Effect of dopaminergic drugs (methylphenidate and sulpiride) on atypical brain activation; treatment Group A, n = 12. Top, right prefrontal and left ventral occipital regions that demonstrated significant enhancement of periodic activation by methylphenidate; bottom, medial posterior parietal, anterior cingulate/SMA, left lateral premotor and temporoparietal regions that demonstrated significant enhancement of load response by methylphenidate and significant attenuation of load response by sulpiride. Significance testing is by a permutation test at suprathreshold voxel cluster level: clusterwise P < 0.01. At this size of test, we expect less than one false positive cluster per map.