AFFERENT RELATIONS OF INFERIOR OLIVARY NUCLEUS: IV. LATERAL CERVICAL NUCLEUS AS SITE OF FINAL RELAY TO INFERIOR OLIVE IN CAT

Abstract

Electrophysiological evidence indicates that the lateral cervical nucleus (LCN) is the site of the upper spinal relay between the dorsal spino-olivary tract and the tertiary fibers which cross to innervate the opposite inferior olive. The relative time relations, forms and magnitudes of the responses produced in the LCN and contralateral olive by stimulation of various peripheral pathways are similar, the response in the LCN always preceding that in the olive. The characteristic low spinal origin of the hindlimb component of the spinoolivary tract is also shared by the activators of the LCN. Stimulation of the contralateral olive causes antidromic activity in the LCN at the same sites as those activated by ascending spinal impulses. The relay for the dorsal spino-olivary tract to the LCN has a synaptic delay of 0.5 to 1.0 msec.