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Ji H, Chen D, Fang-Yen C. Segmentation-free measurement of locomotor frequency in Caenorhabditis elegans using image invariants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575892. [PMID: 38293059 PMCID: PMC10827210 DOI: 10.1101/2024.01.16.575892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
An animal's locomotor rate is an important indicator of its motility. In studies of the nematode C. elegans, assays of the frequency of body bending waves have often been used to discern the effects of mutations, drugs, or aging. Traditional manual methods for measuring locomotor frequency are low in throughput and subject to human error. Most current automated methods depend on image segmentation, which requires high image quality and is prone to errors. Here, we describe an algorithm for automated estimation of C. elegans locomotor frequency using image invariants, i.e., shape-based parameters that are independent of object translation, rotation, and scaling. For each video frame, the method calculates a combination of 8 Hu's moment invariants and a set of Maximally Stable Extremal Regions (MSER) invariants. The algorithm then calculates the locomotor frequency by computing the autocorrelation of the time sequence of the invariant ensemble. Results of our method show excellent agreement with manual or segmentation-based results over a wide range of frequencies. We show that compared to a segmentation-based method that analyzes a worm's shape and a method based on video covariance, our technique is more robust to low image quality and background noise. We demonstrate the system's capabilities by testing the effects of serotonin and serotonin pathway mutations on C. elegans locomotor frequency.
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2
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Li H, Li H, Zuo N, Lang D, Du W, Zhang P, Pan B. Can the concentration of environmentally persistent free radicals describe its toxicity to Caenorhabditis elegans? Evidence provided by neurotoxicity and oxidative stress. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133823. [PMID: 38442598 DOI: 10.1016/j.jhazmat.2024.133823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/04/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
Environmentally persistent free radicals (EPFRs) are emerging pollutants stabilized on or inside particles. Although the toxicity of EPFR-containing particles has been confirmed, the conclusions are always ambiguous because of the presence of various compositions. A clear dose-response relationship was always challenged by the fact that the concentrations of these coexisted components simultaneously changed with EPFR concentrations. Without these solid dose-response pieces of evidence, we could not confidently conclude the toxicity of EPFRs and the description of potential EPFR risks. In this study, we established a particle system with a fixed catechol concentration but different reaction times to obtain particles with different EPFR concentrations. Caenorhabditis elegans (C. elegans) in response to different EPFR concentrations was systematically investigated at multiple biological levels, including behavior observations and biochemical and transcriptome analyses. Our results showed that exposure to EPFRs disrupted the development and locomotion of C. elegans. EPFRs cause concentration-dependent neurotoxicity and oxidative damage to C. elegans, which could be attributed to reactive oxygen species (ROS) promoted by EPFRs. Furthermore, the expression of key genes related to neurons was downregulated, whereas antioxidative genes were upregulated. Overall, our results confirmed the toxicity from EPFRs and EPFR concentration as a rational parameter to describe the extent of toxicity.
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Affiliation(s)
- Huijie Li
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Hao Li
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
| | - Ning Zuo
- Yunnan Research Academy of Eco-environmental Science, Kunming 650034, China
| | - Di Lang
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Wei Du
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Peng Zhang
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Bo Pan
- Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
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Chen L, Su P, Wang Y, Liu Y, Chen LM, Gao S. CKR-1 orchestrates two motor states from a single motoneuron in C. elegans. iScience 2024; 27:109390. [PMID: 38510145 PMCID: PMC10952047 DOI: 10.1016/j.isci.2024.109390] [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: 09/27/2023] [Revised: 12/22/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Neuromodulation is pivotal in modifying neuronal properties and motor states. CKR-1, a homolog of the cholecystokinin receptor, modulates robust escape steering and undulation body bending in C. elegans. Nevertheless, the mechanisms through which CKR-1 governs these motor states remain elusive. We elucidate the head motoneuron SMD as the orchestrator of both motor states. This regulation involves two neuropeptides: NLP-12 from DVA enhances undulation body curvature, while NLP-18 from ASI amplifies Ω-turn head curvature. Moreover, synthetic NLP-12 and NLP-18 peptides elicit CKR-1-dependent currents in Xenopus oocytes and Ca2+ transients in SMD neurons. Notably, CKR-1 shows higher sensitivity to NLP-18 compared to NLP-12. In situ patch-clamp recordings reveal CKR-1, NLP-12, and NLP-18 are not essential for neurotransmission at C. elegans neuromuscular junction, suggesting that SMD independently regulates head and body bending. Our studies illustrate that a single motoneuron SMD utilizes a cholecystokinin receptor CKR-1 to integrate two motor states.
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Affiliation(s)
- Lili Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Pan Su
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ya Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuting Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Li-Ming Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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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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5
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Ji H, Chen D, Fang-Yen C. Automated multimodal imaging of Caenorhabditis elegans behavior in multi-well plates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579675. [PMID: 38405855 PMCID: PMC10888940 DOI: 10.1101/2024.02.09.579675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Large-scale assays of behavior in model organisms play an important role in genetic screens, drug testing, and the elucidation of gene-behavior relationships. We have developed an automated, high-throughput imaging and analysis method for assaying behaviors of the nematode C. elegans . We use high-resolution optical imaging to longitudinally record the behaviors of 96 animals at a time in multi-well plates, and computer vision software to quantify the animals' locomotor activity, behavioral states, and egg laying events. To demonstrate the capabilities of our system we used it to examine the role of serotonin in C. elegans behavior. We found that egg-laying events are preceded by a period of reduced locomotion, and that this decline in movement requires serotonin signaling. In addition, we identified novel roles of serotonin receptors SER-1 and SER-7 in regulating the effects of serotonin on egg laying across roaming, dwelling, and quiescent locomotor states. Our system will be useful for performing genetic or chemical screens for modulators of behavior.
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Piatkevich KD, Boyden ES. Optogenetic control of neural activity: The biophysics of microbial rhodopsins in neuroscience. Q Rev Biophys 2023; 57:e1. [PMID: 37831008 DOI: 10.1017/s0033583523000033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Optogenetics, the use of microbial rhodopsins to make the electrical activity of targeted neurons controllable by light, has swept through neuroscience, enabling thousands of scientists to study how specific neuron types contribute to behaviors and pathologies, and how they might serve as novel therapeutic targets. By activating a set of neurons, one can probe what functions they can initiate or sustain, and by silencing a set of neurons, one can probe the functions they are necessary for. We here review the biophysics of these molecules, asking why they became so useful in neuroscience for the study of brain circuitry. We review the history of the field, including early thinking, early experiments, applications of optogenetics, pre-optogenetics targeted neural control tools, and the history of discovering and characterizing microbial rhodopsins. We then review the biophysical attributes of rhodopsins that make them so useful to neuroscience - their classes and structure, their photocycles, their photocurrent magnitudes and kinetics, their action spectra, and their ion selectivity. Our hope is to convey to the reader how specific biophysical properties of these molecules made them especially useful to neuroscientists for a difficult problem - the control of high-speed electrical activity, with great precision and ease, in the brain.
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Affiliation(s)
- Kiryl D Piatkevich
- School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Edward S Boyden
- McGovern Institute and Koch Institute, Departments of Brain and Cognitive Sciences, Media Arts and Sciences, and Biological Engineering, K. Lisa Yang Center for Bionics and Center for Neurobiological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
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7
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Ijspeert AJ, Daley MA. Integration of feedforward and feedback control in the neuromechanics of vertebrate locomotion: a review of experimental, simulation and robotic studies. J Exp Biol 2023; 226:jeb245784. [PMID: 37565347 DOI: 10.1242/jeb.245784] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Animal locomotion is the result of complex and multi-layered interactions between the nervous system, the musculo-skeletal system and the environment. Decoding the underlying mechanisms requires an integrative approach. Comparative experimental biology has allowed researchers to study the underlying components and some of their interactions across diverse animals. These studies have shown that locomotor neural circuits are distributed in the spinal cord, the midbrain and higher brain regions in vertebrates. The spinal cord plays a key role in locomotor control because it contains central pattern generators (CPGs) - systems of coupled neuronal oscillators that provide coordinated rhythmic control of muscle activation that can be viewed as feedforward controllers - and multiple reflex loops that provide feedback mechanisms. These circuits are activated and modulated by descending pathways from the brain. The relative contributions of CPGs, feedback loops and descending modulation, and how these vary between species and locomotor conditions, remain poorly understood. Robots and neuromechanical simulations can complement experimental approaches by testing specific hypotheses and performing what-if scenarios. This Review will give an overview of key knowledge gained from comparative vertebrate experiments, and insights obtained from neuromechanical simulations and robotic approaches. We suggest that the roles of CPGs, feedback loops and descending modulation vary among animals depending on body size, intrinsic mechanical stability, time required to reach locomotor maturity and speed effects. We also hypothesize that distal joints rely more on feedback control compared with proximal joints. Finally, we highlight important opportunities to address fundamental biological questions through continued collaboration between experimentalists and engineers.
