Is action potential threshold lowest in the axon?

Action potential threshold is thought to be lowest in the axon, but when measured using conventional techniques, we found that action potential voltage threshold of rat cortical pyramidal neurons was higher in the axon than at other neuronal locations. In contrast, both current threshold and voltage threshold of the isolated somato-dendritic spike were substantially higher at the soma. These data indicate that action potential threshold is indeed lowest in the axon.