[Stepping movements caused by stimulation of the cat spinal cord dorsolateral funiculus]

Abstract

It has been demonstrated in experiments on mesencephalic cats that microstimulation of the dorsolateral funiculus (DLF) at any level (from C1 to L1) elicited stepping movements in the ipsilateral hind limb. The lesion of the DLF at the C2--C3 level interfered with provocation of the stepping from the more rostral part of the DLF. However, stimulation caudal to the lesion remained effective. Stimulation of the DLF at the C5--Th3 did not prevent the stepping from L1, whereas that at the Th13 level made L1 ineffective despite the fact that the stepping was provoked by stimulation at the Th12 level. After lesion of the DLF at the two sites (C2 and L1 levels) stimulation at any level (from C3 to Th13) continued provoking the stepping. However, after stimulation at the Th5 and L1 levels the lesion of an isolated DLF area appeared ineffective. The data obtained suggest that stimulation of the DLF can elicit the stepping of the hind limb through the propriospinal system, provided that the stimulated part of the DLF contains at least 8--12 intact segments.