Analysis And Research Of Stroke Brain Network Based On Motor Imagination

Stroke is a kind of disease caused by acute local cerebrovascular variation.The human brain forms complex brain networks by the connection between synapses between neurons.The brain network is one of the important methods to study brain science as well as the crucial means of studying cerebral stroke.Motor imagery is also a motion state,it refers to people imagine activities in the mind while the body does not produce any real activities.Motor imagery activates relevant memories in the brain,complying with the mechanism of central nervous system motor control,thus arousing the corresponding brain regions without the need for actual movement.Starting with EGG and brain network,this paper mainly studied the characteristics of functional brain network and brain effect network in stroke patients.In the research of brain network,it discussed phase synchronous and Granger causality model,on that basis,the brain function network and brain effect network were developed,the experiment reveals the influence of stroke focus on the motor neural mechanism of cerebral cortex when patients perform the mental rotation motor imagery in each stage.This paper explored the influence of network global attribute change and network connection mechanism on the dynamic process of motor imagery.In the whole process of motor imagery,phase synchronous and Granger causality model were adopted firstly,it constructed the representative value matrix of the brain network of the two groups of motor imagery,calculated the network attribute of each of choosing objects of the two groups(the stroke group and the normal control group)in the whole process of mental rotation motor imagery cognitive task,compared the global property changes in this process and the differences between the two network properties.It has been found that the stroke patients of the two types of networks performed worse in the occipital lobe,parietal lobe,central region and other motion related areas,while the clustering coefficient,characteristic path and global efficiency of the functional network and effect network shared the same trend in general,but the clustering coefficient of the functional network was more stable,and the characteristic path was larger,which may be related to no direction of the functional network and the enlarged connection path between two nodes.It proposed to explore the effect of stroke on the mechanism of neural connection in the process of motor imagination by using the characteristics of brain connection map of EEG.The study found that the occipital and frontal lobes and the parietal were the first areas affected,then,the and central regions of the left hemisphere during the dynamic execution of motor imagery in stroke patients.In the phase of Stimulus encoding,the decrease of connectivity between occipital and frontal lobes led to the decrease of brain coding ability;in the phase of mental rotation,it showed the decrease of left brain analysis and processing ability;in the phase of response execution,the connectivity of left brain activity was obviously damaged,while the connectivity on the uninjured side was strengthened,and connectivity compensation phenomenon appeared,generally speaking,the network connection efficiency of stroke patients was reduced,and the brain signal processing function and message transmission ability were seriously damaged.A correlation method has been put forward to study the coupling between functional brain network and brain effect network,and a kinds of Pearson correlation methods are designed to calculate the coupling between them.It has been discovered that the network coupling of the stroke patients group was lower than that of the normal control group,and was negatively correlated with the length of stroke onset and stroke lesions can reduce network coupling,which increased the understanding of the network of the topological mechanism of stroke.This paper studied the various stages of motor imagination cognitive task and explored the differences in different characteristics and state changes between stroke patients and normal patients from the perspective of brain network.These studies have certain practical value for the later diagnosis and rehabilitation of stroke.