Swelling of nerve fibers associated with action potentials.

Swelling of nerve fibers during the action potential was demonstrated by three different methods. Generation of a propagated nerve impulse in a crab nerve produced an outward movement of 50 to 100 angstroms of the nerve surfce and a rise in swelling pressure on the order of 5 dynes per square centimeter. In squid giant axons, the amplitude of the observed outward movement of the surface was small.