Number of caudal periaqueductal gray (cPAG)-projecting retinal ganglion cells (RGCs) required to tile up the retinal surface.

<p>The calculations are used to determine the number of cPAG-projecting RGCs that are required to cover the whole retinal surface. The size of the retinal surface area is referred from Fite’s study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103306#pone.0103306-Fite1" target="_blank">[11]</a>; tiling up the whole retinal surface is generally considered as a criterion for a type of RGC, and our results indicate approximately 1300 cPAG-projecting RGCs are required to cover the whole retinal surface in this species.