Clark_2005_Nat.Neurosci_8_137

Knowledge of the site of action potential initiation is essential for understanding how synaptic input is converted into neuronal output. Previous studies have shown that the lowest-threshold site for initiation of action potentials is in the axon. Here we use recordings from visualized rat cerebellar Purkinje cell axons to localize the site of initiation to a well-defined anatomical structure: the first node of Ranvier, which normally forms at the first axonal branch point.