Hub region’s distribution in normal control (NC), mild cognitive impairment (MCI), and Alzheimer’s disease (AD). (A) Axial, (B) coronal, and (C) sagittal. Hub regions in NC (red), MCI (yellow), and AD (green). Cyan indicated common hub in NC and MCI. Blue indicated common hub in MCI and AD. Sphere size was decided by the region’s betweenness values. L indicates left; R, right.