June 2006
Volume 6, Issue 6
Free
Vision Sciences Society Annual Meeting Abstract  |   June 2006
Human cortical responses to illusory and actual luminance variations
Author Affiliations
  • Huseyin Boyaci
    Department of Psychology, University of Minnesota
  • Fang Fang
    Department of Psychology, University of Minnesota
  • Scott O. Murray
    Department of Psychology, University of Washington
  • Daniel J. Kersten
    Department of Psychology, University of Minnesota
Journal of Vision June 2006, Vol.6, 706. doi:10.1167/6.6.706
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Huseyin Boyaci, Fang Fang, Scott O. Murray, Daniel J. Kersten; Human cortical responses to illusory and actual luminance variations. Journal of Vision 2006;6(6):706. doi: 10.1167/6.6.706.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

We studied the cortical responses to illusory luminance variations induced by the Cornsweet effect, as well as actual luminance variations. Both the illusory and actual luminance variations were composed of two flanking territories and a contrast border between them. In the Cornsweet effect, two equiluminant flanking territories appear to have different luminances due to a region composed of two opposite sign luminance gradients and a contrast border between them. In the “actual” condition the luminance on both sides of the border were uniform and counter-phase modulated in time around the mean luminance (square-wave modulation, 0.5Hz). In the “illusory” condition, the luminance of the flanking territories remained constant while the gradients within the Cornsweet region reversed their signs in time (square-wave modulation, 0.5Hz.) This modulation induced the illusory percept of an animated luminance change across the flanking territories, which were the regions of interest. We measured reliable BOLD modulation in early visual cortical regions of interest, particularly in V2 and V3, in response to both illusory and actual luminance variations. The magnitude of the BOLD response to the illusory luminance variation was similar to the response to the actual luminance variation in those areas. Our results suggest that neurons in early visual cortex are sensitive to illusory luminance changes engendered by distant scene cues.

We also addressed the role of perceived 3D configuration on the fMRI signal, where the Cornsweet-like luminance pattern is induced either by surface pigmentation, or by surface curvature and spatial layout of light sources (Knill and Kersten, 1991).

Boyaci, H. Fang, F. Murray, S. O. Kersten, D. J. (2006). Human cortical responses to illusory and actual luminance variations [Abstract]. Journal of Vision, 6(6):706, 706a, http://journalofvision.org/6/6/706/, doi:10.1167/6.6.706. [CrossRef]
Footnotes
 This work was supported by NIH grant EY015261 (HB and DJK), Doctoral Dissertation Fellowship from the University of Minnesota (FF). The 3T scanner at the University of Minnesota, Center for Magnetic Resonance Research is supported by BTRR P41 008079 and by the MIND Institute. and BTRR P41 008079 and the MIND Institute.
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×