The depolarization of the cell membrane in scotopic conditions opens voltage-gated calcium channels. In scotopic conditions, it is proportional to "L" (meaning no luminance level adaptation). Natural night vision, or scotopic vision, is the ability to see under low-light conditions. One can also define a similar curve for dim conditions (scotopic vision). Below this level, the rod mechanism comes into play providing scotopic (night) vision. The AII amacrine cell is a mediator of signals from rod cells under scotopic conditions. Scotopic vision occurs at luminance levels of 10 to 10 cd/m. Scotopic vision is the vision of the eye under low-light levels. Scotopic vision is dominated by retina amacrine cells, specifically AII-amacrine cells.