Rate thresholds determine the precision of temporal integration in principal cells of the ventral cochlear nucleus
Rate thresholds determine the precision of temporal integration in principal cells of the ventral cochlear nucleus
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DOI：
10.1016/j.heares.2006.02.006
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发表时间：
2006-06-01
期刊：
影响因子：
2.8
通讯作者：
Oertel, Donata
中科院分区：
文献类型：
--
作者：
McGinley, Matthew J.;Oertel, Donata
腹侧耳蜗核 (VCN) 的三种主要细胞：丛状细胞、章鱼细胞和 T 星状细胞，在突触输入之间的一致性检测方面有所不同。为了探索动作电位生成机制在检测同时输入中的作用，我们检查了对以不同速率增加的去极化电流的响应。为了激发动作电位，浓密细胞（可能是球状亚型）的去极化速度必须快于 4.8 +/- 2.8 mV/ms，章鱼细胞的去极化速度必须快于 9.5 +/- 3.6 mV/ms，而 T 星状细胞则无论去极化速率如何都会放电。去极化的阈值速率允许定义时间窗口，在该时间窗口内去极化可以有助于产生动作电位。该整合窗口因细胞类型而异。浓密细胞为 5.3 +/- 1.8 ms，章鱼细胞为 1.4 +/- 0.3 ms。即使是缓慢的去极化，T 星状细胞也会发射动作电位，这表明它们的积分窗口是无限的，因此这些细胞中的时间总和受到突触电位时间过程的限制。 α-树突毒素降低了章鱼和浓密细胞的去极化阈值速率，而星状 T 细胞对 ot-树突毒素基本上不敏感，表明低电压激活的 K+ 电导 (g(KL)) 是积分窗口的重要决定因素。 (c) 2006 Elsevier B.V. 保留所有权利。
The three types of principal cells of the ventral cochlear nucleus (VCN), bushy, octopus, and T stellate, differ in the detection of coincidence among synaptic inputs. To explore the role of the action-potential-generation mechanism in the detection of coincident inputs, we examined responses to depolarizing currents that increased at varying rates. To fire an action potential, bushy cells, likely of the globular subtype, had to be depolarized faster than 4.8 +/- 2.8 mV/ms, octopus cells faster than 9.5 +/- 3.6 mV/ms, and T stellate cells fired irrespective of the rate of depolarization. The threshold rate of depolarization permitted definition of a time window over which depolarization could contribute to generating action potentials. This integration window differed between cell types. It was 5.3 +/- 1.8 ms for bushy cells and 1.4 +/- 0.3 ms for octopus cells. T Stellate cells fired action potentials in response to even slow depolarizations, showing that their integration window was unlimited so that temporal summation in these cells is limited by the time course of synaptic potentials. The rate of depolarization threshold in octopus and bushy cells was decreased by alpha-dendrotoxin while T stellate cells were largely insensitive to ot-dendrotoxin indicating that low-voltage-activated K+ conductances (g(KL)) are important determinants of the integration window. (c) 2006 Elsevier B.V. All rights reserved.