093/cercor/bhw021] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The cognitive phenotype of autism has been correlated with an altered balance of excitation to inhibition in the cerebral cortex, which could result from a change in the number, function, or morphology of GABA-expressing interneurons. The number of GABAergic interneuron subtypes has not been quantified in the autistic cerebral cortex. We classified interneurons into 3 subpopulations based on expression of the calcium-binding proteins parvalbumin, calbindin, or calretinin. We quantified the number of each interneuron subtype in postmortem neocortical tissue from 11 autistic cases and 10 control cases. Prefrontal Brodmann Areas (BA) BA46, BA47, and BA9 in autism and age-matched controls were analyzed by blinded researchers. We show that the number of parvalbumin+ interneurons in these 3 cortical areas-BA46, BA47, and BA9-is significantly reduced in autism compared with controls. The number of calbindin+ and calretinin+ interneurons did not differ in the cortical areas examined. Parvalbumin+ interneurons are fast-spiking cells that synchronize the activity of pyramidal cells through perisomatic and axo-axonic inhibition. The reduced number of parvalbumin+ interneurons could disrupt the balance of excitation/inhibition and alter gamma wave oscillations in the cerebral cortex of autistic subjects. These data will allow development of novel treatments specifically targeting parvalbumin interneurons.
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Affiliation(s)
- Ezzat Hashemi
- Department of Pathology and Laboratory Medicine
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA
| | - Jeanelle Ariza
- Department of Pathology and Laboratory Medicine
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA
| | - Haille Rogers
- Department of Pathology and Laboratory Medicine
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA
| | - Stephen C. Noctor
- Department of Psychiatry and Behavioral Sciences, UC Davis, Sacramento, CA, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
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30
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Saha R, Knapp S, Chakraborty D, Horovitz O, Albrecht A, Kriebel M, Kaphzan H, Ehrlich I, Volkmer H, Richter-Levin G. GABAergic Synapses at the Axon Initial Segment of Basolateral Amygdala Projection Neurons Modulate Fear Extinction. Neuropsychopharmacology 2017; 42:473-484. [PMID: 27634356 PMCID: PMC5399240 DOI: 10.1038/npp.2016.205] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 11/09/2022]
Abstract
Inhibitory synaptic transmission in the amygdala has a pivotal role in fear learning and its extinction. However, the local circuits formed by GABAergic inhibitory interneurons within the amygdala and their detailed function in shaping these behaviors are not well understood. Here we used lentiviral-mediated knockdown of the cell adhesion molecule neurofascin in the basolateral amygdala (BLA) to specifically remove inhibitory synapses at the axon initial segment (AIS) of BLA projection neurons. Quantitative analysis of GABAergic synapse markers and measurement of miniature inhibitory postsynaptic currents in BLA projection neurons after neurofascin knockdown ex vivo confirmed the loss of GABAergic input. We then studied the impact of this manipulation on anxiety-like behavior and auditory cued fear conditioning and its extinction as BLA related behavioral paradigms, as well as on long-term potentiation (LTP) in the ventral subiculum-BLA pathway in vivo. BLA knockdown of neurofascin impaired ventral subiculum-BLA-LTP. While this manipulation did not affect anxiety-like behavior and fear memory acquisition and consolidation, it specifically impaired extinction. Our findings indicate that modification of inhibitory synapses at the AIS of BLA projection neurons is sufficient to selectively impair extinction behavior. A better understanding of the role of distinct GABAergic synapses may provide novel and more specific targets for therapeutic interventions in extinction-based therapies.
