Giorgio Antonio, Stromillo Maria Laura, De Leucio Alessandro, Rossi Francesca, Brandes Imke, Hakiki Bahia, Portaccio Emilio, Amato Maria Pia, De Stefano Nicola
Departments of Medicine, Surgery, and Neuroscience, University of Siena, 53100 Siena, Italy.
Departments of Medicine, Surgery, and Neuroscience, University of Siena, 53100 Siena, Italy, University of Osnabrück, 49076 Osnabrück, Germany, and.
J Neurosci. 2015 Jan 14;35(2):550-8. doi: 10.1523/JNEUROSCI.2557-14.2015.
We hypothesized that appraisal of brain connectivity may shed light on the substrate of the radiologically isolated syndrome (RIS), a term applied to asymptomatic subjects with brain MRI abnormalities highly suggestive of multiple sclerosis. We thus used a multimodal MRI approach on the human brain by modeling measures of microstructural integrity of white matter (WM) tracts with those of functional connectivity (FC) at the level of resting state networks in RIS subjects, demographically matched normal controls (NC), and relapsing-remitting (RR) MS patients, also matched with RIS for brain macrostructural damage (i.e., lesions and atrophy). Compared with NC, in both RIS subjects and MS patients altered integrity of WM tracts was present. However, RIS subjects showed, at a less conservative threshold, lower diffusivities than RRMS patients in distinct cerebral associative, commissural, projection, and cerebellar WM tracts, suggesting a relatively better anatomical connectivity. FC was similar in NC and RIS subjects, even in the presence of important risk factors for MS (spinal cord lesions, oligoclonal bands, and dissemination in time on MRI) and increased in RRMS patients in two clinically relevant networks subserving "processing" (sensorimotor) and "control" (working memory) functions. In RIS, the lack of functional reorganization in key brain networks may represent a model of "functional reserve," which may become upregulated, with an adaptive or maladaptive role, only at a later stage in case of occurrence of clinical deficit.
我们推测，对脑连接性的评估可能有助于揭示放射学孤立综合征（RIS）的基础，该术语适用于脑MRI异常高度提示多发性硬化症的无症状受试者。因此，我们对人脑采用了多模态MRI方法，通过对RIS受试者、人口统计学匹配的正常对照（NC）以及复发缓解型（RR）MS患者静息态网络水平上的白质（WM）束微观结构完整性测量与功能连接（FC）测量进行建模，RRMS患者在脑宏观结构损伤（即病变和萎缩）方面也与RIS相匹配。与NC相比，RIS受试者和MS患者均存在WM束完整性改变。然而，在较宽松的阈值下，RIS受试者在不同的大脑联合、连合、投射和小脑WM束中显示出比RRMS患者更低的扩散率，表明其解剖连接性相对更好。NC和RIS受试者的FC相似，即使存在MS的重要危险因素（脊髓病变、寡克隆带以及MRI上的时间扩散），而在RRMS患者中，在两个具有临床相关性的网络（分别服务于“处理”（感觉运动）和“控制”（工作记忆）功能）中FC增加。在RIS中，关键脑网络缺乏功能重组可能代表一种“功能储备”模式，只有在临床缺陷出现的后期，这种模式可能会以适应性或适应不良的方式上调。
