Spike-frequency adaptation in the inferior colliculus
Spike-frequency adaptation in the inferior colliculus
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DOI：
10.1152/jn.00779.2003
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发表时间：
2004-02-01
影响因子：
2.5
通讯作者：
McAlpine, D
中科院分区：
文献类型：
--
作者：
Ingham, NJ;McAlpine, D
我们研究了乌拉坦麻醉的豚鼠下丘(IC)对耳间相位差(IPDS)敏感的神经元的尖峰频率适应，采用了一种旨在排除双耳整合水平以下适应影响的刺激范式。IPD阶跃刺激包括一个3,000毫秒的双耳音调，其中前1,000毫秒保持在神经元最不有利(“最差”)的IPD，调整出单耳分量，然后快速步进到神经元最有利(“最佳”)IPD，持续300毫秒。在某个可变间隔(1-1000ms)之后，IPD再次步进到最佳IPD，持续300ms，然后在刺激的其余部分返回到神经元最差的IPD。指数衰减函数对最佳IPD阶跃的反应表明，平均适应时间常数为52.9+/-26.4ms。从适应到最佳IPD步骤的恢复显示平均时间常数为225.5+/-210.2 ms。恢复时间常数与适应时间常数无相关性。在恢复期，适应第二个最佳IPD步骤的动力学与适应第一个最佳IPD步骤的动力学相似。刺激开始时的平均适应时间常数(最严重的IPD)为34.8+/-19.7ms，与对侧单独刺激时的38.4+/-22.1ms相似。刺激开始后的个体时间常数彼此相关，但与最佳IPD步骤中的时间常数无关。我们的结论是，这种双耳衍生的适应措施反映了发生在完全单耳通路水平之上的过程，以及在初级双耳相互作用地点之后的过程。
We investigated spike-frequency adaptation of neurons sensitive to interaural phase disparities (IPDs) in the inferior colliculus (IC) of urethane-anesthetized guinea pigs using a stimulus paradigm designed to exclude the influence of adaptation below the level of binaural integration. The IPD-step stimulus consists of a binaural 3,000-ms tone, in which the first 1,000 ms is held at a neuron's least favorable ("worst") IPD, adapting out monaural components, before being stepped rapidly to a neuron's most favorable ("best") IPD for 300 ms. After some variable interval (1-1,000 ms), IPD is again stepped to the best IPD for 300 ms, before being returned to a neuron's worst IPD for the remainder of the stimulus. Exponential decay functions fitted to the response to best-IPD steps revealed an average adaptation time constant of 52.9+/-26.4 ms. Recovery from adaptation to best IPD steps showed an average time constant of 225.5+/-210.2 ms. Recovery time constants were not correlated with adaptation time constants. During the recovery period, adaptation to a 2nd best-IPD step followed similar kinetics to adaptation during the 1st best-IPD step. The mean adaptation time constant at stimulus onset (at worst IPD) was 34.8+/-19.7 ms, similar to the 38.4+/-22.1 ms recorded to contralateral stimulation alone. Individual time constants after stimulus onset were correlated with each other but not with time constants during the best-IPD step. We conclude that such binaurally derived measures of adaptation reflect processes that occur above the level of exclusively monaural pathways, and subsequent to the site of primary binaural interaction.