Hensel Lukas, Bonkhoff Anna K, Paul Theresa, Tscherpel Caroline, Lange Fabian, Viswanathan Shivakumar, Volz Lukas J, Eickhoff Simon B, Fink Gereon R, Grefkes Christian
Faculty of Medicine and University Hospital Cologne, Department of Neurology, University of Cologne, Cologne, Germany.
J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Neuroimage Clin. 2025 Jun 11;47:103825. doi: 10.1016/j.nicl.2025.103825.
Connectivity changes after brain lesions due to stroke are tightly linked to functional outcome. Recent analyses of fMRI time series indicate that dynamic functional network connectivity (dFNC), reflecting transient states of connectivity may capture network-level disruptions distant to the lesion site. Yet, the relevance of such dynamic connectivity patterns for motor recovery remains unclear. We, therefore, combined the analysis of static and dFNC and a repetitive transcranial magnetic stimulation (rTMS) lesion approach, to test whether dFNC provides region-specific insight into motor system reorganization after stroke. We focused on the contralesional primary motor cortex (M1) and anterior intraparietal sulcus (aIPS), two regions previously shown to modulate motor performance post-stroke in a time dependent manner. In 18 individuals in the chronic phase after stroke (with either persistent or recovered deficits) and 18 healthy participants, we analyzed static and dynamic resting-state connectivity. We then applied online rTMS intereference over contralesional aIPS and M1 during hand movement tasks to assess region-specific contributions to motor behavior. Consistent with previous studies, dFNC states were associated with persisting motor deficits, whereas static connectivity was not associated with motor outcome. dFNC but not static connectivity was associated with residual motor deficits and explained TMS-induced behavioral changes, when applying rTMS over contralesional M1. For contralesional aIPS, both static and dynamic connectivity were linked to TMS effects. This indicates that dFNC - more than static connectivity - contains information on the functional relevance of brain regions for motor outcome, specifically contralesional M1. Our results highlight the added value of temporal network analysis in understanding mechanisms of stroke recovery mechanisms.
中风导致脑损伤后的连接性变化与功能预后紧密相关。最近对功能磁共振成像时间序列的分析表明,反映连接性瞬态状态的动态功能网络连接性(dFNC)可能捕捉到远离损伤部位的网络水平破坏。然而,这种动态连接模式对运动恢复的相关性仍不清楚。因此,我们结合了静态和dFNC分析以及重复经颅磁刺激(rTMS)损伤方法,以测试dFNC是否能为中风后运动系统重组提供区域特异性见解。我们聚焦于对侧初级运动皮层(M1)和顶内沟前部(aIPS),这两个区域先前已被证明在中风后以时间依赖的方式调节运动表现。在18名中风慢性期患者(有持续或恢复的缺陷)和18名健康参与者中,我们分析了静态和动态静息态连接性。然后,我们在手部运动任务期间对损伤对侧的aIPS和M1施加在线rTMS干扰,以评估区域对运动行为的特异性贡献。与先前的研究一致,dFNC状态与持续的运动缺陷相关,而静态连接性与运动预后无关。当在损伤对侧M1上应用rTMS时,dFNC而非静态连接性与残余运动缺陷相关,并解释了TMS诱导的行为变化。对于损伤对侧的aIPS,静态和动态连接性均与TMS效应相关。这表明,与静态连接性相比,dFNC包含有关脑区对运动预后(特别是损伤对侧M1)功能相关性的信息。我们的结果突出了时间网络分析在理解中风恢复机制中的附加价值。
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