Membrane potentials were maintained around −60 mV, and a series of step currents with incremental amplitude (10–12 steps, with 10 pA increment) were injected to elicit action potentials, except for spontaneous action potential recordings where resting membrane potential was not adjusted. Na+/K+ currents were recorded in voltage-clamp mode at a holding potential of −70 mV with step-voltage changes as indicated. Evoked synaptic currents were elicited essentially as previously described41 using an extracellular concentric bipolar stimulating electrode (FHC) connected to an Isolated Pulse Stimulator 2100 (A-M Systems). Pharmacological reagents used were Picrotoxin (50 μM, Tocris, GABAAR blocker) and CNQX (50 μM, Tocris, AMPAR blocker). All recordings were performed at room temperature.
