Fig. 20. The rod pathway of the mammalian retina. Rod bipolar cells (RB) contact multiple rod photoreceptors (R) in the outer retina. Their axon terminals end in the ON zone of the inner plexiform layer in close proximity to diffuse ganglion cells (DG) but without making a direct contact. Instead, the rod bipolar cells contact two types of amacrine cell, the AII and the A17. (Drawing courtesy of Dr. Helga Kolb)