[Correspondence of depth sensitivity and visually evoked potential amplitude in retinal eccentricity]

It is believed that an enhancement of visual evoked potential (VEP) amplitude in response to stereograms is due to the activity of disparity-sensitive neurons in the visual center. However, it is unclear whether the enhancement works only on retinal disparity cues or on other depth cues as well, which are derived from the mental process of recognizing a depth. The aim of this study is to analyze this relationship by comparing the degree of amplitude increase in the VEP with that of the magnitude in depth perception by viewing a stereopair with a stereoscope. The reduction of the retinal disparity sensitivity in increasing retinal eccentricity was confirmed by psychophysical measurement tests and visual evoked potential measurement. However, the reduction rate of the sensitivity curve was greater in the VEP than in the psychophysiological curve. This means that changes in the VEP, when responding to a sterogram, are mainly due to factors in the disparity sensitive neurons rather than in the mental process of recognizing a depth.