Peripheral hyperacuity: three-dot bisection scales to a single factor from 0 to 10 degrees.
Performance of three-dot bisection was determined as a function of the feature separation at eccentricities of 0-10 deg along the inferior vertical field meridian by using dot stimuli scaled in size to compensate for eccentricity. For these briefly flashed dot stimuli, the entire function of three-dot bisection acuity against dot separation worsens away from the fovea with a single scaling factor that is compatible with the change of the cortical magnification factor in area V1. When the presentation duration of the stimulus was lengthened from 150 msec to 1 sec, the improvement was much greater in the fovea than at 10-deg eccentricity for closely separated stimuli. We attribute this difference to a luminance cue (detection of a brightness change) that is present for a long stimulus duration at small separations in the fovea, but not in the periphery.
D005584:Fovea Centralis / Q000502:physiology; D006801:Humans; D012160:Retina / Q000502:physiology*; D012684:Sensory Thresholds; D013028:Space Perception; D013997:Time Factors; D014792:Visual Acuity; D014796:Visual Perception