Figure 5.

Motoneurone activities in the model and in the cat A, examples of population activities of flexor and extensor motoneurones and membrane potential traces of single motoneurones in the model. Activities of flexor and extensor populations are represented by the average histograms (top trace for Mn-F and fourth trace for Mn-E) and raster plots (second trace for Mn-F and fifth trace for Mn-E). In both raster plots, the lines correspond to single motoneurones arranged by neurone numbers from 1 to 20, and the dots in each line represent spikes. Membrane potentials of one flexor and one extensor motoneurone are shown in third and bottom traces, respectively, with action potentials truncated at the level of −10 mV. In this simulation, the MLR drive to RG-F (d_rg-f) was 0.52 and to RG-E (d_rg-e) 0.46. B, records during MLR-evoked fictive locomotion showing electroneurogram (ENG) activity of ankle (tibialis anterior, TA) and hip (sartorius, Sart) flexors, ankle (medial gastrocnemius, MG) and hip (semimembranosus combined with anterior biceps, SmAB) extensors, and simultaneous intracellular recordings from a Sart and an SmAB motoneurone.