Monopolar (or referential) montages are channels in which one electrode (usually the active, but that’s not necessarily true) is placed over an active EEG site on the head. Bipolar (or sequential) montages are channels in which BOTH active and reference electrode are placed over active EEG sites. T3/A1 has one electrode over a head site and one over a relatively inert site (the earlobe), so it is monopolar. T3/T4 has both electrodes over head sites, so it is bipolar. A […]