Retinal whole-mount from a Brown Norway rat labelled with antibodies against RNA-binding protein with multiple splicing (RBPMS, red; #ABN1376, Millipore, Darmstadt, Germany; 1:250) to identify retinal ganglion cells; and the calcium-binding proteins parvalbumin (PV, green; #P3088, Sigma-Aldrich, St. Louis, MO, USA; 1:200) and calbindin (CB, blue; #300, Swant Inc., Marly, Switzerland; 1:200). Individual color channels are shown as indicated. White arrows indicate retinal ganglion cells expressing both parvalbumin and calbindin. Scale bar = 100 µm. All experiments involving animal use were performed in compliance with the relevant laws and institutional guidelines of Baden-Württemberg, Germany. Previously unpublished data (R.F.).