1. We measured spatial and temporal contrast thresholds for 70 Xand 40 Y-cells in the lateral geniculate nucleus of cats raised with monocular eyelid closure. Of these cells, 52 X-cells and 30 Y-cells were located in the deprived laminae (i.e., the laminae of the lateral geniculate receiving input from the previously lid-sutured eye). The stimulus display employed to measure contrast thresholds...

Contrast sensitivities were determined for sinusoidal gratings of varying spatial frequencies with and without the presence of a random noise pattern superimposed on the gratings. Control subjects with normal binocular vision and observers with amblyopia were tested to determine the relative effects of noise on contrast sensitivity. For both amblyopes and normal subjects, contrast sensitivities...

A recent series of experiments demonstrated a surprising deterioration of visual motion discrimination with increasing stimulus size for stimuli of high contrast. This counterintuitive finding was explained as a result of surround suppression in visual area V5. Equally paradoxical was the finding that older observers showed better performance than younger observers. This second result was expla...