Generation of signals controlling the temporal organization of motoneurons' activity during locomotor movements:...

A neuronal net providing signals controlling the temporal organization of activity of individual motoneurons’ pools of one limb during locomotor movements is proposed. The net was constructed from analog models of neurons. It was assumed that the system is a hierarchical one. The net of lower level corresponded to the net of motoneurons, Renshaw cells and Ia interneurons. The higher level was supposed to be a cyclic generator determining the general pattern of coordination of limbs by means of appropriate timing of muscles. The conditions for generation of signals activating one as well as two joint muscles were found. To obtain the pattern corresponding to the pattern of muscle coordination, two kinds of influence were necessary: tonic and phasic. This made possible the independent control of muscle activity duration and the moments of their on and off switching.