Intensity dependence of auditory evoked N1/P2 component and personality.

The slope of the amplitude/stimulus intensity function (ASF) of sensory evoked potentials was found to be related to 'action-oriented' personality traits like 'sensation seeking', 'extraversion', and 'impulsivity'. We studied the ASF slope of the auditory evoked N1/P2 component as well as short-term ASF slope changes and their relationship to a German personality inventory (Freiburger Persönlichkeits-Inventar) in 33 healthy subjects. The ASF slope correlated negatively with 'life contentment' and positively with 'stress' in the first run. Stronger associations, however, were noted between slope changes within one test session and personality. Subjects scoring high on the second-order factor 'aggressive excitability' were characterized by a slope decrease from the first to the second run, following a 20-min interval. This finding of personality-dependent test-retest changes of the ASF slope stresses the importance of monitoring the duration of the recording when studying ASF slopes and offers an explanation for inconsistencies in the literature concerning cross-modal correlations in visual and auditory ASF slopes. The hypothesis is proposed that the serotonergic system, which has been related to 'action-oriented' personality, is involved in the modulation of the intensity dependence of the auditory evoked N1/P2 component.