Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain
Neuroscientists have long debated whether some regions of the human brain are exclusively engaged in a single specific mental process. Consistent with this view, fMRI has revealed cortical regions that respond selectively to certain stimulus classes such as faces. However, results from multivoxel pa...
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| Format: | Article |
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National Academy of Sciences (U.S.)
2018
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| Online Access: | http://hdl.handle.net/1721.1/114825 https://orcid.org/0000-0002-4514-0299 https://orcid.org/0000-0002-2191-0340 https://orcid.org/0000-0003-3853-7885 |
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| author | Schalk, Gerwin Kapeller, Christoph Guger, Christoph Ogawa, Hiroshi Hiroshima, Satoru Kamada, Kyousuke Lafer-Sousa, Rosa Saygin, Zeynep M. Kanwisher, Nancy |
| author2 | Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences Schalk, Gerwin Kapeller, Christoph Guger, Christoph Ogawa, Hiroshi Hiroshima, Satoru Kamada, Kyousuke Lafer-Sousa, Rosa Saygin, Zeynep M. Kanwisher, Nancy |
| author_sort | Schalk, Gerwin |
| collection | MIT |
| description | Neuroscientists have long debated whether some regions of the human brain are exclusively engaged in a single specific mental process. Consistent with this view, fMRI has revealed cortical regions that respond selectively to certain stimulus classes such as faces. However, results from multivoxel pattern analyses (MVPA) challenge this view by demonstrating that category-selective regions often contain information about “nonpreferred” stimulus dimensions. But is this nonpreferred information causally relevant to behavior? Here we report a rare opportunity to test this question in a neurosurgical patient implanted for clinical reasons with strips of electrodes along his fusiform gyri. Broadband gamma electrocorticographic responses in multiple adjacent electrodes showed strong selectivity for faces in a region corresponding to the fusiform face area (FFA), and preferential responses to color in a nearby site, replicating earlier reports. To test the causal role of these regions in the perception of nonpreferred dimensions, we then electrically stimulated individual sites while the patient viewed various objects. When stimulated in the FFA, the patient reported seeing an illusory face (or “facephene”), independent of the object viewed. Similarly, stimulation of color-preferring sites produced illusory “rainbows.” Crucially, the patient reported no change in the object viewed, apart from the facephenes and rainbows apparently superimposed on them. The functional and anatomical specificity of these effects indicate that some cortical regions are exclusively causally engaged in a single specific mental process, and prompt caution about the widespread assumption that any information scientists can decode from the brain is causally relevant to behavior. |
| first_indexed | 2024-09-23T13:54:17Z |
| format | Article |
| id | mit-1721.1/114825 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T13:54:17Z |
| publishDate | 2018 |
| publisher | National Academy of Sciences (U.S.) |
| record_format | dspace |
| spelling | mit-1721.1/1148252022-09-28T16:57:58Z Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain Schalk, Gerwin Kapeller, Christoph Guger, Christoph Ogawa, Hiroshi Hiroshima, Satoru Kamada, Kyousuke Lafer-Sousa, Rosa Saygin, Zeynep M. Kanwisher, Nancy Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences McGovern Institute for Brain Research at MIT Lafer-Sousa, Rosa Saygin, Zeynep M. Kanwisher, Nancy Neuroscientists have long debated whether some regions of the human brain are exclusively engaged in a single specific mental process. Consistent with this view, fMRI has revealed cortical regions that respond selectively to certain stimulus classes such as faces. However, results from multivoxel pattern analyses (MVPA) challenge this view by demonstrating that category-selective regions often contain information about “nonpreferred” stimulus dimensions. But is this nonpreferred information causally relevant to behavior? Here we report a rare opportunity to test this question in a neurosurgical patient implanted for clinical reasons with strips of electrodes along his fusiform gyri. Broadband gamma electrocorticographic responses in multiple adjacent electrodes showed strong selectivity for faces in a region corresponding to the fusiform face area (FFA), and preferential responses to color in a nearby site, replicating earlier reports. To test the causal role of these regions in the perception of nonpreferred dimensions, we then electrically stimulated individual sites while the patient viewed various objects. When stimulated in the FFA, the patient reported seeing an illusory face (or “facephene”), independent of the object viewed. Similarly, stimulation of color-preferring sites produced illusory “rainbows.” Crucially, the patient reported no change in the object viewed, apart from the facephenes and rainbows apparently superimposed on them. The functional and anatomical specificity of these effects indicate that some cortical regions are exclusively causally engaged in a single specific mental process, and prompt caution about the widespread assumption that any information scientists can decode from the brain is causally relevant to behavior. National Institutes of Health (U.S.) (Grant DP1HD091947) 2018-04-20T19:12:48Z 2018-04-20T19:12:48Z 2017-10 2018-04-19T15:19:15Z Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 http://hdl.handle.net/1721.1/114825 Schalk, Gerwin et al. “Facephenes and Rainbows: Causal Evidence for Functional and Anatomical Specificity of Face and Color Processing in the Human Brain.” Proceedings of the National Academy of Sciences 114, 46 (October 2017): 12285–12290 © 2017 National Academy of Sciences https://orcid.org/0000-0002-4514-0299 https://orcid.org/0000-0002-2191-0340 https://orcid.org/0000-0003-3853-7885 http://dx.doi.org/10.1073/PNAS.1713447114 Proceedings of the National Academy of Sciences Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf National Academy of Sciences (U.S.) PNAS |
| spellingShingle | Schalk, Gerwin Kapeller, Christoph Guger, Christoph Ogawa, Hiroshi Hiroshima, Satoru Kamada, Kyousuke Lafer-Sousa, Rosa Saygin, Zeynep M. Kanwisher, Nancy Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title | Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title_full | Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title_fullStr | Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title_full_unstemmed | Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title_short | Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| title_sort | facephenes and rainbows causal evidence for functional and anatomical specificity of face and color processing in the human brain |
| url | http://hdl.handle.net/1721.1/114825 https://orcid.org/0000-0002-4514-0299 https://orcid.org/0000-0002-2191-0340 https://orcid.org/0000-0003-3853-7885 |
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