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Meng J, Ahamed T, Yu B, Hung W, EI Mouridi S, Wang Z, Zhang Y, Wen Q, Boulin T, Gao S, Zhen M. A tonically active master neuron modulates mutually exclusive motor states at two timescales. SCIENCE ADVANCES 2024; 10:eadk0002. [PMID: 38598630 PMCID: PMC11006214 DOI: 10.1126/sciadv.adk0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 03/07/2024] [Indexed: 04/12/2024]
Abstract
Continuity of behaviors requires animals to make smooth transitions between mutually exclusive behavioral states. Neural principles that govern these transitions are not well understood. Caenorhabditis elegans spontaneously switch between two opposite motor states, forward and backward movement, a phenomenon thought to reflect the reciprocal inhibition between interneurons AVB and AVA. Here, we report that spontaneous locomotion and their corresponding motor circuits are not separately controlled. AVA and AVB are neither functionally equivalent nor strictly reciprocally inhibitory. AVA, but not AVB, maintains a depolarized membrane potential. While AVA phasically inhibits the forward promoting interneuron AVB at a fast timescale, it maintains a tonic, extrasynaptic excitation on AVB over the longer timescale. We propose that AVA, with tonic and phasic activity of opposite polarities on different timescales, acts as a master neuron to break the symmetry between the underlying forward and backward motor circuits. This master neuron model offers a parsimonious solution for sustained locomotion consisted of mutually exclusive motor states.
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Affiliation(s)
- Jun Meng
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Tosif Ahamed
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Bin Yu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Sonia EI Mouridi
- University Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, 69008 Lyon, France
| | - Zezhen Wang
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Yongning Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Quan Wen
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Thomas Boulin
- University Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, 69008 Lyon, France
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mei Zhen
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
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2
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Nicoletti M, Chiodo L, Loppini A, Liu Q, Folli V, Ruocco G, Filippi S. Biophysical modeling of the whole-cell dynamics of C. elegans motor and interneurons families. PLoS One 2024; 19:e0298105. [PMID: 38551921 PMCID: PMC10980225 DOI: 10.1371/journal.pone.0298105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/13/2024] [Indexed: 04/01/2024] Open
Abstract
The nematode Caenorhabditis elegans is a widely used model organism for neuroscience. Although its nervous system has been fully reconstructed, the physiological bases of single-neuron functioning are still poorly explored. Recently, many efforts have been dedicated to measuring signals from C. elegans neurons, revealing a rich repertoire of dynamics, including bistable responses, graded responses, and action potentials. Still, biophysical models able to reproduce such a broad range of electrical responses lack. Realistic electrophysiological descriptions started to be developed only recently, merging gene expression data with electrophysiological recordings, but with a large variety of cells yet to be modeled. In this work, we contribute to filling this gap by providing biophysically accurate models of six classes of C. elegans neurons, the AIY, RIM, and AVA interneurons, and the VA, VB, and VD motor neurons. We test our models by comparing computational and experimental time series and simulate knockout neurons, to identify the biophysical mechanisms at the basis of inter and motor neuron functioning. Our models represent a step forward toward the modeling of C. elegans neuronal networks and virtual experiments on the nematode nervous system.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
| | - Letizia Chiodo
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Alessandro Loppini
- Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Qiang Liu
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Viola Folli
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
- D-tails s.r.l., Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), Florence, Italy
- ICRANet—International Center for Relativistic Astrophysics Network, Pescara, Italy
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3
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Becerra D, Calixto A, Orio P. The Conscious Nematode: Exploring Hallmarks of Minimal Phenomenal Consciousness in Caenorhabditis Elegans. Int J Psychol Res (Medellin) 2023; 16:87-104. [PMID: 38106963 PMCID: PMC10723751 DOI: 10.21500/20112084.6487] [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: 06/16/2022] [Revised: 10/21/2022] [Accepted: 03/13/2023] [Indexed: 12/19/2023] Open
Abstract
While subcellular components of cognition and affectivity that involve the interaction between experience, environment, and physiology -such as learning, trauma, or emotion- are being identified, the physical mechanisms of phenomenal consciousness remain more elusive. We are interested in exploring whether ancient, simpler organisms such as nematodes have minimal consciousness. Is there something that feels like to be a worm? Or are worms blind machines? 'Simpler' models allow us to simultaneously extract data from multiple levels such as slow and fast neural dynamics, structural connectivity, molecular dynamics, behavior, decision making, etc., and thus, to test predictions of the current frameworks in dispute. In the present critical review, we summarize the current models of consciousness in order to reassess in light of the new evidence whether Caenorhabditis elegans, a nematode with a nervous system composed of 302 neurons, has minimal consciousness. We also suggest empirical paths to further advance consciousness research using C. elegans.
