A non-canonical pathway for mammalian blue-green color vision

The dynamic range of visual coding is extended by having separate ganglion cell types that respond to light increments and decrements. While the primordial color vision system in mammals contains a well-characterized S-On center ganglion cell, less is known about S-Off counterparts. We identified a regular mosaic of S-Off ganglion cells in the ground squirrel. Contrary to convention, S-Off center responses come from an S-On bipolar and inverting amacrine cell.