Image analysis will be performed on a personal computer station (DELL inc, Round Rock, Texas, USA) using the "statistical parametric mapping" package (SPM2, Wellcome Department of Cognitive Neurology, London, United Kingdom). Images of each subject will be realigned to the first volume and normalized to the MNI standard proportional stereotaxic space, which is based on that of Talairach and Tournoux (1988). The images will be coregistered on a template and spatially smoothed with a Gaussian kernel of 12 mm full width at half maximum (FWHM) to take into account variations in gyral anatomy and individual variability in structure-function relationships, and to improve the signal-to-noise ratio.