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

Sophie M. Wuerger, Alexa Ruppertsberg, Stephanie Malek, Marco Bertamini, Jasna Martinovic

Research output: Contribution to journalArticle

5 Citations (Scopus)
5 Downloads (Pure)

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.
Original languageEnglish
Pages (from-to)239-246
Number of pages8
JournalVisual Neuroscience
Volume28
Issue number3
DOIs
Publication statusPublished - May 2011

Fingerprint

Color
Myeloma Proteins

Keywords

  • Motion Integration
  • colour
  • global motion
  • ON/OFF channels
  • Quick model
  • perception
  • discrimination
  • color
  • segmentation
  • mechanisms
  • luminance
  • noise

Cite this

The integration of local chromatic motion signals is sensitive to contrast polarity. / Wuerger, Sophie M.; Ruppertsberg, Alexa; Malek, Stephanie; Bertamini, Marco; Martinovic, Jasna.

In: Visual Neuroscience, Vol. 28, No. 3, 05.2011, p. 239-246.

Research output: Contribution to journalArticle

Wuerger, Sophie M. ; Ruppertsberg, Alexa ; Malek, Stephanie ; Bertamini, Marco ; Martinovic, Jasna. / The integration of local chromatic motion signals is sensitive to contrast polarity. In: Visual Neuroscience. 2011 ; Vol. 28, No. 3. pp. 239-246.
@article{9301c7f42b9942e08b51f3358b67eeb3,
title = "The integration of local chromatic motion signals is sensitive to contrast polarity",
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.",
keywords = "Motion Integration, colour, global motion, ON/OFF channels, Quick model, perception, discrimination, color, segmentation, mechanisms, luminance, noise",
author = "Wuerger, {Sophie M.} and Alexa Ruppertsberg and Stephanie Malek and Marco Bertamini and Jasna Martinovic",
year = "2011",
month = "5",
doi = "10.1017/S0952523811000058",
language = "English",
volume = "28",
pages = "239--246",
journal = "Visual Neuroscience",
issn = "0952-5238",
publisher = "Cambridge University Press",
number = "3",

}

TY - JOUR

T1 - The integration of local chromatic motion signals is sensitive to contrast polarity

AU - Wuerger, Sophie M.

AU - Ruppertsberg, Alexa

AU - Malek, Stephanie

AU - Bertamini, Marco

AU - Martinovic, Jasna

PY - 2011/5

Y1 - 2011/5

N2 - 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.

AB - 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.

KW - Motion Integration

KW - colour

KW - global motion

KW - ON/OFF channels

KW - Quick model

KW - perception

KW - discrimination

KW - color

KW - segmentation

KW - mechanisms

KW - luminance

KW - noise

U2 - 10.1017/S0952523811000058

DO - 10.1017/S0952523811000058

M3 - Article

C2 - 21426617

VL - 28

SP - 239

EP - 246

JO - Visual Neuroscience

JF - Visual Neuroscience

SN - 0952-5238

IS - 3

ER -