Guidance of neuronal growth cones in the grasshopper embryo. II. Recognition of a specific axonal pathway by the aCC neuron.
In the previous paper, we experimentally analyzed the selective affinity of the pCC growth cone for the MP1/dMP2 fascicle in the grasshopper embryo. Here we describe a similar experimental analysis demonstrating the selective affinity of the aCC growth cone for the U fascicle. These results support the labeled-pathways hypothesis. The 2 sets of cell ablation experiments argue against the simple location of axons, the simple timing of axon outgrowth, and/or simple quantitative differences in the expression of a common surface label being the major determinant in pathway selection by neuronal growth cones. Rather, these 2 examples of growth-cone specificity, together with previous studies on the G growth cone, suggest that neuronal recognition molecules are differentially expressed on the surfaces of different embryonic axonal pathways and tracts and are used to guide growth cones through a series of choice points to their targets.
D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure*; D002450:Cell Communication; D002490:Central Nervous System / Q000196:embryology; D006110:Grasshoppers / Q000196:embryology* / Q000648:ultrastructure; D006651:Histocytochemistry; D007159:Immunologic Tests; D008854:Microscopy, Electron; D009434:Neural Pathways / Q000196:embryology; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure*