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Kagan BJ, Gyngell C, Lysaght T, Cole VM, Sawai T, Savulescu J. The technology, opportunities, and challenges of Synthetic Biological Intelligence. Biotechnol Adv 2023; 68:108233. [PMID: 37558186 PMCID: PMC7615149 DOI: 10.1016/j.biotechadv.2023.108233] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/15/2023] [Accepted: 08/05/2023] [Indexed: 08/11/2023]
Abstract
Integrating neural cultures developed through synthetic biology methods with digital computing has enabled the early development of Synthetic Biological Intelligence (SBI). Recently, key studies have emphasized the advantages of biological neural systems in some information processing tasks. However, neither the technology behind this early development, nor the potential ethical opportunities or challenges, have been explored in detail yet. Here, we review the key aspects that facilitate the development of SBI and explore potential applications. Considering these foreseeable use cases, various ethical implications are proposed. Ultimately, this work aims to provide a robust framework to structure ethical considerations to ensure that SBI technology can be both researched and applied responsibly.
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Affiliation(s)
| | - Christopher Gyngell
- Murdoch Children's Research Institute, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia
| | - Tamra Lysaght
- Centre for Biomedical Ethics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Victor M Cole
- Centre for Biomedical Ethics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Tsutomu Sawai
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan; Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Kyoto, Japan
| | - Julian Savulescu
- Murdoch Children's Research Institute, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia; Centre for Biomedical Ethics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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2
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Lee H, Yi GS, Nam Y. Connectivity and network burst properties of in-vitro neuronal networks induced by a clustered structure with alginate hydrogel patterning. Biomed Eng Lett 2023; 13:659-670. [PMID: 37872997 PMCID: PMC10590365 DOI: 10.1007/s13534-023-00289-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 10/25/2023] Open
Abstract
Modularity is one of the important structural properties that affect information processing and other functionalities of neuronal networks. Researchers have developed in-vitro clustered network models for reproducing the modularity, but it is still challenging to control the segregation and integration of several sub-populations of them. We cultured clustered networks with alginate patterning and collected the electrophysiological signals to investigate the changes in functional properties during the development. We built inter-connected neuronal clusters using alginate micro-patterning with a circular shape on the surface of the micro-electrode array. The neuronal clusters were enabled to be connected at 3 or 10 days-in-vitro (DIV) by removing the barrier. The neuronal signals from different types of networks were collected from 16 to 34 DIV, and functional characteristics were examined. Connectivity and burst motif analysis were carried out to find out the relation between the structure and function of the networks. Neuronal networks with clustered structure showed different activity properties from the random networks along the development. The clustered networks had more short-range connections compared to the random networks. In the network burst motif analysis, the clustered networks showed more various patterns and a slower propagation of the activation patterns. In this study, we successfully cultured neuronal networks with clustered structure, and the structure affected the functional properties. The network model suggested in this study will be a good solution for observing the effect of structure on function during their development. Supplementary Information The online version contains supplementary material available at 10.1007/s13534-023-00289-5.
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Affiliation(s)
- Hyungsub Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
| | - Gwan-Su Yi
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
| | - Yoonkey Nam
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
- KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
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3
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Stasenko SV, Hramov AE, Kazantsev VB. Loss of neuron network coherence induced by virus-infected astrocytes: a model study. Sci Rep 2023; 13:6401. [PMID: 37076526 PMCID: PMC10115799 DOI: 10.1038/s41598-023-33622-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/15/2023] [Indexed: 04/21/2023] Open
Abstract
Coherent activations of brain neuron networks underlie many physiological functions associated with various behavioral states. These synchronous fluctuations in the electrical activity of the brain are also referred to as brain rhythms. At the cellular level, rhythmicity can be induced by various mechanisms of intrinsic oscillations in neurons or the network circulation of excitation between synaptically coupled neurons. One specific mechanism concerns the activity of brain astrocytes that accompany neurons and can coherently modulate synaptic contacts of neighboring neurons, synchronizing their activity. Recent studies have shown that coronavirus infection (Covid-19), which enters the central nervous system and infects astrocytes, can cause various metabolic disorders. Specifically, Covid-19 can depress the synthesis of astrocytic glutamate and gamma-aminobutyric acid. It is also known that in the post-Covid state, patients may suffer from symptoms of anxiety and impaired cognitive functions. We propose a mathematical model of a spiking neuron network accompanied by astrocytes capable of generating quasi-synchronous rhythmic bursting discharges. The model predicts that if the release of glutamate is depressed, normal burst rhythmicity will suffer dramatically. Interestingly, in some cases, the failure of network coherence may be intermittent, with intervals of normal rhythmicity, or the synchronization can disappear.
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Affiliation(s)
- Sergey V Stasenko
- Scientific-educational mathematical center "Mathematics of future technologies", Lobachevsky University, Nizhniy Novgorod, Russia, 603022.
- Laboratory of neurobiomorphic technologies, Moscow Institute of Physics and Technology, Moscow, Russia, 117303.
| | - Alexander E Hramov
- Baltic Center for Artificial Intelligence and Neurotechnology, Immanuel Kant Baltic Federal University, Kaliningrad, Russia, 236041
- Neuroscience Research Institute, Samara State Medical University, Samara, Russia, 443099
| | - Victor B Kazantsev
- Scientific-educational mathematical center "Mathematics of future technologies", Lobachevsky University, Nizhniy Novgorod, Russia, 603022
- Laboratory of neurobiomorphic technologies, Moscow Institute of Physics and Technology, Moscow, Russia, 117303
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Kim E, Jeon S, Yang YS, Jin C, Kim JY, Oh YS, Rah JC, Choi H. A Neurospheroid-Based Microrobot for Targeted Neural Connections in a Hippocampal Slice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208747. [PMID: 36640750 DOI: 10.1002/adma.202208747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Functional restoration by the re-establishment of cellular or neural connections remains a major challenge in targeted cell therapy and regenerative medicine. Recent advances in magnetically powered microrobots have shown potential for use in controlled and targeted cell therapy. In this study, a magnetic neurospheroid (Mag-Neurobot) that can form both structural and functional connections with an organotypic hippocampal slice (OHS) is assessed using an ex vivo model as a bridge toward in vivo application. The Mag-Neurobot consists of hippocampal neurons and superparamagnetic nanoparticles (SPIONs); it is precisely and skillfully manipulated by an external magnetic field. Furthermore, the results of patch-clamp recordings of hippocampal neurons indicate that neither the neuronal excitabilities nor the synaptic functions of SPION-loaded cells are significantly affected. Analysis of neural activity propagation using high-density multi-electrode arrays shows that the delivered Mag-Neurobot is functionally connected with the OHS. The applications of this study include functional verification for targeted cell delivery through the characterization of novel synaptic connections and the functionalities of transported and transplanted cells. The success of the Mag-Neurobot opens up new avenues of research and application; it offers a test platform for functional neural connections and neural regenerative processes through cell transplantation.
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Affiliation(s)
- Eunhee Kim
- IMsystem Co., Ltd., 333, Technojungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Sungwoong Jeon
- IMsystem Co., Ltd., 333, Technojungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Yoon-Sil Yang
- Emerging Infectious Disease Vaccines Division, National Institute of Food and Drug Safety Evaluation, 187, Osongsaengmyeong 2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Republic of Korea
- Korea Brain Research Institute, 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
| | - Chaewon Jin
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Jin-Young Kim
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Department of Robotics and Mechatronics Engineering, DGIST, Daegu, 42988, Republic of Korea
| | - Yong-Seok Oh
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Jong-Cheol Rah
- Korea Brain Research Institute, 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Hongsoo Choi
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Department of Robotics and Mechatronics Engineering, DGIST, Daegu, 42988, Republic of Korea
- Robotics and Mechatronics Engineering Research Center, DGIST, Daegu, 42988, Republic of Korea
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5
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Weir JS, Christiansen N, Sandvig A, Sandvig I. Selective inhibition of excitatory synaptic transmission alters the emergent bursting dynamics of in vitro neural networks. Front Neural Circuits 2023; 17:1020487. [PMID: 36874945 PMCID: PMC9978115 DOI: 10.3389/fncir.2023.1020487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/31/2023] [Indexed: 02/18/2023] Open
Abstract
Neurons in vitro connect to each other and form neural networks that display emergent electrophysiological activity. This activity begins as spontaneous uncorrelated firing in the early phase of development, and as functional excitatory and inhibitory synapses mature, the activity typically emerges as spontaneous network bursts. Network bursts are events of coordinated global activation among many neurons interspersed with periods of silencing and are important for synaptic plasticity, neural information processing, and network computation. While bursting is the consequence of balanced excitatory-inhibitory (E/I) interactions, the functional mechanisms underlying their evolution from physiological to potentially pathophysiological states, such as decreasing or increasing in synchrony, are still poorly understood. Synaptic activity, especially that related to maturity of E/I synaptic transmission, is known to strongly influence these processes. In this study, we used selective chemogenetic inhibition to target and disrupt excitatory synaptic transmission in in vitro neural networks to study functional response and recovery of spontaneous network bursts over time. We found that over time, inhibition resulted in increases in both network burstiness and synchrony. Our results indicate that the disruption in excitatory synaptic transmission during early network development likely affected inhibitory synaptic maturity which resulted in an overall decrease in network inhibition at later stages. These findings lend support to the importance of E/I balance in maintaining physiological bursting dynamics and, conceivably, information processing capacity in neural networks.
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Affiliation(s)
- Janelle Shari Weir
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nicholas Christiansen
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway.,Division of Neuro, Head and Neck, Department of Pharmacology and Clinical Neurosciences, Umeå University Hospital, Umeå, Sweden.,Division of Neuro, Head and Neck, Department of Community Medicine and Rehabilitation, Umeå University Hospital, Umeå, Sweden
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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Cohen LD, Ziv T, Ziv NE. Synapse integrity and function: Dependence on protein synthesis and identification of potential failure points. Front Mol Neurosci 2022; 15:1038614. [PMID: 36583084 PMCID: PMC9792512 DOI: 10.3389/fnmol.2022.1038614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/07/2022] [Indexed: 12/14/2022] Open
Abstract
Synaptic integrity and function depend on myriad proteins - labile molecules with finite lifetimes that need to be continually replaced with freshly synthesized copies. Here we describe experiments designed to expose synaptic (and neuronal) properties and functions that are particularly sensitive to disruptions in protein supply, identify proteins lost early upon such disruptions, and uncover potential, yet currently underappreciated failure points. We report here that acute suppressions of protein synthesis are followed within hours by reductions in spontaneous network activity levels, impaired oxidative phosphorylation and mitochondrial function, and, importantly, destabilization and loss of both excitatory and inhibitory postsynaptic specializations. Conversely, gross impairments in presynaptic vesicle recycling occur over longer time scales (days), as does overt cell death. Proteomic analysis identified groups of potentially essential 'early-lost' proteins including regulators of synapse stability, proteins related to bioenergetics, fatty acid and lipid metabolism, and, unexpectedly, numerous proteins involved in Alzheimer's disease pathology and amyloid beta processing. Collectively, these findings point to neuronal excitability, energy supply and synaptic stability as early-occurring failure points under conditions of compromised supply of newly synthesized protein copies.
