Figure 3.

Electroneurographic activity in the left (black) and in the right (gray) hindlimb in a cat with a chronic left hemisection (3 weeks). A, There were bursts of activity in all five nerves in the left hindlimb and weaker bursts of activity in two nerves (both flexors) in the right hindlimb. B, During a period of inactivity, trains of stimuli in the sciatic nerve (50 pulses, 200 Hz, 5.0 T) were given to trigger an episode of rhythmic activities. After the stimuli, clear bursts of activity (arrows) were generated in PBSt and two extensor nerves (MG and LGS) on the right side, yet these nerves were silent during the ensuing episode of fictive locomotion (as in A). C, In the same cat, fictive locomotion occurred after an acute spinalization with injection of clonidine. There were rhythmic bursts in four nerves in the left hindlimb and in three nerves in the right hindlimb (two extensors and one flexor). Under the episode of fictive locomotion in A and C is a plot showing the linear relationship between the cycle duration and the phase duration with the same outline as Figure 1.