has characteristic has soma location fasciculates with larval longitudinal connective larval abdominal anterior commissure SP1 neuron FBbt:00001367 Bilaterally paired neuron of the embryo/larva. Each (?) abdominal segment contains a pair of SP1 neurons with an axon that crosses the ventral midline as part of the anterior commissure, wraps around the cell body of its contralateral partner and then extends anteriorly as part of the longitudinal connective. During development, these axons pioneer the anterior commissure and longitudinal connectives. fly_anatomy.ontology VFB:FBbt_00001367 ventral nerve cord pioneer neuron larval CNS neuron bilateral