Computer Simulation of Stepping in the Hind Legs of the Cat: An Examination of Mechanisms Regulating the Stance-to-Swing Transition
Open Access
- 1 December 2005
- journal article
- research article
- Published by American Physiological Society in Journal of Neurophysiology
- Vol. 94 (6), 4256-4268
- https://doi.org/10.1152/jn.00065.2005
Abstract
Physiological studies in walking cats have indicated that two sensory signals are involved in terminating stance in the hind legs: one related to unloading of the leg and the other to hip extension. To study the relative importance of these two signals, we developed a three-dimensional computer simulation of the cat hind legs in which the timing of the swing-to-stance transition was controlled by signals related to the force in ankle extensor muscles, the angle at the hip joint, or a combination of both. Even in the absence of direct coupling between the controllers for each leg, stable stepping was easily obtained using either a combination of ankle force and hip position signals or the ankle force signal alone. Stable walking did not occur when the hip position signal was used alone. Coupling the two controllers by mutual inhibition restored stability, but it did not restore the correct timing of stepping of the two hind legs. Small perturbations applied during the swing phase altered the movement of the contralateral leg in a manner that tended to maintain alternating stepping when the ankle force signal was included but tended to shift coordination away from alternating when the hip position signal was used alone. We conclude that coordination of stepping of the hind legs depends critically on load-sensitive signals from each leg and that mechanical linkages between the legs, mediated by these signals, play a significant role in establishing the alternating gait.Keywords
This publication has 32 references indexed in Scilit:
- Contribution of Force Feedback to Ankle Extensor Activity in Decerebrate Walking CatsJournal of Neurophysiology, 2004
- Modeling the spinal cord neural circuitry controlling cat hindlimb movement during locomotionNeurocomputing, 2003
- Adaptive Dynamic Walking of a Quadruped Robot on Irregular Terrain Based on Biological ConceptsThe International Journal of Robotics Research, 2003
- Parallel Complementary Strategies for Implementing Biological Principles into Mobile RobotsThe International Journal of Robotics Research, 2003
- Projection patterns of commissural interneurons in the lumbar spinal cord of the neonatal ratJournal of Comparative Neurology, 2002
- Spinal circuitry of sensorimotor control of locomotionJournal Of Physiology-London, 2001
- The initiation of the swing phase in human infant stepping: importance of hip position and leg loadingJournal Of Physiology-London, 2000
- Modulation of limb dynamics in the swing phase of locomotionJournal of Biomechanics, 1985
- Locomotion in the cat: Basic programmes of movementBrain Research, 1975
- The cat step cycle: Hind limb joint angles and muscle lengths during unrestrained locomotionJournal of Morphology, 1973