Lotze M, Laubis-Herrmann U, Topka H
Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany.
Restor Neurol Neurosci. 2006;24(2):97-107.
After a spinal cord injury (SCI), which was complete, deafferentation of the body representation caudal to the lesion height results in drastic changes in the cortical representation. The underlaying processes are poorly understood.
We investigated cortical representation sites of upper limb muscles using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) in five patients suffering from thoracic complete SCI and one with an incomplete SCI in the height of L1.
In comparison to healthy controls fMRI demonstrated a displacement of elbow movement representations in the precentral gyrus in patients with complete SCI into the direction of the deafferented cortical thoracic representation. Changes increased with time after the incidence of SCI. TMS revealed reduced excitability and prolonged silent periods for muscles more distant to the deafferented area.
Whereas fMRI demonstrated changes in representation sites adjacent to the deafferented area, TMS excitability changes were also observed more distant to the deafferented area and silent periods were prolonged in comparison to healthy controls. TMS changes might depend on both: the distance to the deafferented area and the time of persistence of deafferentation.
在脊髓损伤（SCI）完全性损伤后，损伤平面以下身体代表区的传入神经阻滞会导致皮质代表区发生剧烈变化。其潜在机制尚不清楚。
我们使用功能磁共振成像（fMRI）和经颅磁刺激（TMS），对5例患有胸段完全性SCI和1例L1水平不完全性SCI的患者的上肢肌肉皮质代表区进行了研究。
与健康对照相比，fMRI显示完全性SCI患者中央前回中肘部运动代表区向失传入皮质胸段代表区方向移位。这些变化随着SCI发生后的时间而增加。TMS显示，离失传入区域较远的肌肉兴奋性降低，静息期延长。
fMRI显示失传入区域附近的代表区发生了变化，而TMS兴奋性变化在离失传入区域较远的地方也有观察到，并且与健康对照相比静息期延长。TMS变化可能取决于两个因素：与失传入区域的距离以及失传入持续的时间。
