develops from receives synaptic input in region sends synaptic output to region medulla layer M5 medulla layer M6 distal medullary amacrine neuron distal medullary amacrine neuron Dm4 Dm4 Classified as columnar based on first stretch of main projection being limited to a single column, but as it then bends and projects along the plane of M5/M6 where it arborizes, this is clearly an edge case. Pre- versus postsynaptic innervation were judged by scoring of terminal morphology from figures in Fischbach and Dittrich (1989) as assessed by FlyBrain Neuron DB. FBbt:00003771 Distal medullary wide-field amacrine neuron whose cell body is located in the anterior region of the cell body rind of the medulla. The main neurite extends into M6, and then turns back to arborize in the boundary between M5 and M6, and in M3B, with mixed morphology arborizations. The arbor varies in shape between cells, covering around 21 columns, but with these areas tiling. It is located in a central position in the column, surrounded by the terminal of photoreceptors R7 and R8, with the cell boundaries following the column boundaries. There are around 40 Dm4 neurons per hemisphere. They are glutamatergic (Davis et al., 2020). FlyBrain_NDB:10084 VFB:FBbt_00003771 Dm4 fly_anatomy.ontology Notch OFF hemilineage secondary neuron immature distal medullary amacrine neuron Dm4 adult glutamatergic neuron optic lobe wide-field columnar neuron medulla sublayer M3B