The term rostral pontine reticular nucleus refers to the largest cellular component of the pontine reticular formation ( Carpenter-1983 ). Identified by Nissl stain, it is variously continuous across the midline or bounded medially by the raphe nuclei (classical) and the tectospinal tract. It is bounded ventrally by the reticulotegmental nucleus, the medial lemniscus of the pons and associated pathways. Laterally it is bounded largely by the lateral lemniscus and dorsally by the ventral tegmental nucleus, the superior cerebellar peduncle of the pons and the pedunculopontine nucleus. It is bounded rostrally by the ventral tegmental area and caudally by the caudal pontine reticular nucleus. It is found in the human ( Carpenter-1983 ), the macaque ( Paxinos-2009a ), the rat ( Swanson-2004 ) and the mouse ( Hof-2000 ). Functionally it is part of the behavioral state system ( Swanson-2004 ).