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Investigating the roles of reflexes and central pattern generators in the control and modulation of human locomotion using a physiologically plausible neuromechanical model
Journal article   Open access   Peer reviewed

Investigating the roles of reflexes and central pattern generators in the control and modulation of human locomotion using a physiologically plausible neuromechanical model

Andrea Di Russo, Dimitar Stanev, Anushree Sabnis, Simon M Danner, Jessica Ausborn, Stéphane Armand and Auke Ijspeert
Journal of neural engineering
27 Sep 2023
DOI: https://doi.org/10.1088/1741-2552/acfdcc
Featured in Collection :   UN Sustainable Development Goals @ Drexel
url
https://doi.org/10.1088/1741-2552/acfdccView
Published, Version of Record (VoR)CC BY V4.0,  Open

Abstract

Abstract Objective: Studying the neural components regulating movement in human locomotion is obstructed by the inability to perform invasive experimental recording in the human neural circuits. Neuromechanical simulations can provide insights by modeling the locomotor circuits. Past neuromechanical models proposed control of locomotion either driven by central pattern generators (CPGs) with simple sensory commands or by a purely reflex-based network regulated by state-machine mechanisms, which activate and deactivate reflexes depending on the detected gait cycle phases. However, the physiological interpretation of these state machines remains unclear. Here, we present a physiologically plausible model to investigate spinal control and modulation of human locomotion. Approach: We propose a bio-inspired controller composed of two coupled central pattern generators (CPGs) that produce the rhythm and pattern, and a reflex-based network simulating low-level reflex pathways and Renshaw cells. This reflex network is based on leaky-integration neurons, and the whole system does not rely on changing reflex gains according to the gait cycle state. The musculoskeletal model is composed of a skeletal structure and 9 muscles per leg generating movement in sagittal plane. Main results: Optimizing the open parameters for effort minimization and stability, human kinematics and muscle activation naturally emerged. Furthermore, when CPGs were not activated, periodic motion could not be achieved through optimization, suggesting the necessity of this component to generate rhythmic behavior without a state machine mechanism regulating reflex activation. The controller could reproduce ranges of speeds from 0.3 to 1.9 m/s. The results showed that the net influence of feedback on motoneurons during perturbed locomotion is predominantly inhibitory and that the CPGs provide the timing of motoneurons’ activation by exciting or inhibiting muscles in specific gait phases. Significance: The proposed bio-inspired controller could contribute to our understanding of locomotor circuits of the intact spinal cord and could be used to study neuromotor disorders.

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29 Record Views
11 citations in Web of Science
7 citations in Scopus

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UN Sustainable Development Goals (SDGs)

This publication has contributed to the advancement of the following goals:

#3 Good Health and Well-Being

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Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Engineering, Biomedical
Neurosciences
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