Characteristics of the typical RS neurons in the ACC. A, Schematic representation of the location of the recorded neurons (a and b); B, Biocytin profiles of two representative ACC RS pyramidal neurons as visualized with confocal laser scanning microscopy. Scale bar = 50 μm. C, Superimposed current-clamp traces in response to a series of intracellular current pulses (1000 ms, 80 pA per step). The neurons exhibited an AHP with a slow component. Note that an obvious deflection was observed during the hyperpolarizing phase; D, I-V plots constructed from the values of traces shown in (C) displayed linearity in the membrane voltage range between -65 and -90 mV; E, Traces evoked by the same current injections (400 ms, 100 pA) as the neurons was depolarized from -85 to -50 mV. The more the cells were depolarized, the more the action potentials were elicited by the same depolarizing pulse. Each spike was followed by a sAHP that lasted for tens of milliseconds. Note that the black traces were for cell (a) and gray traces for cell (b); F, Action potential trains were evoked by 400 ms current injection of 160, 180 and 200 pA from the holding potential of -70 mV. Note the increase in the frequency of action potential discharge with increasing current injections. Note that the black traces were fro cell (a) and gray traces for cell (b).