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Affiliation(s)
- Diego Becerra
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
- Doctorado en Ciencias, mención Biofísica y Biología Computacional, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
| | - Andrea Calixto
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
| | - Patricio Orio
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.Universidad de ValparaísoUniversidad de ValparaísoValparaísoChile
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4
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Doser R, Knight KM, Deihl E, Hoerndli F. Subcellular Imaging of Neuronal Calcium Handling In Vivo. J Vis Exp 2023:10.3791/64928. [PMID: 37010315 PMCID: PMC10937071 DOI: 10.3791/64928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
Abstract
Calcium (Ca2+) imaging has been largely used to examine neuronal activity, but it is becoming increasingly clear that subcellular Ca2+ handling is a crucial component of intracellular signaling. The visualization of subcellular Ca2+ dynamics in vivo, where neurons can be studied in their native, intact circuitry, has proven technically challenging in complex nervous systems. The transparency and relatively simple nervous system of the nematode Caenorhabditis elegans enable the cell-specific expression and in vivo visualization of fluorescent tags and indicators. Among these are fluorescent indicators that have been modified for use in the cytoplasm as well as various subcellular compartments, such as the mitochondria. This protocol enables non-ratiometric Ca2+ imaging in vivo with a subcellular resolution that permits the analysis of Ca2+ dynamics down to the level of individual dendritic spines and mitochondria. Here, two available genetically encoded indicators with different Ca2+ affinities are used to demonstrate the use of this protocol for measuring relative Ca2+ levels within the cytoplasm or mitochondrial matrix in a single pair of excitatory interneurons (AVA). Together with the genetic manipulations and longitudinal observations possible in C. elegans, this imaging protocol may be useful for answering questions regarding how Ca2+ handling regulates neuronal function and plasticity.
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Affiliation(s)
- Rachel Doser
- Department of Biomedical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences
| | - Kaz M Knight
- Department of Biomedical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences; Cellular and Molecular Biology Graduate Program, Colorado State University College of Veterinary Medicine and Biomedical Sciences
| | - Ennis Deihl
- Department of Biomedical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences
| | - Frederic Hoerndli
- Department of Biomedical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences;
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Gandolfi D, Mapelli J, Solinas SMG, Triebkorn P, D'Angelo E, Jirsa V, Migliore M. Full-scale scaffold model of the human hippocampus CA1 area. NATURE COMPUTATIONAL SCIENCE 2023; 3:264-276. [PMID: 38177882 PMCID: PMC10766517 DOI: 10.1038/s43588-023-00417-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 02/09/2023] [Indexed: 01/06/2024]
Abstract
The increasing availability of quantitative data on the human brain is opening new avenues to study neural function and dysfunction, thus bringing us closer and closer to the implementation of digital twin applications for personalized medicine. Here we provide a resource to the neuroscience community: a computational method to generate full-scale scaffold model of human brain regions starting from microscopy images. We have benchmarked the method to reconstruct the CA1 region of a right human hippocampus, which accounts for about half of the entire right hippocampal formation. Together with 3D soma positioning we provide a connectivity matrix generated using a morpho-anatomical connection strategy based on axonal and dendritic probability density functions accounting for morphological properties of hippocampal neurons. The data and algorithms are supplied in a ready-to-use format, suited to implement computational models at different scales and detail.
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Affiliation(s)
- Daniela Gandolfi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
| | - Jonathan Mapelli
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy.
| | - Sergio M G Solinas
- Department of Biomedical Science, University of Sassari, Sassari, Italy
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Paul Triebkorn
- Institut de Neurosciences des Systèmes, Aix-Marseille University, Marseille, France
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Pavia, Italy
| | - Viktor Jirsa
- Institut de Neurosciences des Systèmes, Aix-Marseille University, Marseille, France
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy.
