A 3T Siemens Trio whole-body scanner (Siemens, Erlangen) was used to acquire structural MRI images. For each subject, two high-resolution 3D MP-RAGE T1-weighted sequences that optimize contrast for a range of tissue properties were obtained with the following parameters: TR = 2.53 s, TE = 3.25 ms, flip angle = 7°, FOV = 256, 128 sagittal slices, 1.33 mm thickness, in-plane resolution 1 mm × 1 mm. These images were used to reconstruct each person’s cortical surface (Dale et al., 1999; Fischl et al., 1999a). Inner skull surface was derived from the segmented MRI data and used for a boundary element model of the volume conductor in the forward calculations. The gray–white matter surface was morphed into average space (Fischl et al., 1999b) and decimated, thereby defining the solution space with 5124 free-rotating dipoles spaced ∼7 mm.