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Affiliation(s)
- Rinki Saha
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Stephanie Knapp
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany,Graduate School for Neural and Behavioral Science, University of Tübingen, Tübingen, Germany
| | | | - Omer Horovitz
- Department of Psychology, University of Haifa, Haifa, Israel
| | - Anne Albrecht
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel,The Institute for the Study of Affective Neuroscience, University of Haifa, Haifa, Israel
| | - Martin Kriebel
- NMI Natural and Medical Sciences Institute, University of Tübingen, Reutlingen, Germany
| | - Hanoch Kaphzan
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Hansjürgen Volkmer
- NMI Natural and Medical Sciences Institute, University of Tübingen, Reutlingen, Germany
| | - Gal Richter-Levin
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel,Department of Psychology, University of Haifa, Haifa, Israel,The Institute for the Study of Affective Neuroscience, University of Haifa, Haifa, Israel,Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Avenue 199, Haifa 31905, Israel, Tel: +972 48240962, Fax: +972 48288578, E-mail:
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31
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He M, Tucciarone J, Lee S, Nigro MJ, Kim Y, Levine JM, Kelly SM, Krugikov I, Wu P, Chen Y, Gong L, Hou Y, Osten P, Rudy B, Huang ZJ. Strategies and Tools for Combinatorial Targeting of GABAergic Neurons in Mouse Cerebral Cortex. Neuron 2016; 91:1228-1243. [PMID: 27618674 PMCID: PMC5223593 DOI: 10.1016/j.neuron.2016.08.021] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 06/30/2016] [Accepted: 08/06/2016] [Indexed: 11/23/2022]
Abstract
Systematic genetic access to GABAergic cell types will facilitate studying the function and development of inhibitory circuitry. However, single gene-driven recombinase lines mark relatively broad and heterogeneous cell populations. Although intersectional approaches improve precision, it remains unclear whether they can capture cell types defined by multiple features. Here we demonstrate that combinatorial genetic and viral approaches target restricted GABAergic subpopulations and cell types characterized by distinct laminar location, morphology, axonal projection, and electrophysiological properties. Intersectional embryonic transcription factor drivers allow finer fate mapping of progenitor pools that give rise to distinct GABAergic populations, including laminar cohorts. Conversion of progenitor fate restriction signals to constitutive recombinase expression enables viral targeting of cell types based on their lineage and birth time. Properly designed intersection, subtraction, conversion, and multi-color reporters enhance the precision and versatility of drivers and viral vectors. These strategies and tools will facilitate studying GABAergic neurons throughout the mouse brain.
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Affiliation(s)
- Miao He
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Jason Tucciarone
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Program in Neuroscience and Medical Scientist Training Program, Stony Brook University, Stony Brook, NY 11790, USA
| | - SooHyun Lee
- New York University Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Maximiliano José Nigro
- New York University Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Yongsoo Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Jesse Maurica Levine
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Program in Neuroscience and Medical Scientist Training Program, Stony Brook University, Stony Brook, NY 11790, USA
| | - Sean Michael Kelly
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Program in Neuroscience and Medical Scientist Training Program, Stony Brook University, Stony Brook, NY 11790, USA
| | - Illya Krugikov
- New York University Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Priscilla Wu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Yang Chen
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Ling Gong
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Yongjie Hou
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Bernardo Rudy
- New York University Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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32
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Metzner C, Schweikard A, Zurowski B. Multifactorial Modeling of Impairment of Evoked Gamma Range Oscillations in Schizophrenia. Front Comput Neurosci 2016; 10:89. [PMID: 27616989 PMCID: PMC4999438 DOI: 10.3389/fncom.2016.00089] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/10/2016] [Indexed: 12/26/2022] Open
Abstract
Despite a significant increase in efforts to identify biomarkers and endophenotypic measures of psychiatric illnesses, only a very limited amount of computational models of these markers and measures has been implemented so far. Moreover, existing computational models dealing with biomarkers typically only examine one possible mechanism in isolation, disregarding the possibility that other combinations of model parameters might produce the same network behavior (what has been termed "multifactoriality"). In this study we describe a step toward a computational instantiation of an endophenotypic finding for schizophrenia, namely the impairment of evoked auditory gamma and beta oscillations in schizophrenia. We explore the multifactorial nature of this impairment using an established model of primary auditory cortex, by performing an extensive search of the parameter space. We find that single network parameters contain only little information about whether the network will show impaired gamma entrainment and that different regions in the parameter space yield similar network level oscillation abnormalities. These regions in the parameter space, however, show strong differences in the underlying network dynamics. To sum up, we present a first step toward an in silico instantiation of an important biomarker of schizophrenia, which has great potential for the identification and study of disease mechanisms and for understanding of existing treatments and development of novel ones.
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Affiliation(s)
- Christoph Metzner
- Biocomputation Research Group, University of HertfordshireHatfield, UK
| | - Achim Schweikard
- Institute for Robotics and Cognitive Systems, University of LuebeckLuebeck, Germany
| | - Bartosz Zurowski
- Centre for Integrative Psychiatry, University of LuebeckLuebeck, Germany
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33
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Cong D, Zhu W, Kuo JS, Hu S, Sun D. Ion transporters in brain tumors. Curr Med Chem 2016; 22:1171-81. [PMID: 25620102 DOI: 10.2174/0929867322666150114151946] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/05/2015] [Accepted: 01/08/2015] [Indexed: 11/22/2022]
Abstract
Ion transporters are important in regulation of ionic homeostasis, cell volume, and cellular signal transduction under physiological conditions. They have recently emerged as important players in cancer progression. In this review, we discussed two important ion transporter proteins, sodium-potassium-chloride cotransporter isoform 1 (NKCC-1) and sodium-hydrogen exchanger isoform 1 (NHE-1) in Glioblastoma multiforme (GBM) and other malignant tumors. NKCC-1 is a Na(+)- dependent Cl(-) transporter that mediates the movement of Na(+), K(+), and Cl(-) ions across the plasma membrane and maintains cell volume and intracellular K(+) and Cl(-) homeostasis. NHE-1 is a ubiquitously expressed cell membrane protein which regulates intracellular pH (pH(i)) and extracellular pH (pH(e)) homeostasis and cell volume. Here, we summarized recent pre-clinical experimental studies on NKCC-1 and NHE-1 in GBM and other malignant tumors, such as breast cancer, hepatocellular carcinoma, and lung cancer cells. These studies illustrated that pharmacological inhibition or down-regulation of these ion transporter proteins reduces proliferation, increases apoptosis, and suppresses migration and invasion of cancer cells. These new findings reveal the potentials of these ion transporters as new targets for cancer diagnosis and/or treatment.
