Hindlimb splitbelt treadmill walking of a rat based on a neuromusculoskeletal model

In this study, we conducted computer simulation of splitbelt treadmill walking by the hindlimbs of a rat based on a neuromusculoskeletal model. We developed the skeletal model based on anatomical data and constructed the nervous system model for locomotion based on the physiological findings of muscle synergy, central pattern generator, and sensory regulation by phase resetting. Our simulation results show that even in asymmetric environment due to the speed discrepancy between the left and right belts of a splitbelt treadmill, the rat model produced stable walking. The sensory regulation model contributed to generation of adaptive splitbelt treadmill walking while inducing the modulation of locomotion parameters, such as relative phase between the legs and duty factors, as observed in splitbelt treadmill walking of humans and animals. This helps understanding of the adaptation mechanism in locomotion through dynamic interactions among the nervous system, the musculoskeletal system, and the environment.