LONG WAVELENGTH-MIDDLE WAVELENGTH CONE INTERACTION UNDER NO BACKGROUND IN THE ELECTRORETINOGRAM OF THE CYNOMOLGUS MONKEY

We recorded electroretinograms from anesthetized cynomolgus monkeys fo r 30 monochromatic (400-700 nm) full-field stimuli with five different stimulation levels presented without a background light. Waveforms we re analyzed by means of principal component analysis to investigate th e influence of stimulus intensity on long- and middle-wavelength cone interaction. With increasing levels of stimulus intensity, the middle- wavelength cone system showed a slight peak shift and a noticeable inc rease in response, while the long-wavelength cone system showed an obv ious change in peak wavelength rather than response. In addition, spec tral responses in the long-wavelength cone system increased-over the r ed region, whereas they decreased over the yellow region. On the other hand, responses in the middle wavelength cone system increased over t he yellow region much more than over the green region. These complicat ed changes are thought to indicate the induction of long- and middle-w avelength cone interaction by stimulus light.