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Affiliation(s)
- Auke J Ijspeert
- BioRobotics Laboratory, EPFL - Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Monica A Daley
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, USA
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Ji H, Fouad AD, Li Z, Ruba A, Fang-Yen C. A proprioceptive feedback circuit drives Caenorhabditis elegans locomotor adaptation through dopamine signaling. Proc Natl Acad Sci U S A 2023; 120:e2219341120. [PMID: 37155851 PMCID: PMC10193984 DOI: 10.1073/pnas.2219341120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 04/14/2023] [Indexed: 05/10/2023] Open
Abstract
An animal adapts its motor behavior to navigate the external environment. This adaptation depends on proprioception, which provides feedback on an animal's body postures. How proprioception mechanisms interact with motor circuits and contribute to locomotor adaptation remains unclear. Here, we describe and characterize proprioception-mediated homeostatic control of undulatory movement in the roundworm Caenorhabditis elegans. We found that the worm responds to optogenetically or mechanically induced decreases in midbody bending amplitude by increasing its anterior amplitude. Conversely, it responds to increased midbody amplitude by decreasing the anterior amplitude. Using genetics, microfluidic and optogenetic perturbation response analyses, and optical neurophysiology, we elucidated the neural circuit underlying this compensatory postural response. The dopaminergic PDE neurons proprioceptively sense midbody bending and signal to AVK interneurons via the D2-like dopamine receptor DOP-3. The FMRFamide-like neuropeptide FLP-1, released by AVK, regulates SMB head motor neurons to modulate anterior bending. We propose that this homeostatic behavioral control optimizes locomotor efficiency. Our findings demonstrate a mechanism in which proprioception works with dopamine and neuropeptide signaling to mediate motor control, a motif that may be conserved in other animals.
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Affiliation(s)
- Hongfei Ji
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA19104
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH43210
| | - Anthony D. Fouad
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA19104
| | - Zihao Li
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA19104
| | - Andrew Ruba
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA19104
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA19104
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH43210
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
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Chen M, Feng D, Su H, Wang M, Su T. Neural Network-Based Autonomous Search Model with Undulatory Locomotion Inspired by Caenorhabditis Elegans. SENSORS (BASEL, SWITZERLAND) 2022; 22:8825. [PMID: 36433423 PMCID: PMC9692421 DOI: 10.3390/s22228825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 06/16/2023]
Abstract
Caenorhabditis elegans (C. elegans) exhibits sophisticated chemotaxis behavior with a unique locomotion pattern using a simple nervous system only and is, therefore, well suited to inspire simple, cost-effective robotic navigation schemes. Chemotaxis in C. elegans involves two complementary strategies: klinokinesis, which allows reorientation by sharp turns when moving away from targets; and klinotaxis, which gradually adjusts the direction of motion toward the preferred side throughout the movement. In this study, we developed an autonomous search model with undulatory locomotion that combines these two C. elegans chemotaxis strategies with its body undulatory locomotion. To search for peaks in environmental variables such as chemical concentrations and radiation in directions close to the steepest gradients, only one sensor is needed. To develop our model, we first evolved a central pattern generator and designed a minimal network unit with proprioceptive feedback to encode and propagate rhythmic signals; hence, we realized realistic undulatory locomotion. We then constructed adaptive sensory neuron models following real electrophysiological characteristics and incorporated a state-dependent gating mechanism, enabling the model to execute the two orientation strategies simultaneously according to information from a single sensor. Simulation results verified the effectiveness, superiority, and realness of the model. Our simply structured model exploits multiple biological mechanisms to search for the shortest-path concentration peak over a wide range of gradients and can serve as a theoretical prototype for worm-like navigation robots.
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Lu Y, Ahamed T, Mulcahy B, Meng J, Witvliet D, Guan SA, Holmyard D, Hung W, Wen Q, Chisholm AD, Samuel ADT, Zhen M. Extrasynaptic signaling enables an asymmetric juvenile motor circuit to produce symmetric undulation. Curr Biol 2022; 32:4631-4644.e5. [PMID: 36182701 PMCID: PMC9643663 DOI: 10.1016/j.cub.2022.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 06/17/2022] [Accepted: 09/01/2022] [Indexed: 01/28/2023]
Abstract
In many animals, there is a direct correspondence between the motor patterns that drive locomotion and the motor neuron innervation. For example, the adult C. elegans moves with symmetric and alternating dorsal-ventral bending waves arising from symmetric motor neuron input onto the dorsal and ventral muscles. In contrast to the adult, the C. elegans motor circuit at the juvenile larval stage has asymmetric wiring between motor neurons and muscles but still generates adult-like bending waves with dorsal-ventral symmetry. We show that in the juvenile circuit, wiring between excitatory and inhibitory motor neurons coordinates the contraction of dorsal muscles with relaxation of ventral muscles, producing dorsal bends. However, ventral bending is not driven by analogous wiring. Instead, ventral muscles are excited uniformly by premotor interneurons through extrasynaptic signaling. Ventral bends occur in anti-phasic entrainment to activity of the same motor neurons that drive dorsal bends. During maturation, the juvenile motor circuit is replaced by two motor subcircuits that separately drive dorsal and ventral bending. Modeling reveals that the juvenile's immature motor circuit is an adequate solution to generate adult-like dorsal-ventral bending before the animal matures. Developmental rewiring between functionally degenerate circuit solutions, which both generate symmetric bending patterns, minimizes behavioral disruption across maturation.
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Affiliation(s)
- Yangning Lu
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Tosif Ahamed
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Jun Meng
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Daniel Witvliet
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Sihui Asuka Guan
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Douglas Holmyard
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Quan Wen
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; School of Life Sciences, University of Science and Technology, Hefei, Anhui 230027, China
| | - Andrew D Chisholm
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Aravinthan D T Samuel
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Mei Zhen
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada.
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11
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Mechanosensitive body–brain interactions in Caenorhabditis elegans. Curr Opin Neurobiol 2022; 75:102574. [DOI: 10.1016/j.conb.2022.102574] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 03/30/2022] [Accepted: 05/06/2022] [Indexed: 12/13/2022]
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12
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Jonaitis J, MacLeod J, Pulver SR. Localization of muscarinic acetylcholine receptor-dependent rhythm-generating modules in the Drosophila larval locomotor network. J Neurophysiol 2022; 127:1098-1116. [PMID: 35294308 PMCID: PMC9018013 DOI: 10.1152/jn.00106.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/22/2022] Open
Abstract
Mechanisms of rhythm generation have been extensively studied in motor systems that control locomotion over terrain in limbed animals; however, much less is known about rhythm generation in soft-bodied terrestrial animals. Here we explored how muscarinic acetylcholine receptor (mAChR)-modulated rhythm-generating networks are distributed in the central nervous system (CNS) of soft-bodied Drosophila larvae. We measured fictive motor patterns in isolated CNS preparations, using a combination of Ca2+ imaging and electrophysiology while manipulating mAChR signaling pharmacologically. Bath application of the mAChR agonist oxotremorine potentiated bilaterally asymmetric activity in anterior thoracic regions and promoted bursting in posterior abdominal regions. Application of the mAChR antagonist scopolamine suppressed rhythm generation in these regions and blocked the effects of oxotremorine. Oxotremorine triggered fictive forward crawling in preparations without brain lobes. Oxotremorine also potentiated rhythmic activity in isolated posterior abdominal CNS segments as well as isolated anterior brain and thoracic regions, but it did not induce rhythmic activity in isolated anterior abdominal segments. Bath application of scopolamine to reduced preparations lowered baseline Ca2+ levels and abolished rhythmic activity. Overall, these results suggest that mAChR signaling plays a role in enabling rhythm generation at multiple sites in the larval CNS. This work furthers our understanding of motor control in soft-bodied locomotion and provides a foundation for study of rhythm-generating networks in an emerging genetically tractable locomotor system.NEW & NOTEWORTHY Using a combination of pharmacology, electrophysiology, and Ca2+ imaging, we find that signaling through mACh receptors plays a critical role in rhythmogenesis in different regions of the Drosophila larval CNS. mAChR-dependent rhythm generators reside in distal regions of the larval CNS and provide functional substrates for central pattern-generating networks (CPGs) underlying headsweep behavior and forward locomotion. This provides new insights into locomotor CPG operation in soft-bodied animals that navigate over terrain.
