Wavelet analysis of rhythmic bursts produced in the lumbar segments of the spinal cord by stimulation of sacrocaudal afferents. A, Schematic illustration of the preparation and the surgical manipulations whose effects on the rhythm are analyzed. The isolated spinal cord preparation of the neonatal rat is shown in the experimental bath (frame). The rhythm is produced by stimulation of the Co1 dorsal root (Co1) and recorded from the left and right L2 ventral roots (LL2 and RL2 respectively). The lumbosacral junction at which the ventral funiculi were lesioned (scissors) is denoted by the red bar. The cross section of the spinal cord on the right shows the gray matter laminae (I–X) and the white matter funiculi. DF, DLF, LF, VLF and VF are the dorsal, dorsolateral, lateral, ventrolateral and ventral funiculi, respectively. B, Recordings of the rhythm produced by SCA stimulation from the left (L) and right (R) ventral roots of L2 before (Control), and following a bilateral VF cut (VF cut) at the lumbosacral junction. The lesioned funiculi are shown in red at the schematic cross section. C, The coherent power spectra of the rhythm before and after the bilateral VF lesion (Control and VF cut) are superimposed with the respective rectified data. The high-power regions of interest (ROIs) selected for further analysis are delineated with the white dotted lines, and the 3 consecutive epochs composing each ROI (I, II, and III) are marked by red lines. The stimulus trains are illustrated below each spectrum (trains). Circular plots of the mean left–right phase values and r-vectors (red arrows) at each of the three epochs within each ROI are shown on the lower left (Phase analysis, control and VF cut). The mean normalized frequency, coherence and normalized power during each epoch, before (black bars), and after (gray bars) the bilateral VF cut are superimposed with the respective SD on the lower right (Frequency/Coherence/Power analysis). Stimulus trains, Control and VF cut: 20 pulse, 1.3 Hz at 1.1T. Number of trains: 4 Control, 4 VF cut.