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Affiliation(s)
- Laurie D. Cohen
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Haifa, Israel
| | - Tamar Ziv
- Smoler Proteomics Center, Lokey Interdisciplinary Center for Life Sciences & Engineering, Technion, Haifa, Israel
| | - Noam E. Ziv
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Haifa, Israel,*Correspondence: Noam E. Ziv,
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Lemercier CE, Garenne A, Poulletier de Gannes F, El Khoueiry C, Arnaud-Cormos D, Levêque P, Lagroye I, Percherancier Y, Lewis N. Comparative study between radiofrequency-induced and muscimol-induced inhibition of cultured networks of cortical neuron. PLoS One 2022; 17:e0268605. [PMID: 36044461 PMCID: PMC9432733 DOI: 10.1371/journal.pone.0268605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022] Open
Abstract
Previous studies have shown that spontaneously active cultured networks of cortical neuron grown planar microelectrode arrays are sensitive to radiofrequency (RF) fields and exhibit an inhibitory response more pronounced as the exposure time and power increase. To better understand the mechanism behind the observed effects, we aimed at identifying similarities and differences between the inhibitory effect of RF fields (continuous wave, 1800 MHz) to the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol (MU). Inhibition of the network bursting activity in response to RF exposure became apparent at an SAR level of 28.6 W/kg and co-occurred with an elevation of the culture medium temperature of ~1°C. Exposure to RF fields preferentially inhibits bursting over spiking activity and exerts fewer constraints on neural network bursting synchrony, differentiating it from a pharmacological inhibition with MU. Network rebound excitation, a phenomenon relying on the intrinsic properties of cortical neurons, was observed following the removal of tonic hyperpolarization after washout of MU but not in response to cessation of RF exposure. This implies that hyperpolarization is not the main driving force mediating the inhibitory effects of RF fields. At the level of single neurons, network inhibition induced by MU and RF fields occurred with reduced action potential (AP) half-width. As changes in AP waveform strongly influence efficacy of synaptic transmission, the narrowing effect on AP seen under RF exposure might contribute to reducing network bursting activity. By pointing only to a partial overlap between the inhibitory hallmarks of these two forms of inhibition, our data suggest that the inhibitory mechanisms of the action of RF fields differ from the ones mediated by the activation of GABAA receptors.
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Affiliation(s)
- Clément E. Lemercier
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
- Faculty of Medicine, Institute of Physiology, Department of Systems Neuroscience, Ruhr University Bochum, Bochum, Germany
- * E-mail: (CEL); (NL)
| | - André Garenne
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
| | | | - Corinne El Khoueiry
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
| | - Delia Arnaud-Cormos
- Univ. Limoges, CNRS, XLIM, UMR 7252, Limoges, France
- Institut Universitaire de France (IUF), Paris, France
| | | | - Isabelle Lagroye
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
- Paris “Sciences et Lettres” Research University, Paris, France
| | - Yann Percherancier
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
| | - Noëlle Lewis
- Laboratoire de l’Intégration du Matériau au Système, CNRS UMR 5218, University of Bordeaux, Talence, France
- * E-mail: (CEL); (NL)
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8
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Jia X, Shao W, Hu N, Shi J, Fan X, Chen C, Wang Y, Chen L, Qiao H, Li X. Learning populations with hubs govern the initiation and propagation of spontaneous bursts in neuronal networks after learning. Front Neurosci 2022; 16:854199. [PMID: 36061604 PMCID: PMC9433803 DOI: 10.3389/fnins.2022.854199] [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: 01/13/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
Spontaneous bursts in neuronal networks with propagation involving a large number of synchronously firing neurons are considered to be a crucial feature of these networks both in vivo and in vitro. Recently, learning has been shown to improve the association and synchronization of spontaneous events in neuronal networks by promoting the firing of spontaneous bursts. However, little is known about the relationship between the learning phase and spontaneous bursts. By combining high-resolution measurement with a 4,096-channel complementary metal-oxide-semiconductor (CMOS) microelectrode array (MEA) and graph theory, we studied how the learning phase influenced the initiation of spontaneous bursts in cultured networks of rat cortical neurons in vitro. We found that a small number of selected populations carried most of the stimulus information and contributed to learning. Moreover, several new burst propagation patterns appeared in spontaneous firing after learning. Importantly, these "learning populations" had more hubs in the functional network that governed the initiation of spontaneous burst activity. These results suggest that changes in the functional structure of learning populations may be the key mechanism underlying increased bursts after learning. Our findings could increase understanding of the important role that synaptic plasticity plays in the regulation of spontaneous activity.
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Affiliation(s)
- Xiaoli Jia
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Wenwei Shao
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Nan Hu
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Jianxin Shi
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Xiu Fan
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Chong Chen
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Youwei Wang
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Liqun Chen
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Huanhuan Qiao
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
| | - Xiaohong Li
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin, China
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Shokoohimehr P, Cepkenovic B, Milos F, Bednár J, Hassani H, Maybeck V, Offenhäusser A. High-Aspect-Ratio Nanoelectrodes Enable Long-Term Recordings of Neuronal Signals with Subthreshold Resolution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200053. [PMID: 35527345 DOI: 10.1002/smll.202200053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/24/2022] [Indexed: 06/14/2023]
Abstract
The further development of neurochips requires high-density and high-resolution recordings that also allow neuronal signals to be observed over a long period of time. Expanding fields of network neuroscience and neuromorphic engineering demand the multiparallel and direct estimations of synaptic weights, and the key objective is to construct a device that also records subthreshold events. Recently, 3D nanostructures with a high aspect ratio have become a particularly suitable interface between neurons and electronic devices, since the excellent mechanical coupling to the neuronal cell membrane allows very high signal-to-noise ratio recordings. In the light of an increasing demand for a stable, noninvasive and long-term recording at subthreshold resolution, a combination of vertical nanostraws with nanocavities is presented. These structures provide a spontaneous tight coupling with rat cortical neurons, resulting in high amplitude sensitivity and postsynaptic resolution capability, as directly confirmed by combined patch-clamp and microelectrode array measurements.
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Affiliation(s)
- Pegah Shokoohimehr
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
- Faculty 1, RWTH Aachen University, Templergraben 55, 52062, Aachen, Germany
| | - Bogdana Cepkenovic
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
- Faculty 1, RWTH Aachen University, Templergraben 55, 52062, Aachen, Germany
| | - Frano Milos
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
- Faculty 1, RWTH Aachen University, Templergraben 55, 52062, Aachen, Germany
| | - Justus Bednár
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
- Faculty 1, RWTH Aachen University, Templergraben 55, 52062, Aachen, Germany
| | - Hossein Hassani
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
- Faculty 1, RWTH Aachen University, Templergraben 55, 52062, Aachen, Germany
| | - Vanessa Maybeck
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
| | - Andreas Offenhäusser
- Institute of Biological Information Processing: Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße 1, 52428, Jülich, Germany
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Chang C, Furukawa T, Asahina T, Shimba K, Kotani K, Jimbo Y. Coupling of in vitro Neocortical-Hippocampal Coculture Bursts Induces Different Spike Rhythms in Individual Networks. Front Neurosci 2022; 16:873664. [PMID: 35677356 PMCID: PMC9168126 DOI: 10.3389/fnins.2022.873664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/15/2022] [Indexed: 11/21/2022] Open
Abstract
Brain-state alternation is important for long-term memory formation. Each brain state can be identified with a specific process in memory formation, e.g., encoding during wakefulness or consolidation during sleeping. The hippocampal-neocortical dialogue was proposed as a hypothetical framework for systems consolidation, which features different cross-frequency couplings between the hippocampus and distributed neocortical regions in different brain states. Despite evidence supporting this hypothesis, little has been reported about how information is processed with shifts in brain states. To address this gap, we developed an in vitro neocortical-hippocampal coculture model to study how activity coupling can affect connections between coupled networks. Neocortical and hippocampal neurons were cultured in two different compartments connected by a micro-tunnel structure. The network activity of the coculture model was recorded by microelectrode arrays underlying the substrate. Rhythmic bursting was observed in the spontaneous activity and electrical evoked responses. Rhythmic bursting activity in one compartment could couple to that in the other via axons passing through the micro-tunnels. Two types of coupling patterns were observed: slow-burst coupling (neocortex at 0.1–0.5 Hz and hippocampus at 1 Hz) and fast burst coupling (neocortex at 20–40 Hz and hippocampus at 4–10 Hz). The network activity showed greater synchronicity in the slow-burst coupling, as indicated by changes in the burstiness index. Network synchronicity analysis suggests the presence of different information processing states under different burst activity coupling patterns. Our results suggest that the hippocampal-neocortical coculture model possesses multiple modes of burst activity coupling between the cortical and hippocampal parts. With the addition of external stimulation, the neocortical-hippocampal network model we developed can elucidate the influence of state shifts on information processing.
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Affiliation(s)
- ChihHsiang Chang
- Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
- *Correspondence: ChihHsiang Chang
| | - Takuma Furukawa
- Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Takahiro Asahina
- Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Kenta Shimba
- Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Kiyoshi Kotani
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Yasuhiko Jimbo
- Department of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
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11
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Hu M, Frega M, Tolner EA, van den Maagdenberg AMJM, Frimat JP, le Feber J. MEA-ToolBox: an Open Source Toolbox for Standardized Analysis of Multi-Electrode Array Data. Neuroinformatics 2022; 20:1077-1092. [PMID: 35680724 PMCID: PMC9588481 DOI: 10.1007/s12021-022-09591-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2022] [Indexed: 12/31/2022]
Abstract
Functional assessment of in vitro neuronal networks-of relevance for disease modelling and drug testing-can be performed using multi-electrode array (MEA) technology. However, the handling and processing of the large amount of data typically generated in MEA experiments remains a huge hurdle for researchers. Various software packages have been developed to tackle this issue, but to date, most are either not accessible through the links provided by the authors or only tackle parts of the analysis. Here, we present ''MEA-ToolBox'', a free open-source general MEA analytical toolbox that uses a variety of literature-based algorithms to process the data, detect spikes from raw recordings, and extract information at both the single-channel and array-wide network level. MEA-ToolBox extracts information about spike trains, burst-related analysis and connectivity metrics without the need of manual intervention. MEA-ToolBox is tailored for comparing different sets of measurements and will analyze data from multiple recorded files placed in the same folder sequentially, thus considerably streamlining the analysis pipeline. MEA-ToolBox is available with a graphic user interface (GUI) thus eliminating the need for any coding expertise while offering functionality to inspect, explore and post-process the data. As proof-of-concept, MEA-ToolBox was tested on earlier-published MEA recordings from neuronal networks derived from human induced pluripotent stem cells (hiPSCs) obtained from healthy subjects and patients with neurodevelopmental disorders. Neuronal networks derived from patient's hiPSCs showed a clear phenotype compared to those from healthy subjects, demonstrating that the toolbox could extract useful parameters and assess differences between normal and diseased profiles.
