The term raphe nuclei (histological) (RPHhis) denotes a composite substructure that includes nuclei in the midline of the reticular formation (histological) of the upper cerebrospinal trunk extending from the caudal medulla to the midbrain. It includes the raphe nuclei of the medulla ( raphe magnus nucleus, raphe obscurus nucleus and raphe pallidus nucleus); the pontine raphe nucleus and the inferior central nucleus of the pontine reticular formation and the dorsal raphe nucleus and the median raphe nucleus of the midbrain reticular formation ( Carpenter-1983 ). Recent authors include the caudal linear nucleus of the raphe ( Hornung-2012 ) or both the caudal and the rostral linear nucleus of the raphe ( Paxinos-2012 ). All of the nuclei except the rostral linear nucleus overlap the serotonergic cell groups ( Hornung-2012 ). They are found in the human ( Paxinos-2012 ), the macaque ( Paxinos-2009a ), the rat ( Paxinos-2009b ) and the mouse ( Franklin-2008 ). See also raphe nuclei (functional).