Analysis methods
FMRI data processing was carried out using FEAT (FMRI Expert Analysis Tool) Version 6.00, part of FSL (FMRIB's Software Library, www.fmrib.ox.ac.uk/fsl). The following pre-statistics processing was applied; non-brain removal using BET [Smith 2002]; spatial smoothing using a Gaussian kernel of FWHM 4.0mm; grand-mean intensity normalisation of the entire 4D dataset by a single multiplicative factor; highpass temporal filtering (Gaussian-weighted least-squares straight line fitting, with sigma=75.0s).
References
[Smith 2002] S. Smith. Fast Robust Automated Brain Extraction. Human Brain Mapping 17:3(143-155) 2002.