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6
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Naudin L, Raison-Aubry L, Buhry L. A general pattern of non-spiking neuron dynamics under the effect of potassium and calcium channel modifications. J Comput Neurosci 2023; 51:173-186. [PMID: 36371576 DOI: 10.1007/s10827-022-00840-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 10/08/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
Abstract
Electrical activity of excitable cells results from ion exchanges through cell membranes, so that genetic or epigenetic changes in genes encoding ion channels are likely to affect neuronal electrical signaling throughout the brain. There is a large literature on the effect of variations in ion channels on the dynamics of spiking neurons that represent the main type of neurons found in the vertebrate nervous systems. Nevertheless, non-spiking neurons are also ubiquitous in many nervous tissues and play a critical role in the processing of some sensory systems. To our knowledge, however, how conductance variations affect the dynamics of non-spiking neurons has never been assessed. Based on experimental observations reported in the biological literature and on mathematical considerations, we first propose a phenotypic classification of non-spiking neurons. Then, we determine a general pattern of the phenotypic evolution of non-spiking neurons as a function of changes in calcium and potassium conductances. Furthermore, we study the homeostatic compensatory mechanisms of ion channels in a well-posed non-spiking retinal cone model. We show that there is a restricted range of ion conductance values for which the behavior and phenotype of the neuron are maintained. Finally, we discuss the implications of the phenotypic changes of individual cells at the level of neuronal network functioning of the C. elegans worm and the retina, which are two non-spiking nervous tissues composed of neurons with various phenotypes.
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Affiliation(s)
- Loïs Naudin
- Laboratoire Lorrain de Recherche en Informatique et ses Applications, CNRS, Université de Lorraine, Nancy, France.
| | - Laetitia Raison-Aubry
- Laboratoire Lorrain de Recherche en Informatique et ses Applications, CNRS, Université de Lorraine, Nancy, France
| | - Laure Buhry
- Laboratoire Lorrain de Recherche en Informatique et ses Applications, CNRS, Université de Lorraine, Nancy, France.
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7
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Nicoletti M, Luchetti N, Chiodo L, Loppini A, Folli V, Ruocco G, Filippi S. Modeling of olfactory transduction in AWC ON neuron via coupled electrical-calcium dynamics. Biomol Concepts 2023; 14:bmc-2022-0035. [PMID: 37574865 DOI: 10.1515/bmc-2022-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/28/2023] [Indexed: 08/15/2023] Open
Abstract
Amphid wing "C" (AWC) neurons are among the most important and studied neurons of the nematode Caenorhabditis elegans. In this work, we unify the existing electrical and intracellular calcium dynamics descriptions to obtain a biophysically accurate model of olfactory transduction in AWCON neurons. We study the membrane voltage and the intracellular calcium dynamics at different exposure times and odorant concentrations to grasp a complete picture of AWCON functioning. Moreover, we investigate the complex cascade of biochemical processes that allow AWC activation upon odor removal. We analyze the behavior of the different components of the models and, by suppressing them selectively, we extrapolate their contribution to the overall neuron response and study the resilience of the dynamical system. Our results are all in agreement with the available experimental data. Therefore, we provide an accurate mathematical and biophysical model for studying olfactory signal processing in C. elegans.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Nicole Luchetti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
| | | | - Viola Folli
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
- D-tails s.r.l., Via di Torre Rossa 66, 00165, Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), Florence, Italy
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8
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Naudin L, Jiménez Laredo JL, Liu Q, Corson N. Systematic generation of biophysically detailed models with generalization capability for non-spiking neurons. PLoS One 2022; 17:e0268380. [PMID: 35560186 PMCID: PMC9106219 DOI: 10.1371/journal.pone.0268380] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/28/2022] [Indexed: 11/18/2022] Open
Abstract
Unlike spiking neurons which compress continuous inputs into digital signals for transmitting information via action potentials, non-spiking neurons modulate analog signals through graded potential responses. Such neurons have been found in a large variety of nervous tissues in both vertebrate and invertebrate species, and have been proven to play a central role in neuronal information processing. If general and vast efforts have been made for many years to model spiking neurons using conductance-based models (CBMs), very few methods have been developed for non-spiking neurons. When a CBM is built to characterize the neuron behavior, it should be endowed with generalization capabilities (i.e. the ability to predict acceptable neuronal responses to different novel stimuli not used during the model’s building). Yet, since CBMs contain a large number of parameters, they may typically suffer from a lack of such a capability. In this paper, we propose a new systematic approach based on multi-objective optimization which builds general non-spiking models with generalization capabilities. The proposed approach only requires macroscopic experimental data from which all the model parameters are simultaneously determined without compromise. Such an approach is applied on three non-spiking neurons of the nematode Caenorhabditis elegans (C. elegans), a well-known model organism in neuroscience that predominantly transmits information through non-spiking signals. These three neurons, arbitrarily labeled by convention as RIM, AIY and AFD, represent, to date, the three possible forms of non-spiking neuronal responses of C. elegans.
