Reticulospinal neurons (RSNs) in the medial pontomedullary reticular formation have been suggested as being the relay station of the disynaptic pathways from the superior colliculus and the cerebral cortex to the dorsal neck motoneurons. A unilateral lesion of the nucleus reticularis pontis caudalis (NRPC) and the rostral part of the nucleus reticularis gigantocellularis (NRG) produced by kainic acid injection resulted in a severe impairment of ipsiversive orienting movements of the eyes and head in the horizontal direction. This suggests that this region plays a vital role in controlling horizontal orienting movement. However, vertical orienting movement appeared to be unfazed after the lesion, suggesting that it is regulated by separate pathways.