the Montreal Neurological Institute average MRI (MNI305), was also used. Within the FDM, conductivity values were 0.25 S/m(Siemens/meter) for the brain, 1.8 S/mfor the cerebral spinal fluid, 0.018 S/m for the skull, and 0.44 S/m for the scalp (Ferree, Eriksen, & Tucker, 2000). Distributed dipole placement relied on the probabilistic map of the MNI305 average brain. Within this probabilistic atlas, cortical gray matter was parceled into 7 mm voxels. Each dipole served as a source location with three orthogonal orientations, resulting in a total of 2,447 source dipole triplets. Resulting estimated source activation voxel intensities and orientations were displayed superimposed on MRI slice views of the Talairach-transformed Colin27 brain. Five source regions corresponding to the scalp ERP effects were selected based on previously published source analysis of error and feedback monitoring (Pizzagalli, Peccoralo, Davidson, & Cohen, 2006; Santesso, et al., 2011). Source waveforms within each Brodmann area (BA) were generated from the above models. These source waveforms were then analyzed using mean amplitude measures (nanoamperes) within Brodmann areas, averaged over the time course of the 200–350 msec ERP window used to capture the FRN. Specifically we focused on BA 10 (anterior prefrontal cortex/orbitofrontal cortex), BA 11 (orbitofrontal cortex), BA 24
