Noise measurements in axon membranes.

A fluctuation (noise) component, which arises from spontaneous microscopic conductance perturbations, about the mean conduction characteristics of small areas of axon membrane has been measured and appears to relate to voltage-dependent potassium-ion movements. Since the kinetics of relaxing membrane structures which produce ion permeation noise may be deduced from the form of power density spectra of fluctuations, a comparison of measured and theoretical noise spectra may lead to direct tests of conduction of models.