Efficiency of chemotaxis in cell-ablated animals. Time spent at each position as fraction of total time is indicated by the darkness of that position. A , Untreated wild-type N2. B , Untreated N2 animals on assay plates without NaCl. C , Untreated ttx-3(ot22) mutants. D , N2 animals with ASER neurons ablated. E , N2 animals with both ASER and ASEL neurons ablated. F , Ex[ins-1::Venus] animals with AIA neurons ablated. G , Ex[glr-1::Venus] animals with AIB neurons ablated. H , Ex[ttx-3::GFP] animals with AIY neurons ablated. I , Ex[lin-11::nlsGFP] animals with AIZ neurons ablated. J , N2 animals with ASI neurons ablated. K , Ex[ttx-3::GFP] animals with AIY and ASI neurons ablated. L , Ex[ttx-3::GFP ins-1::Venus] animals with AIY, ASI, and AIA neurons ablated. M , N2 animals with RIA neurons ablated. N , Ex[zig-5::Venus] animals with RIV neurons ablated. O , N2 animals pretreated in NaCl-containing buffer. The numbers of animals tested for each test and average chemotaxis indices are shown for each panel.