Fig. 3.

Voxel-wise correlation between category fluency and locus coeruleus volume. Results of voxel-wise multiple regression correlating brain volume with category fluency performance in the MCI (n = 542) group with covariates for total intracranial volume, age, sex, education, APOE-ε4 carrier status, and MRI magnet strength. (a) Significant clusters emerged overlapping the bilateral locus coeruleus and right lateral midbrain at an uncorrected height threshold of p < 0.05. (b) Significant clusters at p < 0.05 (orange) overlaid on an unthresholded statistical map (red). Explicit mask comprising the midbrain and pons was applied to limit search volume to rostral brainstem structures. Images are shown in neurological orientation. Text indicates MNI coordinates of corresponding axial slices. Abbreviations: APOE-ε4 = apolipoprotein ε4, MCI = mild cognitive impairment, MNI = Montreal Neurological Institute