lobula layer 1 FBbt:00040012 lobula layer Lo1 T5 layer Layer of the lobula that abuts the second optic chiasm. It is defined by the bushy arborizations of the T5 neurons, and by the terminal arborizations of transmedullary neuron Tm1 and Tm9. FBbt:00003853 VFB:FBbt_00003853 fly_anatomy.ontology lobula layer