Brightness–color interactions in human early visual cortex

Dajun Dajun, Ahmed Ouni, Stephanie Chen, Hinde Sahmoud, James Gordon, Robert Shapley

Research output: Contribution to journalArticlepeer-review


The interaction between brightness and color causes there to be different color appearance when one and the same object is viewed against surroundings of different brightness. Brightness contrast causes color to be desaturated, as has been found in perceptual experiments on color induction and color-gamut expansion in human vision. However, it is not clear yet where in the cerebral cortex the brightness– color interaction that causes these major perceptual effects is located. One hypothesis is that brightness and color signals are processed separately and in parallel within the primary visual cortex V1 and only interact in extrastriate cortex. Another hypothesis is that color and brightness contrast interact strongly already within V1. We localized the brightness– color interaction in human V1 by means of recording the chromatic visual-evoked potential. The chromatic visual-evoked potential measurements decisively support the idea that brightness– color interaction arises in a recurrent inhibitory network in V1. Furthermore, our results show that the inhibitory signal for brightness– color interaction is generated by local brightness contrast at the boundary between target and surround, instead of by the luminance difference between the interior of the color target and its large background.

Original languageEnglish (US)
Pages (from-to)2226-2232
Number of pages7
JournalJournal of Neuroscience
Issue number5
StatePublished - 2015


  • Brightness
  • CVEP
  • Color
  • Inhibition
  • Visual cortex
  • Visual perception

ASJC Scopus subject areas

  • General Neuroscience


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