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Affiliation(s)
| | | | | | | | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School, S-598 South Biomedical Science Tower (BST), 3500 Terrace St., Pittsburgh, PA 15213, USA.
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34
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Naka A, Adesnik H. Inhibitory Circuits in Cortical Layer 5. Front Neural Circuits 2016; 10:35. [PMID: 27199675 PMCID: PMC4859073 DOI: 10.3389/fncir.2016.00035] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/18/2016] [Indexed: 01/19/2023] Open
Abstract
Inhibitory neurons play a fundamental role in cortical computation and behavior. Recent technological advances, such as two photon imaging, targeted in vivo recording, and molecular profiling, have improved our understanding of the function and diversity of cortical interneurons, but for technical reasons most work has been directed towards inhibitory neurons in the superficial cortical layers. Here we review current knowledge specifically on layer 5 (L5) inhibitory microcircuits, which play a critical role in controlling cortical output. We focus on recent work from the well-studied rodent barrel cortex, but also draw on evidence from studies in primary visual cortex and other cortical areas. The diversity of both deep inhibitory neurons and their pyramidal cell targets make this a challenging but essential area of study in cortical computation and sensory processing.
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Affiliation(s)
- Alexander Naka
- The Helen Wills Neuroscience Institute, University of California Berkeley Berkeley, CA, USA
| | - Hillel Adesnik
- The Helen Wills Neuroscience Institute, University of California BerkeleyBerkeley, CA, USA; Department of Molecular and Cell Biology, University of California BerkeleyBerkeley, CA, USA
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Wang Y, Zhang P, Wyskiel DR. Chandelier Cells in Functional and Dysfunctional Neural Circuits. Front Neural Circuits 2016; 10:33. [PMID: 27199673 PMCID: PMC4854894 DOI: 10.3389/fncir.2016.00033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/08/2016] [Indexed: 01/08/2023] Open
Abstract
Chandelier cells (ChCs; also called axo-axonic cells) are a specialized GABAergic interneuron subtype that selectively innervates pyramidal neurons at the axon initial segment (AIS), the site of action potential generation. ChC connectivity allows for powerful yet precise modulation of large populations of pyramidal cells, suggesting ChCs have a critical role in brain functions. Dysfunctions in ChC connectivity are associated with brain disorders such as epilepsy and schizophrenia; however, whether this is causative, contributory or compensatory is not known. A likely stumbling block toward mechanistic discoveries and uncovering potential therapeutic targets is the apparent lack of rudimentary understanding of ChCs. For example, whether cortical ChCs are inhibitory or excitatory remains unresolved, and thus whether altered ChC activity results in altered inhibition or excitation is not clear. Recent studies have shed some light onto this excitation-inhibition controversy. In addition, new findings have identified preferential cell-type connectivities established by cortical ChCs, greatly expanding our understanding of the role of ChCs in the cortical microcircuit. Here we aim to bring more attention to ChC connectivity to better understand its role in neural circuits, address whether ChCs are inhibitory or excitatory in light of recent findings and discuss ChC dysfunctions in brain disorders.
