An FMRI Study:the Abnormal Brain Networks Of Working Memory In GTCS

Generalized tonic-clonic seizures(GTCS),a type of idiopathic generalized epilepsy,consists of generalized tonic-clonic seizures sweeping whole body and total lead electrical activity abnormalities.Routine MRI and CT examination revealed no significant structural abnormalities and the cause of diease is unknown.These irregular seizures put a heavy burden on the lives of patients and their families.More and more studies have been devoted to exploring the pathological mechanism and pathogenic factors of GTCS patients.With the rapid development of current technology,a variety of magnetic resonance research methods have been applied in GTCS patients,including electroencephalography,magnetoencephalography,diffusion tensor imaging,functional magnetic resonance imaging and magnetic resonance spectroscopy imaging.Some studies have found that GTCS patients have obvious cognitive dysfunction.In this paper,from the perspective of working memory impairment,functional magnetic resonance imaging(fMRI)and magnetic resonance spectroscopy(MRS)imaging will be used to explore the abnormalities of functions related to working memory and neurometabolic compounds in GTCS patients.In this study,57 GTCS patients and 34 gender-and age-matched healthy subjects were selected.Functional magnetic resonance(fMRI)sequences of two difficulty of working memory tasks were collected,and general linear model calculations were performed to estimate task-activated brain regions.Two-sample t-test was used to calculate the activation differences between GTCS patients and healthy subjects during memory tasks,and psychophysiological interaction was used to construct brain network connections modulated by memory tasks.The correlation between the both of courseof disease of GTCS patients and the initial age of onset and the activation of task states was calculated.Neurometabolites in the prefrontal,thalamus,and basal ganglia of patients and healthy subjects were obtained using collected multi-voxel magnetic resonance spectroscopy(MRS)imaging.Differences between patients and healthy subjects were calculated using rank sum tests,and correlations between differential compounds and task-state activation and psychophysiological interactions were calculated.The results showed that GTCS patients showed a significant increase in negative activation in the precuneus and inferior occipital gyrus tasks and a significant decrease in positive activation in the inferior parietal gyrus.We believe that this is due to the suppression of task-negative network and the insufficient activation of task-positive network caused by the damage of DMN brain region caused by the disease,which further points out that the precuneus may be a crucial node in the brain.We found an increase in the degree of directed connectivity from the precuneus to the thalamus in patients with GTCS.This may be a compensatory mechanism to compensate for the underactivation of brain regions associated with working memory.At the same time,we also found reduced connections between the precentral insula and the frontal visual area and the dorsolateral prefrontal area,which we believe is a resource regulation mechanism,resulting in decreased connectivity due to the location of resource centers in areas of the brain that are more needed for working memory.MRS results show that the patient’s thalamus n-acetyl aspartate concentration significantly reduced,anterior cingulate cortex of glutamic-glutamine concentration increased significantly,this suggests that the GTCS,in patients with thalamic neurons lost and metabolic efficiency is reduced,the anterior cingulate cortex increases the intensity of work in order to perform working memory tasks.In the subsequent correlation analysis,we also found that GTCS patients showed correlation with additional brain regions compared with healthy subjects,revealing that GTCS patients were affected by epilepsy and caused damage to related brain regions.In this study,we analyzed fMRI and MRI data,and found that both task-induced activation and biochemical metabolites in GTCS patients were different from those in healthy subjects.This study can help to explore the pathogenic factors and pathological mechanisms of generalized tonic-clonic epilepsy,and is expected to provide ideas for the subsequent localization of transcranial magnetic stimulation therapy,epilepsy diagnosis and evaluation of therapeutic effects.