Adult neurosphere number, eGFP expression (relative to cell confluence), and number of proliferating NPCs were quantified after GDF3 treatment using an Innovatis Cellavista Imager (Dynamic Devices, Wilmington, DE). To quantify NPC proliferation, 10x images were collected by Cellavista and BrdU+ nuclei were detected and quantified by Cellavista software using the cell nuclei count function.