) L4 larvae, SNB-1CFP was detected only in the dorsal cord, confirming that DDs rewired properly, and, as expected, no GABA innervation was observed ventrally (Fig. 3A). UNC-49YFP clusters colocalized with presynaptic varicosities along the dorsal cord (Fig. 3A,B). However, in ventral muscle cells, UNC-49YFP clusters were absent, and only scattered YFP fluorescence was detected in some cells (Fig. 3B)."