of neuroectoderm and immunolabeling for neuronal MAP2 as well as SOX2-positive neural progenitor cells, as previously described [64] (S2 Fig). At 60 days (60d) and 90–100 days (90d) in culture, the organoids demonstrated formation of a rolling morphology structure with rosette-like neuroprogenitor rich regions in which the neuroprogenitor cells are spatially arranged in a spherical format, and unorganized regions that contain dense populations of MAP2-positive neurons (S2B Fig). With age, immunoreactivity for SOX2 appeared to decrease, while MAP2 immunoreactivity remained (S2C and S2D Fig). Since we are interested in age-related neural pathology, we found that the large regions of neuron-rich tissue produced by the modified Kadoshima et al protocol [64] best suited our modeling needs.
