17.6
zstat1 - C1
zstat2 - C2
zfstat1 - F1 (C1 & C2)
Analysis was carried out using FEAT (FMRI Expert Analysis Tool) Version 5.00, 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=50.0s). Time-series statistical analysis was carried out using FILM (FMRIB's Improved Linear Model) 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=0.01 [Worsley 1992, Friston 1994, Forman 1995]. 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 (in press) 2002.
[Smith 2002] S. Smith. Fast Robust Automated Brain Extraction. Human Brain Mapping (in press) 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.
[Friston 1994] K.J. Friston, K.J. Worsley, R.S.J. Frakowiak, J.C. Mazziotta and A.C. Evans. Assessing the significance of
focal activations using their spatial extent. Human Brain Mapping 1(214-220) 1994.
[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.
[Forman 1995] S.D Forman, J.D. Cohen, M. Fitzgerald, W.F. Eddy, M.A. Mintun and D.C. Noll.
Improved assessment of significant activation in functional magnetic resonance imaging (fMRI): Use of a cluster-size threshold.
Magnetic Resonance in Medicine 33(636-647) 1995.
[Jenkinson 2001] M. Jenkinson and S.M. Smith. A Global Optimisation Method for Robust Affine Registration of Brain Images. Medical Image Analysis 2001:5(2)(143-156).
[Jenkinson 2002] M. Jenkinson, P. Bannister, M. Brady and S. Smith. Improved Optimisation for the Robust and Accurate Linear Registration and Motion Correction of Brain Images. Neuroimage 2002: in publication.
Design matrix
Covariance matrix