Lee M, Reddy H, Johansen-Berg H, Pendlebury S, Jenkinson M, Smith S, Palace J, Matthews P M
Centre for Functional Magnetic Resonance Imaging of the Brain, Department of Clincal Neurology, University of Oxford, John Radcliffe Hospital, UK.
Ann Neurol. 2000 May;47(5):606-13.
Although multiple sclerosis (MS) is an inflammatory demyelinating disease, there can be substantial axonal injury and loss. We therefore hypothesized that adaptive cortical changes may contribute to limiting functional impairment, particularly in the early stages of the disease. To test our hypothesis, we used functional magnetic resonance imaging (MRI) to characterize the localization and volumes of activation in the motor cortex during simple flexion-extension finger movements. There were differences in the patterns of cortical activation with movement between the 12 MS patients and the 12 normal controls. All patients showed greater relative supplementary motor area activation than did the normal controls. The relative hemispheric lateralization of sensorimotor cortex (SMC) activation decreased in direct proportion to the total cerebral T2-weighted MRI hyperintense lesion load. This appeared to be due primarily to increases in ipsilateral SMC activation with increasing lesion load in white matter of the hemisphere contralateral to the limb moved. The center of activation in the contralateral SMC was shifted a mean of 8.8 mm posterior in patients relative to controls, providing additional evidence for cortical adaptive responses to injury. The magnitude of this posterior shift in the SMC activation increased with greater T2 lesion loads. These observations demonstrate that cortical recruitment for simple finger movements can change both quantitatively and qualitatively in the SMCs of MS patients, suggesting that cortical reorganization or "unmasking" of latent pathways can contribute to functional recovery. These adaptive changes are another factor potentially limiting the strength of the relationship between MRI measures of pathology and clinical measures of disability.
尽管多发性硬化症（MS）是一种炎性脱髓鞘疾病，但仍可能存在大量轴突损伤和损失。因此，我们推测适应性皮质变化可能有助于限制功能损害，尤其是在疾病的早期阶段。为了验证我们的假设，我们使用功能磁共振成像（MRI）来表征在简单的手指屈伸运动过程中运动皮质激活的定位和体积。12例MS患者和12例正常对照者在运动时皮质激活模式存在差异。所有患者的辅助运动区相对激活程度均高于正常对照者。感觉运动皮质（SMC）激活的相对半球侧化与全脑T2加权MRI高信号病变负荷成反比。这似乎主要是由于随着对侧肢体白质病变负荷增加，同侧SMC激活增加所致。相对于对照组，患者对侧SMC的激活中心平均向后移位8.8毫米，为皮质对损伤的适应性反应提供了额外证据。SMC激活的这种向后移位幅度随着T2病变负荷的增加而增大。这些观察结果表明，MS患者的SMC中，简单手指运动的皮质募集在数量和质量上都可能发生变化，这表明皮质重组或潜在通路的“揭露”有助于功能恢复。这些适应性变化是另一个可能限制病理MRI测量与残疾临床测量之间关系强度的因素。
