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为了了解外周神经损伤对体感皮层分域组构的影响,在成年大鼠上观察了切断坐骨神经(SC)前、即刻和切断后数周内后爪皮层代表区的改变。在盐酸氯胺酮麻醉下,用微电极记录后爪皮肤轻触刺激在对侧体感皮层工区诱发的多单位反应,得出后爪的皮层代表区图。在16例中,8例大鼠观察了切断SC的即时效应。结果表明,不但SC代表区丧失皮肤反应性,原隐神经(SA)代表区的皮肤反应性也明显下降或消失,同时神经元自发活动也明显减弱。另8例大鼠在切断后数周内做了1～3次重复测定。在最初几天,原SA代表区范围内多数记录点的皮肤反应性仍未恢复,但在原SC代表区内,一些记录点转而对SA皮肤轻触刺激起反应。在随后数周内SA代表区进行性地扩张,占领了大部分原SC代表区。这一结果说明成年大鼠外周神经损伤可导致体感皮层发生显著的重组改变。
In order to understand the effect of peripheral nerve injury on the subfield organization of somatosensory cortex, the changes of the representative area of the hind paw cortex were observed in adult rats before sciatic nerve (SC), immediately and within several weeks after cutting off. Under ketamine hydrochloride anesthesia, the multi-unit response induced by the hind paw skin stimulation with the microelectrode was recorded in the contralateral somatosensory cortex and the cortical representation of the hind paw was obtained. In 16 cases, 8 rats observed the immediate effect of cutting SC. The results showed that not only the area of skin degeneration in SC was lost, but also the skin reactivity in the area of saphenous nerve (SA) was significantly decreased or disappeared. At the same time, the spontaneous activity of neurons was significantly weakened. The other 8 rats were subjected to 1 to 3 repeated determinations within a few weeks after cutting off. In the first few days, skin reactivity at most sites in the original SA area remained undetected, but some of the recording sites in the original SC area turned in response to SA skin tactile stimuli. During the following weeks, the SA representative area was expanded in a constructive manner, occupying most of the original SC representative area. This result shows that adult rat peripheral nerve injury can lead to significant changes in the somatic cortex restructuring.