Inferior frontal approach to the nucleus accumbens (NA). (a) Human brain, right cerebral hemisphere, coronal section 2 mm anterior to the AC and right hemi-skull, internal surface (coloured bones of the visceral skull). (b) Human brain, right cerebral hemisphere (removed frontal and parietal opercula), coronal section 2 mm anterior to the AC and skull (removed parts of the frontal and parietal bones, coloured bones of the skull).