Departments of Biology, Psychology, and Otolaryngology, and Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195.
Proc Natl Acad Sci U S A. 2013 Oct 8;110(41):16640-4. doi: 10.1073/pnas.1310237110. Epub 2013 Sep 23.
A striking feature of the nervous system is that it shows extensive plasticity of structure and function that allows animals to adjust to changes in their environment. Neural activity plays a key role in mediating experience-dependent neural plasticity and, thus, creates a link between the external environment, the nervous system, and behavior. One dramatic example of neural plasticity is ongoing neurogenesis in the adult brain. The role of neural activity in modulating neuronal addition, however, has not been well studied at the level of neural circuits. The avian song control system allows us to investigate how activity influences neuronal addition to a neural circuit that regulates song, a learned sensorimotor social behavior. In adult white-crowned sparrows, new neurons are added continually to the song nucleus HVC (proper name) and project their axons to its target nucleus, the robust nucleus of the arcopallium (RA). We report here that electrical activity in RA regulates neuronal addition to HVC. Decreasing neural activity in RA by intracerebral infusion of the GABAA receptor agonist muscimol decreased the number of new HVC neurons by 56%. Our results suggest that postsynaptic electrical activity influences the addition of new neurons into a functional neural circuit in adult birds.
神经系统的一个显著特点是其具有广泛的结构和功能可塑性，使动物能够适应环境的变化。神经活动在介导经验依赖性神经可塑性方面起着关键作用，从而在外部环境、神经系统和行为之间建立了联系。神经可塑性的一个显著例子是成年大脑中的持续神经发生。然而，神经活动在调节神经元添加方面的作用在神经回路水平上尚未得到很好的研究。鸟类歌唱控制系统使我们能够研究活动如何影响调节歌唱的神经回路中的神经元添加，歌唱是一种习得的感觉运动社交行为。在成年白头翁中，新的神经元不断地添加到歌唱核 HVC（学名）中，并将其轴突投射到其靶核，即强大的弓状核（RA）。我们在这里报告说，RA 中的电活动调节 HVC 中的神经元添加。通过脑内输注 GABAA 受体激动剂 muscimol 降低 RA 中的神经活动，使新的 HVC 神经元数量减少了 56%。我们的结果表明，突触后电活动影响成年鸟类中功能性神经回路中新神经元的添加。
