An Lingling, Tang Yuanhong, Wang Doudou, Jia Shanshan, Pei Qingqi, Wang Quan, Yu Zhaofei, Liu Jian K
School of Computer Science and Technology, Xidian University, Xi'an, China.
National Engineering Laboratory for Video Technology, Department of Computer Science and Technology, Peking University, Beijing, China.
Front Comput Neurosci. 2020 Apr 21;14:26. doi: 10.3389/fncom.2020.00026. eCollection 2020.
The majority of neurons in the neuronal system of the brain have a complex morphological structure, which diversifies the dynamics of neurons. In the granular layer of the cerebellum, there exists a unique cell type, the unipolar brush cell (UBC), that serves as an important relay cell for transferring information from outside mossy fibers to downstream granule cells. The distinguishing feature of the UBC is that it has a simple morphology, with only one short dendritic brush connected to its soma. Based on experimental evidence showing that UBCs exhibit a variety of dynamic behaviors, here we develop two simple models, one with a few detailed ion channels for simulation and the other one as a two-variable dynamical system for theoretical analysis, to characterize the intrinsic dynamics of UBCs. The reasonable values of the key channel parameters of the models can be determined by analysis of the stability of the resting membrane potential and the rebound firing properties of UBCs. Considered together with a large variety of synaptic dynamics installed on UBCs, we show that the simple-structured UBCs, as relay cells, can extend the range of dynamics and information from input mossy fibers to granule cells with low-frequency resonance and transfer stereotyped inputs to diverse amplitudes and phases of the output for downstream granule cells. These results suggest that neuronal computation, embedded within intrinsic ion channels and the diverse synaptic properties of single neurons without sophisticated morphology, can shape a large variety of dynamic behaviors to enhance the computational ability of local neuronal circuits.
大脑神经元系统中的大多数神经元具有复杂的形态结构，这使神经元的动态特性多样化。在小脑颗粒层中，存在一种独特的细胞类型，即单极刷状细胞（UBC），它作为重要的中继细胞，用于将来自苔藓纤维外部的信息传递给下游颗粒细胞。UBC的显著特征是其形态简单，只有一个短的树突刷连接到其胞体。基于表明UBC表现出多种动态行为的实验证据，我们在此开发了两个简单模型，一个带有一些用于模拟的详细离子通道，另一个作为用于理论分析的双变量动态系统，以表征UBC的内在动态特性。模型关键通道参数的合理值可以通过分析静息膜电位的稳定性和UBC的反弹放电特性来确定。结合安装在UBC上的多种突触动态特性，我们表明，作为中继细胞的结构简单的UBC可以通过低频共振扩展从输入苔藓纤维到颗粒细胞的动态范围和信息，并将定型输入转换为下游颗粒细胞输出的不同幅度和相位。这些结果表明，嵌入在内在离子通道和单个神经元的多种突触特性中而无需复杂形态的神经元计算，可以塑造多种动态行为，以增强局部神经元回路的计算能力。