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Affiliation(s)
- Michel Hu
- Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands ,Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Monica Frega
- Department of Clinical Neurophysiology, University of Twente, Enschede, the Netherlands
| | - Else A. Tolner
- Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands ,Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - A. M. J. M. van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands ,Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - J. P. Frimat
- Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands ,Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Joost le Feber
- Department of Clinical Neurophysiology, University of Twente, Enschede, the Netherlands
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12
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Pandanaboina SC, RanguMagar AB, Sharma KD, Chhetri BP, Parnell CM, Xie JY, Srivatsan M, Ghosh A. Functionalized Nanocellulose Drives Neural Stem Cells toward Neuronal Differentiation. J Funct Biomater 2021; 12:64. [PMID: 34842752 PMCID: PMC8628960 DOI: 10.3390/jfb12040064] [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: 10/04/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 11/23/2022] Open
Abstract
Transplantation of differentiated and fully functional neurons may be a better therapeutic option for the cure of neurodegenerative disorders and brain injuries than direct grafting of neural stem cells (NSCs) that are potentially tumorigenic. However, the differentiation of NSCs into a large population of neurons has been a challenge. Nanomaterials have been widely used as substrates to manipulate cell behavior due to their nano-size, excellent physicochemical properties, ease of synthesis, and versatility in surface functionalization. Nanomaterial-based scaffolds and synthetic polymers have been fabricated with topology resembling the micro-environment of the extracellular matrix. Nanocellulose materials are gaining attention because of their availability, biocompatibility, biodegradability and bioactivity, and affordable cost. We evaluated the role of nanocellulose with different linkage and surface features in promoting neuronal differentiation. Nanocellulose coupled with lysine molecules (CNC-Lys) provided positive charges that helped the cells to attach. Embryonic rat NSCs were differentiated on the CNC-Lys surface for up to three weeks. By the end of the three weeks of in vitro culture, 87% of the cells had attached to the CNC-Lys surface and more than half of the NSCs had differentiated into functional neurons, expressing endogenous glutamate, generating electrical activity and action potentials recorded by the multi-electrode array.
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Affiliation(s)
- Sahitya Chetan Pandanaboina
- Department of Biological Sciences and Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; (S.C.P.); (K.D.S.)
| | - Ambar B. RanguMagar
- Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR 72204, USA; (A.B.R.); (B.P.C.); (C.M.P.)
| | - Krishna D. Sharma
- Department of Biological Sciences and Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; (S.C.P.); (K.D.S.)
| | - Bijay P. Chhetri
- Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR 72204, USA; (A.B.R.); (B.P.C.); (C.M.P.)
| | - Charlette M. Parnell
- Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR 72204, USA; (A.B.R.); (B.P.C.); (C.M.P.)
| | - Jennifer Yanhua Xie
- Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine, Arkansas State University, Jonesboro, AR 72401, USA
| | - Malathi Srivatsan
- Department of Biological Sciences and Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; (S.C.P.); (K.D.S.)
| | - Anindya Ghosh
- Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR 72204, USA; (A.B.R.); (B.P.C.); (C.M.P.)
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13
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Ming Y, Abedin MJ, Tatic-Lucic S, Berdichevsky Y. Microdevice for directional axodendritic connectivity between micro 3D neuronal cultures. MICROSYSTEMS & NANOENGINEERING 2021; 7:67. [PMID: 34567779 PMCID: PMC8433170 DOI: 10.1038/s41378-021-00292-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/27/2021] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Neuronal cultures are widely used in neuroscience research. However, the randomness of circuits in conventional cultures prevents accurate in vitro modeling of cortical development and of the pathogenesis of neurological and psychiatric disorders. A basic feature of cortical circuits that is not captured in standard cultures of dissociated cortical cells is directional connectivity. In this work, a polydimethylsiloxane (PDMS)-based device that achieves directional connectivity between micro 3D cultures is demonstrated. The device consists of through-holes for micro three-dimensional (μ3D) clusters of cortical cells connected by microtrenches for axon and dendrite guidance. The design of the trenches relies in part on the concept of axonal edge guidance, as well as on the novel concept of specific dendrite targeting. This replicates dominant excitatory connectivity in the cortex, enables the guidance of the axon after it forms a synapse in passing (an "en passant" synapse), and ensures that directional selectivity is preserved over the lifetime of the culture. The directionality of connections was verified morphologically and functionally. Connections were dependent on glutamatergic synapses. The design of this device has the potential to serve as a building block for the reconstruction of more complex cortical circuits in vitro.
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Affiliation(s)
- Yixuan Ming
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA USA
| | - Md Joynal Abedin
- Department of Bioengineering, Lehigh University, Bethlehem, PA USA
| | - Svetlana Tatic-Lucic
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA USA
- Department of Bioengineering, Lehigh University, Bethlehem, PA USA
| | - Yevgeny Berdichevsky
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA USA
- Department of Bioengineering, Lehigh University, Bethlehem, PA USA
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14
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Sherrill SP, Timme NM, Beggs JM, Newman EL. Partial information decomposition reveals that synergistic neural integration is greater downstream of recurrent information flow in organotypic cortical cultures. PLoS Comput Biol 2021; 17:e1009196. [PMID: 34252081 PMCID: PMC8297941 DOI: 10.1371/journal.pcbi.1009196] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/22/2021] [Accepted: 06/18/2021] [Indexed: 11/22/2022] Open
Abstract
The directionality of network information flow dictates how networks process information. A central component of information processing in both biological and artificial neural networks is their ability to perform synergistic integration–a type of computation. We established previously that synergistic integration varies directly with the strength of feedforward information flow. However, the relationships between both recurrent and feedback information flow and synergistic integration remain unknown. To address this, we analyzed the spiking activity of hundreds of neurons in organotypic cultures of mouse cortex. We asked how empirically observed synergistic integration–determined from partial information decomposition–varied with local functional network structure that was categorized into motifs with varying recurrent and feedback information flow. We found that synergistic integration was elevated in motifs with greater recurrent information flow beyond that expected from the local feedforward information flow. Feedback information flow was interrelated with feedforward information flow and was associated with decreased synergistic integration. Our results indicate that synergistic integration is distinctly influenced by the directionality of local information flow. Networks compute information. That is, they modify inputs to generate distinct outputs. These computations are an important component of network information processing. Knowing how the routing of information in a network influences computation is therefore crucial. Here we asked how a key form of computation—synergistic integration—is related to the direction of local information flow in networks of spiking cortical neurons. Specifically, we asked how information flow between input neurons (i.e., recurrent information flow) and information flow from output neurons to input neurons (i.e., feedback information flow) was related to the amount of synergistic integration performed by output neurons. We found that greater synergistic integration occurred where there was more recurrent information flow. And, lesser synergistic integration occurred where there was more feedback information flow relative to feedforward information flow. These results show that computation, in the form of synergistic integration, is distinctly influenced by the directionality of local information flow. Such work is valuable for predicting where and how network computation occurs and for designing networks with desired computational abilities.
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Affiliation(s)
- Samantha P. Sherrill
- Department of Psychological and Brain Sciences & Program in Neuroscience, Indiana University Bloomington, Bloomington, Indiana, United States of America
- * E-mail: (SPS); (ELN)
| | - Nicholas M. Timme
- Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - John M. Beggs
- Department of Physics & Program in Neuroscience, Indiana University Bloomington, Bloomington, Indiana, United States of America
| | - Ehren L. Newman
- Department of Psychological and Brain Sciences & Program in Neuroscience, Indiana University Bloomington, Bloomington, Indiana, United States of America
- * E-mail: (SPS); (ELN)
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15
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Dias I, Levers MR, Lamberti M, Hassink GC, van Wezel R, le Feber J. Consolidation of memory traces in cultured cortical networks requires low cholinergic tone, synchronized activity and high network excitability. J Neural Eng 2021; 18. [PMID: 33892486 DOI: 10.1088/1741-2552/abfb3f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/23/2021] [Indexed: 11/11/2022]
Abstract
In systems consolidation, encoded memories are replayed by the hippocampus during slow-wave sleep (SWS), and permanently stored in the neocortex. Declarative memory consolidation is believed to benefit from the oscillatory rhythms and low cholinergic tone observed in this sleep stage, but underlying mechanisms remain unclear. To clarify the role of cholinergic modulation and synchronized activity in memory consolidation, we applied repeated electrical stimulation in mature cultures of dissociated rat cortical neurons with high or low cholinergic tone, mimicking the cue replay observed during systems consolidation under distinct cholinergic concentrations. In the absence of cholinergic input, these cultures display activity patterns hallmarked by network bursts, synchronized events reminiscent of the low frequency oscillations observed during SWS. They display stable activity and connectivity, which mutually interact and achieve an equilibrium. Electrical stimulation reforms the equilibrium to include the stimulus response, a phenomenon interpreted as memory trace formation. Without cholinergic input, activity was burst-dominated. First application of a stimulus induced significant connectivity changes, while subsequent repetition no longer affected connectivity. Presenting a second stimulus at a different electrode had the same effect, whereas returning to the initial stimuli did not induce further connectivity alterations, indicating that the second stimulus did not erase the 'memory trace' of the first. Distinctively, cultures with high cholinergic tone displayed reduced network excitability and dispersed firing, and electrical stimulation did not induce significant connectivity changes. We conclude that low cholinergic tone facilitates memory formation and consolidation, possibly through enhanced network excitability. Network bursts or SWS oscillations may merely reflect high network excitability.
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Affiliation(s)
- Inês Dias
- Department of Clinical Neurophysiology, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands
| | - Marloes R Levers
- Department of Clinical Neurophysiology, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands
| | - Martina Lamberti
- Department of Clinical Neurophysiology, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands
| | - Gerco C Hassink
- Department of Clinical Neurophysiology, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands
| | - Richard van Wezel
- Department of Biomedical Signals and Systems, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands.,Department of Biophysics, Radboud University, Nijmegen, PO Box 9010 6525AJ, The Netherlands
| | - Joost le Feber
- Department of Clinical Neurophysiology, University of Twente, Enschede, PO Box 217 7500AE, The Netherlands
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16
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Herzog N, Johnstone A, Bellamy T, Russell N. Characterization of neuronal viability and network activity under microfluidic flow. J Neurosci Methods 2021; 358:109200. [PMID: 33932456 DOI: 10.1016/j.jneumeth.2021.109200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 04/06/2021] [Accepted: 04/22/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Microfluidics technology has the potential to allow precise control of the temporal and spatial aspects of solute concentration, making it highly relevant for the study of volume transmission mechanisms in neural tissue. However, full utilization of this technology depends on understanding how microfluidic flow at the rates needed for rapid solution exchange affects neuronal viability and network activity. NEW METHOD We designed a tape-based pressurized microfluidic flow system that is simple to fabricate and can be attached to commercial microelectrode arrays. The device is multi-layered, allowing the inclusion of a porous polycarbonate membrane to isolate neuronal cultures from shear forces while maintaining diffusive exchange of solutes. We used this system to investigate how flow affected survival and spiking patterns of cultured hippocampal neurons. RESULTS Viability and network activity of the cultures were reduced in proportion to flow rate. However, shear reduction measures did not improve survival or spiking activity; media conditioning in conjunction with culture age proved to be the critical factors for network stability. Diffusion simulations indicate that dilution of a small molecule accounts for the deleterious effects of flow on neuronal cultures. COMPARISON WITH EXISTING METHODS This work establishes the experimental conditions for real time measurement of network activity during rapid solution exchange, using multi-layered chambers with reversible bonding that allow for reuse of microelectrode arrays. CONCLUSIONS With correct media conditioning, the microfluidic flow system allows drug delivery on a subsecond timescale without disruption of network activity or viability, enabling in vitro reproduction of volume transmission mechanisms.