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Affiliation(s)
- Yiqing Wang
- Department of Pharmacology, University of VirginiaCharlottesville, VA, USA; Department of Chemistry, University of VirginiaCharlottesville, VA, USA
| | - Peng Zhang
- Department of Pharmacology, University of Virginia Charlottesville, VA, USA
| | - Daniel R Wyskiel
- Department of Pharmacology, University of Virginia Charlottesville, VA, USA
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Brown JA, Ramikie TS, Schmidt MJ, Báldi R, Garbett K, Everheart MG, Warren LE, Gellért L, Horváth S, Patel S, Mirnics K. Inhibition of parvalbumin-expressing interneurons results in complex behavioral changes. Mol Psychiatry 2015; 20:1499-507. [PMID: 25623945 PMCID: PMC4516717 DOI: 10.1038/mp.2014.192] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/06/2014] [Accepted: 12/08/2014] [Indexed: 12/20/2022]
Abstract
Reduced expression of the Gad1 gene-encoded 67-kDa protein isoform of glutamic acid decarboxylase (GAD67) is a hallmark of schizophrenia. GAD67 downregulation occurs in multiple interneuronal sub-populations, including the parvalbumin-positive (PVALB+) cells. To investigate the role of the PV-positive GABAergic interneurons in behavioral and molecular processes, we knocked down the Gad1 transcript using a microRNA engineered to target specifically Gad1 mRNA under the control of Pvalb bacterial artificial chromosome. Verification of construct expression was performed by immunohistochemistry. Follow-up electrophysiological studies revealed a significant reduction in γ-aminobutyric acid (GABA) release probability without alterations in postsynaptic membrane properties or changes in glutamatergic release probability in the prefrontal cortex pyramidal neurons. Behavioral characterization of our transgenic (Tg) mice uncovered that the Pvalb/Gad1 Tg mice have pronounced sensorimotor gating deficits, increased novelty-seeking and reduced fear extinction. Furthermore, NMDA (N-methyl-d-aspartate) receptor antagonism by ketamine had an opposing dose-dependent effect, suggesting that the differential dosage of ketamine might have divergent effects on behavioral processes. All behavioral studies were validated using a second cohort of animals. Our results suggest that reduction of GABAergic transmission from PVALB+ interneurons primarily impacts behavioral domains related to fear and novelty seeking and that these alterations might be related to the behavioral phenotype observed in schizophrenia.
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Affiliation(s)
- Jacquelyn A. Brown
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
| | - Teniel S. Ramikie
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Martin J. Schmidt
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Rita Báldi
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA
| | - Krassimira Garbett
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA
| | | | - Lambert E. Warren
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
| | - Levente Gellért
- Department of Psychiatry, University of Szeged, 6725 Szeged, Hungary
| | - Szatmár Horváth
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Department of Psychiatry, University of Szeged, 6725 Szeged, Hungary
| | - Sachin Patel
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Károly Mirnics
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA,Department of Psychiatry, University of Szeged, 6725 Szeged, Hungary,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA,Correspondence: Karoly Mirnics, Department of Psychiatry, Vanderbilt University, 8130A MRB III, 465 21st Avenue South, Nashville TN 37232, USA, , Office phone: 615-936-1074, www.mirnicslab.org
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37
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Evans MD, Dumitrescu AS, Kruijssen DLH, Taylor SE, Grubb MS. Rapid Modulation of Axon Initial Segment Length Influences Repetitive Spike Firing. Cell Rep 2015; 13:1233-1245. [PMID: 26526995 PMCID: PMC4646840 DOI: 10.1016/j.celrep.2015.09.066] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/10/2015] [Accepted: 09/22/2015] [Indexed: 12/31/2022] Open
Abstract
Neurons implement a variety of plasticity mechanisms to alter their function over timescales ranging from seconds to days. One powerful means of controlling excitability is to directly modulate the site of spike initiation, the axon initial segment (AIS). However, all plastic structural AIS changes reported thus far have been slow, involving days of neuronal activity perturbation. Here, we show that AIS plasticity can be induced much more rapidly. Just 3 hr of elevated activity significantly shortened the AIS of dentate granule cells in a calcineurin-dependent manner. The functional effects of rapid AIS shortening were offset by dephosphorylation of voltage-gated sodium channels, another calcineurin-dependent mechanism. However, pharmacological separation of these phenomena revealed a significant relationship between AIS length and repetitive firing. The AIS can therefore undergo a rapid form of structural change over timescales that enable interactions with other forms of activity-dependent plasticity in the dynamic control of neuronal excitability. Structural plasticity at the axon initial segment can occur within hours Ankyrin-G and sodium channel distributions shorten after 3 hr of elevated activity Rapid plasticity depends on calcineurin signaling opposed by CDK5 All else being equal, AIS shortening correlates with lowered neuronal excitability
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Affiliation(s)
- Mark D Evans
- MRC Centre for Developmental Neurobiology, King's College London, 4(th) Floor, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Adna S Dumitrescu
- MRC Centre for Developmental Neurobiology, King's College London, 4(th) Floor, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Dennis L H Kruijssen
- MRC Centre for Developmental Neurobiology, King's College London, 4(th) Floor, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Samuel E Taylor
- MRC Centre for Developmental Neurobiology, King's College London, 4(th) Floor, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Matthew S Grubb
- MRC Centre for Developmental Neurobiology, King's College London, 4(th) Floor, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
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Activity-dependent mismatch between axo-axonic synapses and the axon initial segment controls neuronal output. Proc Natl Acad Sci U S A 2015. [PMID: 26195803 DOI: 10.1073/pnas.1502902112] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The axon initial segment (AIS) is a structure at the start of the axon with a high density of sodium and potassium channels that defines the site of action potential generation. It has recently been shown that this structure is plastic and can change its position along the axon, as well as its length, in a homeostatic manner. Chronic activity-deprivation paradigms in a chick auditory nucleus lead to a lengthening of the AIS and an increase in neuronal excitability. On the other hand, a long-term increase in activity in dissociated rat hippocampal neurons results in an outward movement of the AIS and a decrease in the cell's excitability. Here, we investigated whether the AIS is capable of undergoing structural plasticity in rat hippocampal organotypic slices, which retain the diversity of neuronal cell types present at postnatal ages, including chandelier cells. These interneurons exclusively target the AIS of pyramidal neurons and form rows of presynaptic boutons along them. Stimulating individual CA1 pyramidal neurons that express channelrhodopsin-2 for 48 h leads to an outward shift of the AIS. Intriguingly, both the pre- and postsynaptic components of the axo-axonic synapses did not change position after AIS relocation. We used computational modeling to explore the functional consequences of this partial mismatch and found that it allows the GABAergic synapses to strongly oppose action potential generation, and thus downregulate pyramidal cell excitability. We propose that this spatial arrangement is the optimal configuration for a homeostatic response to long-term stimulation.