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Affiliation(s)
- Julius Jonaitis
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
| | - James MacLeod
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
| | - Stefan R Pulver
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
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13
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Yu B, Wang Y, Gao S. Motor Rhythm Dissection From the Backward Circuit in C. elegans. Front Mol Neurosci 2022; 15:845733. [PMID: 35370545 PMCID: PMC8966088 DOI: 10.3389/fnmol.2022.845733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/26/2022] [Indexed: 11/28/2022] Open
Abstract
Motor rhythm is initiated and sustained by oscillatory neuronal activity. We recently discovered that the A-class excitatory motor neurons (MNs) (A-MNs) function as intrinsic oscillators. They drive backward locomotion by generating rhythmic postsynaptic currents (rPSCs) in body wall muscles. Molecular underpinning of the rPSCs, however, is not fully elucidated. We report here that there are three types of the rPSC patterns, namely the phasic, tonic, and long-lasting, each with distinct kinetics and channel-dependence. The Na+ leak channel is required for all rPSC patterns. The tonic rPSCs exhibit strong dependence on the high-voltage-gated Ca2+ channels. Three K+ channels, the BK-type Ca2+-activated K+ channel, Na+-activated K+ channel, and voltage-gated K+ channel (Kv4), primarily inhibit tonic and long-lasting rPSCs with varying degrees and preferences. The elaborate regulation of rPSCs by different channels, through increasing or decreasing the rPSCs frequency and/or charge, correlates with the changes in the reversal velocity for respective channel mutants. The molecular dissection of different A-MNs-rPSC components therefore reveals different mechanisms for multiplex motor rhythm.
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Affiliation(s)
- Bin Yu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Ya Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Shangbang Gao,
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14
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Trojanowski NF, Fang-Yen C. Optogenetic Perturbation of Individual C. elegans Pharyngeal Neurons While Monitoring Feeding Behavior. Methods Mol Biol 2022; 2468:117-131. [PMID: 35320563 DOI: 10.1007/978-1-0716-2181-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Optogenetic approaches have proven to be powerful for examining the roles of specific neurons in generating behaviors, especially in systems where electrophysiological manipulation is not possible. Here we describe a method for optogenetically manipulating single pharyngeal neurons in intact C. elegans while monitoring pharyngeal behavior. This approach provides bidirectional and dynamic control of pharyngeal neural activity while quantitatively assessing behavior and has allowed us to test hypotheses about the roles of individual pharyngeal neurons in feeding behavior.
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Affiliation(s)
- Nicholas F Trojanowski
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Ji H, Fouad AD, Teng S, Liu A, Alvarez-Illera P, Yao B, Li Z, Fang-Yen C. Phase response analyses support a relaxation oscillator model of locomotor rhythm generation in Caenorhabditis elegans. eLife 2021; 10:e69905. [PMID: 34569934 PMCID: PMC8560089 DOI: 10.7554/elife.69905] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/24/2021] [Indexed: 01/25/2023] Open
Abstract
Neural circuits coordinate with muscles and sensory feedback to generate motor behaviors appropriate to an animal's environment. In C. elegans, the mechanisms by which the motor circuit generates undulations and modulates them based on the environment are largely unclear. We quantitatively analyzed C. elegans locomotion during free movement and during transient optogenetic muscle inhibition. Undulatory movements were highly asymmetrical with respect to the duration of bending and unbending during each cycle. Phase response curves induced by brief optogenetic inhibition of head muscles showed gradual increases and rapid decreases as a function of phase at which the perturbation was applied. A relaxation oscillator model based on proprioceptive thresholds that switch the active muscle moment was developed and is shown to quantitatively agree with data from free movement, phase responses, and previous results for gait adaptation to mechanical loadings. Our results suggest a neuromuscular mechanism underlying C. elegans motor pattern generation within a compact circuit.
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Affiliation(s)
- Hongfei Ji
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Anthony D Fouad
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Shelly Teng
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Alice Liu
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Pilar Alvarez-Illera
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Bowen Yao
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Zihao Li
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
- Department of Neuroscience, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
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16
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Godini R, Handley A, Pocock R. Transcription Factors That Control Behavior-Lessons From C. elegans. Front Neurosci 2021; 15:745376. [PMID: 34646119 PMCID: PMC8503520 DOI: 10.3389/fnins.2021.745376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/02/2021] [Indexed: 11/15/2022] Open
Abstract
Behavior encompasses the physical and chemical response to external and internal stimuli. Neurons, each with their own specific molecular identities, act in concert to perceive and relay these stimuli to drive behavior. Generating behavioral responses requires neurons that have the correct morphological, synaptic, and molecular identities. Transcription factors drive the specific gene expression patterns that define these identities, controlling almost every phenomenon in a cell from development to homeostasis. Therefore, transcription factors play an important role in generating and regulating behavior. Here, we describe the transcription factors, the pathways they regulate, and the neurons that drive chemosensation, mechanosensation, thermosensation, osmolarity sensing, complex, and sex-specific behaviors in the animal model Caenorhabditis elegans. We also discuss the current limitations in our knowledge, particularly our minimal understanding of how transcription factors contribute to the adaptive behavioral responses that are necessary for organismal survival.
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17
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Porto D, Matsunaga Y, Franke B, Williams RM, Qadota H, Mayans O, Benian GM, Lu H. Conformational changes in twitchin kinase in vivo revealed by FRET imaging of freely moving C. elegans. eLife 2021; 10:e66862. [PMID: 34569929 PMCID: PMC8523150 DOI: 10.7554/elife.66862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 09/24/2021] [Indexed: 02/07/2023] Open
Abstract
The force-induced unfolding and refolding of proteins is speculated to be a key mechanism in the sensing and transduction of mechanical signals in the living cell. Yet, little evidence has been gathered for its existence in vivo. Prominently, stretch-induced unfolding is postulated to be the activation mechanism of the twitchin/titin family of autoinhibited sarcomeric kinases linked to the mechanical stress response of muscle. To test the occurrence of mechanical kinase activation in living working muscle, we generated transgenic Caenorhabditis elegans expressing twitchin containing FRET moieties flanking the kinase domain and developed a quantitative technique for extracting FRET signals in freely moving C. elegans, using tracking and simultaneous imaging of animals in three channels (donor fluorescence, acceptor fluorescence, and transmitted light). Computer vision algorithms were used to extract fluorescence signals and muscle contraction states in each frame, in order to obtain fluorescence and body curvature measurements with spatial and temporal precision in vivo. The data revealed statistically significant periodic changes in FRET signals during muscle activity, consistent with a periodic change in the conformation of twitchin kinase. We conclude that stretch-unfolding of twitchin kinase occurs in the active muscle, whereby mechanical activity titrates the signaling pathway of this cytoskeletal kinase. We anticipate that the methods we have developed here could be applied to obtaining in vivo evidence for force-induced conformational changes or elastic behavior of other proteins not only in C. elegans but in other animals in which there is optical transparency (e.g., zebrafish).
