A supernormal period in central axons following single cell stimulation.

Intracellular recordings were obtained from caudate (Cd) nucleus efferent neurons in the cat. A supernormal period, as characterized by increased excitability and conduction velocity, was found for the Cd efferent fibers following either a conditioning antidromic action potential, or a single orthodromic action potential induced by direct current application through the recording microelectrode. These data indicate that the impulse activity of a single fiber can modulate excitability and conduction velocity independent of surround impulse activity.