Volen Center and Biology Department, Brandeis University, Waltham, United States.
Grass Laboratory, Marine Biological Laboratories, Woods Hole, United States.
Elife. 2019 Jan 18;8:e41728. doi: 10.7554/eLife.41728.
It is often assumed that highly-branched neuronal structures perform compartmentalized computations. However, previously we showed that the Gastric Mill (GM) neuron in the crustacean stomatogastric ganglion (STG) operates like a single electrotonic compartment, despite having thousands of branch points and total cable length >10 mm (Otopalik et al., 2017a; 2017b). Here we show that compact electrotonic architecture is generalizable to other STG neuron types, and that these neurons present direction-insensitive, linear voltage integration, suggesting they pool synaptic inputs across their neuronal structures. We also show, using simulations of 720 cable models spanning a broad range of geometries and passive properties, that compact electrotonus, linear integration, and directional insensitivity in STG neurons arise from their neurite geometries (diameters tapering from 10-20 µm to 2 µm at their terminal tips). A broad parameter search reveals multiple morphological and biophysical solutions for achieving different degrees of passive electrotonic decrement and computational strategies in the absence of active properties.
人们通常认为高度分支的神经元结构执行分区计算。然而，此前我们发现甲壳类动物口胃神经节（STG）中的胃磨（GM）神经元的运作方式类似于单个电紧张性隔室，尽管它有数千个分支点和总电缆长度>10 毫米（Otopalik 等人，2017a；2017b）。在这里，我们表明紧凑的电紧张性架构可推广到其他 STG 神经元类型，并且这些神经元呈现出方向不敏感的线性电压整合，这表明它们在神经元结构中汇集了突触输入。我们还通过模拟跨越广泛的几何形状和被动特性的 720 个电缆模型表明，STG 神经元中的紧凑电紧张、线性整合和方向不敏感源自它们的神经突几何形状（直径从 10-20 µm 逐渐变细到末端的 2 µm）。广泛的参数搜索揭示了多种形态和生物物理解决方案，可在没有主动特性的情况下实现不同程度的被动电紧张性衰减和计算策略。