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Affiliation(s)
- Daniel Porto
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
| | - Yohei Matsunaga
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Barbara Franke
- Department of Biology, University of KonstanzKonstanzGermany
| | - Rhys M Williams
- Department of Biology, University of KonstanzKonstanzGermany
| | - Hiroshi Qadota
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Olga Mayans
- Department of Biology, University of KonstanzKonstanzGermany
| | - Guy M Benian
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Hang Lu
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
- School of Chemical & Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
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18
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Abstract
In animals, proper locomotion is crucial to find mates and foods and avoid predators or dangers. Multiple sensory systems detect external and internal cues and integrate them to modulate motor outputs. Proprioception is the internal sense of body position, and proprioceptive control of locomotion is essential to generate and maintain precise patterns of movement or gaits. This proprioceptive feedback system is conserved in many animal species and is mediated by stretch-sensitive receptors called proprioceptors. Recent studies have identified multiple proprioceptive neurons and proprioceptors and their roles in the locomotion of various model organisms. In this review we describe molecular and neuronal mechanisms underlying proprioceptive feedback systems in C. elegans, Drosophila, and mice.
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Affiliation(s)
- Kyeong Min Moon
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - Jimin Kim
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - Yurim Seong
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - Byung-Chang Suh
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - KyeongJin Kang
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
- KBRI (Korea Brain Research Institute), Daegu 41068, Korea
| | - Han Kyoung Choe
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
- KBRI (Korea Brain Research Institute), Daegu 41068, Korea
| | - Kyuhyung Kim
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
- KBRI (Korea Brain Research Institute), Daegu 41068, Korea
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19
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Haspel G, Severi KE, Fauci LJ, Cohen N, Tytell ED, Morgan JR. Resilience of neural networks for locomotion. J Physiol 2021; 599:3825-3840. [PMID: 34187088 DOI: 10.1113/jp279214] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/22/2021] [Indexed: 01/15/2023] Open
Abstract
Locomotion is an essential behaviour for the survival of all animals. The neural circuitry underlying locomotion is therefore highly robust to a wide variety of perturbations, including injury and abrupt changes in the environment. In the short term, fault tolerance in neural networks allows locomotion to persist immediately after mild to moderate injury. In the longer term, in many invertebrates and vertebrates, neural reorganization including anatomical regeneration can restore locomotion after severe perturbations that initially caused paralysis. Despite decades of research, very little is known about the mechanisms underlying locomotor resilience at the level of the underlying neural circuits and coordination of central pattern generators (CPGs). Undulatory locomotion is an ideal behaviour for exploring principles of circuit organization, neural control and resilience of locomotion, offering a number of unique advantages including experimental accessibility and modelling tractability. In comparing three well-characterized undulatory swimmers, lampreys, larval zebrafish and Caenorhabditis elegans, we find similarities in the manifestation of locomotor resilience. To advance our understanding, we propose a comparative approach, integrating experimental and modelling studies, that will allow the field to begin identifying shared and distinct solutions for overcoming perturbations to persist in orchestrating this essential behaviour.
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Affiliation(s)
- Gal Haspel
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | - Kristen E Severi
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | - Lisa J Fauci
- Department of Mathematics, Tulane University, New Orleans, LA, 70118, USA
| | - Netta Cohen
- School of Computing, University of Leeds, Leeds, LS2 9JT, UK
| | - Eric D Tytell
- Department of Biology, Tufts University, Medford, MA, 02155, USA
| | - Jennifer R Morgan
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
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20
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Xu Y, Zhang L, Liu Y, Topalidou I, Hassinan C, Ailion M, Zhao Z, Wang T, Chen Z, Bai J. Dopamine receptor DOP-1 engages a sleep pathway to modulate swimming in C. elegans. iScience 2021; 24:102247. [PMID: 33796839 PMCID: PMC7995527 DOI: 10.1016/j.isci.2021.102247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/06/2021] [Accepted: 02/25/2021] [Indexed: 12/26/2022] Open
Abstract
Animals require robust yet flexible programs to support locomotion. Here we report a pathway that connects the D1-like dopamine receptor DOP-1 with a sleep mechanism to modulate swimming in C. elegans. We show that DOP-1 plays a negative role in sustaining swimming behavior. By contrast, a pathway through the D2-like dopamine receptor DOP-3 negatively regulates the initiation of swimming, but its impact fades quickly over a few minutes. We find that DOP-1 and the GPCR kinase (G-protein-coupled receptor kinase-2) function in the sleep interneuron RIS, where DOP-1 modulates the secretion of a sleep neuropeptide FLP-11. We further show that DOP-1 and FLP-11 act in the same pathway to modulate swimming. Together, these results delineate a functional connection between a dopamine receptor and a sleep program to regulate swimming in C. elegans. The temporal transition between DOP-3 and DOP-1 pathways highlights the dynamic nature of neuromodulation for rhythmic movements that persist over time.
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Affiliation(s)
- Ye Xu
- Department of Clinical Medicine, Nanjing Medical University, Nanjing 211166, P. R. China.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA.,Department of Neurology, First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Hainan 570102, P. R. China
| | - Lin Zhang
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA
| | - Yan Liu
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA
| | - Irini Topalidou
- Department of Biochemistry, University of Washington, WA 98195
| | - Cera Hassinan
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98019
| | - Michael Ailion
- Department of Biochemistry, University of Washington, WA 98195
| | - Zhenqiang Zhao
- Department of Neurology, First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Hainan 570102, P. R. China
| | - Tan Wang
- Department of Neurology, First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Hainan 570102, P. R. China
| | - Zhibin Chen
- Department of Clinical Medicine, Nanjing Medical University, Nanjing 211166, P. R. China.,Department of Neurology, First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Hainan 570102, P. R. China
| | - Jihong Bai
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98019.,Department of Biochemistry, University of Washington, WA 98195
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21
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Inhibition Underlies Fast Undulatory Locomotion in Caenorhabditis elegans. eNeuro 2021; 8:ENEURO.0241-20.2020. [PMID: 33361147 PMCID: PMC7986531 DOI: 10.1523/eneuro.0241-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/20/2020] [Accepted: 12/01/2020] [Indexed: 12/21/2022] Open
Abstract
Inhibition plays important roles in modulating the neural activities of sensory and motor systems at different levels from synapses to brain regions. To achieve coordinated movement, motor systems produce alternating contractions of antagonist muscles, whether along the body axis or within and among limbs, which often involves direct or indirect cross-inhibitory pathways. In the nematode Caenorhabditis elegans, a small network involving excitatory cholinergic and inhibitory GABAergic motoneurons generates the dorsoventral alternation of body-wall muscles that supports undulatory locomotion. Inhibition has been suggested to be necessary for backward undulation because mutants that are defective in GABA transmission exhibit a shrinking phenotype in response to a harsh touch to the head, whereas wild-type animals produce a backward escape response. Here, we demonstrate that the shrinking phenotype is exhibited by wild-type as well as mutant animals in response to harsh touch to the head or tail, but only GABA transmission mutants show slow locomotion after stimulation. Impairment of GABA transmission, either genetically or optogenetically, induces lower undulation frequency and lower translocation speed during crawling and swimming in both directions. The activity patterns of GABAergic motoneurons are different during low-frequency and high-frequency undulation. During low-frequency undulation, GABAergic VD and DD motoneurons show correlated activity patterns, while during high-frequency undulation, their activity alternates. The experimental results suggest at least three non-mutually exclusive roles for inhibition that could underlie fast undulatory locomotion in C. elegans, which we tested with computational models: cross-inhibition or disinhibition of body-wall muscles, or neuronal reset.