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Arteaga G, Buritica E, Escobar MI, Pimienta H. Human prefrontal layer II interneurons in areas 46, 10 and 24. Colomb Med (Cali) 2015; 46:19-25. [PMID: 26019381 PMCID: PMC4437283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/10/2014] [Accepted: 02/02/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Prefrontal cortex (PFC) represents the highest level of integration and control of psychic and behavioral states. Several dysfunctions such as autism, hyperactivity disorders, depression, and schizophrenia have been related with alterations in the prefrontal cortex (PFC). Among the cortical layers of the PFC, layer II shows a particular vertical pattern of organization, the highest cell density and the biggest non-pyramidal/pyramidal neuronal ratio. We currently characterized the layer II cytoarchitecture in human areas 10, 24, and 46. OBJECTIVE We focused particularly on the inhibitory neurons taking into account that these cells are involved in sustained firing (SF) after stimuli disappearance. METHODS Postmortem samples from five subjects who died by causes different to central nervous system diseases were studied. Immunohistochemistry for the neuronal markers, NeuN, parvalbumin (PV), calbindin (CB), and calretinin (CR) were used. NeuN targeted the total neuronal population while the rest of the markers specifically the interneurons. RESULTS Cell density and soma size were statically different between areas 10, 46, 24 when using NeuN. Layer II of area 46 showed the highest cell density. Regarding interneurons, PV+-cells of area 46 showed the highest density and size, in accordance to the proposal of a dual origin of the cerebral cortex. Interhemispheric asymmetries were not identified between homologue areas. CONCLUSION First, our findings suggest that layer II of area 46 exhibits the most powerful inhibitory system compared to the other prefrontal areas analyzed. This feature is not only characteristic of the PFC but also supports a particular role of layer II of area 46 in SF. Additionally, known functional asymmetries between hemispheres might not be supported by morphological asymmetries.
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Affiliation(s)
| | | | | | - Hernan Pimienta
- Centro de Estudios Cerebrales, Facultad de Salud, Universidad del Valle, Cali, Colombia
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40
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King AN, Manning CF, Trimmer JS. A unique ion channel clustering domain on the axon initial segment of mammalian neurons. J Comp Neurol 2015; 522:2594-608. [PMID: 24477962 DOI: 10.1002/cne.23551] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 01/11/2023]
Abstract
The axon initial segment (AIS) plays a key role in initiation of action potentials and neuronal output. The plasma membrane of the AIS contains high densities of voltage-gated ion channels required for these electrical events, and much recent work has focused on defining the mechanisms for generating and maintaining this unique neuronal plasma membrane domain. The Kv2.1 voltage-gated potassium channel is abundantly present in large clusters on the soma and proximal dendrites of mammalian brain neurons. Kv2.1 is also a component of the ion channel repertoire at the AIS. Here we show that Kv2.1 clusters on the AIS of brain neurons across diverse mammalian species including humans define a noncanonical ion channel clustering domain deficient in Ankyrin-G. The sites of Kv2.1 clustering on the AIS are sites where cisternal organelles, specialized intracellular calcium release membranes, come into close apposition with the plasma membrane, and are also sites of clustering of γ-aminobutyric acid (GABA)ergic synapses. Using an antibody specific for a single Kv2.1 phosphorylation site, we find that the phosphorylation state differs between Kv2.1 clusters on the proximal and distal portions of the AIS. Together, these studies show that the sites of Kv2.1 clustering on the AIS represent specialized domains containing components of diverse neuronal signaling pathways that may contribute to local regulation of Kv2.1 function and AIS membrane excitability.
