The Features of Synergetic Interaction of Lower Extremities’ Skeletal Muscles under the Spinal Cord Electrical Stimulation

Abstract

The aim of the work was to study the neural basis of the synergetic interaction of the lower extremities’ skeletal muscles during locomotor activity. It was supposed to determine the relationship of the locomotor-related neuronal networks with the centers regulating the spatiotemporal modes of muscle interaction in the structure of the step cycle and its periods. The subjects walked the treadmill both, under normal conditions and during spinal cord percutaneous electrical stimulation. The parameters of the synergies extracted using the principal component method were analyzed. The reorganization of neuronal activity of spinal locomotor-related networks, similar to adaptive processes that compensate for motor deficits in people with pathologies of the nervous system, has been revealed. Percutaneous electrical stimulation changed the reciprocal relations of bilateral lower extremities muscles in the structure of synergetic modules, mainly during the swing phase. The synergy structure demonstrated combined temporal profiles with several peaks of activity. During stimulation, the formation of a basic profile with a clear outline of the main fluctuations was revealed. The spatiotemporal structure of muscle synergy patterns during stance phase turned out to be more stable, which is probably due to an increase in afferentation from the foot support-sensetive zones, which creates optimal conditions for initiating the central generators of locomotor pattern.