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22
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Fouad AD, Liu A, Du A, Bhirgoo PD, Fang-Yen C. Thermal laser ablation with tunable lesion size reveals multiple origins of seizure-like convulsions in Caenorhabditis elegans. Sci Rep 2021; 11:5084. [PMID: 33658607 PMCID: PMC7930185 DOI: 10.1038/s41598-021-84516-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/12/2021] [Indexed: 11/16/2022] Open
Abstract
Laser microsurgery has long been an important means of assessing the functions of specific cells and tissues. Most laser ablation systems use short, highly focused laser pulses to create plasma-mediated lesions with dimensions on the order of the wavelength of light. While the small size of the lesion enables ablation with high spatial resolution, it also makes it difficult to ablate larger structures. We developed an infrared laser ablation system capable of thermally lesioning tissues with spot sizes tunable by the duration and amplitude of laser pulses. We used our laser system in the roundworm C. elegans to kill single neurons and to sever the dorsal and ventral nerve cords, structures that are difficult to lesion using a plasma-based ablation system. We used these ablations to investigate the source of convulsions in a gain-of-function mutant for the acetylcholine receptor ACR-2. Severing the ventral nerve cord caused convulsions to occur independently anterior and posterior to the lesion, suggesting that convulsions can arise independently from distinct subsets of the motor circuit.
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Affiliation(s)
- Anthony D Fouad
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Alice Liu
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Angelica Du
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Priya D Bhirgoo
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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23
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Olivares E, Izquierdo EJ, Beer RD. A Neuromechanical Model of Multiple Network Rhythmic Pattern Generators for Forward Locomotion in C. elegans. Front Comput Neurosci 2021; 15:572339. [PMID: 33679357 PMCID: PMC7930337 DOI: 10.3389/fncom.2021.572339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 01/21/2021] [Indexed: 12/04/2022] Open
Abstract
Multiple mechanisms contribute to the generation, propagation, and coordination of the rhythmic patterns necessary for locomotion in Caenorhabditis elegans. Current experiments have focused on two possibilities: pacemaker neurons and stretch-receptor feedback. Here, we focus on whether it is possible that a chain of multiple network rhythmic pattern generators in the ventral nerve cord also contribute to locomotion. We use a simulation model to search for parameters of the anatomically constrained ventral nerve cord circuit that, when embodied and situated, can drive forward locomotion on agar, in the absence of pacemaker neurons or stretch-receptor feedback. Systematic exploration of the space of possible solutions reveals that there are multiple configurations that result in locomotion that is consistent with certain aspects of the kinematics of worm locomotion on agar. Analysis of the best solutions reveals that gap junctions between different classes of motorneurons in the ventral nerve cord can play key roles in coordinating the multiple rhythmic pattern generators.
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Affiliation(s)
- Erick Olivares
- Cognitive Science Program, Indiana University Bloomington, Bloomington, IN, United States
| | - Eduardo J. Izquierdo
- Cognitive Science Program, Indiana University Bloomington, Bloomington, IN, United States
- Luddy School of Informatics, Computing, and Engineering, Indiana University Bloomington, Bloomington, IN, United States
| | - Randall D. Beer
- Cognitive Science Program, Indiana University Bloomington, Bloomington, IN, United States
- Luddy School of Informatics, Computing, and Engineering, Indiana University Bloomington, Bloomington, IN, United States
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24
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Maertens T, Schöll E, Ruiz J, Hövel P. Multilayer network analysis of C. elegans: Looking into the locomotory circuitry. Neurocomputing 2021. [DOI: 10.1016/j.neucom.2020.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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25
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Yemini E, Lin A, Nejatbakhsh A, Varol E, Sun R, Mena GE, Samuel ADT, Paninski L, Venkatachalam V, Hobert O. NeuroPAL: A Multicolor Atlas for Whole-Brain Neuronal Identification in C. elegans. Cell 2021; 184:272-288.e11. [PMID: 33378642 PMCID: PMC10494711 DOI: 10.1016/j.cell.2020.12.012] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 06/30/2020] [Accepted: 12/08/2020] [Indexed: 12/31/2022]
Abstract
Comprehensively resolving neuronal identities in whole-brain images is a major challenge. We achieve this in C. elegans by engineering a multicolor transgene called NeuroPAL (a neuronal polychromatic atlas of landmarks). NeuroPAL worms share a stereotypical multicolor fluorescence map for the entire hermaphrodite nervous system that resolves all neuronal identities. Neurons labeled with NeuroPAL do not exhibit fluorescence in the green, cyan, or yellow emission channels, allowing the transgene to be used with numerous reporters of gene expression or neuronal dynamics. We showcase three applications that leverage NeuroPAL for nervous-system-wide neuronal identification. First, we determine the brainwide expression patterns of all metabotropic receptors for acetylcholine, GABA, and glutamate, completing a map of this communication network. Second, we uncover changes in cell fate caused by transcription factor mutations. Third, we record brainwide activity in response to attractive and repulsive chemosensory cues, characterizing multimodal coding for these stimuli.
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Affiliation(s)
- Eviatar Yemini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA.
| | - Albert Lin
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Amin Nejatbakhsh
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Erdem Varol
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Ruoxi Sun
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Gonzalo E Mena
- Department of Statistics and Data Science Initiative, Harvard University, Cambridge, MA 02138, USA
| | - Aravinthan D T Samuel
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Liam Paninski
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | | | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
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26
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Sana SS, Dogiparthi LK, Gangadhar L, Chakravorty A, Abhishek N. Effects of microplastics and nanoplastics on marine environment and human health. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44743-44756. [PMID: 32876819 DOI: 10.1007/s11356-020-10573-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 08/19/2020] [Indexed: 05/14/2023]
Abstract
Microplastics (MPs) with an average size of less than 5 mm, along with nanoplastics (NPs) of an average size of fewer than 0.1 μm are the result of huge plastic waste fragmentation or straight environmental emissions. Pollution from micro- and nanoplastics is a worldwide paradigm that raises environmental and human health concerns. They may also comprise very harmful chemicals that are implemented in plants and animals when MPs/NPs are used that may lead to higher accumulation of these compounds in food chains. In addition, higher surface area-to-volume ratio, characteristic of MPs/NPs can contribute to their potentially harmful impact as other pollutants, like continuous organic contaminants, can also be bio-accumulated and adsorbed. A complex issue correlated with MPs/NPs is their ability to absorb and interact with other common pollutants in the environment, such as metals, pharmaceuticals, and other contaminants. Thus, MPs/NPs can directly influence on destiny and toxicity of these substances to the environment and organisms. In this review, first, we introduce possible sources and formation, their destinies, and environmental impact of MPs/NPs and then explain feasible paths of all these particles entering the human body. Then, the review highlights the effect of MPs/NPs on human health. Finally, it provides a brief summary of the potential as well as the neurological toxicity of MPs/NPs.
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Affiliation(s)
- Siva Sankar Sana
- School of Chemical Engineering and Technology, North University of China, Taiyuan, 030051, China.
| | - Lakshman Kumar Dogiparthi
- Department of Pharmacognosy and Phytochemistry, Chebrolu Hanumaiah Institute of Pharmaceutical Sciences, Guntur-522019, Andhra Pradesh, India
| | - Lekshmi Gangadhar
- Department of Nanotechnology, Noorul Islam Center for Higher Education, Thuckalay, Nagarcoil, Tamilnadu, India
| | - Arghya Chakravorty
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Nalluri Abhishek
- Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
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27
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Targeted Central Nervous System Irradiation of Caenorhabditis elegans Induces a Limited Effect on Motility. BIOLOGY 2020; 9:biology9090289. [PMID: 32937967 PMCID: PMC7564402 DOI: 10.3390/biology9090289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/29/2022]
Abstract
To clarify the tissue responsible for a biological function, that function can be experimentally perturbed by an external stimulus, such as radiation. Radiation can be precisely and finely administered and any subsequent change in function examined. To investigate the involvement of the central nervous system (CNS) in Caenorhabditis elegans’ locomotion, we irradiated a limited 20-µm-diameter area of the CNS with a single dose and evaluated the resulting effects on motility. However, whether irradiated area (beam size)-dependent or dose-dependent effects on motility occur via targeted irradiation remain unknown. In the present study, we examined the irradiated area- and dose-dependent effects of CNS-targeted irradiation on the motility of C. elegans using a collimating microbeam system and confirmed the involvement of the CNS and body-wall muscle cells around the CNS in motility. After CNS-targeted microbeam irradiation, C. elegans’ motility was assayed. The results demonstrated a dose-dependent effect of CNS-targeted irradiation on motility reflecting direct effects on the irradiated CNS. In addition, when irradiated with 1000-Gy irradiation, irradiated area (beam size)-dependent effects were observed. This method has two technical advantages: Performing a series of on-chip imaging analyses before and after irradiation and targeted irradiation using a distinct ion-beam size.