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Affiliation(s)
- Anna N King
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, 95616
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41
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Schmidt MJ, Mirnics K. Neurodevelopment, GABA system dysfunction, and schizophrenia. Neuropsychopharmacology 2015; 40:190-206. [PMID: 24759129 PMCID: PMC4262918 DOI: 10.1038/npp.2014.95] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/03/2014] [Accepted: 04/11/2014] [Indexed: 02/07/2023]
Abstract
The origins of schizophrenia have eluded clinicians and researchers since Kraepelin and Bleuler began documenting their findings. However, large clinical research efforts in recent decades have identified numerous genetic and environmental risk factors for schizophrenia. The combined data strongly support the neurodevelopmental hypothesis of schizophrenia and underscore the importance of the common converging effects of diverse insults. In this review, we discuss the evidence that genetic and environmental risk factors that predispose to schizophrenia disrupt the development and normal functioning of the GABAergic system.
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Affiliation(s)
- Martin J Schmidt
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
| | - Karoly Mirnics
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN, USA
- Department of Psychiatry, University of Szeged, Szeged, Hungary
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42
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Varga C, Oijala M, Lish J, Szabo GG, Bezaire M, Marchionni I, Golshani P, Soltesz I. Functional fission of parvalbumin interneuron classes during fast network events. eLife 2014; 3. [PMID: 25375253 PMCID: PMC4270094 DOI: 10.7554/elife.04006] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/06/2014] [Indexed: 11/22/2022] Open
Abstract
Fast spiking, parvalbumin (PV) expressing hippocampal interneurons are classified into basket, axo-axonic (chandelier), and bistratified cells. These cell classes play key roles in regulating local circuit operations and rhythmogenesis by releasing GABA in precise temporal patterns onto distinct domains of principal cells. In this study, we show that each of the three major PV cell classes further splits into functionally distinct sub-classes during fast network events in vivo. During the slower (<10 Hz) theta oscillations, each cell class exhibited its own characteristic, relatively uniform firing behavior. However, during faster (>90 Hz) oscillations, within-class differences in PV interneuron discharges emerged, which segregated along specific features of dendritic structure or somatic location. Functional divergence of PV sub-classes during fast but not slow network oscillations effectively doubles the repertoire of spatio-temporal patterns of GABA release available for rapid circuit operations. DOI:http://dx.doi.org/10.7554/eLife.04006.001 The brain continuously processes information from outside and inside the body to cope with the challenges of everyday life. As the brain carries out these processes, networks of neurons produce patterns of electrical activities called oscillations. Fast-spiking PV cells are neurons that orchestrate the precise timing of these oscillations in a region of the brain called the hippocampus, which is important for the formation of memories. PV cells perform this role by releasing a chemical called GABA that suppresses electrical activity. The hippocampus contains three distinct sub-classes of fast-spiking PV cells, but it is not clear how these different sub-classes collaborate to control the network oscillations in the hippocampus. Varga et al. have now explored this question by recording the electrical activity of PV cells in mice, while they were resting and also while they were running. PV cells are involved in both fast and slow network oscillations. As had been found in previous experiments, Varga et al. found that the three different sub-classes of PV cells behaved similarly during slow network oscillations. During fast oscillations, however, the neurons within each sub-class displayed two distinct types of behavior, depending on their shape and location. PV cells release GABA in patterns that depend on both space and time: the work of Varga et al. shows that the repertoire of patterns that can be employed by PV cells is about twice as big as was previously thought. Future studies are needed to explore the influence of this behavior on memory. DOI:http://dx.doi.org/10.7554/eLife.04006.002
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Affiliation(s)
- Csaba Varga
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Mikko Oijala
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Jonathan Lish
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Gergely G Szabo
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Marianne Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Marchionni
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Ivan Soltesz
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
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Economo MN, Martínez JJ, White JA. Membrane potential-dependent integration of synaptic inputs in entorhinal stellate neurons. Hippocampus 2014; 24:1493-505. [PMID: 25044927 DOI: 10.1002/hipo.22329] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2014] [Indexed: 11/06/2022]
Abstract
