Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis

Parametric statistical methods, such as Z-, t-, and F-values, are traditionally employed in functional magnetic resonance imaging (fMRI) for identifying areas in the brain that are active with a certain degree of statistical significance. These parametric methods, however, have two major drawbacks....

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Main Authors: Anders Eklund, Mats Andersson, Hans Knutsson
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:International Journal of Biomedical Imaging
Online Access:http://dx.doi.org/10.1155/2011/627947
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author Anders Eklund
Mats Andersson
Hans Knutsson
author_facet Anders Eklund
Mats Andersson
Hans Knutsson
author_sort Anders Eklund
collection DOAJ
description Parametric statistical methods, such as Z-, t-, and F-values, are traditionally employed in functional magnetic resonance imaging (fMRI) for identifying areas in the brain that are active with a certain degree of statistical significance. These parametric methods, however, have two major drawbacks. First, it is assumed that the observed data are Gaussian distributed and independent; assumptions that generally are not valid for fMRI data. Second, the statistical test distribution can be derived theoretically only for very simple linear detection statistics. With nonparametric statistical methods, the two limitations described above can be overcome. The major drawback of non-parametric methods is the computational burden with processing times ranging from hours to days, which so far have made them impractical for routine use in single-subject fMRI analysis. In this work, it is shown how the computational power of cost-efficient graphics processing units (GPUs) can be used to speed up random permutation tests. A test with 10000 permutations takes less than a minute, making statistical analysis of advanced detection methods in fMRI practically feasible. To exemplify the permutation-based approach, brain activity maps generated by the general linear model (GLM) and canonical correlation analysis (CCA) are compared at the same significance level.
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spelling doaj-art-252d0a413deb409e949e3fb8d0c2c8cc2025-02-03T01:23:53ZengWileyInternational Journal of Biomedical Imaging1687-41881687-41962011-01-01201110.1155/2011/627947627947Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI AnalysisAnders Eklund0Mats Andersson1Hans Knutsson2Division of Medical Informatics, Department of Biomedical Engineering, Linköping University, Linköping, SwedenDivision of Medical Informatics, Department of Biomedical Engineering, Linköping University, Linköping, SwedenDivision of Medical Informatics, Department of Biomedical Engineering, Linköping University, Linköping, SwedenParametric statistical methods, such as Z-, t-, and F-values, are traditionally employed in functional magnetic resonance imaging (fMRI) for identifying areas in the brain that are active with a certain degree of statistical significance. These parametric methods, however, have two major drawbacks. First, it is assumed that the observed data are Gaussian distributed and independent; assumptions that generally are not valid for fMRI data. Second, the statistical test distribution can be derived theoretically only for very simple linear detection statistics. With nonparametric statistical methods, the two limitations described above can be overcome. The major drawback of non-parametric methods is the computational burden with processing times ranging from hours to days, which so far have made them impractical for routine use in single-subject fMRI analysis. In this work, it is shown how the computational power of cost-efficient graphics processing units (GPUs) can be used to speed up random permutation tests. A test with 10000 permutations takes less than a minute, making statistical analysis of advanced detection methods in fMRI practically feasible. To exemplify the permutation-based approach, brain activity maps generated by the general linear model (GLM) and canonical correlation analysis (CCA) are compared at the same significance level.http://dx.doi.org/10.1155/2011/627947
spellingShingle Anders Eklund
Mats Andersson
Hans Knutsson
Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
International Journal of Biomedical Imaging
title Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
title_full Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
title_fullStr Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
title_full_unstemmed Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
title_short Fast Random Permutation Tests Enable Objective Evaluation of Methods for Single-Subject fMRI Analysis
title_sort fast random permutation tests enable objective evaluation of methods for single subject fmri analysis
url http://dx.doi.org/10.1155/2011/627947
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