Helekar Santosh A, Shin Jae C, Mattson Brandi J, Bartley Krystle, Stosic Milena, Saldana-King Toni, Montague P Read, Hutton George J
Department of Neuroscience, Baylor College of Medicine Houston, TX, USA.
Front Hum Neurosci. 2010 Nov 22;4:219. doi: 10.3389/fnhum.2010.00219. eCollection 2010.
In multiple sclerosis (MS) functional changes in connectivity due to cortical reorganization could lead to cognitive impairment (CI), or reflect a re-adjustment to reduce the clinical effects of widespread tissue damage. Such alterations in connectivity could result in changes in neural activation as assayed by executive function tasks. We examined cognitive function in MS patients with mild to moderate CI and age-matched controls. We evaluated brain activity using functional magnetic resonance imaging (fMRI) during the successful performance of the Wisconsin card sorting (WCS) task by MS patients, showing compensatory maintenance of normal function, as measured by response latency and error rate. To assess changes in functional connectivity throughout the brain, we performed a global functional brain network analysis by computing voxel-by-voxel correlations on the fMRI time series data and carrying out a hierarchical cluster analysis. We found that during the WCS task there is a significant reduction in the number of smaller size brain functional networks, and a change in the brain areas representing the nodes of these networks in MS patients compared to age-matched controls. There is also a concomitant increase in the strength of functional connections between brain loci separated at intermediate-scale distances in these patients. These functional alterations might reflect compensatory neuroplastic reorganization underlying maintenance of relatively normal cognitive function in the face of white matter lesions and cortical atrophy produced by MS.
在多发性硬化症（MS）中，由于皮质重组导致的连接性功能变化可能会导致认知障碍（CI），或者反映出一种重新调整以减轻广泛组织损伤的临床影响。这种连接性的改变可能会导致在执行功能任务时所检测到的神经激活变化。我们研究了患有轻度至中度CI的MS患者以及年龄匹配的对照组的认知功能。在MS患者成功完成威斯康星卡片分类（WCS）任务期间，我们使用功能磁共振成像（fMRI）评估大脑活动，通过反应潜伏期和错误率来衡量，结果显示正常功能得到了代偿性维持。为了评估全脑功能连接性的变化，我们通过对fMRI时间序列数据逐体素计算相关性并进行层次聚类分析，进行了全脑功能网络分析。我们发现，在WCS任务期间，与年龄匹配的对照组相比，MS患者中较小尺寸脑功能网络的数量显著减少，并且代表这些网络节点的脑区发生了变化。这些患者在中等尺度距离上分离的脑区之间的功能连接强度也随之增加。这些功能改变可能反映了在面对MS所产生的白质病变和皮质萎缩时，维持相对正常认知功能背后的代偿性神经可塑性重组。
