Dorsal root reflexes from a left L5 filament. A representative strand shows that DRRs can be recorded from the central stump of the dorsal root (L5) while the L4 central stump is stimulated (A). Each vertical line indicates a DRR. In this strand, about 4 fibers show DRR activity, based on their amplitudes and shapes. The horizontal line indicates the duration of electrical stimulation (20 V, 5 Hz, 0.5 ms for 5 min). During stimulation, an obvious increase of DRRs is demonstrated, which is summarized in (C). An expanded trace is shown in B. *: p < 0.05.