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Affiliation(s)
- Loïs Naudin
- Department of Applied Mathematics, Normandie University, Le Havre, Normandie, France
- * E-mail:
| | | | - Qiang Liu
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong, SAR, China
| | - Nathalie Corson
- Department of Applied Mathematics, Normandie University, Le Havre, Normandie, France
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Xu H, Wang X, Zhang X, Cheng J, Zhang J, Chen M, Wu T. A Deep Learning Analysis Reveals Nitrogen-Doped Graphene Quantum Dots Damage Neurons of Nematode Caenorhabditis elegans. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:3314. [PMID: 34947663 PMCID: PMC8703693 DOI: 10.3390/nano11123314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/09/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022]
Abstract
Along with the rapidly increasing applications of nitrogen-doped graphene quantum dots (N-GQDs) in the field of biomedicine, the exposure of N-GQDs undoubtedly pose a risk to the health of human beings, especially in the nervous system. In view of the lack of data from in vivo studies, this study used the nematode Caenorhabditis elegans (C. elegans), which has become a valuable animal model in nanotoxicological studies due to its multiple advantages, to undertake a bio-safety assessment of N-GQDs in the nervous system with the assistance of a deep learning model. The findings suggested that accumulated N-GQDs in the nematodes' bodies damaged their normal behavior in a dose- and time-dependent manner, and the impairments of the nervous system were obviously severe when the exposure dosages were above 100 μg/mL. When assessing the morphological changes of neurons caused by N-GQDs, a quantitative image-based analysis based on a deep neural network algorithm (YOLACT) was used because traditional image-based analysis is labor-intensive and limited to qualitative evaluation. The quantitative results indicated that N-GQDs damaged dopaminergic and glutamatergic neurons, which are involved in the neurotoxic effects of N-GQDs in the nematode C. elegans. This study not only suggests a fast and economic C. elegans model to undertake the risk assessment of nanomaterials in the nervous system, but also provides a valuable deep learning approach to quantitatively track subtle morphological changes of neurons at an unbiased level in a nanotoxicological study using C. elegans.
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Affiliation(s)
- Hongsheng Xu
- College of Energy and Electrical Engineering, Hohai University, Nanjing 210098, China;
| | - Xinyu Wang
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
| | - Xiaomeng Zhang
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
| | - Jin Cheng
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
| | - Jixiang Zhang
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
| | - Min Chen
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
| | - Tianshu Wu
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China; (X.W.); (X.Z.); (J.C.); (J.Z.); (M.C.)
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10
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Ghirga S, Chiodo L, Marrocchio R, Orlandi JG, Loppini A. Inferring Excitatory and Inhibitory Connections in Neuronal Networks. ENTROPY 2021; 23:e23091185. [PMID: 34573810 PMCID: PMC8465838 DOI: 10.3390/e23091185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022]
Abstract
The comprehension of neuronal network functioning, from most basic mechanisms of signal transmission to complex patterns of memory and decision making, is at the basis of the modern research in experimental and computational neurophysiology. While mechanistic knowledge of neurons and synapses structure increased, the study of functional and effective networks is more complex, involving emergent phenomena, nonlinear responses, collective waves, correlation and causal interactions. Refined data analysis may help in inferring functional/effective interactions and connectivity from neuronal activity. The Transfer Entropy (TE) technique is, among other things, well suited to predict structural interactions between neurons, and to infer both effective and structural connectivity in small- and large-scale networks. To efficiently disentangle the excitatory and inhibitory neural activities, in the article we present a revised version of TE, split in two contributions and characterized by a suited delay time. The method is tested on in silico small neuronal networks, built to simulate the calcium activity as measured via calcium imaging in two-dimensional neuronal cultures. The inhibitory connections are well characterized, still preserving a high accuracy for excitatory connections prediction. The method could be applied to study effective and structural interactions in systems of excitable cells, both in physiological and in pathological conditions.
