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Cieri MB, Ramos AJ. Astrocytes, reactive astrogliosis, and glial scar formation in traumatic brain injury. Neural Regen Res 2025; 20:973-989. [PMID: 38989932 PMCID: PMC11438322 DOI: 10.4103/nrr.nrr-d-23-02091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 04/14/2024] [Indexed: 07/12/2024] Open
Abstract
Traumatic brain injury is a global health crisis, causing significant death and disability worldwide. Neuroinflammation that follows traumatic brain injury has serious consequences for neuronal survival and cognitive impairments, with astrocytes involved in this response. Following traumatic brain injury, astrocytes rapidly become reactive, and astrogliosis propagates from the injury core to distant brain regions. Homeostatic astroglial proteins are downregulated near the traumatic brain injury core, while pro-inflammatory astroglial genes are overexpressed. This altered gene expression is considered a pathological remodeling of astrocytes that produces serious consequences for neuronal survival and cognitive recovery. In addition, glial scar formed by reactive astrocytes is initially necessary to limit immune cell infiltration, but in the long term impedes axonal reconnection and functional recovery. Current therapeutic strategies for traumatic brain injury are focused on preventing acute complications. Statins, cannabinoids, progesterone, beta-blockers, and cerebrolysin demonstrate neuroprotective benefits but most of them have not been studied in the context of astrocytes. In this review, we discuss the cell signaling pathways activated in reactive astrocytes following traumatic brain injury and we discuss some of the potential new strategies aimed to modulate astroglial responses in traumatic brain injury, especially using cell-targeted strategies with miRNAs or lncRNA, viral vectors, and repurposed drugs.
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Affiliation(s)
- María Belén Cieri
- Laboratorio de Neuropatología Molecular, IBCN UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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2
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Waxman S, Schilpp H, Linton A, Jakobs TC, Sigal IA. Morphological comparison of astrocytes in the lamina cribrosa and glial lamina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.07.610493. [PMID: 39314351 PMCID: PMC11418941 DOI: 10.1101/2024.09.07.610493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Purpose Although the mechanisms underlying glaucomatous neurodegeneration are not yet well understood, cellular and small animal models suggest that LC astrocytes undergo early morphologic and functional changes, indicating their role as early responders to glaucomatous stress. These models, however, lack the LC found in larger animals and humans, leaving the in situ morphology of LC astrocytes and their role in glaucoma initiation underexplored. In this work, we aimed to characterize the morphology of LC astrocytes in situ and determine differences and similarities with astrocytes in the mouse glial lamina (GL), the analogous structure in a prominent glaucoma model. Methods Astrocytes in the LCs of twenty-two eyes from goats, sheep, and pigs were stochastically labeled via Multicolor DiOlistics and imaged in situ using confocal microscopy. 3D models of DiOlistically-labeled LC astrocytes and hGFAPpr-GFP mouse GL astrocytes were constructed to quantify morphological features related to astrocyte functions. LC and GL astrocyte cross-pore contacts, branching complexity, branch tortuosity, and cell and branch span were compared. Results LC astrocytes displayed distinct spatial relationships with collagen, greater branching complexity, and higher branch tortuosity compared to GL astrocytes. Despite substantial differences in their anatomical environments, LC and GL astrocytes had similar cell and branch spans. Conclusions Astrocyte morphology in the LC was characterized through Multicolor DiOlistic labeling. LC and GL astrocytes have both distinct and shared morphological features. Further research is needed to understand the potentially unique roles of LC astrocytes in glaucoma initiation and progression.
