UNIS, UMR_S 1072, INSERM, Aix-Marseille Université, 13015 Marseille, France; Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
UNIS, UMR_S 1072, INSERM, Aix-Marseille Université, 13015 Marseille, France.
Curr Opin Neurobiol. 2018 Aug;51:37-44. doi: 10.1016/j.conb.2018.02.017. Epub 2018 Mar 8.
Axons link distant brain regions and are usually considered as simple transmission cables in which reliable propagation occurs once an action potential has been generated. Safe propagation of action potentials relies on specific ion channel expression at strategic points of the axon such as nodes of Ranvier or axonal branch points. However, while action potentials are generally considered as the quantum of neuronal information, their signaling is not entirely digital. In fact, both their shape and their conduction speed have been shown to be modulated by activity, leading to regulations of synaptic latency and synaptic strength. We report here newly identified mechanisms of (1) safe spike propagation along the axon, (2) compartmentalization of action potential shape in the axon, (3) analog modulation of spike-evoked synaptic transmission and (4) alteration in conduction time after persistent regulation of axon morphology in central neurons. We discuss the contribution of these regulations in information processing.
轴突连接着遥远的脑区，通常被认为是简单的传输电缆，一旦产生动作电位，就会可靠地传播。动作电位的安全传播依赖于轴突上特定离子通道的表达，如郎飞结或轴突分支点。然而，尽管动作电位通常被认为是神经元信息的量子，但它们的信号并非完全是数字的。事实上，它们的形状和传导速度都被证明可以被活动调节，从而调节突触潜伏期和突触强度。我们在这里报告了新发现的机制：（1）沿着轴突的安全尖峰传播；（2）轴突中动作电位形状的分区；（3）尖峰诱发的突触传递的模拟调制；（4）中枢神经元的轴突形态持续调节后的传导时间改变。我们讨论了这些调节在信息处理中的贡献。
