Fig. 6.

Example of broadband gamma activity for different referencing methods for four channels in Subject 8. (A) Broadband gamma power using monopolar reference (red traces). (B) Broadband gamma power using Laplacian re-reference (blue traces). The EMG signal during the same trial is also shown (green trace). The black dashed line indicates EMG onset. Arrows indicate the times of substantial artifacts in (A) that are practically absent in (B). The variance of broadband gamma accounted for by the EMG activity (R²) is shown below the traces, and increases substantially for Laplacian re-referencing.