Human iPSC-derived BrainSpheres. At 8 weeks of differentiation, mature BrainSpheres contain a diversity of neuronal and glial cell populations as shown by the expression of neuronal and glial markers by immunofluorescence. Glial cell populations include O1+ oligodendrocytes (a, b) that are in close interaction with NF+ axonal processes (c, d) and GFAP+ astrocytes (e, f). Oligodendroglia also exhibited expression of Myelin Basic Protein (MBP) in association with axonal processes (g, h). Neuron populations express specific markers such as TUBB3 and MAP2 (i–l) and seem to be mixed among GFAP+ astroglia (k, l). Scale Bar: 20 μm.