Fig. 9.

Distribution of pretectal axons with respect to preganglionic motoneurons in the Edinger–Westphal nucleus. a–h Low-magnification illustration shows the sections in a rostral to caudal series, and the high-magnification illustrations show the region of AM and EWpg for each section. The retrogradely labeled motoneurons from a ciliary ganglion injection of WGA–HRP are shown on the right and counterstained somata of the nuclei are shown on the left. An injection of biocytin (red shading) in the pretectum (g, h) that included OPt anterogradely labeled axons (red) in EWpg on both sides. The boxed region shows a higher magnification view of two cells in (e), which displayed numerous close associations (blue arrows) with BDA-labeled pretectal axons. Labeled cells that showed close associations are indicated by blue arrowheads (c–e). NB: the dispersed nature of EWpg in (h) made it difficult to define the nucleus on the counterstained side