| Attention-deficit hyperactivity disorder(ADHD)is a neurodevelopmental disorder known as hyperactivity disorder.Attention deficit,hyperactivity and impulsivity are the core symptoms of ADHD.Resting-state functional magnetic resonance imaging is a well-established technique that has been widely used in ADHD research,but the construction of fine brain atlases based on magnetic resonance imaging and its application in ADHD are less studied.In this paper,we focus on the precuneus brain region,which is related to higher cognitive functions,and construct a precuneus subregion atlas based on restingstate functional MRI phase synchronization,analyze the phase synchronization between precuneus subregion and whole brain regions,its complexity and Granger causality characteristics,and apply it to ADHD symptom assessment and brain mechanism research to verify the application value of precuneus subregion atlas.The main research components are as follows:The first part is a study on the construction of a sub-regional atlas of the precuneus based on restingstate functional magnetic resonance phase-synchronous functional connectivity.The lack of precise brain atlases has greatly limited the in-depth study of brain diseases.In order to improve this situation,the present study finely delineated precuneus brain regions based on resting-state functional magnetic resonance phase synchronization features,and constructed a precuneus subregion atlas to analyse the subregions and brain regions that were significantly differentially connected in ADHD and healthy controls.The results showed that the subregions of difference in ADHD patients were mainly concentrated in subregion 10 of the left precuneus and subregion 2 of the right precuneus.The differences were mainly in the left cingulate gyrus,the right posterior cingulate gyrus,the right inferior parietal gyrus,the bilateral inferior frontal gyrus triangle,and the bilateral parabasal gyrus.The results suggest that it is feasible to construct a subregional map of the precuneus based on resting-state MRI phase-synchronous functional connectivity,and provide supporting information for the study of brain mechanisms of ADHD.The second part of the study is a review of clinical indicators of ADHD based on phase synchronization and its complex functional connectivity in the precuneus subregion atlas.Most existing studies have constructed resting-state functional brain networks based on linear correlation coefficients,and it is a challenge to characterise the non-linear properties of brain networks.In this study,we developed a prediction model for ADHD clinical indicators based on phase synchronization of precuneus subregion mapping and phase synchronization complexity characterization based on low-frequency amplitude and detrended fluctuation analysis,respectively,and analyzed the association between precuneus subregion and brain region functional connectivity and ADHD clinical indicators.The results showed that the whole-brain functional connectivity network based on phase synchronization of right precuneus subregions was more correlated with ADHD symptoms and the model predicted better.The main brain regions with differences were temporal pole,cingulate gyrus,middle orbitofrontal gyrus,parahippocampal gyrus,frontal pole,transverse temporal cortex and middle temporal gyrus,and the main subregions with differences were subregions 1,2 and 5 of the left precuneus and subregions 3,8 and 10 of the right precuneus.The whole-brain functional connectivity network constructed based on the detrended fluctuation analysis of phase synchronization complexity of the right precuneus subregion mapping was more correlated with the mixed symptom index and the model predicted better.The discrepant brain regions were mainly temporal pole,superior frontal gyrus,middle orbitofrontal gyrus,syrinx,lingual gyrus,parahippocampal gyrus and paracentral lobule,and the discrepant subregions were mainly subregions 1,3 and 6 of the left precuneus and subregions 2,8,9 and 11 of the right precuneus.For indicators of attention deficit symptoms,the model did not predict well.The present study reveals the brain mechanisms of precuneus subregions and brain regions associated with clinical indicators of ADHD,providing an auxiliary method for the assessment of clinical indicators of ADHD.The third part is the application of Granger causal analysis effector connectivity based on precuneus subregion mapping in ADHD research.A growing number of studies have shown the direction of information flow between nodes of functional brain networks,which is important for revealing the functional mechanisms of brain disorders.The present study used Granger causal analysis of information flow direction differences between the precuneus subregions in ADHD and healthy controls based on precuneus subregion mapping.The results of the study showed that the causal connections between the left precuneus subregion 8 and other subregions were significant in ADHD,and the causal connections between the right precuneus subregions 4,6 and 8 and other subregions were significant in ADHD.This study reveals the abnormal connectivity mechanism of the causal connectivity network in precuneus subregions of ADHD patients and further validates the application of precuneus subregion mapping.This study focused on the construction of precuneus subregion atlases based on resting-state functional magnetic resonance phase synchronization,and the study of ADHD clinical indicators and brain network mechanisms.The main abnormal precuneus subregions and brain regions of ADHD patients were identified,functional connectivity features with high correlation with ADHD clinical indicators were uncovered,and the information flow network among precuneus subregions of ADHD patients was revealed.This paper constructs brain connections and brain networks associated with precuneus subregions,providing a new perspective for the development of ADHD clinical indicators assessment models and revealing ADHD-related brain mechanisms. |
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