L-type calcium channels refine the neural population code of sound level.
L-type calcium channels refine the neural population code of sound level.
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L型钙通道细化声级的神经群体编码。
DOI：
10.1152/jn.00657.2016
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发表时间：
2016
影响因子：
2.5
通讯作者：
Sivaramakrishnan,Shobhana
中科院分区：
文献类型：
--
作者：
Grimsley,CalumAlex;Green,DavidBrian;Sivaramakrishnan,Shobhana
神经元集合对声级的编码提高了听者识别声音有多大的准确性。在听觉系统中，神经元对声级变化的反应速度由局部网络决定。电压门控电导通过调节神经元放电来改变局部输出，但它们在调节对声级的反应中的作用尚不清楚。我们研究了L型钙通道(CAL：CaV1.1-1.4)对听性中脑中央核下丘声级编码的影响。我们研究了钙对脑片总钙电流的贡献，然后通过清醒小鼠的单单位记录，研究了它对活体速率水平函数(RLF)的影响。∼是一种高阈值电流，占ICC神经元钙电流总量的50%。在体内，CaL在声音水平下激活，从而唤起高激发频率。在随声级单调增加的RFL中，CaL在高声级时提高尖峰频率，并增加所实现的最大发射频率。在随声级非单调变化的不同RLF群体中，CAL要么抑制或增强声音水平的激发，引起最大激发。CAL将单调RLF的增益与动态范围相乘，并将非单调RLF的增益除以RLF的宽度。这些结果表明，一类单一的钙通道激活增强和抑制局部回路，以调节神经元群体对声音水平的敏感性。
The coding of sound level by ensembles of neurons improves the accuracy with which listeners identify how loud a sound is. In the auditory system, the rate at which neurons fire in response to changes in sound level is shaped by local networks. Voltage-gated conductances alter local output by regulating neuronal firing, but their role in modulating responses to sound level is unclear. We tested the effects of L-type calcium channels (CaL: CaV1.1–1.4) on sound-level coding in the central nucleus of the inferior colliculus (ICC) in the auditory midbrain. We characterized the contribution of CaLto the total calcium current in brain slices and then examined its effects on rate-level functions (RLFs) in vivo using single-unit recordings in awake mice. CaLis a high-threshold current and comprises ∼50% of the total calcium current in ICC neurons. In vivo, CaLactivates at sound levels that evoke high firing rates. In RLFs that increase monotonically with sound level, CaLboosts spike rates at high sound levels and increases the maximum firing rate achieved. In different populations of RLFs that change nonmonotonically with sound level, CaLeither suppresses or enhances firing at sound levels that evoke maximum firing. CaLmultiplies the gain of monotonic RLFs with dynamic range and divides the gain of nonmonotonic RLFs with the width of the RLF. These results suggest that a single broad class of calcium channels activates enhancing and suppressing local circuits to regulate the sensitivity of neuronal populations to sound level.