On the activating and depressing effects of light adaptation on the electroretinogram of the frog's eye

Abstract

A study was made of the dynamics of changes in individual waves of the frog rhythmic ERG after switching off prolonged adaptive illumination. With the ratio of intensity of the test and adaptive light approximating 1, in a wide range, irrespective of the absolute values of intensity, colour and total energy of the adaptive light, the waves “a” and “d” proved sharply increased and gradually diminished in the course of dark adaptation. If the test flashes were ten to fifteen times less intensive than the adaptive light, the “a” and “d” waves proved to be reduced and gradually increased in the course of dark adaptation. ERG wave “b” diminished with any ratio of adaptation intensity and test intensity after the prolonged illumination was switched off. So, there is no correlation in the changes of wave “b”, or “a” and “d” ERG waves after light adaptation has been switched off. This is regarded as proof of the existence of two relatively independent types of adaptation processes in the frog's retina.