Burton Harold, Dixit Sachin, Litkowski Patricia, Wingert Jason R
Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri 63110, USA.
Somatosens Mot Res. 2009 Dec;26(4):90-104. doi: 10.3109/08990220903335742.
Functional connectivity (fcMRI) was analyzed in individuals with spastic diplegia and age-matched controls. Pearson correlations (r-values) were computed between resting state spontaneous activity in selected seed regions (sROI) and each voxel throughout the brain. Seed ROI were centered on foci activated by tactile stimulation of the second fingertip in somatosensory and parietal dorsal attention regions. The group with diplegia showed significantly expanded networks for the somatomotor but not dorsal attention areas. These expanded networks overran nearly all topological representations in somatosensory and motor areas despite a sROI in a fingertip focus. A possible underlying cause for altered fcMRI in the group with dipegia, and generally sensorimotor deficits in spastic diplegia, is that prenatal third trimester white-matter injury leads to localized damage to subplate neurons. We hypothesize that intracortical connections become dominant in spastic diplegia through successful competition with diminished or absent thalamocortical inputs. Similar to the effects of subplate ablations on ocular dominance columns (Kanold and Shatz, Neuron 2006;51:627-638), a spike timing-dependent plasticity model is proposed to explain a shift towards intracortical inputs.
对痉挛性双侧瘫患者和年龄匹配的对照组进行了功能连接性（功能磁共振成像）分析。计算了选定种子区域（sROI）静息状态下的自发活动与全脑每个体素之间的皮尔逊相关性（r值）。种子ROI以体感和顶叶背侧注意区域中第二指尖触觉刺激激活的焦点为中心。双侧瘫组显示躯体运动区的网络显著扩展，但背侧注意区没有。尽管在指尖焦点处有一个sROI，但这些扩展的网络几乎覆盖了体感和运动区域的所有拓扑表征。双侧瘫组功能磁共振成像改变以及痉挛性双侧瘫普遍存在的感觉运动缺陷的一个可能潜在原因是，产前晚期白质损伤导致板下神经元局部损伤。我们假设，在痉挛性双侧瘫中，通过与减少或缺失的丘脑皮质输入成功竞争，皮质内连接变得占主导地位。类似于板下消融对眼优势柱的影响（卡诺尔德和沙茨，《神经元》，2006年；51:627 - 638），提出了一种尖峰时间依赖性可塑性模型来解释向皮质内输入的转变。