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Affiliation(s)
- Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh PA, USA
| | - Hannah Schilpp
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh PA, USA
| | - Ashley Linton
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh PA, USA
| | - Tatjana C. Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, Boston, MA, USA
| | - Ian A. Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh PA, USA
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3
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Delgado-García LM, Ojalvo-Sanz AC, Nakamura TKE, Martín-López E, Porcionatto M, Lopez-Mascaraque L. Dissecting reactive astrocyte responses: lineage tracing and morphology-based clustering. Biol Res 2024; 57:54. [PMID: 39143594 PMCID: PMC11323641 DOI: 10.1186/s40659-024-00532-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/29/2024] [Indexed: 08/16/2024] Open
Abstract
Brain damage triggers diverse cellular and molecular events, with astrocytes playing a crucial role in activating local neuroprotective and reparative signaling within damaged neuronal circuits. Here, we investigated reactive astrocytes using a multidimensional approach to categorize their responses into different subtypes based on morphology. This approach utilized the StarTrack lineage tracer, single-cell imaging reconstruction and multivariate data analysis. Our findings identified three profiles of reactive astrocyte responses, categorized by their effects on cell size- and shape- related morphological parameters: "moderate", "strong," and "very strong". We also examined the heterogeneity of astrocyte reactivity, focusing on spatial and clonal distribution. Our research revealed a notable enrichment of protoplasmic and fibrous astrocytes within the "strong" and "very strong" response subtypes. Overall, our study contributes to a better understanding of astrocyte heterogeneity in response to an injury. By characterizing the diverse reactive responses among astrocyte subpopulations, we provide insights that could guide future research aimed at identifying novel therapeutic targets to mitigate brain damage and promote neural repair.
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Affiliation(s)
- Lina M Delgado-García
- Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal-CSIC, Avenida Dr. Arce 37, 28002, Madrid, Spain
- Departamento de Bioquímica, Universidade Federal de Sao Paulo UNIFESP, Rua Pedro de Toledo 669, Sao Paulo, 04039032, Brazil
| | - Ana C Ojalvo-Sanz
- Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal-CSIC, Avenida Dr. Arce 37, 28002, Madrid, Spain
| | - Thabatta K E Nakamura
- Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal-CSIC, Avenida Dr. Arce 37, 28002, Madrid, Spain
- Departamento de Bioquímica, Universidade Federal de Sao Paulo UNIFESP, Rua Pedro de Toledo 669, Sao Paulo, 04039032, Brazil
| | - Eduardo Martín-López
- Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal-CSIC, Avenida Dr. Arce 37, 28002, Madrid, Spain
- Departments of Neurosurgery and Neuroscience, Yale University School of Medicine, 310 Cedar Street, New Haven, CT, 06510, USA
| | - Marimelia Porcionatto
- Departamento de Bioquímica, Universidade Federal de Sao Paulo UNIFESP, Rua Pedro de Toledo 669, Sao Paulo, 04039032, Brazil
| | - Laura Lopez-Mascaraque
- Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal-CSIC, Avenida Dr. Arce 37, 28002, Madrid, Spain.
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4
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Yakovlev EV, Simkin IV, Shirokova AA, Kolotieva NA, Novikova SV, Nasyrov AD, Denisenko IR, Gursky KD, Shishkov IN, Narzaeva DE, Salmina AB, Yurchenko SO, Kryuchkov NP. Machine learning approach for recognition and morphological analysis of isolated astrocytes in phase contrast microscopy. Sci Rep 2024; 14:9846. [PMID: 38684715 PMCID: PMC11059356 DOI: 10.1038/s41598-024-59773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 04/15/2024] [Indexed: 05/02/2024] Open
Abstract
Astrocytes are glycolytically active cells in the central nervous system playing a crucial role in various brain processes from homeostasis to neurotransmission. Astrocytes possess a complex branched morphology, frequently examined by fluorescent microscopy. However, staining and fixation may impact the properties of astrocytes, thereby affecting the accuracy of the experimental data of astrocytes dynamics and morphology. On the other hand, phase contrast microscopy can be used to study astrocytes morphology without affecting them, but the post-processing of the resulting low-contrast images is challenging. The main result of this work is a novel approach for recognition and morphological analysis of unstained astrocytes based on machine-learning recognition of microscopic images. We conducted a series of experiments involving the cultivation of isolated astrocytes from the rat brain cortex followed by microscopy. Using the proposed approach, we tracked the temporal evolution of the average total length of branches, branching, and area per astrocyte in our experiments. We believe that the proposed approach and the obtained experimental data will be of interest and benefit to the scientific communities in cell biology, biophysics, and machine learning.
