develops from receives synaptic input in region sends synaptic output to region receives synaptic input from neuron sends synaptic output to cell GABA-Chol neuron lamina monopolar neuron L2 T5 neuron centrifugal neuron C3 medulla layer M2 medulla layer M3 medulla layer M4 medulla layer M9 transmedullary neuron Tm4 Tm4 VFB:FBbt_00003792 FlyBrain_NDB:10155 Tm4 fly_anatomy.ontology Transmedullary narrow field neuron that terminates in lobula layers 1, 2 and 4 with bleb-type arborizations, and with fine arborizations in layer 3. It displays fine arborizations in medulla layers M2, M3, M4 and M9, and has bleb-type arborizations in layers M2, M4, and M9 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). In the medulla, receives input from lamina monopolar neuron L2 and centrifugal neuron C3 (Takemura et al., 2013). In lobula layer 1, it outputs to T5 neurons (Shinomiya et al., 2014). It seems to be capable of both cholinergic and GABAergic neurotransmission. There is usually one of these cells per optic column (Nern et al., 2025). FBbt:00003792 https://cdn.ncbi.nlm.nih.gov/pmc/blobs/bae0/7069908/ef7abe34662d/359_2019_1375_Fig2_HTML.jpg The acetylcholine neurotransmitter was assessed by co-labelling cells with a Cha-GAL4.7.4 driver (FBtp0014830) and an anti-ChAT antibody (Varija Raghu et al., 2011), and by scRNAseq detection of choline acetyltransferase (FBgn0000303) and vesicular acetylcholine transporter (FBgn0270928) expression (Davis et al., 2020). The GABA neurotransmitter was assessed by the intersection of the expression of the VGAT-GAL4 driver (FBtp0069181) and an antibody against GABA (Raghu et al., 2013). Pre- versus postsynaptic innervation judged by scoring of terminal morphology from figures in Fischbach and Dittrich (1989) as assessed by FlyBrain Neuron DB. Connectivity in the medulla was extrapolated from serial EM from 7 columns (Takemura et al., 2013). Connectivity in the lobula was assessed by serial section electron microscopy of a single column (Shinomiya et al., 2014). lobula layer 1 lobula layer 2 lobula layer 3 lobula layer 4 narrow field transmedullary neuron Notch ON hemilineage secondary neuron immature transmedullary neuron Tm4 adult cholinergic neuron adult GABAergic neuron