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Affiliation(s)
- Nitzan Herzog
- School of Electronic and Electrical Engineering, University of Nottingham, Nottingham, United Kingdom.
| | - Alexander Johnstone
- School of Electronic and Electrical Engineering, University of Nottingham, Nottingham, United Kingdom.
| | - Tomas Bellamy
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
| | - Noah Russell
- School of Electronic and Electrical Engineering, University of Nottingham, Nottingham, United Kingdom.
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17
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Domínguez HJ, Cabrera-García D, Cuadrado C, Novelli A, Fernández-Sánchez MT, Fernández JJ, Daranas AH. Prorocentroic Acid, a Neuroactive Super-Carbon-Chain Compound from the Dinoflagellate Prorocentrum hoffmannianum. Org Lett 2020; 23:13-18. [DOI: 10.1021/acs.orglett.0c03437] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Humberto J. Domínguez
- Instituto Universitario de Bio-Orgánica Antonio González, University of La Laguna, 38206, Tenerife, Spain
| | - David Cabrera-García
- Department of Biochemistry and Molecular Biology and University Institute of Biotechnology of Asturias (IUBA), Campus “El Cristo”, University of Oviedo, 33006 Oviedo, Oviedo, Spain
| | - Cristina Cuadrado
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas (IPNA-CSIC), La Laguna, 38206, Tenerife, Spain
| | - Antonello Novelli
- Department of Psychology and University Institute of Biotechnology of Asturias (IUBA), Campus “El Cristo”, University of Oviedo; Institute for Sanitary Research of the Princedom of Asturias (ISPA), 33006 Oviedo, Oviedo, Spain
| | - M. Teresa Fernández-Sánchez
- Department of Biochemistry and Molecular Biology and University Institute of Biotechnology of Asturias (IUBA), Campus “El Cristo”, University of Oviedo, 33006 Oviedo, Oviedo, Spain
| | - José J. Fernández
- Instituto Universitario de Bio-Orgánica Antonio González, University of La Laguna, 38206, Tenerife, Spain
| | - Antonio Hernández Daranas
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas (IPNA-CSIC), La Laguna, 38206, Tenerife, Spain
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18
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Ming Y, Hasan MF, Tatic-Lucic S, Berdichevsky Y. Micro Three-Dimensional Neuronal Cultures Generate Developing Cortex-Like Activity Patterns. Front Neurosci 2020; 14:563905. [PMID: 33122989 PMCID: PMC7573570 DOI: 10.3389/fnins.2020.563905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022] Open
Abstract
Studies aimed at neurological drug discovery have been carried out both in vitro and in vivo. In vitro cell culture models have showed potential as drug testing platforms characterized by high throughput, low cost, good reproducibility and ease of handling and observation. However, in vitro neuronal culture models are facing challenges in replicating in vivo-like activity patterns. This work reports an in vitro culture technique that is capable of producing micro three-dimensional (μ3D) cultures of only a few tens of neurons. The μ3D cultures generated by this method were uniform in size and density of neurons. These μ3D cultures had complex spontaneous synchronized neuronal activity patterns which were similar to those observed in the developing cortex and in much larger 3D cultures, but not in 2D cultures. Bursts could be reliably evoked by stimulation of single neurons. Synchronized bursts in μ3D cultures were abolished by inhibitors of glutamate receptors, while inhibitors of GABAA receptors had a more complex effect. This pharmacological profile is similar to bursts in neonatal cortex. Since large numbers of reproducible μ3D cultures can be created and observed in parallel, this model of the developing cortex may find applications in high-throughput drug discovery experiments.
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Affiliation(s)
- Yixuan Ming
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA, United States
| | - Md Fayad Hasan
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA, United States
| | - Svetlana Tatic-Lucic
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA, United States.,Department of Bioengineering, Lehigh University, Bethlehem, PA, United States
| | - Yevgeny Berdichevsky
- Department of Electrical & Computer Engineering, Lehigh University, Bethlehem, PA, United States.,Department of Bioengineering, Lehigh University, Bethlehem, PA, United States
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19
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Brofiga M, Pisano M, Tedesco M, Raiteri R, Massobrio P. Three-dimensionality shapes the dynamics of cortical interconnected to hippocampal networks. J Neural Eng 2020; 17:056044. [DOI: 10.1088/1741-2552/abc023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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20
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Minoshima W, Masui K, Tani T, Nawa Y, Fujita S, Ishitobi H, Hosokawa C, Inouye Y. Deuterated Glutamate-Mediated Neuronal Activity on Micro-Electrode Arrays. MICROMACHINES 2020; 11:mi11090830. [PMID: 32878218 PMCID: PMC7569784 DOI: 10.3390/mi11090830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/21/2020] [Accepted: 08/28/2020] [Indexed: 11/16/2022]
Abstract
The excitatory synaptic transmission is mediated by glutamate in neuronal networks of the mammalian brain. In addition to the synaptic glutamate, extra-synaptic glutamate is known to modulate the neuronal activity. In neuronal networks, glutamate uptake is an important role of neurons and glial cells for lowering the concentration of extracellular glutamate and to avoid the excitotoxicity by glutamate. Monitoring the spatial distribution of intracellular glutamate is important to study the uptake of glutamate, but the approach has been hampered by the absence of appropriate glutamate analogs that report the localization of glutamate. Deuterium-labeled glutamate (GLU-D) is a promising tracer for monitoring the intracellular concentration of glutamate, but physiological properties of GLU-D have not been studied. Here we study the effects of extracellular GLU-D for the neuronal activity by using primary cultured rat hippocampal neurons that form neuronal networks on microelectrodes array. The frequency of firing in the spontaneous activity of neurons increased with the increasing concentration of extracellular GLU-D. The frequency of synchronized burst activity in neurons increased similarly as we observed in the spontaneous activity. These changes of the neuronal activity with extracellular GLU-D were suppressed by antagonists of glutamate receptors. These results suggest that GLU-D can be used as an analog of glutamate with equivalent effects for facilitating the neuronal activity. We anticipate GLU-D developing as a promising analog of glutamate for studying the dynamics of glutamate during neuronal activity.
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Affiliation(s)
- Wataru Minoshima
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
| | - Kyoko Masui
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
| | - Tomomi Tani
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda 563-0026, Japan;
| | - Yasunori Nawa
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Department of Applied Physics, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
| | - Satoshi Fujita
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda 563-0026, Japan;
- Department of Applied Physics, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
| | - Hidekazu Ishitobi
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
- Department of Applied Physics, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
| | - Chie Hosokawa
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Department of Chemistry, Division of Molecular Materials Science, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
- Correspondence: (C.H.); (Y.I.); Tel.: +81-6-6605-3700 (C.H.); +81-6-6879-4615 (Y.I.)
| | - Yasushi Inouye
- AIST–Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, AIST, Osaka 565-0871, Japan; (W.M.); (K.M.); (Y.N.); (S.F.); (H.I.)
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
- Department of Applied Physics, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
- Correspondence: (C.H.); (Y.I.); Tel.: +81-6-6605-3700 (C.H.); +81-6-6879-4615 (Y.I.)
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21
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Presynaptic L-Type Ca 2+ Channels Increase Glutamate Release Probability and Excitatory Strength in the Hippocampus during Chronic Neuroinflammation. J Neurosci 2020; 40:6825-6841. [PMID: 32747440 DOI: 10.1523/jneurosci.2981-19.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/18/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation is involved in the pathogenesis of several neurologic disorders, including epilepsy. Both changes in the input/output functions of synaptic circuits and cell Ca2+ dysregulation participate in neuroinflammation, but their impact on neuron function in epilepsy is still poorly understood. Lipopolysaccharide (LPS), a toxic byproduct of bacterial lysis, has been extensively used to stimulate inflammatory responses both in vivo and in vitro LPS stimulates Toll-like receptor 4, an important mediator of the brain innate immune response that contributes to neuroinflammation processes. Although we report that Toll-like receptor 4 is expressed in both excitatory and inhibitory mouse hippocampal neurons (both sexes), its chronic stimulation by LPS induces a selective increase in the excitatory synaptic strength, characterized by enhanced synchronous and asynchronous glutamate release mechanisms. This effect is accompanied by a change in short-term plasticity with decreased facilitation, decreased post-tetanic potentiation, and increased depression. Quantal analysis demonstrated that the effects of LPS on excitatory transmission are attributable to an increase in the probability of release associated with an overall increased expression of L-type voltage-gated Ca2+ channels that, at presynaptic terminals, abnormally contributes to evoked glutamate release. Overall, these changes contribute to the excitatory/inhibitory imbalance that scales up neuronal network activity under inflammatory conditions. These results provide new molecular clues for treating hyperexcitability of hippocampal circuits associated with neuroinflammation in epilepsy and other neurologic disorders.SIGNIFICANCE STATEMENT Neuroinflammation is thought to have a pathogenetic role in epilepsy, a disorder characterized by an imbalance between excitation/inhibition. Fine adjustment of network excitability and regulation of synaptic strength are both implicated in the homeostatic maintenance of physiological levels of neuronal activity. Here, we focused on the effects of chronic neuroinflammation induced by lipopolysaccharides on hippocampal glutamatergic and GABAergic synaptic transmission. Our results show that, on chronic stimulation with lipopolysaccharides, glutamatergic, but not GABAergic, neurons exhibit an enhanced synaptic strength and changes in short-term plasticity because of an increased glutamate release that results from an anomalous contribution of L-type Ca2+ channels to neurotransmitter release.
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Bikbaev A, Ciuraszkiewicz-Wojciech A, Heck J, Klatt O, Freund R, Mitlöhner J, Enrile Lacalle S, Sun M, Repetto D, Frischknecht R, Ablinger C, Rohlmann A, Missler M, Obermair GJ, Di Biase V, Heine M. Auxiliary α2δ1 and α2δ3 Subunits of Calcium Channels Drive Excitatory and Inhibitory Neuronal Network Development. J Neurosci 2020; 40:4824-4841. [PMID: 32414783 PMCID: PMC7326358 DOI: 10.1523/jneurosci.1707-19.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 03/31/2020] [Accepted: 05/09/2020] [Indexed: 01/21/2023] Open
Abstract
VGCCs are multisubunit complexes that play a crucial role in neuronal signaling. Auxiliary α2δ subunits of VGCCs modulate trafficking and biophysical properties of the pore-forming α1 subunit and trigger excitatory synaptogenesis. Alterations in the expression level of α2δ subunits were implicated in several syndromes and diseases, including chronic neuropathic pain, autism, and epilepsy. However, the contribution of distinct α2δ subunits to excitatory/inhibitory imbalance and aberrant network connectivity characteristic for these pathologic conditions remains unclear. Here, we show that α2δ1 overexpression enhances spontaneous neuronal network activity in developing and mature cultures of hippocampal neurons. In contrast, overexpression, but not downregulation, of α2δ3 enhances neuronal firing in immature cultures, whereas later in development it suppresses neuronal activity. We found that α2δ1 overexpression increases excitatory synaptic density and selectively enhances presynaptic glutamate release, which is impaired on α2δ1 knockdown. Overexpression of α2δ3 increases the excitatory synaptic density as well but also facilitates spontaneous GABA release and triggers an increase in the density of inhibitory synapses, which is accompanied by enhanced axonaloutgrowth in immature interneurons. Together, our findings demonstrate that α2δ1 and α2δ3 subunits play distinct but complementary roles in driving formation of structural and functional network connectivity during early development. An alteration in α2δ surface expression during critical developmental windows can therefore play a causal role and have a profound impact on the excitatory-to-inhibitory balance and network connectivity.SIGNIFICANCE STATEMENT The computational capacity of neuronal networks is determined by their connectivity. Chemical synapses are the main interface for transfer of information between individual neurons. The initial formation of network connectivity requires spontaneous electrical activity and the calcium channel-mediated signaling. We found that, in early development, auxiliary α2δ3 subunits of calcium channels foster presynaptic release of GABA, trigger formation of inhibitory synapses, and promote axonal outgrowth in inhibitory interneurons. In contrast, later in development, α2δ1 subunits promote the glutamatergic neurotransmission and synaptogenesis, as well as strongly enhance neuronal network activity. We propose that formation of connectivity in neuronal networks is associated with a concerted interplay of α2δ1 and α2δ3 subunits of calcium channels.
