Neuronal Basis of Stance Regulation: Interlimb Coordination and Antigravity Receptor Function

Publisher Summary This chapter discusses the two basic aspects of the neuronal control of bipedal stance and gait, namely, the interlimb coordination and the antigravity function of leg extensors. Regulation of bipedal stance and gait shows fundamental differences to that of quadrupedal locomotion, requiring specific neuronal mechanisms to maintain the body in an upright position. During stance and gait, both legs act in a cooperative manner as each limb affects the strength of muscle activation and time–space behavior of the other. There are indications that interlimb coordination is mediated by spinal interneuronal circuits that are themselves under supraspinal control. Proprioceptive reflexes involved in the maintenance of body equilibrium depend on the presence of contact forces opposing gravity. Extensor load receptors are thought to signal changes of the projection of the body's center of mass with respect to the feet. According to recent observations in the spinal cat, this afferent input probably arises from Golgi tendon organs and represents a newly discovered function of these receptors in the regulation of stance and gait.