Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding
A long-standing debate exists on how our brain assigns the fine-grained perceptual representation of color into discrete color categories. Recent functional magnetic resonance imaging (fMRI) studies have identified several regions as the candidate loci of color categorization, including the visual c...
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Frontiers Media S.A.
2021-07-01
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| Series: | Frontiers in Neuroscience |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnins.2021.679627/full |
| _version_ | 1818354363807039488 |
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| author | Mengdan Sun Luming Hu Xiaoyang Xin Xuemin Zhang Xuemin Zhang |
| author_facet | Mengdan Sun Luming Hu Xiaoyang Xin Xuemin Zhang Xuemin Zhang |
| author_sort | Mengdan Sun |
| collection | DOAJ |
| description | A long-standing debate exists on how our brain assigns the fine-grained perceptual representation of color into discrete color categories. Recent functional magnetic resonance imaging (fMRI) studies have identified several regions as the candidate loci of color categorization, including the visual cortex, language-related areas, and non-language-related frontal regions, but the evidence is mixed. Distinct from most studies that emphasized the representational differences between color categories, the current study focused on the variability among members within a category (e.g., category prototypes and boundaries) to reveal category encoding in the brain. We compared and modeled brain activities evoked by color stimuli with varying distances from the category boundary in an active categorization task. The frontal areas, including the inferior and middle frontal gyri, medial superior frontal cortices, and insular cortices, showed larger responses for colors near the category boundary than those far from the boundary. In addition, the visual cortex encodes both within-category variability and cross-category differences. The left V1 in the calcarine showed greater responses to colors at the category center than to those far from the boundary, and the bilateral V4 showed enhanced responses for colors at the category center as well as colors around the boundary. The additional representational similarity analyses (RSA) revealed that the bilateral insulae and V4a carried information about cross-category differences, as cross-category colors exhibited larger dissimilarities in brain patterns than within-category colors. Our study suggested a hierarchically organized network in the human brain during active color categorization, with frontal (both lateral and medial) areas supporting domain-general decisional processes and the visual cortex encoding category structure and differences, likely due to top-down modulation. |
| first_indexed | 2024-12-13T19:24:14Z |
| format | Article |
| id | doaj.art-82bd56f09bb941eea22cca5aeed12fdc |
| institution | Directory Open Access Journal |
| issn | 1662-453X |
| language | English |
| last_indexed | 2024-12-13T19:24:14Z |
| publishDate | 2021-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroscience |
| spelling | doaj.art-82bd56f09bb941eea22cca5aeed12fdc2022-12-21T23:34:05ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2021-07-011510.3389/fnins.2021.679627679627Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary EncodingMengdan Sun0Luming Hu1Xiaoyang Xin2Xuemin Zhang3Xuemin Zhang4Center for Psychological Sciences, Zhejiang University, Hangzhou, ChinaBeijing Key Laboratory of Applied Experimental Psychology, Faculty of Psychology, National Demonstration Center for Experimental Psychology Education, Beijing Normal University, Beijing, ChinaCenter for Psychological Sciences, Zhejiang University, Hangzhou, ChinaBeijing Key Laboratory of Applied Experimental Psychology, Faculty of Psychology, National Demonstration Center for Experimental Psychology Education, Beijing Normal University, Beijing, ChinaState Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, ChinaA long-standing debate exists on how our brain assigns the fine-grained perceptual representation of color into discrete color categories. Recent functional magnetic resonance imaging (fMRI) studies have identified several regions as the candidate loci of color categorization, including the visual cortex, language-related areas, and non-language-related frontal regions, but the evidence is mixed. Distinct from most studies that emphasized the representational differences between color categories, the current study focused on the variability among members within a category (e.g., category prototypes and boundaries) to reveal category encoding in the brain. We compared and modeled brain activities evoked by color stimuli with varying distances from the category boundary in an active categorization task. The frontal areas, including the inferior and middle frontal gyri, medial superior frontal cortices, and insular cortices, showed larger responses for colors near the category boundary than those far from the boundary. In addition, the visual cortex encodes both within-category variability and cross-category differences. The left V1 in the calcarine showed greater responses to colors at the category center than to those far from the boundary, and the bilateral V4 showed enhanced responses for colors at the category center as well as colors around the boundary. The additional representational similarity analyses (RSA) revealed that the bilateral insulae and V4a carried information about cross-category differences, as cross-category colors exhibited larger dissimilarities in brain patterns than within-category colors. Our study suggested a hierarchically organized network in the human brain during active color categorization, with frontal (both lateral and medial) areas supporting domain-general decisional processes and the visual cortex encoding category structure and differences, likely due to top-down modulation.https://www.frontiersin.org/articles/10.3389/fnins.2021.679627/fullcolor perceptioncategorizationfMRIfrontalcategorical structurevisual cortex |
| spellingShingle | Mengdan Sun Luming Hu Xiaoyang Xin Xuemin Zhang Xuemin Zhang Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding Frontiers in Neuroscience color perception categorization fMRI frontal categorical structure visual cortex |
| title | Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding |
| title_full | Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding |
| title_fullStr | Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding |
| title_full_unstemmed | Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding |
| title_short | Neural Hierarchy of Color Categorization: From Prototype Encoding to Boundary Encoding |
| title_sort | neural hierarchy of color categorization from prototype encoding to boundary encoding |
| topic | color perception categorization fMRI frontal categorical structure visual cortex |
| url | https://www.frontiersin.org/articles/10.3389/fnins.2021.679627/full |
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