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Affiliation(s)
- Arthur Bikbaev
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Anna Ciuraszkiewicz-Wojciech
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, 39106, Germany
| | - Jennifer Heck
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Oliver Klatt
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Romy Freund
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Jessica Mitlöhner
- RG Brain Extracellular Matrix, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Sara Enrile Lacalle
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Miao Sun
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Daniele Repetto
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Renato Frischknecht
- RG Brain Extracellular Matrix, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
- Department of Biology, Animal Physiology, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, Innsbruck, 6020, Austria
| | - Astrid Rohlmann
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Markus Missler
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Gerald J Obermair
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems, 3500, Austria
| | - Valentina Di Biase
- Institute of Molecular and Clinical Pharmacology, Medical University Innsbruck, Innsbruck, 6020, Austria
| | - Martin Heine
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, 39106, Germany
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Manzati M, Sorbo T, Giugliano M, Ballerini L. Foetal neural progenitors contribute to postnatal circuits formation ex vivo: an electrophysiological investigation. Mol Brain 2020; 13:78. [PMID: 32430072 PMCID: PMC7236481 DOI: 10.1186/s13041-020-00619-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/08/2020] [Indexed: 11/10/2022] Open
Abstract
Neuronal progenitor cells (NPC) play an essential role in homeostasis of the central nervous system (CNS). Considering their ability to differentiate into specific lineages, their manipulation and control could have a major therapeutic impact for those CNS injuries or degenerative diseases characterized by neuronal cell loss. In this work, we established an in vitro co-culture and tested the ability of foetal NPC (fNPC) to integrate among post-mitotic hippocampal neurons and contribute to the electrical activity of the resulting networks. We performed extracellular electrophysiological recordings of the activity of neuronal networks and compared the properties of spontaneous spiking in hippocampal control cultures (HCC), fNPC, and mixed circuitries ex vivo. We further employed patch-clamp intracellular recordings to examine single-cell excitability. We report of the capability of fNPC to mature when combined to hippocampal neurons, shaping the profile of network activity, a result suggestive of newly formed connectivity ex vivo.
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Affiliation(s)
- Matteo Manzati
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, I-34136, Trieste, Italy.,Neuronal Dynamics Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, I-34136, Trieste, Italy
| | - Teresa Sorbo
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, I-34136, Trieste, Italy
| | - Michele Giugliano
- Neuronal Dynamics Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, I-34136, Trieste, Italy. .,Department of Biomedical Sciences and Institute Born-Bunge, Universiteit Antwerpen, B-2610, Wilrijk, Belgium.
| | - Laura Ballerini
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, I-34136, Trieste, Italy.
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24
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Pace M, Colombi I, Falappa M, Freschi A, Bandarabadi M, Armirotti A, Encarnación BM, Adamantidis AR, Amici R, Cerri M, Chiappalone M, Tucci V. Loss of Snord116 alters cortical neuronal activity in mice: a preclinical investigation of Prader–Willi syndrome. Hum Mol Genet 2020; 29:2051-2064. [DOI: 10.1093/hmg/ddaa084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022] Open
Abstract
Abstract
Prader–Willi syndrome (PWS) is a neurodevelopmental disorder that is characterized by metabolic alteration and sleep abnormalities mostly related to rapid eye movement (REM) sleep disturbances. The disease is caused by genomic imprinting defects that are inherited through the paternal line. Among the genes located in the PWS region on chromosome 15 (15q11-q13), small nucleolar RNA 116 (Snord116) has been previously associated with intrusions of REM sleep into wakefulness in humans and mice. Here, we further explore sleep regulation of PWS by reporting a study with PWScrm+/p− mouse line, which carries a paternal deletion of Snord116. We focused our study on both macrostructural electrophysiological components of sleep, distributed among REMs and nonrapid eye movements. Of note, here, we study a novel electroencephalography (EEG) graphoelements of sleep for mouse studies, the well-known spindles. EEG biomarkers are often linked to the functional properties of cortical neurons and can be instrumental in translational studies. Thus, to better understand specific properties, we isolated and characterized the intrinsic activity of cortical neurons using in vitro microelectrode array. Our results confirm that the loss of Snord116 gene in mice influences specific properties of REM sleep, such as theta rhythms and, for the first time, the organization of REM episodes throughout sleep–wake cycles. Moreover, the analysis of sleep spindles present novel specific phenotype in PWS mice, indicating that a new catalog of sleep biomarkers can be informative in preclinical studies of PWS.
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Affiliation(s)
- Marta Pace
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Ilaria Colombi
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università degli Studi di Genova, Genova 16132, Italy
| | - Matteo Falappa
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università degli Studi di Genova, Genova 16132, Italy
| | - Andrea Freschi
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Mojtaba Bandarabadi
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
| | - Andrea Armirotti
- Analytical Chemistry Facility, Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | | | - Antoine R Adamantidis
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
- Department of Clinical Research, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
| | - Roberto Amici
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum—University of Bologna, Bologna 40126, Italy
| | - Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum—University of Bologna, Bologna 40126, Italy
| | - Michela Chiappalone
- Rehab Technologies, Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Valter Tucci
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
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25
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Familiarity Detection and Memory Consolidation in Cortical Assemblies. eNeuro 2020; 7:ENEURO.0006-19.2020. [PMID: 32122957 PMCID: PMC7215585 DOI: 10.1523/eneuro.0006-19.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/30/2020] [Accepted: 02/20/2020] [Indexed: 01/12/2023] Open
Abstract
Humans have a large capacity of recognition memory (Dudai, 1997), a fundamental property of higher-order brain functions such as abstraction and generalization (Vogt and Magnussen, 2007). Familiarity is the first step towards recognition memory. We have previously demonstrated using unsupervised neural network simulations that familiarity detection of complex patterns emerges in generic cortical microcircuits with bidirectional synaptic plasticity. It is therefore meaningful to conduct similar experiments on biological neuronal networks to validate these results. Studies of learning and memory in dissociated rodent neuronal cultures remain inconclusive to date. Synchronized network bursts (SNBs) that occur spontaneously and periodically have been speculated to be an intervening factor. By optogenetically stimulating cultured cortical networks with random dot movies (RDMs), we were able to reduce the occurrence of SNBs, after which an ability for familiarity detection emerged: previously seen patterns elicited higher firing rates than novel ones. Differences in firing rate were distributed over the entire network, suggesting that familiarity detection is a system level property. We also studied the change in SNB patterns following familiarity encoding. Support vector machine (SVM) classification results indicate that SNBs may be facilitating memory consolidation of the learned pattern. In addition, using a novel network connectivity probing method, we were able to trace the change in synaptic efficacy induced by familiarity encoding, providing insights on the long-term impact of having SNBs in the cultures.
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26
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Eidum DM, Henriquez CS. Modeling the effects of sinusoidal stimulation and synaptic plasticity on linked neural oscillators. CHAOS (WOODBURY, N.Y.) 2020; 30:033105. [PMID: 32237786 DOI: 10.1063/1.5126104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/13/2020] [Indexed: 06/11/2023]
Abstract
The brain exhibits intrinsic oscillatory behavior, which plays a vital role in communication and information processing. Abnormalities in brain rhythms have been linked to numerous disorders, including depression and schizophrenia. Rhythmic electrical stimulation (e.g., transcranial magnetic stimulation and transcranial alternating current stimulation) has been used to modulate these oscillations and produce lasting changes in neural activity. In this computational study, we investigate the combined effects of sinusoidal stimulation and synaptic plasticity on model networks comprised of simple, tunable four-neuron oscillators. While not intended to model a specific brain circuit, this idealization was created to provide some intuition on how electrical modulation can induce plastic changes in the oscillatory state. Linked pairs of oscillators were stimulated with sinusoidal current, and their behavior was measured as a function of their intrinsic frequencies, inter-oscillator synaptic strengths, and stimulus strength and frequency. Under certain stimulus conditions, sinusoidal current can disrupt the network's natural firing patterns. Synaptic plasticity can induce weight imbalances that permanently change the characteristic firing behavior of the network. Grids of 100 oscillators with random frequencies were also subjected to a wide array of stimulus conditions. The characteristics of the post-stimulus network activity depend heavily on the stimulus frequency and amplitude as well as the initial strength of inter-oscillator connections. Synchronization arises at the network level from complex patterns of activity propagation, which are enhanced or disrupted by different stimuli. The findings may prove important to the design of novel neuromodulation treatments and techniques seeking to affect oscillatory activity in the brain.
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Affiliation(s)
- Derek M Eidum
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Craig S Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
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27
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Minoshima W, Hosokawa C, Kudoh SN, Tawa K. Real-time fluorescence measurement of spontaneous activity in a high-density hippocampal network cultivated on a plasmonic dish. J Chem Phys 2020; 152:014706. [PMID: 31914750 DOI: 10.1063/1.5131497] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-density cultured neuronal networks have been used to evaluate synchronized features of neuronal populations. Voltage-sensitive dye (VSD) imaging of a dissociated cultured neuronal network is a critical method for studying synchronized neuronal activity in single cells. However, the signals of VSD are generally too faint-that is, the signal-to-noise ratio (S/N) is too low-to detect neuronal activity. In our previous research, a silver (Ag) plasmonic chip enhanced the fluorescence intensity of VSD to detect spontaneous neural spikes on VSD imaging. However, no high-density network was cultivated on the Ag plasmonic chip, perhaps because of the chemical instability of the Ag surface. In this study, to overcome the instability of the chip, we used a chemically stable gold (Au) plasmonic dish, which was a plastic dish with a plasmonic chip pasted to the bottom, to observe neuronal activity in a high-density neuronal network. We expected that the S/N in real-time VSD imaging of the Au plasmonic chip would be improved compared to that of a conventional glass-bottomed dish, and we also expected to detect frequent neural spikes. The increase in the number of spikes when inhibitory neurotransmitter receptors were inhibited suggests that the spikes corresponded to neural activity. Therefore, real-time VSD imaging of an Au plasmonic dish was effective for measuring spontaneous network activity in a high-density neuronal network at the spatial resolution of a single cell.
