Electroencephalography-based functional connectivity. Functional connectivity (FC) is based on the phase lag index, filtered in the alpha 2 band (Fp1, Fp2, A1, and A2 excluded). (A) Distribution map for average FC of a healthy subject. (B) Distribution map of average FC for an Alzheimer’s disease patient. (C), (D) Adjacency matrices of the control subject from (A) and the patient from (B), respectively, showing the strength of the pair-wise FC values. X and Y axes, electrode number; cells, color-coded FC value of the corresponding electrode pair. Red, high FC value; blue, low FC value. FC is generally lower in the patient. Pictures generated with BrainWave software version 0.9.117 .