| Background:Approximately 50-85%of patients experience motor dysfunction after a stroke.Evidence from Evidence-based medicine shows that acupuncture can improve neurological damage in stroke patients,and Yanglingquan point is one of the commonly used points for treating stroke.Based on functional magnetic resonance imaging(fMRI)technology,research on the mechanism of acupuncture brain imaging has gradually entered a relatively visual stage.The premise of traditional fMRI scanning is to assume that the brain blood oxygen level dependent(BOLD)signal is stationary in time during scanning.In fact,the fMRI data during the entire scanning period has great dynamism,containing a lot of rich temporal feature information.Currently,research is mainly focused on exploring the static connectivity(Functional Connectivity,Effect Connectivity)of brain networks.The research model combining dynamic and static connectivity may provide a more comprehensive understanding of the impact of acupuncture on brain network connectivity.Objective:This study is based on functional magnetic resonance technology,with functional brain networks as the study sites.The issue surrounding the time-varying properties of brain network connectivity after resting-state fMRI scans.To explore the changes in static and dynamic connectivity of the brain network after stroke hemiplegia,as well as the static connectivity changes and temporal dynamic characteristics caused by acupuncture at the true and sham acupoints of Yanglingquan under physiological conditions and in stroke hemiplegia patients.Methods:Study 1 Fifty-two patients with stroke hemiplegia with right motor pathway injury within 3 months of onset and 51 healthy subjects matched with their gender and age were included for scans of resting-state functional MRI.Independent component analysis technique wasapplied to extract group-level functional brain networks,and static connectivity(Functional Connectivity,Effect Connectivity)changes in brain networks after stroke hemiparesis were observed using GIFT and DynamicBC software.After that,the temporal dynamic characteristics of brain network connectivity after stroke were explored with the help of sliding time window techniqueh and cluster analysis.Study 2 The subjects were divided into the healthy Yanglingquan true acupoint group(34 subjects)and sham acupoint group(17 subjects),and the Yanglingquan true acupoint group(35 subjects)and sham acupoint group(17 subjects)in stroke patients by a random number table in the ratio of 2:1.The scans of functional magnetic resonance of the acupuncture state were performed.Using the study-one data analysis method,the static connectivity(functional connectivity,effect connectivity)changes in the brain network induced by acupuncture of true and sham acupoint in Yanglingquan in the physiological state and in stroke patients with hemiplegia and their temporal dynamic characteristics were explored by comparing before and after acupuncture of true and sham acupoint and between groups.Results:Study 1 Temporal dynamics of brain network connectivity in patients with stroke hemiplegia 1 Changes in dynamic connectivity states at the subject group levelFunctional connectivity:There were four recurrent connectivity states of dynamic brain network functional connectivity at the level of the subject group.State 1 mainly shows the overall positive high connectivity state within the Sensorimotor Network(SMN),Default Mode Network(DMN),Executive Control Network(ECN)network,and between networks,accounting for 20%of the total window.State 2 is mainly manifested as an overall low connection state,accounting for 36%of the total window,and is the most common connection state among the four states.State 3 mainly shows the positive high connectivity within the DMN network,accounting for 18%of the total window.State 4 mainly shows negative connection between SMN and DMN and ECN,positive connection state within DMN and ECN networks and between networks,accounting for 25%of the total window,which is more similar to the connection state of static functional connection matrix.Effect connectivity:There are 2 recurring connection states in the analysis of dynamic effect connectivity:state 1 has a frequency of 28.30%,which mainly shows a high effect connectivity state;state 2 is a low effect connectivity state with a small overall Granger causality effect value,with a frequency of 71.70%,which is the most common type of effect connectivity state.2 Alterations in brain network connectivity in stroke patientsFunctional connectivity:Compared to sFNC in healthy subjects,functional connectivity between SMN and RECN was elevated in stroke patients,as well as between DMN and LECN.Compared to dFNC in healthy subjects,stroke patients showed an increase in functional connectivity within the DMN and between DMN and LECN in state 1;The functional connection between DMN and LECN increases in state 2;The functional connection between SMN and RECN increases in state 4.Temporal attribute indexes showed that stroke patients had reduced time fraction,mean residence time in state 3(P<0.05).Effect connectivity:The effect connectivity of DMN→ECN was enhanced in stroke patients compared to sEC in healthy subjects.Compared to healthy subjects with dEC,stroke patients had reduced effect connectivity of SMN→RECN in state 1 and elevated effect connectivity between DMN and LECN in both directions.Intra-DMN effect connectivity were elevated in state 2.The temporal attribute index showed an increased number of transitions in effector connections in stroke patients(P<0.05).Study 2 Temporal dynamics of acupuncture Yanglingquan on brain network connectivity1 Effect of acupuncture at Yanglingquan sham acupoint on brain