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Wang H, Swore J, Sharma S, Szymanski JR, Yuste R, Daniel TL, Regnier M, Bosma MM, Fairhall AL. A complete biomechanical model of Hydra contractile behaviors, from neural drive to muscle to movement. Proc Natl Acad Sci U S A 2023; 120:e2210439120. [PMID: 36897982 PMCID: PMC10089167 DOI: 10.1073/pnas.2210439120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 01/03/2023] [Indexed: 03/12/2023] Open
Abstract
How does neural activity drive muscles to produce behavior? The recent development of genetic lines in Hydra that allow complete calcium imaging of both neuronal and muscle activity, as well as systematic machine learning quantification of behaviors, makes this small cnidarian an ideal model system to understand and model the complete transformation from neural firing to body movements. To achieve this, we have built a neuromechanical model of Hydra's fluid-filled hydrostatic skeleton, showing how drive by neuronal activity activates distinct patterns of muscle activity and body column biomechanics. Our model is based on experimental measurements of neuronal and muscle activity and assumes gap junctional coupling among muscle cells and calcium-dependent force generation by muscles. With these assumptions, we can robustly reproduce a basic set of Hydra's behaviors. We can further explain puzzling experimental observations, including the dual timescale kinetics observed in muscle activation and the engagement of ectodermal and endodermal muscles in different behaviors. This work delineates the spatiotemporal control space of Hydra movement and can serve as a template for future efforts to systematically decipher the transformations in the neural basis of behavior.
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Affiliation(s)
- Hengji Wang
- Department of Physics, University of Washington, Seattle, WA98195
- Computational Neuroscience Center, University of Washington, Seattle, WA98195
| | - Joshua Swore
- Department of Biology, University of Washington, Seattle, WA98195
| | - Shashank Sharma
- Department of Physiology and Biophysics, University of Washington, Seattle, WA98195
| | - John R. Szymanski
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY10027
- Marine Biological Laboratory, Woods Hole, MA02543
| | - Rafael Yuste
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY10027
- Marine Biological Laboratory, Woods Hole, MA02543
| | - Thomas L. Daniel
- Department of Biology, University of Washington, Seattle, WA98195
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA98195
| | - Martha M. Bosma
- Department of Biology, University of Washington, Seattle, WA98195
| | - Adrienne L. Fairhall
- Department of Physics, University of Washington, Seattle, WA98195
- Computational Neuroscience Center, University of Washington, Seattle, WA98195
- Department of Physiology and Biophysics, University of Washington, Seattle, WA98195
- Marine Biological Laboratory, Woods Hole, MA02543
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