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Affiliation(s)
- Silvia Ghirga
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia (IIT), Viale Regina Elena 291, 00161 Roma, Italy;
| | - Letizia Chiodo
- Engineering Department, Campus Bio-Medico University of Rome, Via Álvaro del Portillo 21, 00154 Roma, Italy;
| | - Riccardo Marrocchio
- Institute of Sound and Vibration Research, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK;
| | | | - Alessandro Loppini
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia (IIT), Viale Regina Elena 291, 00161 Roma, Italy;
- Engineering Department, Campus Bio-Medico University of Rome, Via Álvaro del Portillo 21, 00154 Roma, Italy;
- Correspondence:
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11
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Correction: Biophysical modeling of C. elegans neurons: Single ion currents and whole-cell dynamics of AWCon and RMD. PLoS One 2021; 16:e0256930. [PMID: 34437650 PMCID: PMC8389473 DOI: 10.1371/journal.pone.0256930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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12
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Caprini D, Schwartz S, Lanza E, Milanetti E, Lucente V, Ferrarese G, Chiodo L, Nicoletti M, Folli V. A Shearless Microfluidic Device Detects a Role in Mechanosensitivity for AWC ON Neuron in Caenorhabditis elegans. Adv Biol (Weinh) 2021; 5:e2100927. [PMID: 34423577 DOI: 10.1002/adbi.202100927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/03/2021] [Indexed: 11/08/2022]
Abstract
AWC olfactory neurons are fundamental for chemotaxis toward volatile attractants in Caenorhabditis elegans. Here, it is shown that AWCON responds not only to chemicals but also to mechanical stimuli caused by fluid flow changes in a microfluidic device. The dynamics of calcium events are correlated with the stimulus amplitude. It is further shown that the mechanosensitivity of AWCON neurons has an intrinsic nature rather than a synaptic origin, and the calcium transient response is mediated by TAX-4 cGMP-gated cation channel, suggesting the involvement of one or more "odorant" receptors in AWCON mechano-transduction. In many cases, the responses show plateau properties resembling bistable calcium dynamics where neurons can switch from one stable state to the other. To investigate the unprecedentedly observed mechanosensitivity of AWCON neurons, a novel microfluidic device is designed to minimize the fluid shear flow in the arena hosting the nematodes. Animals in this device show reduced neuronal activation of AWCON neurons. The results observed indicate that the tangential component of the mechanical stress is the main contributor to the mechanosensitivity of AWCON . Furthermore, the microfluidic platform, integrating shearless perfusion and calcium imaging, provides a novel and more controlled solution for in vivo analysis both in micro-organisms and cultured cells.
