Although it has been believed that the evolution of cortical folds was a milestone, allowing for an increase in the number of neurons in the cerebral cortex, the mechanisms underlying the formation of cortical folds are largely unknown. Here we show regional differences in the expression of fibroblast growth factor receptors (FGFRs) in the developing cerebral cortex of ferrets even before cortical folds are formed. By taking the advantage of our in utero electroporation technique for ferrets, we found that cortical folding was impaired in the ferret cerebral cortex when FGF signaling was inhibited. We also found that FGF signaling was crucial for producing Pax6-positive neural progenitors in the outer subventricular zone (OSVZ) of the developing cerebral cortex. Furthermore, we found that upper layers of the cerebral cortex were preferentially reduced by inhibiting FGF signaling. Our results shed light on the mechanisms of cortical folding in gyrencephalic mammalian brains.

中文翻译：

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大脑皮层的旋转需要哺乳动物大脑中的 FGF 信号传导

尽管人们认为皮质褶皱的进化是一个里程碑，允许大脑皮层中神经元数量的增加，但皮质褶皱形成的潜在机制在很大程度上是未知的。在这里，我们显示了雪貂发育中的大脑皮层中成纤维细胞生长因子受体 (FGFR) 表达的区域差异，甚至在形成皮层褶皱之前。通过利用我们对雪貂的子宫内电穿孔技术，我们发现当 FGF 信号传导受到抑制时，雪貂大脑皮层的皮质折叠受损。我们还发现 FGF 信号对于在发育中的大脑皮层的外脑室下区 (OSVZ) 中产生 Pax6 阳性神经祖细胞至关重要。此外，我们发现通过抑制 FGF 信号，大脑皮层的上层优先减少。我们的结果阐明了回脑哺乳动物大脑中皮质折叠的机制。