sentences:  Primarily, Robo 1 is crucial towards pioneer longitudinal axon guidance in the ventral tract, while Robo 2 is important in the dorsal tract.The signaling associated with the receptor Notch, as well as non-canonical Notch/Abl signaling, have been shown to play a role in the development of longitudinal pioneer neurons in the "Drosophila" ventral nerve cord.The Notch receptor has been shown to interact with interface glia to form a path that longitudinal pioneer neurons can follow.