The role of trait impulsivity in response inhibition: Event-related potentials in a stop-signal task

• Relation between impulsivity and inhibition in normal adults was investigated.
• No significant group differences were shown on overt behavioral performance measures.
• P3 amplitude is significantly smaller in the high impulsive participants.
• The high impulsive group seems less efficient of inhibitory control.
• Impulsivity might have a potential influence on inhibition as reflected in ERP.

The study examined the relation between self-reported impulsivity and inhibitory control in normal individuals. We compared stopping performance and neural correlates of stopping on stop-signal task between participants who scored in the top (n = 12) and bottom 25% (n = 12) on Impulsivity Scale from a sample of 305 male adults. Participants scoring high on impulsivity did not show impaired inhibitory control. However, it seems that the high impulsive tended to make more errors of commission and omission. Enhanced N1 amplitudes were found in successful than failed inhibition trials. The high impulsive group had smaller P3 amplitude than the low impulsive group. It appears that the high impulsive group may have a less efficient inhibitory control. Impulsivity Scale non-planning impulsiveness score and inattention score of Adult ADHD Self-Report Scale (ASRS) were negatively correlated with P3 amplitudes on successful inhibition trails, suggesting that impulsivity could have the potential influence on inhibitory control.