After 3 weeks of differentiation, cells were trypsinized, and droplets of 100,000 cells in 5 µl were transferred to PLO/FN-coated coverslips. After attachment of spotted cells to the coverslips, 0.5 ml of differentiation medium (N2 medium [27] supplemented with 10 ng/ml GDNF and 10 ng/ml BDNF) was added per well of a 24-well plate for further differentiation and maturation (Fig. 1d). Schematic diagrams of the differentiation procedures are presented in Fig. 3a (MGE differentiation) and b (CGE differentiation).