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Affiliation(s)
- Wataru Minoshima
- School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
| | - Chie Hosokawa
- School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
| | - Suguru N Kudoh
- School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
| | - Keiko Tawa
- School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
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28
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Long-term real-time imaging of a voltage sensitive dye in cultured hippocampal neurons using the silver plasmonic dish. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.111949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Teppola H, Aćimović J, Linne ML. Unique Features of Network Bursts Emerge From the Complex Interplay of Excitatory and Inhibitory Receptors in Rat Neocortical Networks. Front Cell Neurosci 2019; 13:377. [PMID: 31555093 PMCID: PMC6742722 DOI: 10.3389/fncel.2019.00377] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 08/02/2019] [Indexed: 12/20/2022] Open
Abstract
Spontaneous network activity plays a fundamental role in the formation of functional networks during early development. The landmark of this activity is the recurrent emergence of intensive time-limited network bursts (NBs) rapidly spreading across the entire dissociated culture in vitro. The main excitatory mediators of NBs are glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and N-Methyl-D-aspartic-acid receptors (NMDARs) that express fast and slow ion channel kinetics, respectively. The fast inhibition of the activity is mediated through gamma-aminobutyric acid type A receptors (GABAARs). Although the AMPAR, NMDAR and GABAAR kinetics have been biophysically characterized in detail at the monosynaptic level in a variety of brain areas, the unique features of NBs emerging from the kinetics and the complex interplay of these receptors are not well understood. The goal of this study is to analyze the contribution of fast GABAARs on AMPAR- and NMDAR- mediated spontaneous NB activity in dissociated neonatal rat cortical cultures at 3 weeks in vitro. The networks were probed by both acute and gradual application of each excitatory receptor antagonist and combinations of acute excitatory and inhibitory receptor antagonists. At the same time, the extracellular network-wide activity was recorded with microelectrode arrays (MEAs). We analyzed the characteristic NB measures extracted from NB rate profiles and the distributions of interspike intervals, interburst intervals, and electrode recruitment time as well as the similarity of spatio-temporal patterns of network activity under different receptor antagonists. We show that NBs were rapidly initiated and recruited as well as diversely propagated by AMPARs and temporally and spatially maintained by NMDARs. GABAARs reduced the spiking frequency in AMPAR-mediated networks and dampened the termination of NBs in NMDAR-mediated networks as well as slowed down the recruitment of activity in all networks. Finally, we show characteristic super bursts composed of slow NBs with highly repetitive spatio-temporal patterns in gradually AMPAR blocked networks. To the best of our knowledge, this study is the first to unravel in detail how the three main mediators of synaptic transmission uniquely shape the NB characteristics, such as the initiation, maintenance, recruitment and termination of NBs in cortical cell cultures in vitro.
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Affiliation(s)
- Heidi Teppola
- Computational Neuroscience Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jugoslava Aćimović
- Computational Neuroscience Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Marja-Leena Linne
- Computational Neuroscience Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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30
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Shimba K, Sakai K, Iida S, Kotani K, Jimbo Y. Long-Term Developmental Process of the Human Cortex Revealed In Vitro by Axon-Targeted Recording Using a Microtunnel-Augmented Microelectrode Array. IEEE Trans Biomed Eng 2019; 66:2538-2545. [DOI: 10.1109/tbme.2019.2891310] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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31
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Active High-Density Electrode Arrays: Technology and Applications in Neuronal Cell Cultures. ADVANCES IN NEUROBIOLOGY 2019. [PMID: 31073940 DOI: 10.1007/978-3-030-11135-9_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Active high-density electrode arrays realized with complementary metal-oxide-semiconductor (CMOS) technology provide electrophysiological recordings from several thousands of closely spaced microelectrodes. This has drastically advanced the spatiotemporal recording resolution of conventional multielectrode arrays (MEAs). Thus, today's electrophysiology in neuronal cultures can exploit label-free electrical readouts from a large number of single neurons within the same network. This provides advanced capabilities to investigate the properties of self-assembling neuronal networks, to advance studies on neurotoxicity and neurodevelopmental alterations associated with human brain diseases, and to develop cell culture models for testing drug- or cell-based strategies for therapies.Here, after introducing the reader to this neurotechnology, we summarize the results of different recent studies demonstrating the potential of active high-density electrode arrays for experimental applications. We also discuss ongoing and possible future research directions that might allow for moving these platforms forward for screening applications.
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32
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Hasan MF, Ghiasvand S, Wang H, Miwa JM, Berdichevsky Y. Neural layer self-assembly in geometrically confined rat and human 3D cultures. Biofabrication 2019; 11:045011. [PMID: 31247598 DOI: 10.1088/1758-5090/ab2d3f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neurological disorders affect millions of Americans and this number is expected to rise with the aging population. Development of drugs to treat these disorders may be facilitated by improved in vitro models that faithfully reproduce salient features of the relevant brain regions. Current 3D culture methods face challenges with reliably reproducing microarchitectural features of brain morphology such as cortical or hippocampal layers. In this work, polydimethylsiloxane (PDMS) mini-wells were used to create low aspect ratio, adherent 3D constructs where neurons self-assemble into layers. Layer self-assembly was determined to depend on the size of the PDMS mini-well. Layer formation occurred in cultures composed of primary rat cortical neurons or human induced pluripotent stem cell-derived neurons and astrocytes and was robust and reproducible. Layered 3D constructs were found to have spontaneous neural activity characterized by long bursts similar to activity in the developing cortex. The responses of layered 3D cultures to drugs were more similar to in vivo data than those of 2D cultures. 3D constructs created with this method may be thus suitable as in vitro models for drug discovery for neurological disorders.
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Affiliation(s)
- Md Fayad Hasan
- Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015, United States of America
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Vo HT, Phillips ML, Herskowitz JH, King GD. Klotho deficiency affects the spine morphology and network synchronization of neurons. Mol Cell Neurosci 2019; 98:1-11. [PMID: 30991103 PMCID: PMC6613977 DOI: 10.1016/j.mcn.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/25/2019] [Accepted: 04/09/2019] [Indexed: 01/01/2023] Open
Abstract
Klotho-deficient mice rapidly develop cognitive impairment and show some evidence of the onset of neurodegeneration. However, it is impossible to investigate the long-term consequences on the brain because of the dramatic shortening of lifespan caused by systemic klotho deficiency. As klotho expression is downregulated with advancing organismal age, understanding the mechanisms of klotho action is important for developing novel strategies to support healthy brain aging. Previously, we reported that klotho-deficient mice show enhanced long-term potentiation prior to the onset of cognitive impairment. To inform this unusual phenotype, herein, we examined neuronal structure and in vitro synaptic function. Our results indicate that klotho deficiency causes the population of dendritic spines to shift towards increased head diameter and decreased length consistent with mature, mushroom type spines. Multi-electrode array recordings from klotho-deficient neurons show increased synchronous firing and activity changes reflective of increased neuronal network activity. Supplementation of the neuronal growth media with recombinant shed klotho corrected some but not all of the activity changes caused by klotho deficiency. Last, in vivo we found that klotho-deficient mice have a decreased latency to induced seizure activity. Together these data show that klotho-deficient memory impairments are underpinned by structural and functional changes that may preclude ongoing normal cognition.
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Affiliation(s)
- Hai T Vo
- Department of Neurobiology, University of Alabama at Birmingham, 1825 University Blvd. Shelby 913, Birmingham 35294, AL, USA
| | - Mary L Phillips
- Department of Neurobiology, University of Alabama at Birmingham, 1825 University Blvd. Shelby 913, Birmingham 35294, AL, USA
| | - Jeremy H Herskowitz
- Department of Neurology, University of Alabama at Birmingham, 1825 University Blvd. Shelby 1114, Birmingham 35294, AL, USA
| | - Gwendalyn D King
- Department of Neurobiology, University of Alabama at Birmingham, 1825 University Blvd. Shelby 913, Birmingham 35294, AL, USA.
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34
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Lam D, Enright HA, Cadena J, Peters SKG, Sales AP, Osburn JJ, Soscia DA, Kulp KS, Wheeler EK, Fischer NO. Tissue-specific extracellular matrix accelerates the formation of neural networks and communities in a neuron-glia co-culture on a multi-electrode array. Sci Rep 2019; 9:4159. [PMID: 30858401 PMCID: PMC6411890 DOI: 10.1038/s41598-019-40128-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/08/2019] [Indexed: 11/17/2022] Open
Abstract
The brain’s extracellular matrix (ECM) is a macromolecular network composed of glycosaminoglycans, proteoglycans, glycoproteins, and fibrous proteins. In vitro studies often use purified ECM proteins for cell culture coatings, however these may not represent the molecular complexity and heterogeneity of the brain’s ECM. To address this, we compared neural network activity (over 30 days in vitro) from primary neurons co-cultured with glia grown on ECM coatings from decellularized brain tissue (bECM) or MaxGel, a non-tissue-specific ECM. Cells were grown on a multi-electrode array (MEA) to enable noninvasive long-term interrogation of neuronal networks. In general, the presence of ECM accelerated the formation of networks without affecting the inherent network properties. However, specific features of network activity were dependent on the type of ECM: bECM enhanced network activity over a greater region of the MEA whereas MaxGel increased network burst rate associated with robust synaptophysin expression. These differences in network activity were not attributable to cellular composition, glial proliferation, or astrocyte phenotypes, which remained constant across experimental conditions. Collectively, the addition of ECM to neuronal cultures represents a reliable method to accelerate the development of mature neuronal networks, providing a means to enhance throughput for routine evaluation of neurotoxins and novel therapeutics.
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Affiliation(s)
- Doris Lam
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Heather A Enright
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Jose Cadena
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Sandra K G Peters
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Ana Paula Sales
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Joanne J Osburn
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - David A Soscia
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Kristen S Kulp
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Elizabeth K Wheeler
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Nicholas O Fischer
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA.
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George DS, Anderson WA, Sommerhage F, Willenberg AR, Hines RB, Bosak AJ, Willenberg BJ, Lambert S. Bundling of axons through a capillary alginate gel enhances the detection of axonal action potentials using microelectrode arrays. J Tissue Eng Regen Med 2019; 13:385-395. [PMID: 30636354 DOI: 10.1002/term.2793] [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: 06/14/2018] [Revised: 10/25/2018] [Accepted: 12/17/2018] [Indexed: 11/09/2022]
Abstract
Microelectrode arrays (MEAs) have become important tools in high throughput assessment of neuronal activity. However, geometric and electrical constraints largely limit their ability to detect action potentials to the neuronal soma. Enhancing the resolution of these systems to detect axonal action potentials has proved both challenging and complex. In this study, we have bundled sensory axons from dorsal root ganglia through a capillary alginate gel (Capgel™) interfaced with an MEA and observed an enhanced ability to detect spontaneous axonal activity compared with two-dimensional cultures. Moreover, this arrangement facilitated the long-term monitoring of spontaneous activity from the same bundle of axons at a single electrode. Finally, using waveform analysis for cultures treated with the nociceptor agonist capsaicin, we were able to dissect action potentials from multiple axons on an individual electrode, suggesting that this model can reproduce the functional complexity associated with sensory fascicles in vivo. This novel three-dimensional functional model of the peripheral nerve can be used to study the functional complexities of peripheral neuropathies and nerve regeneration as well as being utilized in the development of novel therapeutics.
