Chromatic tuning of contour-shape mechanisms revealed through the shape-frequency and shape-amplitude after-effects

Vision Res. 2007 Jun;47(14):1935-49. doi: 10.1016/j.visres.2007.03.010. Epub 2007 May 11.

Abstract

We investigated whether contour-shape processing mechanisms are selective for color direction using the shape-frequency and shape-amplitude after-effects, or SFAE and SAAE [Gheorghiu, E. & Kingdom, F. A. A. (2006). Luminance-contrast properties of contour-shape processing revealed through the shape-frequency after-effect. Vision Research, 46(21), 3603-3615. Gheorghiu, E. & Kingdom, F. A. A. (2007). The spatial feature underlying the shape-frequency and shape-amplitude after-effects. Vision Research, 47(6), 834-844]. All contours were defined along the 'red-green', 'blue-yellow' and 'luminance' axes of cardinal color space. Adapting and test contours were defined along the same or along opposite polarities within a cardinal axis, and along the same or along different cardinal axes. We found (i) little transfer of the after-effects across different within-axis polarities, for all cardinal axes and for both even-symmetric and odd-symmetric contours; (ii) little transfer between the red-green and blue-yellow cardinal axes; (iii) little transfer between the chromatic and luminance cardinal directions for the SAAE; (iv) large transfer between the chromatic and luminance cardinal directions for the SFAE. We conclude that contour-shape mechanisms are selective for within-cardinal axis polarity and for the chromatic axes within the isoluminant plane. However for certain types of contour-shape processing they are poorly selective along the chromatic versus luminance dimension. Overall our results suggest that contour-shape encoding mechanisms are selective for color direction and that color is important for contour-shape processing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Ocular / physiology
  • Color Perception / physiology
  • Contrast Sensitivity / physiology
  • Figural Aftereffect / physiology
  • Humans
  • Light
  • Pattern Recognition, Visual / physiology
  • Photic Stimulation / methods
  • Psychophysics
  • Visual Perception / physiology*