Spectral analysis of the visually evoked occipitogram in man

Abstract

The visually evoked occipitogram was studied in two color-normal observers over the visible spectrum (380–700 nm) in 16 steps at matched intensities. Confirming earlier reports, the waveform of the responses varies as a function of wavelength. A Fourier analysis indicates that this chromatic coding is confined primarily to the 4–8 c/s components in the waveforms. However, uncoded responses are also reported for other color-normal observers, which introduces a note of caution into our interpretation of these findings. These individual differences persist for on-off, on and off evocation. The VEOG responses in several color-deficient observers are also reported, indicating that an amplitude depression exists in the deuten group.