Fig. 7. Dendrites of adjacent class II (A), III (B,C) and IV (D,E) neurons do not overlap. (A,A') Dual labeling of the class II neurons vdaA and vdaC. White arrows indicate labeling of motoneurons, and a white arrowhead indicates the axons of vdaA and vdaC. (B,C) Lack of overlap between dendrites of class III neurons (n=6). Examples of dendritic exclusion between dorsal cluster neurons (ddaA and ddaF; B) and ventral neurons (v’pda and vdaD; C) are shown. The confocal images (B,C) are color coded (B',C') to identify the individual branches of each neuron. A white arrow in B' shows an example of avoidance between dendrites of the same neuron (isoneuronal avoidance). Black arrows in B' and C' show cases in which a dendrite from one cell terminates its growth before crossing the dendrite of an adjacent cell. A black arrowhead in B' shows a dendrite that turns away from the dendrites of an adjacent cell. (D,E) Class IV dendrites from adjacent neurons form non-overlapping boundaries (n=21). Examples of dendritic exclusion between v’ada and vdaB (D; dendrites are colored in D') and ddaC and v’ada segmental homologs (E; dendrites are colored in E’) are shown. A white arrow in D shows the axon of v’ada extending to the CNS. White arrowheads in D and E show points of apparent dendritic contact and/or crossing. In these cases, the cell of origin of each dendrite branch was difficult to determine unambiguously. A black arrow in E' shows the location of the segment border. Dorsal is up and anterior is to the left in all panels. Scale bars, 50 µm.