June 2007
Volume 7, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   June 2007
Cross-orientation masking in the red-green isoluminant and luminance systems
Author Affiliations
  • Jose Medina
    McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, H3A 1A1, Canada
  • Tim Meese
    School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, UK
  • Kathy Mullen
    McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, H3A 1A1, Canada
Journal of Vision June 2007, Vol.7, 257. doi:10.1167/7.9.257
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Jose Medina, Tim Meese, Kathy Mullen; Cross-orientation masking in the red-green isoluminant and luminance systems. Journal of Vision 2007;7(9):257. doi: 10.1167/7.9.257.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose: Cross-orientation masking (XOM) is defined psychophysically as the phenomenon whereby detection of a test grating is masked by the presence of a superimposed stimulus at an orthogonal orientation. A previous study found that XOM for achromatic stimuli is strongest at mid-high temporal and low spatial frequencies, the putative M cell range (Meese and Holmes, Proc. R. Soc. B., 274, p127, 2007). Here we investigate whether color vision can support XOM by using red-green isoluminant stimuli, and achromatic stimuli for comparison with the luminance system.

Methods: Horizontal Gabor stimuli (Gaussian contrast envelope, σ=2 degrees) were modulated at two spatial (0.375 & 0.75cpd) and two temporal frequencies (2 & 4Hz). An orthogonal vertical Gabor patch with the same spatio-temporal configuration was superimposed (i.e. a plaid). Binocular contrast detection thresholds were determined using a temporal 2AFC staircase method over a wide range of mask contrasts (scaled in multiples of detection threshold).

Results: We find three new results for color vision: 1. robust XOM for color vision for the spatio-temporal frequencies tested over a wide range of mask contrasts; 2. greater cross-orientation facilitation at low mask contrasts for chromatic than for achromatic stimuli, and 3. significantly greater masking for the chromatic than the achromatic stimuli when mask contrast is high.

Conclusions: Such robust and distinct chromatic masking effects indicate that M cells do not exclusively support cross orientation masking in this spatio-temporal range and suggest differential constraints on chromatic compared to achromatic cross-orientation suppression along the cortical or subcortical streams.

Medina, J. Meese, T. Mullen, K. (2007). Cross-orientation masking in the red-green isoluminant and luminance systems [Abstract]. Journal of Vision, 7(9):257, 257a, http://journalofvision.org/7/9/257/, doi:10.1167/7.9.257. [CrossRef]
Footnotes
 Support: CIHR grant MOP-10819.
×
×

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.

×