Figure 1. Low-threshold bursting in an se-experienced CA1 pyramidal cell.

The experiment was performed 7 days after pilocarpine-se. In this and in subsequent figures, the bottom trace in each panel depicts the stimulus waveform, whereas the top trace shows the voltage response. The resting potential of the neuron is indicated to the left of the uppermost voltage trace. Brief stimuli evoked bursts of 4–5 spikes (A–C; these traces are expanded and overlaid in D to facilitate comparison). Note jitter in spike timing, particularly of later spikes. Spike failure during a burst sometimes revealed a small subthreshold ‘hump’ (see arrows in B, C and E). Adding 100 μm Ni²⁺ to the ACSF caused progressive suppression of bursting (E–G).