The Action Potential

Abstract

Bernstein (1902, 1912), the founder of the modern membrane theory, regarded the action potential as the “negative wave” of the resting potential. He considered that during stimulation of a nerve or muscle fiber certain chemical changes which give rise to a reversible increase in the ionic permeability of the cell membrane take place at the point of application of the stimulus. The membrane loses its selective permeability of K⁺ ions, as the result of which the potential difference which exists at rest is quickly equalized, and the resting potential falls to zero. Subsequent restoration of the original ionic permeability leads to a return of the membrane potential to the level of the resting potential.