The Neural Mechanisms Of Flanker Conflict,Congrugence And Distraction Effects:an Event-related Potential Study

ObjectiveThe spatiotemporal pattern of ERP was used to investigate flanker task and reveal the neural mechanisms of its conflict effect,congrugence effect and distraction effect.MethodsTwenty college or graduate students(50%female)completed the flanker task,which included four levels:incongruent(INC),congrugent(CON),neutral(NEU)and target-only(TAR).The reaction time,accuracy and 19-channel ERP were recorded.Both behavioral data and ERP data were submitted to two-way ANOVA of repeated measurement:2(task relevance of flanker:yes(incongruent,congruent),no(neutral,singleton)*2(distraction:high(incongruent,neutral),low(congruent,singleton))and two-tailed paired t-test.The F-values and t-values of the 19-channel ERP were interpolated to obtain the statistical parametric mapping(SPM)using the analysis software of ERP system.ResultsThe interaction effects of reaction time and accuracy were significant respectively:F(1,19)=42.907,P=0.000,partial=0.693;F(1,19)=30.604,P=0.000,partial=0.617.The conflict effects of reaction time was significant:INC(413.66±3 1.22 ms)vs.NEU(396.92±29.35 ms);t(19)=8.133,P=0.000,d=1.865.Its ERP effects included the occipital N1(200-240 ms),frontal-parietal-occipital N2b(320-400 ms)and fronto-central P3b(500-660 ms).The conflict and congrugence effects(INC-CON)of reaction time was also significant:CON(391.78±28.12 ms)vs.INC(413.66±31.22 ms),t(19)=11.75,P=0.000,d=2.695.Its ERP effects included in the left frontal P2(200-260 ms),the frontal-parietal-occipital N2b(340-400 ms),and the frontoparietal P3b(480-560 ms).The congrugence effect of response time was significant:CON(391.78±28.12 ms)vs.NEU(396.92±29.35 ms),t(19)=3,566,P=0.002,d=0.818.Its ERP effects included the medial frontal P2(160-200 ms)and the occipitoparietal N1(200-220 ms).The distraction effect of reaction time significant:NEU(396.92±29.35 ms)vs.TAR(388.30±28.43 ms),t(19)=5.613,P=0.000,d=1.287.Its ERP effects included the medial and right frontal P2(200-240 ms),occipital N1(180-200 ms)and distractor positivity(Pd)(260-360 ms).ConclusionOur results showed that the congrugence effect and distraction effect are mainly reflected by the frontal P2,which may engage the top-down regulation to the posterior brain region.The occipitoparietal N1 involved discrimination of task-relevent and task-irrelevant information and the occipital Pd involved active inhibition of distraction information.The conflict effect mainly appeared in the second stage:the frontocentral N2b reflected conflict evaluation and its dominant distribution in the right hemisphere suggested its involvement of response inhibition.