Department of Medicine, Unit of Physiology, University of Fribourg, Fribourg, Switzerland.
Eur J Neurosci. 2010 Jan;31(2):273-85. doi: 10.1111/j.1460-9568.2009.07061.x. Epub 2010 Jan 13.
The dentate gyrus is one of only two regions of the mammalian brain where substantial neurogenesis occurs postnatally. However, detailed quantitative information about the postnatal structural maturation of the primate dentate gyrus is meager. We performed design-based, stereological studies of neuron number and size, and volume of the dentate gyrus layers in rhesus macaque monkeys (Macaca mulatta) of different postnatal ages. We found that about 40% of the total number of granule cells observed in mature 5-10-year-old macaque monkeys are added to the granule cell layer postnatally; 25% of these neurons are added within the first three postnatal months. Accordingly, cell proliferation and neurogenesis within the dentate gyrus peak within the first 3 months after birth and remain at an intermediate level between 3 months and at least 1 year of age. Although granule cell bodies undergo their largest increase in size during the first year of life, cell size and the volume of the three layers of the dentate gyrus (i.e. the molecular, granule cell and polymorphic layers) continue to increase beyond 1 year of age. Moreover, the different layers of the dentate gyrus exhibit distinct volumetric changes during postnatal development. Finally, we observe significant levels of cell proliferation, neurogenesis and cell death in the context of an overall stable number of granule cells in mature 5-10-year-old monkeys. These data identify an extended developmental period during which neurogenesis might be modulated to significantly impact the structure and function of the dentate gyrus in adulthood.
齿状回是哺乳动物大脑中仅有的两个在出生后发生大量神经发生的区域之一。然而，关于灵长类动物齿状回出生后结构成熟的详细定量信息却很少。我们对不同出生后年龄的恒河猴（Macaca mulatta）齿状回的神经元数量和大小以及齿状回各层体积进行了基于设计的体视学研究。我们发现，在成熟的 5-10 岁猕猴中观察到的颗粒细胞总数的约 40%是在出生后添加到颗粒细胞层中的；其中 25%的神经元是在出生后前三个月添加的。因此，齿状回内的细胞增殖和神经发生在出生后前 3 个月达到高峰，并在 3 个月至至少 1 岁之间保持在中间水平。虽然颗粒细胞体在生命的第一年中经历了最大的大小增加，但细胞大小和齿状回的三个层（即分子层、颗粒细胞层和多形细胞层）的体积在 1 岁以后仍继续增加。此外，齿状回的不同层在出生后发育过程中表现出不同的体积变化。最后，我们在成熟的 5-10 岁猴子中观察到整体稳定的颗粒细胞数量下存在显著的细胞增殖、神经发生和细胞死亡水平。这些数据确定了一个延长的发育时期，在此期间神经发生可能会受到调节，从而对成年期齿状回的结构和功能产生重大影响。
