For both spontaneous and evoked potentials, we use electrode systems from EASYCAP GmbH (Herrsching, Germany). All electrodes are sintered Ag/AgCl Multitrode flat disks. For evoked-potential? studies, we use custom-fabricated caps. These caps are standard in that they contain 29 Multitrode B18-LU-150-MEG compatible electrodes in a standard 10-20 system array, as well as 3 Multitrode B18-HU-200-MEG electrodes for monitoring ocular signals, one Multitrode B18-LU-150-MEG ground electrode, and one Multitrode B18-LU-150-MEG reference electrode.