Characters Of Positive And Negative Network Functional Connectivity Changes Related To Hand Knob Area After Stroke

Functional magnetic resonance imaging(f MRI)studies have suggested abnormalities in brain functional connectivity(FC)in stroke patients with motor dysfunction.Although the changes of positive-correlated brain network connectivity after stroke have been extensively investigated,the negative-correlated brain network connectivity remains unknown.The purpose of this study is to explore the changes of positive and negative network connectivity related to hand knob area and their correlation with motor dysfunction after subcortical stroke.In this study,18 unilateral subcortical stroke patients(stroke group)and 18 healthy controlss(HCs)with matched gender and age were examined by resting state f MRI(rs-f MRI).The primary motor cotex(M1,corresponding to the lesion side)related to hand knob area was selected as the region of interest(ROI),and the positive and negative network based on the Voxel-wise whole brain functional connectivity method were analyzed;the intra-network and inter-network of the two networks based on the ROI-wise functional connectivity method were also analyzed.Finally,the abnormal functional connectivity index were correlated with Fugul-Meyer Assessment of upper extremity(FM-UE)scores in stroke patients.The results showed,compared with healthy controls(HCs),some brain regions with significantly lower FC with the M1 in the stroke group were all within the positive network;while other brain regions with significantly greater FC with the M1 were all within the negative functional network;and the FC values between the ipsilesional M1 and the ipsilesional middle frontal gyrus were negatively correlated with the FM-UE scores(r = 0.735 P < 0.01);the mean FC both decreased significantly within and between the two anti-correlated networks,but had no significant correlation with the FM-UE scores(P > 0.05);besides,the percentages of the total FC numbers of the two anti-correlated networks decreased in the stroke group,which were positively correlated with the FM-UE scores(r = 0.476,P < 0.05).The results suggested,the averaged connectivity strength of the positive and negative network related to hand knob area both decrease following subcortical stroke.In particular,the FC in the stroke group greater than that in the control group does not mean "functional compensation",but reflects the degradation FC in the brain regions related to hand knob area.Besides,FC between the prefrontal lobe(middle frontal gyrus)and i M1 and the FC integrity of the two networks may be objective reference for evaluating hand motor dysfunction after stroke.Thus,it may be helpful for our deep understanding of the neuropathyological mechanism of stroke and provide reference for rehabilitation intervention.