Multiple Conflicts-driven Control Mechanisms In The Multi-source Interference Task(MSIT)

In daily lives,humans are often confronted with complicated situations,in which large amounts of information inputs would compete for attention resources and therefore elicit conflicts in information processing.To optimize behavior performance,cognitive control is engage to resolve conflicts and guide goal-directed behavior.Cognitive control refers to the ability to flexible adjust attention,thoughts and behaviors in accordance with internal goal.To better understand the mechanisms subserving cognitive control,conflict tasks such as the Stroop task,the Flanker task and the Simon task were generally applied.In early studies,conflict monitoring theory was mainly used to explain the mechanisms of cognitive control.According to the conflict monitoring theory,conflict control is domain general.While,later studies have found that conflict control is domain specific and there are multiple control loops in the brain that can involve in resolving different type of conflict in a parallel way.Whether conflict monitoring theory or multiple conflicts control theory,the main concern is the control mechanism of single type of conflict.However,in daily lives,we often confronted with complicated situations,in which multiple conflicts would compete for limited attention and hamper the execution of behavior.While existing studies failed to provide information regarding how multiple conflicts-driven control achieved.Due to lack of studies concerning multiple conflicts control,the current study aimed to investigate multiple conflicts-driven control mechanisms from the level of behavioral and neuroimaging.On the basis of the MIST task,the study 1 sought to investigate the mechanisms subserving multiple conflicts control through cognitive training.In previous studies,cognitive training was supposed to be a useful tool in uncovering the mechanisms associated with conflict control.Since cognitive training can decompose different processes of the conflict task and reveal the dynamic changes of these processes.We decided to investigate the underlying mechanisms of multi-conflicts control by comparing training induced changes in multiple conflicts and its subcomponents.Whilst,study 2 aimed at figuring out the neural substrates underlying multiple conflicts control with the employment of functional magnetic resonance imaging(f MRI).Firstly,by a whole brain analysis,we aimed to found those regions involved in multiple conflicts control,and regions show more activation under response conflict or stimulus conflict when compared to congruent.Secondly,we conducted a conjunction analysis to find those brains regions,which show overlap activation under multi-source interference and response interference/stimulus interference.By this analysis,we are able to clarify the relative contributions of different cognitive interference to multi-conflict control.There are two experiments in the study 1.In experiment 1,we found significantly reduced conflict effect in the training group compares to the active control group after 5 days training.This indicating that training could improve the ability to deal with multiple conflicts.Based on the experiment 1,the experiment 2 further decomposed cognitive interferences of the multi-source interference in the MSIT task to examine the effect of training on multi-source interference and its subcomponents.After a certain period of training,we observed significantly reduced multi-source interference and response interference in the training group,while stimulus interference keep stable.In the active control and the passive control group,no training related effect observed.In the training group,the decreases of response interference was due to training induced enhancement in suppressing the processing of task irrelevant information.While the stimulus interference remains stable,indicating that the incompatibility between task relevant and irrelevant stimulus features may be intrinsic.Based on these results,the study 1 illustrated that: 1)cognitive training can optimize the ability the resolve multiple conflicts;2)after training,the reduction of the multi-source interference is due to the elimination of the response interference,indicated that the ability to suppress the processing of task irrelevant information is important in resolving multiple conflicts;3)after training,the persistence of multi-source interference is attribute to the robust stimulus interference.The study 2 aimed to investigate the neural substrates underlying multiple conflict-driven control by the experiment 3.Firstly,by a whole brain activation analysis,the experiment 3 found that the dorsolateral prefrontal cortex(DLPFC),middle frontal gyrus(MFG),inferior frontal gyrus(IFG),superior parietal lobule(SPL),inferior parietal lobule(IPL),supplementary motor area(SMA)and inferior occipital gyrus(IOG)et al.,show more activation under multi-source conflicts condition when compared to congruent condition.Based on the role of aforementioned brain regions in cognitive control,the results of the experiment 3 indicated that in the MSIT task,successful conflict resolution correlated with enhanced processing of task relevant information through top down attention control of the DLPFC on the occipital gyrus.Meanwhile,the modulation of the IFG on motor cortex indicated that inhibition of task irrelevant information also played important role in multi-source conflicts control.Secondly,by a conjunction analysis,we sought to find those regions,which show overlap activation in multi-source conflicts and response interference/stimulus interference condition.Then neural activities(Beta value)of those regions under the condition of response interference/stimulus interference were obtained.By a regression analysis,the current study found that those regions show overlap activation under multi-source conflict and stimulus conflict,whose neural activities under stimulus interference condition could predicate behavioral multi-source conflicts effect(R2=0.68,p<0.05).On the basis of above results,the study 2 shows that: 1)multiple conflicts control is achieved through enhancing the processing of task relevant information and suppressing the processing of task irrelevant;2)the resolution of stimulus interference share more neural mechanisms with the resolution of multi-source interference,which indicated that the stimulus interference is the key component of multi-source interference.The significance of this paper is to provide evidences regarding the resolution of multiple conflicts from behavioral and neural basis.The findings of the study 1 and the study 2 indicated that multiple conflicts-driven control correlated with enhancing the processing of task relevant information and suppressing the processing of the irrelevant information.Both conflict specific control mechanisms were involved,but the ability to inhibit task irrelevant information may be more flexible,which can quickly decline with training.Besides,the results of the study 1 and the study consistently showed that multi-source interference mainly steaming from stimulus interference,which are more stable and less affected by training.