composed primarily of cholinergic neuron parabigeminal nucleus neuronames:482 DHBA:12312 BM:PBG nucleus parabigeminalis UMLS:C0262301 VHOG:0001701 MBA:874 BAMS:PBG Nucleus isthmi is present in the isthmus in most vertebrates. It is called the parabigeminal nucleus in mammals (reference 1); In sum, our results show that the origin of neurons of some tegmental hindbrain nuclei, namely, nucleus isthmi/superior reticular nucleus and secondary gustatory/viscerosensory nucleus is in the URL (upper rhombic lip), and that the temporal order of cell types produced by the URL and their developmental program are conserved among vertebrate species (reference 2).[well established][VHOG] HBA:9111 parabigeminal nucleus (Bechterew) DMBA:16862 corpus parabigeminum UBERON:0002140 nucleus isthmi BIRNLEX:1007 parageminal nucleus EMAPA:35656 MA:0001074 Cholinergic cell group that is located ventral to the brachium of the inferior colliculus (in rat) and has reciprocal connectivity with the superior colliculus (Adapted from Paxinos, The rat central nervous system, 2nd ed, 1995, pg 865. in MA this is part of the tegmentum/brainstem FMA:72415 nucleus of midbrain tectum