The Neural Mechanism Of Proportion Congruent Effect In Interference Control

Cognitive control,also called executive function or executive control,is a key function of human brain.It refers to a family of top-down mental process needed when you have to concentrate and play attention,when going on automatic or relying on instinct or intuition would be ill-advised,insufficient,or impossible.Cognitive control could help people making behavior plan,leading goal-directed behavior,adapting complex environment.There is general agreement that there are three core components of cognitive control: inhibitory control,working memory and cognitive flexibility.Interference control,which is belong to inhibitory control,is refer to how the cognitive control system resolve the confliction when the other unrelated information inferenced the task goal.Studying confliction control has a great help for us to understand the way of cognitive control act.Stroop task is the most commonly used to study interference control.Stroop effect,which means the difference of reaction time of congruent and incongruent,is used by many investors to represent the power of interference control.In the field of studying inference control,proportion congruent(PC)effect and confliction adaption are frequently focused by researchers.Confliction adaptation,which is refer to that the Stroop effect could be decreased after incongruent than congruent,reflects how cognitive control system use the experienced confliction to resolve the coming confliction.Proportion congruent effect,which is refer to that the size of effect could rise up with increase proportion of congruent trials,reflects how cognitive control flexible modulates strategies dependent various task contexts.In fact,proportion congruent effect and confliction adaption reflect two different aspects of cognitive control: the former reflects how cognitive control rapid adjust in a short time scale after experienced confliction;the later reflects how cognitive control slow modulate in a long time scale according to different task contexts.The surveys of cognitive control has further developed during the past decades.Most studies are explore the neural mechanism of confliction adaptation and conflict monitoring account is accepted by many researchers.According to this account,there is a special system which named as confliction monitoring system existed in human brain.It constitute of two modules: monitoring module,which the core brain area is anterior cingulate cortex(ACC),is response for monitoring when the confliction coming;confliction resolving module,which the key brain area is doraslateral prefrontal cortex(dlPFC),is response for receiving information coming for ACC and conflict resolving.On the contrary,PC effect has not deeply explored by researchers and most studies of PC effect are behavior researches.PC effect has two different types according to object the proportion work on: list-wide proportion congruent(LWPC)effect and the item-specific proportion congruent(ISPC)effect.Studies show,LWPC is a more lasting effect and ISPC is more salience,because there could only observe ISPC if ISPC and LWPC co-exist.There is a fierce controversy about the theory of PC on account of deficiency of behavior study and lack evidences of neural basis.The theme of controversy is whether PC based on the cognitive control or stimulus-response association.Cognitive accounts,include the dual cognitive mechanism,confliction monitoring hypothesis,the dual mechanisms of control framework,stated that cognitive control plays an important role in PC.Non-cognitive accounts,include contingency learning and temporal learning hypothesis,emphasis on stimulus-response association.Lacking survey of neural mechanism on PC,the mainly purpose of this paper is explore the neural mechanism of PC.Study one,use the traditional LWPC paradigm and collect the fmri data,find out the brain areas related with PC.After that,analysis the BLOD signal of these areas to explore the functions.On basis of the results,study two use the brain network analysis to calculate the effective connectivity among those brain areas.Exploring cognitive control system how to adjust their control strategies according to various task background from the hierarchical organization of brain network.The study one replicated the behavior results of PC.High proportion of congruent speeds the reaction times of congruent and shows down the RT of incongruent;high proportion of incongruent speeds the RT of incongruent and shows down the RT of congruent.The analysis of fMRI data shows there are nine brain areas,which are fusiform gyrus,anterior prefrontal cortex,dorsolateral perfrontal cortex,superior parietal lobule,inferior parietal lobule,ACC,supplementary motor areas,insula,right inferior frontal gyrus,related with PC.Based on the BLOD signal pattern,these brain areas could divide into two system: sensitive to confliction system,which includes FFA,aPFC,IPL,ACC and rIFG;sensitive to proportion system,which includes insula,SPL,dlPFC,and SMA.CMS mainly process the time feature of confliction and CRS mainly process the quantity character of confliction.Based on the results of study one,we used brain-network analysis method to explore what's the mechanism underlying cognitive control system adjust their strategies dependent on various task background,which through the organization of brain network displayed by hierarchical layout.At first,we conducted a traditional psychophysiological interaction analysis based on 9 ROIs and used a new method named as multiregional PPI to calculate effective connectivity(EC)between each ROI.We used the strength of EC to define brain network at single subject level and group level.We also used the average connectivity strength(ACS)and globe efficiency(GE)to represent the power of function of networks.Both for ACS and GE,they are linear increase with proportion.The result of hierarchical layout of brain network shows,cognitive control system executes completely different strategies under various environment.In the MI block,dlPFC always plays a role as commander of entire network because it located in the top of network both for congruent and incongruent.However,it executed an order through different ways.For the congruent network,IPL and FFA lay in the bottom;for the incongruent network,rIFG and FFA lay in the bottom.In the neutral block,FFA and SMA always lay in the bottom means control strategy is intense stimulus process and responses.Whereas,the commander of control is different for congruent and incongruent.Because aPFC,insula and dlPFC located in the top at the same time for congruent network,but only dlPFC lays in the top for incongruent.In the MC block,aPFC located in the top,SMA and rIFG lay in the bottom for congruent;insula located in the top,IPL and FFA lay in the bottom for incongruent.We speculated that control strategies could have different impact on different trail types.In the MI block,control strategy,which is configured based on confliction resolution,is mainly work on incongruent trials and speed the responses,however this strategy may harm the responses of congruent trials.Similarity,in the MC block,control strategy,which is configured based on fast response,is work on congruent trials and speed the response and harm the response of incongruent trials.The significance of this paper is to provide more evidences for PC from neural basis and explore the neural mechanism of PC from a new perspective.We discussed the neural mechanism from the function of brain areas and the hierarchical organization of brain network,we speculated diversity of cognitive control strategies impact on congruent and incongruent is the primary cause of PC.Our results support the cognitive account of PC and may promote the development of account of PC.