Analysis was carried out using FEAT (FMRI Expert Analysis Tool) Version 5.43, part of FSL (FMRIB's Software Library, www.fmrib.ox.ac.uk/fsl). The following pre-statistics processing was applied; motion correction using MCFLIRT [Jenkinson 2002]; non-brain removal using BET [Smith 2002]; spatial smoothing using a Gaussian kernel of FWHM 5mm; mean-based intensity normalisation of all volumes by the same factor; highpass temporal filtering (Gaussian-weighted LSF straight line fitting, with sigma=22.5s). Time-series statistical analysis was carried out using FILM with local autocorrelation correction [Woolrich 2001]. Z (Gaussianised T/F) statistic images were thresholded using clusters determined by Z>2.3 and a (corrected) cluster significance threshold of P=0.05 [Worsley 1992]. Registration to high resolution and/or standard images was carried out using FLIRT [Jenkinson 2001, 2002].
References
[Jenkinson 2002] M. Jenkinson and P. Bannister and M. Brady and S. Smith. Improved optimisation for the robust and accurate linear registration and motion correction of brain images. NeuroImage 17:2(825-841) 2002.
[Smith 2002] S. Smith. Fast Robust Automated Brain Extraction. Human Brain Mapping 17:3(143-155) 2002.
[Woolrich 2001] M.W. Woolrich, B.D. Ripley, J.M. Brady and S.M. Smith. Temporal Autocorrelation in Univariate Linear Modelling of FMRI Data. NeuroImage 14:6(1370-1386) 2001.
[Worsley 1992] K.J. Worsley, A.C. Evans, S. Marrett and P. Neelin. A three-dimensional statistical analysis
for CBF activation studies in human brain. Journal of Cerebral Blood Flow and Metabolism 12(900-918) 1992.
[Jenkinson 2001] M. Jenkinson and S.M. Smith. A Global Optimisation Method for Robust Affine Registration of Brain Images. Medical Image Analysis 5:2(143-156) 2001.
Covariance matrix