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Affiliation(s)
- Egor V Yakovlev
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia.
| | - Ivan V Simkin
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Anastasiya A Shirokova
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Nataliya A Kolotieva
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
- Research Center of Neurology, 80 Volokolamskoye Shosse, Moscow, 125367, Russia
| | - Svetlana V Novikova
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
- Research Center of Neurology, 80 Volokolamskoye Shosse, Moscow, 125367, Russia
| | - Artur D Nasyrov
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Ilya R Denisenko
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Konstantin D Gursky
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Ivan N Shishkov
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Diana E Narzaeva
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
- Research Center of Neurology, 80 Volokolamskoye Shosse, Moscow, 125367, Russia
| | - Alla B Salmina
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
- Research Center of Neurology, 80 Volokolamskoye Shosse, Moscow, 125367, Russia
| | - Stanislav O Yurchenko
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia
| | - Nikita P Kryuchkov
- Scientific-Educational Centre "Soft matter and physics of fluids", Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, Moscow, 105005, Russia.
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5
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Czyżewski W, Mazurek M, Sakwa L, Szymoniuk M, Pham J, Pasierb B, Litak J, Czyżewska E, Turek M, Piotrowski B, Torres K, Rola R. Astroglial Cells: Emerging Therapeutic Targets in the Management of Traumatic Brain Injury. Cells 2024; 13:148. [PMID: 38247839 PMCID: PMC10813911 DOI: 10.3390/cells13020148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Traumatic Brain Injury (TBI) represents a significant health concern, necessitating advanced therapeutic interventions. This detailed review explores the critical roles of astrocytes, key cellular constituents of the central nervous system (CNS), in both the pathophysiology and possible rehabilitation of TBI. Following injury, astrocytes exhibit reactive transformations, differentiating into pro-inflammatory (A1) and neuroprotective (A2) phenotypes. This paper elucidates the interactions of astrocytes with neurons, their role in neuroinflammation, and the potential for their therapeutic exploitation. Emphasized strategies encompass the utilization of endocannabinoid and calcium signaling pathways, hormone-based treatments like 17β-estradiol, biological therapies employing anti-HBGB1 monoclonal antibodies, gene therapy targeting Connexin 43, and the innovative technique of astrocyte transplantation as a means to repair damaged neural tissues.
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Affiliation(s)
- Wojciech Czyżewski
- Department of Didactics and Medical Simulation, Medical University of Lublin, 20-954 Lublin, Poland;
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
| | - Marek Mazurek
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
| | - Leon Sakwa
- Student Scientific Society, Kazimierz Pulaski University of Radom, 26-600 Radom, Poland;
| | - Michał Szymoniuk
- Student Scientific Association, Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Jennifer Pham
- Student Scientific Society, Medical University of Lublin, 20-954 Lublin, Poland; (J.P.); (M.T.)
| | - Barbara Pasierb
- Department of Dermatology, Radom Specialist Hospital, 26-600 Radom, Poland;
| | - Jakub Litak
- Department of Clinical Immunology, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Ewa Czyżewska
- Department of Otolaryngology, Mazovian Specialist Hospital, 26-617 Radom, Poland;
| | - Michał Turek
- Student Scientific Society, Medical University of Lublin, 20-954 Lublin, Poland; (J.P.); (M.T.)
