Open AccessCombined permutation test and mixed‐effect model for group average analysis in fMRI
Author(s) -
Mériaux Sébastien,
Roche Alexis,
DehaeneLambertz Ghislaine,
Thirion Bertrand,
Poline JeanBaptiste
Publication year - 2006
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.20251
Subject(s) - homoscedasticity , permutation (music) , test statistic , likelihood ratio test , score test , statistics , test (biology) , gaussian , sign test , mathematics , heteroscedasticity , psychology , statistical hypothesis testing , wilcoxon signed rank test , chemistry , paleontology , physics , acoustics , biology , computational chemistry , mann–whitney u test
In group average analyses, we generalize the classical one‐sample t test to account for heterogeneous within‐subject uncertainties associated with the estimated effects. Our test statistic is defined as the maximum likelihood ratio corresponding to a Gaussian mixed‐effect model. The test's significance level is calibrated using the same sign permutation framework as in Holmes et al., allowing for exact specificity control under a mild symmetry assumption about the subjects' distribution. Because our likelihood ratio test does not rely on homoscedasticity, it is potentially more sensitive than both the standard t test and its permutation‐based version. We present results from the Functional Imaging Analysis Contest 2005 dataset to support this claim. Hum Brain Mapp 27:402–410, 2006. © 2006 Wiley‐Liss, Inc.