Figure 3.

Effects of the DAT1 3′ VNTR polymorphism on memory-related brain activity. A, The 9-repeat carriers show significantly higher memory-related midbrain activations than 10-repeat homozygous subjects. To verify the localization of the effect, the cluster of activation has been superimposed onto the normalized average of five MT images, on which the substantia nigra can be clearly distinguished from surrounding structures (Eckert et al., 2004). The substantia nigra has been segmented for illustrative purposes (green). B, The 9-repeat carriers also show significantly higher activations in the anterior cingulate (left) and in the basal forebrain (right) for subsequently remembered compared with subsequently forgotten items. Activations above a threshold of T > 2.72 (p < 0.005, uncorrected; extent threshold, k = 10 voxels) are displayed. Bar plots depict peak percentages of signal change of the canonical HRFs (SPM betas for subsequently remembered − subsequently forgotten items; scaled to the HRF) and their SEs for both groups, separately for the deep and shallow study conditions. [x, y, z], Voxel coordinates in MNI reference space.