network connectivity in healthy subjectsFunctional connectivity:No significant changes in sFNC were observed in healthy subjects after acupuncture at sham acupoint compared with the resting state before acupuncture.dFNC intra-group comparison showed that functional connectivity between DMN and LECN was reduced in healthy subjects after acupuncture at sham acupoint in state 3(P<0.05).Effect connectivity:Compared with the resting state before acupuncture,sEC in healthy subjects after sham acupoint mainly showed reduced effect connectivity within the DMN.dEC intra-group comparison showed that:The effect connectivity from LECN to DMN and RECN were enhanced in both directions in state 1 after acupuncture of sham acupuncture in healthy subjects.The effect connectivity SMN→DMN was enhanced and the effect connectivity DMN→SMN and LECN were weakened in state 2.Temporal property indexes showed elevated mean dwell time in state 1 in healthy subjects after acupuncture of sham acupoint(P<0.05).2 Effect of acupuncture at Yanglingquan true acupoint on brain network connectivity in healthy subjectsFunctional connectivity:Compared to the resting state before acupuncture,sFNC in healthy subjects after acupuncture at the true acupoint mainly showed enhanced functional connectivity within the DMN.dFNC intra-group comparison showed that the functional connectivity within the DMN was also elevated in states 2,3,and 4 after acupuncture at the true acupoint in healthy subjects.In addition,reduced functional connectivity within the DMN was also observed in state 3.Temporal property indicators showed elevated time fraction,mean dwell time in state 3 in healthy subjects after acupuncture of true acupoints(P<0.05).Effect connectivity:Compared with the resting state before needling,sEC in healthy subjects after acupuncture at the true acupoint mainly showed a bidirectional increase effect connectivity between LECN and DMN.dEC within-group comparison showed that SMN→RECN effect connectivity was reduced in state 1 after acupuncture at true acupoint in healthy subjects.The SMN→DMN effect connectivity was reduced in state 2,and the DMN internal,LECN→DMN effect connectivity was increased in state 2.The temporal property index showed an increase in the number of transitions between states in healthy subjects after acupuncture of true acupoint(P<0.05).3 Effect of acupuncture at Yanglingquan sham acupoint on brain network connectivity in stroke patientsFunctional connectivity:Compared with the resting state before acupuncture,sFNC in stroke patients after acupuncture at sham acupoint mainly showed elevated functional connectivity between DMN and ECN.dFNC intra-group comparison showed that functional connectivity within DMN was elevated in state 1,functional connectivity between DMN and LECN was reduced in state 3 after acupuncture at sham acupoint in stroke patients.The temporal property index showed elevated time fraction,mean dwell time in state 1 in stroke patients after acupuncture of sham acupoint(P<0.05).Effect connectivity:No significant changes were observed in sEC after acupuncture at sham acupoint in stroke patients compared with the resting state before acupuncture.dEC intra-group comparison showed that acupuncture at sham acupoint in stroke patients had reduced DMN internal effect connectivity in state 1.The DMN→SMN effect connectivity was reduced in state 2.The temporal property index showed reduced mean dwell time in state 1 in stroke patients after acupuncture of sham acupoint(P<0.05).4 Effect of acupuncture at Yanglingquan true acupoint on brain network connectivity in stroke patientsFunctional connectivity:No significant changes were observed in sFNC after acupuncture at true acupoint in stroke patients.dFNC intra-group comparison showed that functional connectivity within DMN was elevated in state 1 after true acupoint in stroke patients.In state 2 functional connectivity within the DMN was elevated and functional connectivity between the DMN and ECN was decreased(P<0.05).Effect connectivity:Compared with the resting state before acupuncture,sEC after acupuncture at true acupoint in stroke patients mainly showed reduced DMN→SMN effect connectivity,while there were bidirectional reduced effect connectivity within DMN.dEC intra-group comparisons showed that DMN internal effect connectivity were reduced in state 1 and state 2 after acupuncture at true acupoint in stroke patients,and in addition to this,there was an elevated DMN→LECN effect connectivity in state 2.The temporal property index showed an increase in the number of transitions between states in stroke patients after acupuncture of true acupoint(P<0.05).Conclusions:The analytical approach to dynamic connectivity can uncover the rich temporal information embedded during the scanning of fMRI data.At the subject group level,there were four recurrent functional connectivity patterns in dynamic brain network functional connectivity and two effect connectivity patterns in dynamic effector connectivity.Of the two different connectivity states,the low connectivity state was the most common one in both.Brain network connectivity was altered after stroke,showing an overall pattern of enhanced connectivity in different states.Changes in functional,effect connectivity modulated by acupuncture in different connectivity states in the physiological state.True acupoint may produce more extensive connectivity alterations than sham acupoint.In the pathological state of stroke,acupuncture modulates static and dynamic brain network connectivity,adjusting the strength of functional connectivity as well as the direction of directed effect connectivity in different connectivity states. |
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