Comparison of VFT results between the depressed group and healthy control. Upper panels: The locations of the 44 channels on the head are indicated by yellow dots. The frontal cortex is on the left; the parietal cortex on the right. Significant differences are observed in 6 of the 44 channels indicated by red circles. Lower panels: Grand average waveforms of changes in [oxy-Hb] of CH 3 (left) and CH 34 (right) in the three groups, both of which show significant differences. Blue line, healthy controls; red line, AD group; black line, depressed group. In all three groups, during the rest period from -30 to 0 s, there are slight changes in [oxy-Hb], and during the task period from 0 to 60 s, [oxy-Hb] associated with brain activation is increased. At 60 s (when the task concluded), [oxy-Hb] is decreased. Abbreviations: D, depression; AD, Alzheimer’s disease.