Lumbosacral dorsal root terminations in the nucleus gracilis of the cat. Some observations on terminal degeneration in other medullary sensory nuclei.

Abstract

Following lumbosacral dorsal rhizotomies (L1, L5, L6 and S1), fiber degeneration could be traced throughout three rostro‐caudal regions of nucleus gracilis by utilizing the Nauta method. In rostral region, fiber degeneration was less dense and localized with greater intersegmental overlap than in middle region, where roots terminated in fairly specific cell clusters. Little could be stated about the caudal region because of sparsity of terminal degeneration. Fiber degeneration in rostral region appeared to be distributed primarily in the dendritic fields while that in the middle region terminated on both cell somata and dendrites. Overlap of dermatomes in periphery and centrally in nucleus p..