Primary hippocampal neurons were prepared from C57BL6/F mice (Koatech, South Korea) on embryonic day 17 as described previously.5 Dissociated neurons were obtained by digesting hippocampi with 0.05% trypsin (Invitrogen, USA) for 10 min at 37°C. Neurons were then dissociated by mechanical trituration through Pasteur pipettes (Hilgenberg, Germany). Neurons were plated at onto 10 mm #0 coverslips (TED PELLA, New Hampshire, USA) precoated for 3 h with poly-D-lysine (Sigma, Missouri, USA) in 0.1 M Borate buffer (pH 8.5). Neurons were cultured at 37°C in Neurobasal medium (Gibco) supplemented with B-27 (Gibco by Life Tech, USA), 0.5 mM Glutamax-I (Gibco by Life Tech, New York, USA), L-glutamic acid (Sigma, USA), and 0.5% FBS. Transient transfections for neurons were performed at 8 to 10 days in vitro (DIV 8-10) using Lipofectamine 2000 (Invitrogen, USA) as per manufacturer’s instruction. Neurons were usually tested at DIV 9-11 (16 to 24 h post-transfection).