Abnormal Brain Functional Activity In Patients With Generalized Anxiety Disorder

Generalized anxiety disorder(GAD)are mainly characterized by persistent nervousness and anxiety,accompanied by some clinical features such as nervous function excitement and excessive alertness.Previous researchers have investigated the physiological and psychological mechanisms of GAD from multiple levels,but the pathological mechanism of GAD is still unclear.The research is mainly from the dynamic point of view,first,we studied the dynamic changes of the brain’s spontaneous functional activities in resting state;second,we analyzed the regulatory relationship of brain-related brain regions in superior illusion tasks to characterize the dynamic characteristics of brain function activity in GAD.This article mainly includes the following two parts:1.At present,there is still a lack of dynamic research on the local brain activity of GAD.This study used the amplitude of low frequency fluctuation(ALFF)method combined with the sliding window analysis method to study the temporal variability of local brain activity in patients with GAD.The results showed that patients with GAD exhibited increased dynamic ALFF variability in the bilateral dorsomedial prefrontal cortex,hippocampus,thalamus and striatum,the left orbital frontal gyrus,inferior parietal lobule,temporal pole,inferior temporal gyrus,and fusiform gyrus.These regions were mainly associated with basic emotion,cognition and advanced social emotional processing.The abnormal dALFF variability of the striatum was positively correlated with the anxiety severity of GAD.Theses findings suggest that local brain activity was altered in patients with GAD over time,and these abnormal areas may be correlated with emotion dysregulations and cognitive deficits of GAD.This study provided important insight into understanding the neuropathological mechanism of GAD from the view of dynamic local brain activity.2.Negative self-schema is an important cognitive model feature of GAD.In this study,we used the superiority illusion paradigm(SI)to study the relationship between self-schema and social function impairment of GAD,and then used the dynamic causal model to analyze the effective connections between key brain regions.Behavioral results showed that GAD has lower SI scores,especially,the significant differences in selfevaluation of GAD under negative words stimulation,which was consistent with the social cognitive characteristics of GAD.The activation results showed that the activated brain areas were the temporoparietal area,dorsolateral anterior cingulate cortex and ventrolateral prefrontal cortex.The abnormal modulatory effects occured mainly between the temporoparietal and the dorsolateral anterior cingulate cortex,which may be the key circuit for emotional control,processing and regulation in GAD.This study has deepened our understanding of the neuropathological mechanism of GAD from the perspective of emotional processing.In conclusion,we demonstrated differences of dynamic amplitude low-frequency fluctuation over the time in GAD,which reflected the pathological features of GAD.At the same time,this study marks the first application of superiority illusion paradigm in GAD,the abnormal neural circuit in the process of self-referential was found in patients with GAD.These findings help us further understanding the neuropathological mechanisms of GAD.