Reducing neuronal size results in less membrane and therefore lower input conductance. Smaller neurons are thus more excitable, as seen in their responses to somatic current injections. However, the impact of a neuron’s size and shape on its voltage responses to dendritic synaptic activation is much less understood. Here we use analytical cable theory to predict voltage responses to distributed synaptic inputs in unbranched cables, showing that these are entirely independent of dendritic length. For a given synaptic density, neuronal responses depend only on the average dendritic diameter and intrinsic conductivity. This remains valid for a wide range of morphologies irrespective of their arborization complexity. Spiking models indicate that morphology-invariant numbers of spikes approximate the percentage of active synapses. In contrast to spike rate, spike times do depend on dendrite morphology. In summary, neuronal excitability in response to distributed synaptic inputs is largely unaffected by dendrite length or complexity.

减小神经元尺寸会导致更少的膜，从而降低输入电导。因此，较小的神经元更容易兴奋，正如它们对体细胞电流注射的反应所见。然而，神经元的大小和形状对其电压对树突突触激活的反应的影响却鲜为人知。在这里，我们使用解析电缆理论来预测对未分支电缆中分布式突触输入的电压响应，表明这些完全独立于树突长度。对于给定的突触密度，神经元反应仅取决于平均树突直径和内在电导率。这对于广泛的形态仍然有效，而不管它们的树枝化复杂性如何。尖峰模型表明，形态不变的尖峰数近似于活跃突触的百分比。与尖峰速率相比，尖峰时间确实取决于枝晶形态。总之，响应分布式突触输入的神经元兴奋性在很大程度上不受树突长度或复杂性的影响。