FMRI Study Of Supplementary Motor Area After Ischemic Stroke

Objective:To explored the neural mechanisms of motor systemrecovery after ischemic stroke, we observed the cortical structural changescaused by ischemic stroke and related functional reorganization in ischemicstroke patients by investigating changes in cortical thickness,ReHo,fALFF andthe ralated resting-state functional connectivity magnetic resonanceimaging(rs-fMRI) changes in supplemenarty motor area.Methods:twentyischemic stroke patients (12males and8females) with a unilateral subcorticalischemic stroke were compared with twenty-three age-and sex-matchedhealthy participants (10males and13females).Siemens Tim Trio3.0T MRScanner with a8-channel head coil was used to obtain high resolutionsanatomy images and fMRI data in resting state. Cortical thickness wascalculated using Freesurfer V.5.1.0software. The rs-fMRI data were processedwith the software of Matlab2011b,DPARSFA and REST. We definedipsilesional supplementary motor area as ROIs for the ReHo and fALFFanalyses and voxel-based functional connectivity analyses. The ROI-basedgroup comparisons of cortical thickness、ReHo and fALFF were performedusing GLM with age and gender. Group comparison of functionalconnectivity were performed using two-sample t-test in REST controlling forage and gender.Results:We found a significant changed area in ipsilesionalsupplementary motor area of cortical thickness in ischemic stroke patients compared to healthy subjects (using a single vertex threshold,p <0.05,uncorrected) with a cluster size threshold of p <0.05).The ReHo analysis showthat patients had higher ReHo values than healthy subjects in ipsilesionalsupplementary motor area (p <0.05, uncorrected).The fALFF analysis showthat patients had lower fALFF values than healthy subjects in ipsilesionalsupplementary motor area (p <0.05, uncorrected). Compared with healthysubjects,patients revealed increased functional connectivity with theipsilesional primary motor area and contralesional supplementary motor area.On the contrary, functional in connectivity with the bilateral cerebellum,contralesional primary motor area were decreased in patients with stroke(using a single voxel threshold, p <0.05, uncorrected) with FDR corrected (p<0.05.at the cluster level).Conclusions:1.Ischemic stroke of subcorticalinduced structural changes in ipsilesional supplementary motor area whichmay inferred structural injury in remoted cortical area from lesion area in theearly;2.Decreased fALFF and increased ReHo value in supplementary motorarea suggested higher functional synchronization and efficiency forinformation transferring and processing, as compensatory mechanism forstructural damage;3.Changed functional connectivity in patients of the injuredSMA with bilateral PM、M1、CMA and contralesional SMA.It is suggestedthat stroke may due to functional changes in other related brain areas asanother compensatory mechanism and functional reorganization foripsilesional area.