P300 EVENT-RELATED POTENTIAL HERITABILITY IN MONOZYGOTIC AND DIZYGOTIC TWINS

The present study examined the heritability of the P3 waveform and the N1, P2, and N2 components by assessing the visual event-related poten tial (ERP) of 30 monozygotic (MZ) and 34 dizygotic (DZ) twin pairs. El ectroencephalogram activity was recorded from Pz, P3, and P4 scalp sit es while individuals performed a reaction time task involving two cond itions differing in difficulty. Genetic modeling indicated substantial genetic influence on P3 amplitude, P3 latency, and manual reaction ti me for the difficult condition. No significant heritability was found for the latency of P3 or manual reaction time for the easy condition, but P3 amplitude was heritable for this condition. The amplitude of th e early components (N1, P2, and N2) was heritable, but no significant genetic influences were found for the latency of these components. Com pared with the DZ twins, the greater similarity of the MZ pairs on the event-related potential measures was not due to their greater similar ity in either head dimensions or mental ability, despite the facts tha t IQ scores were weakly correlated with P3 and N2 amplitude and that a mplitude and latency were related to some measures of head size. These findings suggest that P3 amplitude and the amplitude of earlier ERP c omponents are under partial genetic control, supporting the notion tha t these ERP components could perhaps be used to identify genetic risk for psychopathology.