The term lateral reticular nucleus proper refers to the largest component of the lateral reticular nucleus as identified by multiple stains. Part of the medullary reticular formation, it is found in the human ( Paxinos-2012 ), the macaque ( Paxinos-2009a ), the rat ( Paxinos-2009b ), and the mouse ( Franklin-2008 ). Two other components in the primates and the rat are the parvicellular part of the lateral reticular nucleus and the subtrigeminal part of the lateral reticular nucleus. The mouse has one other part, the parvicellular part of the lateral reticular nucleus ( Franklin-2008 ).