Lawf1 [FBbt_00003741]

Lawf1

ID: FBbt_00003741

A lamina wide-field neuron that has a main projection that ascends via the first optic chiasm into the lamina where it is restricted to a single column for most of its length before making wide-field arborizations in the distal lamina. These neurons also arborize on the distal surface of the medulla in a circular field of about 20 columns. Several linking fibers from this arborization descend into M4 where they form a wide arborization field covering about 30-40 columns (Fischbach and Dittrich, 1989; Morante and Desplan, 2008). In the lamina, it forms numerous presynaptic connections to lamina monopolar neuron L3 and lamina intrinsic (amacrine) neuron (Rivera-Alba et al., 2011).

Pre-synaptic terminals were assessed by labelling with a UAS-Synaptotagmin reporter (P{UAS-HA-syt} - FBtp0015803). The identification of dendrites and axons was done using a UAS-Dscam (P{UAS-Dscam.exon17.1.GFP} - FBtp0021447) or a UAS-tau (P{UAS-tau-lacZ.O} - FBtp0010033) reporter, respectively (Morante and Desplan, 2008). Cell connectivity in the lamina was determined by analysis of semi-automated EM reconstruction of 749 serial sections of 21 complete lamina cartridges. The number of synaptic connections for Lawf (presynaptic/postsynaptic) in a single lamina cartridge with each cell type was the following: R1 (1/1), R2 (3/-), R3 (1/-), R6 (1/-), L1 (1/-), L2 (7/-), L3 (17/-), L5 (1/-), Lai (24/-), T1 (1/-), C2 (3/-), C3 (2/-), Lawf collaterals (5) and epithelial glia (6/-) (Rivera-Alba et al., 2011).