Fig. 4. Response characteristics change with intensity of the stimulus. Here, an ERG trace showing the response to a flash of white light at 5.47x10³ W m^-2 sr^-1 (ND 0.5, black trace) is noticeably biphasic. However, when the same preparation was stimulated by a much lower intensity (1.73x10¹ W m^-2 sr^-1, ND 3.0), the response appears more monophasic and is of smaller magnitude (gray trace). Inset shows onset (1.5 s) and duration (40 ms) of flash.