Stellate cells (SCs) of the medial entorhinal cortex exhibit robust spontaneous membrane-potential oscillations (MPOs) in the theta (4-12 Hz) frequency band as well as theta-frequency resonance in their membrane impedance spectra. Past experimental and modeling work suggests that these features may contribute to the phase-locking of SCs to the entorhinal theta rhythm and may be important for forming the hexagonally tiled grid cell place fields exhibited by these neurons in vivo. Among the major biophysical mechanisms contributing to MPOs is a population of persistent (non-inactivating or slowly inactivating) sodium channels. The resulting persistent sodium conductance (GNaP ) gives rise to an apparent increase in input resistance as the cell approaches threshold. In this study, we used dynamic clamp to test the hypothesis that this increased input resistance gives rise to voltage-dependent, and thus MPO phase-dependent, changes in the amplitude of excitatory and inhibitory post-synaptic potential (PSP) amplitudes. We find that PSP amplitude depends on membrane potential, exhibiting a 5-10% increase in amplitude per mV depolarization. The effect is larger than-and sums quasi-linearly with-the effect of the synaptic driving force, V - Esyn . Given that input-driven MPOs 10 mV in amplitude are commonly observed in MEC stellate cells in vivo, this voltage- and phase-dependent synaptic gain is large enough to modulate PSP amplitude by over 50% during theta-frequency MPOs. Phase-dependent synaptic gain may therefore impact the phase locking and phase precession of grid cells in vivo to ongoing network oscillations. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael N Economo
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts; Department of Bioengineering, Brain Institute, University of Utah, Salt Lake City, Utah
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44
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Tyson JA, Anderson SA. GABAergic interneuron transplants to study development and treat disease. Trends Neurosci 2014; 37:169-77. [PMID: 24508416 PMCID: PMC4396846 DOI: 10.1016/j.tins.2014.01.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/06/2014] [Accepted: 01/06/2014] [Indexed: 01/06/2023]
Abstract
Advances in stem cell technology have engendered keen interest in cell-based therapies for neurological disorders. Postnatal engraftments of most neuronal precursors result in little cellular migration, a crucial prerequisite for transplants to integrate within the host circuitry. This may occur because most neurons migrate along substrates, such as radial glial processes, that are not abundant in adults. However, cortical GABAergic interneurons migrate tangentially from the subcortical forebrain into the cerebral cortex. Accordingly, transplants of cortical interneuron precursors migrate extensively after engraftment into a variety of CNS tissues, where they can become synaptically connected with host circuitry. We review how this remarkable ability to integrate post-transplant is being applied to the development of cell-based therapies for a variety of CNS disorders.
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Affiliation(s)
- Jennifer A Tyson
- Department of Psychiatry, Weill Medical College of Cornell University, New York, NY 10021, USA; Department of Psychiatry, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Stewart A Anderson
- Department of Psychiatry, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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45
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Inan M, Anderson SA. The chandelier cell, form and function. Curr Opin Neurobiol 2014; 26:142-8. [PMID: 24556285 DOI: 10.1016/j.conb.2014.01.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/20/2014] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
Abstract
Among γ-aminobutyric acid (GABA) interneurons, the chandelier cell (ChC) has captured the interest of neuroscientists for a very long time as a subtype not described by Ramon y Cajal. ChCs feature an axonal arborization that selectively innervates the axon initial segments of pyramidal cells. Recent studies involving transgenic mice have identified intriguing features of ChCs, including a remarkably specific spatial and temporal origins, their capacity to have either excitatory or inhibitory influences on pyramidal neurons, and their synaptic alterations in schizophrenia. This review explores these and other developmental and functional aspects of this fascinating cortical neuronal subtype.
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Affiliation(s)
- Melis Inan
- Weill Cornell Medical College, New York, NY, United States
| | - Stewart A Anderson
- Children's Hospital of Philadelphia/University of Pennsylvania, School of Medicine, Philadelphia, PA, United States.
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46
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Tai Y, Janas JA, Wang CL, Van Aelst L. Regulation of chandelier cell cartridge and bouton development via DOCK7-mediated ErbB4 activation. Cell Rep 2014; 6:254-63. [PMID: 24440718 DOI: 10.1016/j.celrep.2013.12.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/01/2013] [Accepted: 12/20/2013] [Indexed: 01/04/2023] Open
Abstract
Chandelier cells (ChCs), typified by their unique axonal morphology, are the most distinct interneurons present in cortical circuits. Via their distinctive axonal terminals, called cartridges, these cells selectively target the axon initial segment of pyramidal cells and control action potential initiation; however, the mechanisms that govern the characteristic ChC axonal structure have remained elusive. Here, by employing an in utero electroporation-based method that enables genetic labeling and manipulation of ChCs in vivo, we identify DOCK7, a member of the DOCK180 family, as a molecule essential for ChC cartridge and bouton development. Furthermore, we present evidence that DOCK7 functions as a cytoplasmic activator of the schizophrenia-associated ErbB4 receptor tyrosine kinase and that DOCK7 modulates ErbB4 activity to control ChC cartridge and bouton development. Thus, our findings define DOCK7 and ErbB4 as key components of a pathway that controls the morphological differentiation of ChCs, with implications for the pathogenesis of schizophrenia.
