Figure 10. "Decision Tree" structure of iGluR expression in retinal neurons

Retinal neurons can be classified in a binary "decision tree" based on their glutamate receptor expression pattern. Neurons that express only kainate receptors are classified as rod photoreceptors. NMDAR negative cells may be either amacrine or bipolar cells; bipolar preferentially cells express GluR5, and amacrine cells GluR6. The remaining NMDAR positive cells are either ganglion cells or amacrine cells. Ganglion cells almost always express GluR4 and a combination of GluR5-7. P5 ganglion cells express the flip isoforms of the AMPARs almost as commonly as the flop isoforms.