Receptive field of the bipolar cells

Figure 5.
(Illustration taken from Freberg, 2006. Discovering Biological Psychology.)


The amacrine and horizontal cells sends signals horizontally across the receptive fields and convergence takes place in the retina. As there are approximately 120 million rods and 6 million cones in the retina, more rods have to come together to deliver their signals to one ganglion cell as opposed to one single cone having access to one ganglion cell.
This process of pulling together allows the rods to be more sensitive to changes in the visual field whilst the cones “zooms” into focus.