supporting the hypothesis that P3a is related to frontal attention mechanisms mediated by dopaminergic activity, whereas P3b is related to temporoparietal activity mediated by the norepinephrine system. Although further research on the neurotransmitter systems mediating P3 is needed, the widespread neural networks that appear to underlie P3a and P3b suggest that both noradrenergic and dopaminergic neurotransmitter systems are likely to be of importance. Studies could, for instance, investigate whether antidepressants that block reuptake of norepinephrine, e.g., bupropion, normalize P3a or novelty P3 in depressed patients. The possible value of novelty P3 for predicting clinical responsiveness to these antidepressants that act on the noradrenergic system could also be investigated in this context.
