Stanfield B B, O'Leary D D
Nature. 1985;313(5998):135-7. doi: 10.1038/313135a0.
In adult rats, cortical neurones that send axons through the pyramidal tract are confined to layer V, over the rostral two-thirds of the cerebral hemisphere. However, during the first postnatal week, many neurones in layer V in the occipital cortex (including the visual cortex) also extend axon collaterals through the pyramidal tract and into the spinal cord. These occipital corticospinal collaterals are completely eliminated over the subsequent 2 weeks, although their cells of origin do not die. We now report that when portions of the occipital cortex from fetal rats are transplanted to more rostral cortical regions of newborn rats, some of the transplanted neurones not only extend axons through the pyramidal tract, but also maintain these axons beyond the stage at which they are normally eliminated. These results suggest that normally-eliminated cortical axons can be 'rescued' and, in the case of pyramidal tract neurones, the position of the neurones within the tangential plane of the cortex is a critical factor in determining which neurones retain and which lose their pyramidal tract collaterals.
在成年大鼠中，其轴突通过锥体束的皮质神经元局限于大脑半球前三分之二区域的V层。然而，在出生后的第一周，枕叶皮质（包括视觉皮质）V层中的许多神经元也通过锥体束将轴突侧支延伸至脊髓。尽管这些枕叶皮质脊髓侧支的起源细胞并未死亡，但在随后的两周内它们会完全消失。我们现在报告，当将胎鼠枕叶皮质的部分组织移植到新生大鼠更靠前的皮质区域时，一些移植的神经元不仅通过锥体束延伸轴突，而且在这些轴突正常被消除的阶段之后仍能维持。这些结果表明，正常情况下被消除的皮质轴突可以被“拯救”，对于锥体束神经元而言，神经元在皮质切线平面内的位置是决定哪些神经元保留其锥体束侧支而哪些神经元失去这些侧支的关键因素。