| | - Bartłomiej Piotrowski
- Institute of Automatic Control and Robotics, Warsaw University of Technology, 00-661 Warsaw, Poland;
| | - Kamil Torres
- Department of Didactics and Medical Simulation, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Radosław Rola
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
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6
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Dhyani V, George K, Gare S, Venkatesh KV, Mitra K, Giri L. A computational model to uncover the biophysical underpinnings of neural firing heterogeneity in dissociated hippocampal cultures. Hippocampus 2023; 33:1208-1227. [PMID: 37705290 DOI: 10.1002/hipo.23575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 07/12/2023] [Accepted: 08/21/2023] [Indexed: 09/15/2023]
Abstract
Calcium (Ca2+ ) imaging reveals a variety of correlated firing in cultures of dissociated hippocampal neurons, pinpointing the non-synaptic paracrine release of glutamate as a possible mediator for such firing patterns, although the biophysical underpinnings remain unknown. An intriguing possibility is that extracellular glutamate could bind metabotropic receptors linked with inositol trisphosphate (IP3 ) mediated release of Ca2+ from the endoplasmic reticulum of individual neurons, thereby modulating neural activity in combination with sarco/endoplasmic reticulum Ca2+ transport ATPase (SERCA) and voltage-gated Ca2+ channels (VGCC). However, the possibility that such release may occur in different neuronal compartments and can be inherently stochastic poses challenges in the characterization of such interplay between various Ca2+ channels. Here we deploy biophysical modeling in association with Monte Carlo parameter sampling to characterize such interplay and successfully predict experimentally observed Ca2+ patterns. The results show that the neurotransmitter level at the plasma membrane is the extrinsic source of heterogeneity in somatic Ca2+ transients. Our analysis, in particular, identifies the origin of such heterogeneity to an intrinsic differentiation of hippocampal neurons in terms of multiple cellular properties pertaining to intracellular Ca2+ signaling, such as VGCC, IP3 receptor, and SERCA expression. In the future, the biophysical model and parameter estimation approach used in this study can be upgraded to predict the response of a system of interconnected neurons.
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Affiliation(s)
- Vaibhav Dhyani
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
- Optical Science Centre, Faculty of Science, Engineering & Technology, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Kevin George
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
| | - Suman Gare
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
| | - K V Venkatesh
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, India
| | - Kishalay Mitra
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
| | - Lopamudra Giri
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
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7
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Brazhe A, Verisokin A, Verveyko D, Postnov D. Astrocytes: new evidence, new models, new roles. Biophys Rev 2023; 15:1303-1333. [PMID: 37975000 PMCID: PMC10643736 DOI: 10.1007/s12551-023-01145-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/08/2023] [Indexed: 11/19/2023] Open
Abstract
Astrocytes have been in the limelight of active research for about 3 decades now. Over this period, ideas about their function and role in the nervous system have evolved from simple assistance in energy supply and homeostasis maintenance to a complex informational and metabolic hub that integrates data on local neuronal activity, sensory and arousal context, and orchestrates many crucial processes in the brain. Rapid progress in experimental techniques and data analysis produces a growing body of data, which can be used as a foundation for formulation of new hypotheses, building new refined mathematical models, and ultimately should lead to a new level of understanding of the contribution of astrocytes to the cognitive tasks performed by the brain. Here, we highlight recent progress in astrocyte research, which we believe expands our understanding of how low-level signaling at a cellular level builds up to processes at the level of the whole brain and animal behavior. We start our review with revisiting data on the role of noradrenaline-mediated astrocytic signaling in locomotion, arousal, sensory integration, memory, and sleep. We then briefly review astrocyte contribution to the regulation of cerebral blood flow regulation, which is followed by a discussion of biophysical mechanisms underlying astrocyte effects on different brain processes. The experimental section is closed by an overview of recent experimental techniques available for modulation and visualization of astrocyte dynamics. We then evaluate how the new data can be potentially incorporated into the new mathematical models or where and how it already has been done. Finally, we discuss an interesting prospect that astrocytes may be key players in important processes such as the switching between sleep and wakefulness and the removal of toxic metabolites from the brain milieu.
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Affiliation(s)
- Alexey Brazhe
- Department of Biophysics, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory, 1/24, Moscow, 119234 Russia
- Department of Molecular Neurobiology, Institute of Bioorganic Chemistry RAS, GSP-7, Miklukho-Maklay Str., 16/10, Moscow, 117997 Russia
| | - Andrey Verisokin
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Darya Verveyko
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya st., 83, Saratov, 410012 Russia
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8
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Farina S, Voorsluijs V, Fixemer S, Bouvier DS, Claus S, Ellisman MH, Bordas SPA, Skupin A. Mechanistic multiscale modelling of energy metabolism in human astrocytes reveals the impact of morphology changes in Alzheimer's Disease. PLoS Comput Biol 2023; 19:e1011464. [PMID: 37729344 PMCID: PMC10545114 DOI: 10.1371/journal.pcbi.1011464] [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: 03/16/2023] [Revised: 10/02/2023] [Accepted: 08/25/2023] [Indexed: 09/22/2023] Open
Abstract
Astrocytes with their specialised morphology are essential for brain homeostasis as metabolic mediators between blood vessels and neurons. In neurodegenerative diseases such as Alzheimer's disease (AD), astrocytes adopt reactive profiles with molecular and morphological changes that could lead to the impairment of their metabolic support and impact disease progression. However, the underlying mechanisms of how the metabolic function of human astrocytes is impaired by their morphological changes in AD are still elusive. To address this challenge, we developed and applied a metabolic multiscale modelling approach integrating the dynamics of metabolic energy pathways and physiological astrocyte morphologies acquired in human AD and age-matched control brain samples. The results demonstrate that the complex cell shape and intracellular organisation of energetic pathways determine the metabolic profile and support capacity of astrocytes in health and AD conditions. Thus, our mechanistic approach indicates the importance of spatial orchestration in metabolism and allows for the identification of protective mechanisms against disease-associated metabolic impairments.
