has soma location fasciculates with supraesophageal ganglion neuron Bolwig nerve optic lobe pioneer neuron OLP fly_anatomy.ontology Tix et al. (1989) state that in 57 out of 62 third instar larval brain samples only three optic pioneer neurons were observed. However, they found three brains showing four of these neurons, and two cases displaying only two. Larderet et al., 2017 also found variability - three in the left hemisphere, four in the right hemisphere. Neuron located in the distal region of the optic lobe (Tix et al., 1989), which persists through development and pioneers Bolwig's nerve. In the developing optic lobe, at larval stage, this group of three neurons are fully differentiated before there is any detectable fiber growth in the rest of the optic lobe. Following this, other neuron projections from the optic lobe follow the same path as these pioneers and fasciculate to form Bolwig's nerve (Tix et al., 1989). They have their cell bodies located together on the ventrolateral side of the larval optic neuropil (Larderet et al., 2017). VFB:FBbt_00003703 FBbt:00003703 pioneer neuron larval efferent neuron cell body rind of larval brain