Pathways mediating resolution in the primate retina.

In recent years there has been a dramatic increase in knowledge of the anatomy of the primate retina that relates to the pathways involved in visual resolution. The density of cones at the fovea has been shown to have a surprising degree of individual variability and the cone distribution is asymmetric about the fovea with a greater density of cones in nasal than temporal retina. Information about the fine detail of our visual world is carried to the dorsal lateral geniculate nucleus of the thalamus in two parallel pathways. These pathways originate from two morphologically distinct types of ganglion cell; the M-ganglion cells project to the magnocellular layers, P-ganglion cells to the parvocellular layers. Different roles for the two types of ganglion cell in mediating spatial visual resolution have been proposed. These cannot be determined using available physiological and anatomical data.