Sustained rhythmic activity in gap-junctionally coupled networks of model neurons depends on the diameter of coupled dendrites
Sustained rhythmic activity in gap-junctionally coupled networks of model neurons depends on the diameter of coupled dendrites
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DOI：
10.1152/jn.00648.2007
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发表时间：
2007-12-01
影响因子：
2.5
通讯作者：
Nadim, Farzan
中科院分区：
文献类型：
--
作者：
Gansert, Juliane;Golowasch, Jorge;Nadim, Farzan
众所周知，间隙连接对于许多网络功能非常重要，例如活动同步以及波和振荡的生成。间隙连接也被认为对于早期胚胎活动的产生至关重要。我们之前已经证明，通过间隙连接耦合无源电缆传播的电信号的幅度在独特的直径处最大化。这表明阈值相关信号可能会通过间隙连接在该最佳值周围的有限直径范围内传播。在这里，我们检查了树突耦合神经元模型网络中动作电位传播的直径依赖性。这些模型中的神经元具有被动体体和树突以及产生动作电位的轴突。我们表明，动作电位跨间隙连接的传播仅发生在有限范围的树突直径上，并且传播延迟取决于该直径。此外，在间隙连接耦合神经元网络中，当出现闭环（重入路径）时，就会出现节律性活动，但同样仅适用于有限范围的树突直径。这种节律活动的频率取决于路径的长度和树突直径。对于随机耦合神经元的大型网络，我们发现节律活动背后的重入路径也取决于树突直径。这些结果强调了树突直径作为间隙连接耦合网络中网络活动的决定因素的潜在重要性，例如在早期神经系统发育过程中观察到的网络节律。
Gap junctions are known to be important for many network functions such as synchronization of activity and the generation of waves and oscillations. Gap junctions have also been proposed to be essential for the generation of early embryonic activity. We have previously shown that the amplitude of electrical signals propagating across gap-junctionally coupled passive cables is maximized at a unique diameter. This suggests that threshold-dependent signals may propagate through gap junctions for a finite range of diameters around this optimal value. Here we examine the diameter dependence of action potential propagation across model networks of dendro-dendritically coupled neurons. The neurons in these models have passive soma and dendrites and an action potential-generating axon. We show that propagation of action potentials across gap junctions occurs only over a finite range of dendritic diameters and that propagation delay depends on this diameter. Additionally, in networks of gap-junctionally coupled neurons, rhythmic activity can emerge when closed loops (re-entrant paths) occur but again only for a finite range of dendrite diameters. The frequency of such rhythmic activity depends on the length of the path and the dendrite diameter. For large networks of randomly coupled neurons, we find that the re-entrant paths that underlie rhythmic activity also depend on dendrite diameter. These results underline the potential importance of dendrite diameter as a determinant of network activity in gap-junctionally coupled networks, such as network rhythms that are observed during early nervous system development.