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Affiliation(s)
- Sofia Farina
- Department of Engineering, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Valérie Voorsluijs
- LCSB-Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Department of Physics and Material Science, University of Luxembourg, Luxembourg, Luxembourg
| | - Sonja Fixemer
- LCSB-Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Luxembourg Center of Neuropathology (LCNP), Dudelange, Luxembourg
| | - David S. Bouvier
- LCSB-Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Luxembourg Center of Neuropathology (LCNP), Dudelange, Luxembourg
- Laboratoire national de santé (LNS), National Center of Pathology (NCP), Dudelange, Luxembourg
| | | | - Mark H. Ellisman
- Department of Neurosciences, University of California San Diego, California, United States of America
| | | | - Alexander Skupin
- LCSB-Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Department of Physics and Material Science, University of Luxembourg, Luxembourg, Luxembourg
- Department of Neurosciences, University of California San Diego, California, United States of America
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9
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Fritschi L, Lenk K. Parameter Inference for an Astrocyte Model using Machine Learning Approaches. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.540982. [PMID: 37292854 PMCID: PMC10245674 DOI: 10.1101/2023.05.16.540982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Astrocytes are the largest subset of glial cells and perform structural, metabolic, and regulatory functions. They are directly involved in the communication at neuronal synapses and the maintenance of brain homeostasis. Several disorders, such as Alzheimer's, epilepsy, and schizophrenia, have been associated with astrocyte dysfunction. Computational models on various spatial levels have been proposed to aid in the understanding and research of astrocytes. The difficulty of computational astrocyte models is to fastly and precisely infer parameters. Physics informed neural networks (PINNs) use the underlying physics to infer parameters and, if necessary, dynamics that can not be observed. We have applied PINNs to estimate parameters for a computational model of an astrocytic compartment. The addition of two techniques helped with the gradient pathologies of the PINNS, the dynamic weighting of various loss components and the addition of Transformers. To overcome the issue that the neural network only learned the time dependence but did not know about eventual changes of the input stimulation to the astrocyte model, we followed an adaptation of PINNs from control theory (PINCs). In the end, we were able to infer parameters from artificial, noisy data, with stable results for the computational astrocyte model.
