Mitz A R, Humphrey D R
Neurosci Lett. 1986 Feb 14;64(1):59-64. doi: 10.1016/0304-3940(86)90663-4.
In order to examine, separately, the organizations of pyramidal and extrapyramidal projections from the primary motor cortex, efforts were made to map the forelimb area of two rhesus monkeys with microstimulation before and after unilateral pyramidotomy. However, microstimulation was not effective in evoking motor responses following complete pyramidal tract section. Movements were evoked using a modified intracortical electrode with a large exposed tip and using stimulation parameters similar to those used for surface stimulation. The results from this modified intracortical stimulation generally agree with those from surface stimulation studies in that: (1) the extrapyramidal topography is similar to the normal motor cortex topography and (2) while peripheral responses can be evoked from the cortex following pyramidotomy, greater spatial and temporal summation are necessary to evoke these responses. In addition, the modified intracortical technique revealed a more widespread post-pyramidotomy digit representation than observed previously with surface stimulation. Results from an incomplete pyramidal tract lesion suggest that recovery of motor function may include plastic changes in surviving corticospinal axons.
为了分别研究初级运动皮层的锥体和锥体外投射组织，我们在单侧锥体切断术前和术后，通过微刺激对两只恒河猴的前肢区域进行了图谱绘制。然而，在完全切断锥体束后，微刺激未能有效诱发运动反应。使用一种尖端暴露较大的改良皮质内电极，并采用与表面刺激相似的刺激参数来诱发运动。这种改良皮质内刺激的结果与表面刺激研究的结果总体一致，即：（1）锥体外地形图与正常运动皮层地形图相似；（2）虽然在锥体切断术后可从皮层诱发外周反应，但需要更大的空间和时间总和来诱发这些反应。此外，改良皮质内技术显示，与之前表面刺激观察到的情况相比，锥体切断术后手指的表征范围更广。不完全锥体束损伤的结果表明，运动功能的恢复可能包括存活的皮质脊髓轴突的可塑性变化。
