Flavanols enhance CBV-fMRI. (a) A voxel-based analysis of 37 individuals revealed that, compared with those in the low-flavanol condition, those in the high-flavanol condition showed a CBV increase in the body of the hippocampal circuit. A transverse slice, onto which the hippocampal circuit mask was applied, shows that the CBV increase localized primarily to the dentate gyrus and subiculum (bottom left; color coded for degree of significance). Single-subject line plots (right) show mean CBV in all voxels determined to have a significant group × time interaction (F1,33 = 27.58, P < 0.0001). (b) A voxel-based analysis of 35 individuals revealed that better performance on the ModBent task correlated with greater CBV in the body of the right hippocampal circuit (top left). A transverse slice, onto which the hippocampal circuit mask was applied, shows that the correlation localized primarily to the dentate gyrus (bottom left; color coded for degree of significance). A scatter plot (right) shows the association between change in ModBent performance and single-subject mean change in CBV from all significantly correlated voxels (β = −0.554, r2 = 0.307, P < 0.001).