Fig. 4. Subtype-specific projections of dendrite terminals. (A) Serial confocal images from vitreal (left) to scleral (right) side of the outer nuclear layer. PNAL and N-cadherin expression are shown in magenta and green, respectively. The PNAL-expressing cells at the pedicle levels can be traced back to the double-cones at the level of the outer nuclear layer (asterisks). The principal- and accessory-cone pedicles are indicated by arrowheads and arrows, respectively. (B,E,H) Projection images (upper panels) and optical vertical sections (lower panels) of three types of horizontal cells double-stained with PNA and EGFP. (C,D,F,G,I,J) Higher magnification view of single optical sections taken at the level of double-cone pedicle, double-stained for EGFP and PNAL (C,F,I) or GluR4 (D,G,J). Note that the dendrite terminals of Type I horizontal cells project to both the principal- and accessory-cone pedicles (arrowheads and arrows in C and I, respectively), whereas type III horizontal cells project solely to the accessory-cone pedicles (arrows in I). (K) Schematic drawing of the projection patterns of type I and type III horizontal cell dendrites. Scale bars: 5 µm in A,C,D,F,G,I,J; 10 µm in B,E,H.