EEG and cardiac correlates of neuroticism: a psychophysiological comparison of neurotics and normal controls in relation to personality.

In the context of Eysenck's theory of personality the contingent negative variation (CNV) was recorded in 60 psychiatric patients (30 introverted and 30 extraverted neurotics) and 60 normal controls (30 stable extraverts and 30 stable introverts) under three experimental conditions, i.e. the standard CNV-paradigm (St: tone-light-MR) and two discrimination tasks. In these tasks either S1 (info S1) or S2 (info S2) contained task-relevant information with respect to the motor response (MR). At a 4 sec CNV-interval the O- and E-wave, the P300 elicited by S1, the alpha power, the heart rate and the heart rate variability were measured. The EEG, recorded from Cz to the linked earlobes, P4 vs. O2 and the EOG were sampled at a frequency of 100 c/s over a 12 sec epoch (starting 8 sec before S1 till the onset of S2). The increase in informative properties of S1 (as is the case during 'info S1') resulted in enhanced amplitudes (and increased latencies) of O-wave and P300, producing evidence that these two slow waves are related to cortical orientation. The E-wave is not influenced, as expected, by the informative properties of 'info S2' and there is no linear relationship between task complexity and the E-wave. Reaction time increased from 'St' to 'info S2' as did the heart rate. The present results indicate that there is no simple way to characterize CNV-components that can best distinguish neurotics from controls. Neurotics showed during all three conditions shorter P300 latencies than controls indicating that the P300 seems to be a better ERP-parameter than the CNV-components to differentiate between neurotics and controls.