运动诱发电位与体感诱发电位的脊髓等电位图的实验研究

Isopotential map of somatosensory evoked potential and motor evoked potential in spinal cord:an experimental study

目的 研究体感诱发电位 (SEP)和运动诱发电位 (MEP)在脊髓横断面上传导通路的分布特点。为临床上应用复合脊髓诱发电位 ,提高监护水平提供实验依据。方法 分别刺激Wistar大鼠的皮质感觉运动区和坐骨神经 ,用微电极在大鼠腰膨大记录SEP和MEP。采用不同刺激强度、频率观察它们对SEP和MEP的影响。在此基础上 ,在半侧脊髓上分 4 0～ 6 0个点记录每点的SEP和MEP。根据SEP和MEP的波幅变化 ,制作大鼠腰膨大部位的等电位图。结果 ( 1)SEP的N1 P1波幅从脊髓腹侧至背侧逐渐增加 ,中央较外侧部显著 ,差异有显著性 (P <0 0 5 )。 ( 2 )MEP的N2 P2的波幅从腹侧至背侧逐渐下降 ,中央较外侧明显 ,差异有显著性 (P <0 0 5 )。结论 ( 1)证实了大鼠的SEP主要传导通路分布于后索 ,大鼠的MEP传导通路主要分布于前索。二者在脊髓横断面上各自有明显的代表区域 ,可以涵盖脊髓横断面的主要部分。 ( 2 )大鼠MEP的兴奋起源可能是锥体外系。

Objective To investigate the distribution of conduction pathways of somtosensory evoked potential (SEP) and motor evoked potential (MEP) in the spinal cord. Methods Twenty five Wistar rats underwent operation to expose the left sciatic nerve and sphenotresia. The sciatic nerve and sensory motor cortex of 10 rats were stimulated so as to induce MEP and SEP. Different stimulating parameters were used to record their influence on MEP and SEP. Then the microelectrode was removed to a new place 1 cm from the original place and the maximum MEP and maximum SEP were recorded so as to calculate the conduction speeds of MEP and SEP. A microelectrode was put to the ventral side of spinal cord of 15 rats so as to record the isopotential map of MEP and SEP in the spinal cord. Results The Ni P1 of SEP increased when the microelectrode was moved from the anterior side to the posterior side and the change was more prominent in the anterior funiculus area. The N2 P2 decreased when the microelectrode was moved from anterior side to posterior side, and the change was more prominent in the posterior funiculus area. Conclusion SEP is mainly conducted in the posterior tracts and MEP in the anterior tracts. MEP may originate from extra pyramid system.