We will now prepare the final areas of the face.
Firstly, swab the point directly in the centre of the forehead.
Next, swab the areas directly up from the outer edge of the participant's eyebrows, just below the hairline (or perhaps where the hairline used to be…).
Abrade all three areas.
Since the central area will be the location of the final and most important of our reference electrodes, and the upper forehead areas will be the first of our EEG (brainwave-recording) electrodes, it would be wise to spend extra time abrading these sites.