Data were analyzed using SPM5 (Wellcome Department of Imaging Neuroscience, University College, London). Functional volumes were corrected for slice acquisition timing differences and rigid-body realigned to the initial volume of the first functional imaging scan to account for residual movement after prospective motion correction. Each subject’s high resolution anatomic image was co-registered to the reference functional volume, segmented into gray, white and CSF tissue, and nonlinear spatial transformation parameters from this segmentation were subsequently applied to transform functional image volumes into the Montreal Neurological Institute (MNI) coordinate space (isotropic 2 mm voxels). Normalized functional image volumes were smoothed by a 6 mm full-width at half-maximum (FWHM) isotropic Gaussian kernel.
