Research On The Brain Effect Mechanism Of Acupuncture Intervention On Stroke Disease Based On The Whole Brain Function Network

Objective:Based on the graph theoretical network analysis for complex networks,this study compared the functional magnetic resonance imaging(fMRI)characteristics of the whole brain functional networks between the stroke patients and healthy subjects to investigate the pathological features of large-scale brain network after stroke.This study analyzed the dynamic changes of large-scale brain network in stroke patients before and after acupuncture intervention to explore the adjustment effect of acupuncture intervention from a macro perspective and to uncover the mechanism of acupuncture treatment in the stroke remodeling.Methods:The study enrolled 32 stroke patients with infarction located in the right motor pathway and 25 healthy subjects as the control.The fMRI was performed on both groups.The scanning included the resting state fMRI before acupuncture intervention and the fMRI after acupuncture on the left Yanglingquan(GB34)acupoint.The National Institute of Health Stroke Scale(NIHSS),the Mini-Mental State Examination(MMSE)and the Fugl-Meyer Assessment(FMA)were also applied to evaluate the clinical neurological levels of the stroke patients.Based on the graph theoretical network analysis,we constructed the whole brain functional networks,calculated the global and nodal properties of the networks,analy zed the statistical differences of network metrics between the two groups by the independent sample t-test and the changes of network metrics before and after acupuncture intervention in the stroke patients by the paired sample t-test,and analyzed the correlation between the clinical scales and the network metrics.Results:1.Global features of the whole brain networks.The whole brain functional networks of the stroke patients still had the characteristics of the small-world network,but the small-worldness was impaired,mainly due to the decline of the normalized clustering coefficient.The immediate brain effect of the acupuncture intervention on the GB34 was able to significantly improve the clustering coefficient of the post-stroke brain networks but had no significant effect on other small-world properties.The global efficiency and average local efficiency of the stroke patients were lower than those of the healthy subjects.Acupuncture intervention significantly enhanced the average local efficiency of the whole brain functional networks of the stroke patients,but the global efficiency was not significantly changed.2.Nodal features of the whole brain networks.The hubs of the whole brain functional networks of the stroke patients in the resting state included the left precentral gyrus,bilateral dorsolateral superior frontal gyri and so on.In the stroke patients with infarction in the right motor pathway,the brain regions with significant reduction of the degree were located in the ipsilesional hemisphere,including the precentral gyrus and postcentral gyrus,while the brain regions with significant increase of the degree were mainly located in the contralesional hemisphere,including the left dorsolateral superior frontal gyrus and the bilateral medial superior frontal gyrus.Acupuncture could redistribute the hubs of stroke patients.Acupuncture intervention in the stroke patients added the hubs like the left postcentral gyrus and bilateral supplementary motor areas and reduced the hubs like the left precentral gyrus.The connector hubs of the whole brain functional networks of the stroke patients in the resting state included the left precuneus,the bilateral dorsolateral superior frontal gyri and so on.Compared with healthy subjects,the stroke patients' brain regions with significantly reduced betweenness centrality were the right thalamus,bilateral inferior temporal gyri,etc.,while the brain regions with significantly increased betweenness centrality were the right medial superior frontal gyrus.The acupuncture instant effect could also redistribute the connector hubs.The connector hubs that the acupuncture intervention instantly added included the right supplementary motor area,etc.and the reduced connector hubs included the bilateral middle frontal gyri and so on.In terms of nodal local efficiency,the nodes of the whole brain functional networks of the stroke patients in the resting state with significantly increased local efficiency were the left medial superior frontal gyrus and the middle temporal gyrus,while the nodes with significantly reduced nodes efficiency were the right hemispheric orbital part of middle frontal gyrus,the superior parietal gyrus,etc.The instant brain effect of acupuncture intervention was able to significantly enhance the local efficiency of the left dorsolateral superior frontal gyrus,supplementary motor area,bilateral precentral gyri and so on.There was no reducing effect of acupuncture on the local efficiency in stroke patients.3.Correlation between the whole brain functional networks metrics and clinical scales.The average local efficiency of the stroke patients was negatively correlated with the duration after stroke onset.The longer the course of a stroke,the local efficiency of the large-scale brain functional networks showed lower level.The scores of MMSE of the stroke patients were significantly positively correlated with the local efficiency.The stroke patients with lower local efficiency were generally worse in cognition.The scores of MMSE were also positively correlated with the small-worldness.The stroke patients with lower small-worldness had lower cognitive ability.No significant correlation was found between the network metrics of the stroke patients and the NIHSS scores.There was no statistically significant correlation between the network metrics of the large-scale brain functional networks after acupuncture intervention and the duration and the scores of clinical scales of the stroke patients.Conclusions:Stroke caused the whole brain functional networks to have a trend to the random networks.The functional segregation of the brain was injured.The specialization of the brain function was impaired following a stroke,and the information transmission efficiency decreased.The instant brain effect of acupuncture could correct the randomized tendency of the large-scale brain functional networks in the stroke patients,improved the level of brain functional segregation,and enhanced the local information transmission efficiency.This might be the main mechanism of acupuncture intervention improving large-scale brain functional networks after a stroke.In addition,the ipsilesional medial superior frontal gyrus and the contralesional dorsolateral superior frontal gyrus might be important brain regions for the whole brain functional networks to play a compensatory role following a stroke.The instant acupuncture brain effect had extensive adjustments to the topological characteristics of the nodes of the whole brain functional network,especially regulating the bilateral supplementary motor areas and the bilateral precentral gyri.These might be the key brain regions for acupuncture on GB34 to promote the rehabilitation of stroke.