In 10 experiments in rats projections of bulbar neurons to the ventrol
ateral medullary structures were first Found using the DiI-tracing tec
hnique. Pathways from the solitary tract nucleus and dorsal motor nucl
eus of the vagus predominate to the rostral site, and from a group of
vestibular nuclei oi the dorsal medulla - to the caudal site. It is co
ncluded that the ventrolateral medullary structures are a key relay li
nk in intrabulbar interactions.