Medical Faculty, Goethe University Frankfurt, Department of Neurology, Frankfurt University Hospital, Frankfurt am Main, Germany.
Medical Faculty, University of Cologne, Department of Neurology, University Hospital Cologne, Cologne, Germany.
Neuroimage. 2024 Oct 15;300:120828. doi: 10.1016/j.neuroimage.2024.120828. Epub 2024 Sep 17.
The concept of structural reserve in stroke reorganization assumes that the relevance of the contralesional hemisphere strongly depends on the brain tissue spared by the lesion in the affected hemisphere. Recent studies, however, have indicated that the contralesional hemisphere's impact exhibits region-specific variability with concurrently existing maladaptive and supportive influences. This challenges traditional views, necessitating a nuanced investigation of contralesional motor areas and their interaction with ipsilesional networks. Our study focused on the functional role of contralesional key motor areas and lesion-induced connectome disruption early after stroke. Online TMS data of twenty-five stroke patients was analyzed to disentangle interindividual differences in the functional roles of contralesional primary motor cortex (M1), dorsal premotor cortex (dPMC), and anterior interparietal sulcus (aIPS) for motor function. Connectome-based lesion symptom mapping and corticospinal tract lesion quantification were used to investigate how TMS effects depend on ipsilesional structural network properties. At group and individual levels, TMS interference with contralesional M1 and aIPS but not dPMC led to improved performance early after stroke. At the connectome level, a more disturbing role of contralesional M1 was related to a more severe disruption of the structural integrity of ipsilesional M1 in the affected motor network. In contrast, a detrimental influence of contralesional aIPS was linked to less disruption of the ipsilesional M1 connectivity. Our findings indicate that contralesional areas distinctively interfere with motor performance early after stroke depending on ipsilesional structural integrity, extending the concept of structural reserve to regional specificity in recovery of function.
中风重组的结构储备概念假设，对侧半球的相关性强烈取决于受影响半球的病变所保留的脑组织。然而，最近的研究表明，对侧半球的影响表现出与区域特异性相关的可变性，同时存在适应性和支持性的影响。这挑战了传统观点，需要对侧运动区及其与同侧网络的相互作用进行细致的研究。我们的研究重点是中风后早期对侧关键运动区的功能作用和损伤引起的连接体中断。对 25 名中风患者的在线 TMS 数据进行了分析，以区分对侧初级运动皮层（M1）、背侧运动前皮层（dPMC）和前顶内沟（aIPS）对运动功能的个体间差异的功能作用。基于连接体的损伤症状映射和皮质脊髓束损伤定量用于研究 TMS 效应如何取决于同侧结构网络特性。在组和个体水平上，TMS 干扰对侧 M1 和 aIPS，但不干扰 dPMC，导致中风后早期运动功能改善。在连接体水平上，对侧 M1 的破坏性作用与其在受影响的运动网络中同侧 M1 结构完整性的严重破坏有关。相比之下，对侧 aIPS 的有害影响与同侧 M1 连接的破坏程度较小有关。我们的发现表明，中风后早期，对侧区域根据同侧结构完整性对运动性能有明显的干扰，将结构储备的概念扩展到功能恢复的区域特异性。
