Tuning of the spinal generators: modelling study.

To solve the problem of minimalization of the control (tuning) signals to the spinal generator organizing the locomotor pattern of limb movements a model of neuronal net, forming a part of spinal generator which coordinates limb movements was designed. The model net was constructed of analog inhibitory neurons. The model was verified on the basis of data obtained in electrophysiological and behavioral investigations of cat locomotion. The results support the hypothesis that limb coordination is due to supraspinal influences determining the level of excitation and the way of coupling of spinal subsystems. The control of model’s acting can be achieved by tonic excitatory signals only. It is proposed that the spinal structures taking part in a process of limb coordination form two subsystems, one generating the general cycle of limb movement and the second one controlling the activity of individual muscles.