Spatiotemporal properties of grating motion detection in the center and the periphery of the visual field.

Abstract

Sensitivity to motion was studied by using sinusoidal gratings of contrast 0.4 that were displaced sinusoidally over time. At low motion temporal frequencies, thresholds were proportional to velocity and were independent of spatial frequency. Sensitivity, defined as the reciprocal of the threshold displacement amplitude, declined exponentially with temporal frequencies above the peak. Peak motion sensitivities decreased with visual field eccentricity but could be equalized by applying a spatial scaling function. However, this left a small relative superiority in the periphery for high temporal frequencies of motion, and possible explanations for this residual temporal inhomogeneity are considered.