The Neural Mechanism Of Conflict Control In Numerical Task And Semantic Task

Event-related brain potentials (ERPs) are special elicited brain potentials which are produced through endowing stimuli with peculiar psychological meanings and utilizing multi-stimuli. The elicited brain potentials, reflecting the neural electrophysiological changes of the brains, are recorded on the scalp through the average overlapped skills. ERP is closely related to human cognitive processes and is adopted widely in the researches about the brain mechanism. There are investigative and applied values of ERPs, known as the observational window of the brain function, in psychology, physiology, cognitive science, neural science, clinical physic and other pertinent life sciences. Conflict control is one of the most concentrated issues in cognitive psychology. The opinions on the stages from which the control originated are not consistent in the recent researches. In addition, few studies have focused on the similarities and differences that involve semantic and numerical conflict control.This research consists of two experiments. First of all, in Experiment 1, using counting Stroop paradigm, the neural mechanism of conflict control in numerical task was investigated by ERPs. Behavioral data showed that the task yielded a robust interference effect as indexed by a longer reaction time for the number incongruent condition. Scalp event-related potential analysis revealed a greater negative difference in N2 and a late positive component (LPC) in the number incongruent compared with the number congruent condition. Dipole analysis of the difference wave (number incongruent minus number congruent) localized the generator of the N2 to the anterior cingulate cortex, which might be related to conflict monitoring in the primitive phase of cognitive processing, whereas LPC embodies conflict resolution in the terminal stage. Then, in Experiment 2, a modified Stroop task was utilized to investigate the neural mechanism of conflict control in a deep semantic processing task. The results revealed that the meaning incongruent condition elicited more negative event-related potential deflections N300 and N520, than the meaning congruent condition, which provide evidence for the dissociation of neural circuits between conflict monitoring and conflict resolution in the processing of conflict control. Dipole analysis of the difference wave (meaning incongruent minus meaning congruent) localized the generator of the N300 to the posterior cingulate cortex, which might be related to the inhibition and monitoring of the unrelated interference attribute in the early phase of cognitive processing.The results were as follows: There are two cognitive phases during conflict control in numerical task and semantic task in the Chinese symbol system.Conflict monitoring is associated with the primitive stage, and conflict resolution is related to the terminal stage. The representation of conflict monitoring is similar in two tasks, a negative different wave (incongruent minus congruent). However, the representations of conflict resolution are varying according to the types of tasks. The negative difference waves (incongruent minus congruent) are a token of conflict control.The cingulate cortex of limbic system has a close link with conflict monitoring.