Abstract

It is well known that nerve fibers from the optic tract (as well as from several other pathways) project to the pretectum and drive the pupillomotor nuclei. But it has been less clear as to how or to what extent the pupillary light responses can provide information about visual function. A study by Leventhal, Rodieck, and Dreher (1981), however, may furnish an important clue. The investigators reported that the fibers forming the retinopretectal pathway in primates come from morphological A-, C-, and E- types of retinal ganglion cells. B-cells, the type which projects to the parvocellular layers of the lateral geniculate nucleus (LGN), do not terminate in the pretectum. A-cells, the type which also projects to the magnocellular layers of the LGN, do. (Hereafter, we use the terms M- and P-pathway in accordance with Shapley (1990) when speaking of the A- and B-cells, respectively, or die neural signals that originate from the two).

© 1991 Optical Society of America