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Affiliation(s)
- Yilin Tai
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Justyna A Janas
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Chia-Lin Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Linda Van Aelst
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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47
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Westerholz S, de Lima AD, Voigt T. Thyroid hormone-dependent development of early cortical networks: temporal specificity and the contribution of trkB and mTOR pathways. Front Cell Neurosci 2013; 7:121. [PMID: 23964198 PMCID: PMC3734363 DOI: 10.3389/fncel.2013.00121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022] Open
Abstract
Early in neocortical network development, triiodothyronine (T3) promotes GABAergic neurons' population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons (non-GABA). A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first 2 weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical 2-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2), and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABA. The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB) or mammalian target of rapamycin (mTOR) pathways. T3-dependent increase in GABAergic neurons' soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.
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Affiliation(s)
- Sören Westerholz
- Institute of Physiology, Otto-von-Guericke University Magdeburg, Germany
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Löscher W, Puskarjov M, Kaila K. Cation-chloride cotransporters NKCC1 and KCC2 as potential targets for novel antiepileptic and antiepileptogenic treatments. Neuropharmacology 2013; 69:62-74. [PMID: 22705273 DOI: 10.1016/j.neuropharm.2012.05.045] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/22/2012] [Accepted: 05/28/2012] [Indexed: 12/31/2022]
Abstract
In cortical and hippocampal neurons, cation-chloride cotransporters (CCCs) control the reversal potential (EGABA) of GABAA receptor-mediated current and voltage responses and, consequently, they modulate the efficacy of GABAergic inhibition. Two members of the CCC family, KCC2 (the major neuron-specific K-Cl cotransporter; KCC isoform 2) and NKCC1 (the Na-K-2Cl cotransporter isoform 1 which is expressed in both neurons and glial cells) have attracted much interest in studies on GABAergic signaling under both normal and pathophysiological conditions, such as epilepsy. There is tentative evidence that loop diuretic compounds such as furosemide and bumetanide may have clinically relevant antiepileptic actions, especially when administered in combination with conventional GABA-mimetic drugs such as phenobarbital. Furosemide is a non-selective inhibitor of CCCs while at low concentrations bumetanide is selective for NKCCs. Search for novel antiepileptic drugs (AEDs) is highly motivated especially for the treatment of neonatal seizures which are often resistant to, or even aggravated by conventional AEDs. This review shows that the antiepileptic effects of loop diuretics described in the pertinent literature are based on widely heterogeneous mechanisms ranging from actions on both neuronal NKCC1 and KCC2 to modulation of the brain extracellular volume fraction. A promising strategy for the development of novel CCC-blocking AEDs is based on prodrugs that are activated following their passage across the blood-brain barrier. This article is part of the Special Issue entitled 'New Targets and Approaches to the Treatment of Epilepsy'.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany.
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Le Magueresse C, Monyer H. GABAergic interneurons shape the functional maturation of the cortex. Neuron 2013; 77:388-405. [PMID: 23395369 DOI: 10.1016/j.neuron.2013.01.011] [Citation(s) in RCA: 308] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
Abstract
From early embryonic development to adulthood, GABA release participates in the construction of the mammalian cerebral cortex. The maturation of GABAergic neurotransmission is a protracted process which takes place in discrete steps and results from the dynamic interaction between developmentally directed gene expression and brain activity. During the course of development, GABAergic interneurons contribute to key aspects of the functional maturation of the cortex in different ways, from exerting a trophic role to pacing immature neural networks. In this review, we provide an overview of the maturation of GABAergic neurotransmission and discuss the role of GABAergic interneurons in cortical wiring, plasticity, and network activity during pre- and postnatal development. We also discuss psychiatric diseases that may be considered at least in part developmental disorders of the GABAergic system.
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Affiliation(s)
- Corentin Le Magueresse
- Department of Clinical Neurobiology, Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
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Abstract
Chandelier (or axo-axonic) cells are a distinct group of GABAergic interneurons that innervate the axon initial segments of pyramidal cells and thus could have an important role controlling the activity of cortical circuits. To understand their connectivity, we labeled upper layers chandelier cells (ChCs) from mouse neocortex with a genetic strategy and studied how their axons contact local populations of pyramidal neurons, using immunohistochemical detection of axon initial segments. We studied ChCs located in the border of layers 1 and 2 from primary somatosensory cortex and found that practically all ChC axon terminals contact axon initial segments, with an average of three to five boutons per cartridge. By measuring the number of putative GABAergic synapses in initial segments, we estimate that each pyramidal neuron is innervated, on average, by four ChCs. Additionally, each individual ChC contacts 35-50% of pyramidal neurons within the areas traversed by its axonal arbor, with pockets of very high innervation density. Finally, ChCs have similar innervation patterns at different postnatal ages (P18-P90), with only relatively small lateral expansions of their arbor and increases in the total number of their cartridges during the developmental period analyzed. We conclude that ChCs innervate neighboring pyramidal neurons in a dense and overlapping manner, a connectivity pattern that could enable ChCs to exert a widespread influence on their local circuits.
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