Abstract
Abstract: :
Purpose: To study the interaction of visual signals from the two eyes with visual evoked cortical potentials (VECPs) elicited by pseudorandom binary sequence (PRBS) stimuli. Methods: A PRBS was used to drive two independent LED arrays to elicit VECPs. The right and left eyes were simultaneously stimulated by two different series of PRBS stimuli. The impulse response function of each eye was calculated from the raw data by cross-correlating the PRBS and the response. The effect of changing the luminosity of the LEDs parametrically on the responses obtained from the two eyes was evaluated. Results: The impulse response, obtained from ten volunteers with normal vision, had similar characteristics as the conventional VECP with a major positive peak at P100. When two eyes were bilaterally exposed to two PRBS stimuli of the same luminosity, the P100 amplitudes of two eyes were decreased by the same amount from that obtained by stimulating only one eye. When the luminosity in the two eyes was different, the VECP amplitude in the eye with the dimmer stimuli decreased, and the amplitude in the contralateral eye increased. Conclusion: Our PRBS-VECP method required a relatively shorter time to record the VECPs from the two eyes than the conventional transient flash/pattern VECP method because our method allowed us record the two monocular VECPs simultaneously. Our results clearly demonstrated that interocular luminance interaction can be detected electrophysiologically in normal subjects by using PRBS- driven stimuli.
Keywords: 394 electrophysiology: non-clinical • 621 visual cortex • 329 binocular vision/stereopsis