The Difference Between Task-setting Inertia And Task-setting Reconstruction Based On Morphological And Resting-state Functional Connectivity

Cognitive flexibility plays a large role in our daily life,which often requires us to perform multiple tasks at the same time,requiring us to plan and schedule "switching" from one task to another until all tasks are completed.The task switching paradigm is an important paradigm for measuring cognitive flexibility.In the task switching paradigm,the current task is divided into two conditions,task switching and task repetition,according to whether the current task is the same as the previous task,and the difference in response between these two conditions is called switching cost(SC).It is believed that the switching cost mainly comes from Task Setting Reconstruction(TSR)and Task Setting Inertia(TSI),and the cue target interval mainly affects TSR,but there is a lack of research on the involvement of TSR and TSI in the switching cost and their neural mechanisms in the brain.However,there is a lack of research on the involvement of TSR and TSI in switching costs and their differences in neural mechanisms in the brain.Therefore,the purpose of this study was to investigate the relationship between TSR and TSI and switching cost and their differences in morphological and resting functional connectivity.Three studies were conducted with these purposes in mind: StudyⅠ added a rest cue to the general task cue switching paradigm and found behavioral indicators of task-set reconstruction and task-set inertia by comparing differences between the conditions of switching between two tasks,switching from rest to task,and task repetition through a reaction-time technique.For the analysis of magnetic resonance morphology and resting functional connectivity,the voxel-based morphological analysis method,the cortical processing-based structural network and the graph-theoretic analysis method of resting functional network were used to explore the brain nodes and network indicators related to the switching cost;Study II combined the behavior related to task switching in the public database with the magnetic resonance structural image and resting functional image data for validation.Study III targeted the prefrontal brain regions associated with switching cost and used the continuous theta stimulation(c TBS)technique in transcranial magnetic stimulation to intervene in the left middle frontal gyrus to explore the effects of task switching in the left middle frontal gyrus from a neuromodulation perspective.In summary,this thesis reveals the neural mechanisms associated with the total switching cost and its main components task-setting reconstruction,task-setting inertia,from voxelbased and cortical-based analysis methods using magnetic resonance morphology and resting functional images.On behavioral analysis,Study I and Study III found that total SC was equal to the sum of task-set reconstruction and task-set inertia,and Study II and Study III found that cue-target interval affected switching cost by influencing task-set reconstruction.On the analysis based on morphological and resting functional connectivity,Study I and Study III repeatedly verified the correlation between left middle frontal gyrus gray matter volume and switching cost in the voxel-based morphological analysis.In the c TBS study,by comparing the behavioral performance of target and control sites on task-setting reconstruction and task-setting inertia,c TBS was found to have a significant effect on task-setting reconstruction,but no effect on task-setting inertia.This thesis reveals the behavioral and neural mechanisms related to total switching cost and its main components,i.e.,task-setting reconstruction and task-setting inertia,from behavioral,morphological and resting functional connectivity,which theoretically complements and validates the research on the sources of switching cost,and methodologically applies voxel-based morphological analysis methods and graph theory to the research on switching cost,which is important for the research on neural mechanisms related to task switching and cognitive flexibility.