Human primary cortical neurons were prepared in our laboratory by Dr. Darbinyan [4 (link),25 (link)–28 (link)]. Human fetal brains resulting from elective abortion were obtained from Advanced Bioscience Resources (ABR), Inc., Alameda, CA 94501 USA, under a protocol approved by Temple University’s IRB. The protocol also complied with NIH guidelines at the time, although currently, NIH guidelines do not permit new collection of human fetal tissues. In brief, 16-weeks fetal brain (approx 13 g) was collected and treated with Tryple Express enzyme (Invitrogen, CA), DNase I (10 U/mL; Sigma, St. Eouis, MO) for 15 min at 7°C, then washed three times with Hibernate E medium. Neurobasal medium containing B27 supplement and 0.25 mM Glutamax was used for a tissue trituration with a glass Pasteur pipette, and cells were then plated on poly-D-lysine-coated 60-mm dishes (Sigma). After 16 hours, 1 μM of Cytosine arabinoside Ara-C (Sigma) was added to cells for 48 hours. Cells were cultured in Neurobasal medium containing several antibiotics, including 10 μg/mL gentamycin, 100 units/mE penicillin and 10 μg/mL streptomycin. Medium also contained one μg of antifungal fungizone (Life Technologies, Inc.). Cells were maintained at 37°C incubator.