The human electroretinogram was elicited by test flashes which followed 2.5 sec after the termination of a colored adaptation. Typically, the electroretinogram consisted of a negative wave followed by a double positive deflection. The negative wave gave evidence of mixed photopic-scotopic activity. The first positive wave showed high red photopic sensitivity when elicited by long wavelength test flashes and scotopic sensitivity when elicited by short wavelength test flashes. The second positive wave was scotopic. When mixed photopic-scotopic activity was present, the negative wave showed a higher proportion of photopic activity than did the positive wave. Blue adaptation favored photopic response while red adaptation permitted an increase in scotopic sensitivity.
JOHN C. ARMINGTON, "Chromatic and Short Term Dark Adaptation of the Human Electroretinogram," J. Opt. Soc. Am. 49, 1169-1175 (1959)