Mixed cultures of neurons, astrocytes, and oligodendrocytes can be produced by plating dissociated 4−/4+ stage EBs in SATO-defined medium (34, 35) supplemented with 5% FCS and 5% equine serum. Examples of neurons (anti-β-tubulin III; A), type-I astrocytes (anti-GFAP; B), type-II astrocytes (anti-GFAP; C), and mature oligodendrocytes (anti-O1; D) are seen in mixed cultures (DIV 9). Scale bars = 20 μm.