P3a and mismatch negativity in individuals with moderate Intermittent Explosive Disorder.

The mismatch negativity (MMN) and the P3a have so far only sparsely been used to investigate neural correlates of impulsivity. This study compares the MMN, P3a, and P3b between individuals with and without the propensity for impulsive, uncontrollable outbursts of temper (referred to here as moderate Intermittent Explosive Disorder, mIED). The MMN reflects automatic change detection, whereas the P3a reflects involuntary attentional mechanisms. Both MMN and P3a can be elicited in the absence of attention. Results showed that the P3a was significantly smaller in the mIED group compared to the control group, whereas neither MMN nor P3b differed between groups. These data provide the first ERP correlates of mIED, showing that mIED affects cognitive mechanisms of involuntary control of attention (as reflected in the P3a). Because the P3a receives main contributions from the frontal, and the MMN from the temporal lobe, results support the notion that increased impulsivity is related to frontal, rather than temporal lobe function.