Rocca Maria A, Gallo Antonio, Colombo Bruno, Falini Andrea, Scotti Giuseppe, Comi Giancarlo, Filippi Massimo
Neuroimaging Research Unit, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
Neuroimage. 2004 Sep;23(1):141-7. doi: 10.1016/j.neuroimage.2004.05.005.
Cortical functional changes, with the potential to limit the functional consequences of tissue injury, have been shown in patients with multiple sclerosis (MS). In this study, we assessed the influence of MS-related tissue damage of the brain portion of the left pyramidal tract on the corresponding movement-associated patterns of cortical recruitment in a large sample of MS patients when performing a simple motor task with their fully normal functioning right upper limbs. We investigated 76 right-handed patients with definite MS. In each subject, functional magnetic resonance imaging (fMRI) was acquired during the performance of a simple motor task with the dominant, right upper limb. During the same session, dual-echo, magnetization transfer (MT) and diffusion tensor (DT) MRI sequences were also obtained to quantify the extent and the severity of pyramidal tract damage. Lesions along the left pyramidal tract were identified in 43 patients. Compared to patients without pyramidal tract lesions, patients with such lesions had more significant activations of the contralateral primary sensorimotor cortex (SMC), secondary sensorimotor cortex (SII), inferior central sulcus, and cingulate motor area (CMA). They also showed more significant activations of several regions of the ipsilateral hemisphere, including the primary SMC and the precuneus. In these patients, T2 lesion load of left pyramidal tract was correlated with the extent of activation of the contralateral primary SMC (r2 = 0.25, P < 0.0001), whereas no correlations were found between the extent of fMRI activations and the severity of intrinsic lesion damage, as well as with left pyramidal tract normal-appearing white matter damage. This study shows that, in patients with MS, following injury of the motor pathways, there is an increased recruitment of a widespread sensorimotor network, which is likely to contribute to limit the appearance of overt clinical deficits.
在多发性硬化症（MS）患者中已显示出皮质功能变化，这种变化有可能限制组织损伤的功能后果。在本研究中，我们评估了左锥体束脑段与MS相关的组织损伤对大量MS患者在使用其功能完全正常的右上肢执行简单运动任务时相应的皮质募集运动相关模式的影响。我们调查了76名右利手的确诊MS患者。在每个受试者执行简单运动任务时，使用优势右上肢，采集功能磁共振成像（fMRI）。在同一时段，还获得了双回波、磁化传递（MT）和扩散张量（DT）MRI序列，以量化锥体束损伤的程度和严重程度。43例患者在左锥体束沿线发现病变。与无锥体束病变的患者相比，有此类病变的患者对侧初级感觉运动皮层（SMC）、次级感觉运动皮层（SII）、中央沟下部和扣带回运动区（CMA）的激活更显著。他们同侧半球的几个区域，包括初级SMC和楔前叶，也显示出更显著的激活。在这些患者中，左锥体束的T2病变负荷与对侧初级SMC的激活程度相关（r2 = 0.25，P < 0.0001），而fMRI激活程度与内在病变损伤的严重程度以及左锥体束正常外观的白质损伤之间未发现相关性。这项研究表明，在MS患者中，运动通路损伤后，广泛的感觉运动网络募集增加，这可能有助于限制明显临床缺陷的出现。
