An optimality principle for locomotor central pattern generators

Abstract Two types of neural circuits contribute to legged locomotion: central pattern generators (CPGs) that produce rhythmic motor commands (even in the absence of feedback, termed “fictive locomotion”), and reflex circuits driven by sensory feedback. Each circuit alone serves a clear purpose, and...

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Autores principales: Hansol X. Ryu, Arthur D. Kuo
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Lenguaje:EN
Publicado: Nature Portfolio 2021
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Acceso en línea:https://doaj.org/article/24b444faf5484b3386d5f2551449109d
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spelling oai:doaj.org-article:24b444faf5484b3386d5f2551449109d2021-12-02T17:45:20ZAn optimality principle for locomotor central pattern generators10.1038/s41598-021-91714-12045-2322https://doaj.org/article/24b444faf5484b3386d5f2551449109d2021-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-91714-1https://doaj.org/toc/2045-2322Abstract Two types of neural circuits contribute to legged locomotion: central pattern generators (CPGs) that produce rhythmic motor commands (even in the absence of feedback, termed “fictive locomotion”), and reflex circuits driven by sensory feedback. Each circuit alone serves a clear purpose, and the two together are understood to cooperate during normal locomotion. The difficulty is in explaining their relative balance objectively within a control model, as there are infinite combinations that could produce the same nominal motor pattern. Here we propose that optimization in the presence of uncertainty can explain how the circuits should best be combined for locomotion. The key is to re-interpret the CPG in the context of state estimator-based control: an internal model of the limbs that predicts their state, using sensory feedback to optimally balance competing effects of environmental and sensory uncertainties. We demonstrate use of optimally predicted state to drive a simple model of bipedal, dynamic walking, which thus yields minimal energetic cost of transport and best stability. The internal model may be implemented with neural circuitry compatible with classic CPG models, except with neural parameters determined by optimal estimation principles. Fictive locomotion also emerges, but as a side effect of estimator dynamics rather than an explicit internal rhythm. Uncertainty could be key to shaping CPG behavior and governing optimal use of feedback.Hansol X. RyuArthur D. KuoNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-18 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Hansol X. Ryu
Arthur D. Kuo
An optimality principle for locomotor central pattern generators
description Abstract Two types of neural circuits contribute to legged locomotion: central pattern generators (CPGs) that produce rhythmic motor commands (even in the absence of feedback, termed “fictive locomotion”), and reflex circuits driven by sensory feedback. Each circuit alone serves a clear purpose, and the two together are understood to cooperate during normal locomotion. The difficulty is in explaining their relative balance objectively within a control model, as there are infinite combinations that could produce the same nominal motor pattern. Here we propose that optimization in the presence of uncertainty can explain how the circuits should best be combined for locomotion. The key is to re-interpret the CPG in the context of state estimator-based control: an internal model of the limbs that predicts their state, using sensory feedback to optimally balance competing effects of environmental and sensory uncertainties. We demonstrate use of optimally predicted state to drive a simple model of bipedal, dynamic walking, which thus yields minimal energetic cost of transport and best stability. The internal model may be implemented with neural circuitry compatible with classic CPG models, except with neural parameters determined by optimal estimation principles. Fictive locomotion also emerges, but as a side effect of estimator dynamics rather than an explicit internal rhythm. Uncertainty could be key to shaping CPG behavior and governing optimal use of feedback.
format article
author Hansol X. Ryu
Arthur D. Kuo
author_facet Hansol X. Ryu
Arthur D. Kuo
author_sort Hansol X. Ryu
title An optimality principle for locomotor central pattern generators
title_short An optimality principle for locomotor central pattern generators
title_full An optimality principle for locomotor central pattern generators
title_fullStr An optimality principle for locomotor central pattern generators
title_full_unstemmed An optimality principle for locomotor central pattern generators
title_sort optimality principle for locomotor central pattern generators
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/24b444faf5484b3386d5f2551449109d
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