2.5 × 105 NPCs were seeded onto poly-ornithine/Laminin-coated acid-etched coverslips (cultured in 24-well plates), which were then used for recordings. Neurons were recorded using conventional patch-clamp electrophysiology techniques in whole-cell configuration. Cells were visualized on an Olympus BX51WI upright microscope using IR-DIC imaging with an Olympus Oly-140 IR camera. Signals were sampled at 20 kHz through a Multi-Clamp 700B amplifier and digitized using a Digidata 1440 digitizer (Molecular Devices, Sunnyvale, CA) and filtered between 1000–10,000 Hz. Neurons were bathed at 32 °C in artificial cerebral spinal fluid (ACSF) containing (in mM): sodium chloride, 119; calcium chloride, 2; potassium chloride, 2.5; magnesium chloride, 1.3; D-glucose, 11; sodium bicarbonate, 26.2; sodium phosphate, 1. All chemicals were purchased from Sigma–Aldrich Co. (St. Louis, MO), unless otherwise stated. Patch pipettes were made from borosilicate capillary tubes (World Precision Instruments, Sarasota, FL) pulled on a vertical gravity puller (Narishage International USA, East Meadow, NY) to a final pipette resistance of 3–5 MΩ. Neurons were patched with pipettes containing an internal solution containing (in mM): potassium-D-gluconate, 140; sodium chloride, 4; magnesium chloride, 2; EGTA, 1.1; HEPES,
