FIGURE 9.

GFP + cells and fibers in the optic tectum of Tg(1.4dlx5a-dlx6a:GFP)^ot1. (A–D’) Labeled tectal cells (confocal images and tracings) in adult (A–B’) and 20dpf (E–E’) transgenic zebrafish Tg(1.4dlx5a-dlx6a:GFP)^ot1. (A-D), Images projection from confocal stacks. (A) Section through the optic tectum of an adult fish showing GFP + pyramidal or type I cells (arrowheads, labeled “I” in the photograph) with their characteristic dendritic arbors (arrows) and cell bodies in the periventricular cell layer that are likely to correspond to type XIV cells from Meek and Schellart (1978) (outlined arrowheads, labeled “XIV” in the photograph). (B,B’) Section showing 4 GFP + pyramidal cells (B) and their tracing (B’). Note the sparse distribution of the cell bodies (arrowheads). Cell marked with an asterisk in (B’) shows quite broad dendritic arbor, overlapping with adjacent ones. Area marked by dotted lines: SM. (C) Dorsal view of a whole mount brain of a 20dpf fish showing labeled structures in the optic tectum. Arrowheads point to the cell bodies of the cells traced in (D’). (D) Detail of the area squared in (C) showing the dendritic arbor (arrowheads) of a pyramidal cell. (D’) Tracing of two adjacent pyramidal cells observed in (D’), showing the area covered by their dendritic arbor (dashed line). Note that the dendritic arbor of the cells covers roughly circular and oval areas, and the slight overlap between them. Axis: D, dorsal; M, medial; R, rostral. For abbreviations, see list. Scale bars: 100 μm (A-C); 50 μm (D,D’).