Lenzi Delia, Conte Antonella, Mainero Caterina, Frasca Vittorio, Fubelli Federica, Totaro Porzia, Caramia Francesca, Inghilleri Maurizio, Pozzilli Carlo, Pantano Patrizia
Department of Neurological Sciences, University of Rome La Sapienza, Rome, Italy.
Hum Brain Mapp. 2007 Jul;28(7):636-44. doi: 10.1002/hbm.20305.
Functional MRI (fMRI) studies have shown increased activation of ipsilateral motor areas during hand movement in patients with multiple sclerosis (MS). We hypothesized that these changes could be due to disruption of transcallosal inhibitory pathways. We studied 18 patients with relapsing-remitting MS. Conventional T1- and T2-weighted images were acquired and lesion load (LL) measured. Diffusion tensor imaging (DTI) was performed to estimate fractional anisotropy (FA) and mean diffusivity (MD) in the body of the corpus callosum (CC). fMRI was obtained during a right-hand motor task. Patients were studied to evaluate transcallosal inhibition (TCI, latency and duration) and central conduction time (CCT). Eighteen normal subjects were studied with the same techniques. Patients showed increased MD (P < 0.0005) and reduced FA (P < 0.0005) in the body of the CC. Mean latency and duration of TCI were altered in 12 patients and absent in the others. Between-group analysis showed greater activation in patients in bilateral premotor, primary motor (M1), and middle cingulate cortices and in the ipsilateral supplementary motor area, insula, and thalamus. A multivariate analysis between activation patterns, structural MRI, and neurophysiological findings demonstrated positive correlations between T1-LL, MD in the body of CC, and activation of the ipsilateral motor cortex (iM1) in patients. Duration of TCI was negatively correlated with activation in the iM1. Our data suggest that functional changes in iM1 in patients with MS during a motor task partially represents a consequence of loss of transcallosal inhibitory fibers.
功能磁共振成像（fMRI）研究表明，多发性硬化症（MS）患者在手部运动期间同侧运动区的激活增加。我们推测这些变化可能是由于胼胝体抑制通路的破坏所致。我们研究了18例复发缓解型MS患者。采集了常规T1加权和T2加权图像并测量病变负荷（LL）。进行扩散张量成像（DTI）以估计胼胝体（CC）体部的各向异性分数（FA）和平均扩散率（MD）。在右手运动任务期间获得fMRI。对患者进行研究以评估胼胝体抑制（TCI，潜伏期和持续时间）和中枢传导时间（CCT）。用相同技术研究了18名正常受试者。患者的CC体部MD增加（P <0.0005），FA降低（P <0.0005）。12例患者的TCI平均潜伏期和持续时间发生改变，其他患者则无。组间分析显示，双侧运动前区、初级运动区（M1）和扣带中部皮质以及同侧辅助运动区、岛叶和丘脑的患者激活更强。激活模式、结构MRI和神经生理学结果之间的多变量分析表明，患者的T1-LL、CC体部的MD与同侧运动皮质（iM1）的激活之间存在正相关。TCI的持续时间与iM1的激活呈负相关。我们的数据表明，MS患者在运动任务期间iM1的功能变化部分代表了胼胝体抑制纤维丧失的结果。
