Electrophysiological mapping of sympathetic nuclei in the L2 and L3 segments of the spinal cord.

The spinal sympathetic preganglionic nuclei were mapped using antidromic field potential analysis during electrical stimulation of L2 and L3 white rami. The spinal sympathetic nuclei were localized respectively in L2 and L3 segments of the lumbar cord as a narrow strip along craniocaudal axis of the spinal cord. The caudal and of each preganglionic sympathetic nucleus was localized caudally to the corresponding dorsal root entry (DRE). The cranial end of the nucleus in different experiments was localized at different levels along the corresponding DRE or cranial to the corresponding DRE. We suggest that neurones which send axons to a single white ramus form an anatomically separate sympathetic preganglionic nucleus in the lumbar spinal cord within one segment.