Psychophysical and Electrophysiological Determinants of Motion Detection

Abstract

Displacement thresholds for moving line targets were measured for man and for retinal ganglion cells of cat and monkey. Several studies are summarized and should be of interest for perimetry. A luminous line was stationary at one site and moved at constant velocity to a test site where it again remained stationary. The optimal stimulus parameters for kinetic perimetry were considered to be the range of target luminance, line length and duration of motion which produced minimum and consistent thresholds. For durations of motion below 0.5 seconds, displacement thresholds remained constant for both foveal and peripheral (18 °) vision. Increases in stimulus luminance and line length produced a successive reduction in displacement thresholds in peripheral vision, whereas foveal displacement thresholds were essentially unaffected by these variables. Displacement thresholds were as small or smaller than acuity measures throughout the central 40° of visual field.