develops from has synaptic IO in region medulla transmedullary neuron transmedullary Y neuron FBbt:00003817 fly_anatomy.ontology TmY VFB:FBbt_00003817 An intrinsic columnar neuron of the optic lobe whose cell body lies in the distal cortex of the medulla and that arborizes in the medulla and branches in the second optic chiasm with one branch innervating the lobula and the other the lobula plate. TmY lobula plate immature transmedullary Y neuron