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28
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Modzelewska K, Brown L, Culotti J, Moghal N. Sensory regulated Wnt production from neurons helps make organ development robust to environmental changes in C. elegans. Development 2020; 147:dev186080. [PMID: 32586974 DOI: 10.1242/dev.186080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 06/13/2020] [Indexed: 11/20/2022]
Abstract
Long-term survival of an animal species depends on development being robust to environmental variations and climate changes. We used C. elegans to study how mechanisms that sense environmental changes trigger adaptive responses that ensure animals develop properly. In water, the nervous system induces an adaptive response that reinforces vulval development through an unknown backup signal for vulval induction. This response involves the heterotrimeric G-protein EGL-30//Gαq acting in motor neurons. It also requires body-wall muscle, which is excited by EGL-30-stimulated synaptic transmission, suggesting a behavioral function of neurons induces backup signal production from muscle. We now report that increased acetylcholine during liquid growth activates an EGL-30-Rho pathway, distinct from the synaptic transmission pathway, that increases Wnt production from motor neurons. We also provide evidence that this neuronal Wnt contributes to EGL-30-stimulated vulval development, with muscle producing a parallel developmental signal. As diverse sensory modalities stimulate motor neurons via acetylcholine, this mechanism enables broad sensory perception to enhance Wnt-dependent development. Thus, sensory perception improves animal fitness by activating distinct neuronal functions that trigger adaptive changes in both behavior and developmental processes.
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Affiliation(s)
- Katarzyna Modzelewska
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Louise Brown
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Joseph Culotti
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Nadeem Moghal
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario, M5G 1L7, Canada
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Zhang Y, Zhang W, Zeng K, Ao Y, Wang M, Yu Z, Qi F, Yu W, Mao H, Tao L, Zhang C, Tan TTY, Yang X, Pu K, Gao S. Upconversion Nanoparticles-Based Multiplex Protein Activation to Neuron Ablation for Locomotion Regulation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1906797. [PMID: 32003923 DOI: 10.1002/smll.201906797] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/06/2020] [Indexed: 05/24/2023]
Abstract
The optogenetic neuron ablation approach enables noninvasive remote decoding of specific neuron function within a complex living organism in high spatiotemporal resolution. However, it suffers from shallow tissue penetration of visible light with low ablation efficiency. This study reports a upconversion nanoparticle (UCNP)-based multiplex proteins activation tool to ablate deep-tissue neurons for locomotion modulation. By optimizing the dopant contents and nanoarchitecure, over 300-fold enhancement of blue (450-470 nm) and red (590-610 nm) emissions from UCNPs is achieved upon 808 nm irradiation. Such emissions simultaneously activate mini singlet oxygen generator and Chrimson, leading to boosted near infrared (NIR) light-induced neuronal ablation efficiency due to the synergism between singlet oxygen generation and intracellular Ca2+ elevation. The loss of neurons severely inhibits reverse locomotion, revealing the instructive role of neurons in controlling motor activity. The deep penetrance NIR light makes the current system feasible for in vivo deep-tissue neuron elimination. The results not only provide a rapidly adoptable platform to efficient photoablate single- and multiple-cells, but also define the neural circuits underlying behavior, with potential for development of remote therapy in diseases.
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Affiliation(s)
- Yan Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- National Engineering Research Center for Nanomedicine, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Wanmei Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- National Engineering Research Center for Nanomedicine, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Kanghua Zeng
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yanxiao Ao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- National Engineering Research Center for Nanomedicine, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Mengdie Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, P. R. China
| | - Zhongzheng Yu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore, 637457, Singapore
| | - Fukang Qi
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Weiwei Yu
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P. R. China
| | - Heng Mao
- LMAM, School of Mathematical Sciences, Peking University, Beijing, 100871, P. R. China
| | - Louis Tao
- Center for Quantitative Biology, Peking University, Beijing, 100871, P. R. China
| | - Cuntai Zhang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P. R. China
| | - Timothy Thatt Yang Tan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore, 637457, Singapore
| | - Xiangliang Yang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- National Engineering Research Center for Nanomedicine, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Kanyi Pu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore, 637457, Singapore
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P. R. China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
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30
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Kaplan HS, Salazar Thula O, Khoss N, Zimmer M. Nested Neuronal Dynamics Orchestrate a Behavioral Hierarchy across Timescales. Neuron 2019; 105:562-576.e9. [PMID: 31786012 PMCID: PMC7014571 DOI: 10.1016/j.neuron.2019.10.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 09/19/2019] [Accepted: 10/28/2019] [Indexed: 01/01/2023]
Abstract
Classical and modern ethological studies suggest that animal behavior is organized hierarchically across timescales, such that longer-timescale behaviors are composed of specific shorter-timescale actions. Despite progress relating neuronal dynamics to single-timescale behavior, it remains unclear how different timescale dynamics interact to give rise to such higher-order behavioral organization. Here, we show, in the nematode Caenorhabditis elegans, that a behavioral hierarchy spanning three timescales is implemented by nested neuronal dynamics. At the uppermost hierarchical level, slow neuronal population dynamics spanning brain and motor periphery control two faster motor neuron oscillations, toggling them between different activity states and functional roles. At lower hierarchical levels, these faster oscillations are further nested in a manner that enables flexible behavioral control in an otherwise rigid hierarchical framework. Our findings establish nested neuronal activity patterns as a repeated dynamical motif of the C. elegans nervous system, which together implement a controllable hierarchical organization of behavior. Slow dynamics across brain and motor circuits drive upper-hierarchy motor states Fast dynamics in motor circuits drive lower-hierarchy movements within these states Slower dynamics tightly constrain the state and function of faster ones This rigid hierarchy nevertheless enables flexible behavioral control
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Affiliation(s)
- Harris S Kaplan
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Oriana Salazar Thula
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Niklas Khoss
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria.
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31
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Steuer Costa W, Van der Auwera P, Glock C, Liewald JF, Bach M, Schüler C, Wabnig S, Oranth A, Masurat F, Bringmann H, Schoofs L, Stelzer EHK, Fischer SC, Gottschalk A. A GABAergic and peptidergic sleep neuron as a locomotion stop neuron with compartmentalized Ca2+ dynamics. Nat Commun 2019; 10:4095. [PMID: 31506439 PMCID: PMC6736843 DOI: 10.1038/s41467-019-12098-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022] Open
Abstract
Animals must slow or halt locomotion to integrate sensory inputs or to change direction. In Caenorhabditis elegans, the GABAergic and peptidergic neuron RIS mediates developmentally timed quiescence. Here, we show RIS functions additionally as a locomotion stop neuron. RIS optogenetic stimulation caused acute and persistent inhibition of locomotion and pharyngeal pumping, phenotypes requiring FLP-11 neuropeptides and GABA. RIS photoactivation allows the animal to maintain its body posture by sustaining muscle tone, yet inactivating motor neuron oscillatory activity. During locomotion, RIS axonal Ca2+ signals revealed functional compartmentalization: Activity in the nerve ring process correlated with locomotion stop, while activity in a branch correlated with induced reversals. GABA was required to induce, and FLP-11 neuropeptides were required to sustain locomotion stop. RIS attenuates neuronal activity and inhibits movement, possibly enabling sensory integration and decision making, and exemplifies dual use of one cell across development in a compact nervous system.
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Affiliation(s)
- Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Petrus Van der Auwera
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Caspar Glock
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Max-Planck-Institute for Brain Research, Max-von-Laue-Strasse 4, 60438, Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Maximilian Bach
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Sebastian Wabnig
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,od green GmbH, Passauerstrasse 34, 4780, Schärding am Inn, Austria
| | - Alexandra Oranth
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Florentin Masurat
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Henrik Bringmann
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Department of Biology, University of Marburg, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Liliane Schoofs
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Ernst H K Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany
| | - Sabine C Fischer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany.,Center for Computational and Theoretical Biology (CCTB), University of Würzburg, Campus Hubland Nord 32, 97074, Würzburg, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany. .,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.
