Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano (TO), and Department of Veterinary Morphophysiology, University of Turin, Turin, Italy.
Prog Neurobiol. 2012 Jul;98(1):1-15. doi: 10.1016/j.pneurobio.2012.05.002. Epub 2012 May 17.
The mammalian central nervous system, due to its interaction with the environment, must be endowed with plasticity. Conversely, the nervous tissue must be substantially static to ensure connectional invariability. Structural plasticity can be viewed as a compromise between these requirements. In adult mammals, brain structural plasticity is strongly reduced with respect to other animal groups in the phylogenetic tree. It persists under different forms, which mainly consist of remodeling of neuronal shape and connectivity, and, to a lesser extent, the production of new neurons. Adult neurogenesis is mainly restricted within two neurogenic niches, yet some gliogenic and neurogenic processes also occur in the so-called non-neurogenic tissue, starting from parenchymal progenitors. In this review we focus on a population of immature, non-newly generated neurons in layer II of the cerebral cortex, which were previously thought to be newly generated since they heavily express the polysialylated form of the neural cell adhesion molecule and doublecortin. These unusual neurons exhibit characteristics defining an additional type of structural plasticity, different from either synaptic plasticity or adult neurogenesis. Evidences concerning their morphology, antigenic features, ultrastructure, phenotype, origin, fate, and reaction to different kind of stimulations are gathered and analyzed. Their possible role is discussed in the context of an enriched complexity and heterogeneity of mammalian brain structural plasticity.
哺乳动物中枢神经系统由于与环境的相互作用，必须具有可塑性。相反，神经组织必须在很大程度上保持静态，以确保连接的不变性。结构可塑性可以被视为这些要求之间的妥协。在成年哺乳动物中，与系统发生树上的其他动物群体相比，大脑结构的可塑性大大降低。它以不同的形式存在，主要包括神经元形状和连接的重塑，以及在较小程度上产生新的神经元。成年神经发生主要局限于两个神经发生龛内，但一些神经胶质发生和神经发生过程也发生在所谓的非神经发生组织中，起始于实质祖细胞。在这篇综述中，我们重点关注大脑皮层 II 层中一群不成熟的、非新生成的神经元，它们以前被认为是新生成的，因为它们强烈表达神经细胞粘附分子的多涎酸化形式和双皮质蛋白。这些不寻常的神经元表现出定义另一种结构可塑性的特征，与突触可塑性或成年神经发生不同。收集和分析了关于它们的形态、抗原特征、超微结构、表型、起源、命运以及对不同刺激的反应的证据。讨论了它们在哺乳动物大脑结构可塑性的丰富复杂性和异质性背景下的可能作用。
