The Rule of the Dependency Level of the Sensory Synergy in Recruiting Muscle Synergy

The concept of sensory and muscle synergies have reemerged in neuroscience as a possible mechanism adopted by the central nervous system (CNS) to deal with the complexity of the sensorimotor signaling in advanced mammals. Many studies have proposed various strategies to extract and deal with such as synergies: 1) to gain a deep insight into the neuromuscular system in human, and 2) to reconstruct robust neuro-base rehabilitation techniques for stroke patients. This study is a part of a series of studies that aim to build an automated neurorehabilitation tracking system based on understanding the link between the sensory synergy (SS) and the muscle synergy (MS). More precisely, here we are exploring the underlying mechanisms of how the CNS relies on SS feedback to recruit the proper MS when executing a certain movement. This study is derived from experimental analysis of automatic posture responses to the lateral ground perturbations of seven healthy subjects with various balance abilities. Results reveal that the dependency level among the calculated joint-acceleration-based SS are likely to be a key point for tuning the muscle synergy to ensure the quality of the resulting movement.