Functional Reorganization of the Brain in Humans Following Spinal Cord Injury: Evidence for Underlying Changes in Cortical Anatomy
Functional Reorganization of the Brain in Humans Following Spinal Cord Injury: Evidence for Underlying Changes in Cortical Anatomy
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DOI：
10.1523/jneurosci.2717-10.2011
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发表时间：
2011-02-16
影响因子：
5.3
通讯作者：
Siddall, Philip J.
中科院分区：
文献类型：
--
作者：
Henderson, Luke A.;Gustin, Sylvia M.;Siddall, Philip J.
躯体感觉驱动的丧失导致初级躯体感觉皮层（SI）的功能重组。虽然功能性皮层重组的现象已经得到了很好的证实，但在人类中，功能性重组是由大脑解剖结构的变化引起的，还是仅仅反映了已经存在的休眠突触的暴露，仍然是未知的。在20例完全性胸脊髓损伤（SCI）和23例对照者中，我们使用功能和结构磁共振成像来确定SI重组是否与SI解剖结构的变化相关。SCI导致显著的SI重组，小指代表向内侧移动到下体代表（即，感觉丧失区）。此外，尽管SCI与下半身代表的灰质体积损失有关，但随着重组的增加，这种损失最小化。也就是说，小指代表的内侧移位越大，下半身代表的灰质保留越大。此外，在最大SI重组的区域（小指），分数各向异性与SI重组。也就是说，随着SI重组的增加，对齐结构的程度降低。最后，虽然丘脑皮质纤维保持不变，但小指代表内的水运动的容易程度和方向发生了改变，在SCI受试者中更倾向于中线。这些数据表明，脊髓损伤后SI重组与SI解剖结构的变化有关，并提供了令人信服的证据表明，人类SI重组是由于新的横向连接的生长，而不仅仅是由于已经存在的横向连接的暴露。
Loss of somatosensory drive results in functional reorganization of the primary somatosensory cortex (SI). While the phenomenon of functional cortical reorganization is well established, it remains unknown whether in humans, functional reorganization results from changes in brain anatomy, or simply reflects an unmasking of already existing dormant synapses. In 20 subjects with complete thoracic spinal cord injuries (SCIs) and 23 controls, we used functional and structural magnetic resonance imaging to determine whether SI reorganization was associated with changes in SI anatomy. SCI resulted in a significant SI reorganization, with the little finger representation moving medially toward the lower body representation (i.e., area of sensory loss). Furthermore, although SCI was associated with gray matter volume loss in the lower body representation, this loss was minimized as reorganization increased. That is, the greater the medial shift in little finger representation, the greater the gray matter preservation in the lower body representation. In addition, in the region of greatest SI reorganization (little finger), fractional anisotropy was correlated with SI reorganization. That is, as SI reorganization increased, the extent of aligned structures decreased. Finally, although thalamocortical fibers remained unchanged, the ease and direction of water movement within the little finger representation was altered, being directed more toward the midline in SCI subjects. These data show that SI reorganization following SCI is associated with changes in SI anatomy and provide compelling evidence that SI reorganization in humans results from the growth of new lateral connections, and not simply from the unmasking of already existing lateral connections.