Comparison between the distributions of ganglion cells and cones in the central region of <i>Alouatta</i> and <i>Cebus</i> retinas.

<p>Trichromatic <i>Alouatta</i> differs from dichromatic male <i>Cebus</i> essentially by having high cone density in the foveola. The plots show that this occurs at expenses of a decrease in the number of cones in the remaining of the central region of the <i>Alouatta</i> retina. Other aspects of the retinal distribution of cones and ganglion cells are essentially similar in the trichromatic <i>Alouatta</i> and dichromatic <i>Cebus</i>. (<b>A</b>) Density of cones <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115291#pone.0115291-Franco1" target="_blank">[33]</a> and ganglion cells (this study) across the horizontal meridian of the <i>Alouatta</i> retina. (<b>B</b>) Density of cones <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115291#pone.0115291-Franco1" target="_blank">[33]</a> and ganglion cells <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115291#pone.0115291-Silveira4" target="_blank">[34]</a> across the horizontal meridian of the <i>Cebus</i> retina. Only data from male dichromats were plotted. (<b>C</b>) Cumulative number of cones in the retinas of <i>Alouatta</i> and <i>Cebus</i>. Data from the original study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115291#pone.0115291-Franco1" target="_blank">[33]</a> were used to estimate the total number of cones in ring of retina centered in the foveola. Then, the cumulative number of cones in circular areas was estimated by adding the number of cones in successive rings. (<b>D</b>) Cumulative number of ganglion cells in the retinas of <i>Alouatta</i> and <i>Cebus</i> obtained from ganglion cell densities estimated in this study and the original study of Silveira and colleagues <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115291#pone.0115291-Silveira4" target="_blank">[34]</a>. The cumulative number of ganglion cells in circular retinal areas was estimated by adding the number of ganglion cells in successive rings centered in the foveola.