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Affiliation(s)
| | - Kerstin Lenk
- Institute of Neural Engineering, Graz University of Technology, Graz, Austria
- BioTechMed, 8010 Graz, Austria
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10
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Fedotova A, Brazhe A, Doronin M, Toptunov D, Pryazhnikov E, Khiroug L, Verkhratsky A, Semyanov A. Dissociation Between Neuronal and Astrocytic Calcium Activity in Response to Locomotion in Mice. FUNCTION 2023; 4:zqad019. [PMID: 37342415 PMCID: PMC10278990 DOI: 10.1093/function/zqad019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 06/22/2023] Open
Abstract
Locomotion triggers a coordinated response of both neurons and astrocytes in the brain. Here we performed calcium (Ca2+) imaging of these two cell types in the somatosensory cortex in head-fixed mice moving on the airlifted platform. Ca2+ activity in astrocytes significantly increased during locomotion from a low quiescence level. Ca2+ signals first appeared in the distal processes and then propagated to astrocytic somata, where it became significantly larger and exhibited oscillatory behaviour. Thus, astrocytic soma operates as both integrator and amplifier of Ca2+ signal. In neurons, Ca2+ activity was pronounced in quiescent periods and further increased during locomotion. Neuronal Ca2+ concentration ([Ca2+]i) rose almost immediately following the onset of locomotion, whereas astrocytic Ca2+ signals lagged by several seconds. Such a long lag suggests that astrocytic [Ca2+]i elevations are unlikely to be triggered by the activity of synapses among local neurons. Ca2+ responses to pairs of consecutive episodes of locomotion did not significantly differ in neurons, while were significantly diminished in response to the second locomotion in astrocytes. Such astrocytic refractoriness may arise from distinct mechanisms underlying Ca2+ signal generation. In neurons, the bulk of Ca2+ enters through the Ca2+ channels in the plasma membrane allowing for steady-level Ca2+ elevations in repetitive runs. Astrocytic Ca2+ responses originate from the intracellular stores, the depletion of which affects subsequent Ca2+ signals. Functionally, neuronal Ca2+ response reflects sensory input processed by neurons. Astrocytic Ca2+ dynamics is likely to provide metabolic and homeostatic support within the brain active milieu.
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Affiliation(s)
- Anna Fedotova
- Faculty of Biology, Moscow State University, Moscow 119991, Russia
- Department of Molecular Neurobiology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
| | - Alexey Brazhe
- Faculty of Biology, Moscow State University, Moscow 119991, Russia
- Department of Molecular Neurobiology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
| | - Maxim Doronin
- Department of Molecular Neurobiology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow 117997, Russia
- College of Medicine, Jiaxing University, Jiaxing, Zhejiang Province, 314001, China
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11
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Salmon CK, Syed TA, Kacerovsky JB, Alivodej N, Schober AL, Sloan TFW, Pratte MT, Rosen MP, Green M, Chirgwin-Dasgupta A, Mehta S, Jilani A, Wang Y, Vali H, Mandato CA, Siddiqi K, Murai KK. Organizing principles of astrocytic nanoarchitecture in the mouse cerebral cortex. Curr Biol 2023; 33:957-972.e5. [PMID: 36805126 DOI: 10.1016/j.cub.2023.01.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/01/2022] [Accepted: 01/20/2023] [Indexed: 02/18/2023]
Abstract
Astrocytes are increasingly understood to be important regulators of central nervous system (CNS) function in health and disease; yet, we have little quantitative understanding of their complex architecture. While broad categories of astrocytic structures are known, the discrete building blocks that compose them, along with their geometry and organizing principles, are poorly understood. Quantitative investigation of astrocytic complexity is impeded by the absence of high-resolution datasets and robust computational approaches to analyze these intricate cells. To address this, we produced four ultra-high-resolution datasets of mouse cerebral cortex using serial electron microscopy and developed astrocyte-tailored computer vision methods for accurate structural analysis. We unearthed specific anatomical building blocks, structural motifs, connectivity hubs, and hierarchical organizations of astrocytes. Furthermore, we found that astrocytes interact with discrete clusters of synapses and that astrocytic mitochondria are distributed to lie closer to larger clusters of synapses. Our findings provide a geometrically principled, quantitative understanding of astrocytic nanoarchitecture and point to an unexpected level of complexity in how astrocytes interact with CNS microanatomy.
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Affiliation(s)
- Christopher K Salmon
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Tabish A Syed
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada; MILA - Québec AI Institute, 6666 Rue Saint-Urbain, Montreal, QC H2S 3H1, Canada
| | - J Benjamin Kacerovsky
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Nensi Alivodej
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Alexandra L Schober
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | | | - Michael T Pratte
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Michael P Rosen
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Miranda Green
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Adario Chirgwin-Dasgupta
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Shaurya Mehta
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Affan Jilani
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Yanan Wang
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Hojatollah Vali
- Department of Anatomy & Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
| | - Craig A Mandato
- Department of Anatomy & Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
| | - Kaleem Siddiqi
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada; MILA - Québec AI Institute, 6666 Rue Saint-Urbain, Montreal, QC H2S 3H1, Canada.