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Affiliation(s)
- Dale S George
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Wesley A Anderson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Frank Sommerhage
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | - Alicia R Willenberg
- Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Robert B Hines
- Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Alexander J Bosak
- Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Bradley J Willenberg
- Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, FL, USA.,Saisijin Biotech LLC, St. Cloud, FL, USA
| | - Stephen Lambert
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, FL, USA
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Abstract
The firing rate of neuronal spiking in vitro and in vivo significantly varies over extended timescales, characterized by long-memory processes and complex statistics, and appears in spontaneous as well as evoked activity upon repeated stimulus presentation. These variations in response features and their statistics, in face of repeated instances of a given physical input, are ubiquitous in all levels of brain-behavior organization. They are expressed in single neuron and network response variability but even appear in variations of subjective percepts or psychophysical choices and have been described as stemming from history-dependent, stochastic, or rate-determined processes.But what are the sources underlying these temporally rich variations in firing rate? Are they determined by interactions of the nervous system as a whole, or do isolated, single neurons or neuronal networks already express these fluctuations independent of higher levels? These questions motivated the application of a method that allows for controlled and specific long-term activation of a single neuron or neuronal network, isolated from higher levels of cortical organization.This chapter highlights the research done in cultured cortical networks to study (1) the inherent non-stationarity of neuronal network activity, (2) single neuron response fluctuations and underlying processes, and (3) the interface layer between network and single cell, the non-stationary efficacy of the ensemble of synapses impinging onto the observed neuron.
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Closed-Loop Systems and In Vitro Neuronal Cultures: Overview and Applications. ADVANCES IN NEUROBIOLOGY 2019; 22:351-387. [DOI: 10.1007/978-3-030-11135-9_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Abstract
'Bursting', defined as periods of high-frequency firing of a neuron separated by periods of quiescence, has been observed in various neuronal systems, both in vitro and in vivo. It has been associated with a range of neuronal processes, including efficient information transfer and the formation of functional networks during development, and has been shown to be sensitive to genetic and pharmacological manipulations. Accurate detection of periods of bursting activity is thus an important aspect of characterising both spontaneous and evoked neuronal network activity. A wide variety of computational methods have been developed to detect periods of bursting in spike trains recorded from neuronal networks. In this chapter, we review several of the most popular and successful of these methods.
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Abstract
The brain is the most complex organ of the body, and many pathological processes underlying various brain disorders are poorly understood. Limited accessibility hinders observation of such processes in the in vivo brain, and experimental freedom is often insufficient to enable informative manipulations. In vitro preparations (brain slices or cultures of dissociated neurons) offer much better accessibility and reduced complexity and have yielded valuable new insights into various brain disorders. Both types of preparations have their advantages and limitations with regard to lifespan, preservation of in vivo brain structure, composition of cell types, and the link to behavioral outcome is often unclear in in vitro models. While these limitations hamper general usage of in vitro preparations to study, e.g., brain development, in vitro preparations are very useful to study neuronal and synaptic functioning under pathologic conditions. This chapter addresses several brain disorders, focusing on neuronal and synaptic functioning, as well as network aspects. Recent progress in the fields of brain circulation disorders, excitability disorders, and memory disorders will be discussed, as well as limitations of current in vitro models.
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Lee JY, Stiber M, Si D. Machine Learning of Spatiotemporal Bursting Behavior in Developing Neural Networks. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:348-351. [PMID: 30440408 DOI: 10.1109/embc.2018.8512358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As with other modern sciences (and their computational counterparts), neuroscience experiments can now produce data that, in terms of both quantity and complexity, challenge our interpretative abilities. It is relatively common to be faced with datasets containing many millions of neural spikes collected from tens of thousands of neurons. Traditional data analysis methods can, in a relatively straightforward manner, identify large-scale features in such data (e.g., on the scale of entire networks). What these approaches often cannot do is to connect macroscopic activity to the relevant small-scale behaviors of individual cells, especially in the face of ongoing background activity that is not relevant. This communication presents an application of machine learning techniques to bridge the gap between microscopic and macroscopic behaviors and identify the small-scale activity that leads to large-scale behavior, reducing data complexity to a level that can be amenable to further analysis. A small number of spatiotemporal spikes (among many millions) were found to provide reliable information about if and where a burst will occur.
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Synchronous firing patterns of induced pluripotent stem cell-derived cortical neurons depend on the network structure consisting of excitatory and inhibitory neurons. Biochem Biophys Res Commun 2018; 501:152-157. [DOI: 10.1016/j.bbrc.2018.04.197] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 04/25/2018] [Indexed: 01/17/2023]
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Valente P, Romei A, Fadda M, Sterlini B, Lonardoni D, Forte N, Fruscione F, Castroflorio E, Michetti C, Giansante G, Valtorta F, Tsai JW, Zara F, Nieus T, Corradi A, Fassio A, Baldelli P, Benfenati F. Constitutive Inactivation of the PRRT2 Gene Alters Short-Term Synaptic Plasticity and Promotes Network Hyperexcitability in Hippocampal Neurons. Cereb Cortex 2018; 29:2010-2033. [DOI: 10.1093/cercor/bhy079] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 03/13/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
| | - Alessandra Romei
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Manuela Fadda
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
| | - Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Davide Lonardoni
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Via Morego 30, Genova, Italy
| | - Nicola Forte
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Floriana Fruscione
- Laboratory of Neurogenetics and Neuroscience, Department Head-Neck and Neuroscience, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, Genova, Italy
| | - Enrico Castroflorio
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Caterina Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Giorgia Giansante
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
| | - Flavia Valtorta
- San Raffaele Scientific Institute and Vita Salute University, Via Olgettina 58, Milano, Italy
| | - Jin-Wu Tsai
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience, Department Head-Neck and Neuroscience, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, Genova, Italy
| | - Thierry Nieus
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Via Morego 30, Genova, Italy
| | - Anna Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
| | - Fabio Benfenati
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, Genova, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova, Italy
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Hassink GC, Raiss CC, Segers-Nolten IMJ, van Wezel RJA, Subramaniam V, le Feber J, Claessens MMAE. Exogenous α-synuclein hinders synaptic communication in cultured cortical primary rat neurons. PLoS One 2018; 13:e0193763. [PMID: 29565978 PMCID: PMC5863964 DOI: 10.1371/journal.pone.0193763] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 02/17/2018] [Indexed: 12/25/2022] Open
Abstract
Amyloid aggregates of the protein α-synuclein (αS) called Lewy Bodies (LB) and Lewy Neurites (LN) are the pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. We have previously shown that high extracellular αS concentrations can be toxic to cells and that neurons take up αS. Here we aimed to get more insight into the toxicity mechanism associated with high extracellular αS concentrations (50-100 μM). High extracellular αS concentrations resulted in a reduction of the firing rate of the neuronal network by disrupting synaptic transmission, while the neuronal ability to fire action potentials was still intact. Furthermore, many cells developed αS deposits larger than 500 nm within five days, but otherwise appeared healthy. Synaptic dysfunction clearly occurred before the establishment of large intracellular deposits and neuronal death, suggesting that an excessive extracellular αS concentration caused synaptic failure and which later possibly contributed to neuronal death.
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Affiliation(s)
- G. C. Hassink
- Clinical Neurophysiology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
- Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
| | - C. C. Raiss
- Nanobiophysics Group, MESA+ Institute for Nanotechnology, University of Twente, Postbus, Enschede, the Netherlands
| | - I. M. J. Segers-Nolten
- Nanobiophysics Group, MESA+ Institute for Nanotechnology, University of Twente, Postbus, Enschede, the Netherlands
| | - R. J. A. van Wezel
- Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
- Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Postbus, The Netherlands
| | - V. Subramaniam
- Nanobiophysics Group, MESA+ Institute for Nanotechnology, University of Twente, Postbus, Enschede, the Netherlands
| | - J. le Feber
- Clinical Neurophysiology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
- Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
- * E-mail:
| | - M. M. A. E. Claessens
- Clinical Neurophysiology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Postbus, Enschede, the Netherlands
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44
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Olde Scheper TV, Meredith RM, Mansvelder HD, van Pelt J, van Ooyen A. Dynamic Hebbian Cross-Correlation Learning Resolves the Spike Timing Dependent Plasticity Conundrum. Front Comput Neurosci 2018; 11:119. [PMID: 29375358 PMCID: PMC5768644 DOI: 10.3389/fncom.2017.00119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 12/22/2017] [Indexed: 11/13/2022] Open
Abstract
Spike Timing-Dependent Plasticity has been found to assume many different forms. The classic STDP curve, with one potentiating and one depressing window, is only one of many possible curves that describe synaptic learning using the STDP mechanism. It has been shown experimentally that STDP curves may contain multiple LTP and LTD windows of variable width, and even inverted windows. The underlying STDP mechanism that is capable of producing such an extensive, and apparently incompatible, range of learning curves is still under investigation. In this paper, it is shown that STDP originates from a combination of two dynamic Hebbian cross-correlations of local activity at the synapse. The correlation of the presynaptic activity with the local postsynaptic activity is a robust and reliable indicator of the discrepancy between the presynaptic neuron and the postsynaptic neuron's activity. The second correlation is between the local postsynaptic activity with dendritic activity which is a good indicator of matching local synaptic and dendritic activity. We show that this simple time-independent learning rule can give rise to many forms of the STDP learning curve. The rule regulates synaptic strength without the need for spike matching or other supervisory learning mechanisms. Local differences in dendritic activity at the synapse greatly affect the cross-correlation difference which determines the relative contributions of different neural activity sources. Dendritic activity due to nearby synapses, action potentials, both forward and back-propagating, as well as inhibitory synapses will dynamically modify the local activity at the synapse, and the resulting STDP learning rule. The dynamic Hebbian learning rule ensures furthermore, that the resulting synaptic strength is dynamically stable, and that interactions between synapses do not result in local instabilities. The rule clearly demonstrates that synapses function as independent localized computational entities, each contributing to the global activity, not in a simply linear fashion, but in a manner that is appropriate to achieve local and global stability of the neuron and the entire dendritic structure.
