Neural correlates of stopping and self-reported impulsivity.

OBJECTIVE To examine the relation between self-reported impulsivity, inhibitory control, and the neural correlates of stopping performance within the normal population. METHODS Healthy individuals scoring high and low on trait impulsivity performed an auditory stop-signal task. Stopping performance and neural correlates of stopping (i.e. N1 and stop P3) were compared between the impulsive groups as well as between participants who were slow and fast in stopping. RESULTS As expected, N1 and stop P3 were larger for successful relative to failed stops (i.e. N1 and stop P3 effects). Participants scoring high relative to low on impulsivity showed equal stopping performance, had larger stop P3, but similar N1 effects. Slow as compared to fast stoppers had reduced stop P3, but similar N1 effects. CONCLUSIONS Participants scoring high relative to low on impulsivity may need more effortful inhibitory control to yield equal stopping performance. Slow relative to fast stoppers may have weaker inhibition processes and abnormal error processing. In contrast to ADHD, both high impulsives as well as slow stoppers had an intact N1 effect. SIGNIFICANCE Subjective impulsivity and slow stopping in healthy individuals cannot be generalized to ADHD.