The Abnormal Brain Network Properties In Patients With Acute Stress Response After Traffic Accident

Part One Functional connectivity density mapping in patients with acute stress response by using resting-state functional MRI after traffic accidentObjective:To explore the changes of brain activity in traffic accident survivors with acute stress response within a week by using functional connectivity density(FCD)method.Methods:We collected twenty traffic accidents survivors with acute stress disorders(Acute Stress Disorder Interview>3)and twenty healthy controls from Nanjing Jinling hospital and performed the 3T resting-state functional magnetic resonance imaging scan.Functional connectivity density mapping was used to compare the brain functional connective networks between acute stress response survivors and controls.In additional,Pearson correlation was performed between abnormal short,long-range FCD values and clinical indices.Results:Compared with controls,patients with acute stress response showed decreased short-range FCD in left ventromedial prefrontal cortex,left hippocampal and parahippocampal gyri,and increased short-range FCD in right precentral gyrus,left inferior parietal and superior parietal lobes.Compared with normal controls,ASR patients showed increased long-range FCD in left precuneus.The HAMA score of patients positively correlated with short-range FCD value of the left vmPFC.Conclusion:The long-and short-range functional connectivity in frontal-limbic system is widely changed in survivors with acute stress response,especially the short-range FCD change more significantly,and partly correlated with the severity of their stress symptoms.Part Two Mapping effective connectivity in functional brain networks of acute stress disorder patients after traffic accident based on dynamic causal modeling analysisObjective:To explore the changes of extrinsic and intrinsic effective connectivity in three major resting-state functional brain networks of traffic accident survivors with acute stress response by using dynamic causal modeling analysis.Methods:We collected twenty traffic accidents survivors with acute stress disorders and twenty healthy controls and performed the 3T resting-state functional magnetic resonance imaging scan.The Independent component analysis was used to extract the main brain regions of three major functional brain networks—default mode network,salience network and executive control network.Then we conducted the dynamic causal modeling analysis with the SPM12 to explore the extrinsic and intrinsic effective connectivity in the three networks.Statistical analyses were also performed to evaluate the inter-group differences of effective connectivity.In additional,correlation analysis was performed between the effective connectivity strength of brain regions with significant differences in two groups and clinical indices.Results:Compared with controls,patients with acute stress response had less robust extrinsic and intrinsic effective connectivity in three major functional brain networks.ASR patients showed significant decreased effective strength from right dorsolateral prefrontal cortex to left posterior parietal cortex.And the HAMA score of subjects negatively correlated with the mean effective connectivity strength.Conclusion:The extrinsic and intrinsic effective connectivity in three major functional brain networks is widely changed in survivors with acute stress response,especially the effective connectivity from dorsolateral prefrontal cortex to posterior parietal cortex within executive control network change more significantly.And these changes may be associated with their anxiety status.Part Three Topology of the brain structural network in patients with acute stress response after traffic accidentObjective:To explore the changes of brain activities in traffic accident survivors with acute stress response(ASR)within a week by using complex networks analysis method based on graph-theory,and to find out the alteration of topological properties in structural brain network.Methods:Seventeen traffic accidents survivors with acute stress disorders(Acute Stress Disorder Interview,ASDI>3)and eighteen healthy controls underwent the 3T diffusion tensor imaging(DTI)magnetic resonance imaging scan.The graph-theory analysis method was used to compare the characteristics structural brain network properties and nodal features between ASR survivors and controls.Statistical analyses were also performed by including anxiety and depression as covariates to evaluate their effects.In additional,Pearson correlation was performed between abnormal parametric values and clinical indices.Results:The brain structural networks had small-world properties in both groups(P=0.941).While compared with healthy controls,patients with acute stress response showed increased weighted connectivity strength(Si),nodal betweenness centrality(BCi)in left triangular part of inferior frontal(IFG triang_L)and increased Si in orbital part of inferior frontal gyrus,as well as showed obviously decreased Si in left caudate.Furthermore,the inclusion of anxiety and depression as covariates abolished nodal parameters differences in brain areas with decrease and increased Si in IFG triang_L.Conclusion:The brain structure network in ASR patients has small world properties.But nodal parameters changed obviously in some nodes compared with healthy controls and mainly located in prefrontal lobe and striatum.High levels of anxiety and depression in ASR patients may partly account for these alterations.