Figure 11. Schematic figure illustrating how the two interneuronal populations target different regions of excitability in pyramidal neurons.

Feedforward inhibition is provided by both PV and SST interneurons, but possessing different kinetics and targeted to different parts of the dendritic tree. The progressively depressing PV output targets the proximal dendrites, somata of pyramidal cells and axon initial segment of pyramidal cells, where there is a high density of Hodgkin–Huxley Na⁺ channels. In contrast, the peripheral dendrites, targeted by the SST interneurons, can sustain plateau potentials mediated by NMDA receptors and voltage‐gated Ca²⁺ channels. Dendritic potentials are a powerful drive for bursting behaviour in pyramidal cells. A vetoing inhibition of the pyramidal cells may require the coordinated inhibitory targeting of both these territories.