The axon is the long protuberance from a nerve cell that connects it to the next cell in the circuit.

ECONOMIST: Andrew Huxley

In MS the damage to myelin exposes channels on the surface of the axon, allowing potassium ions to leak out and thus dissipate the electrical current that carries nerve signals.

FORBES: Two Steps Forward

Their main finding was that a nerve impulse, now known as an action potential, is caused by the movement in opposite directions across the axon's surface membrane of sodium and potassium ions.

ECONOMIST: Andrew Huxley