Department of Medical Neuroscience, Graduate School of Medical Sciences, Kanazawa University, Takara-machi 13-1, Kanazawa, Ishikawa, 920-8640, Japan.
Mol Brain. 2020 Mar 10;13(1):37. doi: 10.1186/s13041-020-00575-8.
In the white matter of the human cerebrum, the majority of cortico-cortical fibers are of short range, connecting neighboring cortical areas. U-fibers represent connections between neighboring areas and are located in the white matter immediately deep to the cerebral cortex. Using gyrencephalic carnivore ferrets, here we investigated the neurochemical, anatomical and developmental features of U-fibers. We demonstrate that U-fibers were derived from neighboring cortical areas in ferrets. U-fiber regions in ferrets were intensely stained with Gallyas myelin staining and Turnbull blue iron staining. We further found that U-fibers were derived from neurons in both upper and lower layers in neighboring areas of the cerebral cortex and that U-fibers were formed later than axons in the deep white matter during development. Our findings shed light on the fundamental features of U-fibers in the gyrencephalic cerebral cortex. Because genetic manipulation techniques for ferrets are now available, ferrets should be an important option for investigating the development, functions and pathophysiological changes of U-fibers.
在人类大脑的白质中，大多数皮质-皮质纤维是短程的，连接相邻的皮质区域。U 型纤维代表相邻区域之间的连接，位于大脑皮层深部的白质中。利用脑回化的食肉目雪貂，我们在此研究了 U 型纤维的神经化学、解剖学和发育特征。我们证明 U 型纤维来源于雪貂的相邻皮质区域。U 纤维区域在雪貂中经 Gallyas 髓鞘染色和 Turnbull 蓝色铁染色后呈现强烈染色。我们进一步发现，U 纤维来源于相邻大脑皮质区域上下层的神经元，并且在发育过程中，U 纤维比深部白质中的轴突形成得晚。我们的研究结果揭示了脑回化大脑皮质中 U 纤维的基本特征。由于现在有用于雪貂的基因操作技术，雪貂应该是研究 U 纤维的发育、功能和病理生理变化的重要选择。
