How can a minority of GABA interneurons hold back a majority of excitatory cells? · Grey Matter

Each interneuron contacts many pyramidal cells, fires fast without tiring, and often synapses on the cell body or the start of the axon, where it has the most control over whether a spike is produced.

How can a minority of GABA interneurons hold back a majority of excitatory cells?

Each interneuron contacts many pyramidal cells, fires fast without tiring, and often synapses on the cell body or the start of the axon, where it has the most control over whether a spike is produced. Interneurons are driven by the same inputs as their targets, so inhibition arrives a millisecond or two after excitation and scales with it, which keeps the ratio of the two roughly constant. GABA-A inhibition also works by shunting: open chloride channels cancel excitatory currents even when the voltage barely moves. Interneurons make up roughly a fifth to a quarter of neocortical neurons in rodents and a larger share in humans.