Figure 8.

Topographical maps versus trajectories of the center of mass for traveling electrical waves in the cat spinal cord. A, Topographical maps calculated for 10 successive times as is indicated by the vertical lines in B. B, Recordings obtained with the multielectrode array during two cycles of extension–flexion. The red and blue circles indicate that there are positive and negative waves preceding the beginning of the extensor (MG) and flexor (TA) bursts. C, D, Superimposed trajectories in the conditions indicated (data obtained from 22 cats; each color represents the trajectory of a different cat). Note that, during the negative and positive phases of the traveling wave, the trajectories follow a rostrocaudal direction. Additionally, the ipsilateral (left or right) scratching was associated with ipsilateral trajectories of traveling waves, which resembled strips across the longitudinal axis of the spinal cord, from L4 to S1. The sinusoidal CDP signals were refiltered at 1–70 Hz bandpass.