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada.
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12
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Liu L, Gao H, Li J, Chen S. Probing microdomain Ca 2+ activity and synaptic transmission with a node-based tripartite synapse model. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1111306. [PMID: 36926546 PMCID: PMC10013067 DOI: 10.3389/fnetp.2023.1111306] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/27/2023] [Indexed: 06/08/2023]
Abstract
Astrocytic fine processes are the most minor structures of astrocytes but host much of the Ca2+ activity. These localized Ca2+ signals spatially restricted to microdomains are crucial for information processing and synaptic transmission. However, the mechanistic link between astrocytic nanoscale processes and microdomain Ca2+ activity remains hazily understood because of the technical difficulties in accessing this structurally unresolved region. In this study, we used computational models to disentangle the intricate relations of morphology and local Ca2+ dynamics involved in astrocytic fine processes. We aimed to answer: 1) how nano-morphology affects local Ca2+ activity and synaptic transmission, 2) and how fine processes affect Ca2+ activity of large process they connect. To address these issues, we undertook the following two computational modeling: 1) we integrated the in vivo astrocyte morphological data from a recent study performed with super-resolution microscopy that discriminates sub-compartments of various shapes, referred to as nodes and shafts to a classic IP3R-mediated Ca2+ signaling framework describing the intracellular Ca2+ dynamics, 2) we proposed a node-based tripartite synapse model linking with astrocytic morphology to predict the effect of structural deficits of astrocytes on synaptic transmission. Extensive simulations provided us with several biological insights: 1) the width of nodes and shafts could strongly influence the spatiotemporal variability of Ca2+ signals properties but what indeed determined the Ca2+ activity was the width ratio between nodes and shafts, 2) the connectivity of nodes to larger processes markedly shaped the Ca2+ signal of the parent process rather than nodes morphology itself, 3) the morphological changes of astrocytic part might potentially induce the abnormality of synaptic transmission by affecting the level of glutamate at tripartite synapses. Taken together, this comprehensive model which integrated theoretical computation and in vivo morphological data highlights the role of the nanomorphology of astrocytes in signal transmission and its possible mechanisms related to pathological conditions.
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Affiliation(s)
- Langzhou Liu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Huayi Gao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Jinyu Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbin Chen
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
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13
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Nanotopography and Microconfinement Impact on Primary Hippocampal Astrocyte Morphology, Cytoskeleton and Spontaneous Calcium Wave Signalling. Cells 2023; 12:cells12020293. [PMID: 36672231 PMCID: PMC9856934 DOI: 10.3390/cells12020293] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/19/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Astrocytes' organisation affects the functioning and the fine morphology of the brain, both in physiological and pathological contexts. Although many aspects of their role have been characterised, their complex functions remain, to a certain extent, unclear with respect to their contribution to brain cell communication. Here, we studied the effects of nanotopography and microconfinement on primary hippocampal rat astrocytes. For this purpose, we fabricated nanostructured zirconia surfaces as homogenous substrates and as micrometric patterns, the latter produced by a combination of an additive nanofabrication and micropatterning technique. These engineered substrates reproduce both nanotopographical features and microscale geometries that astrocytes encounter in their natural environment, such as basement membrane topography, as well as blood vessels and axonal fibre topology. The impact of restrictive adhesion manifests in the modulation of several cellular properties of single cells (morphological and actin cytoskeletal changes) and the network organisation and functioning. Calcium wave signalling was observed only in astrocytes grown in confined geometries, with an activity enhancement in cells forming elongated agglomerates with dimensions typical of blood vessels or axon fibres. Our results suggest that calcium oscillation and wave propagation are closely related to astrocytic morphology and actin cytoskeleton organisation.
