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This experiment was undertaken to investigate the effects of different types and velocities of apparent motion on the Visual Evoked Potential (VEP). Central (Cz) recording site VEPs were obtained from four males and three females under seven conditions. Significant differences in terms of amplitude and latencies were found between continuous and discrete apparent motion at the Oz derivation only. Theoretical and cell system models describing separate cortical channels for processing continuous and discrete apparent motion were presented to account for the observed differences. The stationary condition produced a significantly shorter latency than all other conditions at Cz. In addition, discernable trends observed between central and occipital recording sites suggest the role of the occipital cortex as the primary processor of motion and for detecting differences in motion velocity.

Visual evoked cortical potentials (VEPs) were recorded from an individual with a mature cataract in one eye. Stimulation was both monocular and binocular and VEPs were obtained from three occipital scalp sites. Comparisons of recordings taken prior to cataract removal and after removal showed a dramatic increase in amplitude of potentials derived through stimulation of the affected eye. Slight differences in hemispheric amplitude prior to surgery suggest a greater degree of opacity in one portion of the affected lens.

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