to differentiate P3 subcomponents and most used a two-stimulus oddball task, which yields a weaker frontal P3a than the novelty oddball task (Polich and Criado, 2006). We have previously argued that simple oddball tasks are not challenging enough to elicit robust P3b reductions in depressed patients having subtle cognitive deficits. Larger differences in P3b between depressed patients and controls may be found by increasing the cognitive demands of the task (e.g., Bruder et al., 1995; Pierson et al., 1996).
