Auditory evoked dipole source activity: indicator of central serotonergic dysfunction in psychiatric patients?

Event-related potentials reflect postsynaptic effects of cortical neurotransmitters and may be useful as indicators of the function of neurochemical systems. Arguments are presented for the hypothesis that the stimulus-intensity dependence of the auditory-evoked N1/P2 component may be a noninvasive indicator of behaviorally relevant aspects of central serotonergic activity. Converging evidence from our own studies as well as from the literature suggest that a pronounced intensity dependence of this component reflects low central serotonergic neurotransmission and vice versa. Dipole source analysis represents an important methodological advance in this context, because N1/P2 subcomponents generated by different cortical structures with different serotonergic innervation can be separated.