The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI
A wide range of studies show the capacity of multivariate statistical methods for fMRI to improve mapping of brain activations in a noisy environment. An advanced method uses local canonical correlation analysis (CCA) to encompass a group of neighboring voxels instead of looking at the single voxel...
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| Format: | Article |
| Language: | English |
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Wiley
2012-01-01
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| Series: | International Journal of Biomedical Imaging |
| Online Access: | http://dx.doi.org/10.1155/2012/738283 |
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| _version_ | 1832566705885282304 |
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| author | Dietmar Cordes Mingwu Jin Tim Curran Rajesh Nandy |
| author_facet | Dietmar Cordes Mingwu Jin Tim Curran Rajesh Nandy |
| author_sort | Dietmar Cordes |
| collection | DOAJ |
| description | A wide range of studies show the capacity of multivariate statistical methods for fMRI to improve mapping of brain activations in a noisy environment. An advanced method uses local canonical correlation analysis (CCA) to encompass a group of neighboring voxels instead of looking at the single voxel time course. The value of a suitable test statistic is used as a measure of activation. It is customary to assign the value to the center voxel; however, this is a choice of convenience and without constraints introduces artifacts, especially in regions of strong localized activation. To compensate for these deficiencies, different spatial constraints in CCA have been introduced to enforce dominance of the center voxel. However, even if the dominance condition for the center voxel is satisfied, constrained CCA can still lead to a smoothing artifact, often called the “bleeding artifact of CCA”, in fMRI activation patterns. In this paper a new method is introduced to measure and correct for the smoothing artifact for constrained CCA methods. It is shown that constrained CCA methods corrected for the smoothing artifact lead to more plausible activation patterns in fMRI as shown using data from a motor task and a memory task. |
| format | Article |
| id | doaj-art-c5fb4c243c69483180392f9dea9e265a |
| institution | Kabale University |
| issn | 1687-4188 1687-4196 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Biomedical Imaging |
| spelling | doaj-art-c5fb4c243c69483180392f9dea9e265a2025-02-03T01:03:24ZengWileyInternational Journal of Biomedical Imaging1687-41881687-41962012-01-01201210.1155/2012/738283738283The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRIDietmar Cordes0Mingwu Jin1Tim Curran2Rajesh Nandy3Department of Physics, Ryerson University, Toronto, ON, M5B 2K3, CanadaDepartment of Radiology, University of Colorado, Denver, CO 80045, USADepartment of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USADepartments of Biostatistics and Psychology, UCLA, Los Angeles, CA 90095, USAA wide range of studies show the capacity of multivariate statistical methods for fMRI to improve mapping of brain activations in a noisy environment. An advanced method uses local canonical correlation analysis (CCA) to encompass a group of neighboring voxels instead of looking at the single voxel time course. The value of a suitable test statistic is used as a measure of activation. It is customary to assign the value to the center voxel; however, this is a choice of convenience and without constraints introduces artifacts, especially in regions of strong localized activation. To compensate for these deficiencies, different spatial constraints in CCA have been introduced to enforce dominance of the center voxel. However, even if the dominance condition for the center voxel is satisfied, constrained CCA can still lead to a smoothing artifact, often called the “bleeding artifact of CCA”, in fMRI activation patterns. In this paper a new method is introduced to measure and correct for the smoothing artifact for constrained CCA methods. It is shown that constrained CCA methods corrected for the smoothing artifact lead to more plausible activation patterns in fMRI as shown using data from a motor task and a memory task.http://dx.doi.org/10.1155/2012/738283 |
| spellingShingle | Dietmar Cordes Mingwu Jin Tim Curran Rajesh Nandy The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI International Journal of Biomedical Imaging |
| title | The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI |
| title_full | The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI |
| title_fullStr | The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI |
| title_full_unstemmed | The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI |
| title_short | The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI |
| title_sort | smoothing artifact of spatially constrained canonical correlation analysis in functional mri |
| url | http://dx.doi.org/10.1155/2012/738283 |
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