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Categorical encoding of color in the brain

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posted on 2023-06-08, 17:27 authored by Chris BirdChris Bird, Samuel BerensSamuel Berens, Aidan J Horner, Anna FranklinAnna Franklin
The areas of the brain that encode color categorically have not yet been reliably identified. Here, we used functional MRI adaptation to identify neuronal populations that represent color categories irrespective of metric differences in color. Two colors were successively presented within a block of trials. The two colors were either from the same or different categories (e.g., “blue 1 and blue 2” or “blue 1 and green 1”), and the size of the hue difference was varied. Participants performed a target detection task unrelated to the difference in color. In the middle frontal gyrus of both hemispheres and to a lesser extent, the cerebellum, blood-oxygen level-dependent response was greater for colors from different categories relative to colors from the same category. Importantly, activation in these regions was not modulated by the size of the hue difference, suggesting that neurons in these regions represent color categorically, regardless of metric color difference. Representational similarity analyses, which investigated the similarity of the pattern of activity across local groups of voxels, identified other regions of the brain (including the visual cortex), which responded to metric but not categorical color differences. Therefore, categorical and metric hue differences appear to be coded in qualitatively different ways and in different brain regions. These findings have implications for the long-standing debate on the origin and nature of color categories, and also further our understanding of how color is processed by the brain.

History

Publication status

  • Published

File Version

  • Published version

Journal

Proceedings of the National Academy of Sciences of the United States of America (PNAS) ISSN 1091-6490

ISSN

0027-8424

Publisher

National Academy of Sciences

Issue

12

Volume

111

Page range

4590-4595

Department affiliated with

  • Psychology Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2014-06-02

First Open Access (FOA) Date

2019-03-29

First Compliant Deposit (FCD) Date

2014-05-31

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