Mid-latency evoked potentials in self-reported impulsive aggression

The present study was conducted to examine psychophysiological differences in arousability among individuals who display impulsive aggressive outburst s. Amplitude and latency for the mid-latency evoked potentials (P1, N1 and P2) were obtained at scalp electrode sites. The evoking stimuli were three intensities (low, medium, high) of photic stimulation. Compared to non-aggr essive controls, impulsive aggressive subjects showed significantly reduced P1 amplitude, which is indicative of an inefficient sensory gating mechani sm. In addition, these subjects exhibited significantly larger N1 amplitude implying an enhanced orienting of attention to stimuli. Impulsive aggressi ve subjects also exhibited shorter P1, N1 and P2 peak latency. These result s suggest that impulsive aggressive individuals may display quicker orienti ng and processing of stimuli in an attempt to compensate for low resting ar ousal levels. Finally, impulsive aggressive subjects augmented the P1-N1 co mponent more frequently than controls, which is consistent with previous st udies examining impulsivity and sensation seeking. Together, these findings extend previous work concerning the underlying physiology of impulsive agg ression. It has been suggested that impulsive aggressive individuals may at tempt to compensate for low resting arousal levels by engaging in stimulus seeking behaviors. Accordingly, the present findings imply similar physiolo gical compensatory responses as demonstrated by heightened orienting of att ention, processing and arousability. In addition, a compromised sensory gat ing system in impulsive aggressors may exacerbate such circumstances, and l ead to later cognitive processing deficits. (C) 2001 Elsevier Science B.V. All rights reserved.