Purchase this article with an account.
Remy Allard, Jocelyn Faubert; No dedicated color motion system. Journal of Vision 2014;14(10):19. doi: https://doi.org/10.1167/14.10.19.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The existence of a color motion system distinct from both the luminance and feature tracking motion systems remains controversial. In the current study, we used a mask known to affect luminance-defined motion processing but which should not affect distinct color-defined motion processing: a static, luminance-defined pedestal at high contrast. To neutralize feature tracking, the motion (3.75 Hz) was presented in the near periphery (2 to 3 degrees of eccentricity) at a spatial frequency (~1 cpd) beyond the attentional resolution acuity. The results showed that, in a direction discrimination task, the luminance-defined pedestal affected luminance- and color-defined contrast thresholds by similar proportions (~10x at the highest pedestal contrast) and that this masking was orientation specific as a similar mask orthogonal to the signal modulation had little impact on luminance- and color-defined contrast thresholds. Given that L- and M-cone pathways merge at a processing level that is not orientation specific (i.e., ganglion cells, which have center-surround receptive fields), the masking of a luminance pedestal must interfere with higher processing stages within the luminance pathway where cells are orientation selective (e.g., simple cells). Furthermore, a static luminance-defined mask should not generate any substantial response from cells sensitive to luminance-defined motion (e.g., complex cells), so even if distinct luminance and color motion pathways merged after independent motion extractions, a static, luminance-defined mask should not impair color-defined motion processing. The similar vulnerabilities of luminance- and color-defined motion processing to a static, luminance-defined mask suggest that, when the feature tracking is neutralized, luminance- and color-defined motions are processed by the same motion system. We conclude that there is no dedicated color motion system.
Meeting abstract presented at VSS 2014
This PDF is available to Subscribers Only