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Affiliation(s)
- Davide Caprini
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Silvia Schwartz
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Enrico Lanza
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Edoardo Milanetti
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Valeria Lucente
- CREST OPTICS S.p.A., Via di Torre Rossa 66, Rome, 00165, Italy
| | - Giuseppe Ferrarese
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Martina Nicoletti
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Viola Folli
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
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13
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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14
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George VK, Puppo F, Silva GA. Computing Temporal Sequences Associated With Dynamic Patterns on the C. elegans Connectome. Front Syst Neurosci 2021; 15:564124. [PMID: 33767613 PMCID: PMC7985353 DOI: 10.3389/fnsys.2021.564124] [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: 05/20/2020] [Accepted: 02/04/2021] [Indexed: 12/03/2022] Open
Abstract
Understanding how the structural connectivity and spatial geometry of a network constrains the dynamics it is able to support is an active and open area of research. We simulated the plausible dynamics resulting from the known C. elegans connectome using a recent model and theoretical analysis that computes the dynamics of neurobiological networks by focusing on how local interactions among connected neurons give rise to the global dynamics in an emergent way. We studied the dynamics which resulted from stimulating a chemosensory neuron (ASEL) in a known feeding circuit, both in isolation and embedded in the full connectome. We show that contralateral motorneuron activations in ventral (VB) and dorsal (DB) classes of motorneurons emerged from the simulations, which are qualitatively similar to rhythmic motorneuron firing pattern associated with locomotion of the worm. One interpretation of these results is that there is an inherent—and we propose—purposeful structural wiring to the C. elegans connectome that has evolved to serve specific behavioral functions. To study network signaling pathways responsible for the dynamics we developed an analytic framework that constructs Temporal Sequences (TSeq), time-ordered walks of signals on graphs. We found that only 5% of TSeq are preserved between the isolated feeding network relative to its embedded counterpart. The remaining 95% of signaling pathways computed in the isolated network are not present in the embedded network. This suggests a cautionary note for computational studies of isolated neurobiological circuits and networks.
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Affiliation(s)
- Vivek Kurien George
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Center for Engineered Natural Intelligence, University of California, San Diego, San Diego, CA, United States
| | - Francesca Puppo
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Center for Engineered Natural Intelligence, University of California, San Diego, San Diego, CA, United States.,BioCircuits Institute, University of California, San Diego, San Diego, CA, United States
| | - Gabriel A Silva
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Center for Engineered Natural Intelligence, University of California, San Diego, San Diego, CA, United States.,BioCircuits Institute, University of California, San Diego, San Diego, CA, United States.,Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
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15
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16
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Abstract
Mechanosensing is a key feature through which organisms can receive inputs from the environment and convert them into specific functional and behavioral outputs. Mechanosensation occurs in many cells and tissues, regulating a plethora of molecular processes based on the distribution of forces and stresses both at the cell membrane and at the intracellular organelles levels, through complex interactions between cells’ microstructures, cytoskeleton, and extracellular matrix. Although several primary and secondary mechanisms have been shown to contribute to mechanosensation, a fundamental pathway in simple organisms and mammals involves the presence of specialized sensory neurons and the presence of different types of mechanosensitive ion channels on the neuronal cell membrane. In this contribution, we present a review of the main ion channels which have been proven to be significantly involved in mechanotransduction in neurons. Further, we discuss recent studies focused on the biological mechanisms and modeling of mechanosensitive ion channels’ gating, and on mechanotransduction modeling at different scales and levels of details.
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17
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Naudin L, Corson N, Aziz-Alaoui MA, Jiménez Laredo JL, Démare T. On the Modeling of the Three Types of Non-spiking Neurons of the Caenorhabditis elegans. Int J Neural Syst 2020; 31:2050063. [PMID: 33269660 DOI: 10.1142/s012906572050063x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The nematode Caenorhabditis elegans (C. elegans) is a well-known model organism in neuroscience. The relative simplicity of its nervous system, made up of few hundred neurons, shares some essential features with more sophisticated nervous systems, including the human one. If we are able to fully characterize the nervous system of this organism, we will be one step closer to understanding the mechanisms underlying the behavior of living things. Following a recently conducted electrophysiological survey on different C. elegans neurons, this paper aims at modeling the three non-spiking RIM, AIY and AFD neurons (arbitrarily named with three upper case letters by convention). To date, they represent the three possible forms of non-spiking neuronal responses of the C. elegans. To achieve this objective, we propose a conductance-based neuron model adapted to the electrophysiological features of each neuron. These features are based on current biological research and a series of in-silico experiments which use differential evolution to fit the model to experimental data. From the obtained results, we formulate a series of biological hypotheses regarding currents involved in the neuron dynamics. These models reproduce experimental data with a high degree of accuracy while being biologically consistent with state-of-the-art research.
