Abstract: Gratings, the luminance profiles of which varied sinusoidally, wereflashed and displayed on a monitor. An electrode recording thetransient visual-evoked potential was placed 5 cm above inion. Fourhealthy subjects wete tested on four levels of contrast of gratings atten spatial frequencies and VEP was recorded by NICOLET CA-1000system. The result shows that amplitude of (C_1-C_2)differs with differentspatial frequencies, and becomes larger as contrast increases. The maximum amplitude of VEP is at approximately 3-5 c/deg,which tallies with the results of Modulation Transfer Function (MTF)obtained in psychophysical experiment. It is found that the amplitude of(C_1-C_2)is sensitive to contrast change. From VEP, one can see that in human visual system, sensitivitydiffers with different spatial frequencies, which is similar to the resultsof MTF.

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