Changes across time in the temporal responses of auditory nerve fibers stimulated by electric pulse trains
Changes across time in the temporal responses of auditory nerve fibers stimulated by electric pulse trains
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DOI：
10.1007/s10162-007-0108-5
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发表时间：
2008-03-01
影响因子：
2.4
通讯作者：
Abbas, Paul J.
中科院分区：
文献类型：
--
作者：
Miller, Charles A.;Hu, Ning;Abbas, Paul J.
大多数听觉假体使用调制的电脉冲串来激励听觉神经。然而，关于脉冲串对听觉神经纤维（ANF）反应的影响，在这种刺激的持续时间的数据很少。我们研究了时间ANF属性如何随着300 ms脉冲序列的水平和脉冲频率而变化。审查了四项措施：（1）第一峰潜伏期，（2）峰间期（ISI），（3）向量强度（VS），和（4）Fano因子（FF，反应性的时间变异性的指数）。使用250-、1，000-和5，000-脉冲/秒刺激获得数据。第一个尖峰潜伏期随着尖峰频率的增加而降低，对于5，000脉冲/秒的序列观察到相对较小的递减，推测反映了整合。低速率（250脉冲/秒）序列的ISI强烈锁定刺激，而5,000脉冲/秒序列诱发的ISI主要是不应性和适应性效应。随着时间的推移，VS降低低速率列车，但不是5,000脉冲/秒的刺激。在相对较高的尖峰频率（> 200尖峰/s）下，5，000脉冲/s序列的VS值低于250脉冲/s刺激获得的VS值（即使在考虑了5，000脉冲/s刺激的较小周期之后），表明高频率刺激的去极化效应。FF措施也表明了高速率列车的减污效果。在广泛的应答率范围内，FF经历了相对较快的增加（即，100 ms内）进行5，000脉冲/s刺激。除了少数例外，ISI，VS和FF措施接近渐近值内的300毫秒的持续时间的低和高速率列车。这些发现可能对人工耳蜗植入刺激方案的设计，电诱发复合动作电位的理解，以及在中央核团获得的神经测量的解释有影响，这取决于对听觉神经输出的理解。
Most auditory prostheses use modulated electric pulse trains to excite the auditory nerve. There are, however, scant data regarding the effects of pulse trains on auditory nerve fiber (ANF) responses across the duration of such stimuli. We examined how temporal ANF properties changed with level and pulse rate across 300-ms pulse trains. Four measures were examined: (1) first-spike latency, (2) interspike interval (ISI), (3) vector strength (VS), and (4) Fano factor (FF, an index of the temporal variability of responsiveness). Data were obtained using 250-, 1,000-, and 5,000-pulse/s stimuli. First-spike latency decreased with increasing spike rate, with relatively small decrements observed for 5,000-pulse/s trains, presumably reflecting integration. ISIs to low-rate (250 pulse/s) trains were strongly locked to the stimuli, whereas ISIs evoked with 5,000-pulse/s trains were dominated by refractory and adaptation effects. Across time, VS decreased for low-rate trains but not for 5,000-pulse/s stimuli. At relatively high spike rates (> 200 spike/s), VS values for 5,000-pulse/s trains were lower than those obtained with 250-pulse/s stimuli (even after accounting for the smaller periods of the 5,000-pulse/s stimuli), indicating a desynchronizing effect of high-rate stimuli. FF measures also indicated a desynchronizing effect of high-rate trains. Across a wide range of response rates, FF underwent relatively fast increases (i.e., within 100 ms) for 5,000-pulse/s stimuli. With a few exceptions, ISI, VS, and FF measures approached asymptotic values within the 300-ms duration of the low- and high-rate trains. These findings may have implications for designs of cochlear implant stimulus protocols, understanding electrically evoked compound action potentials, and interpretation of neural measures obtained at central nuclei, which depend on understanding the output of the auditory nerve.