Initial preprocessing steps, implemented in Automated Image Registration software (http://bishopw.loni.ucla.edu/AIR), were slice-time and motion correction, and removal of linear trends and significant time series outliers. The images were then spatially normalized using a nonlinear algorithm and spatially smoothed (8-mm full-width at half-maximum Gaussian kernel) using SPM5 (http://www.fil.ion.ucl.ac.uk/spm/software).
