生物谷报道:美国约翰·霍普金斯大学医学院华裔科学家Hongjun Song领导的研究小组发现,成年大鼠新生神经元具有与幼鼠相近的可塑性。相关论文发表在5月24日的《神经元》(Neuron)杂志上。
过去的行为研究表明,成年大鼠新产生的神经元大约需要1到3周的时间才能融入现存的神经网络,但是此次研究结果显示,神经元的成熟期实际上可能长达4到6周。
Song等人检测了成年大鼠海马区新产生的齿状回神经元的电生理学特征,结果他们吃惊地发现,成年大鼠新生神经元可塑性的变化模式与新生小鼠非常相似。
该项研究表明,新生神经元比成熟神经元在形成记忆方面的作用更大,这印证了之前成年大鼠利用新生神经元完成空间记忆任务的研究结果。
下一步科学家们将着手研究新生神经元的特殊性质,以及他们在大脑中的特殊地位。如果科学家们能够发现年轻细胞的分子机制,将向利用干细胞修复大脑损伤迈出重要的一步。
原始出处:
Neuron, Vol 54, 559-566, 24 May 2007
Article
A Critical Period for Enhanced Synaptic Plasticity in Newly Generated Neurons of the Adult Brain
Shaoyu Ge,1,2,3 Chih-hao Yang,1,2,4 Kuei-sen Hsu,4 Guo-li Ming,1,2,3 and Hongjun Song1,2,3,
1 Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
3 The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
4 Department of Pharmacology, College of Medicine, National Cheng Kung University, No. 1, University Road, Tainan City 701, Taiwan
Corresponding author
Hongjun Song
shongju1@jhmi.edu
Summary
Active adult neurogenesis occurs in discrete brain regions of all mammals and is widely regarded as a neuronal replacement mechanism. Whether adult-born neurons make unique contributions to brain functions is largely unknown. Here we systematically characterized synaptic plasticity of retrovirally labeled adult-born dentate granule cells at different stages during their neuronal maturation. We identified a critical period between 1 and 1.5 months of the cell age when adult-born neurons exhibit enhanced long-term potentiation with increased potentiation amplitude and decreased induction threshold. Furthermore, such enhanced plasticity in adult-born neurons depends on developmentally regulated synaptic expression of NR2B-containing NMDA receptors. Our study demonstrates that adult-born neurons exhibit the same classic critical period plasticity as neurons in the developing nervous system. The transient nature of such enhanced plasticity may provide a fundamental mechanism allowing adult-born neurons within the critical period to serve as major mediators of experience-induced plasticity while maintaining stability of the mature circuitry.