Color Compensation in Anomalous Trichromats Assessed with fMRI

Katherine E.M. Tregillus, Zoey J. Isherwood, John E. Vanston, Stephen A. Engel, Donald I.A. MacLeod, Ichiro Kuriki, Michael A. Webster

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Anomalous trichromacy is a common form of congenital color deficiency resulting from a genetic alteration in the photopigments of the eye's light receptors. The changes reduce sensitivity to reddish and greenish hues, yet previous work suggests that these observers may experience the world to be more colorful than their altered receptor sensitivities would predict, potentially indicating an amplification of post-receptoral signals. However, past evidence suggesting such a gain adjustment rests on subjective measures of color appearance or salience. We directly tested for neural amplification by using fMRI to measure cortical responses in color-anomalous and normal control observers. Color contrast response functions were measured in two experiments with different tasks to control for attentional factors. Both experiments showed a predictable reduction in chromatic responses for anomalous trichromats in primary visual cortex. However, in later areas V2v and V3v, chromatic responses in the two groups were indistinguishable. Our results provide direct evidence for neural plasticity that compensates for the deficiency in the initial receptor color signals and suggest that the site of this compensation is in early visual cortex. Tregillus et al. report fMRI findings that anomalous trichromats (people with a common color vision deficiency) show compensation in early visual cortex for their reduced red/green sensitivity. BOLD responses in these participants are reduced in V1 compared to controls but are elevated in V2 and V3, despite their poor performance near threshold.

Original languageEnglish
Pages (from-to)936-942.e4
JournalCurrent Biology
Issue number5
Publication statusPublished - 2021 Mar 8


  • adaptation
  • anomalous trichromacy
  • attention
  • color blindness
  • color vision
  • color vision deficiency
  • compensation
  • early visual cortex
  • fMRI
  • plasticity

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)


Dive into the research topics of 'Color Compensation in Anomalous Trichromats Assessed with fMRI'. Together they form a unique fingerprint.

Cite this