An ERP Study On The Characteristic Of Inhibition Control On Impulsivity

Inhibition control has been the focus of many researchers,and it is perhaps most often found among patients whose disorder is characterized by impulsivity.While,reports on impulsivity within the normal population do not consistently indicate a deficit in inhibition control.The dual mechanisms of control(DMC theory)account posited two qualitatively different cognitive control mechanisms.Proactive control is a sustained and capacity-demanding mechanism that is used to prevent interference,whereas reactive control acts transiently,poststimulus onset,to resolve interference.The inconsistent results on whether high impulsivity is associated with impairment in inhibition control in the general population might be because different forms of control strategy were used in the specific tasks.However,few studies have examined the proactive and reactive inhibition control respective on response inhibition and interference inhibition with self-reported impulsivity in healthy individuals,and the purpose of this study was to fill that gap.To explore the influence of self-reported impulsivity,participants with high and low impulsivity(HI and LI,respectively)performed a modified version of the paradigm stop-signal task and the prime-target interference task while event-related potentials(ERPs)were recorded.The stop-signal tasks,which are often used to investigate response inhibition,was designed so that the extent of the preparation.Specifically,in addition to the conventional go trials where preparation to stop was required(“uncertain-go” trials),another type of go trial was introduced where a stop-signal was never given and such preparation was unnecessary(“certain-go”trials).The results showed:1.The preparation cost(calculated by subtracting the reaction times in the certain-go trials from those in the uncertain-go trials)showed significant negative correlation with SSRT(a common index used to evaluate the efficiency of response inhibition)suggests that greater preparation supports more efficient inhibition.In addition,the preparation cost showed marginality significant negative correlation with SSRT in HI group but not in LI group.Thats may suggests greater preparation supports more efficient inhibition for HI group.2.For the proactive control,there was a larger N2(FCz and Cz),P3 and LNC(Fz)for uncertain-respond trial relative uncertain-respond trial in HI(High impulsive)group,but not in LI(Low impulsive)group,showing that the proactive effect was significant for HI group but disappeared in LI group.Thus,the effect on N2,P3 and LNC for the HI group might indicate that such individuals must recruit compensatory control resources to resolve interference.3.For the reactive control,the behavioral data revealed significant longer SSRT in HI group than in LI group;the three ERP indexes(N2,P3 and LNC)for stop-signal trials showed significant larger in HI group than in LI group.This rusults.suggests that greater preparation supports more efficient inhibition in HI group.The first study suggests that high levels of impulsivity might be more recruiting proactive control for sustained active maintenance of response inhibition task goals.But the results on HI group suggest preparation makes a complementary contribution to response inhibition during performance of a stop-signal task compare to the LI group.We manipulated the proportion of congruent trials to distinguish between proactiv(high proportion of interference trials)and reactive control(low proportion of interference trials)in the prime-target interference task.The results showed:1.In the mostly congruent context(reactive control),the interference effect on the MFN and the N-SP was greater and the effect on the P-SP was lower in the HI compared to the LI group.2.The three ERP indexes(MFN,P-SP,and N-SP)of interference processing in the mostly incongruent context(proactive control)were insensitive to variations in impulsivity.The second study suggests that high levels of impulsivity might be associated with reduced efficiency of processes supporting reactive cognitive control to resolve interference when interference is not expected.In contrast,the results suggests that HI individuals were as effective as LI individuals in recruiting proactive control for sustained active maintenance of task goals to enable optimal cognitive performance throughout the experimental blocks where interference occurs frequently.In conclusion,these results indicate that impulsivity has a negative influence on reactive,but not proactive,cognitive control.In conclusion,the results showed that impulsivity has a different influence on the response inhibition under different control type and interference effect under different task contexts.For the response control,the results on HI group suggest preparation makes a complementary contribution to response inhibition during performance of astop-signal task compare to the LI group.For the inhibition control,the results indicate that impulsivity has a negative influence on reactive,but not proactive,cognitive control.