Small voltage changes at nerve terminals travel up axons to affect action potential initiation

Nerve terminals are generally considered to be the destination points for electrical signals, which propagate unidirectionally from the soma to nerve terminals. We found that small hyperpolarizations or depolarizations (similar to 10 mV) generated under physiological conditions in rat nerve terminals backpropagated up the axon (similar to 400-800 mu m) and changed the threshold for initiating action potentials and thus firing patterns. These results suggest a mechanism for information processing in neurons and neuronal circuits.