Example of an electroencephalography-based minimum spanning tree of a healthy subject. (A) Part of one of the four electroencephalography epochs used for the analysis. Every line is the time series of one electrode. (B) Phase lag index-based functional connectivity adjacency matrix with the functional connectivity values of each electrode pair. (C) Minimum spanning tree matrix derived from the matrix in (B) showing only the highest 20 connectivity values of the network without loops. (D) Graphic representation of (C), colors indicate different network modules. Pictures generated with BrainWave software version 0.9.117 (A, B, C) or Gephi version 0.8.2 (D).