Studies On Effective Connectivity Of Brain Networks Based On Functional Magnetic Resonance Imaging

In the functional integration studies of the brain,effective connectivity is an important element that can reveal information about the causal effects of the connectivity between neural signals in the brain.In this paper,we focus on effective connectivity and investigate the atypical alterations in brain connectivity among patients with in Juvenile myoclonic epilepsy(JME)patients around functional magnetic resonance imaging(f MRI)data to further investigate the neural mechanism of disease occurrence and provide an aid for the clinical diagnosis of epilepsy diseases.The main study of this paper is as follows:(1)Optimization of Spectral Dynamic Causal Modeling(sp DCM)and its application in healthy subjects.In this study,the traditional sphere extraction method was used to extract white matter and cerebrospinal fluid,and the parameters were optimized to address the problem.The study used the Human Connectome Project(HCP)dataset to analyze the connectivity differences within the default mode network(DMN)of healthy subjects.The results indicated notable variations in effective connectivity among the medial prefrontal cortex to the posterior cingulate gyrus and the left inferior parietal gyrus to the right inferior parietal gyrus in men compared to women,reflecting differences in the cognitive and emotional processing abilities of men and women.(2)To further investigate changes in effective connectivity within the default mode network of JME patients.In this study,data-driven Independent Component Analysis(ICA)was used to compare the differences in f MRI data between the JME patient group and the healthy control group,and the brain regions of the differential data were defined.Eight brain regions in DMN were finally identified,including anterior cingulate gyrus,posterior cingulate gyrus,precuneus,medial prefrontal cortex,hippocampus,middle occipital gyrus,lingual gyrus and peritallofiscus cortex.Eight brain regions were taken as areas of interest,and the optimized sp DCM was used for effective connection analysis.A Bayesian simplified model was used to generate a comparable optimal model between a JME patient group and a healthy control group.The results showed that compared with normal individuals,JME patients had an enhanced effective connectivity strength of 6 connections,including precuneus to anterior cingulate gyrus,medial prefrontal cortex to hippocampus,lingual gyrus to hippocampus,hippocampus to precuneus,hippocampal to lingual gyrus,and the Calcarine cortex to the precuneus.This indicates that these regions,as central receptors,are disrupted in the interaction,thereby enhancing the response effect,The increased information flow reflects that these brain regions have obstacles in generating and receiving effects on other DMN regions.On the contrary,the effective connectivity strength of self-connection of lingual gyrus and anterior cingulate gyrus decreased,indicating that the flow of causal influence of these regions was inhibited,and the transmission of information between brain regions was blocked,resulting in the abnormal sharing of information with other brain regions and causing the abnormal behavior of patients.The study of brain network changes using effective connections provides important clues to reveal the core brain regions of the disease.