Oscillatory potentials in the electroretinogram

This paper presents an analog circuit model of the electroretinogram b-wave and subsequent oscillations postulated to result from the depolarization of the retinal glial cells produced by potassium. The system is described by a second-order equation which oscillates under conditions of light adaptation. With dark adaptation the oscillations undergo attenuation. Light falling on the retina ultimately liberates potassium ions and this ionic current is considered to be the system input. A first approximation is an exponentially decaying current which varies depending upon light background, flash intensity and various drug manipulations. This model is a reasonable fit to the electroretinogram over considerable light background levels and is suggested as a useful tool in the study of various pharmacological effects on retinal electrophysiology.