Stroke is known to cause widespread activation and connectivity changes resulting in different levels of functional impairment. Recovery of motor functions is thought to rely mainly on reorganizations within the sensorimotor cortex, but increasing attention is being paid to other cerebral regions. To investigate the motor task-related functional connectivity (FC) of the ipsilesional premotor cortex (PMC) and its relation to residual motor output after stroke in a population of mostly poorly recoverd patients. Twenty-four stroke patients (23 right handed, mean age = 52.4 ± 12.6 years) with varying levels of motor deficits underwent functional magnetic resonance imaging while performing different motor tasks (passive mobilization, motor execution, and motor imagery of an extension movement of the unaffected hand [UH] or affected hand [AH]). For the different motor tasks, analyses of cerebral activation and task-related FC of the ipsilesional lateral sensorimotor network (SMN), and particularly the premotor cortex (PMC), were performed. Compared with UH data, FC of the ipsilesional lateral SMN during the passive or active motor tasks involving the AH was decreased with regions of the ipsilesional SMN and was increased with regions of the bilateral frontal and the ipsilesional posterior parietal cortices such as the precuneus (Pcu). During passive wrist mobilization, FC between the ipsilesional PMC and the contralesional SMN was negatively correlated with residual motor function, whereas that with nonmotor regions such as the bilateral Pcu and the contralesional dorsolateral prefrontal cortex was positively correlated with the residual motor function. Cross-modal FC of the ipsilesional PMC may reflect compensation strategies after stroke. The results emphasize the importance of the PMC and other nonmotor regions as prominent nodes involved in reorganization processes after a stroke.

中文翻译：

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前运动皮层的跨模式功能连接反映了中风后的剩余运动输出。

众所周知，中风会导致广泛的激活和连接变化，从而导致不同程度的功能障碍。运动功能的恢复被认为主要依赖于感觉运动皮层内的重组，但人们越来越关注其他大脑区域。研究同侧运动前皮层 (PMC) 的运动任务相关功能连接 (FC) 及其与中风后剩余运动输出的关系，这些功能大多是康复不佳的患者。24 名具有不同程度运动缺陷的中风患者（23 名右利手，平均年龄 = 52.4 ± 12.6 岁）在执行不同的运动任务（被动活动、运动执行和伸展运动的运动想象）时接受了功能性磁共振成像。未受影响的手 [UH] 或受影响的手 [AH]）。对于不同的运动任务，进行了同侧外侧感觉运动网络 (SMN)，特别是前运动皮层 (PMC) 的大脑激活和任务相关 FC 的分析。与 UH 数据相比，在涉及 AH 的被动或主动运动任务期间，同侧 SMN 的 FC 随同侧 SMN 区域而降低，并随双侧额叶和同侧后顶叶皮质（如楔前叶（Pcu）区域）增加。 ）。在被动腕部活动期间，同侧 PMC 和对侧 SMN 之间的 FC 与残余运动功能呈负相关，而非运动区域（如双侧 Pcu 和对侧背外侧前额叶皮层）的 FC 与残余运动功能呈正相关。同侧 PMC 的跨模态 FC 可能反映中风后的代偿策略。结果强调了 PMC 和其他非运动区域作为参与中风后重组过程的突出节点的重要性。