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32
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33
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Karbowski J. Deciphering neural circuits for Caenorhabditis elegans behavior by computations and perturbations to genome and connectome. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coisb.2018.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Abstract
The dynamics of complex systems generally include high-dimensional, nonstationary, and nonlinear behavior, all of which pose fundamental challenges to quantitative understanding. To address these difficulties, we detail an approach based on local linear models within windows determined adaptively from data. While the dynamics within each window are simple, consisting of exponential decay, growth, and oscillations, the collection of local parameters across all windows provides a principled characterization of the full time series. To explore the resulting model space, we develop a likelihood-based hierarchical clustering, and we examine the eigenvalues of the linear dynamics. We demonstrate our analysis with the Lorenz system undergoing stable spiral dynamics and in the standard chaotic regime. Applied to the posture dynamics of the nematode Caenorhabditis elegans, our approach identifies fine-grained behavioral states and model dynamics which fluctuate about an instability boundary, and we detail a bifurcation in a transition from forward to backward crawling. We analyze whole-brain imaging in C. elegans and show that global brain dynamics is damped away from the instability boundary by a decrease in oxygen concentration. We provide additional evidence for such near-critical dynamics from the analysis of electrocorticography in monkey and the imaging of a neural population from mouse visual cortex at single-cell resolution.
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Affiliation(s)
- Antonio C Costa
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, 1081HV Amsterdam, The Netherlands
| | - Tosif Ahamed
- Biological Physics Theory Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Greg J Stephens
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, 1081HV Amsterdam, The Netherlands;
- Biological Physics Theory Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
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35
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Tolstenkov O, Van der Auwera P, Steuer Costa W, Bazhanova O, Gemeinhardt TM, Bergs AC, Gottschalk A. Functionally asymmetric motor neurons contribute to coordinating locomotion of Caenorhabditis elegans. eLife 2018; 7:34997. [PMID: 30204083 PMCID: PMC6173582 DOI: 10.7554/elife.34997] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 09/09/2018] [Indexed: 12/11/2022] Open
Abstract
Locomotion circuits developed in simple animals, and circuit motifs further evolved in higher animals. To understand locomotion circuit motifs, they must be characterized in many models. The nematode Caenorhabditis elegans possesses one of the best-studied circuits for undulatory movement. Yet, for 1/6th of the cholinergic motor neurons (MNs), the AS MNs, functional information is unavailable. Ventral nerve cord (VNC) MNs coordinate undulations, in small circuits of complementary neurons innervating opposing muscles. AS MNs differ, as they innervate muscles and other MNs asymmetrically, without complementary partners. We characterized AS MNs by optogenetic, behavioral and imaging analyses. They generate asymmetric muscle activation, enabling navigation, and contribute to coordination of dorso-ventral undulation as well as anterio-posterior bending wave propagation. AS MN activity correlated with forward and backward locomotion, and they functionally connect to premotor interneurons (PINs) for both locomotion regimes. Electrical feedback from AS MNs via gap junctions may affect only backward PINs.
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Affiliation(s)
- Oleg Tolstenkov
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany.,Cluster of Excellence Frankfurt Macromolecular Complexes, Goethe University, Frankfurt, Germany
| | - Petrus Van der Auwera
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany.,Department of Biology, Functional Genomics and Proteomics Unit, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Olga Bazhanova
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
| | - Tim M Gemeinhardt
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Amelie Cf Bergs
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany.,International Max Planck Research School in Structure and Function of Biological Membranes, Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany.,Cluster of Excellence Frankfurt Macromolecular Complexes, Goethe University, Frankfurt, Germany
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36
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Izquierdo EJ, Beer RD. From head to tail: a neuromechanical model of forward locomotion in Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170374. [PMID: 30201838 PMCID: PMC6158225 DOI: 10.1098/rstb.2017.0374] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2018] [Indexed: 12/16/2022] Open
Abstract
With 302 neurons and a near-complete reconstruction of the neural and muscle anatomy at the cellular level, Caenorhabditis elegans is an ideal candidate organism to study the neuromechanical basis of behaviour. Yet despite the breadth of knowledge about the neurobiology, anatomy and physics of C. elegans, there are still a number of unanswered questions about one of its most basic and fundamental behaviours: forward locomotion. How the rhythmic pattern is generated and propagated along the body is not yet well understood. We report on the development and analysis of a model of forward locomotion that integrates the neuroanatomy, neurophysiology and body mechanics of the worm. Our model is motivated by experimental analysis of the structure of the ventral cord circuitry and the effect of local body curvature on nearby motoneurons. We developed a neuroanatomically grounded model of the head motoneuron circuit and the ventral nerve cord circuit. We integrated the neural model with an existing biomechanical model of the worm's body, with updated musculature and stretch receptors. Unknown parameters were evolved using an evolutionary algorithm to match the speed of the worm on agar. We performed 100 evolutionary runs and consistently found electrophysiological configurations that reproduced realistic control of forward movement. The ensemble of successful solutions reproduced key experimental observations that they were not designed to fit, including the wavelength and frequency of the propagating wave. Analysis of the ensemble revealed that head motoneurons SMD and RMD are sufficient to drive dorsoventral undulations in the head and neck and that short-range posteriorly directed proprioceptive feedback is sufficient to propagate the wave along the rest of the body.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Eduardo J Izquierdo
- Cognitive Science Program, School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN, USA
| | - Randall D Beer
- Cognitive Science Program, School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN, USA
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37
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Wen Q, Gao S, Zhen M. Caenorhabditis elegans excitatory ventral cord motor neurons derive rhythm for body undulation. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0370. [PMID: 30201835 DOI: 10.1098/rstb.2017.0370] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2018] [Indexed: 12/25/2022] Open
Abstract
The intrinsic oscillatory activity of central pattern generators underlies motor rhythm. We review and discuss recent findings that address the origin of Caenorhabditis elegans motor rhythm. These studies propose that the A- and mid-body B-class excitatory motor neurons at the ventral cord function as non-bursting intrinsic oscillators to underlie body undulation during reversal and forward movements, respectively. Proprioception entrains their intrinsic activities, allows phase-coupling between members of the same class motor neurons, and thereby facilitates directional propagation of undulations. Distinct pools of premotor interneurons project along the ventral nerve cord to innervate all members of the A- and B-class motor neurons, modulating their oscillations, as well as promoting their bi-directional coupling. The two motor sub-circuits, which consist of oscillators and descending inputs with distinct properties, form the structural base of dynamic rhythmicity and flexible partition of the forward and backward motor states. These results contribute to a continuous effort to establish a mechanistic and dynamic model of the C. elegans sensorimotor system. C. elegans exhibits rich sensorimotor functions despite a small neuron number. These findings implicate a circuit-level functional compression. By integrating the role of rhythm generation and proprioception into motor neurons, and the role of descending regulation of oscillators into premotor interneurons, this numerically simple nervous system can achieve a circuit infrastructure analogous to that of anatomically complex systems. C. elegans has manifested itself as a compact model to search for general principles of sensorimotor behaviours.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Quan Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, People's Republic of China .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Mei Zhen
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital; Department of Molecular Genetics, Department of Physiology, University of Toronto, Toronto, Ontario M5G 1XS, Canada
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38
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Palyanov A, Khayrulin S, Larson SD. Three-dimensional simulation of the Caenorhabditis elegans body and muscle cells in liquid and gel environments for behavioural analysis. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170376. [PMID: 30201840 PMCID: PMC6158221 DOI: 10.1098/rstb.2017.0376] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2018] [Indexed: 02/06/2023] Open
Abstract
