Fig. 9.

Resetting the walking-like rhythm by reafferent input consequent to limb movement. A, Stimulation of the ventral root C3 by a train of 6 pulses of 40 Hz at 1.2× the motor threshold intensity modulated the cycle duration in a phase-dependent manner and partially reset the walking-like rhythm. B, Deafferentation by dorsal rhizotomy abolished the resetting effect of ventral root stimulation. The average of the mean cycle durations of the steps immediately before and after the stimulated cycle is shown as a horizontal line in A andB. C, Dorsal root cutting, per se, significantly affected the walking cadence. Cutting the C3 dorsal root shortened the cycle duration compared with the precutting control (Ctl), whereas cutting the C2 dorsal root prolonged the cycle duration. Cutting the C4 and C5 dorsal roots also shortened the cycle duration.