FMRI (underlying image) to structural image (red lines)
Structural image (underlying image) to standard image (red lines)
FMRI (underlying image) to standard image (red lines)
Analysis was carried out using FEAT, the FMRIB Easy Analysis Tool. The following pre-statistics processing was applied; Motion correction using MCFLIRT [Jenkinson 2001]; spatial smoothing using a Gaussian kernel of FWHM 5mm; mean-based intensity normalisation of all volumes by the same factor; nonlinear highpass temporal filtering (Gaussian-weighted LSF straight line fitting, with sigma=50.0s). Statistical analysis was carried out using FILM (FMRIB's Improved Linear Model) with local autocorrelation correction [Woolrich 2000]. Z (Gaussianised T/F) statistic images were thresholded using clusters determined by Z>2.3 and a 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].
References
[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).
[Woolrich 2000] M.W. Woolrich, B.D. Ripley, J.M. Brady and S.M. Smith. Temporal Autocorrelation in Univariate Linear Modelling of FMRI Data. NeuroImage in submission 2001.
[Friston 1992] 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 1992:1(214-220).
[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 1992:12(900-918).
[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 1995:33(636-647).
[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).
Covariance matrix