three major loci of methionine-enkephalin-immunoreactive cells were found : ( 1 ) the nucleus reticularis paragigantocellularis lateralis , at levels caudal to the facial nucleus , ( 2 ) the b3 cell group ( nucleus raphe magnus and the nucleus reticularis magnocellularis , pars alpha ) and the most rostral part of the b1 and b2 cell groups ( nuclei raphe pallidus and obscurus ) , ( 3 ) a dense cluster of cells that flanks the dorsal surface of the dorsal accessory olive ( referred to as the nucleus interfascicularis hypoglossi , pars dorsalis ) .
C1708726
loci
C0007634
cell