Technical advances such as the uDISCO tissue clearing method [137, 138] in combination with the new generation of OT promoter-driven, BBB-penetrating AAVs expressing GFP [139, 140] would be a suitable tool to map and study the entirety of OTergic projections in murine models of PWS and SYS. The gene discussed is OXT; the disease is Prader-Willi syndrome.