Electrotonus and excitation in nerve

Abstract

The peculiar relations between electrotonic and excitatory processes lead to the fundamental problem: is the establishment of catelectrotonus (or the disappearance of anelectrotonus) responsible for the development of the change in nerve which culminates in excitation?. It has been suggested , without direct evidence, that a certain shift of the membrane potential by means of polarization or charge of the axon membrane is the physical condition for the occurrence of the physiological reaction in electrical stimulation (Lapicque 1907; Bernstein 1912; Ebbecke 1927). The core-conductor properties of nerve, however, permit the observation, in the polar region, of a possible parallelism between the magnitude of such potential changes at any moment and the onset of the electrical response (Cremer 1932 a ). The physico-chemical basis of this conception has recently been reviewed (Rosenberg 1937). An extended core-conductor scheme is shown in fig. 1, including the longitudinal resistances of both core r 4 and envelope r 3 , and the transverse resistance r 2 (myelin sheath (?), i.e. a substrate of longitudinal resistance much greater than r 3 ) situated in front of the polarizable interface (or static membrane capacity) which is represented by condenser c with leak resistance r 1 .