part of synaptic neuropil subdomain mushroom body vertical lobelet fly_anatomy.ontology alpha p lobe Protrusions in the alpha accessory calyx layer (posterior, alpha-p) in the vertical lobe, formed by the fibers of the alpha/beta posterior Kenyon cells. FBbt:00045014 mushroom body alpha accessory calyx fibers VFB:FBbt_00045014 mushroom body neuropil subdivision mushroom body alpha lobe posterior layer