Mintzopoulos Dionyssios, Astrakas Loukas G, Khanicheh Azadeh, Konstas Angelos A, Singhal Aneesh, Moskowitz Michael A, Rosen Bruce R, Tzika A Aria
NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital and Shriner's Burn Institute, Harvard Medical School, Boston, MA 02114, USA.
Neuroimage. 2009 Aug;47 Suppl 2:T90-7. doi: 10.1016/j.neuroimage.2009.03.007. Epub 2009 Mar 12.
The aim of this study was to investigate functional reorganization of motor systems by probing connectivity between motor related areas in chronic stroke patients using functional magnetic resonance imaging (fMRI) in conjunction with a novel MR-compatible hand-induced, robotic device (MR_CHIROD). We evaluated data sets obtained from healthy volunteers and right-hand-dominant patients with first-ever left-sided stroke > or =6 months prior and mild to moderate hemiparesis affecting the right hand. We acquired T1-weighted echo planar and fluid attenuation inversion recovery MR images and multi-level fMRI data using parallel imaging by means of the GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) algorithm on a 3 T MR system. Participants underwent fMRI while performing a motor task with the MR_CHIROD in the MR scanner. Changes in effective connectivity among a network of primary motor cortex (M1), supplementary motor area (SMA) and cerebellum (Ce) were assessed using dynamic causal modeling. Relative to healthy controls, stroke patients exhibited decreased intrinsic neural coupling between M1 and Ce, which was consistent with a dysfunctional M1 to Ce connection. Stroke patients also showed increased SMA to M1 and SMA to cerebellum coupling, suggesting that changes in SMA and Ce connectivity may occur to compensate for a dysfunctional M1. The results demonstrate for the first time that connectivity alterations between motor areas may help counterbalance a functionally abnormal M1 in chronic stroke patients. Assessing changes in connectivity by means of fMRI and MR_CHIROD might be used in the future to further elucidate the neural network plasticity that underlies functional recovery in chronic stroke patients.
本研究的目的是通过使用功能磁共振成像（fMRI）结合一种新型的与磁共振兼容的手部诱导机器人装置（MR_CHIROD），探测慢性中风患者运动相关区域之间的连接性，来研究运动系统的功能重组。我们评估了从健康志愿者以及首次发生左侧中风且时间≥6个月、右手有轻度至中度偏瘫的右利手患者获得的数据集。我们在3T磁共振系统上，通过广义自校准部分并行采集（GRAPPA）算法的并行成像，获取了T1加权回波平面和液体衰减反转恢复磁共振图像以及多级fMRI数据。参与者在磁共振扫描仪中使用MR_CHIROD执行运动任务时接受fMRI检查。使用动态因果模型评估初级运动皮层（M1）、辅助运动区（SMA）和小脑（Ce）网络之间有效连接性的变化。与健康对照相比，中风患者M1和Ce之间的内在神经耦合降低，这与M1到Ce连接功能障碍一致。中风患者还表现出SMA到M1以及SMA到小脑的耦合增加，表明SMA和Ce连接性的变化可能是为了补偿功能失调的M1。结果首次证明，运动区域之间的连接性改变可能有助于平衡慢性中风患者功能异常的M1。未来，通过fMRI和MR_CHIROD评估连接性变化可能用于进一步阐明慢性中风患者功能恢复背后的神经网络可塑性。
