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Investigating Brain Mechanisms Of Salient Distractor Suppression Using FMRI

Posted on:2024-05-13Degree:MasterType:Thesis
Country:ChinaCandidate:F LinFull Text:PDF
GTID:2544307079474264Subject:Electronic information
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Faced with various kinds of complicated information in life,people need to filter the information irrelevant to the goal and select the information related to the goal,that is,they need selective attention to choose information.The ability to suppress or ignore irrelevant information refers to distractor suppression,which is crucial for goal-directed behavior.Distractor information with significant physical characteristics is typical of target irrelevant information,and the brain’s inhibition mechanism is still unclear.This study intends to explore the brain mechanism of salient distractor suppression based on functional magnetic resonance imaging.To this end,in this study,the distractor suppression ability was measured by the interference suppression test and the Cognitive Failures Questionnaire,and the task state,resting state and structural image magnetic resonance brain imaging data of the interference suppression experiment were collected.In the distractor suppression experiment,specific color item served as a significant distractor to induce the distractor suppression mechanism.The subjects were required to perform the task of identifying the target when there were significant distractors and no significant distractors.The analysis of brain imaging data mainly focused on the brain activation and brain connections in the task state,and the resting state functional network related to the ability of individual interference suppression.The behavioral results of the distractor suppression experiment showed that the response time was faster in the presence of significant distractor than in the absence of significant distractor,indicating that significant distractor successfully induced distractor suppression.Therefore,the difference between the reaction times of the two conditions in the experiment was used as one of the behavioral indicators of the individual’s interference suppression ability,and the score of the disturbance item in the scale was used as another behavioral index of the individual’s interference suppression ability.Task state brain activation analysis showed that the bilateral precentral gyrus and left superior frontal gyrus were significantly activated when searching for the target.These activated brain areas were selected as the area of interest for further analysis.This study found that the blood oxygen level-dependent signal change rate of the bilateral superior frontal gyrus and bilateral parietal inferior gyrus was lower with a salient distractor than without a salient distractor.Further analysis found that the rate of blood oxygen level-dependent signal change in the right middle occipital gyrus was significantly correlated with the response time when there were significant interferents,and the difference between the gray matter volume and the response time was significantly correlated.Results of psychophysiological interaction analyzes showed that functional connectivity from the left parietal to right frontal cortex was significantly associated with the difference in reaction times.The predictive model analysis based on the connectome found that the whole brain connectivity based on the task state or the resting state could not predict the difference in reaction time,but the whole brain connectivity in the resting state could predict the disturbance item score of the scale.Further analysis using the sub-network to predict the interference suppression ability found that the prediction model built mainly on the connection between the frontoparietal network,the motor network and the visual I area can also predict the score of the interference item of the scale.These results suggest that the function and structure of brain regions within the frontoparietal network,the motor network,and the vision-related network are related to disturbance suppression,and that global functional integration within and between these networks plays a role in the process of significant disturbance suppression.In summary,this study provides evidence for the feasibility of feature-based interference suppression and reveals the brain activation and brain-wide functional network basis of interference suppression.
Keywords/Search Tags:Task irrelevant salient distractor, Distractor suppression, Task-based fMRI, Resting state functional network
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