Spiking and nonspiking models of starburst amacrine cells in the rabbit retina.
Spiking and nonspiking models of starburst amacrine cells in the rabbit retina.
复制标题
兔视网膜星爆无长突细胞的尖峰和非尖峰模型。
DOI：
10.1017/s0952523800011780
复制
发表时间：
1997
影响因子：
1.9
通讯作者：
Miller,RF
中科院分区：
文献类型：
--
作者：
Velte,TJ;Miller,RF
采用区室模型和计算机模拟技术研究了兔视网膜星爆无长突细胞的综合特性。这些模拟的解剖学基础是由细胞内染色的星爆无长突细胞的计算机重建以及已发表的树突直径和生物物理特性的数据提供的。包括被动和主动膜属性来模拟尖峰和非尖峰行为。进入一个或多个区室的模拟突触输入由类似双极的电导变化组成，其峰值和稳态分量由两个高斯响应之和提供。模拟脉冲生成是通过使用包含五个非线性通道（INa、ICa、Ia、.Ik.Ik.Ca）的脉冲生成模型来实现的。改变钠通道电导变化的幅度以满足几种不同类型的脉冲产生和传播行为。我们研究了一系列模型约束，其中包括膜电阻 (Rm) 从 4,000 Ω.cm2 到 100,000 Ω.cm2 的变化，以及枝晶直径从 0.1 到 0.3 μm 的变化。在一系列单独的模拟中，我们基于有或没有树突和体细胞尖峰行为的模型，研究了使用体体应用的单电极电压钳对星爆无长突细胞进行电压钳位的可行性。我们的模拟研究表明，当 Rm 高时，星爆无长突细胞的单个树突可以充当独立的功能亚基，前提是一个或少量树突被突触共激活。然而，随着共激活树突数量的增加，星爆细胞行为变得更加均匀，独立的树突功能不再普遍。树突中脉冲活动的存在提出了有关树突功能的新问题。然而，树突脉冲不一定消除独立的树突功能，因为树突脉冲在向体细胞传播时通常会失败，在体细胞中它们会贡献与传统突触电流相加的 EPSP 样反应。
The integrative properties of starburst amacrine cells in the rabbit retina were studied with compartmental models and computer-simulation techniques. The anatomical basis for these simulations was provided by computer reconstructions of intracellularly stained starburst amacrine cells and published data on dendritic diameter and biophysical properties. Passive and active membrane properties were included to simulate spiking and nonspiking behavior. Simulated synaptic inputs into one or more compartments consisted of a bipolar-like conductance change with peak and steady-state components provided by the sum of two Gaussian responses. Simulated impulse generation was achieved by using a model of impulse generation that included five nonlinear channels (INa, ICa, Ia,. Ik. Ik.Ca). The magnitude of the sodium channel conductance change was altered to meet several different types of impulse generation and propagation behaviors. We studied a range of model constraints which included variations in membrane resistance (Rm) from 4,000 Ω.cm2 to 100,000 Ω.cm2, and dendritic diameter from 0.1 to 0.3 μm. In a separate series of simulations, we studied the feasibility of voltage-clamping starburst amacrine cells using a soma-applied, single-electrode voltage clamp, based on models with and without dendritic and somatic spiking behavior. Our simulation studies suggest that single dendrites of starburst amacrine cells can behave as independent functional subunits when the Rm is high, provided that one or a small number of dendrites is synaptically co-activated. However, as the number of co-activated dendrites increases, the starburst cell behavior becomes more uniform and independent dendritic function is less prevalent. The presence of impulse activity in the dendrites raises new questions about dendritic function. However, dendritic impulses do not necessarily eliminate independent dendritic function, because dendritic impulses commonly fail as they propagate toward the soma, where they contribute EPSP-like responses which summate with conventional synaptic currents.