ON THE SPLITTING OF OFF-RESPONSE IN ELECTRORETINOGRAM

Abstract

We often observed the splitting of off-effect (d-wave) in electroretinogram from frogs, toads and chicks. These appeared in different ways in different conditions and we succeeded in making their nature clearer.
1) In general it is relatively difficult to catch the multiple off-response. But, if a test light of weak intensity and short duration is used, diphasic d-wave often appears, especially under low temperature.
2) When the condition stated above is adopted, the splitting of d-wave invariably appears temporarily during the course of light-and dark-adaptation. By dark-adaptation d-wave splits into two or three peaks and the later peaks, gradually diminish behind the faster one. Whereas, in the case of light-adaptation, the off-response becomes multiple with the appearance of the second and the third peak from backward, and piles up to make a large high deflection.
3) The relation between the time course of variation in the height of each peak and the intensity of testing light was observed during the dark-adaptation. It was found that the stronger the stimulus, the more rapidly the second peak appeared and increased in size, and the higher it grew, the more rapidly it diminished as the dark-adaptation progressed.
4) By considering the conditions of splitting we devised a method by which the distinctly splitted off-wave can be caught in its well defined shape which usually continues for over one hour.
5) It was demonstrated that the peaks of a splitted dwave are three or more in number. From several facts it was ascertained again that the multiple d-wave is quite different in character from the rhythmical oscillation originating in optic discharge.
6) The meaning of splitting of d-wave was also discussed in relation to the component potential that is considered to originate the d-wave.