Figure 11. Depolarization enhances bursting.

A, triple dendritic patch recording of a dendritic Na⁺-Ca²⁺ AP initiated by injection of an EPSP-shaped waveform (1.6 nA, shown below E) at a distal dendritic location (P1, 650 μm from soma; dashed line) that led to a Na⁺-Ca²⁺ AP and a single back-propagating AP, recorded at a more proximal location (P2, 310 μm; black line) and the soma (P3; blue line). B, EPSP waveform current injection at a distal dendritic location. C, addition of an extra 5 mm KCl to the extracellular solution (total of 7.5 mm KCl) caused progressive depolarization of the resting membrane potential. At 6 mV more depolarized than the control, the same current injection at the distal dendritic location now caused 2 APs. D, at 12 mV more depolarized than the control, the same current injection caused a burst of 3 APs. E, current injection at all three pipettes causing 10 mV depolarization had a similar effect.