The retina is a neural circuit with well defined functional properties. Recent advances in transgenic technology enables the labeling and functional manipulation of neural circuits. We recently embarked on employing this technology to labeled specific cell types of the retina by fishing for retinal cell type specific regulatory elements. This will allow us to manipulate membrane properties of such identified cells and build a physiological framework of defined retinal functions. Mutations have also helped us to establish unexpected links between general metabolism and cell type specific functions.