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Affiliation(s)
- Tjeerd V Olde Scheper
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Department of Computing and Communication Technologies, Faculty of Technology, Design and Environment, Oxford Brookes University, Oxford, United Kingdom
| | - Rhiannon M Meredith
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Jaap van Pelt
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Arjen van Ooyen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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45
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Park J, Kim G, Jung SD. A 128-Channel FPGA-Based Real-Time Spike-Sorting Bidirectional Closed-Loop Neural Interface System. IEEE Trans Neural Syst Rehabil Eng 2017; 25:2227-2238. [DOI: 10.1109/tnsre.2017.2697415] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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Shultz AM, Lee S, Guaraldi M, Shea TB, Yanco HC. Robot-Embodied Neuronal Networks as an Interactive Model of Learning. Open Neurol J 2017; 11:39-47. [PMID: 29151990 PMCID: PMC5678239 DOI: 10.2174/1874205x01711010039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/19/2017] [Accepted: 08/03/2017] [Indexed: 11/23/2022] Open
Abstract
Background and Objective: The reductionist approach of neuronal cell culture has been useful for analyses of synaptic signaling. Murine cortical neurons in culture spontaneously form an ex vivo network capable of transmitting complex signals, and have been useful for analyses of several fundamental aspects of neuronal development hitherto difficult to clarify in situ. However, these networks lack the ability to receive and respond to sensory input from the environment as do neurons in vivo. Establishment of these networks in culture chambers containing multi-electrode arrays allows recording of synaptic activity as well as stimulation. Method: This article describes the embodiment of ex vivo neuronal networks neurons in a closed-loop cybernetic system, consisting of digitized video signals as sensory input and a robot arm as motor output. Results: In this system, the neuronal network essentially functions as a simple central nervous system. This embodied network displays the ability to track a target in a naturalistic environment. These findings underscore that ex vivo neuronal networks can respond to sensory input and direct motor output. Conclusion: These analyses may contribute to optimization of neuronal-computer interfaces for perceptive and locomotive prosthetic applications. Ex vivo networks display critical alterations in signal patterns following treatment with subcytotoxic concentrations of amyloid-beta. Future studies including comparison of tracking accuracy of embodied networks prepared from mice harboring key mutations with those from normal mice, accompanied with exposure to Abeta and/or other neurotoxins, may provide a useful model system for monitoring subtle impairment of neuronal function as well as normal and abnormal development.
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Affiliation(s)
| | - Sangmook Lee
- Laboratory for Neuroscience, Department of Biological Sciences University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Mary Guaraldi
- Laboratory for Neuroscience, Department of Biological Sciences University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Thomas B Shea
- Laboratory for Neuroscience, Department of Biological Sciences University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Holly C Yanco
- Robotics Laboratory, Department of Computer Science, USA
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47
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Huang YT, Chang YL, Chen CC, Lai PY, Chan CK. Positive feedback and synchronized bursts in neuronal cultures. PLoS One 2017; 12:e0187276. [PMID: 29091966 PMCID: PMC5665536 DOI: 10.1371/journal.pone.0187276] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 10/17/2017] [Indexed: 01/05/2023] Open
Abstract
Synchronized bursts (SBs) with complex structures are common in neuronal cultures. Although the phenomenon of SBs has been discovered for a long time, its origin is still unclear. Here, we investigate the properties of these SBs in cultures grown on a multi-electrode array. We find that structures of these SBs are related to the different developmental stages of the cultures and these structures can be modified by changing the magnesium concentration in the culture medium; indicating that synaptic mechanism is involved in the generation of SBs. A model based on short term synaptic plasticity (STSP), recurrent connections and astrocytic recycling of neurotransmitters has been developed successfully to understand the observed structures of SBs in experiments. A phase diagram obtained from this model shows that networks exhibiting SBs are in a complex oscillatory state due to large enough positive feedback provided by synaptic facilitation and recurrent connections. In this model, while STSP controls the fast oscillations (∼ 100 ms) within a SB, the astrocytic recycling determines the slow time scale (∼10 s) of inter-burst intervals. Our study suggests that glia-neuron interactions can be important in the understanding of the complex dynamics of neuronal networks.
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Affiliation(s)
- Yu-Ting Huang
- Dept. of Physics and Center for Complex Systems, National Central University, Chungli, Taiwan 320, ROC
- Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Yu-Lin Chang
- Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Chun-Chung Chen
- Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Pik-Yin Lai
- Dept. of Physics and Center for Complex Systems, National Central University, Chungli, Taiwan 320, ROC
- * E-mail: (PYL); (CKC)
| | - C. K. Chan
- Dept. of Physics and Center for Complex Systems, National Central University, Chungli, Taiwan 320, ROC
- Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
- * E-mail: (PYL); (CKC)
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Kireev D, Seyock S, Lewen J, Maybeck V, Wolfrum B, Offenhäusser A. Graphene Multielectrode Arrays as a Versatile Tool for Extracellular Measurements. Adv Healthc Mater 2017; 6. [PMID: 28371490 DOI: 10.1002/adhm.201601433] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/05/2017] [Indexed: 11/12/2022]
Abstract
Graphene multielectrode arrays (GMEAs) presented in this work are used for cardio and neuronal extracellular recordings. The advantages of the graphene as a part of the multielectrode arrays are numerous: from a general flexibility and biocompatibility to the unique electronic properties of graphene. The devices used for extensive in vitro studies of a cardiac-like cell line and cortical neuronal networks show excellent ability to extracellularly detect action potentials with signal to noise ratios in the range of 45 ± 22 for HL-1 cells and 48 ± 26 for spontaneous bursting/spiking neuronal activity. Complex neuronal bursting activity patterns as well as a variety of characteristic shapes of HL-1 action potentials are recorded with the GMEAs. This paper illustrates that the potential applications of the GMEAs in biological and medical research are still numerous and diverse.
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Affiliation(s)
- Dmitry Kireev
- Institute of Bioelectronics (PGI‐8/ICS‐8)Forschungszentrum Jülich 52425 Jülich Germany
| | - Silke Seyock
- Institute of Bioelectronics (PGI‐8/ICS‐8)Forschungszentrum Jülich 52425 Jülich Germany
| | - Johannes Lewen
- Institute of Bioelectronics (PGI‐8/ICS‐8)Forschungszentrum Jülich 52425 Jülich Germany
| | - Vanessa Maybeck
- Institute of Bioelectronics (PGI‐8/ICS‐8)Forschungszentrum Jülich 52425 Jülich Germany
| | - Bernhard Wolfrum
- NeuroelectronicsMunich Schnool of BioengineeringDepartment of Electrical and Computer EngineeringTechnical University of Munich (TUM) & BCCN Munich Boltzmannstr. 11 85748 Garching Germany
| | - Andreas Offenhäusser
- Institute of Bioelectronics (PGI‐8/ICS‐8)Forschungszentrum Jülich 52425 Jülich Germany
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49
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Välkki IA, Lenk K, Mikkonen JE, Kapucu FE, Hyttinen JAK. Network-Wide Adaptive Burst Detection Depicts Neuronal Activity with Improved Accuracy. Front Comput Neurosci 2017; 11:40. [PMID: 28620291 PMCID: PMC5450420 DOI: 10.3389/fncom.2017.00040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 05/08/2017] [Indexed: 11/17/2022] Open
Abstract
Neuronal networks are often characterized by their spiking and bursting statistics. Previously, we introduced an adaptive burst analysis method which enhances the analysis power for neuronal networks with highly varying firing dynamics. The adaptation is based on single channels analyzing each element of a network separately. Such kind of analysis was adequate for the assessment of local behavior, where the analysis focuses on the neuronal activity in the vicinity of a single electrode. However, the assessment of the whole network may be hampered, if parts of the network are analyzed using different rules. Here, we test how using multiple channels and measurement time points affect adaptive burst detection. The main emphasis is, if network-wide adaptive burst detection can provide new insights into the assessment of network activity. Therefore, we propose a modification to the previously introduced inter-spike interval (ISI) histogram based cumulative moving average (CMA) algorithm to analyze multiple spike trains simultaneously. The network size can be freely defined, e.g., to include all the electrodes in a microelectrode array (MEA) recording. Additionally, the method can be applied on a series of measurements on the same network to pool the data for statistical analysis. Firstly, we apply both the original CMA-algorithm and our proposed network-wide CMA-algorithm on artificial spike trains to investigate how the modification changes the burst detection. Thereafter, we use the algorithms on MEA data of spontaneously active chemically manipulated in vitro rat cortical networks. Moreover, we compare the synchrony of the detected bursts introducing a new burst synchrony measure. Finally, we demonstrate how the bursting statistics can be used to classify networks by applying k-means clustering to the bursting statistics. The results show that the proposed network wide adaptive burst detection provides a method to unify the burst definition in the whole network and thus improves the assessment and classification of the neuronal activity, e.g., the effects of different pharmaceuticals. The results indicate that the novel method is adaptive enough to be usable on networks with different dynamics, and it is especially feasible when comparing the behavior of differently spiking networks, for example in developing networks.
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Affiliation(s)
- Inkeri A Välkki
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of TechnologyTampere, Finland
| | - Kerstin Lenk
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of TechnologyTampere, Finland
| | - Jarno E Mikkonen
- Department of Computer Science and Information Systems, University of JyväskyläJyväskylä, Finland
| | - Fikret E Kapucu
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of TechnologyTampere, Finland.,Pervasive Computing, Faculty of Computing and Electrical Engineering, Tampere University of TechnologyTampere, Finland
| | - Jari A K Hyttinen
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of TechnologyTampere, Finland
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50
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Mesoscale Architecture Shapes Initiation and Richness of Spontaneous Network Activity. J Neurosci 2017; 37:3972-3987. [PMID: 28292833 DOI: 10.1523/jneurosci.2552-16.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 02/06/2017] [Accepted: 02/11/2017] [Indexed: 11/21/2022] Open
Abstract
Spontaneous activity in the absence of external input, including propagating waves of activity, is a robust feature of neuronal networks in vivo and in vitro The neurophysiological and anatomical requirements for initiation and persistence of such activity, however, are poorly understood, as is their role in the function of neuronal networks. Computational network studies indicate that clustered connectivity may foster the generation, maintenance, and richness of spontaneous activity. Since this mesoscale architecture cannot be systematically modified in intact tissue, testing these predictions is impracticable in vivo Here, we investigate how the mesoscale structure shapes spontaneous activity in generic networks of rat cortical neurons in vitro In these networks, neurons spontaneously arrange into local clusters with high neurite density and form fasciculating long-range axons. We modified this structure by modulation of protein kinase C, an enzyme regulating neurite growth and cell migration. Inhibition of protein kinase C reduced neuronal aggregation and fasciculation of axons, i.e., promoted uniform architecture. Conversely, activation of protein kinase C promoted aggregation of neurons into clusters, local connectivity, and bundling of long-range axons. Supporting predictions from theory, clustered networks were more spontaneously active and generated diverse activity patterns. Neurons within clusters received stronger synaptic inputs and displayed increased membrane potential fluctuations. Intensified clustering promoted the initiation of synchronous bursting events but entailed incomplete network recruitment. Moderately clustered networks appear optimal for initiation and propagation of diverse patterns of activity. Our findings support a crucial role of the mesoscale architectures in the regulation of spontaneous activity dynamics.SIGNIFICANCE STATEMENT Computational studies predict richer and persisting spatiotemporal patterns of spontaneous activity in neuronal networks with neuron clustering. To test this, we created networks of varying architecture in vitro Supporting these predictions, the generation and spatiotemporal patterns of propagation were most variable in networks with intermediate clustering and lowest in uniform networks. Grid-like clustering, on the other hand, facilitated spontaneous activity but led to degenerating patterns of propagation. Neurons outside clusters had weaker synaptic input than neurons within clusters, in which increased membrane potential fluctuations facilitated the initiation of synchronized spike activity. Our results thus show that the intermediate level organization of neuronal networks strongly influences the dynamics of their activity.
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