Cortical summation and attentional modulation of combined chromatic and luminance signals

Jasna Martinovic* (Corresponding Author), Soren K. Andersen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)
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Cortical networks that process colour and luminance signals are often studied separately, although colour appearance depends on both colour and luminance. In fact, objects in everyday life are very rarely defined by only colour or only luminance, necessitating an investigation into combined processing of these signals. We used steady-state visual evoked potentials (SSVEPs) to investigate (1) cortical summation of luminance and chromatic contrast and (2) attentional modulation of neural activity driven by competing stimuli that differ in chromoluminant content. Our stimuli combined fixed amounts of chromatic contrast from either of the two cone-opponent mechanisms (bluish and yellowish; reddish and greenish) with two different levels of positive luminance contrast. Our experiments found evidence of non-linear processing of combined colour and luminance signals, which most likely originates in V1-V3 neurons tuned to both colour and luminance. Differences between luminance contrast of stimuli were found to be a key determinant for the size of feature-based voluntary attentional effects in SSVEPs, with colours of lower contrast than the colour they were presented with receiving the highest level of attentional modulation. Our results indicate that colour and luminance contrast are processed interdependently, both in terms of perception and in terms of attentional selection, with a potential candidate mediating their link being stimulus appearance, which depends on both chromaticity and luminance.
Original languageEnglish
Pages (from-to)390-403
Number of pages14
Early online date4 May 2018
Publication statusPublished - 1 Aug 2018

Bibliographical note

The work was supported by BBSRC new investigator grant BB/H019731/1 to JM. We would like to thank Justyna Mordal and Zarko Milojevic for their help with data collection.


  • colour
  • luminance
  • attention
  • contrast
  • bottom-up
  • top-down
  • SSVEPs
  • cone-opponent mechanisms


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