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The integration of local chromatic motion signals is sensitive to contrast polarity

Published online by Cambridge University Press:  23 March 2011

SOPHIE M. WUERGER*
Affiliation:
School of Psychology, University of Liverpool, Liverpool, UK
ALEXA RUPPERTSBERG
Affiliation:
Department of Optometry, University of Bradford, Bradford, UK
STEPHANIE MALEK
Affiliation:
Department of Psychology, University of Halle-Wittenberg, Halle, Germany
MARCO BERTAMINI
Affiliation:
School of Psychology, University of Liverpool, Liverpool, UK
JASNA MARTINOVIC
Affiliation:
School of Psychology, University of Aberdeen, Aberdeen, UK
*
*Address correspondence and reprint requests to: Sophie M. Wuerger, School of Psychology, University of Liverpool, Eleanore Rathbone Building, Bedford Street South, Liverpool L697ZA, UK. E-mail: s.m.wuerger@liverpool.ac.uk

Abstract

Global motion integration mechanisms can utilize signals defined by purely chromatic information. Is global motion integration sensitive to the polarity of such color signals? To answer this question, we employed isoluminant random dot kinematograms (RDKs) that contain a single chromatic contrast polarity or two different polarities. Single-polarity RDKs consisted of local motion signals with either a positive or a negative S or L–M component, while in the different-polarity RDKs, half the dots had a positive S or L–M component, and the other half had a negative S or L–M component. In all RDKs, the polarity and the motion direction of the local signals were uncorrelated. Observers discriminated between 50% coherent motion and random motion, and contrast thresholds were obtained for 81% correct responses. Contrast thresholds were obtained for three different dot densities (50, 100, and 200 dots). We report two main findings: (1) dependence on dot density is similar for both contrast polarities (+S vs. −S, +LM vs. −LM) but slightly steeper for S in comparison to LM and (2) thresholds for different-polarity RDKs are significantly higher than for single-polarity RDKs, which is inconsistent with a polarity-blind integration mechanism. We conclude that early motion integration mechanisms are sensitive to the polarity of the local motion signals and do not automatically integrate information across different polarities.

Type
Research Articles
Copyright
Copyright © Cambridge University Press 2011

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References

Braddick, O. (1993). Segmentation versus integration in visual motion processing. Trends in Neurosciences 16, 263268.Google Scholar
Brainard, D. (1996). Cone contrast and opponent modulation color spaces. In Human Color Vision, ed. Kaiser, P.K. & Boynton, R.M., pp. 563579. Washington, DC: Optical Society of America.Google Scholar
Croner, L.J. & Albright, T.D. (1997). Image segmentation enhances discrimination of motion in visual noise. Vision Research 37, 14151427.CrossRefGoogle ScholarPubMed
Cropper, S.J. & Wuerger, S.M. (2005). The perception of motion in chromatic stimuli. Behavioural and Cognitive Neuroscience Reviews 4, 192217.CrossRefGoogle ScholarPubMed
Derrington, A.M., Krauskopf, J. & Lennie, P. (1984). Chromatic mechanisms in lateral geniculate nucleus of macaque. The Journal of Physiology 357, 241265.CrossRefGoogle ScholarPubMed
Edwards, M. & Badcock, D.R. (1994). Global motion perception: Interaction of the ON and OFF pathways. Vision Research 34, 24232432.CrossRefGoogle ScholarPubMed
Graham, N. (1989). Visual Pattern Analyzers Vol. 16. Oxford University Press.CrossRefGoogle Scholar
Kaiser, P.K. & Boyton, R.M. (1996). Human Color Vision. Washington, DC: Optical Society of America.Google Scholar
Li, H.-C.O. & Kingdom, F.A.A. (2001). Segregation by colour/luminance does not necessarily facilitate motion discrimination in noise. Perception & Psychophysics 63, 660675.Google Scholar
MacLeod, D.I.A. & Boynton, R.M. (1979). Chromaticity diagram showing cone excitation by stimuli of equal luminance. Journal of the Optical Society of America. A 69, 11831186.Google Scholar
Martinovic, J., Meyer, G., Mueller, M. & Wuerger, S.M. (2009). S cone signals invisible to the motion system can improve motion discrimination via grouping-by-colour. Visual Neuroscience 26, 237248.CrossRefGoogle Scholar
McLellan, J.S. & Eskew, R.T. (2000). ON and OFF S-cone pathways have different long-wave cone inputs. Vision Research 40, 24492465.Google Scholar
Meyer, G., Wuerger, S.M., Roehrbein, F. & Zetzsche, C. (2005). Low-level integration of auditory and visual motion signals requires spatial co-localisation. Experimental Brain Research 166, 538547.Google Scholar
Quick, R.F. (1974). A vector-magnitude model of contrast detection. Kybernetik 16, 6567.CrossRefGoogle ScholarPubMed
Regan, B.C., Reffin, J.P. & Mollon, J.D. (1994). Luminance noise and the rapid determination of discrimination ellipses in colour deficiency. Vision Research 34, 12791299.Google Scholar
Rentzeperis, I. & Kiper, D.C. (2010). Evidence for color and luminance invariance of global form mechanisms. Journal of Vision 10, 114.Google Scholar
Ruppertsberg, A., Wuerger, S.M. & Bertamini, M. (2003). The chromatic input to global motion perception. Visual Neuroscience 20, 421428.CrossRefGoogle ScholarPubMed
Ruppertsberg, A., Wuerger, S.M. & Bertamini, M. (2007). When S-cones contribute to global motion perception. Visual Neuroscience 24, 18.Google Scholar
Sankeralli, M.J. & Mullen, K.T. (2001). Bipolar or rectified chromatic detection mechanisms? Visual Neuroscience 18, 127135.Google Scholar
Snowden, R.J. & Edmunds, R. (1999). Colour and polarity contributions to global motion perception. Vision Research 39, 18131822.CrossRefGoogle ScholarPubMed
To, M.P.S., Lovell, P.G., Troscianko, T. & Tolhurst, D.J. (2010). Perception of suprathreshold naturalistic changes in colored natural images. Journal of Vision 10, 122.CrossRefGoogle ScholarPubMed
van der Smagt, M.J., Breij, E.C.W. & van de Grind, W.A. (2000). Spatial structure, contrast polarity and motion integration. Vision Research 40, 20372045.Google Scholar
Watson, A.B. & Pelli, D. (1983). QUEST: A Bayesian adaptive psychometric method. Perception & Psychophysics 33, 113120.CrossRefGoogle Scholar
Wehrhahn, C. & Rapf, D. (1992). ON- and OFF-pathways form separate neural substrates for motion perception: Psychophysical evidence. The Journal of Neuroscience 12, 22472250.CrossRefGoogle ScholarPubMed
Westheimer, G. (2007). The ON-OFF dichotomy in visual processing: From receptors to perception. Progress in Retinal & Eye Research 26, 636648.Google Scholar
Wilson, J.A., Switkes, E. & De Valois, R.L. (2004). Glass pattern studies of local and global processing of contrast variations. Vision Research 44, 26292641.CrossRefGoogle ScholarPubMed
Wuerger, S.M., Watson, A.B. & Ahumada, A. (2002). Towards a spatio-chromatic standard observer for detection. in Human Vision and Electronic Imaging VII, Proceedings, Vol. 4662, ed. Rogowitz, B.E. & Pappas, T.N., pp. 159172. DOI: 10.1117/12.469512.Google Scholar