Abstract

Hemiparesis after stroke is associated with increased neural activity not only in the lesioned but also in the contralesional hemisphere. While most studies have focused on the role of contralesional primary motor cortex (M1) activity for motor performance, data on other areas within the unaffected hemisphere are scarce, especially early after stroke. We here combined functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) to elucidate the contribution of contralesional M1, dorsal premotor cortex (dPMC), and anterior intraparietal sulcus (aIPS) for the stroke-affected hand within the first 10 days after stroke. We used “online” TMS to interfere with neural activity at subject-specific fMRI coordinates while recording 3D movement kinematics. Interfering with aIPS activity improved tapping performance in patients, but not healthy controls, suggesting a maladaptive role of this region early poststroke. Analyzing effective connectivity parameters using a Lasso prediction model revealed that behavioral TMS effects were predicted by the coupling of the stimulated aIPS with dPMC and ipsilesional M1. In conclusion, we found a strong link between patterns of frontoparietal connectivity and TMS effects, indicating a detrimental influence of the contralesional aIPS on motor performance early after stroke.

中文翻译：

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对侧脑区对中风后早期运动表现的连接相关作用

摘要

中风后的偏瘫不仅与受损半球的神经活动增加有关，而且与对侧半球的神经活动增加有关。虽然大多数研究都集中在对侧初级运动皮层 (M1) 活动对运动表现的作用，但未受影响半球内其他区域的数据很少，尤其是中风后早期。我们在这里结合功能性磁共振成像 (fMRI) 和经颅磁刺激 (TMS) 来阐明对侧 M1、背侧运动前皮层 (dPMC) 和前顶内沟 (aIPS) 在头 10 天内对中风影响手的贡献中风后。我们使用“在线”TMS 来干扰特定对象 fMRI 坐标的神经活动，同时记录 3D 运动运动学。干扰 aIPS 活动可改善患者的敲击表现，但不是健康对照，表明该区域在中风后早期的适应不良作用。使用 Lasso 预测模型分析有效连接参数表明，行为 TMS 效应是通过受刺激的 aIPS 与 dPMC 和同侧 M1 的耦合来预测的。总之，我们发现额顶连接模式和 TMS 效应之间存在密切联系，表明对侧 aIPS 对中风后早期运动表现的不利影响。