Extracellular antidromic and orthodromic responses of the salivatory neurons in the medulla oblongata which send preganglionic parasympathetic fibers to the submandibular gland were recorded in rabbits. The mean of conduction time from the subnucleus caudalis of the spinal trigeminal nucleus to the salivatory neurons was within a range of 4.8-6.4 msec, suggesting oligosynaptic but not monosynaptic connections between the first order trigeminal sensory nucleus and the salivatory neurons.