Fig. 13. ON and OFF layering of the inner plexiform layer in all retinas. The axons of flat midget bipolar cells (FMB) terminate in the distal portion of the inner plexiform layer, which is the OFF zone, whereas those of invaginating midget bipolar cells (IMB) terminate in the proximal portion of the inner plexiform layer, the ON zone. Rod bipolar cell axons (RB) and those of invaginating diffuse bipolars end in the ON zone; those of flat diffuse bipolars (FDB) end in the OFF zone. Other cell labels as in Figure 12. (Drawing courtesy of Dr. Helga Kolb)