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Gutiérrez-Ibáñez C, Wylie DR, Altshuler DL. From the eye to the wing: neural circuits for transforming optic flow into motor output in avian flight. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:839-854. [PMID: 37542566 DOI: 10.1007/s00359-023-01663-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/07/2023]
Abstract
Avian flight is guided by optic flow-the movement across the retina of images of surfaces and edges in the environment due to self-motion. In all vertebrates, there is a short pathway for optic flow information to reach pre-motor areas: retinal-recipient regions in the midbrain encode optic flow, which is then sent to the cerebellum. One well-known role for optic flow pathways to the cerebellum is the control of stabilizing eye movements (the optokinetic response). However, the role of this pathway in controlling locomotion is less well understood. Electrophysiological and tract tracing studies are revealing the functional connectivity of a more elaborate circuit through the avian cerebellum, which integrates optic flow with other sensory signals. Here we review the research supporting this framework and identify the cerebellar output centres, the lateral (CbL) and medial (CbM) cerebellar nuclei, as two key nodes with potentially distinct roles in flight control. The CbM receives bilateral optic flow information and projects to sites in the brainstem that suggest a primary role for flight control over time, such as during forward flight. The CbL receives monocular optic flow and other types of visual information. This site provides feedback to sensory areas throughout the brain and has a strong projection the nucleus ruber, which is known to have a dominant role in forelimb muscle control. This arrangement suggests primary roles for the CbL in the control of wing morphing and for rapid maneuvers.
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Affiliation(s)
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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Wang Y, He Q, Wang Z, Zhang S, Li C, Wang Z, Park YL, Cai S. Liquid Crystal Elastomer Based Dexterous Artificial Motor Unit. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211283. [PMID: 36806211 DOI: 10.1002/adma.202211283] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/18/2023] [Indexed: 05/17/2023]
Abstract
Despite the great advancement in designing diverse soft robots, they are not yet as dexterous as animals in many aspects. One challenge is that they still lack the compact design of an artificial motor unit with a great comprehensive performance that can be conveniently fabricated, although many recently developed artificial muscles have shown excellent properties in one or two aspects. Herein, an artificial motor unit is developed based on gold-coated ultrathin liquid crystal elastomer (LCE) film. Subject to a voltage, Joule heating generated by the gold film increases the temperature of the LCE film underneath and causes it to contract. Due to the small thermal inertial and electrically controlling method of the ultrathin LCE structure, its cyclic actuation speed is fast and controllable. It is shown that under electrical stimulation, the actuation strain of the LCE-based motor unit reaches 45%, the strain rate reaches 750%/s, and the output power density is as high as 1360 W kg-1 . It is further demonstrated that the LCE-based motor unit behaves like an actuator, a brake, or a nonlinear spring on demand, analogous to most animal muscles. Finally, as a proof-of-concept, multiple highly dexterous artificial neuromuscular systems are demonstrated using the LCE-based motor unit.
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Affiliation(s)
- Yang Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Qiguang He
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Zhijian Wang
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Shengjia Zhang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Chenghai Li
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Zijun Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yong-Lae Park
- Department of Mechanical Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Shengqiang Cai
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, 92093, USA
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Leal PBC, Cabral-Seanez M, Baliga VB, Altshuler DL, Hartl DJ. Phase transformation-driven artificial muscle mimics the multifunctionality of avian wing muscle. J R Soc Interface 2021; 18:20201042. [PMID: 34727709 PMCID: PMC8564628 DOI: 10.1098/rsif.2020.1042] [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: 12/23/2020] [Accepted: 10/12/2021] [Indexed: 11/12/2022] Open
Abstract
Skeletal muscle provides a compact solution for performing multiple tasks under diverse operational conditions, a capability lacking in many current engineered systems. Here, we evaluate if shape memory alloy (SMA) components can serve as artificial muscles with tunable mechanical performance. We experimentally impose cyclic stimuli, electric and mechanical, to an SMA wire and demonstrate that this material can mimic the response of the avian humerotriceps, a skeletal muscle that acts in the dynamic control of wing shapes. We next numerically evaluate the feasibility of using SMA springs as artificial leg muscles for a bipedal walking robot. Altering the phase offset between mechanical and electrical stimuli was sufficient for both synthetic and natural muscle to shift between actuation, braking and spring-like behaviour.
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Affiliation(s)
- Pedro B. C. Leal
- Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Marcela Cabral-Seanez
- Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Vikram B. Baliga
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Douglas L. Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Darren J. Hartl
- Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA
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Knight K. Muscles brake and bend joints to shape wings. J Exp Biol 2019. [DOI: 10.1242/jeb.204214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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