In sub-mammalian vertebrates like fishes, amphibians, and reptiles, new neurons are produced during the entire lifespan. This capacity diminishes considerably in birds and even more in mammals where it persists only in the olfactory system and hippocampal dentate gyrus. Adult neurogenesis declines even more drastically in nonhuman primates and recent evidence shows that this is basically extinct in humans. Why should such seemingly useful capacity diminish during primate evolution? It has been proposed that this occurs because of the need to retain acquired complex knowledge in stable populations of neurons and their synaptic connections during many decades of human life. In this review, we will assess critically the claim of significant adult neurogenesis in humans and show how current evidence strongly indicates that humans lack this trait. In addition, we will discuss the allegation of many rodent studies that adult neurogenesis is involved in psychiatric diseases and that it is a potential mechanism for human neuron replacement and regeneration. We argue that these reports, which usually neglect significant structural and functional species-specific differences, mislead the general population into believing that there might be a cure for a variety of neuropsychiatric diseases as well as stroke and brain trauma by genesis of new neurons and their incorporation into existing synaptic circuitry.

在鱼类、两栖动物和爬行动物等亚哺乳动物脊椎动物中，在整个生命周期中都会产生新的神经元。这种能力在鸟类中大大减弱，在哺乳动物中更是如此，它只存在于嗅觉系统和海马齿状回中。在非人类灵长类动物中，成年神经发生的下降甚至更为剧烈，最近的证据表明，这在人类中基本上已经灭绝。为什么这种看似有用的能力会在灵长类动物进化过程中减少？有人提出，这是因为在人类生命的几十年中，需要在稳定的神经元群及其突触连接中保留获得的复杂知识。在这篇综述中，我们将批判性地评估人类重要的成人神经发生的说法，并展示当前的证据如何有力地表明人类缺乏这种特征。此外，我们将讨论许多啮齿动物研究的指控，即成年神经发生与精神疾病有关，并且它是人类神经元替代和再生的潜在机制。我们争辩说，这些报告通常忽略了显着的结构和功能的物种特异性差异，误导普通民众相信可以通过新神经元的起源及其它们的产生来治愈各种神经精神疾病以及中风和脑外伤。并入现有的突触电路。