Effect of adaptation and wavelength on the power spectrum of human oscillatory potentials

Oscillatory potentials were recorded from four adult subjects under dark- and light-adapted conditions with photopically balanced red and blue flashes. The responses between 80 and 200 Hz were analyzed by means of a Fast Fourier transform program. The results show a robust change in the power--but not in the frequency composition--with the different stimulus conditions. We suggest that an analysis of the total power within this frequency band may provide a quantitative way of evaluating the duplex nature of the oscillatory potentials.