Stepwise, non-adherent differentiation of human pluripotent stem cells to generate basal forebrain cholinergic neurons via hedgehog signaling por Crompton, L, Byrne, M, Taylor, H, Kerrigan, T, Bru-Mercier, G, Badger, J, Barbuti, P, Jo, J, Tyler, S, Allen, S, Kunath, T, Cho, K, Caldwell, M