Fig. 3.

The pattern of spontaneous discharge is an intrinsic property of a GG neuron. In intracellular current-clamp recordings, 10-s serial hyperpolarizing and depolarizing currents (10 pA per step) were injected from the resting membrane potential (defined as 0 pA, approximately −55 mV). The effects of current injections were observed on RSS firing (A), phasic firing (B), and sporadic firing (C). Numbers at right in C indicate the total number of spikes evoked from the steady-state membrane potential. Note anode-break excitation. The stimulus waveform is shown in C (bottom). The relationship of depolarizing current injection to firing rate is shown for evoked firing (D) and spontaneous firing (E) from the new membrane potential baseline. The dotted line in E is a linear fit to the data.