Mammals are born on a precocial-altricial continuum. Altricial species produce helpless neonates with closed distant organs that are incapable of locomotion, whereas precocial species give birth to well-developed young that possess sophisticated sensory and locomotor capabilities. Previous studies suggest that distinct patterns of cortex development differ between precocial and altricial species. This study compares patterns of neocortex neurogenesis and maturation in the precocial guinea pig and altricial dwarf rabbit, both belonging to the taxon of Glires. We show that the principle order of neurodevelopmental events is preserved in the neocortex of both species. Moreover, we show that neurogenesis starts at a later postconceptional day and takes longer in absolute gestational days in the precocial than altricial neocortex. Intriguingly, our data indicate that the dwarf rabbit neocortex contains a higher abundance of highly proliferative basal progenitors than the guinea pig, which might underlie its higher encephalization quotient, demonstrating that the amount of neuron production is determined by a complex regulation of multiple factors. Furthermore, we show that the guinea pig neocortex exhibits a higher maturation status at birth, thus providing evidence for the notions that precocial species might have acquired the morphological machineries required to attain their high functional state at birth and that brain expansion in precocial newborn is largely due to prenatally initiating processes of gliogenesis and neuron differentiation instead of increased neurogenesis. Together, this study reveals important insights into the timing and cellular differences that regulate mammalian brain growth and maturation and provides a better understanding of the evolution of mammalian altriciality and presociality.

中文翻译：

---

矮人兔和早熟豚鼠新皮层神经发生和成熟的发育差异

哺乳动物出生于社会前的连续体。极乐的物种会产生无助的新生儿，这些器官具有无法运动的封闭的远处器官，而早熟的物种会生出发育成熟的年轻人，这些人具有复杂的感觉和运动能力。先前的研究表明，早熟和早熟物种的皮层发育的不同模式是不同的。这项研究比较了早熟豚鼠和矮小兔的新皮层神经发生和成熟的模式，这两种动物均属于格里里斯的分类群。我们表明，神经发育事件的原理顺序被保留在两个物种的新皮层中。而且，我们显示神经发生在受孕后的较晚一天开始，并且在早孕的绝对妊娠天比神经新皮层需要更长的时间。有趣的是 我们的数据表明，侏儒兔新皮层比豚鼠具有更高的高度增殖性基础祖细胞，这可能是其较高的脑电商的基础，这表明神经元的产生量是由多种因素的复杂调控决定的。此外，我们显示豚鼠新皮质在出生时表现出较高的成熟状态，从而为以下观念提供了证据：前社会物种可能已获得了在出生时达到其高功能状态所需的形态学机制，并且前社会新生儿的大脑扩张在很大程度上归因于胶质增生和神经元分化的产前启动过程，而不是神经发生的增加。一起，