To better understand how a nervous system controls the movements of an organism, we have created a three-dimensional computational biomechanical model of the Caenorhabditis elegans body based on real anatomical structure. The body model is created with a particle system-based simulation engine known as Sibernetic, which implements the smoothed particle-hydrodynamics algorithm. The model includes an elastic body-wall cuticle subject to hydrostatic pressure. This cuticle is then driven by body-wall muscle cells that contract and relax, whose positions and shape are mapped from C. elegans anatomy, and determined from light microscopy and electron micrograph data. We show that by using different muscle activation patterns, this model is capable of producing C. elegans-like behaviours, including crawling and swimming locomotion in environments with different viscosities, while fitting multiple additional known biomechanical properties of the animal. This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Andrey Palyanov
- Laboratory of Complex Systems Simulation, A.P. Ershov Institute of Informatics Systems, Acad. Lavrentiev ave. 6, 630090 Novosibirsk, Russia
- Laboratory of Structural Bioinformatics and Molecular Modeling, Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk, Russia
- OpenWorm Foundation, ℅ Software Freedom Law Center, 1995 Broadway, 17th Fl., New York, NY 10023, USA
| | - Sergey Khayrulin
- Laboratory of Complex Systems Simulation, A.P. Ershov Institute of Informatics Systems, Acad. Lavrentiev ave. 6, 630090 Novosibirsk, Russia
- Laboratory of Structural Bioinformatics and Molecular Modeling, Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk, Russia
- OpenWorm Foundation, ℅ Software Freedom Law Center, 1995 Broadway, 17th Fl., New York, NY 10023, USA
| | - Stephen D Larson
- OpenWorm Foundation, ℅ Software Freedom Law Center, 1995 Broadway, 17th Fl., New York, NY 10023, USA
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39
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Denham JE, Ranner T, Cohen N. Signatures of proprioceptive control in Caenorhabditis elegans locomotion. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2018.0208. [PMID: 30201846 DOI: 10.1098/rstb.2018.0208] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2018] [Indexed: 12/20/2022] Open
Abstract
Animal neuromechanics describes the coordinated self-propelled movement of a body, subject to the combined effects of internal neural control and mechanical forces. Here we use a computational model to identify effects of neural and mechanical modulation on undulatory forward locomotion of Caenorhabditis elegans, with a focus on proprioceptively driven neural control. We reveal a fundamental relationship between body elasticity and environmental drag in determining the dynamics of the body and demonstrate the manifestation of this relationship in the context of proprioceptively driven control. By considering characteristics unique to proprioceptive neurons, we predict the signatures of internal gait modulation that contrast with the known signatures of externally or biomechanically modulated gait. We further show that proprioceptive feedback can suppress neuromechanical phase lags during undulatory locomotion, contrasting with well studied advancing phase lags that have long been a signature of centrally generated, feed-forward control.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Jack E Denham
- School of Computing, University of Leeds, Leeds LS2 9JT, UK
| | - Thomas Ranner
- School of Computing, University of Leeds, Leeds LS2 9JT, UK
| | - Netta Cohen
- School of Computing, University of Leeds, Leeds LS2 9JT, UK
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Olivares EO, Izquierdo EJ, Beer RD. Potential role of a ventral nerve cord central pattern generator in forward and backward locomotion in Caenorhabditis elegans. Netw Neurosci 2018; 2:323-343. [PMID: 30294702 PMCID: PMC6145852 DOI: 10.1162/netn_a_00036] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/06/2017] [Indexed: 01/03/2023] Open
Abstract
C. elegans locomotes in an undulatory fashion, generating thrust by propagating dorsoventral bends along its body. Although central pattern generators (CPGs) are typically involved in animal locomotion, their presence in C. elegans has been questioned, mainly because there has been no evident circuit that supports intrinsic network oscillations. With a fully reconstructed connectome, the question of whether it is possible to have a CPG in the ventral nerve cord (VNC) of C. elegans can be answered through computational models. We modeled a repeating neural unit based on segmentation analysis of the connectome. We then used an evolutionary algorithm to determine the unknown physiological parameters of each neuron so as to match the features of the neural traces of the worm during forward and backward locomotion. We performed 1,000 evolutionary runs and consistently found configurations of the neural circuit that produced oscillations matching the main characteristic observed in experimental recordings. In addition to providing an existence proof for the possibility of a CPG in the VNC, we suggest a series of testable hypotheses about its operation. More generally, we show the feasibility and fruitfulness of a methodology to study behavior based on a connectome, in the absence of complete neurophysiological details.
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Affiliation(s)
- Erick O Olivares
- Cognitive Science Program, Indiana University, Bloomington, IN, USA
| | | | - Randall D Beer
- Cognitive Science Program, Indiana University, Bloomington, IN, USA
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A sensory-motor neuron type mediates proprioceptive coordination of steering in C. elegans via two TRPC channels. PLoS Biol 2018; 16:e2004929. [PMID: 29883446 PMCID: PMC6010301 DOI: 10.1371/journal.pbio.2004929] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/20/2018] [Accepted: 05/24/2018] [Indexed: 11/25/2022] Open
Abstract
Animal locomotion is mediated by a sensory system referred to as proprioception. Defects in the proprioceptive coordination of locomotion result in uncontrolled and inefficient movements. However, the molecular mechanisms underlying proprioception are not fully understood. Here, we identify two transient receptor potential cation (TRPC) channels, trp-1 and trp-2, as necessary and sufficient for proprioceptive responses in C. elegans head steering locomotion. Both channels are expressed in the SMDD neurons, which are required and sufficient for head bending, and mediate coordinated head steering by sensing mechanical stretches due to the contraction of head muscle and orchestrating dorsal head muscle contractions. Moreover, the SMDD neurons play dual roles to sense muscle stretch as well as to control muscle contractions. These results demonstrate that distinct locomotion patterns require dynamic and homeostatic modulation of feedback signals between neurons and muscles. Proprioception provides the nervous system with feedback about body posture in animals and is essential for the generation of coherent locomotive behaviors, such as walking, running, or crawling. However, little is known about the identity of proprioceptive receptors that sense body movement to regulate locomotion and the extent to which proprioception modulates sensorimotor coordination. Here, we analyze the molecular mechanisms that control head steering locomotion of Caenorhabditis elegans. We show that this movement is regulated by the transient receptor potential cation (TRPC) channels TRP-1 and TRP-2 and the SMDD proprioceptive neurons. We observe that mutant animals for both channels are defective in head steering locomotion and that ectopic expression of TRP-1 or TPR-2 in a C. elegans chemosensory neuron confers head bending–dependent responses, suggesting roles for these channels in proprioception. We also find that SMDD neurons are both necessary and sufficient to generate head steering locomotion via the two channels. Moreover, we demonstrate that the proprioceptive system mediates locomotion coordination by desynchronizing activities in motor systems. We conclude that two TRPC channels in collaboration with the proprioceptive receptor SMDD neurons control head steering in worms during forward locomotion.
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Xu T, Huo J, Shao S, Po M, Kawano T, Lu Y, Wu M, Zhen M, Wen Q. Descending pathway facilitates undulatory wave propagation in Caenorhabditis elegans through gap junctions. Proc Natl Acad Sci U S A 2018; 115:E4493-E4502. [PMID: 29686107 PMCID: PMC5948959 DOI: 10.1073/pnas.1717022115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Descending signals from the brain play critical roles in controlling and modulating locomotion kinematics. In the Caenorhabditis elegans nervous system, descending AVB premotor interneurons exclusively form gap junctions with the B-type motor neurons that execute forward locomotion. We combined genetic analysis, optogenetic manipulation, calcium imaging, and computational modeling to elucidate the function of AVB-B gap junctions during forward locomotion. First, we found that some B-type motor neurons generate rhythmic activity, constituting distributed oscillators. Second, AVB premotor interneurons use their electric inputs to drive bifurcation of B-type motor neuron dynamics, triggering their transition from stationary to oscillatory activity. Third, proprioceptive couplings between neighboring B-type motor neurons entrain the frequency of body oscillators, forcing coherent bending wave propagation. Despite substantial anatomical differences between the motor circuits of C. elegans and higher model organisms, converging principles govern coordinated locomotion.
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Affiliation(s)
- Tianqi Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, 230027 Hefei, China
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, 230027 Hefei, China
| | - Jing Huo
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, 230027 Hefei, China
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, 230027 Hefei, China
| | - Shuai Shao
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, 230027 Hefei, China
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, 230027 Hefei, China
| | - Michelle Po
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Taizo Kawano
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Yangning Lu
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Min Wu
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X5, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Quan Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, 230027 Hefei, China;
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, 230027 Hefei, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
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