The effect of adaptation to backgrounds of different light intensities and subsequent recovery in the dark of the oscillatory potentials and a‐ and b‐waves of human ERG was studied. The total energy and dominant frequency of oscillatory potentials were calculated by a combined impulse response and Fourier analysis.When recorded in response to strong flashes of light (colour temperature 6500°K) given at 3 minute intervals in dark adaptation, the oscillatory potentials showed a small amplitude and a high frequency (around 145 Hz). On adaptation to a background of about 10‐2photopic candelas/m2which corresponds to the cone threshold, the amplitude of the oscillatory potentials was enhanced and the dominant frequency changed to 90–100 Hz. At a background of about 1 candela/m2where the sensitivity of the photopic b‐wave becomes higher than that of the scotopic b‐wave, there was a decline in the total energy of the oscillatory potentials. At rod saturation no change in energy nor in frequency of the oscillatory potentials was observed. During adaptation to darkness, the dominant frequency of the oscillatory potentials changed from 90–100 Hz to around 145 Hz as the energy of the oscillatory potentials decreased.When adapted to a background the intensity of which was above the cone threshold, the oscillatory potentials were always present. When the b‐wave was suppressed by a background light the total energy of the oscillatory potentials decreased. The oscillatory potentials are related to photopic retinal function but seem to be influenced also by the scotopi
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