Figure 2.

Electrode configuration for classroom and laboratory exercises. A. Standard electrode placement locations according to the 10–20 electrode system. B. For the alpha wave experiments, electrodes were placed at locations O1 and O2, using an adhesive electrode at the mastoid process as ground. C. Electrodes placed at locations Pz and P4 for the Laboratory Oddball Task, with a ground electrode at the mastoid process. For Classroom exercises, one recording electrode was sacrificed, and instead, an additional mastoid ground was used. We recorded from Pz comparing to the two references, on left and right mastoid processes.