Hans-Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany.
Department of Psychology, Technische Universität Dresden, 01187 Dresden, Germany.
Cell Rep. 2019 Mar 19;26(12):3173-3182.e5. doi: 10.1016/j.celrep.2019.02.061.
Synchronized activity is a universal characteristic of immature neural circuits that is essential for their developmental refinement and strongly depends on GABAergic neurotransmission. A major subpopulation of GABA-releasing interneurons (INs) expresses somatostatin (SOM) and proved critical for rhythm generation in adulthood. Here, we report a mechanism whereby SOM INs promote neuronal synchrony in the neonatal CA1 region. Combining imaging and electrophysiological approaches, we demonstrate that SOM INs and pyramidal cells (PCs) coactivate during spontaneous activity. Bidirectional optogenetic manipulations reveal excitatory GABAergic outputs to PCs that evoke correlated network events in an NKCC1-dependent manner and contribute to spontaneous synchrony. Using a dynamic systems modeling approach, we show that SOM INs affect network dynamics through a modulation of network instability and amplification threshold. Our study identifies a network function of SOM INs with implications for the activity-dependent construction of developing brain circuits.
同步活动是未成熟神经回路的普遍特征，对其发育细化至关重要，并且强烈依赖 GABA 能神经传递。释放 GABA 的中间神经元 (INs) 的一个主要亚群表达生长抑素 (SOM)，并被证明对成年期的节律产生至关重要。在这里，我们报告了 SOM INs 在新生 CA1 区促进神经元同步的机制。结合成像和电生理方法，我们证明 SOM INs 和锥体细胞 (PCs) 在自发活动期间共同激活。双向光遗传学操作显示，SOM INs 对 PCs 产生兴奋性 GABA 能输出，以 NKCC1 依赖的方式引发相关的网络事件，并有助于自发同步。使用动态系统建模方法，我们表明 SOM INs 通过调节网络不稳定性和放大阈值来影响网络动力学。我们的研究确定了 SOM INs 的网络功能，这对发育中大脑回路的活动依赖性构建具有重要意义。
