Neurochemical modulation of cortical information processing – P300 event related potential and striatal dopamine

The P300 event related potential (ERP) is related to cognitive functions and central information processing. Clinical and genetic investigations suggest that dopaminergic neurons could be involved in the generation of the P300. However, there is no direct evidence in vivo that P300 amplitudes and latencies are related to dopaminergic parameters. Aim of this study was to elucidate dopaminergic aspects of the P300 ERP by combining neurophysiological and nuclear medicine techniques. Patients with major depressive episode underwent both P300 recordings and dynamic [123I] IBZM SPECT for the evaluation of striatal dopamine D2/D3-receptor availability. There were significant positive correlations of the striatal dopamine D2/D3-receptor status with P300 amplitudes (Pearson's r = 0.746; p < 0.01) and negative correlations with P300 latencies (r = −0.761; p < 0.01). This combined approach presents in vivo evidence that the dopaminergic system might play an important role in the generation of the P300 and that central dopaminergic activity could be involved in the modulation of P300 parameters. This might be of relevance for the interpretation of P300 studies in psychiatric disorders with dopamine related pathophysiology.