Abstract
Purpose: :
To determine where in the afferent neural chain of the visual system the combination of photoreceptor responses which match psychophysical luminance and psychophysical color functions first occur.
Methods: :
Spectral sensitivity functions were determined for a-wave, b-wave and pattern ERG stimulation and compared with the increment-threshold spectral sensitivity and luminance functions of human and rhesus.
Results: :
The bipolar level spectral sensitivity from b-wave ERG response closely resembles the psychophysical luminance function. The pattern ERG spectral sensitivity closely resembles the psychophysical increment-threshold sensitivity. The two differ with the first appearance of greatly amplified short wave response and red-green inhibition at the ganglion cell level in the pattern ERG. When 10deg. homogenous fields are substituted for 1cpd alternating checks in the pattern ERG determinations, the function regresses to resemble the bipolar cell luminance-like function. These data will be discussed in relation to the Helmholtz-Kohlrausch Effect.
Conclusions: :
Color-opponency and short wave amplification are available in the ganglion cell level response in the retina, as is luminance information in the bipolar level response. Eliciting the one or the other is controlled by spatial stimulus factors.
Keywords: retina • brightness and lightness • color appearance/constancy