has fasciculating neuron projection innervates protocerebral bridge glomerulus 4 protocerebral bridge glomerulus 5 commissure pb-fb tract pb-fb tract Y FBbt:00007505 VFB:FBbt_00007505 fly_anatomy.ontology Tract of the adult central complex that contains columnar neurons of lineage DM2 (neuroblast Y) and innervates the third most lateral two protocerebral bridge glomeruli (4 and 5) and the central and contralateral medial fan-shaped body (Hanesch et al., 1989; Boyan et al., 2017). adult DM2 lineage neuron