glial cells were cultured from the forebrain of newborn wildtype CD1 mice (Franke et al., 1998). Briefly, newborn mouse forebrain homogenates were digested with papain and EDTA for 30 min, cells were dissociated by harsh trituration to avoid growing of neurons, and plated onto T75 flasks in DMEM supplemented with 10% FBS. Upon reaching confluence, glial cells were trypsinized and replated at lower density a total of three times to remove potential trace amounts of mouse neurons before the glia cell cultures were used for co-culture experiment with iN cells. Mouse cortical neurons were cultured as described (Pang et al., 2011), added to iN cells 4–5 days after infection, and co-cultured for an additional 2 weeks.