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Affiliation(s)
- Loïs Naudin
- Normandie Univ, UNIHAVRE, LMAH, FR-CNRS-3335, ISCN, Le Havre 76600, France
| | - Nathalie Corson
- Normandie Univ, UNIHAVRE, LMAH, FR-CNRS-3335, ISCN, Le Havre 76600, France
| | - M A Aziz-Alaoui
- Normandie Univ, UNIHAVRE, LMAH, FR-CNRS-3335, ISCN, Le Havre 76600, France
| | | | - Thibaut Démare
- Normandie Univ, UNIHAVRE, LITIS, FR-CNRS-3638, ISCN, Le Havre 76600, France
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18
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Baggio G, Rutten V, Hennequin G, Zampieri S. Efficient communication over complex dynamical networks: The role of matrix non-normality. SCIENCE ADVANCES 2020; 6:eaba2282. [PMID: 32518824 PMCID: PMC7253166 DOI: 10.1126/sciadv.aba2282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
In both natural and engineered systems, communication often occurs dynamically over networks ranging from highly structured grids to largely disordered graphs. To use, or comprehend the use of, networks as efficient communication media requires understanding of how they propagate and transform information in the face of noise. Here, we develop a framework that enables us to examine how network structure, noise, and interference between consecutive packets jointly determine transmission performance in complex networks governed by linear dynamics. Mathematically, normal networks, which can be decomposed into separate low-dimensional information channels, suffer greatly from readout noise. Most details of their wiring have no impact on transmission quality. Non-normal networks, however, can largely cancel the effect of noise by transiently amplifying select input dimensions while ignoring others, resulting in higher net information throughput. Our theory could inform the design of new communication networks, as well as the optimal use of existing ones.
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Affiliation(s)
- Giacomo Baggio
- Department of Information Engineering, University of Padova, via Gradenigo, 6/B I-35131 Padova, Italy
| | - Virginia Rutten
- Gatsby Computational Neuroscience Unit, University College London, London W1T 4JG, UK
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Guillaume Hennequin
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Sandro Zampieri
- Department of Information Engineering, University of Padova, via Gradenigo, 6/B I-35131 Padova, Italy
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19
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Stringer RN, Jurkovicova-Tarabova B, Huang S, Haji-Ghassemi O, Idoux R, Liashenko A, Souza IA, Rzhepetskyy Y, Lacinova L, Van Petegem F, Zamponi GW, Pamphlett R, Weiss N. A rare CACNA1H variant associated with amyotrophic lateral sclerosis causes complete loss of Ca v3.2 T-type channel activity. Mol Brain 2020; 13:33. [PMID: 32143681 PMCID: PMC7060640 DOI: 10.1186/s13041-020-00577-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/02/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of cortical, brain stem and spinal motor neurons that leads to muscle weakness and death. A previous study implicated CACNA1H encoding for Cav3.2 calcium channels as a susceptibility gene in ALS. In the present study, two heterozygous CACNA1H variants were identified by whole genome sequencing in a small cohort of ALS patients. These variants were functionally characterized using patch clamp electrophysiology, biochemistry assays, and molecular modeling. A previously unreported c.454GTAC > G variant produced an inframe deletion of a highly conserved isoleucine residue in Cav3.2 (p.ΔI153) and caused a complete loss-of-function of the channel, with an additional dominant-negative effect on the wild-type channel when expressed in trans. In contrast, the c.3629C > T variant caused a missense substitution of a proline with a leucine (p.P1210L) and produced a comparatively mild alteration of Cav3.2 channel activity. The newly identified ΔI153 variant is the first to be reported to cause a complete loss of Cav3.2 channel function. These findings add to the notion that loss-of-function of Cav3.2 channels associated with rare CACNA1H variants may be risk factors in the complex etiology of ALS.
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Affiliation(s)
- Robin N. Stringer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Sun Huang
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Romane Idoux
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Anna Liashenko
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Ivana A. Souza
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Yuriy Rzhepetskyy
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Lubica Lacinova
- Center of Biosciences, Institute of Molecular Physiology and Genetics, Academy of Sciences, Bratislava, Slovakia
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Roger Pamphlett
- Discipline of Pathology, Brain and Mind Centre, The University of Sydney, Sydney, NSW Australia
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
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Milanetti E, Gosti G, De Flaviis L, Olimpieri PP, Schwartz S, Caprini D, Ruocco G, Folli V. Investigation of the binding between olfactory receptors and odorant molecules in C. elegans organism. Biophys Chem 2019; 255:106264. [DOI: 10.1016/j.bpc.2019.106264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 01/27/2023]
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