Recurrent inhibition model of cat gastrocnemius muscle

The purpose of this study was to construct a time domain model of cat medial gastrocnemus muscle with recurrent inhibition by Renshaw cells. The model consists of 300 motoneurons, 300 Renshaw cells and 300 muscle units. The membrane potential was calculated by convoluting EPSP (excitatory post-synaptic potential) caused by the descending command inputs, the AHP (after hyperpolarization) observed after the firing of the motoneurons and the IPSP (inhibitory post-synaptic potential) from Renshaw cells. When the membrane potential reaches the threshold potential, the motoneurons send an exitatory impulse to muscle units and Renshaw cells. The muscle units generate force and the Renshaw cells generate inhibitory burst pulse trains back to the motoneurons. The static firing rate of Renshaw cells of the proposed model was well approximated with the function which was investigated by physiological experiments.