Hurlbert R J, Koyanagi I, Tator C H
Division of Neurosurgery, Toronto Hospital, University of Toronto, Ontario, Canada.
J Neurotrauma. 1993 Summer;10(2):181-200. doi: 10.1089/neu.1993.10.181.
The purpose of this study was to evaluate two types of ascending sensory evoked potentials (SEPs) in the rat and their capacity for selective monitoring of dorsal versus ventral spinal cord integrity. SEPs were elicited by direct sciatic nerve stimulation. A cerebellar evoked response was recorded over the paramedian lobule of the cerebellar hemisphere (CEPpml) while somatosensory evoked potentials (SSEPs) were simultaneously recorded over the sensorimotor cortex. All components of the CEPpml and SSEP except the longest latency positive waves were present in each animal. At stimulus intensities of 3 to 10 mA, no significant changes in latency of the peaks were observed, but amplitudes of the longer latency responses tended to increase throughout this stimulation range. Unilateral sciatic stimulation resulted in bilateral cortical responses, larger ipsilaterally for the CEPpml, and contralaterally for the SSEP. Selective spinal cord lesions demonstrated N9 and P14 of the CEPpml to be mediated primarily through the ventral spinal cord, while P14 and N19 of the SSEP were conducted primarily through the dorsal columns. Sectioning of the cerebellar peduncles abolished N9 and P14 of the CEPpml despite persistence of the SSEP. This study demonstrates that selective assessment of the ventral and dorsal spinal cord is possible in the rat by monitoring SEPs.
本研究的目的是评估大鼠的两种上行感觉诱发电位（SEP）及其对脊髓背侧与腹侧完整性进行选择性监测的能力。SEP由直接刺激坐骨神经引出。在小脑半球旁正中小叶记录小脑诱发电位（CEPpml），同时在感觉运动皮层记录体感诱发电位（SSEP）。每只动物均出现CEPpml和SSEP除最长潜伏期正波外的所有成分。在3至10 mA的刺激强度下，各波峰潜伏期无显著变化，但在此刺激范围内，较长潜伏期反应的波幅有增加趋势。单侧坐骨神经刺激导致双侧皮层反应，CEPpml同侧反应较大，SSEP对侧反应较大。选择性脊髓损伤表明，CEPpml的N9和P14主要通过脊髓腹侧传导，而SSEP的P14和N19主要通过背柱传导。切断小脑脚后，尽管SSEP持续存在，但CEPpml的N9和P14消失。本研究表明，通过监测SEP可对大鼠脊髓腹侧和背侧进行选择性评估。
