On the central generation of locomotion in the low spinal cat

Abstract

A central network of neurones in the spinal cord has been shown to produce a rhythmic motor output similar to locomotion after suppression of all afferent inflow. The experiments were performed mainly in acute spinal cats (th. 12), which had received DOPA i.v. and the monoamine oxidase inhibitor Nialamide. In some preparations all dorsal roots supplying the spinal cord were transected, in others phasic afferent activity was suppressed by curarization. The activity was recorded as neurograms from nerve filaments or as electromyograms. It is concluded that: alternating activity between flexors and extensors of foot, ankle, knee, and hip of one limb can still occur the duration of the flexor discharges vary less with the cycle duration than the extensor discharges different flexor muscles may retain individual patterns the activity at different joints can be dissociated there is at least one network for each limb the coordination between the two hindlimbs can be alternating as in walking or be more closely spaced as in galloping alternating activity in the ankle remains even when only segments L6, L7 and S1 are intact.