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14
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Kumar BS, Menon SC, Gayathri SR, Chakravarthy VS. The Influence of Neural Activity and Neural Cytoarchitecture on Cerebrovascular Arborization: A Computational Model. Front Neurosci 2022; 16:917196. [PMID: 35860300 PMCID: PMC9290769 DOI: 10.3389/fnins.2022.917196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 05/30/2022] [Indexed: 11/18/2022] Open
Abstract
Normal functioning of the brain relies on a continual and efficient delivery of energy by a vast network of cerebral blood vessels. The bidirectional coupling between neurons and blood vessels consists of vasodilatory energy demand signals from neurons to blood vessels, and the retrograde flow of energy substrates from the vessels to neurons, which fuel neural firing, growth and other housekeeping activities in the neurons. Recent works indicate that, in addition to the functional coupling observed in the adult brain, the interdependence between the neural and vascular networks begins at the embryonic stage, and continues into subsequent developmental stages. The proposed Vascular Arborization Model (VAM) captures the effect of neural cytoarchitecture and neural activity on vascular arborization. The VAM describes three important stages of vascular tree growth: (i) The prenatal growth phase, where the vascular arborization depends on the cytoarchitecture of neurons and non-neural cells, (ii) the post-natal growth phase during which the further arborization of the vasculature depends on neural activity in addition to neural cytoarchitecture, and (iii) the settling phase, where the fully grown vascular tree repositions its vascular branch points or nodes to ensure minimum path length and wire length. The vasculature growth depicted by VAM captures structural characteristics like vascular volume density, radii, mean distance to proximal neurons in the cortex. VAM-grown vasculature agrees with the experimental observation that the neural densities do not covary with the vascular density along the depth of the cortex but predicts a high correlation between neural areal density and microvascular density when compared over a global scale (across animals and regions). To explore the influence of neural activity on vascular arborization, the VAM was used to grow the vasculature in neonatal rat whisker barrel cortex under two conditions: (i) Control, where the whiskers were intact and (ii) Lesioned, where one row of whiskers was cauterized. The model captures a significant reduction in vascular branch density in lesioned animals compared to control animals, concurring with experimental observation.
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Affiliation(s)
- Bhadra S. Kumar
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Sarath C. Menon
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
| | | | - V. Srinivasa Chakravarthy
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
- Center for Complex Systems and Dynamics, Indian Institute of Technology Madras, Chennai, India
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15
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Yuan Z, Feng P, Fan Y, Yu Y, Wu Y. Astrocytic modulation on neuronal electric mode selection induced by magnetic field effect. Cogn Neurodyn 2022; 16:183-194. [PMID: 35126777 PMCID: PMC8807809 DOI: 10.1007/s11571-021-09709-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/11/2021] [Accepted: 07/20/2021] [Indexed: 02/03/2023] Open
Abstract
Astrocytes as well as electromagnetic induction have been primarily considered as main factors in regulating neuronal firing patterns in the recent decade. In this work, an improved neuron-astrocyte model in consideration of the modulation of astrocytes and the electromagnetic induction is employed to explore the extend to which both of the factors affect the firing modes of the neurons. The "alternation mode", defined as the alternative of neural normal spiking mode with the high-frequency bursting-like mode, clearly shows the functions of astrocytes on neurons. Moreover, the firing pattern of the neuron becomes more abnormal when astrocytes are hyper-excitable, the reason why the abnormal coupling of the astrocyte leads to the "alternation mode" of the neuron have been studied. In addition, the effect of electromagnetic induction manifests nonlinear characteristic towards neurons, complex firing modes of neurons are observed in the weaker field and a switching mode consists with quiescent and spiking mode appears when there is a higher stronger field. This approved model can reveal the normal or abnormal electric activities of neuron considered electromagnetic induction induced by the degree of excitability of the astrocyte. These results can provide potential understanding about the effects of astrocyte on neuronal activity when the coupling of electromagnetic field is considered.
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Affiliation(s)
- Zhixuan Yuan
- State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures, School of Aerospace Engineering, Xian Jiaotong University, Xian, 710049 China
| | - Peihua Feng
- State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures, School of Aerospace Engineering, Xian Jiaotong University, Xian, 710049 China
| | - Yongchen Fan
- State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures, School of Aerospace Engineering, Xian Jiaotong University, Xian, 710049 China
| | - Yangyang Yu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures, School of Aerospace Engineering, Xian Jiaotong University, Xian, 710049 China
| | - Ying Wu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures, School of Aerospace Engineering, Xian Jiaotong University, Xian, 710049 China
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